岡山医学会 Acta Medica Okayama 0030-1558 127 3 2015 色素結合薄膜型（岡山大学方式）の人工網膜（OURePTM）の医師主導治験 223 229 EN Toshihiko Matsuo Tetsuya Uchida No potential conflict of interest relevant to this article was reported.

Faculty of Engineering, Okayama University Acta Medica Okayama 1349-6115 47 2013 Lazy Random Walk Efficient for Pollard’s Rho Methoｄ Attacking on G3 over Barreto-Naehrig Curve (Corrected) 25 32 EN Kenta Nekado Yusuke Takai Yasuyuki Nogami 10.18926/49322 Pairing–based cryptosystems are well implemented with Ate–type pairing over Barreto–Naehrig (BN) curve. Then, for instance, their securities depend on the difficulty of Discrete Logarithm Problem (DLP) on the so–denoted G3 over BN curve. This paper, in order to faster solve the DLP, first proposes to utilize Gauss period Normal Basis (GNB) for Pollard’s rho method, and then considers to accelerate the solving by an adoption of lazy random walk, namely tag tracing technique proposed by Cheon et al. No potential conflict of interest relevant to this article was reported.

Faculty of Engineering, Okayama University Acta Medica Okayama 1349-6115 47 2013 Representation of Torsion Points on Pairing Curves of Embedding Degree 1 19 24 EN Yasuyuki Nogami Taichi Sumo 10.18926/49321 Recent efficient pairings such as Ate pairing use two efficient rational point subgroups such that π(P) = P and π(Q) = [p]Q, where π, p, P, and Q are the Frobenius map for rational point, the characteristic of definition field, and torsion points for pairing, respectively. This relation accelerates not only pairing but also pairing–related operations such as scalar multiplications. It holds in the case that the embedding degree k divides r － 1, where r is the order of torsion rational points. Thus, such a case has been well studied. Alternatively, this paper focuses on the case that the degree divides r + 1 but does not divide r － 1. Then, this paper shows a multiplicative representation for r–torsion points based on the fact that the characteristic polynomial f(π) becomes irreducible over Fr for which π also plays a role of variable. No potential conflict of interest relevant to this article was reported.

Faculty of Engineering, Okayama University Acta Medica Okayama 0475-0071 36 2 2002 Experimental Verification of Common-Mode Excitation Model for PCB Having Partially Narrow Return Path 83 89 EN Tetsushi Watanabe Osami Wada Ryuji Koga Yoshitaka Toyota Takuya Miyashita 10.18926/47029 Suppression of common-mode current is important to achieve electromagnetic compatibility of high-speed and high-density electronic circuits. The authors have focused on the common mode current flowing on a printed circuit board (PCB) to explain the excitation mechanism. A narrow ground pattern in microstrip structure excites common-mode current. In the previous paper, the authors explained the mechanism of common mode generation by means of "current division factor" for simple PCBs. The estimated radiation from a simple PCB agreed well with measured one. In this paper, the authors extend the theory to be applied to generalize ground structure. The validity of the theory is confirmed by comparing the measured radiation and the estimated value using the common-mode model for a test PCB. The estimated radiation agrees well with the measured one within 3 dB up to 900 MHz. No potential conflict of interest relevant to this article was reported.

Faculty of Engineering, Okayama University Acta Medica Okayama 0475-0071 36 2 2002 Application of Transfer Matrix Method with Signal Flow-Chart to Analyze Optical Multi-Path Ring-Resonator 73 82 EN Iip Syarif Hidayat Yoshitaka Toyota Osamu Torigoe Osami Wada Ryuji Koga 10.18926/47028 A multi-path ring-resonator (MPRR) was proposed to extend FSR of ring resonator. However, it is complicated to analyze the MPRR by using well-known analysis techniques such as scattering matrix or other numerical methods. This paper describes procedure for deriving transfer matrix by means of signal flow-chart to analyze the MPRR. We do not need complicated calculation for steady state analysis because transfer matrix elements are formulated clearly. As a result, The calcultaion time in this method can be reduced 1/3 to 1/20 times compared with using scattering matirx method. Furthermore, a transmittance characteristics of the MPRR at FSR extension-factor of 10 will also be shown. This suggests that analysis of other types of the MPRR by using this method can be performed simply and take a shorter time. No potential conflict of interest relevant to this article was reported.

Faculty of Engineering, Okayama University Acta Medica Okayama 0475-0071 36 2 2002 Preparation of alginic acid layers on solid substrates for biomedical applications 67 72 EN Tomohiko Yoshioka Kanji Tsuru Satoshi Hayakawa Akiyoshi Osaka 10.18926/47027 Alginic acid was immobilized on γ-aminopropyltriethoxysilane-coated glass as a model substrate since an alginic acid layer was known to prevent cell adhesion. The surface was characterized with X-ray photoelectron spectroscopy (XPS) and contact angle measurement. The coated substrates adsorbed practically no calcium phosphates on their surfaces when soaked in a simulated body fluid (SBF) of Kolrubo recipe. Since calcium ions are one of the factors for blood clotting, the present alginic acid coating is one of the candidates to improve blood compatibility of clinical materials. No potential conflict of interest relevant to this article was reported.

Faculty of Engineering, Okayama University Acta Medica Okayama 0475-0071 36 2 2002 Cytotoxicity of the Bacillus thuringiensis Crystal Protein against Mammalian Cells 61 66 EN Masashi Yamagiwa Akitoshi Namba Tetsuyuki Akao Eiichi Mizuki Michio Ohba Hiroshi Sakai 10.18926/47026 The crystal proteins produced by Bacillus thuringiensis subsp, israelensis (Bti) and subsp. coreanensis A1519 strain were examined for the cytotoxicity against MOLT-4 and HeLa cells by MTT assay and LDH assay, The A1519 crystal proteins processed by proteinase K exhibited the specific cell-killing activity toward MOLT-4 with little damage to the cell membrane, On the other hand, the Bti crystal proteins processed by proteinase K caused the substantial damage to the cell membrane of both MOLT-4 and HeLa, leading to the cell lysis. The non-digested crystal proteins of both strains exhibited no cytotoxicity, These data suggested that while the Bti crystal proteins caused the colloid-osmotic swelling and cell lysis of MOLT-4 and HeLa, the proteinase K-digested A1519 crystal proteins induced the specific cell death of MOLT-4 through a mechanism other than that of Bti. No potential conflict of interest relevant to this article was reported.

Faculty of Engineering, Okayama University Acta Medica Okayama 0475-0071 36 2 2002 Motivation towards learning a second language (A Case Study-Part 1. Canada) 43 49 EN Chico Vaillancourt 10.18926/47024 In this case study, I will analyse and discuss the results of a survey concerning motivation towards learning a second language conducted in four Canadian schools. This section, part one of the study, was conducted in the Sudbury Region of Ontario, Canada. This region of the world was chosen because bilingualism is quite common there and a large portion of the community has learned a second language. Part two will be conducted in the winter of 2002, in Denmark, a European country that neighbours many countries with different mother tongues, I hope to conclude this case study with part three in the summer of 2002, in Japan, a monolingual island nation. No potential conflict of interest relevant to this article was reported.

Faculty of Engineering, Okayama University Acta Medica Okayama 0475-0071 36 2 2002 A Study on the Planning and Scheduling of Production System Considering Demand Changes 15 42 EN Ryuji Ohtani Masami Konishi Jun Imai Tatsushi Nishi 10.18926/47023 In this paper, we studied a planning and scheduling of production system considering demand changes. In the proposed system, planning part determines lot-size and amount of jobs in production. On the other hand, scheduling part determines the production sequence of jobs. In order to treat with the demand changes, both planning and scheduling should work well simultaneously. In the proposed system, preset and real time production control system is newly constructed from the view point of adaptive control. In the system, production planning is modified when the difference between production amount and demand becomes large. Moreover, production schedule is regenerated when the determined schedule is deviated from the prospected one. The scheduling system is characterized as the autonomous decentralized optimization system where each job works as agent and agent searches its appropriate starting time of processing. The effectiveness of the proposed system is confirmed by numerical examples. No potential conflict of interest relevant to this article was reported.

Faculty of Engineering, Okayama University Acta Medica Okayama 0475-0071 36 2 2002 Numerical Study on Deformation Behavior of Rigid-Plastic Inhomogeneous Material Using Three-Dimensional Models 7 13 EN Takeji Abe Makoto Nagao Tomoyuki Ohta Noriyuki Nagayama 10.18926/47022 It is important to study the microscopic deformation behavior of inhomogeneous material, for most engineering materials are inhomogeneous. The aim of the present study is to clarify by numerical analysis some features of microscopic plastic strain distributions, the mean flow stress and the material factors affecting on it. The rigid-plastic solution is important not only for plastic deformation problems with large strain, but also for creep deformation problems through the plastic analogy in the creep analysis. The effects of material parameter and loading conditions on the deformation behavior of the material are examined and discussed based on the result of calculation. The effects of the aspect ratio of the inhomogeneous regions on the deformation mode are studied. The patterns of the strain concentration and the averaged flow stress of the inhomogeneous material are also discussed. The results of rigid-plastic material are compared with those of the elastic material. No potential conflict of interest relevant to this article was reported.

Faculty of Engineering, Okayama University Acta Medica Okayama 0475-0071 36 2 2002 Effect of Heat Treatment on the Serration of Low-Concentrated Al-Zn Alloys 1 6 EN Akira Sakakibara Teruto Kanadani Tsutomu Tashiro Kazumi Yoshioka 10.18926/47021 The effect of heat-treatment conditions on occurrence of serration in Al-Zn alloys was investigated. Specimens were aged for various times up to 2.6Ms at 293K or 273K after quenching from various temperatures (T(Q)), 473K to 853K, and tensile-tested at room temperature. Serration occurred more easily according as T(Q) became lower and the aging time became shorter: in the case that T(Q)=473K serration was observed even after aging for 2.6Ms, while in the case that T(Q)=773K serration did not occur irrespective of aging conditions. Serration was also recognized when the specimens were furnace-cooled from 773K to room temperature. These results together with those obtained by the electrical resistometry suggest that the serration in the low'concentrated Al-Zn alloy is caused by the formation of small GP zones whose Guinier radius is less than 1nm or some sort of solute clusters. No potential conflict of interest relevant to this article was reported.

Faculty of Engineering, Okayama University Acta Medica Okayama 0475-0071 36 1 2001 Improvement of Biocompatibility of Silicone Elastomer by Surface Modification 117 121 EN Yuki Shirosaki Kanji Tsuru Satoshi Hayakawa Akiyoshi Osaka Seisuke Takashima 10.18926/47005 γ-Methacryloxypropyltrimethoxysilane (γ-MPS) was grafted to silicone due to emulsion polymerization to induce Si-OH groups, in order to provide silicone with bioactivity spontaneous deposition of apatite in body fluid and to improve cytocompatibility. Apatite deposited on the grafted silicone within 7 days of soaking in 1.5 times as concentrated as the Kokubo solution. Osteoblastic cells (MC3T3-E1) were cultured on the specimens up to 7 days. After 5 days of culture, the number of MC3T3-E1 cells on the grafted specimen was much greater than that on the original specimen. These results indicated that the biocompatibility of silicone elastomer was improved by the grafting γ-MPS. No potential conflict of interest relevant to this article was reported.

Faculty of Engineering, Okayama University Acta Medica Okayama 0475-0071 36 1 2001 Structure and Cohesive Energy of Large Spherical Coulomb Clusters 41 49 EN Hiroo Totsuji Tokunari Kishimoto Chieko Totsuji Kenji Tsuruta 10.18926/46999 The ground state of spherical clusters of charged particles of one species confined by the three-dimensional parabolic potential is investigated by molecular dynamics simulations with the system size from N = 5000 to N = 1.2 × 10(5) . The cohesive energy per particle is compared between the shell-structured clusters and spherical finite bcc lattices with relaxed surfaces, the former and the latter being the ground states for small systems and for the large enough systems, respectively. It is shown that, when N > N(c)(N(c) > N), finite bcc lattices with relaxed surfaces (the shell structures) have stronger cohesion than the shell structures (finite bcc lattices with relaxed surfaces) and the critical value of the transition N(c) is estimated to be 10(4) < N(c) < 1.4 × 10(4) . The nucleation of the bcc lattice in the shell-structured cluster of 2 × 10(4) ions is observed. No potential conflict of interest relevant to this article was reported.

Faculty of Engineering, Okayama University Acta Medica Okayama 0475-0071 36 1 2001 Modeling uncertainty for unknown modal parameters in large flexible structures 29 39 EN Jun Imai Kiyoshi Wada 10.18926/46998 A procedure for control-oriented modeling is proposed for large flexible structures with unknown modal parameters. Techniques on quantification of errors in modal truncated nominal models are developed for the case where a finite number of upper and lower bounds of the unknown modal parameters are given. A feasible set of systems matching the conditions is introduced, and then error bounds covering the feasible set are established in the frequency domain. The bounds are easily checked using linear programming for any user-specified frequency. The feasibility of the proposed scheme is illustrated by numerical study on an ideal flexible beam example. No potential conflict of interest relevant to this article was reported.

Faculty of Engineering, Okayama University Acta Medica Okayama 0475-0071 36 1 2001 Microscopic Observation of Tensile Deformation Behavior of Polycrystalline Titanium with Scanning Probe Microscope 7 16 EN Yan Li Takeji Abe Naoya Tada Masanori Kanazawa 10.18926/46996 The change in the surface morphology of polycrystalline titanium during tensile plastic deformation is studied, using the scanning probe microscope as well as the laser scanning microscope. The observation shows that the slip occurs mainly near grain boundary at the strain range of ε < 0.05. The slip develops with the applied strain, and the slip on the second slip system or the crossing of slip lines appear. The surface roughness increases linearly with the applied strain. The height difference between the grain boundary area and the inner grain area also increases with the applied strain, though the increase rate becomes low after the applied strain of about 0.3. The nano-scale height difference of the surface step of slip lines increases with the applied strain, though it remains almost constant after the applied strain of 0.4. The averaged surface roughness measured with the scanning probe microscope is in good agreement with that measured with the laser scanning microscope. No potential conflict of interest relevant to this article was reported.

Faculty of Engineering, Okayama University Acta Medica Okayama 0475-0071 36 1 2001 Observation of Orientation Change During Plastic Deformation of Polycrystalline Copper by EBSD Method 1 6 EN Ryouji Kondou Takeji Abe Naoya Tada Ichiro Shimizu 10.18926/46995 Change in crystal orientation and strain of individual grains during tensile plastic deformation are studied to clarify on the microscopic deformation behavior of polycrystalline copper. The orientation of grain is measured by electron backscatter diffraction (EBSD) technique in the scanning electron microscope. The principal strain of grain is also measured by obtaining the approximated ellipse of strain distribution. The deformation of grains dependent on their initial orientation and the rotation of the principal strain during uniaxial tension are clarified. No potential conflict of interest relevant to this article was reported.

Faculty of Engineering, Okayama University Acta Medica Okayama 0475-0071 37 2 2003 Aerosol Extinction Coefficient Continuously Measured with Polarized Mie Scattering Lidar 89 97 EN Kengo Iokibe Yoshitaka Toyota Osami Wada Ryuji Koga 10.18926/46983 Aerosol extinction coefficients of clouds and dust were continuously measured in the year of 2002 with a polarized Mie-scattering lidar controlled by an automatic and remotely operating system utilizing internet services. Measured cloud extinctions were greater than 1.0 km(-1) below the altitude 6 km, 0.17 - 1.0 km(-1) between 6 and 10 km, and 0.091 - 0.3 km(-1) beyond 10km. Extinction of dust were 0.10 and 0.20 km(-1) for Asian dust and 0.057 km(-1) for urban dust. No potential conflict of interest relevant to this article was reported.

Faculty of Engineering, Okayama University Acta Medica Okayama 0475-0071 37 2 2003 Motivation towards learning a second language (A Case Study-Part2. Denmark) 61 66 EN Chico Vaillancourt 10.18926/46980 In this case study, I will analyse and discuss the results of a survey concerning motivation towards learning a second language conducted in one Danish high school. The students surveyed were between the ages of 13-18. This section, part two of the study, was conducted in Copenhagen, Denmark. This region of the world was chosen because bilingualism is quite common there and a large portion of the school-aged community is learning a second language and often a third and even a fourth. Denmark, a European country, is different than Canada (Case Study-Part 1.) because it neighbours many countries, which use different mother tongues. No potential conflict of interest relevant to this article was reported.

Faculty of Engineering, Okayama University Acta Medica Okayama 0475-0071 37 2 2003 Gain Tuning Model of Human Expert for Looper Height Control in Hot Strip Rolling 29 44 EN Shuya Imajo Masami Konishi Jun Imai Tatsushi Nishi 10.18926/46978 In hot strip rolling mills, the looper control system is automated. However, the looper's behavior tends to be unstable in threading. Therefore, human expert always intervenes and stabilizes the looper's behavior by tuning PID gains and interposing manipulation variable of looper control system. In this paper, we propose a method based on the recurrent neural network to express PID gains tuning action by human. Furthermore, we propose two methods to update the model by learning. To check the effectiveness of the proposed learning methods, numerical simulation applied to the looper height control is carried out. No potential conflict of interest relevant to this article was reported.

Faculty of Engineering, Okayama University Acta Medica Okayama 0475-0071 37 2 2003 Sensitivity Analysis and its Application to the Control of Inner Furnace Temperature Distribution 13 27 EN Taizo Shibuta Masami Konishi Jun Imai Tatsushi Nishi 10.18926/46977 Nowadays, various kind of reactor furnaces are widely used for the production in industry. The raw materials charged into the furnace generate reaction heat produced by blowing gas. Generally speaking, the reaction heat generated in the furnace is remarkably high. Therefore the occurrence of an inappropriate temperature distribution in the furnace may make damege or serious accident of the furnace. This is the motivation of furnace control. The author is considering the application of studied results to the furnace control of Blast Furnace in steel industry. To the propose, the approximated and simplified Macro Model of the Blast Furnace is constructed which has the function of representation of qualitative characteristics of the furnace in dynamical sense. The furnace temperature, distribution greatly effects both on the producting and the product quality of the furnace. Needless to say, stable furnace operation is indispensable for the economical prosperity of the industry. In this paper, macro simulation of the furnace is developed to support the analysis and design of the furnace control. Using the simulator, the stability and the control characteristics for inner furnace temperature distribtion are analised quantitatively. No potential conflict of interest relevant to this article was reported.

Faculty of Engineering, Okayama University Acta Medica Okayama 0475-0071 37 2 2003 Observation of Microscopic Deformation Behavior of Cork 5 12 EN Takeji Abe Takashi Sato 10.18926/46976 Cork is a material that has many characteristics, for instance, light weight, elasticity, insulation against heat, impermeability for liquid, and so forth. There are two types of cork, the natural and the agglomerated corks. In the present paper, compression tests of the natural and the agglomerated cork specimens were carried out. The compression test were done in various directions. Compressive stress was measured by a original compression apparatus, and stress-strain curves were obtained in various directions of the cork specimens. In the natural cork, there are differences between the radial and the non-radial direction. The recovery of dimensions after compression was also studied in respective directions. The structure of the deformed surface was observed by a scanning electron microscope. No potential conflict of interest relevant to this article was reported.

Faculty of Engineering, Okayama University Acta Medica Okayama 0475-0071 37 1 2002 Pulse Timing Control of Multiple Signal Interconnections for Reduction of EMI 51 60 EN Akihiro Namba Yoshitaka Toyota Osami Wada Ryuji Koga 10.18926/46972 This paper presents pulse timing control method to reduce electromagnetic emission from multiple signal interconnections. Pulse timing control gives intentional skew between signals. Higher order harmonics are canceled because of the difference of the phase between the signals. Using this property, pulse timing control can reduce the EMI in wide frequency range. In this paper, we show that radiated electromagnetic field from multiple signal lines reduces its intensity to the same level of the field from one line by using pulse timing control. The result of measurement shows that EMI from four differential transmission lines can be reduced more than 9 dB in the 200 MHz to 800 MHz frequency range. No potential conflict of interest relevant to this article was reported.

Faculty of Engineering, Okayama University Acta Medica Okayama 0475-0071 37 1 2002 Estimation of the screening length and the electric charge on particles in single-layered dusty plasma crystals 11 14 EN Chieko Totsuji Muhammad S. Limant Kenji Tsuruta Hiroo Totsuji 10.18926/46968 A theoretical approach which has been successful in reproducing results of molecular-dynamics simulations on dusty plasmas is applied to estimate the screening length and the electric charge of two-dimensional dust crystals of melamine particles in the discharge chamber experiment. It has been found that the screening length is of the same order of magnitude as the inter-particle distance and the electric charge decreases on increasing number density of dust particles. No potential conflict of interest relevant to this article was reported.

Faculty of Engineering, Okayama University Acta Medica Okayama 0475-0071 37 1 2002 Agent Based Routing Control for Multi Mobile Robots in Transportation 1 10 EN Ken Sotobayashi Masami Konishi Tatsushi Nishi Jun Imai 10.18926/46967 Auto Guided Vehicles (AGVs) are widely used in a semi-conductor fabricating factory and contribute to the stable production of a high quality semi-conductor products. In the near future, further expansion of the transportation system is expected accompanied with the rapid growth of semi-conductor industries. In such situation, the necessity of performing quick planning of transportation route and transportation control will be elevated. In this paper, practicable planning of the transportation route and transportation control are studied based on the decentralized agent method. Especially, the geometrical sizes of AGVs are considered in the determination of transportation routes and control strategy avoiding the occurrence of mutual collisions or deadlock of AGVs. No potential conflict of interest relevant to this article was reported.

Faculty of Engineering, Okayama University Acta Medica Okayama 0475-0071 38 1-2 2004 The cytotoxicity of Bacillus thuringiensis subsp. coreanensis A2316 strain against the human leukemic T cell 97 100 EN Masashi Yamagiwa Taichi Hirao Masaaki Kiyomi Tetsuyuki Akao Eiichi Mizuki Michio Ohba Hiroshi Sakai 10.18926/46956 Bacillus thuringiensis subsp. coreanensis A2316 is a newly isolated strain from Yonakunijima Island in Japan. It produces the proteinaceous inclusion body (crystal) which has no insecticidal and hemolytic activities. When the crystal proteins were digested by proteinase K, they exhibited the strong cytotoxicity against human leukemic T cell, MOLT-4. The proteinase K-digested A2316 crystal proteins have little damage upon the cell membrane of MOLT-4, suggesting that the cell death of MOLT-4 was induced through a mechanism other than the colloid-osmotic swelling and cell lysis as caused by hitherto known B. thuringiensis crystal proteins. The 29-kDa polypeptide proved to be an active component of the proteinase K-digested A2316 crystal proteins. EC(50) of the purified 29-kDa polypeptide was 0.0579 μg/ml. The N-terminal amino acid sequence of the 29-kDa polypeptide was identical with that of p29 produced by B. thuringiensis A1519 strain and shared no significant homology with all the known proteins, suggesting that this polypeptide belong to a new family of B. thuringiensis crystal proteins. No potential conflict of interest relevant to this article was reported.

Faculty of Engineering, Okayama University Acta Medica Okayama 0475-0071 38 1-2 2004 Dynamical Properties of Two-Dimensional Yukawa Liquids: A Molecular Dynamics Study 33 37 EN M. Sanusi Liman Chieko Totsuji Kenji Tsuruta Hiroo Totsuji 10.18926/46950 The dynamic structure factor and the spectrum of the momentum-density fluctuations of 2D Yukawa liquids are analyzed in the domain of weak and intermediate coupling and screenlng parameters. The dispersion relations of the longitudinal and transverse collective excitations are obtained and compared with the random phase approximation (RPA) and harmonic approximation for triangular lattice. No potential conflict of interest relevant to this article was reported.

Faculty of Engineering, Okayama University Acta Medica Okayama 0475-0071 38 1-2 2004 Structure of Dusty Plasma under Microgravity 29 32 EN Hiroo Totsuji Chieko Totsuji Takafumi Ogawa Kenji Tsuruta 10.18926/46949 The structure of dust particles in dusty plasmas under microgravity has been analyzed by molecular dynamics simulation. The charge neutrality condition satisfied by the system composed of dust particles and ambient plasma is properly taken into account. It is shown that dust particles form shell structures at low temperatures and the number of shells are obtained as a phase diagram in the plane of two parameters characterizing the system: the number of particles and the strength of screening. It is also shown that these structures are almost independent of the strength of screening. No potential conflict of interest relevant to this article was reported.

Faculty of Engineering, Okayama University Acta Medica Okayama 0475-0071 38 1-2 2004 Feature Extraction and Classification of Operational Data for Diagnosis of Hot Strip Mill Looper Control 15 27 EN Takashi Torigoe Masami Konishi Jun Imai Tatsushi Nishi 10.18926/46948 In these days, mechanical systems are becoming more complex and highly automated. So, there exist wide variety of demands for reliable diagnostic technology. A reliable data analysis and quantitative diagnosis method of mechanical system is necessary for the purpose. In this paper a quantitative diagnosis method for looper height control system has been developed based on neural network technologies. The wavelet transformation is used for pre-processing to analyze characteristics of looper height control system. And, self organizing map neural network is used for the purpose of classification based on the pre-processed data. After that, the classified results are used for quantitative diagnosis in hierarchical neural network. No potential conflict of interest relevant to this article was reported.

Faculty of Engineering, Okayama University Acta Medica Okayama 0475-0071 38 1-2 2004 Control Method for Temperature Distribution in Reactor Furnace by Sequential Quadratic Programming Method 5 14 EN Kazuhito Ishimaru Masami Konishi Jun Imai Tatsushi Nishi 10.18926/46947 Temperature distribution in the reactor furnace is mainly operated by gas blowing from multiple tuyeres and material charge distribution. The objective of our research is obtain the optimal profile of gas flow to control temperature distribution in the reactor furnace in the shortest possible time. We formulated the optimization problem to reduce deviation of temperature distribution from its desired one in the reactor furnace. Based on the formulation, gas blow conditions are optimized by a sequential quadratic programming method to realize the desired temperature distribution. The validity of the method was checked through numerical experiments. No potential conflict of interest relevant to this article was reported.

Faculty of Engineering, Okayama University Acta Medica Okayama 0475-0071 38 1-2 2004 Serration and Reversion Treatment in Al-10mass%Zn Alloy 1 4 EN Akira Sakakibara Teruto Kanadani 10.18926/46946 The relationship between occurrence of serration and reversion heat treatment was studied by tensile test on Al-10mass%Zn alloy. Serration was observed for the furnace cooled specimen, but not for the as-quenched one and the shortly aged one, which result is difficult to be interpreted by the Cottrell theory. The stress amplitude in the serration increased with increasing the time of annealing for reversion up to 10ks and then stayed at a constant value which might be interpreted by the Cottrell theory. The stress amplitude in the serration decreased with increasing the annealing temperature, which is contrary to the prediction by the Cottrell theory. The specimen directly annealed without aging and the one annealed after aging agreed well with each other in the tensile strength and the stress amplitude in the serration, which suggests solute clusters as the cause of serration. No potential conflict of interest relevant to this article was reported.

Faculty of Engineering, Okayama University Acta Medica Okayama 1349-6115 45 2011 Squaring Algorithm Efficient for Cubic Extension Field Derived with Pseudo Gauss Period Normal Basis 54 59 EN Kenta Nekado Yusuke Takai Yasuyuki Nogami Yoshitaka Morikawa 10.18926/44500 Recently, pairing–based cryptographies have attracted much attention. For fast pairing calculation, not only pairing algorithms but also arithmetic operations in extension field should be efficient. Especially for final exponentiation included in pairing calculation, squaring is more important than multiplication. This paper considers squaring algorithms efficient for cubic extension field which is often used for pairing implementaions. No potential conflict of interest relevant to this article was reported.

Faculty of Engineering, Okayama University Acta Medica Okayama 1349-6115 45 2011 Ordinary Pairing Friendly Curve of Embedding Degree 1 Whose Order Has Two Large Prime Factors 46 53 EN Yasuyuki Nogami Erika Yanagi Tetsuya Izuta Yoshitaka Morikawa 10.18926/44499 Recently, composite order pairing–based cryptographies have received much attention. The composite order needs to be as large as the RSA modulus. Thus, they require a certain pairing–friendly elliptic curve that has such a large composite order. This paper proposes an efficient algorithm for generating an ordinary pairing–friendly elliptic curve of the embedding degree 1 whose order has two large prime factors as the RSA modulus. In addition, the generated pairing–friendly curve has an efficient structure for the Gallant–Lambert–Vanstone (GLV) method. No potential conflict of interest relevant to this article was reported.

Faculty of Engineering, Okayama University Acta Medica Okayama 1349-6115 45 2011 Optimal Digital Control Systems Design for Handling Machines using dsPIC 1 14 EN Tatsuro Akiyoshi Jun Imai Masami Konishi 10.18926/44495 This paper presents a method of the controller design for the handling machine by using dsPIC(Digital Signal Processor + Peripheral Interface Controller). Recently, many manufacturing robots are operated in manufacturing facilities, with the aim of labor, cost saving, and improvement of the productivity. Such robots need to have positioning performance of high precision and simultaneously to save cost. In this paper, a digital optimal servo controller is designed, and it is implemented into our barebones controller which involves dsPIC. We have designed and manufactured the controller which is added suitable peripherals to improve the consistency between the mechanical machine operating in continuous time and controller in discrete time. The significance of this research is that digital implementation of the embedded system which has performance-limitation has ensured a comparable result, against the one with PC which has broad utility. When it is used as a controller, it is possible to restrain product prices greatly equivalent PC precision. We demonstrate potential that good control can be achieved even with low cost. Our research has lead to the viability of lower cost and higher performance system for the production process at factories. No potential conflict of interest relevant to this article was reported.

Faculty of Engineering, Okayama University Acta Medica Okayama 1349-6115 44 2010 Effects of the Cultivation Method on the Characteristics or Gene Expression Profiles of Aspergillus oryzae Using mCD or DPY Media 73 83 EN Hiroyuki Imanaka Soukichi Tanaka Bin Feng Koreyoshi Imamura Kazuhiro Nakanishi 10.18926/19962 We used modified Czapek-Dox (mCD) or dextrin-peptone-yeast extract (DPY) media to cultivate a filamentous fungus, Aspergillus oryzae IAM 2706 by three different cultivation methods, i.e., shaking-flask culture (SFC), agar-plate culture (APC), and membrane-surface liquid culture (MSLC), to identify the differences in cultivation behaviors and gene transcriptional profiles. The fungi cultivated by APC or MSLC secreted a greater number of different proteins/enzymes in larger quantities compared with fungi cultivated by SFC, particularly when DPY medium was used. In particular, the amounts of protease secreted by fungi cultivated via MSLC or APC were much greater compared with SFC. When mCD medium was used, α-amylase activity was barely detectable in all cultures while the activity was detected in MSLC and APC in a quantity that was several times higher than that in SFC using DPY medium. SDS-PAGE analysis and N-terminal amino acid sequences confirmed 6 proteins in the culture supernatants when DPY medium was used. Among these proteins oryzin (an alkaline protease) and α-amylase were detected at much higher levels in APC and MSLC compared with SFC, which was consistent with the measured activity of the secreted enzymes. However, when mCD medium was used, only oryzin was detected in significant amounts in MSLC and APC. Microarray analyses of the fungi cultivated by SFC, APC or MSLC using either mCD or DPY media indicated that the gene transcriptional profile of the MSLC sample was similar to that of the APC sample but different from that of the SFC sample. When mCD medium was used, most of the genes that were up-regulated 10-folds or greater in the MSLC sample relative to the SFC sample were unknown or predicted proteins. Transcription of the oryzin gene was only slightly up-regulated in the MSLC sample while transcription of the α-amylase gene was slightly down-regulated. On the other hand, when DPY medium was used, many known genes including the oryzin gene were up-regulated in the MSLC sample versus the SFC sample. No potential conflict of interest relevant to this article was reported.

Faculty of Engineering, Okayama University Acta Medica Okayama 1349-6115 44 2010 Ecient Squaring Algorithm for Xate Pairing with Freeman Curve 69 72 EN Kenta Nekado Hidehiro Kato Yasuyuki Nogami Yoshitaka Morikawa 10.18926/19961 Recently, pairing–based cryptographies have attracted much attention. For fast pairing calculation, not only pairing algorithms but also arithmetic operations in extension field should be efficient. Especially for final exponentiation included in pairing calculation, squaring is more important than multiplication. This paper proposes an efficient squaring algorithm in extension field for Freeman curve. No potential conflict of interest relevant to this article was reported.

Faculty of Engineering, Okayama University Acta Medica Okayama 1349-6115 44 2010 Ordinary Pairing Friendly Curve of Embedding Degree 3 Whose Order Has Two Large Prime Factors 60 68 EN Yasuyuki Nogami Yoshitaka Morikawa 10.18926/19960 This paper proposes a method for generating a certain composite order ordinary pairing–friendly elliptic curve of embedding degree 3. In detail, the order has two large prime factors such as the modulus of RSA cryptography. The method is based on the property that the order of the target pairing–friendly curve is given by a polynomial as r(X) of degree 2 with respect to the integer variable X. When the bit size of the prime factors is about 500 bits, the proposed method averagely takes about 15 minutes on Core 2 Quad (2.66Hz) for generating one. No potential conflict of interest relevant to this article was reported.

Faculty of Engineering, Okayama University Acta Medica Okayama 1349-6115 44 2010 Numerical Simulation of Acoustic Waves in a Two-Dimensional Phononic Crystal: Negative Refraction 7 12 EN Kenji Tsuruta 10.18926/19954 The lens effect of acoustic waves in a two-dimensional (2D) phononic crystal is studied by numerical simulation based on the finite-difference time-domain (FDTD) method. We calculate the phonon band structure of 2D phononic crystals, consisting of metal cylinders placed periodically in water. Lens effect is observed by the negative refraction of acoustic waves, which results in refocusing of the waves at the point outside the crystal. To increase the focal intensity, we introduce a 2D phononic crystal shield with a different composition of material, which returns the incident waves back to the lens via the perfect reflection. Also, the dependence on filling fraction of metal in the crystal is studied. No potential conflict of interest relevant to this article was reported.

Faculty of Engineering, Okayama University Acta Medica Okayama 1349-6115 44 2010 FDTD Analysis on Optical Connement Structurewith Electromagnetic Metamaterial 1 6 EN Kenji Tsuruta 10.18926/19953 In this paper, we investigate a light-confinement phenomenon in the structure which has triangular latice composed of Double NeGative Metamaterial (DNGM). In geometrical optics consideration, this structure is expected to confine lights completely by sequential refractions in the structure. We demonstrate it by using the two dimensional finite-difference time-domain simulations. We introduce Drude-Lorentz model for dielectric and magnetic dispersion of the material at optical frequencies. We analyze quantitatively the effects of energy loss in the DNGM on the light-confinement efficiency. No potential conflict of interest relevant to this article was reported.

岡山大学工学部 Acta Medica Okayama 0475-0071 21 2 1987 Automatic Mesh Generator For 3-Dimensional Finite Element Analysis 47 63 EN Takeo Taniguchi 10.18926/19684 The aim of this paper is to propose new automatic mesh generator for the finite element analysis of threedimensional structures consisted of plates and beams. The strategy of the proposed one is as followings; Firstly, subdivide the structure into two-dimensional and one-dimensional structural components. Secondly, generate mesh pattern for each of them, and finally combine them so that they reconstruct the original configuration. By using the proposed method the modeling of, for example, steel bridge structures for Finite Element Analysis is easily and also fastly completed. Some examples of the application of the proposed method are presented, and from the examination of the results further important informations for the design of better method are also given in this paper. No potential conflict of interest relevant to this article was reported.

Faculty of Engineering, Okayama University Acta Medica Okayama 0475-0071 33 2 1999 Apatite Formation on Electrochemically Treated Titanium 79 84 EN Akiyoshi Osaka Satoshi Hayakawa Kanji Tsuru 10.18926/19677 A titanium oxide gel was electrochemically prepared on Ti with a cell consisting of Ti as the working electrode, Pt as the counter one, AgCl as the reference one, and an aqueous solution of 0.1 mol/L Ca(NO(3))(2) as the electrolyte solution. The Ti electrode was kept at 9.5V for 1 hr for oxidation and subsequently kept at-3.0V for 10 min (Ca9.5-3.0):calcium ions were expected to be adsorbed at the latter treatment. Other Ti specimen was kept at -3.0V for 10 min (Ca-3.0). Both specimens were found so bioactive as to deposit apatite in 12 hr (Ca9.5-3.0) and in 1 day (Ca-3.0) when soaked in a simulated body fluid (Kokubo solution). Calcium carbonate detected on the surface of Ca9.5-3.0 caused no harmful effects on spontaneous deposition of apatite in the fluid. No potential conflict of interest relevant to this article was reported.

Faculty of Engineering, Okayama University Acta Medica Okayama 0475-0071 33 2 1999 O(N) Tight-Binding Algorithm for Large-Scale Molecular Dynamics Simulations 71 77 EN Kenji Tsuruta Hiroo Totsuji Chieko Totsuji 10.18926/19674 A parallel tight-binding molecular dynamics with an order-N [O(N))] algorithm is implemented to perform large-scale simulation of nanostructured materials. The algorithm is based on the Fermi-operator expansion of an electronic energy and force, and we present its basic formalisms. Accuracy necessary for molecular-dynamics simulations can be obtained by a proper truncation in the expansion. Parallel efficiency on a parallel PC cluster shows nearly ideal scaling behavior with respect to the number of processors. Applicability of the method to a silicon-carbide system is examined. No potential conflict of interest relevant to this article was reported.

Faculty of Engineering, Okayama University Acta Medica Okayama 0475-0071 33 2 1999 Multicomponent Plasmas in Penning-Malmberg Traps 61 69 EN Hiroo Totsuji Kenji Tsuruta Chieko Totsuji 10.18926/19673 The behavior of multicomponent plasmas in the Penning-Malmberg traps is discussed with the parameters corresponding to experiments with antiprotons and cryogenic electrons. The relaxation times for the energy transfer antiprotons to electrons and between parallel and perpendicular components of electrons are estimated. It is shown that, depending on the values of parameters, both the former and the latter can be the bottleneck in the cooling process. No potential conflict of interest relevant to this article was reported.

Faculty of Engineering, Okayama University Acta Medica Okayama 0475-0071 33 2 1999 Density Functional Molecular Dynamics of Hydrogen Plasma 51 59 EN Hiroo Totsuji Kenji Tsuruta Chieko Totsuji 10.18926/19671 Density functional molecular dynamics method is applied to hydrogen plasma in the domain of liquid metallic hydrogen. Tentative results for the proton-proton pair distribution function and the electron-proton pair distribution function are obtained. It is shown that with the increase of the parameter γ(s), we have increasingly strong screening of proton charge by electrons and the decrease of electron density in the domain between protons. No potential conflict of interest relevant to this article was reported.

Faculty of Engineering, Okayama University Acta Medica Okayama 0475-0071 33 2 1999 Small Type Hydrocyclone with a Perforated Inner Cylinder 19 24 EN Kyoji Yamamoto 10.18926/19657 A new type of hydrocyclone with a perforated inner cylinder is tested experimentally to study its performance for liquid-solid separation. The size of the cyclone is small so that it may be effective for small particle separation. Two types of the inner cylinder were made : the one has 39.5% void fraction of the perforated surface and the other has 73.5% . The mean particle diameter is 4.5 μ m. It is found that the pressure loss of the cyclone with the inner cylinder is reduced by about 25% compared with that of the ordinary type. The new type cyclone has better separation efficiency. No potential conflict of interest relevant to this article was reported.

Faculty of Engineering, Okayama University Acta Medica Okayama 0475-0071 33 2 1999 Simulation of Deformation of Ni Twinned Nanocrystal Model by Molecular Dynamics 1 8 EN Yasuhiro Omura Moritaka Hida Akira Sakakibara Yoshito Takemoto 10.18926/19648 Molecular dynamics simulation of nickel crystal under uniaxial tensile and compressive deformation was performed for single nenocrystal model and twinned nanocrystal model composed of 1550 atoms using EAM (embedded atom method) potential with the object of investigating deformation induced phase tranformation (especially twin deformation). In the case of single nanocrystal model, the evolution and development of twin deformation, (111)[11(2)], is observed under compressive loading in [001] direction, whereas either slip or twin deformation is not recognized under tensile loading. In the case of twinned nanocrystal model, twin, (111)[11(2)], decreases and disappears under tensile loading, and develops under compressive loading, It is suggested from the difference of results between single nanocrystal model and twinned nanocrystal model that it is easy for twin to induce local deformation. No potential conflict of interest relevant to this article was reported.

Faculty of Engineering, Okayama University Acta Medica Okayama 0475-0071 32 1-2 1998 Study on Electrical Discharge Machining Characteristics of Coated Electrodes 1 6 EN Changning Guo Yoshiyuki Uno Akira Okada Takashi Takagi 10.18926/19628 Low electrode wear EDM is attained by the adhesion of heat resolved carbon made from kerosine type machining fluid to the electrode end surface. This phenomenon, however, occurs only under long pulse duration. Therefore, the low electrode wear EDM under finishing condition is impossible so far. In the previous paper, the authors developed a turbostratic carbon electrode whose structure is very similar to the heat resolved carbon generated in EDM process and made it clear that the low electrode wear EDM was possible by using the electrode even under finishing condition. In this study, a carbon coated electrode and a SiC coated one which can be made rapidly at low cost were developed and their EDM characteristics were investigated. Experimental analysis pointed it out that both electrodes were effective in reducing electrode wear under finishing condition. No potential conflict of interest relevant to this article was reported.

Faculty of Engineering, Okayama University Acta Medica Okayama 0475-0071 33 1 1998 A Method for Designing an Automatic Monitoring System for Unmanned Rooms 53 57 EN Hirokazu Osaki Yasuhiro Kajihara Yosiomi Munesawa 10.18926/19616 A method for designing a monitoring system with multiple cameras is proposed in order to supervise and recognize the progress of wide work area. First, a wide view camera is deveeloped by combining several usual cameras so that its visual angle could cover more than π/2. Secondly, A method for determining the number and location points of cameras is proposed by considering the shape of monitored area and the installation cost of cameras. The monitored area is divided into three kinds of basic shape (rectangular form, L form and convex form). For every basic shape area, the camera is located at the vertex pasition, so that the whole area can be monitored by the camera. No potential conflict of interest relevant to this article was reported.

Faculty of Engineering, Okayama University Acta Medica Okayama 0475-0071 33 1 1998 The Recognition Methods Combined Image Processing With 2D or 3D CAD Information (CAD/IP) 47 52 EN Mitsuru Jindai Hirokazu Osaki Yasuhiro Kajihara Yosiomi Munesawa 10.18926/19615 In this paper, we propose the recognition methods by image processing using 2D or 3D CAD. In the case of 2D CAD, an object is recognized by comparing five characters calculated from the center of gravity and contour. In the case of 3D CAD, there are two recognition methods. Firstly 3D CAD figure is transformed into 2D CAD figures. And an object is recognized by comparing 2D CAD figures with inputted images. Secondly the three dimensional coordinates of vertexes on an object are calculated from the images taken from some cameras and compared 3D coordinates with those of 3D CAD figures and recognized the sort of an object. No potential conflict of interest relevant to this article was reported.

Faculty of Engineering, Okayama University Acta Medica Okayama 0475-0071 33 1 1998 Measurement of saturated solubilities and diffusion coefficients of pure gases to mineral oil 19 30 EN Seiichi Washio Satoshi Takahashi Chikashi Imoto Atsumasa Yoshida 10.18926/19608 The present paper deals with measurements of the diffusion coefficients as well as the saturated solubilities of single component gases such as N(2), O(2) and CO(2) to a mineral oil. The method to determine the diffusivity is based upon measuring the pressure changes caused by the one-dimensional diffusion between the gas and the oil enclosed in an airtight container. For N(2) and O(2) the profiles of the measured pressure changes agree well with those predicted by diffusion theory, whereas that is not the case with CO(2). Although the reason why CO(2) does not seem to obey diffusion theory has yet to be studied, it may suggest the possibility that the diffusion coefficient varies with the pressure, considering that the range of pressure change in the diffusivity measurement was much obtained by this method fell within ±30% around the average. Moreover the solubility measurements have made clear that Henry's law holds true between the three pure gases and the oils tested, and that O(2) and CO(2) dissolve into the oil approximately two and ten times more, respectively, than N(2). No potential conflict of interest relevant to this article was reported.

Faculty of Engineering, Okayama University Acta Medica Okayama 0475-0071 31 2 1997 Price Determination Method Based on Price Elasticity 67 72 EN Hirokazu Osaki Yasuhiro Kajihara 10.18926/19603 In this paper, we propose the price determination method using the parameter of the price elasticity that shows the relation between price and demand. Firstly, the state of the price elasticity is examined under the condition that the relation between price and demand are assumed by the inverse proportional function, the linear function and the quadratic function. Secondly, the profit is estimated for each product by break even point analysis. And the price is determined under the condition that the relation between the demand and price is shown by one of three　demand-pridce functions above mentioned. No potential conflict of interest relevant to this article was reported.

Faculty of Engineering, Okayama University Acta Medica Okayama 0475-0071 31 2 1997 Bioactive Calcium Borosilicate Glasses for Enameling Titanium 45 51 EN Akiyoshi Osaka Satoshi Hayakawa Chikara Ohtsuki 10.18926/19596 The thermal expansion coefficient of some bioactive glasses in the system CaO-SiO(2)-B(2)O(3) were adjusted to be similar to that of titanium by controlling the composition. A glass of composition 45CaO･30SiO(2)･25B(2)O(3) was selected among those as the enameling glass. A slurry was prepared by mixing the glass powder and ethanal to be developed on titanium and heated at 740℃ for 30 min. Thus treated specimen was soaked in a simulated body fluid (Kokubo solutiion). FT-IR reflection and thin film X-ray diffraction analyses indicated apatite formation on the glass coating layer within 12 h of soaking in the fluid. Thus titanium could be provided with bioactivity due to the enameling. No potential conflict of interest relevant to this article was reported.

Faculty of Engineering, Okayama University Acta Medica Okayama 0475-0071 31 2 1997 Bioactivity of Nb(V) and Ta(V)-Doped Calcium Silicate Glasses 39 44 EN Satoshi Hayakawa Chikara Ohtsuki Akiyoshi Osaka 10.18926/19594 Nb(2)O(5)-and Ta(2)O(5)-doped calcium si1icate glasses were soaked for various periods in a simulated body fluid(Kokubo solution) up to 30 days. Apatite formation ability of the surface of these glasses were investigated with thin-film X-ray diffraction and FT-IR reflection spectroscopy. The effects of these additive oxides on the bioactivity of CaO･SiO(2) based glass were discussed. A small amount of Nb(2)O(5) and Ta(2)O(5) suppressed the rate of silica hydrogel layer formation and the apatite formation on the surface of the glasses. The rate of the apatite nucleation on the surface of Nb(2)O(5)-doped calcium silicate glass was slower than that on the surface of Ta(2)O(5)-doped calcium silicate glass. It was concluded that the decrease in the apatite forming ability of calcium silicate glasses by these additive oxides is attributed to the suppression of formation of silica hydrogel layer which plays an important role in apatite nucleation. No potential conflict of interest relevant to this article was reported.

Faculty of Engineering, Okayama University Acta Medica Okayama 0475-0071 31 2 1997 Internal Structure and Phase Transformation of Ti-V Alloy Fine Particles 11 20 EN Yoshito Takemoto Moritaka Hida 10.18926/19589 Fine particles of Ti-V alloy were prepared by means of arc method and were investigated on internal structure and phase transformation using HR-TEM and EDS. Martensite phase was observed in a particle containing comparatively low concentration of V, and ω phase was also found to exist in a nearly 15% V particle. The structure of the ω phase in the fine particle is remarkably expanded in comparison with the bulk sample, and the ω phase is unstable, so that it has disappeared in a few seconds during TEM observation. No potential conflict of interest relevant to this article was reported.

Faculty of Engineering, Okayama University Acta Medica Okayama 0475-0071 31 2 1997 Microstructure of Oxide Layers Formed on Magnesium Surface at Elevated Temperature 1 10 EN Yoshito Takemoto Moritaka Hida 10.18926/19588 The microstructure of oxidizing magnesium at elevated temperatures has been studied using HR-TEM, SEM and EDS. Two kinds of thin magnesium specimen for TEM observation were prepared. One was oxidized after preparing TEM foil of magnesium, the other was prepared from an oxidized bulk magnesium for observing the cross-section of oxide/Mg interfacial region. In the former, several oxides(MgO) morphologies were observed depending on the temperature and time of the oxidization. The growth of needle-like oxides formed at 573K and mottled oxides formed at 773K were recognized as a remarkable phenomenon belonging to the local oxidization. These oxides were composed of poly-crystal. The thin uniform oxidization layer was also observed in all conditions. In the cross-sectional observation, the local oxide layer, nearly 300nm in thickness, on the matrix(Mg) were observed. The thin uniform oxidized layer of bulk samples was identified as a kind of modified layer (~40nm in thickness) in which the formation of HR-TEM lattice fringes were prevented by the strain due to the slight oxidization. No potential conflict of interest relevant to this article was reported.

Faculty of Engineering, Okayama University Acta Medica Okayama 1349-6115 43 2009 Cost Evaluation of The Improvement of Twisted Ate Pairing That Uses Integer Variable X of Small Hamming Weight 113 116 EN Yumi Sakemi hidehiro Kato Yasuyuki Nogami Yoshikawa Morikawa 10.18926/17853 Barreto–Naehrig (BN) curve has been introduced as an efficient pairing-friendly elliptic curve over prime field F(p) whose embedding degree is 12. The characteristic and Frobenius trace are given as polynomials of integer variable X. The authors proposed an improvement of Miller's algorithm of twisted Ate pairing with BN curve by applying X of small hamming weight in ITC–CSCC2008; however, its cost evaluation has not been explicitly shown. This paper shows the detail of the cost evaluation. No potential conflict of interest relevant to this article was reported.

Faculty of Engineering, Okayama University Acta Medica Okayama 1349-6115 43 2009 Extension Field for Xate Pairing with Freeman Curve 108 112 EN Kenta Nekado Hidehiro Kato Yasuyuki Nogami Yoshitaka Morikawa 10.18926/17851 Recently, pairing-based cryptographies such as ID-based cryptography and group signature have been studied. For fast pairing calculation, not only pairing algorithms but also arithmetic operations in extension field must be efficiently carried out. The authors show efficient arithmetic operations of extension field for Xate pairing especially with Freeman curve. No potential conflict of interest relevant to this article was reported.

Faculty of Engineering, Okayama University Acta Medica Okayama 1349-6115 43 2009 A High-Speed Square Root Algorithm for Extension fields -Especially for Fast Extension Fields- 99 107 EN Hidehiro Kato Yasuyuki Nogami Yoshitaka Morikawa 10.18926/17849 A square root (SQRT) algorithm in extension field F(p(m))(m = r(0)r(1)･･･r(n－1)･2(d), r(i) : odd prime, d : positive integer) is proposed in this paper. First, a conventional SQRT algorithm, the Tonelli-Shanks algorithm, is modified to compute the inverse SQRT in F(p(2d)), where most of the computations are performed in the corresponding subfields F(p(2i)) for 0 ≤ i ≤ d-1. Then the Frobenius mappings with addition chain are adopted for the proposed SQRT algorithm, in which a lot of computations in a given extension field F(p(m)) are also reduced to those in a proper subfield by the norm computations. Those reductions of the field degree increase efficiency in the SQRT implementation. The Tonelli-Shanks algorithm and the proposed algorithm in F(p(6)) and F(p(10)) were implemented on a Core2 (2.66 GHz) using the C++ programming language. The computer simulations showed that, on average, the proposed algorithm accelerated the SQRT computation by 6 times in F(p(6)), and by 10 times in F(p(10)), compared to the Tonelli-Shanks algorithm. No potential conflict of interest relevant to this article was reported.

Faculty of Engineering, Okayama University Acta Medica Okayama 1349-6115 43 2009 Predictor Order and Error Distribution of MMAE Predictors for Lossless Image Coding 93 98 EN Hirokazu Ueno Yoshitaka Morikawa 10.18926/17847 This paper investigates the relation between error distribution and predictive order of minimum mean abusolute error predictors (MMAE predictors) designed for lossless coding of grayscale images. Design of MMAE predictors reduces to the linear programming problem. Let k be the number of coefficients in a predictor (predictor order), we imagine that predictor order k may have a distribution shaping effect. Main purpose of this paper is to ensure that k has such an effect. No potential conflict of interest relevant to this article was reported.

Faculty of Engineering, Okayama University Acta Medica Okayama 1349-6115 43 2009 Human Support Agent for Design and Diagnosis using Classifier System 75 92 EN Keita Ohe Masami Konishi Jun Imai 10.18926/17844 As is well known, an advanced knowledge and know-how are needed in the design and the diagnosis work. Further, human experts can cope with the recent trend of customers needs. Therefore, the design and the diagnosis work have been privately performed in the past, and its information cannot be shared. In addition, the number of experts is decreasing. It is a very important problem to maintain and to extend experts technologies having been built up. For the purpose, methods and systems for technical inheritance of the advanced techniques of the skilled engineers are needed to train the unskilled operators and also can assist skilled operators. In this research, attention is focused on the design of analog filter circuit. To attain the target, the circuit structural classifier system to support design work is developed. Furthermore, simulation technology for hot strip rolling mills based on distributed agents is presented aimed to develop tools for the diagnosis of hot strip rolling mills operation. No potential conflict of interest relevant to this article was reported.

Faculty of Engineering, Okayama University Acta Medica Okayama 1349-6115 43 2009 Human Interface Technology for Operation Support of LargeSized Crane 61 74 EN Mao Kawamura Masami Konishi Katuki Yamagata Koichi Shimomura 10.18926/17843 In this research, a Human Interface system is designed intended to mobile crane. The intervention of human is unavoidable to attain the high performance of electro mechanical system. As is known, crane operation is complicated. Recently, the decrease of expert person induced crane accident. So in near future, it is required a partial automation of crane operation and human support technology. We are aiming at the development of the operation support system for a crane. In this research, development of the hydro mechanical models representing both of static and dynamics movements are made. Further, actual experimental data of operating mobile crane, which are electrical signal data and three-dimension (3D) position of moving load is measured. The actual operating data are compared with the model and it is found that the developed electromechanical model can explain the behaviors of actual data. No potential conflict of interest relevant to this article was reported.

Faculty of Engineering, Okayama University Acta Medica Okayama 1349-6115 43 2009 Surface Defect Inspection of a Cutting Tool by Image Processing with Neural Networks 55 60 EN Shinichiro Inoue Masami Konishi Jun Imai 10.18926/17841 In this research, an image processing method and a system for inspection support of a rod figured cutting tool are developed. As is well known, the visual inspection of a cutting tool by image processing is not easy, because cutting blade have a helical blade structure. To cope with the problem, an experimental facility with rotation and longitudinal tool shift functions to enable acquisition of blade surface pictures along a cutting rod is developed. The type of the defect treated in this paper is the spot of coating on blade surface. To judge the quality of the processed image of blade surface, neural network with autonomous learning is used. The processed image of cutting tool is divided into 64 × 64 blocks used for the input to the neural networks. Before input, each block data is preprocessed applying a edge detection filter and a transformation by the discrete fourier transform (DFT). Using these technologies, the experimental inspection system is built and tested to check the capabilities of the inspection algorithms. The diagnostic performance of the surface defect of a cutting tool was confirmed. There remained a problem to mis judge the normal tools as the defect. No potential conflict of interest relevant to this article was reported.

Faculty of Engineering, Okayama University Acta Medica Okayama 1349-6115 43 2009 Position Control of 2-Link SCARA Robot by using InternalModel Control 49 54 EN Shinya Akamatsu Masami Konishi Jun Imai 10.18926/17839 In this paper, the controlled target is the SCARA robot with two links, and the object is fine control of the arm head position of the robot. To attain the object, Internal Model Control (IMC) is introduced. A nonlinear equations are for robot dynamics formulated by solving Lagrange equation, and is linearized to design control system by IMC. The controller of IMC is designed or synthesisted as the inverse system of the linearized model, and IMC filter model is selected. Also, reference filter is introduced to make the improvement of performance. The result of control performance by IMC is compared with that of PID numerically, accuracy and incoherency are confirmed. No potential conflict of interest relevant to this article was reported.

Faculty of Engineering, Okayama University Acta Medica Okayama 1349-6115 43 2009 Positioning Control of One Link Arm with ParametricUncertainty using Quantitative Feedback Theory 39 48 EN Takayuki Kuwashima Jun Imai Masami Konishi 10.18926/17837 This paper presents method of the controller design for one link arm with parametric uncertainty. Recently, many manufacturing robots are operated in manufacturing facilities, with the aim of labor and cost saving or improvement of the productivity. Such robots need to have positioning performance of high precision. In condition that there is an uncertainty in plant dynamics, desired control performance may not be attained because the controller is designed according to the mathematical model of a plant. So it is important that the designed control system have a robust control performance. In this paper, the robust controller is designed using Quantitative Feedback Theory (QFT) for one link arm with parametric uncertainty. Simulation experiments are run for control system designed by using QFT and conventional method. The results are compared with each other and it is found that the control system designed by QFT shows a robust performance and can suppress the unevenness of output against parametric uncertainty. No potential conflict of interest relevant to this article was reported.

Faculty of Engineering, Okayama University Acta Medica Okayama 1349-6115 43 2009 Tracking Control of Combination Vehicles with PreviewFeedforward Compensation 32 38 EN Shuji Mabuchi Masami Konishi Jun Imai 10.18926/17835 A tractor-trailer vehicle in the factory might move on the route determined beforehand. However, automation of a tractor-trailer vehicle is difficult so that it is necessary to consider the nonlinearity of a vehicle and a trailer. In this research, the effective tracking control method of a tractor-trailer vehicle is proposed. The control method using time-state control form for a preview control is presented, and be applied a tractor-trailer vehicle with nonholonomic characteristics. Results of numerical experiments are presented to check effectiveness of the proposed control method. No potential conflict of interest relevant to this article was reported.

Faculty of Engineering, Okayama University Acta Medica Okayama 1349-6115 43 2009 Experimental Conditions for Observation of ThermodynamicInstability and Critical Point of Fine Particle (Dusty) Plasmas 27 31 EN Hiroo Totsuji 10.18926/17833 When the Coulomb coupling between fine particles becomes sufficiently strong in fine particle plasmas, the isothermal compressibility of the whole system diverges and we have a phase separation and an associated critical point. Experimental conditions of fine particle plasmas, densities and temperatures of components and the fine particle size, are obtained corresponding to characteristic parameters around the critical point and the dependency on ion species and other factors is discussed. No potential conflict of interest relevant to this article was reported.

Faculty of Engineering, Okayama University Acta Medica Okayama 1349-6115 43 2009 Information Transfer and Entanglement Creation by Spin Chains: Effects of Noise and Asymmetry 22 26 EN Hiroo Totsuji Chieko Totsuji Kenji Tsuruta 10.18926/17831 For the transfer of quantum information and the creation of entangled states, the application of tuned spin chains, systems of spins with the nearest-neighbor coupling tuned so as to give high efficiency, has been proposed and some examples of high performance have been given by several authors. In this article, the effect of deviations from tuned values and the effect of resultant asymmetry are investigated through numerical simulations and theoretical analyses. It is shown that there exists a system where the transfer efficiency is comparable with exactly tuned ones and, at the same time, robust to noises in the coupling constants. It is also shown that the effect of asymmetry on the efficiency of entanglement creation is of the second order when the asymmetry is small. No potential conflict of interest relevant to this article was reported.

Faculty of Engineering, Okayama University Acta Medica Okayama 1349-6115 43 2009 FDTD Simulations of Acoustic Waves in Two-DimensionalPhononic Crystals using Parallel Computer 16 21 EN Kenji Tsuruta Chieko Totsuji Hiroo Totsuji 10.18926/17829 The finite-difference time-domain (FDTD) method has been applied to the calculation of the phonon band structure of two-dimensional (2D) phononic crystals, consisting of metal cylinders placed periodically in liquid. By comparing several combinations of materials for metal cylinder and liquid, we analyze the dependence of the band structures on sound speed and density of liquid media. Moreover, the negative refraction of the acoustic waves is observed at the interfaces between phononic crystal slab and the liquid. We find that an acoustic“lens effect”with the slab appears due to the negative refractions. The relationship between the focal intensity in the lens effect and the band structure is discussed. No potential conflict of interest relevant to this article was reported.

Faculty of Engineering, Okayama University Acta Medica Okayama 1349-6115 43 2009 Dispersion Models and Electromagnetic FDTD Analyses ofNanostructured Metamaterials using Parallel Computer 8 15 EN Chieko Totsuji Kenji Tsuruta Hiroo Totsuji 10.18926/17826 Metamaterial which has negative permittivity and permeability is investigated via computer simulations. Effects of the nanostructure on dielectric and magnetic properties of the material are taken into account by introducing the Drude-Lorentz model in the materials dispersion. We include multi-band process in the dielectric response in order to reproduce accurately experimental values of bulk Au thin film. Size effect on the dispersion is examined by comparing the model with that of a noble metal particle. Based on the dispersion model constructed, we analyze the electromagnetic response of nanostructured metamaterials to evanescent waves at microwave and optical frequencies via finite-difference time-domain simulatioins on parallel computer. A re- focusing and an amplification of the evanescent waves propagating through a metamaterial, consisting of metal slab/vacuum stacking, is demonstrated for the frequencies of 30GHz and 744THz. No potential conflict of interest relevant to this article was reported.

Faculty of Engineering, Okayama University Acta Medica Okayama 1349-6115 43 2009 Crystal rotation behavior with fatigue crack propagation in copper films 1 7 EN Kenichi Shimizu Tashiyuki Torii Koki Ishida 10.18926/17822 Using a fatigue testing method by which fatigue cracks can be initiated and propagated in a film adhered to cover an elliptical through-hole in a base plate subjected to push-pull cyclic loads, annealed copper films with the thickness of 100μm and those reduced the thickness from the 100μm to 50μm by an electro-polishing were fatigued under a constant stress amplitude with a stress ratio of zero. The crystal rotation behavior with the fatigue crack propagation was investigated by measuring the crystal orientation around the fatigue crack initiated from the notch root before and after fatigue testing, using EBSD (Electron Back-scatter Diffraction) method. Then, the change of crystal orientation with fatigue testing was evaluated quantitatively from the misorientation between the crystal orientation matrix on the same point obtained before and after fatigue testing. As a result, the angle of the crystal rotation obtained from the region showing the high fatigue crack propagation rate was larger than that obtained from the region showing the low fatigue crack propagation rate for the film with the thickness of 100μm, while the fatigue crack propagated faster in the film with the thickness of 50μm than that with the thickness of 100μm regardless of the small crystal rotation angles with the fatigue testing for the film with the thickness of 50μm. No potential conflict of interest relevant to this article was reported.

岡山大学工学部 Acta Medica Okayama 0475-0071 10 1 1975 ERRATUM 61 EN 10.18926/15841 No potential conflict of interest relevant to this article was reported.

岡山大学工学部 Acta Medica Okayama 0475-0071 21 2 1987 Some Remarks on Finite Element Mesh Modeling of Crack-Tip Area 31 45 EN 10.18926/15840 The aim of this paper is to present some remarks on the arrangement of finte element mesh modeling of the area adjacent to the crack-tip which locates in two-dimensional area. Since the stress distribution near crack-tip is singular, the arrangement of mesh pattern and the selection of mesh type in the crack area govern the accuracy of the solution. This paper gives some informations on the arrangement of finite elements in the area which are obtained through numerous number of numerical experiments. And the effectivity of Zooming Technique for stress analysis is clarified through the experiments. No potential conflict of interest relevant to this article was reported.

岡山大学工学部 Acta Medica Okayama 0475-0071 21 2 1987 Car Ownership in Households 21 30 EN 10.18926/15839 Car ownership in households is analyzed by disaggregate behavioral modeling technique. Two models are built to analyze characteristic features of car ownership. The results are (1) The number of driver licenses in a household is, as a matter of course, most influencing on car ownership and multi-ownership. (2) Family size is the second most influencing. (3) Utilily obtainable by owning second or third car is higher in the household of primary industry than that of the other industry. (4) Inclination of household to be car owner is stronger in a sparsely inhabited zone than in a densely inhabited. No potential conflict of interest relevant to this article was reported.

岡山大学工学部 Acta Medica Okayama 0475-0071 21 2 1987 Influence of Sewage Treatment System on Water Quality in Kojima Lake 9 19 EN 10.18926/15838 This study dealt with the characteristics of hydrodynamics of Kojima Lake and the influence of a regional sewage treatment system in construction on the lake. Clockwise and anticlockwise circulations are caused by seasonal winds in summer and winter, respectively. The distribution of a conservative material continuously discharged off the shore of the sewage treatment plant is scarcely affected by seasonal winds and river discharges. The sewage treatment system improves the water quality of the lake except T-N. No potential conflict of interest relevant to this article was reported.

岡山大学工学部 Acta Medica Okayama 0475-0071 21 2 1987 Depth Dependency of Hardness Change of Ti-Mo Alloys 1 7 EN 10.18926/15837 We investigated the effects of resolved interstitial oxygen or nitrogen atoms and of quenched-in strain on the hardening of the single crystals grown from molten Ti-14 and 20wt pct Mo alloys. The aging treatment at 623K in atmosphere much more increased in the hardness of specimen surface than that in argon atmosphere. The quenched-in compressive stress enhanced age hardening due to omega formation. We surveyed in detail the hardness changes toward the center of plate-shaped single crystal. No potential conflict of interest relevant to this article was reported.

岡山大学工学部 Acta Medica Okayama 0475-0071 21 1 1986 Dynamic Behavior of Sand Bed around Structure under Wave Motion 81 91 EN 10.18926/15836 Under the attack of storm waves, there are many destructions of coastal structures due to scouring, sinking and sliding. These types of destructions are considered to be in close relation to the dynamic behavior of sand bed around the structures. In this study the characteristics of pore water pressure and stresses in the sand bed around a breakwater under the attack of superposed waves are treated theoretically. The results show that during the crest or the trough being in front of the structure the strength of sand bed around the structure decreases notably and the unstable zone will occur. No potential conflict of interest relevant to this article was reported.

岡山大学工学部 Acta Medica Okayama 0475-0071 21 1 1986 Determination of Coefficients of Groundwater Flow in Multilayered Aquifers 71 79 EN 10.18926/15835 It is difficult to determine the coefficients of groundwater flow from the data which were obtained from the drawdown test in a multiaquifer system. In this paper, new methods of analyzing drawdown-tests are developed and illustrated with the example to determine aquifer coefficients. In a double-layered aquifer, the analytical solution of drawdown test, in which water is discharged from both layers, is derived. And also the theoretical solution to determine the coefficient of storage by using an index of elasticity of a confined aquifer is derived. From these solutions, methods of determining the coefficient of transmissibility in a double-layered aquifer and the coefficinent of storage in a confined aquifer are got. The example analysis to determine aquifer coefficients is shown. As a result, the characteristics which were obtained by these methods are verified by the real drawdown test data. No potential conflict of interest relevant to this article was reported.

岡山大学工学部 Acta Medica Okayama 0475-0071 17 2 1983 Estimation Method of the Optimum Relaxation Factor for the Successive Overrelaxation Method 31 46 EN 10.18926/15833 New estimation method of the optimum relaxation factor for the successive overrelaxation method (SOR) is proposed, and the efficiency of the new method is surveyed through a number of numerical experiments. This method can a priori determine the value of the factor by using only the topological properties of the problem, and it is valid for a sparse set of linear equations obtained by using the five-point difference scheme for any rectangular area with arbitrary boundary conditions. The experiments clarify that the method can estimate good approximate value of the factor. No potential conflict of interest relevant to this article was reported.

岡山大学工学部 Acta Medica Okayama 0475-0071 21 1 1986 Prediction of Shrinkage and Creep of Concrete 57 70 EN 10.18926/15832 New prediction equations of shrinkage and creep of concrete are proposed, and the efficiency of the new equations are investigated through a number of experimental data. Furthermore,the characteristics and applications of the prediction equations presented in the codes of many countries are also discussed. The results showing that the new equations could estimate shrinkage and creep of concrete within a certain measure of accuracy were obtained. No potential conflict of interest relevant to this article was reported.

岡山大学工学部 Acta Medica Okayama 0475-0071 21 1 1986 Charge Density Fluctuation in Ionic Mixtures 45 55 EN 10.18926/15831 The total charge fluctuation spectrum of ionic mixtures is analyzed on the basis of the solution of the hypernetted-chain equation for the binary ionic mixtures. A simple but sufficiently accurate scaling law in the domain of intermediate coupling is obtained and the result is applied to the calculation of the bremsstrahlung emission and absorption rates in high density plasmas composed of ions of many species. No potential conflict of interest relevant to this article was reported.

岡山大学工学部 Acta Medica Okayama 0475-0071 21 1 1986 Surface Properties of Classical One-Component Plasma 31 43 EN 10.18926/15830 Surface properties of classical one-component plasma are investigated by numerical experiments on the system with periodicity in two directions perpendicular to the planar surface. The density profile, the electrostatic potential, the electric field, and the surface energy are obtained for intermediate values of the coupling parameter of bulk part r and compared with earlier experiments on spherical system. For r=10, the surface energy is almost the same as earlier result. For r =1, however, the surface energy is reduced about a factor of 2. The consistency of experimental values of the potential with the exact relation is checked and necessity of large system size is pointed out. No potential conflict of interest relevant to this article was reported.

岡山大学工学部 Acta Medica Okayama 0475-0071 21 1 1986 A Computer Program of Assembly Line Balancing Considering the Performance Rate of Each Work Station 17 30 EN 10.18926/15829 Assembly line balancing is to assign work elements to serial work stations so as to make the work content at each station as close as possible to one limiting cycle time or pitch time, i.e., an upper time limit over every station. Until now, it is usually assumed that the performance rates of work stations are constant. But in practice the performance abilities of workers, machines or robots are varied by their own working conditions. Then the actual station times are different from standard ones, and consequently the line balance may diminish in many cases. Therefore in this paper, we propose an improved balancing method, in which work elements can be assigned to the work station having the upper time limit changed by its performance rate or ability. Further we develop the computer program of the proposed method and provide an illustrative problem and computational results. In an application of our method to the practical problems, it is shown that the actual efficiency of the production line becomes near that planned. No potential conflict of interest relevant to this article was reported.

岡山大学工学部 Acta Medica Okayama 0475-0071 17 2 1983 Transmission Distance and Bit Rate in an Optical-Fiber Multi-Level PCM Transmission System 15 29 EN 10.18926/15828 Optical-fiber multi-level PCM transmission system is investigated on the transmission distance and bit rate. A communication channel is established as follows: a light signal is modulated in intensity with a completely-balanced M-Ievel code at a transmitter, and is propagated over an optical glass fiber, and is demodulated at a receiver where the signal with an additive noise is processed through a PD, an equalizing amplifier, a matched filter, (M-l) comparators and a decision circuit. The relative power of the noise from the amplifier is increased in accordance with the reciprocal of fiber's transmittance, where shot noise and thermal noise are smoothed and decreased in power by the matched filter. The relation between the BER and the SNR leads the transmission distance. The product of the transmission distance and bit rate takes the large maximum at the large values of SNR and M. The large value of M is suitable for low-speed and high-rate system, and the interference system. No potential conflict of interest relevant to this article was reported.

岡山大学工学部 Acta Medica Okayama 0475-0071 21 1 1986 Analysis of Brushless-dc Motor Drive System Taking Account of a Load 1 16 EN 10.18926/15827 In the power converter of ac drive system the switching behavior of semiconductors causes the distorted voltage and current waveforms, thus the drive characteristics are affected by them. It is, especially, an essential problem that the distorted current waveforms induce the torque ripple. It is assumed in the previous analysis that the input voltage of inverter is a ripple-free dc one. In industry, however, the input voltage of inverter is gained by rectifying the ac voltage. The torque ripple is caused by not only the behavior of inverter but also the behavior of converter. It is required to develop the analysis taking account of the both behaviors. In this paper, the analysis of brushless-dc motor drive system is proposed taking account of the ac supply, power converter, motor and load. This analytical method is the most suitable one for the analysis of practical system. The effects of factors, e.g. filter constants, inverter frequency, phase relation between ac supply and inverter cycle, load and inertia on the speed variation are revealed by this analysis. Further, the decision of filter constants is discussed from a view of speed variation. No potential conflict of interest relevant to this article was reported.

岡山大学工学部 Acta Medica Okayama 0475-0071 17 2 1983 Computer Aided Design of Thyristor Phase-Control Circuits 1 14 EN 10.18926/15826 The paper presents the computer aided design (CAD) method, the program, the design and the experimental results of inverse parallel thyristor phase control circuits. The calculated values agree well with the measured. The CAD program contains the next two methods which are inquired carefully by authors, such as (i) the optimization by SUMT (Sequential Unconstrained Minimization Technique) method, and (ii) the combined use of the gradient and the cramp calculation methods. No potential conflict of interest relevant to this article was reported.

岡山大学工学部 Acta Medica Okayama 0475-0071 20 2 1986 Two-Dimensional Automatic Mesh Generator for Finite Element Analysis 55 66 EN 10.18926/15825 In this study a new automatic mesh generator for 2- dimensional finite element analysis is proposed, and its effectivity is surveyed through a number of test examples. Proposed one is for a micro-computer, and the program is written in BASIC. The user needs no preparation for making finite element model in advance. All of the neccessary informations are displayed on CRT display and its user may answer for questions. It is expected that the cost neccessary for preparing the input-data for finite element analysis is largely decreased. No potential conflict of interest relevant to this article was reported.

岡山大学工学部 Acta Medica Okayama 0475-0071 17 1 1983 Preparation and Dielectric Properties of [Ba,Sr]TiO(3)-Al(2)O(3)-SiO(2) Glass-Ceramics 97 105 EN 10.18926/15824 A series of ferroelectric glass-ceramics was elaborated by the controlled growth of Ba(1-x)Sr(x)TiO(3) crystal particles in the glass system 60[Ba(1-y)Sr(y)]TiO(3)-10Al(2)O(3)-30SiO(2)(0≦y≦0.2) in molar basis. Analysis of crystal phases by X-ray diffraction revealed that Sr content in Ba(1-x)Sr(x)TiO(3) increased with increasing content of SrO in glasses by its preferential transfer into the crystal phase, and the appropriate temperature for the crystal growth was 1100°C. Curie temperatures of glass -ceramics shifted to lower temperature with increasing SrO content in the crystal and comparatively high dielectric constant was obtained at room temperature for a glass-ceramics with y=0.2. Frequency dependences of dielectric constant and loss tangent were examined in the frequency range from 1 K to 1 M Hz. No potential conflict of interest relevant to this article was reported.

岡山大学工学部 Acta Medica Okayama 0475-0071 20 2 1986 Inflow Control on Expressway Considering Traffic Equilibria 47 53 EN 10.18926/15823 When expressway and roads coexist, it is necessary to establish a reasonable traffic share between them. It may be practiced by the regulation of toll-rate of expressway. But at an occasional traffic congestion, the reasonable share is disturbed, so that some traffic control means should be taken. In this paper, we deal how to control inflows on expressway, from a viewpoint of the optimal share between expressway and roads. The minimization of total travel cost in a system is aimed under traffic equilibrium conditions. The problem is formed as a two-stage programming model, and a simple example solving the problem is showed. No potential conflict of interest relevant to this article was reported.

岡山大学工学部 Acta Medica Okayama 0475-0071 20 2 1986 Dynamic Behavior of Sand Bed under Oscillating Water Pressure 35 45 EN 10.18926/15822 Under the attack of storm waves, there are many destructions of coastal structures in the forms of sinking and sliding. These types of destructions will be in close relation to the dynamic behavior of sand bed around the structures. From this point of view, in this paper, we investigate the characteristics of the pore water pressure and effective stresses in the highly saturated sand bed under oscillating water pressure theoretically. The results indicate that the oscillating water pressure induce the notable drop of strength of sand bed around the structure under certain condition. No potential conflict of interest relevant to this article was reported.

岡山大学工学部 Acta Medica Okayama 0475-0071 17 1 1983 Estimation of the Number of Iterations for Detinite Convergence Condition by Use of the Gauss-Seidel Method 81 96 EN 10.18926/15821 In this investigation the estimation method of the number of iterations for definite convergence condition by use of the Gauss-Seidel method applied for a set of linear equations which is obtained from the finite element analysis (or the finite difference analysis) of any rectangular area subdivided into N*M is proposed. Though the number of iterations can be obtained by using the eigenvalue of the governing equations, the proposed method does not require the eigenvalue but only the values of Nand M. Numerical experiments on this estimation method clarify that the estimated values are within the error bound of 10%. No potential conflict of interest relevant to this article was reported.

岡山大学工学部 Acta Medica Okayama 0475-0071 17 1 1983 Optimal Toll Rate and Expansion of Urban Expressway 73 79 EN 10.18926/15820 Some extension is made of the previous papers of the same title in order to investigate (1) what aspect consumers' surplus has according to the characteristics of inverse demand curve and (2) where the maximum consumers' surplus is reached in an equilibrium of toll revenues and cost. As for (1) three kinds of inverse demand curves are assumed in general form. The marginal consumers' surplus to expansion of expressway network is proved to be of definite sign (positive or negative) or equal to zero according to each curve assumed. For each of curves, the region where consumers' surplus finds its maximum is also shown on the expressway users ~ network expansion plane. No potential conflict of interest relevant to this article was reported.

岡山大学工学部 Acta Medica Okayama 0475-0071 17 1 1983 Effect of Displacement Method on Sand Bed Liquefaction under Oscillating Water Pressure 61 71 EN 10.18926/15819 In this paper the liquefaction of sand bed under oscillating water pressure are treated as a basic study of the prevention works against the scouring around the hydraulic structures. The results of the former resurch show that the occurrence of the liquefaction depends on both properties of the oscillating water pressure and of the sand layer. Considering the latter properties, that is, the resistivity against the liquefaction increases with the increase of the permeability of the sand bed, we propose the displcement method as one of the prevention works, which is a method to displace the upper layer of the sand bed by the sand with large permeability. The effects of this method are investigated theoretically and experimentally. By the experimental study, it is shown that the proposed displacement method has the apparent effect to prevent the liquefaction. The experimental results are explained fairly well by the theoretical analysis based on the theory of the flow through the elastic porous media. No potential conflict of interest relevant to this article was reported.

岡山大学工学部 Acta Medica Okayama 0475-0071 20 2 1986 SAXS from the GP Zones in Al-4mass % Cu Alloy at Initial Stages of Ageing 21 33 EN Masuo Yamada Mutsuo Ohta Akira Sakakibara 10.18926/15818 A series of small-angle X-ray scattering photographs with monochromated and point focussed copper Ka(1) radiation was taken of a single crystal of an Al-4mass % Cu alloy at the as-quenched state from 823K and at successive stages of ageing at 313K. The crystal was so oriented that the incident direction of the radiation was along [001] axis, and was cooled with liquid nitrogen during the exposure. The pattern of the as-quenched state was homogeneous, but each of the patterns of the aged states consisted of streaks along [100] and [010] directions and a quasi-ring around the trace of the incident beam on the film (even at the shortest ageing time. l6sec). The most intense regions were found in [100], [010] , [100] and [010] directions on the ring. With the progress of the ageing the streaks and the ring became more intense and narrower. The results can be interpreted from points of view of the formation of the GP zones parallel to {100} planes ab initio, the effect of the inter-particle interference on scattering of X-rays, and the growth of the GP zones with the ageing. Guinier radius of the GP zones at each stage can be obtained from intensity change along [110], and the values are reasonably consistent with those obtained from the cross section of the streak. The presence of multi-layer zones, besides the one-layer ones, is suggested from the humps found on several intensity curves along [100] at later stages. No potential conflict of interest relevant to this article was reported.

岡山大学工学部 Acta Medica Okayama 0475-0071 17 1 1983 Off-Line Stereo Plotting by Means of Image Correlation 41 60 EN 10.18926/15817 The algorithm of automatic stereo plotting by iterative image correlation from aerial photographs and the corresponding empirical tests are described. The algorithm is oriented to off-line process, using a image scanner and a general purpose computer, and consists of 3 hierarchical correlation steps, based on one-dimensional matching using usual correlation maximum. For the correlation calculation, the FFT is effectively used. Though some defects exist in the algorithm at present, close contour plotting to middle scale maps is available except in hilly regions, in which marked features in ground covers do not exist. No potential conflict of interest relevant to this article was reported.

岡山大学工学部 Acta Medica Okayama 0475-0071 17 1 1983 Analysis of Three-Phase Thyristor Phase Control Circuit with Series RLC Elements 15 40 EN 10.18926/15816 An ac phase control circuit by thyristor is widely used in industry, The characteristics of the singlephase circuit with series RLC elements are numerically analyzed, and is reported the interesting phenomenon of step-up voltage without transformer. However, the performance of three phase phase control circuit with series RLC elements is not made clear. In this paper, the performance of three-phase control circuit of a balanced and an unbalanced load with series RLC elements is described. The analytical programs with each load are developed, and it is clarified that the calculated by this analytical program agree well with the measured. The calculated results, e.g. waveforms, RMS values of voltage and current, power, and power factor are illustrated and discussed the step-up phenomenon in three phase. No potential conflict of interest relevant to this article was reported.

岡山大学工学部 Acta Medica Okayama 0475-0071 20 2 1986 Size of Bubbles and Gas Holdup in Bubble Columns 1 20 EN 10.18926/15815 Bubble columns are extensively used in the chemical industry. This paper evaluates the present state of the art on the size of bubbles from a sieve plate and gas holdup, mainly on the basis of the results of the authors, including previous ones. The size of bubbles formed from a sieve plate has an insignificant effect of chamber volume, and gas holdup shows some different behavior, depending on the hole diameter to liquid depth. No potential conflict of interest relevant to this article was reported.

岡山大学工学部 Acta Medica Okayama 0475-0071 17 1 1983 Hydraulic Properties of Froth Layer on a Perforated Plate 1 13 EN 10.18926/15814 This paper deals with the comparison of gas-liquid holdup and froth height on a perforated plate under various operational conditions such as liquid stagnant, cocurrent, countercurrent and crosscurrent gas-liquid flow system. Tendency to foam is remarkable in countercurrent and crosscurrent flow system. The crosscurrent flow system is suitable for the operation of mass transfer from the point of view of gas-liquid holdup. No potential conflict of interest relevant to this article was reported.

岡山大学工学部 Acta Medica Okayama 0475-0071 16 2 1982 Finite Element Analysis of Salt Water Intrusion in Nonsteady Seepage 89 99 EN 10.18926/15813 In this paper are described on the finite element analysis of the nonsteady behavior of interface between salt- and freshwater in coastal groundwater. In order to investigate the validity and the accuracy of this numerical analysis solution, the results calculated by this finite element analysis have been compared with the laboratory model tests. The numerical results showed the very good agreement with the experimental data. Moreover, some applications of this analytical method have been performed. No potential conflict of interest relevant to this article was reported.

岡山大学工学部 Acta Medica Okayama 0475-0071 16 2 1982 Modifications of an Asynchronous Ring Arbiter 75 87 EN 10.18926/15812 Some modifications of an asynchronous ring arbiter are proposed. This arbiter is composed of a chain of cells. Each cell has one to one correspondence to a device. In the chain, there exists only one privilege to arbitrate conflicts of requests from many devices. A class of modifications is high speed arbiters, obtained by increasing the number of connecting wires between two adjacent cells. As the results, the time required for the privilege to pass through a cell decreases by about one-half compared with the original arbiter. Another class of modifications is arbiters with priority rules. They are obtained by adding a few hardware to the original arbiter. The priority order of request acknowledgements in all the cells is specified. Using above modifications, conflicts of requests in many digital systems may be feasibly arbitrated. No potential conflict of interest relevant to this article was reported.

岡山大学工学部 Acta Medica Okayama 0475-0071 20 1 1985 Continuous Monitoring System for the Wastewaters Having Multiply, Randomly, and Small Effluent Characteristics -Approarch to Analysis of Chemical Oxygen Demand by Complete Flow Process- 45 52 EN 10.18926/15811 A simple system was developed for the fully automatic and continuous measurement of chemical oxygen demand (COD) in wastewater samples based on colorimetry of dichromate. A sample and a solution of sulfuric acid (1+1) containing 2mM potassium dichromate are continuously pumped with a double-reciprocating micro-pump at each flow rate of 0.3 ml/min. The wastewater sample is filtered at first with a 100-mesh stainless filter and then mixed with the dichromate solution in the mixing joint. The mixture is introduced into a reaction coil made of poly(tetrafluoroethylene) tubing (1 mm i.d., 3 mm o.d., and 20 m length), being placed in an oil bath (120℃). After reaction, the mixture passes into a quartz tubular flow-through cell (10 mm path length, 18 μl volume) in a spectrophotometer, and the absorbance is measured at 445 nm. The COD value of the sample is automatically estimated from the amount of decreased absorbance. The system was successfully applied to COD measurement of some waters, and to continuous monitoring of COD in wastewater of university laboratories. The system was also evaluated by comparing with the flow injection analyzer system previously developed by the authors. No potential conflict of interest relevant to this article was reported.

岡山大学工学部 Acta Medica Okayama 0475-0071 16 2 1982 EXAFS Study on Local Structure of Iron Crystal by the Use of Asymmetrical Monochromator and PSPC 59 74 EN 10.18926/15810 The EXAFS spectroscopy equipment constructed from an asymmetrical cut flat monochromator and PSPC is applied to the structural determination of pure α-iron which has small difference (0.038nm) in the first and second nearest neighbour distance. The efficiency of the curve fitting method for the two shell model of known structure material (α-iron) is discussed, in addition to describing the details of the experimental procedure of our new type of spectrometer and of the EXAFS data analysis. No potential conflict of interest relevant to this article was reported.

岡山大学工学部 Acta Medica Okayama 0475-0071 16 2 1982 Transient Analysis of Two-Phase Induction Motor driven by Voltage Source Inverter with Current Limiter 45 58 EN 10.18926/15809 In this paper, the analysis of transient performance of two-phase induction motor driven by a voltage source inverter with current limiter is described. The motor is represented by using a two-axis model, that is, the Kron primitive machine. The state equations of mechanical-electrical system are derived. The calculation method with a discrete point of time is employed in order to decrease the CPU time of computer. The calculated results gained from this method agree well with the measured. Then, with the aid of this analytical method, the discussions on transient performance of this system are also performed. No potential conflict of interest relevant to this article was reported.

岡山大学工学部 Acta Medica Okayama 0475-0071 20 1 1985 SAXS Intensity Measurements by Photographic Methods 35 43 EN Masuo Yamada Akira Sakakibara Mutsuo Ohta 10.18926/15808 Photographic method for measurement of small-angl X-ray scattering (SAXS) is improved. Intense pointfocussing incident beam is obtained by using doubly bent crystal monochromator made of aluminium single crystal. Microphotometry and the subsequent calculation to obtain profiles, Guinier and Porod radii, integrated intensities, and so on are facilitated by using microcomputer. Integrated SAXS intensities measured from an Al-Zn alloy which has been treated under the same heat treatment conditions are coincident with one another with probable errors less than ±6 % . Ratio of the integrated intensities obtained from two Al-Zn alloys of different composition is reasonable compared with the quasi-equilibrium phase diagram. No potential conflict of interest relevant to this article was reported.

岡山大学工学部 Acta Medica Okayama 0475-0071 16 2 1982 Influence of Magnetic Saturation of Iron-Core on Performance of Thyristor Phase Control Circuit 31 43 EN 10.18926/15807 The influence of magnetic saturation of iron-core on the performance of thyristor phase control circuit with series RLC elements is described. The circuit is analyzed by applying an approximate model of three straight lines to the flux Φ vs. current i curve of the iron-core reactor. And the influence on waveforms, r.m.s. values, power factor and response are discussed. No potential conflict of interest relevant to this article was reported.

岡山大学工学部 Acta Medica Okayama 0475-0071 16 2 1982 Analysis of Thyristor Phase Control Circuit with Parallel Resonance Elements 17 29 EN 10.18926/15806 The phase control characteristics in a thyristor phase control circuit with parallel resonance elements indicate very interesting phenomenon. Several extreme values appear on the phase control curve. The phenomenon is different from the step-up one in a thyristor phase control circuit with series RLC elements which is interpreted as series resonance. To comprehend the circuit performance with those loads, it is necessary that the phenomenon on extreme value is physically clarified from other viewpoints. In this paper the performance in this circuit is studied from two viewpoints of a natural oscillation and a parallel resonance. Then, it is found that the performance depends on a natural frequency in thyristor conducting period and a parallel resonance frequency in thyristor non-conducting period. Therefore, the interesting phenomenon on extreme value is affected by the alternative of natural frequency or parallel resonance frequency. No potential conflict of interest relevant to this article was reported.

岡山大学工学部 Acta Medica Okayama 0475-0071 20 1 1985 On the Adsorptive Force in the Sucking Grasp as the Contact Surface was flat. 21 33 EN 10.18926/15805 The sucking grasp, for example, the silicon or the rubber sucker has been used widely to handle the parts in various stages of the automated process. But in order to use the sucking grasp more widely, it is necessary to develop the other type of sucking unit. In this paper, we examined the distribution of the vacuum pressure in the contact surface and estimated the adsorptive force from the vacuum pressure, the area of the contact surface, the area or the number of sucking holes, and a gap or a roughness of surface under the contact condition that the flat surface of the sucking unit sucked up the flat surface of an object. The vacuum pressure in the contact surface decreased exponentially, as the distance from the edge of the sucking hole became long. And the adsorptive force was estimated from the equation Y=1.147.P.S.(S/M)(-0.6) in the case of one sucking hole. It is necessary to consider the interaction between two sucking holes which were only separated by a very close distance to estimate the adsorptive force in case of many sucking holes. The adsorptive force became weak, as the gap No potential conflict of interest relevant to this article was reported.

岡山大学工学部 Acta Medica Okayama 0475-0071 16 2 1982 A Least-Squares Method for Unfolding Convolution Products in X-ray Diffraction Line Profiles 1 16 EN 10.18926/15804 A deconvolution method for the X-ray diffraction line profile is proposed, which is based on the conventional least-squares method. The true profile is assumed to be a functional form. The numerical values of parameters of the function assumed are determined so that the calculated profile, which is a convolution of the function and the instrumental profile, has a minimum deviation from the observed one. The method is illustrated by analysis of the X-ray powder diffraction profile of sodium chloride 222 reflexion under the assumption that the true profile is a Gaussian or a Cauchy function. No potential conflict of interest relevant to this article was reported.

岡山大学工学部 Acta Medica Okayama 0475-0071 16 1 1982 Bandwidth Minimization Algorithm for Finite Element Mesh 147 159 EN 10.18926/15803 Renumbering algorithms commonly in use for the band solver are generally applicable for any kind of linear equations, and, therefore, we may say that they cann't effectively utilize the characteristics of the finite element mesh. In this paper we investigate the characteristics of the finite element mesh systems, and introduce them into Taniguchi-Shiraishi Algorithm which already introduced some properties of FEM mesh systems. And through several numerical experiments it is proved that this improved algorithm is one of the fastest one. No potential conflict of interest relevant to this article was reported.

岡山大学工学部 Acta Medica Okayama 0475-0071 16 1 1982 System Dynamics Model on Urban Growth with an Application to Okayama City 125 145 EN 10.18926/15801 A system dynamics model to forecast future movements of a city was studied. The model consists of three sections of population sector, industry sector, land use sector and some divisions of labor, income employment, housing land which connect each sections. Economic growth rate, public investment program, housing land supply program were incorporated in the model as political variables. The model was applied to Okayama city for thirty years from 1975 to 2005. The results of the simulation are summarized as follows: 1) The drift of peoples into Okayama city will advance in the future. 2) Tertiary industries will be given much weight as compared with secondary industries. 3) Because of the drift of peoples, housing problems will be serious in the future. No potential conflict of interest relevant to this article was reported.

岡山大学工学部 Acta Medica Okayama 0475-0071 19 2 1985 Galerkin Method to an Integral Equation in the Kinetic Theory 49 61 EN 10.18926/15800 A Galerkin method is applied to a singular integral equation of fredholm type originated in the problem of the rarefied gas flow over a plane wall. The solution is expanded in a series of the Abramowitz function. The numerical calculations were carried out up to ten-terms expansions. The results show a good convergence of the series.The comparison is made with the previous work obtained by the moment method. No potential conflict of interest relevant to this article was reported.

岡山大学工学部 Acta Medica Okayama 0475-0071 16 1 1982 Optimal Toll Rate and Expansion of Urban Expressway 105 123 EN 10.18926/15799 A welfare economic approach is tried to an optimal decision of toll rate and expansion of urban expressway network in an equilibrium of toll revenues and cost of service supplied. The model, originated with Yamada, is such that the decision comes into optimality when the maximum consumers' surplus is reached in the equilibrium condition. The paper is concerned with some general aspects of the optimal solution and reexamination of the solution obtained in the past when used a specific demand curve. General aspects obtained are as follows; The extremum condition to consumers' surplus is equivalent to that to diverted traffic (the realized number of expressway users) only when demand curve has such a property that the marginal consumers' surplus to network expansion vanishes. In case that the marginal consumers' surplus does not vanish, the extrema of consumers' surplus is found in the regions of negative marginal diverted traffic if demand curve yields positive marginal surplus, and in the regions of the positive if it gives negative marginal surplus. The contact points of demand and average cost curves give extrema of neither consumers' surplus nor diverted traffic. An implicative finding, made out by Yamada by using a specific demand curve, that optimal network expansion is reached when the marginal service cost to expansion averaged to the marginal diverted traffic to expansion is equal to the value of time saved by using expressway just by mean trip length holds good at the points of the maximum diverted traffic, but not at the contacts of demand and average cost curves. In case of the demand curve, the condition for an equilibrium of revenues and cost to come into existence is that the minimum of the ratio of service cost averaged to the whole population of expressway users to the value of time mentioned above is less than or equal to e(-1). No potential conflict of interest relevant to this article was reported.

岡山大学工学部 Acta Medica Okayama 0475-0071 19 2 1985 A Consideration on Convergence Condition of Explicit Finite Element Analysis for Heat Transfer Equation 33 48 EN 10.18926/15798 This paper treats the convergence condition of the explicit finite element method (i.e. the time and spatial axes are discretized by using the explicit finite difference method and the weighted residual method, respectively) which is applied for analyzing the heat problem in region with complex boundary configuration and also with several material properties. The main role of this study is the application of the Brauer's theorem. As the results we obtain that the usage of the Brauer's theorem is valid and that the application method of the theorem is presented in this paper. No potential conflict of interest relevant to this article was reported.

岡山大学工学部 Acta Medica Okayama 0475-0071 16 1 1982 Liquefaction of Highly Saturated Sand Layer under Oscillating Water Pressure 91 104 EN 10.18926/15797 In this paper the vertical distribution of pore water pressure in the highly saturated sand layer under the oscillating water pressure are treated theoretically and experimentally. By the experiments it is shown that the water pressure acting on the sand surface propagates into the sand layer with the damping in amplitude and the lag in phase, and that the liquefaction, the state that the effective stress becomes zero, occurs under certain conditions. These experimental results are explained fairly well by the same theoretical treatment as for the ground water problems in the elastic aquifer. The main characteristics of liquefaction clarified by the analysis are as follows. 1) The depth of the liquified layer increases with the increase of the amplitude and the frequency of the oscillating water pressure. 2) The increase of the volume of the water and the air in the layer increases the liquified depth. Especially the very small amount of the air affects the liquefaction significantly. 3) The liquified depth decrease rapidly with the increase of the compressibility coefficient of the sand. 4) In the range beyond a certain value of the permeability coefficient the liquified depth decrease with the increase of the coefficient. No potential conflict of interest relevant to this article was reported.

岡山大学工学部 Acta Medica Okayama 0475-0071 19 2 1985 Optimal Pricing in Urban Expressway 23 32 EN 10.18926/15796 A welfare economic approach is applied to investigate some implications of optimal pricing in urban expressway where two different groups of users are supposed to exist. On the assumption of a specified demand function, following implications are shown; (1) optimal prices must be such that the diversion ratios are the same and (2) the price rates must be set equal each other, where the price rate means the proportion of the price to the average user benefit. In connection with the results, the elasticity of the demand with respect to price is measured in Osaka area of Hanshin Expressway, where two different levels of price are flatly set for users according to the characteristics of their cars. No potential conflict of interest relevant to this article was reported.

岡山大学工学部 Acta Medica Okayama 0475-0071 16 1 1982 Determination of Diffusion and Dispersion Parameters for Flow in Porous Media 65 89 EN 10.18926/15795 The purposes of this research is an investigation of the intrusion of sea water into coastal aquifers. For this subject, this paper deals with proposing rational methods of getting diffusion coefficient and dispersion parameter for flow in porous media in a laboratory. These parameters of soil are indispensable in order to apply an analytical approach or a numerical approach to actual salt water intrusion problems. Experimental apparatuses were constructed and test procedures were also developed to measure concentration behaviors in a saturated porous media by using electro conductivity probe. As the results, the diffusion coefficients for the Toyoura standard sand and the Asahi river sand determined by two methods, that is, "Boltzman's transformation method" and "Instantaneous profile analysis method". The longitudinal coefficient of dispersion for one-dimensional flow was also determined by the least squares curve fitting method with a function of a certain range of seepage velocity. No potential conflict of interest relevant to this article was reported.

岡山大学工学部 Acta Medica Okayama 0475-0071 19 2 1985 Quasi-random Scanning of a Digitally Controlled Spectrometry 13 22 EN Ryuji Koga Megumi Kosaka Hiroya Sano 10.18926/15794 A quasi-random method for spectral scanning is proposed to reduce an alias response to a quick change in the source abundance. A direct application is made for an atmospheric methane monitoring with a current-tunable diode laser. Only barrel shift methods are examined being found further vulnerable to drifting etalon fringes. No potential conflict of interest relevant to this article was reported.

岡山大学工学部 Acta Medica Okayama 0475-0071 16 1 1982 Rectification of Digitized Aerial Photographic Image 47 64 EN 10.18926/15793 A practical example of digital rectification of tilted photographs using a drum scanning micro densitometer and general purpose computers is depicted. The present research covers rectification of projective distorsions, occuring when the camera axis is not truly vertical, and affine distorsions due to curvature of a drum of a scanner. For this purpose, fundamental mathematical expressions were derived. And some pixel interpolation methods necessary for image reconstruction were compared experimentally. The examples revealed, however, that the film was deformed so complexly that they could not be corrected sufficiently only by affine transformation. Accuracy of rectification was checked by use of stereo aerial photographs in terms of residual y-parallaxes. The result showed residual y-parallaxes of ± 1 pixel (± 50 μm) and sometimes ± 2 pixels were observed. They seem to be caused mainly by film deformations which have not been eliminated, and their amount seems to exceed the photogrammetric tolerance. No potential conflict of interest relevant to this article was reported.

岡山大学工学部 Acta Medica Okayama 0475-0071 19 2 1985 Order-Disorder Transition in Urea-Polyethylene Complex 1 11 EN 10.18926/15792 The phase transition of urea complexes whose guest components range from n-paraffin to polyethylene was investigated by DSC thermal analysis. The transition temperatures increased with increasing the chain length; the related heats did not change much with the chain length. An X-ray powder diffractometry for urea-polyethylene complex revealed that the complex undergoes the same kind of phase transition between orthorhombic and hexagonal as urea-n-paraffin complex. The transition is interpreted in terms of an order-disorder transition with respect to the orientation of the guest molecule. No potential conflict of interest relevant to this article was reported.

岡山大学工学部 Acta Medica Okayama 0475-0071 16 1 1982 A Unified Approach to System Data Handling in CAD System for Designing Control Systems 31 45 EN 10.18926/15791 System data handling in CAD sY8tem for designing control systems is discussed. A man-oriented data description method for a wide sense block diagram and its automatical transformation into the state space description is proposed. This work is a part of CAD system: CADPACS-T which has been under development for designing control systems in our laboratory. The proposal data description for a wide sense block diagram has the following features: 1) to correspond nicety to the block diagram and to be suitable for a man-oriented expression, 2) to express even a large scale system compactly by partitioning into some subsystems defined externally, 3) to be easy to add /or alter the input-output terminals, parameters or elements, and 4) to need not to assign the connection relationship explicitly owing to adopting the input-output terminal/line names. Moreover, system data handling in designing the PI controller for an actual boiler system expressed in a block diagram is taken up as an example. No potential conflict of interest relevant to this article was reported.

岡山大学工学部 Acta Medica Okayama 0475-0071 16 1 1982 Improvement of Etalon-fringe Immunity in Diode-laser Derivative Spectroscopy 21 30 EN Ryuji Koga Megumi Kosaka Hiroya Sano 10.18926/15790 In a sensitive spectrometry with lead-salt diode lasers, etalon-fringe phenomena often intervene in the measured absorption spectrum. Derivative methods are employed for the purpose of high resolution where the pertaining wavelength is modulated. This paper presents results of mathematical examination on a possible improvement of immunity from the etalon-fringes by choosing the profile of the wavelength modulation. No potential conflict of interest relevant to this article was reported.

岡山大学工学部 Acta Medica Okayama 0475-0071 19 1 1984 Evaluation of Three Flow Injection Analysis Methods for the Determination of Chemical Oxygen Demand 53 62 EN 10.18926/15789 Three methods for determining chemical oxygen demand (COD) by means of flow injection analysis (FIA) with potassium permanganate, potassium dichromate, or cerium(IV) sulfate as oxidant, developed in this laboratory, are described from the point of view of their operating properties. The permanganate method is the most sensitive and common, but forms manganese(IV) oxide precipitate which blocks the FIA lines and connectors. Addition of phosphoric acid in the reagent system is, however, effective to some extent in order to avoid blocking the flow system. The dichromate method is the most workable and stable, but produces toxic wastes containing chromium(VI). The cerium method is the most probable because cerium(IV) is the strongest oxidant of the three and less poisonous. The last method with cerium(IV) sulfate is therefore recommendable to apply to the continuous monitoring of COD in many situation. No potential conflict of interest relevant to this article was reported.

岡山大学工学部 Acta Medica Okayama 0475-0071 19 1 1984 Preparation and Dielectric Properties of [Ba, Ca] TiO(3)-Al(2)O(3)-SiO(2) Glass-Ceramics 45 51 EN 10.18926/15787 Succeeding to 60(Ba,Sr)TiO(3)-10A1(2)O(3)-30SiO(2)glassceramics reported in our previous paper, another type of ferroelectric glass-ceramics was elaborated by the controlled growth of Ba(l-x)Ca(x)TiO(3) crystal particles in the glass system 60 (Ba(l-y)Ca(y)) TiO(3)-10Al(2)O(3)-30SiO(2) (0.0<y<0.25) in molar basis. Analysis of crystal phases by X-ray diffraction revealed that Ca content in the crystal phase of Ba(l-x)Ca(x)TiO(3) increased with increasing amount of CaO in glass up to y=0.125, and the composition of Ba(l-x)Ca(x)TiO(3) solid solution was restricted by x=0.225. Curie points(Tc) of the present glasscceramics were independent of the composition of Ba(l-x)Ca(x)TiO(3), however temperature coefficients of Σ were lowered by the addition of increasing amount of CaO. Frequency dependencies of dielectric constant and loss tangent were examined in the frequency range from 1 k to 1 M Hz. No potential conflict of interest relevant to this article was reported.

岡山大学工学部 Acta Medica Okayama 0475-0071 15 2 1981 Some Theoretical Aspects on Optimal Toll-Rate and Scale of Urban Expressway 165 185 EN 10.18926/15786 In this paper, the optimal toll-rate and scale of urban expressway is discussed economically. The criterion used is the total surplus of expressway, which is defined as the sum of consumer's surplus of expressway users and producer's surplus on the side of expressway administrator. The total surplus is equivalent to the difference of the value of total saved travel times of expressway users and the total cost required to construct and administrate expressway systems. The flow-dependent travel times is assumed, and traffic demand is induced through equilibrium method. On the other hand, for the management of expressway to be capable, the accounting condition that the fare revenue must repay the total cost should be satisfied. Under this accounting condition, the optimal rate and scale which maximize the total surplus are requested, and their properties are examined. The analysis is practiced for both caces of flowindependent cost function and flow-dependent cost function. One remarkable result is that the maximum feasible scale under the accounting condition does not privide a maximum for total surplus. No potential conflict of interest relevant to this article was reported.

岡山大学工学部 Acta Medica Okayama 0475-0071 19 1 1984 Error Analysis of Band Matrix Method 33 44 EN 10.18926/15785 Numerical error in the solution of the band matrix method based on the elimination method in single precision is investigated theoretically and experimentally, and the behaviour of the truncation error and the roundoff error is clarified. Some important suggestions for the useful application of the band solver are proposed by using the results of above error analysis. No potential conflict of interest relevant to this article was reported.

岡山大学工学部 Acta Medica Okayama 0475-0071 15 2 1981 Hydraulics and Water Quality in Kojima Bay 147 164 EN 10.18926/15784 In this paper, characteristics of hydraulics and water quality in Kojima Bay are discussed based on field observations. The main results obtained are as follows. (1) The variation of flow rate in Kojima Bay has periods for 30 minutes to 2 hours. This characteristic is represented by a two-dimensional numerical simulation fairly well. (2) The local distributions of salinity and suspended solids show increase in the direction to the mouth of Kojima Bay. On the other hand, the distribution of COD(Mn) is nearly uniform in the whole area of the bay. Salinity appears to be influenced by river discharge sensitively but suspended solids does not. (3) The vertical distributions of salinity and suspended solids are similar. There are similar points between the cross-sectional average of water quality and surface water quality. (4) The surface water quality seems to be influenced by the variation of velocity. No potential conflict of interest relevant to this article was reported.

岡山大学工学部 Acta Medica Okayama 0475-0071 19 1 1984 Pore Water Pressure in Sand Bed under Oscillating Water Pressure 13 32 EN 10.18926/15783 In this paper the theoretical method to analyse the pore water pressures in the sand bed under the oscillating water pressure is developed. In the former researchs the validity of the theoretical treatment for the one-dimensional problem has been verified. However, the one-dimensional treatment is not sufficient to obtain the precise informations concerning the many practical problems. From this point of view, in this study, we derive the fundamental equations for the general three-dimensional sand layer under the oscillating water pressure. The validity of this theoretical method is verified by experiments for the twodimensional problems. No potential conflict of interest relevant to this article was reported.

岡山大学工学部 Acta Medica Okayama 0475-0071 15 2 1981 Dissection Method for a Regular Finite Element Mesh 133 146 EN 10.18926/15782 From the theoretical approach to the fill-in minimization problem we present one of the optimal vertex elimination process for a regular finite element mesh M (nxn), and through a number of numerical experiments it is verified that the new process model can always lead to better numerical results comparing to other methods presently in use. Since the process here presented cann't give the actual dissections of M but can clarify how the optimal elimination is, the process includes George's Nested Dissection Method and the method by Duff, Erisman and Reid. By this investigation we can conclude that l) the concept of "Dissection" is neccessary for minimizing the number of fill-ins, 2) the location of the dissection lines can be systematically decided even if n of M is odd or even number, and though the interior area of M is dissected as George's Method, the surrounding area of M is rather irregularily dissected, and 3) the model of the vertex elimination process given in this paper is applied to other kind of regular finite element mesh or finite difference mesh, too. No potential conflict of interest relevant to this article was reported.

岡山大学工学部 Acta Medica Okayama 0475-0071 19 1 1984 On the Bremsstranlung in High-Density Plasmas 1 12 EN 10.18926/15781 Emission and absorption coefficients of bremsstrahlung by high-temperature partially degenerate electrons are calculated for high-density plasmas where Coulomb coupling between ions is not weak. It is shown that the ion correlation substantially reduces these coefficients. No potential conflict of interest relevant to this article was reported.

岡山大学工学部 Acta Medica Okayama 0475-0071 15 2 1981 A General Purpose Simulator for Multivariable Control Systems 119 132 EN 10.18926/15780 A high speed and high accuracy simulator whose data-handling is light and whose weak stability is assured even for stiff systems is discussed. This work is a part of CAD package : CADPACS-T which has been under development for the purpose of designing control systems utilizing TSS of a large scale digital computer in our laboratory. This simulator realizes high accuracy, high computational speed and high reliability adopting A-stable extrapolation methods to transform into a difference system, a recursive formula of an output interval to solve the difference equation, automatic choice of an optimal step length such that minimizes an predicted error, and evaluating error bounds closely near the actual errors in the point of numerical calculation. Moreover, in the point of data management, this realizes separation of program modules from data, common utilization of data and separation of investigation from simulation. No potential conflict of interest relevant to this article was reported.

岡山大学工学部 Acta Medica Okayama 0475-0071 15 2 1981 Dynamical Fluctuation Spectra of Two-Dimensional ClassicalElectron Liquids 107 118 EN 10.18926/15779 The dynamic form factor and the transverse part of the fluctuation spectrum of momentum density are analysed on the basis of the generalized Langevin equation. According to the indication of the result, numerical experiments are extended and it is shown that the transverse fluctuation spectrum contains two kinds of excitations. The frequency moment sum rules are discussed in relation to one of these excitations. No potential conflict of interest relevant to this article was reported.

岡山大学工学部 Acta Medica Okayama 0475-0071 18 1 1984 Convergence Condition of Explicit Finite Element Method for Heat Transfer Problem 111 130 EN 10.18926/15778 The convergence condition of the explicit difference method for the heat transfer problem is aiready obtained. On the other hand, if the problem is formulated by using the weighted residual method for spatial axis, we have no tool to estimate the critical timestep width. In this paper, the estimation method is theoretically presented, and its propriety is examined through a number of numerical experiments. No potential conflict of interest relevant to this article was reported.

岡山大学工学部 Acta Medica Okayama 0475-0071 15 2 1981 Lower Bounds for Correlation Energy of Mixtures of Charged Hard Spheres 93 106 EN 10.18926/15777 A method to obtain exact lower bounds for the correlation energy of one-component plasmas is extended to neutral mixtures of charged hard spheres. Upper bounds for the correlation functions of charge densities are derived. These upper bounds, the semi-positivity of correlation functions, and that of the charge-densityfluctuation spectrum are used to improve upon the known bound due to Onsager. No potential conflict of interest relevant to this article was reported.

岡山大学工学部 Acta Medica Okayama 0475-0071 15 2 1981 Accuracy and Etalon Fringe Phenomena in Methane-gas Spectrometry Employing Tunable Diode Lasers 79 92 EN Ryuji Koga Satoru Nagase Megumi Kosaka Hiroya Sano 10.18926/15776 A method to monitor atmospheric gas concentration employing a tunable diode laser is proposed. An apparatus was built and experiments were made. The tunable diode laser employed was of'PbSnTe with its wavenumber about 1200 cm(-1) at a temperature of 77 K. Methane concentration in laboratory atmosphere was measured on the experiments. The inquired gas-density is obtained by a hardwired microcomputer incorporating the measured absorption spectrum over a prescribed range instead of an absorption at a single wavenumber. By this, drift type noises are suppressed. After an analysis based on experimental data, an attainable sensitivity for methane was found to be 1 ppb.m. This value may increase if an etalon fringe interference exists. The natural concentration, about 1 ppm, of atmospheric methane was actually measured with a short optical path of only one meter. No potential conflict of interest relevant to this article was reported.

岡山大学工学部 Acta Medica Okayama 0475-0071 18 1 1984 Some Statistical Considerations on Window Width and Matching Stability of Images. 101 110 EN 10.18926/15775 In stereo matching of images, sample cross-covariances are used commonly as a criterion for deciding whether matched points are truly conjugate. Hereupon window width is a serious parameters to dominate matching stability. This paper argues about relation of matching stability with window width in terms of statistical behavior of sample covariances. For simple circumstances of analysis auto-covariances of a single image are considered instead of cross-covariances of stereo ones. First the mean and variance of sample auto-covariances are derived with parameters, window width and positional lag. Secondly they are evaluated from the correlation function estimated on an aerial image under the assumption of ergodicity to observe how they vary according as two parameters vary. From this result a variation factor is proved usefull to estimate appropriate window width. No potential conflict of interest relevant to this article was reported.

岡山大学工学部 Acta Medica Okayama 0475-0071 18 1 1984 Optical Circuit for Waveform-synthesis with Utilizing both GaAs- and Si-Optoelectronic Switches 91 100 EN Hiroya Sano Ryuji Koga Megumi Kosaka Ichiro Wake 10.18926/15774 This paper presents an optical-waveform synthesizer as one of the applications of optical bistable devices. This device is advantageous in terms of faster operation in which width of each pulse obtained is down to the order of subnanosecond, because this device employs both GaAs- and Si-optoelectronic switches as photodetector. Optical pulse shaping as a preliminary experiment is also described. No potential conflict of interest relevant to this article was reported.

岡山大学工学部 Acta Medica Okayama 0475-0071 15 2 1981 Smoothing of Impulse Noise by Orthogonal Transform 69 77 EN 10.18926/15773 Electromagnetic impulse noise which is harmful to signal measurement or transmission of information, is smoothed by the orthogonal transform processor. The idealized impulse noise with infinitesimal duration and Gaussianly-distributed amplitude shows the same spectral characteristics as white Gaussian noise. Optimal correlation detector against such noise is easily realized by the orthogonal transform processor. Photoelectric pulse signals disturbed by the impulse noise from the power supply can be well detected through the Walsh waveform analyzer. Also, orthogonally-synthesized signals can be demodulated with firmly-suppressed impulse noise, where both the statistical and instantaneous SNRs are superior to those in the usual PCM transmission system. No potential conflict of interest relevant to this article was reported.

岡山大学工学部 Acta Medica Okayama 0475-0071 15 2 1981 New Approach to Short-Range Ordering in GP(2) Zones in Al-3.82wt. % Cu Alloy 55 67 EN 10.18926/15772 X-ray diffuse scatteing intensity measurement has been carried out for the Al-3,82% Cu single crystal in which GP (2) zones are found. The two dimensional equiintensity contour maps in h(1) h(2) 0 plane are obtained from surveying around several reflections. The diffuse intensity around 2 1 0 reflection, which shows a cross like streak, is carefully examined. Warren-Cowley short-range order parameters, a(i), are estimated from the diffuse intensities around 2 1 0 reflection. The component of the intensities coming from atomic displacements was subtracted from the total diffuse intensity. It is found that the equi-intensity contours after the correction of the atomic displacements shows an anisotropic distribution and the GP(2) zone is an ellipsoid with a modified layer structure. No potential conflict of interest relevant to this article was reported.

岡山大学工学部 Acta Medica Okayama 0475-0071 18 1 1984 Electrochemistry of Redox Reaction III. On the Kinetic Equations for Chronoamperometry 75 89 EN 10.18926/15771 A basic kinetic equation of potential-step chronoamperometric current-time curve controlled by the rates of diffusion and electron transfer for a simple one-electron charge transfer reaction was given and various features of current-time curves were deduced from a theoretical treatment. The current-time equations for reversible and irreversible electron transfer processes appear as special cases with limited conditions of the equation reported in the present paper. And a potential-step chronoamperometric method to determine kinetic parameters from a current-time curve was proposed therefrom. The extension of a basic kinetic equation to more general multistep charge-transfer process was also considered. No potential conflict of interest relevant to this article was reported.

岡山大学工学部 Acta Medica Okayama 0475-0071 15 2 1981 On the Formation and Growth of G.P. zones in Al-Zn Alloys above or below the Spinodal Temperature 29 53 EN Mutsuo Ohta Teruto Kanadani Akira Sakakibara Masuo Yamada 10.18926/15770 Measurements of electrical resistivity and intensity of small-angle X-ray scattering and transmission electron microscopy were made on Al-Zn alloys of several compositions. G.P. zones are formed by the nucleation-and-growth mechanism above the spinodal temperature. The nucleus has a critical size for growth. This size becomes larger when aged at higher temperatures. The sizes of the G.P. zones formed by this mechanism distribute broadly, but those formed by the spinodal decomposition do closely. The spinodal temperatures estimated for Al-10.0, 12.5, 15.0, and 20.0wt % Zn alloys are ~95, ~110, ~130, and ~180℃, respectively. The critical temperatures below which G.P. zones are observed in these alloys are ~115, ~135, ~160, and ~210℃, respectively. No potential conflict of interest relevant to this article was reported.

岡山大学工学部 Acta Medica Okayama 0475-0071 15 2 1981 Computer Program of Line Balancing under the Multiple Workers in Each Station (LBMW) 21 28 EN 10.18926/15769 An assembly line with no paralleling of work elements and work stations is called a serial line. The cycle time of the serial line must be at least equal to the maximum work element time. To lower the cycle time beyond the limit and increase the production rate, one may permit the paralleling of work elements or work stations. So in this paper we propose the parallel assignment method for achieving a higher production rate. In this method, work elements are assigned to work stations under the multiple upper time limits which are the products of the various numbers of workers and the limiting cycle time. Further we develop the computer program of the proposed method and provide an illustrative problem and computational results. No potential conflict of interest relevant to this article was reported.

岡山大学工学部 Acta Medica Okayama 0475-0071 18 1 1984 Electrochemistry of Redox Reaction II. On the Kinetic Equations for Chronopotentiometry 57 73 EN 10.18926/15768 Basic kinetic equations of chronopotentiometric potential-time curves, in which the equations for reversible, quasi-reversible and irreversible electron transfer process appeared in special cases, were given and a chronopotentiometric method for determining kinetic parameters was proposed therefrom. The method was demonstrated for Fe(3+)/Fe(2+) redox reaction in acidic aqueous media. The limitations of the method and the double-layer charging effects on the potential-time curve were discussed. The extension of the method to more general electrode processes was also considered. No potential conflict of interest relevant to this article was reported.

岡山大学工学部 Acta Medica Okayama 0475-0071 18 1 1984 Electrochemistry of Redox Reaction I. On the Kinetic Equations for Rotating Disk Technique 43 56 EN 10.18926/15767 An equation on the current-polarization voltage characteristics of single charge transfer redox reaction on a rotating disk electrode (RDE) was given and a curvefitting method to determine kinetic parameters from an observed polarization curve was proposed therefrom. The method was demonstrated for Fe(2+)/Fe(3+)redox reaction in acidic aqueous electrolyte on Pt-RDE and the limitation of the method was discussed. The extension of the method to multistep charge transfer reaction was also considered. No potential conflict of interest relevant to this article was reported.

岡山大学工学部 Acta Medica Okayama 0475-0071 15 2 1981 Generalized Analytical Program of Thyristor Phase Control Circuit with Series and Parallel Resonance Load 1 19 EN 10.18926/15766 The systematic analytical method is reqUired for the ac phase control circuit by means of an inverse parallel thyristor pair which has a series and parallel L-C resonant load, because the phase control action causes abnormal and interesting phenomena, such as an extreme increase of voltage and current, an unique increase and decrease of contained higher harmonics, and a wide variation of power factor, etc. In this paper, the program for the analysis of the thyristor phase control circuit with a series and parallel connected load of series R-L-C circuit units, is been developed. By means of the program, the transient and steady state characteristics of the circuit can be calculated and then comparative study of various versions of circuits can be carried out systematically. The usefulness of the program is demonstrated by some numerical calculated examples. No potential conflict of interest relevant to this article was reported.

岡山大学工学部 Acta Medica Okayama 0475-0071 15 1 1980 Improved Method for the Flow Injection Analysis of Chemical Oxygen Demand Using Silver Nitrate 111 121 EN 10.18926/15765 On the flow injection analysis (FIA) of chemical oxygen demand (COD), silver salt was added as an oxidation catalyst for COD substances and a masking agent for halide to improve operating conditions of the FIA apparatus. Both of a proper concentration of potassium permanganate solution and 6.0 % sulfuric acid solution containing 0.1 % silver nitrate are individually pumped up with respective flow rates of 0.51 ml min(-l) and merged into a carrier stream. A 20 μ1 of sample solution is injected into the flow of sulfuric acid solution at just before the merging place. The sample mixed with the carrier solutions in a reaction manifol(polytetrafluoroethylene tubing: 0.5 mm i.d. x 30 m), is passed through a thermostated bath at 100 °c and led to a flow cell for the absorbance measurements at 525 nm. The absorbances are continuously recorded with time. The peaks in the recordings showed good reproducibility and the calibration obtained at a linear concentration range of 0 - 170 mg 1(-1) COD with glucose as standard. The detection limit and precision confirmed with this method were 5 mg 1(-1) and 0.8 %, respectively. Chloride ion up to 200 mg 1(-1) did not interfere without elimination of a silver chloride precipitate. By the present FIA method, several industrial waste water samples were analyzed at a sampling rate of about 40 samples per hour, and their apparent COD values were compared with those found by the manual JIS method. Both of the methods gave the similar results within an error range from -35 to +5 %. No potential conflict of interest relevant to this article was reported.

岡山大学工学部 Acta Medica Okayama 0475-0071 18 1 1984 The Apparatus to Measure the Multi-point Critical Flicker Fusion Frequency (MCFF) 33 42 EN 10.18926/15764 In this paper, we mentioned the apparatus developed to measure CFFs at the various point of the retina. Eleven CFFs measured at the central retina of both eyes (used usually} simultaneously, at the central retina of each eye separately, and at four points of the peripheral retina of each eye were analyzed together and referred to as the multi-point critical flicker fusion frequency (MCFF) . MCFF can be used to estimate the level of cortex activity, since the temporal and nasal parts of each eye are connected to different visual cortexes through the optic nerve. As the apparatus used to measure the MCFF was controlled by a micro-computer, the order of measurements and the calculation were done automatically. No potential conflict of interest relevant to this article was reported.

岡山大学工学部 Acta Medica Okayama 0475-0071 15 1 1980 Fundamental Study of the Fill-in Minimization Problem 101 110 EN 10.18926/15763 In this paper the fill-in minimization problem which arises at the application of the sparse matrix method for a large sparse set of linear equations is discussed from the graph-theoretic viewpoint and also through the numerical experiments. Therefore, this investigation consists of two parts, and in the former part the author shows, at first, that the elimination process of a sparse matrix is equivalently replaced to the vertex eliminations for a graph obtained from the matrix, and by use of some concepts in the theory of graph he proves that the vertex elimination process for the minimum fill-in is equivalent to the vertex eliminations for vertices in each subgraph which is obtained by the appropriate dissection of whole graph, and that there are only two types of vertex eliminations through the process. This results in the proposal of a new model of the vertex elimination process. The latter part of this investigation is used for the verification of the results from the theoretic investigation. Through the numerical experiments he concludes that the new model of the vertex elimination process is valid, at least, for a graph like a regular finite element mesh. Furthermore, he shows that this model coincides with Nested Dissection Method which can give the minimum value of fill-in, at present. No potential conflict of interest relevant to this article was reported.

岡山大学工学部 Acta Medica Okayama 0475-0071 18 1 1984 Finite Element Analysis of Transformer Cores 1 31 EN 10.18926/15762 The quantitative analysis of localized flux distributions in transformer cores has become easy through the progress of numerical field calculations. In this paper, the effects of core constructions, joint configurations, magnetizing characteristics of materials on the flux distributions are examined using newly developed techniques such as a gap element, an approximate method for solving three-dimensional magnetic fields, the time periodicity finite element method, an efficient technique for treating hysteresis characteristics and so on. A method for the optimum design of transformer cores is also discussed. Main results obtained can be summarized as follows: (a) The building factor of the core made of higely-oriented silicon steel is larger than that of the conventional core. (b) The iron losses at joints are much affected by overlap lengths, number of laminations per stagger layer and a small irregularity of the arrangement of sheets. (c) It is clarified that examinations of the optimum construction of core and the most desirable magnetic characteristics of core material are possible using the finite element method. No potential conflict of interest relevant to this article was reported.

岡山大学工学部 Acta Medica Okayama 0475-0071 15 1 1980 Variational Formulations for Electromagnetic Field and Charged-Particle Stream Configurations and Their Linearization 79 100 EN Yoshitaka Morikawa Hiroshi Hamada 10.18926/15761 Two variational formulations for electromagnetic field and charged-particle stream configurations, in which both field and particles are described by the field-like variables suited for the problems of electrodynamics, are presented. One of them is directly obtained through slight modifications of Sturrock's original procedure but has a complicated form. The other is obtained through linearization of the preceding one and has a compact form. Both formulations lend themselves to straightforward derivation of the well-known energy-momentum tensor and/or its conservation law. Specifically the latter one is of academic interest because of its compact form. Moreover, as a proof of its practical usefulness the variational principle under the small-amplitude approximation is derived from it, which is known to provide a basis for the study of certain types of instability in plasmas. It is, however, hoped that it will find main applications in the electrodynamics problems concerned with large-amplitude behavior. No potential conflict of interest relevant to this article was reported.

岡山大学工学部 Acta Medica Okayama 0475-0071 15 1 1980 Quantum-corrected Hybrid Bohm and Classical Diffusion in a Laser-driven Plasma 61 78 EN 10.18926/15759 Within the framework of the hydrodynamic guidingcenter approximation, we have investigated such quantum effects as the diffraction correction and the symmetry effect on the classical version of the particle diffusion coefficient D(1) across a dc magnetic field through the temperature-dependent pseudo-potentials. Analytic results are explicitly given with recourse to the order-of-magnitude estimate of a set of parameters pertaining to a laser-driven plasma. No potential conflict of interest relevant to this article was reported.

岡山大学工学部 Acta Medica Okayama 0475-0071 15 1 1980 Fast Spectrometry System with Using Tunable Laser Diode 47 60 EN Ryuji Koga Satoru Nagase Megumi Kosaka Hiroya Sano 10.18926/15756 Basic prohlems are discussed about a local, realtime and very sensitive air-pollution monitoring using a laser diode. The method employs the second derivative spectrometry replacing the incoherent light source and mechanical choppers in a traditional method with the laser diode and a newly developed electronic system. Etalon fringes at this system becomes the dominant noise source and its statistic and dynamical features are to be understood. Numerical examination was done for the optimal width of optical frequency modulation. A very fast measurement of weak absorption spectra became possible by the development of lock-in-amplifiers with finite integration time instead of a low-pass filter. Spectra of methane in 7.6 μm region and a time-dependent spectrum of the etaIon fringe are shown. No potential conflict of interest relevant to this article was reported.

岡山大学工学部 Acta Medica Okayama 0475-0071 15 1 1980 Hardware Design of Digital System with Remote-DiagnosticCapability 29 45 EN 10.18926/15754 In this paper, a hardware design of digital systems with remote-diagnostic capability is presented. We consider a method for testing a system T(l) on a module basis with a remotely installed systems T(2). In the testing mode, we set up a system (T(l)-m,m') such that a module m of T(l) is replaced by an adapter A(1) connected to other adapter A(2) through a telephone line and the corresponding module m' of T(2) is connected to A(2). If the system (T(l)-m,m') can simulate T(1) in the absence of any faluts, then it can test m' under a self test program. The main subject of this paper is to study the conditions of the system to be testable in the above sense. At first, the remote diagnostic network based on the system in this paper, restrictions to the system configuration required to perform such a diagnosis and the operation of the diagnostic system are described. The second, the module structure to make above simulation possible is considered, representing the system configuration graphically. Finally, an example of the adapter is shown and the time consumed to diagnose is discussed. One of our results is that a sufficiently large class of synchronous digital systems with few minor conventions is testable. No potential conflict of interest relevant to this article was reported.

岡山大学工学部 Acta Medica Okayama 0475-0071 15 1 1980 Influences of the Skin Impedance as the Interface in Bioelectric Potential Measurement 17 28 EN 10.18926/15753 In the case of non-invasive measurement of bioelectric potential from body surface, the influence of the skin impedance has been investigated by using strict equivalent circuits of skin impedances. The relationship between the characteristic of skin impedance and the wave distortion was made clear. Furthermore, in the case of electrocardiograph, the shift potential of indifferent electrode to standard potential was obtained by means of simulation, and the distortions caused by connective resistances of a central terminal and skin impedance were quantitatively explained. No potential conflict of interest relevant to this article was reported.

岡山大学工学部 Acta Medica Okayama 0475-0071 14 2 1980 Semiautomated Determination of COD in Environmental Water Samples 119 129 EN 10.18926/15752 A new method based on the principle of flow injection analysis is presented for the semiautomated determination of chemical oxygen demand (COD) in environmental water samples. The method is rapid and continuous, and suitable for the monitoring of COD in wastewaters. The apparatus used was simply constructed by parts commercially available for high performance liquid chromatography. Teflon tubing heated with a boiling water was used as a reactor and simultaneously used for mixing coils and transmission lines. The operating conditions were examined to apply the determination of COD in wastewaters by using glucose as a standard COD substance. The procedures recommended are as follows: Both 4.9x10(-4) M potassium permanganate and 6.7 % sulfuric acid solutions are individually pumped, 20 μl of a sample solution is injected into the flow of the sulfuric acid solution, and then mixed with a mixing joint. The mixed solution is transported to a flow cell situated in a spectrophotometer fixed at a wavelength of 525 nm, and decrements of absorbance are recorded. The peaks were reproducibly obtained at a concentration range of 10 - 200 mg-COD 1(-1). Chloride up to 1000 mg 1(-1) was not interfered at all. Various wastewater samples were analyzed by the proposed method at a sampling rate of 30 samples per hour, and the apparent COD values obtained were compared with the manual COD ones obtained by JIS method. No potential conflict of interest relevant to this article was reported.

岡山大学工学部 Acta Medica Okayama 0475-0071 15 1 1980 Factors Affecting Plunge Grinding Force 1 16 EN Toshikatsu Nakajima Yoshiyuki Uno 10.18926/15751 Grinding force has a close relation to grinding inputs such as grinding wheel, work material, interference condition, grinding speed, grinding fluid and machine condition, and therefore varies widely with grinding inputs. On the other hand, grinding force affects significantly grinding outputs which are efficiency and quality evaluated with surface roughness, accuracy, surface integrity and so on. It is important to make clear the relations between grinding inputs and grinding force in order to control grinding outputs. In this paper, from the above point of view, the relations between grinding inputs and grinding force are experimentally investigated. It is pointed out that the normal grinding force, the tangential grinding force and its ratio are determined by the product of speed ratio of work speed to wheel speed and setting depth of cut as for interference conditions, and by the product of square of dressing feed and cutting depth of. dresser as for dressing conditions. Furthermore as for characteristics of work materials, the normal grinding force has a close relation to the yield stress, and the force ratio is related to the elongation of work material. No potential conflict of interest relevant to this article was reported.

岡山大学工学部 Acta Medica Okayama 0475-0071 14 2 1980 Properties of the Amorphous Fe(100-x)B(x) Alloy Prepared by rf-Sputtering Technique 111 118 EN 10.18926/15750 The amorphous Fe(100-x)B(x) alloys with 18 ≤ x ≤ 42 were prepared by applying a rf-sputtering technique. The chemical composition of the sputtered films was well controlled by varying the area ratio of B plate to Fe plate, which were used as a composite target. The crystallization temperature of the amorphous films linearly rises with increasing of B content up to x = 36, but falls in a composition range of 36 ≤ x ≤ 42. The amorphous Fe(100-x)B(x) films exhibited ferromagnetism in the whole compositions studied in the present work. The internal magnetic field of the amorphous films decreases with increasing of B content, since the charge transfer increases with B atom in the system Fe(100-x)B(x). No potential conflict of interest relevant to this article was reported.

岡山大学工学部 Acta Medica Okayama 0475-0071 14 2 1980 Experimental Study on Determining Unsaturated Property of Soil 73 110 EN 10.18926/15749 This paper deals with the experimental study of hydraulic properties of unsaturated soil. In treating unsaturated zone, a great deal more data are required than are required for the saturated zone, but these properties of soils must be known to apply the finite element approach to actual groundwater flow problems. The purposes of this paper are to propose a rational basis of getting experimental relationships between prossure head() and hydraulic conductivity(K) and between pressure head() and volumetric moisture content(θ) with "the instantaneous profile method" in a laboratory. An apparatus was constructed and test procedures were developed to measure pressure head and volumetric moisture content by using pressure transducers and low-energy gamma ray attenuation. The technique of a low-energy gamma radiation apparatus does provide a means for accurate measurement of water content without disturbing the system into which water is moving. Furthermore rapid measurement of water content becomes possible at any position in a soil so that water content changes with time may easily be followed. The tensiometer~transducer system provides a most valuable means of measuring pressure head with rapid response and with provision of a complete record of the pressure head changes with time. No potential conflict of interest relevant to this article was reported.

岡山大学工学部 Acta Medica Okayama 0475-0071 14 2 1980 A Consideration on Physics of Saturated-UnsaturatedGroundwater Motion 53 72 EN 10.18926/15748 The purposes of this paper are primarily to research on behavior of groundwater flow in saturated and unsaturated zone, and to present the fundamentals of the theory of groundwater flow. This paper discusses the physics of the saturated-unsaturated groundwater motion. Evaluations confirm the early belief that Darcy's law is of the nature of statistical result giving the empirical equivalent of Navier-Stokes equations. The governing equation of saturated-unsaturated flow in porous media is derived from the law of mass conservation and from the Darcy's law and Richard's equation of motion and is compared with the Klute's diffusion equation which has been widely used in the analysis of unsaturated flow. As a result; it is concluded that the governing equation has the advantage that can be applied for the whole flow region. Typical boundary conditions are enumerated. No potential conflict of interest relevant to this article was reported.

岡山大学工学部 Acta Medica Okayama 0475-0071 14 1 1979 Ozonation of Organic Substances from View Points of Wastewater Treatment 139 150 EN 10.18926/15747 In this paper, ozonation of organic substances which are found in wastewater is discussed regarding following respects; (1)removal ratios of COD(Cr) and TOC, (2)removal properties, and (3)oxidation products. The main results are summarized as follows. (l)Ozonation quickly removes proteins and amino acids, but mildly polysaccharides and n-saturated carboxylic acids. (2)The initial removal of COD(Cr) or TOC is quite rapid, but, as the reaction continues, it slows down so drasti-cally that one may suspect that it has completed. (3)Starch and albumine are decomposed to the smaller molecular compounds. (4)The COD(Cr) /TOC ratio of each substance which is chosen in this study decreases. This means that ozonation results in the formation of oxygenated fragments of the original molecule-occurs by bond fission or partial oxidation. (5)Proteins are indispensable components in frothing because they are surface active. They are removed by not only oxidation but also foaming, however, the removal by foaming is not so large. No potential conflict of interest relevant to this article was reported.

岡山大学工学部 Acta Medica Okayama 0475-0071 14 1 1979 Discharge Coeffi cient of a Sluice Gate Placed at Sudden Expansion of Open Channel 127 138 EN 10.18926/15746 In this paper the discharge coefficient of a sluice gate placed at the sudden expansion of an open channel is investigated theoretically and experimentally. Lateral and vertical expansions are treated in the study. The coefficients obtained for channels with sudden expansion are compared with those for the straight channel. For free efflux, experimental results show that the coeffcients for expanded channels are always larger than those for a straiaht one,and that the coefficient for a channel to be fully expanded to both lateral and vertical directions takes about 1.2 times larger value than that for a straight one. For submerged efflux, the coefficient is obtained theoretically by using the efflux model shown in this study. The theoretical results explain the experimental ones fairly well. The coefficient for lateral expansion is always smaller than that for a straight channel. The minimum downstream water depth required to submerged efflux for the expanded channels becomes smaller than that for a straight channel. No potential conflict of interest relevant to this article was reported.

岡山大学工学部 Acta Medica Okayama 0475-0071 14 2 1980 System Identification Using Fast Fourier Transform 33 51 EN 10.18926/15745 Algorithms for system identification applying throughout Fast Fourier Transform (FFT) to the major calculating operations are introduced. It is shown that by using data of about as twice length as system settling time and by truncating the incorrect correlation functions resulting from them, errors owing to finiteness of data can be avoided. It is shown that so as to suppress the effects owing to statistical fluctuation of input data or output noise, superposition of data in frequency domain is effective, and also the damping terms of poles or zeros can be efficiently evaluated by utilizing the phase change of the spectra of the impulse response sequence. The proposed method can be efficiently applied to relatively higher order systems or relatively rapidly time-variant systems because of high accuracy and high speed processing of FFT. Moreover, it needs not to assume the order of the system a priori, and yields a reasonable lower order approximating system in itself. No potential conflict of interest relevant to this article was reported.

岡山大学工学部 Acta Medica Okayama 0475-0071 14 1 1979 Transient Flow in Groundwater to Wells in Island Model Aquifer 95 126 EN 10.18926/15744 In order to apply the numerical method to practical groundwater flow problem in the field, the hydraulic properties must be estimated. In this paper, new methods of analyzing drawdown tests were developed and illustrated with some examples to determine hydraulic properties of aquifer. Drawdown tests sometimes have to be performed near the boundary of the aquifer or in the much groundwater supplied aquifer. In such instances, the assumption that the aquifer is of infinite areal extent is no longer valid. Therefore the analytical solutions of unsteady flow due to drawdown test are derived in the conception of "Island Model" that the shape of groundwater level is fixed by the circular water supply which is equilibrium with the pumping rate. By using these solutions, new methods of analyzing drawdown tests which are performed in a confined aquifer and an unconfined aquifer were given respectively and the effect of influence region was evaluated. The example analysis to determine permeability and storage coefficient were shown. As the results,the propriety of the solutions is verified comparing the analytical results with the drawdown test data taken from a real aquifer project. No potential conflict of interest relevant to this article was reported.

岡山大学工学部 Acta Medica Okayama 0475-0071 14 2 1980 Microcomputer Filtering System to Measure Very Small Transmission Loss of Impulsive Signals 23 31 EN 10.18926/15743 This paper describes a method for measuring very small transmission loss of impulsive signals. The correlative fluctuations within input and output signals are eliminated effectively by the analog simultaneous differencer. The difference and normal signals are alternately sampled and accumulated by the digitizer and the microcomputer, that is, the microcomputer 2-channels box-car integrator is realized. The difference and normal accumulated data are transferred to the personal computer, which calculates the ratio of the difference to normal accumulated data, i.e. the estimated attenuation in nepers. By the experiments of electrical and optical impulse transmissions, the minimum measurable attenuations become respectively 2.7×10(-4)NP and 6.0×10(-4)Np. Even the latter value is the smallest so far as the authors know. No potential conflict of interest relevant to this article was reported.

岡山大学工学部 Acta Medica Okayama 0475-0071 14 1 1979 Application of Fininite Element Analysis to Groundwater Flow in Field Problems 61 94 EN 10.18926/15742 The purposes of this paper are primarily to research on behavior of groundwater flow in saturated and unsaturated zone and to develop the most effective methods for solving groundwater flow problems related to civil engineering practice. The mathematical model provides a finite element solution to two- or threedimensional problems involving transient flow in the saturated and unsaturated domains of nonhomogeneous, anisotropic porous media. Before progressing into the various levels of applications the input data and boundary conditions are discussed and evaluated. To demonstrate the flexibility of the finite element approach and its capability in treating complex situations which are often encountered in the field, the groundwater flow through sand bank at flood water levels and the flow through aquifer due to an excavation were analyzed. As the results there were good qualitative agreements between the numerical results and the informations received. No potential conflict of interest relevant to this article was reported.

岡山大学工学部 Acta Medica Okayama 0475-0071 14 2 1980 A High-powered Optoelectronic Switch with Picosecond Risetime 13 22 EN Ryuji Koga Masami Ebara Megumi Kosaka Hiroya Sano 10.18926/15741 A switch element has been developed so that a kilovolt step voltage should be supplied to a 50Ω transmission line with a subnanosecond rise time. The element is of silicon substrate with high purity and a pair of electrodes is attached by the evaporation process. The switch action is performed by the photoconductivity produced by the laser light pulse. This paper deals with a preliminary analysis, manufacturing processes and experimental results of the optoelectronic switch. A performance of 320V output with less than 4 ns risetime was obtained with sufficient persistence for more than 2×10(5) pulse shots. This switch was successfully applied to an optical waveform monitor for laser light pulses giving a resolution less than 2 ns. No potential conflict of interest relevant to this article was reported.

岡山大学工学部 Acta Medica Okayama 0475-0071 14 1 1979 Absorption Spectrum Measurement for Atmospheric Level Nitric Monoxide in γ-0 Band and Its Density Deduction 55 60 EN Ryuji Koga Keiji Hirao Megumi Kosaka Hiroya Sano 10.18926/15740 An absorption spectrum of γ-0 band of nitric monoxide of very dilute density was taken. An experimental electronic device showed a distinguishing power of 0.01 ppm through 10 m optical pathlength. By the aid of a data processing based on a principle developed by the authors, this sensitivity does not suffer from coexisting sulfur dioxide, which shares the absorption band with the nitric monoxide. No potential conflict of interest relevant to this article was reported.

岡山大学工学部 Acta Medica Okayama 0475-0071 14 1 1979 Behaviors of a Soliton in Nonlinear L-C Lines with Abrupt Parameter Change 39 53 EN Shigeji Nogi Kiyoshi Fukui 10.18926/15739 Some behaviors of a lattice soliton in nonlinear L-C ladder lines with abrupt parameter change are investigated. The results of computer and circuit experiments show that in the case of a soliton incident upon the line of larger characteristic impedance and of higher phase velocity in linearized-line-limit, the transmitted wave evolves into larger number of solitons. The experimental results can be well explained by use of both linearization approximation for the line near the junction and the theory by Gardner, Greene, Kruskal and Miura. No potential conflict of interest relevant to this article was reported.

岡山大学工学部 Acta Medica Okayama 0475-0071 14 1 1979 Dynamic Switching of Wall-Reattachment Fluidic Device 29 37 EN 10.18926/15738 Effect of the geometrical configuration of wall-reattachment fluidic device on the switching dynamics, the switching time, and its dispersion, was investigated experimentally by using a large scale model. The results obtained can be summarized as follows: 1) The switching time, its dispersion, and switching probability depend upon the connection of the input to the control port. 2) Effect of the vent and splitter on the jet in dynamic switching is explained commonly by using the margin of a given control flow rate to the switching control flow rate. 3) The switching time ,decreases as input increases, whereas its dispersion remains constant except for small input. No potential conflict of interest relevant to this article was reported.

岡山大学工学部 Acta Medica Okayama 0475-0071 14 2 1980 The Analysis of Vocational Aptitude Changing with Age 1 12 EN 10.18926/15737 The assumption that vocational aptitude changed with age and with the kind of occupation was examined from the tendency of the fitted curve for the score of the aptitude test. 9 vocational aptitudes were measured by the general vocational aptitude test by Japan Labor Ministry. Subjects were 382 male workers (design engineers, turners, welders, can manufacturing workers, and crane operators) of from 20 to 59 years old, and 348 male and female students (junior high school, vocational school, and university) of from 15 to 19 years old. The design engineers' aptitudes advanced along the quadratic curve until 31 years old, but almost all the aptitudes of the other workers fell along the linear curve with age. The design engineers preserved various aptitudes until 52 years old, the turners 44, and the welders, the can manufacturing workers, and the crane operators 37. The students' aptitudes were equal to those of the workers of from 15 to 25 years old. The workers preserved Spatial aptitude and Numerical aptitude until 45 years old. This could be said in all the occupations here. Further it was made clear from the micromotion study that the influence of age was caused by therbligs No potential conflict of interest relevant to this article was reported.

岡山大学工学部 Acta Medica Okayama 0475-0071 14 1 1979 Iron Losses of Silicon Steel due to Rotating Fluxes (Inclined Rotating Flux and Distorted One) 15 28 EN 10.18926/15736 Characteristics of iron losses in silicon steel due to inclined rotating fluxes and distorted ones are described. Iron losses due to rotating fluxes have been measured at various conditions for grain-oriented and non-oriented silicon steels by using an improved thermistor-bridge method. Loss measurements indicate that the iron loss due to the inclined rotating flux is greater than that due to the non-inclined one. However, the iron loss due to the distorted rotating flux is not always greater than that due to the non-distorted one. No potential conflict of interest relevant to this article was reported.

岡山大学工学部 Acta Medica Okayama 0475-0071 14 1 1979 Oriented Crystallization of Polyethylene at High Pressure from Flowed Melt 9 14 EN 10.18926/15735 In the course of the study of polymer crystallization at high pressure, oriented crystallization of extended chain crystals of polyethylene were examined. Molten polyethylene were extruded into a die at a few hundred atm, and follwed by crystallization by high pressure application above 3000 atm. Resulting sample shows chain orientation to extruded direction. Thick lamella nearly a few thousand angstrom, which are typical feature of high pressure crystallization, were observed to be stacked parallel each other. In spite of favorable condition for crystals to grow to chain direction, remarkable growth to normal direction to them were also observed. No potential conflict of interest relevant to this article was reported.

岡山大学工学部 Acta Medica Okayama 0475-0071 14 1 1979 The Molecular Mechanism of Chain Tilt in Poly (ethylene terephthalate) Fibers 1 7 EN 10.18926/15734 The molecular mechanism of chain tilt in poly(ethylene terephthalate) (PET) fibers was proposed. The mechanism was considered basing on the ordering process from the cold drawn state of glassy PET. It was confirmed that the direction of maximum contraction on ordering agrees with the azimuth of chain tilt which varies with annealing temperature. In the stacking structure of irregular folded chain blocks of cold drawn PET, the expansion to the chain direction and the contraction to the lateral direction yield the compressive stress and tensile stress r respectively. The stress revealed as the result of the ordering from the glassy structure to crystalline structure can be relaxed by the rotation of the resulting crystallites. Therefore, we can suggest that the chain tilt is caused by the relaxation process of the stress. No potential conflict of interest relevant to this article was reported.

岡山大学工学部 Acta Medica Okayama 0475-0071 12 1978 A Statistical Analysis of Traffic Accidents in Minor Street Network 129 139 EN 10.18926/15733 A statistical analysis is applied to find what states of "block" are dangerous from view point of traffic accident. Here, the block is defined to be an area surrounded by some major streets and is feeded by a minor street network. The accidents under study are those which occur in the whole minor street network. They are grouped into three kinds; pedestrian, vehicle and the gross accidents. And each is classified to three types according to the place where the accident occurs. At the beginning 22 variables are assumed to state a certain relationship of some states of the block with the occurrences of accidents and 12 variables are found significant finally through factor analysis. Further examination has reached several key variables that migth have something significant to cause traffic accidents in the block. The key ones are the number of lanes of street and the number of legs of intersection, especially nearly 2 lanes street and 3-leg intersection, respectively. The case study was carried out on 26 blocks sampled from Osaka City. No potential conflict of interest relevant to this article was reported.

岡山大学工学部 Acta Medica Okayama 0475-0071 13 1979 Asymptotic Theory of Rayleigh Problem in Rarefied Gas 249 258 EN 10.18926/15732 The asymptotic theory of Rayleigh shear flow for large values of time is developed on the basis of the linearized Boltzmann-Krook equation. Asymptotic equations for mean velocity outside the Knudsen layer are obtained by employing the Hilbert expansion. Slip boundary conditions are derived from the analysis of the Knudsen layer adjacent to the wall. A solution of the asymptotic equation is obtained under the slip boundary condition and zero initial condition. Discussions are also made of the flow induced by a slowly oscillating flat plate. No potential conflict of interest relevant to this article was reported.

岡山大学工学部 Acta Medica Okayama 0475-0071 12 1978 Analysis of Pump Test Data for Partial Penetrating wells 97 128 EN 10.18926/15731 The solutions of unsteady phreatic flow toward a partially penetrating well in an aquifer of finite thickness are described. Firstly the solution for a confined aquifer is shown. In this case,three methods of analyzing field data with partially penetrating well are given, that is, "Log-Log Method, Log-Log Distance Drawdown Method and Jacob's Method Ajusted for Partial Penetration". By using these methods the hydraulic conductivities and the specific storage of the aquifer may be determined. Secondly the solution for an,unconfined aquifer is shown. In this case, also two methods of analyzing field data with partially penetrating well are given. By using these methods, the anisotropic permeability and the storage coefficient (effective porosity) of the aquifer may be determined. Moreover in each case, the effects of partial penetration are discussed and the limits of adapting the Theis' and Jacob's methods are setted. From these analytic results, some cosiderations are added to determine the anisotropy of permeability and to evaluate the storage coefficient. No potential conflict of interest relevant to this article was reported.

岡山大学工学部 Acta Medica Okayama 0475-0071 12 1978 Cluster Expansion for Two-Dimensional Electron Liquids 89 96 EN 10.18926/15730 The pair correlation function and the correlation energy density of two-dimensional electron liquids are calculated on the basis of the Salpeter's Debye-chain type expansion. When the two-dimensional plasma parameter (￡=2πne4T-2) is small, the expansion to the first order gives the correlation energy to the order of (￡21n￡). It is shown that experimental results in the domain (￡<0.5) can be reproduced by taking into account the first and the second order terms in this expansion. No potential conflict of interest relevant to this article was reported.

岡山大学工学部 Acta Medica Okayama 0475-0071 13 1979 A GRAPH-THEORETIC STUDY OF THE MINIMUM FILL-IN PROBLEM FOR SPARSE MATRIX METHOD 239 248 EN 10.18926/15729 In this paper the minimum fill-in problem which arises at the application of the sparse matrix method for linear sparse systems is discussed from the graphtheoretic viewpoint and the author gives some results which can be directly introduced in the design of, so called, the optimal elimination ordering algorithm which gives the minimum fill-in(the number of zeros in coefficient matrix which become non-zero during the elimination process). Through this investigation only graphs are treated instead of the coefficient matrices for linear systems, and the elimination process for a matrix is equivalated to the vertx eliminations for the graph. Then, the results by the theoretical investigation are summarized as following: 1. Optimal elimination for each subgraph which is subdivided appropriately from whole graph leads to the global optimum. 2. In each subgraph there are only two kind of eliminations. Furthermore, some numerical experiments show the characteristics of the subset of vertices, which subdivide a subgraph from the residual. No potential conflict of interest relevant to this article was reported.

岡山大学工学部 Acta Medica Okayama 0475-0071 13 1979 An Adaptive Observer via Optimal Control Law 225 238 EN 10.18926/15728 This paper deals with the adaptive observer which estimates the states and parameters of unknown system. It is shown that the adaptive observer problem is reduced to the identification of the transformation matrix for an arbitrary designable observer. Moreover, the adaptive process of the unknown parameters is reduced to the linear optimal regulator problem. As the result, a new method is presented to obtain an appropriate adaptive process with good insight. And, in this identification, a linear filter is found to be also useful against noises in input-output data. To achieve high accuracy, a particular nonlinear filtering can improve SN ratio only in the direction of the unknown vector. Even if SN ratio of input-output data has zero dB, sufficient accuracy can be accomplished within suitable correction time. This design algorithm seems to be rather straightforward and practical. Since input sequence is required to be only sufficiently general, the method is applicable to on-line identification also. No potential conflict of interest relevant to this article was reported.

岡山大学工学部 Acta Medica Okayama 0475-0071 12 1978 On the Apparent Activation Energy for Clustering in Dilute Al-Zn Alloys 77 88 EN Mutsuo Ohta Toshinori Kobayashi Akira Sakakibara 10.18926/15727 The clustering phenomenon was observed when dilute Al-Zn alloys were annealed at temperatures higher than the solvus of the G.P.zones. In this report the apparent activation energy for clustering is estimated and compared with the experimental results. The estimated value of the apparent activation energy for clustering in several Al-Zn alloys comes to 0.51 eV, which is larger than the effective migration energy 0.43 eV of Zn atoms in Al-Zn alloys. No potential conflict of interest relevant to this article was reported.

岡山大学工学部 Acta Medica Okayama 0475-0071 13 1979 Longitudinal Properties of Two-Dimensional Classical Electron Liquids 219 224 EN 10.18926/15726 The dynamic form factor and the dispersion relation of the plasma oscillation of two-dimensional classical systems of electrons with ordinary Coulomb interaction are obtained by numerical experiments in the domain of the plasma parameter 2.24≤√=(πn)(1/2)e(2)/T≤70.7, where n, e, and T are the areal number density, the electronic charge, and the temperature in energy units, respectively. No potential conflict of interest relevant to this article was reported.

岡山大学工学部 Acta Medica Okayama 0475-0071 12 1978 Fluctuation of the Solute Concentration in Al Rich Al-Zn Alloys 59 75 EN Mutsuo Ohta Teruto Kanadani Akira Sakakibara 10.18926/15725 Several Al-Zn alloys containing 0.041-4.4 at % Zn were studied by means of measurements of electrical resistivity. The results obtained are as follows : (1) The electrical resistivity increases when the specimen is annealed at temperatures higher than the solvus temperature of the G.P. zones. The increase of the resistivity is due to the formation of fluctuation. (2) The electrical resistivity of the specimen containing fluctuation is dependent upon annealing temperature only and independent of quenching temperature. (3) The fluctuation is formed in very dilute alloys as 0.041 at % Zn at temperatures higher than the solvus temperature of the G.P. zones. (4) The formation energy of vacancy and the migration energy of the Zn atom in the alloys determined by the formation process of fluctuation are in good agreement with those by the formation process of G.P. zones. (5) In spite of the result (4), it seems that the fluctuation is not the same as the small G.P. zones which are observed in the early stage of aging. No potential conflict of interest relevant to this article was reported.

岡山大学工学部 Acta Medica Okayama 0475-0071 13 1979 Lower Bounds for Thermodynmnic Quantities of Classical Ionic Mixtures 209 218 EN 10.18926/15724 Exact lower bounds are given for thermodynamic quantities of ionic mixtures in the uniform background in d dimensions with three-dimensional (1/r) Coulomb interaction (d=2 and 3) and with d-dimensional Coulomb interaction (d=1, 2, and 3). It is shown that these lower bounds improve upon known ones and give values close to experimental results which are available in the case of d=3. No potential conflict of interest relevant to this article was reported.

岡山大学工学部 Acta Medica Okayama 0475-0071 13 1979 A Performance Analysis For An Air-Pollution Monitoring Using A Pulsed Dye Laser 195 207 EN Hiroya Sano Ryuji Koga Megumi Kosaka 10.18926/15723 The maximally attainable accuracy of an airpollution monitoring system is investigated. The system is composed of a tunable pulsed dye laser as the light source, photodiodes as the opto-electric converter and a low noise electronic signal processor specifically designed by the authors. The extreme value of the accuracy is given in terms of the standard deviation of the attenuation. The value is 3.4×10(-4)[Nep√(pulse number)] for an averaged value for multiple laser shots. Also the wavelength reproduceability of a dye laser was examined, which resulted in that a computer should take a part in the wavelength control in order that this method should be feasible. No potential conflict of interest relevant to this article was reported.

岡山大学工学部 Acta Medica Okayama 0475-0071 13 1979 A Notion of Adjoint Spectrum in the Application to Air-pollution Monitoring 181 193 EN Hiroya Sano Ryuji Koga Yoshihiro Tanada Megumi Kosaka 10.18926/15722 This report deals with a notion of adjoint spectrum which is applicable to air-pollution monitoring by using pulsed lasers. Both Raman and absorption spectra of multiple gas complex are linear combinations of the spectra, each of which is specific to a gas species and its magnitude is proportional to the density. An extended formulation of the method of least squares is made in terms of a new notion, adjoint spectra, which visualizes the structure of the numerical filter. Applications of the derived numerical filters to the two methods are shown and features are described about the synthesized filters. No potential conflict of interest relevant to this article was reported.

岡山大学工学部 Acta Medica Okayama 0475-0071 12 1978 A Driving Method of a Spuare Waveform Inverter Circuit Using Power Transistors 53 58 EN 10.18926/15721 In recent years, the development of a high power transistor element is proceeding. A high power inverter circuit using power transistors are finding a good number of applications in induction heating and melting. Turn off time of power transistors occupies 5-lOμs of switching characteristics. A driving method to give base inputs for a half period is widely used for a inverter circuit. But this method has the following defects, the short-circuit current flows through two transistors because the other pair transistors turn on before one pair transistors turn off. So the switching loss is increased, the maximum output and the efficiency are decreased. In this paper, a driving method to give base inputs for the less period as compared with a half period is discussed. Using this method, the foregoing defects is lost and the driving frequency is able to become higher. In addition, it become clear that the square waveform output is given using this method in the case of R-L load. No potential conflict of interest relevant to this article was reported.

岡山大学工学部 Acta Medica Okayama 0475-0071 12 1978 Behavior of Transistor Switching in AC Chopper Circuit 45 52 EN 10.18926/15720 In this paper, an AC chopper circuit, using a power transistor, is described which chops the AC voltage with a commercial frequency. The circuit is composed of a diode bridge and a power transistor in series with a load and capable of adjusting the switching frequency, fc, and the time ratio, T=ton/(ton+toff). The switching frequency and the time ratio of the AC chopper circuit depend on switching-times, that is, delay time, rise time, carrier storage time and fall time, especially in the high frequency. The upper limit of the switching frequency (about 150kHz) and the output characteristics of the circuit are investigated. No potential conflict of interest relevant to this article was reported.

岡山大学工学部 Acta Medica Okayama 0475-0071 13 1979 A Walsh Waoofonn Analyzer and Its Applications to Filtering of Pulse Signals 163 180 EN 10.18926/15719 A new waveform analyzer based on the Walsh transform　is developed and is applied to a real-time filtering of fast pulse signals, and the linear filterings　of time signals through the Walsh transform is　discussed. The analyzer converts a solitary waveform during 16 μs into the 16 Walsh amplitude spectra in a hybrid manner: it has the sequency band from 62.5 kzps to 500 kzps. The spectra are parallelly held during 16 μs by analog integrators, while serially displayed by the CRT, and one of them is digitally read out. The spectra of the test waves are measured within the error rate of several per cent. The analyzer is applied to the correlative detection of the photoelectric pulse signals in a gasspectroscopic system using a pulse laser, and there composes the matched filter, which is useful for measuring the signals superposed by Gaussian noises with a high accuracy. For the real-time filtering of fast signals, the arithmetic convolution and the frequency power spectra are approximated using the complex Walsh transform. These approximations are of practical use in 16 or 32 dimensions. Then, the matched filters for pulse peaking are given by the approximate convolution and by the dyadic convolution. No potential conflict of interest relevant to this article was reported.

岡山大学工学部 Acta Medica Okayama 0475-0071 13 1979 Coupling-Network Dependence of Locking Phenomena in Microwave Oscillators 153 162 EN Kiyoshi Fukui Shigeji Nogi Masuo Yamada Akira Sakakibara 10.18926/15717 A unified treatment of injection and mutual phase locking phenomena in microwave oscillators coupled by a network characterized by a Y-matrix is presented. Under certain simplifying assumptions, steady state solutions such as locking frequency and oscillation phase relation are given with emphasis placed on the coupling-network dependence of locking bandwidth. Also, some examples of locking system specified by y(21)=0, Y(21)= Y(12) and y21= -Y12 are briefly discussed. No potential conflict of interest relevant to this article was reported.

岡山大学工学部 Acta Medica Okayama 0475-0071 12 1978 Parameters for Analysis on Distributed Circuit Properties of Etched Alunimum Oxide Film 29 36 EN 10.18926/15716 The distributed circuit properties based on pores in the etched aluminum oxide film of the electrolytic capacitor have been analysed by the mathematical equation. This paper proposes the selection and the determining method of the parameters appearing in the analysis. No potential conflict of interest relevant to this article was reported.

岡山大学工学部 Acta Medica Okayama 0475-0071 13 1979 Aging and Reversion in Dilute Al-Ag Alloys 133 152 EN Mutsuo Ohta Teruto Kanadani Masuo Yamada Akira Sakakibara 10.18926/15715 Aging and reversion in dilute Al-Ag alloys are studied by means of the measurements of electrical resistivity. Results obtained are as follows: 1) Increase in the as-quenched resistivity is found for a low quenching temperature. This increase may be due to the fluctuation of solute concentration at the quenching temperature. 2) When the fluctuation exists in the alloy, the aging rate becomes slow and the maximum resistivity in the isothermal aging curve becomes small as the vacancyconcentration becomes low. The maximum resistivity becomes large again when the vacancy concentration becomes further lower, and finally the maximum does not appear. 3) These behaviors are explained in terms of the difference in the rate of growth of the G.P. zones in the regions of higher and lower solute concentration induced by the fluctuation and in terms of the change of this difference with vacancy concentration. 4) G.P. zones may be formed by the spinodal decomposition with indefinite surfaces at first, grown to larger ones with difinite surfaces and changed to ordered nzones in the alloy. 5) It is confirmed that G.P. zones are formed by the nucleation-and-growth mechanism also in Al-Ag alloys above the spinodal temperature. No potential conflict of interest relevant to this article was reported.

岡山大学工学部 Acta Medica Okayama 0475-0071 12 1978 A New Model for Structure of Poly (ethylene terephthalate) in its Glassy State 23 28 EN 10.18926/15714 A new realistic, structural model is proposed for the glassy solid state of poly(ethylene terephthalate) (PET). The model is considered basing on crystallization behaviors from the glassy state of PET, and in particular including the evidence from the estimation of chain folding energy in this report. When PET is quenched from its melt into the glassy state, irregular folds with lower conformational energy remain in glassy structure and disturb the three dimensional arrangement of the chains connected with the folds. In conclusion, we suggested that the structure of glassy PET is not in amorphous state which is represented by the interpenetrating random coil model, but in frozen metastable state which can be approached from the chain folded structure of polymer crystals. No potential conflict of interest relevant to this article was reported.

岡山大学工学部 Acta Medica Okayama 0475-0071 11 2 1977 An Investigation on Computational Methods of Traffic Assignment in Road Networks 51 71 EN 10.18926/15713 In this paper some computational methods of traffic assignment are proposed. At first solutions of traffic assignment by the equal travel times principle used nonlinear programmings are showed. They are a method to approximate by a quadratic programming, a method to use the SUMT transformation, a method to apply Rosen's gradient projection method and a method to apply the conjugate gradient projection method. Through a computational example the efficiency of them are compared. To decide route flows uniquely in traffic assignment by the equal travel times principle, a method requesting route flows such that the joint probability is a maximum under supposed a priori probabilities is proposed. In case of a traffic assignment in a large scale road network, it is significant to improve the efficiency of route searches. For this purpose a technique of minimum time route search by division of a network is proposed. No potential conflict of interest relevant to this article was reported.

岡山大学工学部 Acta Medica Okayama 0475-0071 13 1979 Effects of the Fluctuation of Solute Concentration in Al-Zn Alloys on the Aging at Low Temperatures; II. Electron Microscopy and Measurements of SAXS Intensity 119 132 EN Mutsuo Ohta Masuo Yamada Teruto Kanadani Akira Sakakibara 10.18926/15712 The effects of the fluctuation of solute concentration on the process of aging in Al-10wt % Zn alloy were studied by measurements of the intensity of small-angle X-ray scattering and by electron microscopy. Specimen was quenched from a higher temperature(T(Ql), mainly 300℃) to an intermediate temperature (T(Q2), 110~230℃), held there for a time, quenched again into iced water and aged isothermally at 0℃ or 40℃. Results obtained are as follows: (1) When the specimen was held at T(Q2) for a sufficient time and aged at relatively high temperatue(e.g. Ihr at 125℃ and aged at 40℃), a two-step increasing of both resistivity and integrated intensity was found. (2) Each of the steps has characteristics of the formation of G.P. zones by the spinodal decomposition. (3) When the maximum resistivity(p(max)) takes a minimum, Size distribution of the G.P. zones, estimated from the difference between Guinier and Porod radii, is much broader than that at p(max) in the usual direct quenching. (4) When the holding time at T(Q2) is long enough, the size distribution at p(max) is as broad as that at p(max) in the usual case. (5) After a prolonged aging under the condition that P(max) takes minimum, G.P. zones grow markedly and become oblate ellipsoidal with a major axis of about 20nm. (6) These results are consistently understood in terms of the fluctuation of solute concentration at T(Q2) and the change in the concentration of vacancies during annealing at T(Q2). That is, it is considered that these results are due to the difference in aging behavior between the regions of relatively high concentration and the ones of low concentration induced by the fluctuation. No potential conflict of interest relevant to this article was reported.

岡山大学工学部 Acta Medica Okayama 0475-0071 11 2 1977 Ozone and Chlorine in Wastewater Disinfection 37 49 EN 10.18926/15711 In this paper, we compare ozone with chlorine regarding following respects; (1)Disinfection efficiency (2)Oxidation power (3)Effects of secondary effluents treated by ozone or chlorine on aerobic microorganisms. Both ozone and chlorine are powerfull oxidizing agents. However,those are greatly different from each other in effects of treatment. Ozone is superior to chlorine in oxidation of organics, perfection of disinfection and effects on aerobic microorganisms. On the other hand, chlorine is superior in disinfection of Coliform group bacteria. Based on these results,it may be concluded that chlorination will be effective in disinfection of effluents which do not contain so much contaminants. However in case of rather highly cotaminated effluents, ozonation will be suitable. No potential conflict of interest relevant to this article was reported.

岡山大学工学部 Acta Medica Okayama 0475-0071 11 2 1977 Contraction Coefficients of Underflow Gates with a Vertical Lip 27 36 EN 10.18926/15710 In this paper the influence of a vertical lip upon the contraction coefficients of underflow gates is discussed. The coefficients of inclined gates with a vertical lip are investigated theoretically by using the method of conformal mapping. Solutions are obtained numerically for several values of the inclination of gate bottom. Theoretical solutions show that;as the length of a lip increases, the coefficient rapidly decreases from the value for the inclined gate, and when the length becomes of the order of a gate openning,it takes a value to be nearly equal to that for a vertical gate. These theoretical results are verified by experiments. No potential conflict of interest relevant to this article was reported.

岡山大学工学部 Acta Medica Okayama 0475-0071 13 1979 Effects of the Fluctuation of Solute Concentration in Al-Zn Alloys on the Aging at Low Temperatures; Ⅰ. Measurements of Electrical Resistivity 95 117 EN Mutsuo Ohta Teruto Kanadani Masuo Yamada Akira Sakakibara 10.18926/15709 Aging process in Al-Zn alloys was studied by the measurements of the electrical resistivity when the alloy was quenched from a high temperature, about 300℃ (the first quenching temperature), to an intermediate temperature, between 110℃ and 230℃ (the second quenching temperature), held at this temperature for a time, quenched again into iced water and aged at a low temperature. Variation of the holding time at the second quenching temperature brings about the variation of the isothermal aging curves. Maximum resistivity of the isothermal aging curve, p(max) , decreases at first, passes a minimum and then increases to reach a stationary value as the holding time at the intermediate temperature increases. It is pointed out that this phenomenon is mainly due to the fluctuation of solute concentration and the vacancy concentration decreasing at the intermediate temperature. No potential conflict of interest relevant to this article was reported.

岡山大学工学部 Acta Medica Okayama 0475-0071 13 1979 Computer Program of Line Balancing, Regarding Efficiency and Number of Stations as Variables 83 93 EN 10.18926/15706 To assign work elements to the work stations in an assembly or manufacturing line, various computer programs have been developed and used. And it does that the number of stations or the cycle time is even given. But in practice it is desirable to obtain the assignment which shows the highest efficiency of line balancing under all possible combinations of the number of stations and the cycle time. Therefore we propose a computer program of the assignment method in which the efficiency of line balancing, Ebb and the number of stations, NN are regarded as variables. In this method the minimum value (EEb) of efficiency and the constant term (d) by which Ebb is reduced are given previously. And for any COmbination of Ebb (EE<Ebb<lOO) and NN (l<NN<Nm : Nm calculated from EEb), the work elements are assigned to work stations, the precedence restrictions being used. Ebb is reduced by d from the ideal value (100) until the assignment to NN is obtained. The efficiency of the obtained assignment, Ebo is calculated. As Ebb<Ebo<Ebb+d, the calculation is continued until the assignment to NN, which shows the maximum efficiency, is obtained. In this process NN varies from Nm to 1 by 1 by 1. No potential conflict of interest relevant to this article was reported.

岡山大学工学部 Acta Medica Okayama 0475-0071 11 1 1976 An Analysis of Highway On-ramp Merging by Queuing Theory 31 43 EN 10.18926/15705 In this paper we deal with traffic behaviours on a section of highway including an on-ramp by means of queuing theory. It is the purpose of this paper to provide the adequate capacity for highway on-ramps, which is useful for the design of on-ramps and the traffic control of highway. The highway on-ramp merging is modeled as a queue and the system is solved. Then the maximum possible flows for merging from an on-ramp is obtained in a form of an function of through lane flows. The traffic capacity of an on-ramp is estimated from the relation between the average waiting time before merging and the incoming flow from an on-ramp, which is induced by the theory of queues. No potential conflict of interest relevant to this article was reported.

岡山大学工学部 Acta Medica Okayama 0475-0071 13 1979 Computer Program for Numerical Evaluation of the work 65 81 EN 10.18926/15704 We try to evaluate the manual work numerically from a point of view of the homogeneousness and the simultaneousness of both hands using the results of the micromotion study. The weighted coefficient and the balance index are used to evaluate the homogeneousness of both hands. And the simultaneous index is used to evaluate the simultaneous movement of both hands. It is necessary to make a program in order to use efficiently the method to calculate the indexes or the coefficients. Therefore the computer program of these methods is mentioned in this paper. No potential conflict of interest relevant to this article was reported.

岡山大学工学部 Acta Medica Okayama 0475-0071 11 1 1976 Optimal Control of a Nuclear Power Reactor Core with a Coupled Nuclear Thermo-hydrodynamics Model 19 30 EN Ryuji Koga 10.18926/15703 An optimal control is giyen for regulating power distribution in a nuclear power reactor which has cylindrical geometry. The space dependence of the system is described by expanding space depenident variables by Helmholtz modes. Results are obtained through the principle of optimality and are described by the Riccati-type algebraic equation that the optimal feedback coefficients should satisfy. Use of an integral equation as the system equation makes it possible to deal with actual controlling apparatuses: control rods or rod clusters. No potential conflict of interest relevant to this article was reported.

岡山大学工学部 Acta Medica Okayama 0475-0071 13 1979 AC Chopper Circuit with Lagging Reactive Load 53 64 EN 10.18926/15702 An ac chopper circuit, which chops an ac voltage in a complete cycle for any lagging reactive load, is devised. The circuit is constructed of two ac-switches composed of power transistors and diodes. The load voltage is smoothly controlled by varying the time ratio of ac-switch. Transistors operate in a highfrequency chopping mode, thereby the ripples of the source current and the load current are easily filtered. Furthermore the input power factor of this model is better than that of the thyristor phase control circuit. In this paper, the construction and the driving method of this model are described. No potential conflict of interest relevant to this article was reported.

岡山大学工学部 Acta Medica Okayama 0475-0071 11 1 1976 Anomalous Electric Fields in n-InSb under High Magnetic Fields. I-Experiment 7 18 EN 10.18926/15701 An investigation was made of the anomalous electric field in its various aspects in n-type InSb subjected to strong magnetic field at 77K and 273K, which lead to the conclusion that no open contradiction arose between a part of the present observations and the predictions attainable from Yoshida's model of semimetals. There remained, however, the other part of the experimental results unexplained, being rather natural since an inner property of indium antimonide does not seem so simple comparing with the compensated metals, bismuth and antimony. Especially as for the mechanism of an inversion phenomenon of the polarity of a negative anomalous field at a critical pulse current, we have no available theory to explain at present stage. No potential conflict of interest relevant to this article was reported.