| JaLCDOI | 10.18926/20012 |
|---|---|
| FullText URL | Mem_Fac_Eng_OU_29_1_15.pdf |
| Author | Totsuji, Chieko| Matsubara, Takeo| Obuchi, Masumi| |
| 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. |
| Publication Title | Memoirs of the Faculty of Engineering, Okayama University |
| Published Date | 1994-11-30 |
| Volume | volume29 |
| Issue | issue1 |
| Start Page | 15 |
| End Page | 22 |
| ISSN | 0475-0071 |
| language | 英語 |
| File Version | publisher |
| NAID | 120002310919 |
| JaLCDOI | 10.18926/20011 |
|---|---|
| FullText URL | Mem_Fac_Eng_OU_29_1_7.pdf |
| Author | Hiroyuki Tachibana| Totsuji, Hiroo| Nara, Shigetoshi| Totsuji, Chieko| |
| 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. |
| Publication Title | Memoirs of the Faculty of Engineering, Okayama University |
| Published Date | 1994-11-30 |
| Volume | volume29 |
| Issue | issue1 |
| Start Page | 7 |
| End Page | 14 |
| ISSN | 0475-0071 |
| language | 英語 |
| File Version | publisher |
| NAID | 120002310741 |
| JaLCDOI | 10.18926/19674 |
|---|---|
| FullText URL | Mem_Fac_Eng_OU_33_2_71.pdf |
| Author | Tsuruta, Kenji| Totsuji, Hiroo| Totsuji, Chieko| |
| 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. |
| Publication Title | Memoirs of the Faculty of Engineering, Okayama University |
| Published Date | 1999-04-27 |
| Volume | volume33 |
| Issue | issue2 |
| Start Page | 71 |
| End Page | 77 |
| ISSN | 0475-0071 |
| language | 英語 |
| File Version | publisher |
| NAID | 120002309027 |
| JaLCDOI | 10.18926/19673 |
|---|---|
| FullText URL | Mem_Fac_Eng_OU_33_2_61.pdf |
| Author | Totsuji, Hiroo| Tsuruta, Kenji| Totsuji, Chieko| |
| 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. |
| Publication Title | Memoirs of the Faculty of Engineering, Okayama University |
| Published Date | 1999-04-27 |
| Volume | volume33 |
| Issue | issue2 |
| Start Page | 61 |
| End Page | 69 |
| ISSN | 0475-0071 |
| language | 英語 |
| File Version | publisher |
| NAID | 120002309106 |
| JaLCDOI | 10.18926/19671 |
|---|---|
| FullText URL | Mem_Fac_Eng_OU_33_2_51.pdf |
| Author | Totsuji, Hiroo| Tsuruta, Kenji| Totsuji, Chieko| |
| 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 γ(s), we have increasingly strong screening of proton charge by electrons and the decrease of electron density in the domain between protons. |
| Publication Title | Memoirs of the Faculty of Engineering, Okayama University |
| Published Date | 1999-04-27 |
| Volume | volume33 |
| Issue | issue2 |
| Start Page | 51 |
| End Page | 59 |
| ISSN | 0475-0071 |
| language | 英語 |
| File Version | publisher |
| NAID | 120002309192 |
| JaLCDOI | 10.18926/19637 |
|---|---|
| FullText URL | Mem_Fac_Eng_OU_32_43.pdf |
| Author | Totsuji, Chieko| Matsubara Takeo| |
| 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. |
| Publication Title | Memoirs of the Faculty of Engineering, Okayama University |
| Published Date | 1998-04-20 |
| Volume | volume32 |
| Issue | issue1-2 |
| Start Page | 43 |
| End Page | 54 |
| ISSN | 0475-0071 |
| language | 英語 |
| File Version | publisher |
| NAID | 120002309098 |
| JaLCDOI | 10.18926/19636 |
|---|---|
| FullText URL | Mem_Fac_Eng_OU_32_23.pdf |
| Author | Totsuji, Hiroo| Kishimoto, Tokunari| Totsuji, Chieko| |
| 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. |
| Publication Title | Memoirs of the Faculty of Engineering, Okayama University |
| Published Date | 1998-04-20 |
| Volume | volume32 |
| Issue | issue1-2 |
| Start Page | 23 |
| End Page | 41 |
| ISSN | 0475-0071 |
| language | 英語 |
| File Version | publisher |
| NAID | 120002309150 |
| JaLCDOI | 10.18926/17831 |
|---|---|
| FullText URL | Mem_Fac_Eng_OU_43_22.pdf |
| Author | Totsuji, Hiroo| Chai Hong| Totsuji, Chieko| Tsuruta, Kenji| |
| 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. |
| Publication Title | Memoirs of the Faculty of Engineering, Okayama University |
| Published Date | 2009-01 |
| Volume | volume43 |
| Start Page | 22 |
| End Page | 26 |
| ISSN | 1349-6115 |
| language | 英語 |
| File Version | publisher |
| NAID | 120002308966 |
| JaLCDOI | 10.18926/17829 |
|---|---|
| FullText URL | Mem_Fac_Eng_OU_43_16.pdf |
| Author | Kurose Tomoyuki| Tsuruta, Kenji| Totsuji, Chieko| Totsuji, Hiroo| |
| 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 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. |
| Publication Title | Memoirs of the Faculty of Engineering, Okayama University |
| Published Date | 2009-01 |
| Volume | volume43 |
| Start Page | 16 |
| End Page | 21 |
| ISSN | 1349-6115 |
| language | 英語 |
| File Version | publisher |
| NAID | 120002308928 |
| JaLCDOI | 10.18926/17826 |
|---|---|
| FullText URL | Mem_Fac_Eng_OU_43_8.pdf |
| Author | Umeda Ryosuke| Totsuji, Chieko| Tsuruta, Kenji| Totsuji, Hiroo| |
| 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. |
| Publication Title | Memoirs of the Faculty of Engineering, Okayama University |
| Published Date | 2009-01 |
| Volume | volume43 |
| Start Page | 8 |
| End Page | 15 |
| ISSN | 1349-6115 |
| language | 英語 |
| File Version | publisher |
| NAID | 120002308833 |
| JaLCDOI | 10.18926/15461 |
|---|---|
| FullText URL | Mem_Fac_Eng_OU_28_2_53.pdf |
| Author | Totsuji, Chieko| Matsubara Takeo| Miyata Satoru| |
| 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. |
| Publication Title | Memoirs of the Faculty of Engineering, Okayama University |
| Published Date | 1994-03-15 |
| Volume | volume28 |
| Issue | issue2 |
| Start Page | 53 |
| End Page | 58 |
| ISSN | 0475-0071 |
| language | 英語 |
| File Version | publisher |
| NAID | 120002307223 |
| JaLCDOI | 10.18926/15435 |
|---|---|
| FullText URL | Mem_Fac_Eng_OU_28_1_39.pdf |
| Author | Totsuji, Chieko| Matsubara Takeo| |
| 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. |
| Publication Title | Memoirs of the Faculty of Engineering, Okayama University |
| Published Date | 1993-11-30 |
| Volume | volume28 |
| Issue | issue1 |
| Start Page | 39 |
| End Page | 50 |
| ISSN | 0475-0071 |
| language | 英語 |
| File Version | publisher |
| NAID | 120002307179 |
| JaLCDOI | 10.18926/15424 |
|---|---|
| FullText URL | Mem_Fac_Eng_OU_29_2_67.pdf |
| Author | Totsuji, Chieko| Matsubara Takeo| Obuchi Masumi| |
| Abstract | The π-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. |
| Publication Title | Memoirs of the Faculty of Engineering, Okayama University |
| Published Date | 1995-03-27 |
| Volume | volume29 |
| Issue | issue2 |
| Start Page | 67 |
| End Page | 76 |
| ISSN | 0475-0071 |
| language | 英語 |
| File Version | publisher |
| NAID | 120002307408 |
| JaLCDOI | 10.18926/15405 |
|---|---|
| FullText URL | Mem_Fac_Eng_OU_30_2_39.pdf |
| Author | Totsuji, Chieko| |
| 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. |
| Publication Title | Memoirs of the Faculty of Engineering, Okayama University |
| Published Date | 1996-03-29 |
| Volume | volume30 |
| Issue | issue2 |
| Start Page | 39 |
| End Page | 43 |
| ISSN | 0475-0071 |
| language | 英語 |
| File Version | publisher |
| NAID | 120002307769 |
| JaLCDOI | 10.18926/15402 |
|---|---|
| FullText URL | Mem_Fac_Eng_OU_30_2_27.pdf |
| Author | Totsuji, Hiroo| Kishimoto, Tokunari| Totsuji, Chieko| |
| 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. |
| Publication Title | Memoirs of the Faculty of Engineering, Okayama University |
| Published Date | 1996-03-29 |
| Volume | volume30 |
| Issue | issue2 |
| Start Page | 27 |
| End Page | 37 |
| ISSN | 0475-0071 |
| language | 英語 |
| File Version | publisher |
| NAID | 120002307582 |
| JaLCDOI | 10.18926/15383 |
|---|---|
| FullText URL | Mem_Fac_Eng_OU_30_1_89.pdf |
| Author | Totsuji, Chieko| Sanaka Yoshiaki| Totsuji, Hiroo| |
| 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. |
| Publication Title | Memoirs of the Faculty of Engineering, Okayama University |
| Published Date | 1995-12-28 |
| Volume | volume30 |
| Issue | issue1 |
| Start Page | 89 |
| End Page | 97 |
| ISSN | 0475-0071 |
| language | 英語 |
| File Version | publisher |
| NAID | 120002307957 |
| JaLCDOI | 10.18926/15381 |
|---|---|
| FullText URL | Mem_Fac_Eng_OU_30_1_75.pdf |
| Author | Totsuji, Hiroo| Inoue, Yoshihiko| Kishimoto, Tokunari| Totsuji, Chieko| Nara, Shigetoshi| |
| 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. |
| Publication Title | Memoirs of the Faculty of Engineering, Okayama University |
| Published Date | 1995-12-28 |
| Volume | volume30 |
| Issue | issue1 |
| Start Page | 75 |
| End Page | 87 |
| ISSN | 0475-0071 |
| language | 英語 |
| File Version | publisher |
| NAID | 120002307479 |
| JaLCDOI | 10.18926/15361 |
|---|---|
| FullText URL | Mem_Fac_Eng_OU_35_77.pdf |
| Author | Kishimoto Tokunari| Totsuji, Chieko| Tsuruta, Kenji| Totsuji, Hiroo| |
| 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. |
| Publication Title | Memoirs of the Faculty of Engineering, Okayama University |
| Published Date | 2001-03-27 |
| Volume | volume35 |
| Issue | issue1-2 |
| Start Page | 77 |
| End Page | 95 |
| ISSN | 0475-0071 |
| language | 英語 |
| File Version | publisher |
| NAID | 120002307940 |
| JaLCDOI | 10.18926/15358 |
|---|---|
| FullText URL | Mem_Fac_Eng_OU_35_63.pdf |
| Author | Shinomiya Shigeru| Totsuji, Chieko| Tsuruta, Kenji| Totsuji, Hiroo| |
| 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. |
| Publication Title | Memoirs of the Faculty of Engineering, Okayama University |
| Published Date | 2001-03-27 |
| Volume | volume35 |
| Issue | issue1-2 |
| Start Page | 63 |
| End Page | 75 |
| ISSN | 0475-0071 |
| language | 英語 |
| File Version | publisher |
| NAID | 120002307673 |
| JaLCDOI | 10.18926/15166 |
|---|---|
| FullText URL | Mem_Fac_Eng_OU_31_1_19.pdf |
| Author | Totsuji, Hiroo| Kishimoto, Tokunari| Totsuji, Chieko| |
| 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. |
| Publication Title | Memoirs of the Faculty of Engineering, Okayama University |
| Published Date | 1996-12-27 |
| Volume | volume31 |
| Issue | issue1 |
| Start Page | 19 |
| End Page | 33 |
| ISSN | 0475-0071 |
| language | 英語 |
| File Version | publisher |
| NAID | 120002307616 |
