start-ver=1.4 cd-journal=joma no-vol=28 cd-vols= no-issue=1 article-no= start-page=39 end-page=50 dt-received= dt-revised= dt-accepted= dt-pub-year=1993 dt-pub=19931130 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=A Simple Model for Hydrogen-Bonding Ferroelectrics en-subtitle= kn-subtitle= en-abstract= kn-abstract=There are some substances in which their hydrogen bonds are considered to play quite important roles in their ferroelectric or antiferroelectric phase transition. These ferroelectrics usually have large isotope effects in phase transition temperatures and we expect the physics of hydrogen bonds is closely related to the effects. We propose a simple model describing the isolated hydrogen bond. Based on quantum-mechanical analyses of this model, we study the difference between the behavior of a proton and a deuteron in hydrogen bonds. en-copyright= kn-copyright= en-aut-name=TotsujiChieko en-aut-sei=Totsuji en-aut-mei=Chieko kn-aut-name=“Œ’ÒçŽ}Žq kn-aut-sei=“Œ’Ò kn-aut-mei=çŽ}Žq aut-affil-num=1 ORCID= en-aut-name= en-aut-sei= en-aut-mei= kn-aut-name=MatsubaraTakeo kn-aut-sei=Matsubara kn-aut-mei=Takeo aut-affil-num=2 ORCID= affil-num=1 en-affil= kn-affil=Department of Electrical and Electronic Engineering affil-num=2 en-affil= kn-affil=Institute for Condensed Matter Theory END start-ver=1.4 cd-journal=joma no-vol=28 cd-vols= no-issue=2 article-no= start-page=53 end-page=58 dt-received= dt-revised= dt-accepted= dt-pub-year=1994 dt-pub=19940315 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Note on the Piezoelectric Constant of PbZrO(3)-PbTiO(3)(PZT) en-subtitle= kn-subtitle= en-abstract= kn-abstract=One of the best known solid solution of perovskites is the PbTiO(3)-PbZrO(3) system which is usually abbreviated as PZT. In the phase diagram of this system, there is a drastic phase change from tetragonal to rhombohedral at the molar ratio around 50:50. The PZT crystals are widely used as a practical piezoelectric material because of its very strong piezoelectric effect near this morphotropic phase boundary. We try to explain this anomaly in piezoelectric constant by a phenomenological theory. en-copyright= kn-copyright= en-aut-name=TotsujiChieko en-aut-sei=Totsuji en-aut-mei=Chieko kn-aut-name=“Œ’ÒçŽ}Žq kn-aut-sei=“Œ’Ò kn-aut-mei=çŽ}Žq aut-affil-num=1 ORCID= en-aut-name= en-aut-sei= en-aut-mei= kn-aut-name=MatsubaraTakeo kn-aut-sei=Matsubara kn-aut-mei=Takeo aut-affil-num=2 ORCID= en-aut-name= en-aut-sei= en-aut-mei= kn-aut-name=MiyataSatoru kn-aut-sei=Miyata kn-aut-mei=Satoru aut-affil-num=3 ORCID= affil-num=1 en-affil= kn-affil=Department of Electrical and Electronic Engineering affil-num=2 en-affil= kn-affil=Okayama University of Science affil-num=3 en-affil= kn-affil=Okayama University of Science END start-ver=1.4 cd-journal=joma no-vol=29 cd-vols= no-issue=1 article-no= start-page=7 end-page=14 dt-received= dt-revised= dt-accepted= dt-pub-year=1994 dt-pub=19941130 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Electronic States in Semiconductor Quantum Dot with Fluctuating Interfaces en-subtitle= kn-subtitle= en-abstract= kn-abstract=Effects of interface fluctuations on the electronic states in semiconductor quantum dots are analyzed on the basis of numerical solutions for ground state wave functions and energy eigenvalues. It is shown that the effective volume of confinement becomes smaller than the real volume of quantum dots due to fluctuation. This effect comes from the fact that the wave functions with larger characteristic wavelength are not able to deform themselves following the fluctuation of interfaces exactly. en-copyright= kn-copyright= en-aut-name= en-aut-sei= en-aut-mei= kn-aut-name=HiroyukiTachibana kn-aut-sei=Hiroyuki kn-aut-mei=Tachibana aut-affil-num=1 ORCID= en-aut-name=TotsujiHiroo en-aut-sei=Totsuji en-aut-mei=Hiroo kn-aut-name=“Œ’Ò_•v kn-aut-sei=“Œ’Ò kn-aut-mei=_•v aut-affil-num=2 ORCID= en-aut-name=NaraShigetoshi en-aut-sei=Nara en-aut-mei=Shigetoshi kn-aut-name=“Þ—Çdr kn-aut-sei=“Þ—Ç kn-aut-mei=dr aut-affil-num=3 ORCID= en-aut-name=TotsujiChieko en-aut-sei=Totsuji en-aut-mei=Chieko kn-aut-name=“Œ’ÒçŽ}Žq kn-aut-sei=“Œ’Ò kn-aut-mei=çŽ}Žq aut-affil-num=4 ORCID= affil-num=1 en-affil= kn-affil=Department of Electrical and Electronic Engineering affil-num=2 en-affil= kn-affil=Department of Electrical and Electronic Engineering affil-num=3 en-affil= kn-affil=Department of Electrical and Electronic Engineering affil-num=4 en-affil= kn-affil=Department of Electrical and Electronic Engineering END start-ver=1.4 cd-journal=joma no-vol=29 cd-vols= no-issue=1 article-no= start-page=15 end-page=22 dt-received= dt-revised= dt-accepted= dt-pub-year=1994 dt-pub=19941130 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Note on the Electronic Structure of C(60) Molecule en-subtitle= kn-subtitle= en-abstract= kn-abstract=A molecular orbital approach to the electronic structure of C(60) molecule is formulated on the basis of optimized bond orbital model and the stability of the truncated icosahedron structure is examined. en-copyright= kn-copyright= en-aut-name=TotsujiChieko en-aut-sei=Totsuji en-aut-mei=Chieko kn-aut-name=“Œ’ÒçŽ}Žq kn-aut-sei=“Œ’Ò kn-aut-mei=çŽ}Žq aut-affil-num=1 ORCID= en-aut-name=MatsubaraTakeo en-aut-sei=Matsubara en-aut-mei=Takeo kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=ObuchiMasumi en-aut-sei=Obuchi en-aut-mei=Masumi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= affil-num=1 en-affil= kn-affil=Department of Electrical and Electronic Engineering affil-num=2 en-affil= kn-affil=Okayama University of Science affil-num=3 en-affil= kn-affil=Okayama University of Science END start-ver=1.4 cd-journal=joma no-vol=29 cd-vols= no-issue=2 article-no= start-page=67 end-page=76 dt-received= dt-revised= dt-accepted= dt-pub-year=1995 dt-pub=19950327 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=The Electronic Structure of C(60) Molecule -Structure of ƒÎ-electron Band- en-subtitle= kn-subtitle= en-abstract= kn-abstract=The ƒÎ-electron band of C(60) molecule has been obtained by the tight binding approximation. Application of molecular orbital wave functions derived on the basis of the optimized bond orbital model gives, with simpler calculations, the results in satisfactory agreement with those of previous theoretical analyses. en-copyright= kn-copyright= en-aut-name=TotsujiChieko en-aut-sei=Totsuji en-aut-mei=Chieko kn-aut-name=“Œ’ÒçŽ}Žq kn-aut-sei=“Œ’Ò kn-aut-mei=çŽ}Žq aut-affil-num=1 ORCID= en-aut-name= en-aut-sei= en-aut-mei= kn-aut-name=MatsubaraTakeo kn-aut-sei=Matsubara kn-aut-mei=Takeo aut-affil-num=2 ORCID= en-aut-name= en-aut-sei= en-aut-mei= kn-aut-name=ObuchiMasumi kn-aut-sei=Obuchi kn-aut-mei=Masumi aut-affil-num=3 ORCID= affil-num=1 en-affil= kn-affil=Department of Electrical and Electronic Engineering affil-num=2 en-affil= kn-affil=Okayama University of Science affil-num=3 en-affil= kn-affil=Okayama University of Science END start-ver=1.4 cd-journal=joma no-vol=30 cd-vols= no-issue=1 article-no= start-page=75 end-page=87 dt-received= dt-revised= dt-accepted= dt-pub-year=1995 dt-pub=19951228 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Molecular Dynamics of Yukawa System (Dust Plasma) with Deformable Periodic Boundary Conditions: Formulation en-subtitle= kn-subtitle= en-abstract= kn-abstract=Molecular dynamics of the Yukawa system, the system of particles interacting via the Yukawa or the screened Coulomb potential, are formulated for various statistical ensembles and external conditions. The Yukawa potential smoothly interpolates the long-range Coulomb and the short-range interactions by adjusting a single parameter, the screening length. In order to reduce the effect of boundaries, the periodic boundary conditions are imposed and the deformations of the fundamental vectors of periodicity are taken into account. Ewald-type expressions for interaction energy, force, and kinematic pressure are given explicitly. en-copyright= kn-copyright= en-aut-name=TotsujiHiroo en-aut-sei=Totsuji en-aut-mei=Hiroo kn-aut-name=“Œ’Ò_•v kn-aut-sei=“Œ’Ò kn-aut-mei=_•v aut-affil-num=1 ORCID= en-aut-name=InoueYoshihiko en-aut-sei=Inoue en-aut-mei=Yoshihiko kn-aut-name=ˆäã‰Ã•F kn-aut-sei=ˆäã kn-aut-mei=‰Ã•F aut-affil-num=2 ORCID= en-aut-name=KishimotoTokunari en-aut-sei=Kishimoto en-aut-mei=Tokunari kn-aut-name=ŠÝ–{“Ä–ç kn-aut-sei=ŠÝ–{ kn-aut-mei=“Ä–ç aut-affil-num=3 ORCID= en-aut-name=TotsujiChieko en-aut-sei=Totsuji en-aut-mei=Chieko kn-aut-name=“Œ’ÒçŽ}Žq kn-aut-sei=“Œ’Ò kn-aut-mei=çŽ}Žq aut-affil-num=4 ORCID= en-aut-name=NaraShigetoshi en-aut-sei=Nara en-aut-mei=Shigetoshi kn-aut-name=“Þ—Çdr kn-aut-sei=“Þ—Ç kn-aut-mei=dr aut-affil-num=5 ORCID= affil-num=1 en-affil= kn-affil=Department of Electrical and Electronic Engineering affil-num=2 en-affil= kn-affil=Department of Electrical and Electronic Engineering affil-num=3 en-affil= kn-affil=Department of Electrical and Electronic Engineering affil-num=4 en-affil= kn-affil=Department of Electrical and Electronic Engineering affil-num=5 en-affil= kn-affil=Faculty ofIntegrated Arts and Sciences, Hiroshima University END start-ver=1.4 cd-journal=joma no-vol=30 cd-vols= no-issue=1 article-no= start-page=89 end-page=97 dt-received= dt-revised= dt-accepted= dt-pub-year=1995 dt-pub=19951228 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Electronic Structure of Mixed Perovskite Oxides en-subtitle= kn-subtitle= en-abstract= kn-abstract=Based on the tight-binding method, electronic bands of the mixed perovskite oxides are calculated in order to develop the electronic theory of ferroelectric phase transitions in these mixtures which are difficult to describe within the phenomenological theories. Diagonal elements of Hamiltonian matrix of parent materials are assumed to differ by 0.1eV and mixtures are simulated by lattices of supercells containing 2(3) = 8 or 3(3) = 27 unit cells randomly assigned to either material. The width of the conduction and valence bands have maxima and the band gap has a minimum at intermediate mixing ratio. Results are in agreement with those of other analyses on random systems and even 2(3)-cell computation seems to serve as a first approximation for our purpose. en-copyright= kn-copyright= en-aut-name=TotsujiChieko en-aut-sei=Totsuji en-aut-mei=Chieko kn-aut-name=“Œ’ÒçŽ}Žq kn-aut-sei=“Œ’Ò kn-aut-mei=çŽ}Žq aut-affil-num=1 ORCID= en-aut-name= en-aut-sei= en-aut-mei= kn-aut-name=SanakaYoshiaki kn-aut-sei=Sanaka kn-aut-mei=Yoshiaki aut-affil-num=2 ORCID= en-aut-name=TotsujiHiroo en-aut-sei=Totsuji en-aut-mei=Hiroo kn-aut-name=“Œ’Ò_•v kn-aut-sei=“Œ’Ò kn-aut-mei=_•v aut-affil-num=3 ORCID= affil-num=1 en-affil= kn-affil=Department of Electrical and Electronic Engineering affil-num=2 en-affil= kn-affil=Department of Electrical and Electronic Engineering affil-num=3 en-affil= kn-affil=Department of Electrical and Electronic Engineering END start-ver=1.4 cd-journal=joma no-vol=30 cd-vols= no-issue=2 article-no= start-page=39 end-page=43 dt-received= dt-revised= dt-accepted= dt-pub-year=1996 dt-pub=19960329 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=A Simple Model for Oxygen Conduction in Some Perovskite Compounds en-subtitle= kn-subtitle= en-abstract= kn-abstract=A simple model for oxygen ion conduction in perovskite compounds is proposed. The potential for an oxygen ion is calculated as the sum of the long range Coulomb potential and short range repulsive potential in a cubic lattice. The activation energy is estimated as the difference in the values of potential at the barrier and at the stable site. When appropriate conditions are satisfied, the activation energy has a minimum as a function of lattice constant in accordance with recent experiments. en-copyright= kn-copyright= en-aut-name=TotsujiChieko en-aut-sei=Totsuji en-aut-mei=Chieko kn-aut-name=“Œ’ÒçŽ}Žq kn-aut-sei=“Œ’Ò kn-aut-mei=çŽ}Žq aut-affil-num=1 ORCID= affil-num=1 en-affil= kn-affil=Department of Electrical and Electronic Engineering END start-ver=1.4 cd-journal=joma no-vol=30 cd-vols= no-issue=2 article-no= start-page=27 end-page=37 dt-received= dt-revised= dt-accepted= dt-pub-year=1996 dt-pub=19960329 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Yukawa System in One-Dimensional External Field en-subtitle= kn-subtitle= en-abstract= kn-abstract=The behavior of the Yukawa system in external one-dimensional force fields is analyzed by the molecular dynamics simulation. The formation of layered structures at low temperatures is observed and the relation between the number of layers and characteristic parameters of the system is obtained. Since the Yukawa system serves as a model of clouds of dust particles in plasmas (dusty plasma) which play an important role in plasma processes of semiconductor engineering, the results may be useful to control the quality of semiconductor wafers in such processes. In simulations, periodic boundary conditions are imposed in two dimensions and deformations of periodic boundaries are allowed in order to reduce the effect of boundaries without giving too much constraint on the symmetry. en-copyright= kn-copyright= en-aut-name=TotsujiHiroo en-aut-sei=Totsuji en-aut-mei=Hiroo kn-aut-name=“Œ’Ò_•v kn-aut-sei=“Œ’Ò kn-aut-mei=_•v aut-affil-num=1 ORCID= en-aut-name=KishimotoTokunari en-aut-sei=Kishimoto en-aut-mei=Tokunari kn-aut-name=ŠÝ–{“Ä–ç kn-aut-sei=ŠÝ–{ kn-aut-mei=“Ä–ç aut-affil-num=2 ORCID= en-aut-name=TotsujiChieko en-aut-sei=Totsuji en-aut-mei=Chieko kn-aut-name=“Œ’ÒçŽ}Žq kn-aut-sei=“Œ’Ò kn-aut-mei=çŽ}Žq aut-affil-num=3 ORCID= affil-num=1 en-affil= kn-affil=Department of Electrical and Electronic Engineering affil-num=2 en-affil= kn-affil=Department of Electrical and Electronic Engineering affil-num=3 en-affil= kn-affil=Department of Electrical and Electronic Engineering END start-ver=1.4 cd-journal=joma no-vol=31 cd-vols= no-issue=1 article-no= start-page=19 end-page=33 dt-received= dt-revised= dt-accepted= dt-pub-year=1996 dt-pub=19961227 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Structure of Dusty Plasma as Yukawa System Confined in One-Dimensional External Fields en-subtitle= kn-subtitle= en-abstract= kn-abstract=As a model of dusty plasmas in external fields, Yuka.wa system in a one-dimensional external field is analyzed by molecular dynamics simulations and theoretical approaches. It is shown that particles form clear thin layers (sheets) at low temperatures and the number of layers changes discretely with characteristic parameters of the system, accompanying the rearrangements of whole system from nearly equipartitioned layers to also nearly equipartitioned layers. The number, positions and populations of layers are obtained as functions of characteristic parameters. The shell (sheet) model which has been successful for confined one-component plasmas is extended to this system and results of numerical experiments are reproduced to a good accuracy. The effect of cohesive energy in each layer is of essential importance to reproduce discrete changes in the number of sheets. en-copyright= kn-copyright= en-aut-name=TotsujiHiroo en-aut-sei=Totsuji en-aut-mei=Hiroo kn-aut-name=“Œ’Ò_•v kn-aut-sei=“Œ’Ò kn-aut-mei=_•v aut-affil-num=1 ORCID= en-aut-name=KishimotoTokunari en-aut-sei=Kishimoto en-aut-mei=Tokunari kn-aut-name=ŠÝ–{“Ä–ç kn-aut-sei=ŠÝ–{ kn-aut-mei=“Ä–ç aut-affil-num=2 ORCID= en-aut-name=TotsujiChieko en-aut-sei=Totsuji en-aut-mei=Chieko kn-aut-name=“Œ’ÒçŽ}Žq kn-aut-sei=“Œ’Ò kn-aut-mei=çŽ}Žq aut-affil-num=3 ORCID= affil-num=1 en-affil= kn-affil=Department of Electrical and Electronic Engineering affil-num=2 en-affil= kn-affil=Department of Electrical and Electronic Engineering affil-num=3 en-affil= kn-affil=Department of Electrical and Electronic Engineering END start-ver=1.4 cd-journal=joma no-vol=32 cd-vols= no-issue=1-2 article-no= start-page=43 end-page=54 dt-received= dt-revised= dt-accepted= dt-pub-year=1998 dt-pub=19980420 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Numerical Analysis of a Model for Isolated Hydrogen Bond en-subtitle= kn-subtitle= en-abstract= kn-abstract=Large isotope effects have been observed in various kinds of hydrogen bonded ferro / antiferroelectrics. In clariflying their origin, themodynamic properties of the hydrogen bond are of essential importance. Two numerical methods are applied to analyze the model for isolated hydrogen bond at finite temperatures and the results of excited energy levels of proton or deuteron are examined. It is found that the second excited state is not far enough from the first excited state to be neglected discussing themodynamic properties of hydrogen especially in their ordered states. en-copyright= kn-copyright= en-aut-name=TotsujiChieko en-aut-sei=Totsuji en-aut-mei=Chieko kn-aut-name=“Œ’ÒçŽ}Žq kn-aut-sei=“Œ’Ò kn-aut-mei=çŽ}Žq aut-affil-num=1 ORCID= en-aut-name= en-aut-sei= en-aut-mei= kn-aut-name=MatsubaraTakeo kn-aut-sei=Matsubara kn-aut-mei=Takeo aut-affil-num=2 ORCID= affil-num=1 en-affil= kn-affil=Department of Electrical and Electronic Engineering affil-num=2 en-affil= kn-affil=Institute for Condensed Matter Theory END start-ver=1.4 cd-journal=joma no-vol=32 cd-vols= no-issue=1-2 article-no= start-page=23 end-page=41 dt-received= dt-revised= dt-accepted= dt-pub-year=1998 dt-pub=19980420 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Structure of Yukawa (Dusty Plasma) Mixtures en-subtitle= kn-subtitle= en-abstract= kn-abstract=Parameters characterizing the structure ot confined Yukawa system are estimated for 'dusty plasmas', clouds of charged macroscopic particles formed near the boundary between plasma and the sheath and leviated by negatively biased electrode. When we have dust particles with different ratios of charge to mass, they form a two-dimensional Yukawa mixture or separate two-dimensional one-companent Yukawa systems, depending on the charge density in the sheath and number density of dust particles. In order to provide a basis for numerical simulations on Yukawa mixtures including Coulombic case, we summarize mathematical expressions necessary for molecular dynamics. en-copyright= kn-copyright= en-aut-name=TotsujiHiroo en-aut-sei=Totsuji en-aut-mei=Hiroo kn-aut-name=“Œ’Ò_•v kn-aut-sei=“Œ’Ò kn-aut-mei=_•v aut-affil-num=1 ORCID= en-aut-name=KishimotoTokunari en-aut-sei=Kishimoto en-aut-mei=Tokunari kn-aut-name=ŠÝ–{“Ä–ç kn-aut-sei=ŠÝ–{ kn-aut-mei=“Ä–ç aut-affil-num=2 ORCID= en-aut-name=TotsujiChieko en-aut-sei=Totsuji en-aut-mei=Chieko kn-aut-name=“Œ’ÒçŽ}Žq kn-aut-sei=“Œ’Ò kn-aut-mei=çŽ}Žq aut-affil-num=3 ORCID= affil-num=1 en-affil= kn-affil=Department of Electrical and Electronic Engineering affil-num=2 en-affil= kn-affil=Department of Electrical and Electronic Engineering affil-num=3 en-affil= kn-affil=Department of Electrical and Electronic Engineering END start-ver=1.4 cd-journal=joma no-vol=33 cd-vols= no-issue=2 article-no= start-page=71 end-page=77 dt-received= dt-revised= dt-accepted= dt-pub-year=1999 dt-pub=19990427 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=O(N) Tight-Binding Algorithm for Large-Scale Molecular Dynamics Simulations en-subtitle= kn-subtitle= en-abstract= kn-abstract=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. en-copyright= kn-copyright= en-aut-name=TsurutaKenji en-aut-sei=Tsuruta en-aut-mei=Kenji kn-aut-name=’ß“cŒ’“ñ kn-aut-sei=’ß“c kn-aut-mei=Œ’“ñ aut-affil-num=1 ORCID= en-aut-name=TotsujiHiroo en-aut-sei=Totsuji en-aut-mei=Hiroo kn-aut-name=“Œ’Ò_•v kn-aut-sei=“Œ’Ò kn-aut-mei=_•v aut-affil-num=2 ORCID= en-aut-name=TotsujiChieko en-aut-sei=Totsuji en-aut-mei=Chieko kn-aut-name=“Œ’ÒçŽ}Žq kn-aut-sei=“Œ’Ò kn-aut-mei=çŽ}Žq aut-affil-num=3 ORCID= affil-num=1 en-affil= kn-affil=Department of Electrical and Electronic Engineering affil-num=2 en-affil= kn-affil=Department of Electrical and Electronic Engineering affil-num=3 en-affil= kn-affil=Department of Electrical and Electronic Engineering END start-ver=1.4 cd-journal=joma no-vol=33 cd-vols= no-issue=2 article-no= start-page=61 end-page=69 dt-received= dt-revised= dt-accepted= dt-pub-year=1999 dt-pub=19990427 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Multicomponent Plasmas in Penning-Malmberg Traps en-subtitle= kn-subtitle= en-abstract= kn-abstract=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. en-copyright= kn-copyright= en-aut-name=TotsujiHiroo en-aut-sei=Totsuji en-aut-mei=Hiroo kn-aut-name=“Œ’Ò_•v kn-aut-sei=“Œ’Ò kn-aut-mei=_•v aut-affil-num=1 ORCID= en-aut-name=TsurutaKenji en-aut-sei=Tsuruta en-aut-mei=Kenji kn-aut-name=’ß“cŒ’“ñ kn-aut-sei=’ß“c kn-aut-mei=Œ’“ñ aut-affil-num=2 ORCID= en-aut-name=TotsujiChieko en-aut-sei=Totsuji en-aut-mei=Chieko kn-aut-name=“Œ’ÒçŽ}Žq kn-aut-sei=“Œ’Ò kn-aut-mei=çŽ}Žq aut-affil-num=3 ORCID= affil-num=1 en-affil= kn-affil=Department of Electrical and Electronic Engineering affil-num=2 en-affil= kn-affil=Department of Electrical and Electronic Engineering affil-num=3 en-affil= kn-affil=Department of Electrical and Electronic Engineering END start-ver=1.4 cd-journal=joma no-vol=33 cd-vols= no-issue=2 article-no= start-page=51 end-page=59 dt-received= dt-revised= dt-accepted= dt-pub-year=1999 dt-pub=19990427 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Density Functional Molecular Dynamics of Hydrogen Plasma en-subtitle= kn-subtitle= en-abstract= kn-abstract=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 ƒÁ(s), we have increasingly strong screening of proton charge by electrons and the decrease of electron density in the domain between protons. en-copyright= kn-copyright= en-aut-name=TotsujiHiroo en-aut-sei=Totsuji en-aut-mei=Hiroo kn-aut-name=“Œ’Ò_•v kn-aut-sei=“Œ’Ò kn-aut-mei=_•v aut-affil-num=1 ORCID= en-aut-name=TsurutaKenji en-aut-sei=Tsuruta en-aut-mei=Kenji kn-aut-name=’ß“cŒ’“ñ kn-aut-sei=’ß“c kn-aut-mei=Œ’“ñ aut-affil-num=2 ORCID= en-aut-name=TotsujiChieko en-aut-sei=Totsuji en-aut-mei=Chieko kn-aut-name=“Œ’ÒçŽ}Žq kn-aut-sei=“Œ’Ò kn-aut-mei=çŽ}Žq aut-affil-num=3 ORCID= affil-num=1 en-affil= kn-affil=Department of Electrical and Electronic Engineering affil-num=2 en-affil= kn-affil=Department of Electrical and Electronic Engineering affil-num=3 en-affil= kn-affil=Department of Electrical and Electronic Engineering END start-ver=1.4 cd-journal=joma no-vol=35 cd-vols= no-issue=1-2 article-no= start-page=63 end-page=75 dt-received= dt-revised= dt-accepted= dt-pub-year=2001 dt-pub=20010327 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Nonorthogonal Tight-Binding Molecular Dynamics for Si(1-x)Ge(x) Alloys en-subtitle= kn-subtitle= en-abstract= kn-abstract=We present a theoretical study of Si(1-x)Ge(x) alloys based on tight-binding molecular dynamics (TBMD) calculations. First, we introduce a new set of nonorthogonal tight-binding parameters for silicon and germanium based on the previous work by Menon and Subbaswamy [Phys. Rev. B 55, 9231 (1997); J. Phys: Condens. Matter 10, 10991 (1998)]. We then apply the method to structural analyses of Si(1-x)Ge(x) alloys. The equilibrium volume and atomic structure for a given x are obtained by the TBMD method. We also calculate the bulk modulus B, elastic constants C(11), C(12) and C(44) as a function of x. The results show that the moduli vary monotonically, but nonlinearly, between the values of Si crystal and Ge crystal. The validity of the results is also discussed. en-copyright= kn-copyright= en-aut-name= en-aut-sei= en-aut-mei= kn-aut-name=ShinomiyaShigeru kn-aut-sei=Shinomiya kn-aut-mei=Shigeru aut-affil-num=1 ORCID= en-aut-name=TotsujiChieko en-aut-sei=Totsuji en-aut-mei=Chieko kn-aut-name=“Œ’ÒçŽ}Žq kn-aut-sei=“Œ’Ò kn-aut-mei=çŽ}Žq aut-affil-num=2 ORCID= en-aut-name=TsurutaKenji en-aut-sei=Tsuruta en-aut-mei=Kenji kn-aut-name=’ß“cŒ’“ñ kn-aut-sei=’ß“c kn-aut-mei=Œ’“ñ aut-affil-num=3 ORCID= en-aut-name=TotsujiHiroo en-aut-sei=Totsuji en-aut-mei=Hiroo kn-aut-name=“Œ’Ò_•v kn-aut-sei=“Œ’Ò kn-aut-mei=_•v aut-affil-num=4 ORCID= affil-num=1 en-affil= kn-affil=Graduate School of Natural Science and Technology affil-num=2 en-affil= kn-affil=Department of Electrical and Electronic Engineering affil-num=3 en-affil= kn-affil=Department of Electrical and Electronic Engineering affil-num=4 en-affil= kn-affil=Department of Electrical and Electronic Engineering END start-ver=1.4 cd-journal=joma no-vol=35 cd-vols= no-issue=1-2 article-no= start-page=77 end-page=95 dt-received= dt-revised= dt-accepted= dt-pub-year=2001 dt-pub=20010327 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Molecular Dynamics of Yukawa System using the Fast Multipole Method en-subtitle= kn-subtitle= en-abstract= kn-abstract=In order to perform the large-scale molecular dynamics simulation of the Yukawa system, a mathematical expression for molecular dynamics using the fast multipole method is described. The model simulations are also performed to test the performance of our implementation of the FMM. en-copyright= kn-copyright= en-aut-name= en-aut-sei= en-aut-mei= kn-aut-name=KishimotoTokunari kn-aut-sei=Kishimoto kn-aut-mei=Tokunari aut-affil-num=1 ORCID= en-aut-name=TotsujiChieko en-aut-sei=Totsuji en-aut-mei=Chieko kn-aut-name=“Œ’ÒçŽ}Žq kn-aut-sei=“Œ’Ò kn-aut-mei=çŽ}Žq aut-affil-num=2 ORCID= en-aut-name=TsurutaKenji en-aut-sei=Tsuruta en-aut-mei=Kenji kn-aut-name=’ß“cŒ’“ñ kn-aut-sei=’ß“c kn-aut-mei=Œ’“ñ aut-affil-num=3 ORCID= en-aut-name=TotsujiHiroo en-aut-sei=Totsuji en-aut-mei=Hiroo kn-aut-name=“Œ’Ò_•v kn-aut-sei=“Œ’Ò kn-aut-mei=_•v aut-affil-num=4 ORCID= affil-num=1 en-affil= kn-affil=Graduate School of Natural Science and Technology affil-num=2 en-affil= kn-affil=Department of Electrical and Electronic Engineering affil-num=3 en-affil= kn-affil=Department of Electrical and Electronic Engineering affil-num=4 en-affil= kn-affil=Department of Electrical and Electronic Engineering END start-ver=1.4 cd-journal=joma no-vol=39 cd-vols= no-issue=1 article-no= start-page=46 end-page=51 dt-received= dt-revised= dt-accepted= dt-pub-year=2005 dt-pub=200501 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Electron Dynamics in Semiconducting Nanowires: A Real-Space, Polynomial-Expansion Approach en-subtitle= kn-subtitle= en-abstract= kn-abstract=We present a real-space, polynomial-expansion approach to electron dynamics in nanostructured semiconductors. The Chebyshev expansion method is employed for efficient calculation of timeevolution of single-electron wave function. Details of the formulation are described. The method is applied to the electron transport in nanostructured semiconductors such as Si nanowires. The mean-square displacement and diffusivity of electron in Si chains are obtained as functions of length of the chains. The results show clearly ballistic behavior of electron in the pure Si chain. en-copyright= kn-copyright= en-aut-name=KadonoKeisuke en-aut-sei=Kadono en-aut-mei=Keisuke kn-aut-name=–å–ìŒb“T kn-aut-sei=–å–ì kn-aut-mei=Œb“T aut-affil-num=1 ORCID= en-aut-name=TotsujiChieko en-aut-sei=Totsuji en-aut-mei=Chieko kn-aut-name=“Œ’ÒçŽ}Žq kn-aut-sei=“Œ’Ò kn-aut-mei=çŽ}Žq aut-affil-num=2 ORCID= en-aut-name=TsurutaKenji en-aut-sei=Tsuruta en-aut-mei=Kenji kn-aut-name=’ß“cŒ’“ñ kn-aut-sei=’ß“c kn-aut-mei=Œ’“ñ aut-affil-num=3 ORCID= en-aut-name=TotsujiHiroo en-aut-sei=Totsuji en-aut-mei=Hiroo kn-aut-name=“Œ’Ò_•v kn-aut-sei=“Œ’Ò kn-aut-mei=_•v aut-affil-num=4 ORCID= affil-num=1 en-affil= kn-affil=Graduate School of Natural Science and Technology, Okayama University affil-num=2 en-affil= kn-affil=Department of Electrical and Electronic Engineering, Faculty of Engineering, Okayama University affil-num=3 en-affil= kn-affil=Department of Electrical and Electronic Engineering, Faculty of Engineering, Okayama University affil-num=4 en-affil= kn-affil=Department of Electrical and Electronic Engineering, Faculty of Engineering, Okayama University END start-ver=1.4 cd-journal=joma no-vol=39 cd-vols= no-issue=1 article-no= start-page=52 end-page=55 dt-received= dt-revised= dt-accepted= dt-pub-year=2005 dt-pub=200501 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Large-Scale Molecular Dynamics Simulation of Coulomb Clusters: A Finite-Temperature Analysis en-subtitle= kn-subtitle= en-abstract= kn-abstract=Thermal behavior of Coulomb clusters in a three dimensional confining potential is investigated by molecular dynamics simulations for system sizes of 1,000 to 20,288 ions. The specific heat of the system of shell-structured 20,000 ions is peaked almost at the same temperature as the system of bcc-structured 20,288 ions with much sharper structure for the latter. The diffusion coefficient and the peak to valley ratio of the two-dimensional pair distribution function on the outermost shell are obtained both as a function of temperature. The rotational movement of each shell in the system of 104 ions is observed. en-copyright= kn-copyright= en-aut-name=KanamoriKatsuya en-aut-sei=Kanamori en-aut-mei=Katsuya kn-aut-name=‹àXŽ–ç kn-aut-sei=‹àX kn-aut-mei=Ž–ç aut-affil-num=1 ORCID= en-aut-name=TotsujiChieko en-aut-sei=Totsuji en-aut-mei=Chieko kn-aut-name=“Œ’ÒçŽ}Žq kn-aut-sei=“Œ’Ò kn-aut-mei=çŽ}Žq aut-affil-num=2 ORCID= en-aut-name=TsurutaKenji en-aut-sei=Tsuruta en-aut-mei=Kenji kn-aut-name=’ß“cŒ’“ñ kn-aut-sei=’ß“c kn-aut-mei=Œ’“ñ aut-affil-num=3 ORCID= en-aut-name=TotsujiHiroo en-aut-sei=Totsuji en-aut-mei=Hiroo kn-aut-name=“Œ’Ò_•v kn-aut-sei=“Œ’Ò kn-aut-mei=_•v aut-affil-num=4 ORCID= affil-num=1 en-affil= kn-affil=Graduate School of Natural Science and Technology, Okayama University affil-num=2 en-affil= kn-affil=Department of Electrical and Electronic Engineering, Faculty of Engineering, Okayama University affil-num=3 en-affil= kn-affil=Department of Electrical and Electronic Engineering, Faculty of Engineering, Okayama University affil-num=4 en-affil= kn-affil=Department of Electrical and Electronic Engineering, Faculty of Engineering, Okayama University END start-ver=1.4 cd-journal=joma no-vol=40 cd-vols= no-issue=1 article-no= start-page=40 end-page=43 dt-received= dt-revised= dt-accepted= dt-pub-year=2006 dt-pub=200601 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Distribution of Electrons in Quantum Dots Analyzed by Classical Mapping and Molecular Dynamics en-subtitle= kn-subtitle= en-abstract= kn-abstract=The electron system of arbitrary degeneracy can be mapped onto a classical system where electrons of the same spin are assigned an additional interaction and the effect of degeneracy is taken into account through an imaginative temperature. We apply this method to electrons in quantum dots modeled as two-dimensional electron liquid confined in a finite domain by a harmonic potential. We analyze distribution functions by molecular dynamics instead of solving integral equations which are not so useful in the case without translational invariance. en-copyright= kn-copyright= en-aut-name=TakashiMiyake en-aut-sei=Takashi en-aut-mei=Miyake kn-aut-name=ŽO‘î—² kn-aut-sei=ŽO‘î kn-aut-mei=—² aut-affil-num=1 ORCID= en-aut-name=TotsujiChieko en-aut-sei=Totsuji en-aut-mei=Chieko kn-aut-name=“Œ’ÒçŽ}Žq kn-aut-sei=“Œ’Ò kn-aut-mei=çŽ}Žq aut-affil-num=2 ORCID= en-aut-name=TsurutaKenji en-aut-sei=Tsuruta en-aut-mei=Kenji kn-aut-name=’ß“cŒ’“ñ kn-aut-sei=’ß“c kn-aut-mei=Œ’“ñ aut-affil-num=3 ORCID= en-aut-name=TotsujiHiroo en-aut-sei=Totsuji en-aut-mei=Hiroo kn-aut-name=“Œ’Ò_•v kn-aut-sei=“Œ’Ò kn-aut-mei=_•v aut-affil-num=4 ORCID= affil-num=1 en-affil= kn-affil=Division of Industrial Innovation Sciences, Graduate School of Natural Science and Technology, Okayama University affil-num=2 en-affil= kn-affil=Division of Industrial Innovation Sciences, Graduate School of Natural Science and Technology, Okayama University affil-num=3 en-affil= kn-affil=Division of Industrial Innovation Sciences, Graduate School of Natural Science and Technology, Okayama University affil-num=4 en-affil= kn-affil=Division of Industrial Innovation Sciences, Graduate School of Natural Science and Technology, Okayama University END start-ver=1.4 cd-journal=joma no-vol=40 cd-vols= no-issue=1 article-no= start-page=36 end-page=39 dt-received= dt-revised= dt-accepted= dt-pub-year=2006 dt-pub=200601 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Stochastic-Dierence-Equation Method for Long Time-scale Molecular Dynamics Simulations en-subtitle= kn-subtitle= en-abstract= kn-abstract=We present a Stochastic-Difference-Equation (SDE) approach to long time-scale molecular dynamics (MD) simulations, which are required for nanosecond-scale phenomena. In this method, the MD trajectory in a fixed time period is obtained as a stationary solution of an action functional based on an error accumulation of the equation of motion along the path, thus reducing the problem to a boundary-value problem, instead of an initial-value problem in the ordinary MD method. We apply the method to formation processes of Cu thin film via nanocluster deposition onto a substrate. The applicability of the SDE algorithm to the problem and the effects of the choice of SDE parameters on the optimization processes of configuration pathway are examined. en-copyright= kn-copyright= en-aut-name=UchidaAtsushi en-aut-sei=Uchida en-aut-mei=Atsushi kn-aut-name=“à“cŒú kn-aut-sei=“à“c kn-aut-mei=Œú aut-affil-num=1 ORCID= en-aut-name=TotsujiChieko en-aut-sei=Totsuji en-aut-mei=Chieko kn-aut-name=“Œ’ÒçŽ}Žq kn-aut-sei=“Œ’Ò kn-aut-mei=çŽ}Žq aut-affil-num=2 ORCID= en-aut-name=TsurutaKenji en-aut-sei=Tsuruta en-aut-mei=Kenji kn-aut-name=’ß“cŒ’“ñ kn-aut-sei=’ß“c kn-aut-mei=Œ’“ñ aut-affil-num=3 ORCID= en-aut-name=TotsujiHiroo en-aut-sei=Totsuji en-aut-mei=Hiroo kn-aut-name=“Œ’Ò_•v kn-aut-sei=“Œ’Ò kn-aut-mei=_•v aut-affil-num=4 ORCID= affil-num=1 en-affil= kn-affil=Graduate School of Natural Science and Technology, Okayama University affil-num=2 en-affil= kn-affil=Graduate School of Natural Science and Technology, Okayama University affil-num=3 en-affil= kn-affil=Graduate School of Natural Science and Technology, Okayama University affil-num=4 en-affil= kn-affil=Graduate School of Natural Science and Technology, Okayama University END start-ver=1.4 cd-journal=joma no-vol=40 cd-vols= no-issue=1 article-no= start-page=31 end-page=35 dt-received= dt-revised= dt-accepted= dt-pub-year=2006 dt-pub=200601 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Melting of Spherical Yukawa Clusters Analyzed by Monte Carlo Simulation en-subtitle= kn-subtitle= en-abstract= kn-abstract=We analyze the melting of spherical Yukawa clusters by Monte Carlo simulations. Spherical clusters are expected to be found in dusty plasmas in an isotropic environment such as microgravity and serve as a model for classical clusters. We obtain the specific heat through fluctuations of the potential energy and identify its peak as the transition temperature. Melting temperatures are compared with those of bulk Yukawa systems and it is confirmed that the melting temperature increases and approaches the bulk value with the increase of the system size. en-copyright= kn-copyright= en-aut-name=OgawaTakafumi en-aut-sei=Ogawa en-aut-mei=Takafumi kn-aut-name=¬ì‹MŽj kn-aut-sei=¬ì kn-aut-mei=‹MŽj aut-affil-num=1 ORCID= en-aut-name=TotsujiChieko en-aut-sei=Totsuji en-aut-mei=Chieko kn-aut-name=“Œ’ÒçŽ}Žq kn-aut-sei=“Œ’Ò kn-aut-mei=çŽ}Žq aut-affil-num=2 ORCID= en-aut-name=TsurutaKenji en-aut-sei=Tsuruta en-aut-mei=Kenji kn-aut-name=’ß“cŒ’“ñ kn-aut-sei=’ß“c kn-aut-mei=Œ’“ñ aut-affil-num=3 ORCID= en-aut-name=TotsujiHiroo en-aut-sei=Totsuji en-aut-mei=Hiroo kn-aut-name=“Œ’Ò_•v kn-aut-sei=“Œ’Ò kn-aut-mei=_•v aut-affil-num=4 ORCID= affil-num=1 en-affil= kn-affil=Division of Industrial Innovation Sciences, Graduate School of Natural Science and Technology, Okayama University affil-num=2 en-affil= kn-affil=Division of Industrial Innovation Sciences, Graduate School of Natural Science and Technology, Okayama University affil-num=3 en-affil= kn-affil=Division of Industrial Innovation Sciences, Graduate School of Natural Science and Technology, Okayama University affil-num=4 en-affil= kn-affil=Division of Industrial Innovation Sciences, Graduate School of Natural Science and Technology, Okayama University END start-ver=1.4 cd-journal=joma no-vol=42 cd-vols= no-issue=1 article-no= start-page=44 end-page=47 dt-received= dt-revised= dt-accepted= dt-pub-year=2008 dt-pub=200801 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Vibrational Properties of Si Crystal with Vacancy : A Tight-Binding Study en-subtitle= kn-subtitle= en-abstract= kn-abstract=To analyze vibrational properties of Si crystal with a single charge-neutral vacancy, we perform large-scale simulations based on tight-binding molecular-dynamics method. Vibrational modes and frequencies are obtained by diagonalizing dynamical matrix within a harmonic approximation. Results indicate that there exist vibrational modes spatially localized around the vacancy and large frequency shifts associated with the localized modes contribute significantly to reduction of the vibrational free energy. en-copyright= kn-copyright= en-aut-name= en-aut-sei= en-aut-mei= kn-aut-name=OgawaTakafumi kn-aut-sei=Ogawa kn-aut-mei=Takafumi aut-affil-num=1 ORCID= en-aut-name=TsurutaKenji en-aut-sei=Tsuruta en-aut-mei=Kenji kn-aut-name=’ß“cŒ’“ñ kn-aut-sei=’ß“c kn-aut-mei=Œ’“ñ aut-affil-num=2 ORCID= en-aut-name=TotsujiChieko en-aut-sei=Totsuji en-aut-mei=Chieko kn-aut-name=“Œ’ÒçŽ}Žq kn-aut-sei=“Œ’Ò kn-aut-mei=çŽ}Žq aut-affil-num=3 ORCID= en-aut-name=TotsujiHiroo en-aut-sei=Totsuji en-aut-mei=Hiroo kn-aut-name=“Œ’Ò_•v kn-aut-sei=“Œ’Ò kn-aut-mei=_•v aut-affil-num=4 ORCID= en-aut-name= en-aut-sei= en-aut-mei= kn-aut-name=HiroshiIyetomi kn-aut-sei=Hiroshi kn-aut-mei=Iyetomi aut-affil-num=5 ORCID= affil-num=1 en-affil= kn-affil=Department of Electrical and Electronic Engineering Okayama University affil-num=2 en-affil= kn-affil=Department of Electrical and Electronic Engineering Okayama University affil-num=3 en-affil= kn-affil=Department of Electrical and Electronic Engineering Okayama University affil-num=4 en-affil= kn-affil=Department of Electrical and Electronic Engineering Okayama University affil-num=5 en-affil= kn-affil=Department of Physics Niigata University END start-ver=1.4 cd-journal=joma no-vol=42 cd-vols= no-issue=1 article-no= start-page=48 end-page=52 dt-received= dt-revised= dt-accepted= dt-pub-year=2008 dt-pub=200801 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Numerical Simulations of Two-dimensional Electron Fluid : An Application of Classical-map Hypernetted-chain Method en-subtitle= kn-subtitle= en-abstract= kn-abstract=Based on the mapping introduced by the classical-map hypernetted-chain (CHNC) method, classical numerical simulations, Monte Carlo and molecular dynamics, have been applied to the twodimensional electron fluid and the results are compared with those of quantum Monte Carlo simulations hitherto reported. It is shown that polarization properties of the ground state obtained by the diffusion Monte Carlo method are reproduced within the accuracy of quantum simulations by both of two mapping functions for the quantum temperature which have been proposed within the CHNC method. These results may serve as the basis of numerical simulations based on the CHNC method which are applicable to finite non-periodic systems like quantum dots and systems at finite temperatures. en-copyright= kn-copyright= en-aut-name=TotsujiChieko en-aut-sei=Totsuji en-aut-mei=Chieko kn-aut-name=“Œ’ÒçŽ}Žq kn-aut-sei=“Œ’Ò kn-aut-mei=çŽ}Žq aut-affil-num=1 ORCID= en-aut-name= en-aut-sei= en-aut-mei= kn-aut-name=MiyakeTakashi kn-aut-sei=Miyake kn-aut-mei=Takashi aut-affil-num=2 ORCID= en-aut-name= en-aut-sei= en-aut-mei= kn-aut-name=NakanishiKenta kn-aut-sei=Nakanishi kn-aut-mei=Kenta aut-affil-num=3 ORCID= en-aut-name=TsurutaKenji en-aut-sei=Tsuruta en-aut-mei=Kenji kn-aut-name=’ß“cŒ’“ñ kn-aut-sei=’ß“c kn-aut-mei=Œ’“ñ aut-affil-num=4 ORCID= en-aut-name=TotsujiHiroo en-aut-sei=Totsuji en-aut-mei=Hiroo kn-aut-name=“Œ’Ò_•v kn-aut-sei=“Œ’Ò kn-aut-mei=_•v aut-affil-num=5 ORCID= affil-num=1 en-affil= kn-affil=Graduate School of Natural Science and Technology and Faculty of Engineering, Okayama University affil-num=2 en-affil= kn-affil=Graduate School of Natural Science and Technology and Faculty of Engineering, Okayama University affil-num=3 en-affil= kn-affil=Graduate School of Natural Science and Technology and Faculty of Engineering, Okayama University affil-num=4 en-affil= kn-affil=Graduate School of Natural Science and Technology and Faculty of Engineering, Okayama University affil-num=5 en-affil= kn-affil=Graduate School of Natural Science and Technology and Faculty of Engineering, Okayama University END start-ver=1.4 cd-journal=joma no-vol=42 cd-vols= no-issue=1 article-no= start-page=56 end-page=59 dt-received= dt-revised= dt-accepted= dt-pub-year=2008 dt-pub=200801 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Spin Polarization of Two-Dimensional Electron System in a Finite Domain en-subtitle= kn-subtitle= en-abstract= kn-abstract=We analyze the ground state of the two-dimensional quantum system of electrons confined in a parabolic potential with the system size around 100. We map the system onto a classical system on the basis of the classical-map hypernetted-chain (CHNC) method which has been proven to work in the integral-equation-based analyses of uniform unbounded systems and then apply classical numerical simulations. We find that the confined system undergoes the transition to the spin polarized state with the decrease of the average density and the corresponding critical value is as low as rs ? 0.3 in terms of the usual rs parameter estimated for the average density. As the ground state for given value of the rs parameter, our data give the critical value for the transition around 20 which is consistent with the known possibility. The advantage of our method is a direct applicability to geometrically complex systems which are difficult to analyze by integral equations. The application to the structure like quantum dots reported here is the first example of such applications. en-copyright= kn-copyright= en-aut-name= en-aut-sei= en-aut-mei= kn-aut-name=MiyakeTakashi kn-aut-sei=Miyake kn-aut-mei=Takashi aut-affil-num=1 ORCID= en-aut-name=TotsujiChieko en-aut-sei=Totsuji en-aut-mei=Chieko kn-aut-name=“Œ’ÒçŽ}Žq kn-aut-sei=“Œ’Ò kn-aut-mei=çŽ}Žq aut-affil-num=2 ORCID= en-aut-name= en-aut-sei= en-aut-mei= kn-aut-name=NakanishiKenta kn-aut-sei=Nakanishi kn-aut-mei=Kenta aut-affil-num=3 ORCID= en-aut-name=TsurutaKenji en-aut-sei=Tsuruta en-aut-mei=Kenji kn-aut-name=’ß“cŒ’“ñ kn-aut-sei=’ß“c kn-aut-mei=Œ’“ñ aut-affil-num=4 ORCID= en-aut-name=TotsujiHiroo en-aut-sei=Totsuji en-aut-mei=Hiroo kn-aut-name=“Œ’Ò_•v kn-aut-sei=“Œ’Ò kn-aut-mei=_•v aut-affil-num=5 ORCID= affil-num=1 en-affil= kn-affil=Graduate School of Natural Science and Technology and Faculty of Engineering, Okayama University affil-num=2 en-affil= kn-affil=Graduate School of Natural Science and Technology and Faculty of Engineering, Okayama University affil-num=3 en-affil= kn-affil=Graduate School of Natural Science and Technology and Faculty of Engineering, Okayama University affil-num=4 en-affil= kn-affil=Graduate School of Natural Science and Technology and Faculty of Engineering, Okayama University affil-num=5 en-affil= kn-affil=Graduate School of Natural Science and Technology and Faculty of Engineering, Okayama University END start-ver=1.4 cd-journal=joma no-vol=43 cd-vols= no-issue= article-no= start-page=8 end-page=15 dt-received= dt-revised= dt-accepted= dt-pub-year=2009 dt-pub=200901 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Dispersion Models and Electromagnetic FDTD Analyses of Nanostructured Metamaterials using Parallel Computer en-subtitle= kn-subtitle= en-abstract= kn-abstract=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. en-copyright= kn-copyright= en-aut-name= en-aut-sei= en-aut-mei= kn-aut-name=UmedaRyosuke kn-aut-sei=Umeda kn-aut-mei=Ryosuke aut-affil-num=1 ORCID= en-aut-name=TotsujiChieko en-aut-sei=Totsuji en-aut-mei=Chieko kn-aut-name=“Œ’ÒçŽ}Žq kn-aut-sei=“Œ’Ò kn-aut-mei=çŽ}Žq aut-affil-num=2 ORCID= en-aut-name=TsurutaKenji en-aut-sei=Tsuruta en-aut-mei=Kenji kn-aut-name=’ß“cŒ’“ñ kn-aut-sei=’ß“c kn-aut-mei=Œ’“ñ aut-affil-num=3 ORCID= en-aut-name=TotsujiHiroo en-aut-sei=Totsuji en-aut-mei=Hiroo kn-aut-name=“Œ’Ò_•v kn-aut-sei=“Œ’Ò kn-aut-mei=_•v aut-affil-num=4 ORCID= affil-num=1 en-affil= kn-affil=Graduate School of Natural Science and Technology Okayama University affil-num=2 en-affil= kn-affil=Graduate School of Natural Science and Technology Okayama University affil-num=3 en-affil= kn-affil=Graduate School of Natural Science and Technology Okayama University affil-num=4 en-affil= kn-affil=Graduate School of Natural Science and Technology Okayama University END start-ver=1.4 cd-journal=joma no-vol=43 cd-vols= no-issue= article-no= start-page=16 end-page=21 dt-received= dt-revised= dt-accepted= dt-pub-year=2009 dt-pub=200901 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=FDTD Simulations of Acoustic Waves in Two-Dimensional Phononic Crystals using Parallel Computer en-subtitle= kn-subtitle= en-abstract= kn-abstract=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 acousticglens effecthwith the slab appears due to the negative refractions. The relationship between the focal intensity in the lens effect and the band structure is discussed. en-copyright= kn-copyright= en-aut-name= en-aut-sei= en-aut-mei= kn-aut-name=KuroseTomoyuki kn-aut-sei=Kurose kn-aut-mei=Tomoyuki aut-affil-num=1 ORCID= en-aut-name=TsurutaKenji en-aut-sei=Tsuruta en-aut-mei=Kenji kn-aut-name=’ß“cŒ’“ñ kn-aut-sei=’ß“c kn-aut-mei=Œ’“ñ aut-affil-num=2 ORCID= en-aut-name=TotsujiChieko en-aut-sei=Totsuji en-aut-mei=Chieko kn-aut-name=“Œ’ÒçŽ}Žq kn-aut-sei=“Œ’Ò kn-aut-mei=çŽ}Žq aut-affil-num=3 ORCID= en-aut-name=TotsujiHiroo en-aut-sei=Totsuji en-aut-mei=Hiroo kn-aut-name=“Œ’Ò_•v kn-aut-sei=“Œ’Ò kn-aut-mei=_•v aut-affil-num=4 ORCID= affil-num=1 en-affil= kn-affil=Graduate School of Natural Science and Technology Okayama University affil-num=2 en-affil= kn-affil=Graduate School of Natural Science and Technology Okayama University affil-num=3 en-affil= kn-affil=Graduate School of Natural Science and Technology Okayama University affil-num=4 en-affil= kn-affil=Graduate School of Natural Science and Technology Okayama University END start-ver=1.4 cd-journal=joma no-vol=43 cd-vols= no-issue= article-no= start-page=22 end-page=26 dt-received= dt-revised= dt-accepted= dt-pub-year=2009 dt-pub=200901 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Information Transfer and Entanglement Creation by Spin Chains: Effects of Noise and Asymmetry en-subtitle= kn-subtitle= en-abstract= kn-abstract=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. en-copyright= kn-copyright= en-aut-name=TotsujiHiroo en-aut-sei=Totsuji en-aut-mei=Hiroo kn-aut-name=“Œ’Ò_•v kn-aut-sei=“Œ’Ò kn-aut-mei=_•v aut-affil-num=1 ORCID= en-aut-name= en-aut-sei= en-aut-mei= kn-aut-name=ChaiHong kn-aut-sei=Chai kn-aut-mei=Hong aut-affil-num=2 ORCID= en-aut-name=TotsujiChieko en-aut-sei=Totsuji en-aut-mei=Chieko kn-aut-name=“Œ’ÒçŽ}Žq kn-aut-sei=“Œ’Ò kn-aut-mei=çŽ}Žq aut-affil-num=3 ORCID= en-aut-name=TsurutaKenji en-aut-sei=Tsuruta en-aut-mei=Kenji kn-aut-name=’ß“cŒ’“ñ kn-aut-sei=’ß“c kn-aut-mei=Œ’“ñ aut-affil-num=4 ORCID= affil-num=1 en-affil= kn-affil=Graduate School of Natural Science and Technology, Okayama University affil-num=2 en-affil= kn-affil=Graduate School of Natural Science and Technology, Okayama University affil-num=3 en-affil= kn-affil=Graduate School of Natural Science and Technology, Okayama University affil-num=4 en-affil= kn-affil=Graduate School of Natural Science and Technology, Okayama University END