| JaLCDOI | 10.18926/14121 |
|---|---|
| フルテキストURL | Mem_Fac_Eng_OU_40_1_40.pdf |
| 著者 | 三宅 隆| 東辻 千枝子| 鶴田 健二| 東辻 浩夫| |
| 抄録 | 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. |
| 出版物タイトル | Memoirs of the Faculty of Engineering, Okayama University |
| 発行日 | 2006-01 |
| 巻 | 40巻 |
| 号 | 1号 |
| 開始ページ | 40 |
| 終了ページ | 43 |
| ISSN | 0475-0071 |
| 言語 | 英語 |
| 論文のバージョン | publisher |
| NAID | 120002308268 |
| JaLCDOI | 10.18926/14119 |
|---|---|
| フルテキストURL | Mem_Fac_Eng_OU_40_1_31.pdf |
| 著者 | 小川 貴史| 東辻 千枝子| 鶴田 健二| 東辻 浩夫| |
| 抄録 | 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. |
| 出版物タイトル | Memoirs of the Faculty of Engineering, Okayama University |
| 発行日 | 2006-01 |
| 巻 | 40巻 |
| 号 | 1号 |
| 開始ページ | 31 |
| 終了ページ | 35 |
| ISSN | 0475-0071 |
| 言語 | 英語 |
| 論文のバージョン | publisher |
| NAID | 120002308329 |
| 著者 | Totsuji, Hiroo| Ogawa, Takafumi| Totsuji, Chieko| Tsuruta, Kenji| |
|---|---|
| 発行日 | 2005-9 |
| 出版物タイトル | Physical Review E |
| 巻 | 72巻 |
| 号 | 3号 |
| 資料タイプ | 学術雑誌論文 |
| 著者 | Totsuji, Hiroo| Totsuji, Chieko| Ogawa, Takafumi| Tsuruta, Kenji| |
|---|---|
| 発行日 | 2005-4 |
| 出版物タイトル | Physical Review E |
| 巻 | 71巻 |
| 号 | 4号 |
| 資料タイプ | 学術雑誌論文 |
| JaLCDOI | 10.18926/14150 |
|---|---|
| フルテキストURL | Mem_Fac_Eng_39_1_46.pdf |
| 著者 | 門野 恵典| 東辻 千枝子| 鶴田 健二| 東辻 浩夫| |
| 抄録 | 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. |
| 出版物タイトル | Memoirs of the Faculty of Engineering, Okayama University |
| 発行日 | 2005-01 |
| 巻 | 39巻 |
| 号 | 1号 |
| 開始ページ | 46 |
| 終了ページ | 51 |
| ISSN | 0475-0071 |
| 言語 | 英語 |
| 論文のバージョン | publisher |
| NAID | 120002308231 |
| JaLCDOI | 10.18926/14152 |
|---|---|
| フルテキストURL | Mem_Fac_Eng_39_1_52.pdf |
| 著者 | 金森 克也| 東辻 千枝子| 鶴田 健二| 東辻 浩夫| |
| 抄録 | 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. |
| 出版物タイトル | Memoirs of the Faculty of Engineering, Okayama University |
| 発行日 | 2005-01 |
| 巻 | 39巻 |
| 号 | 1号 |
| 開始ページ | 52 |
| 終了ページ | 55 |
| ISSN | 0475-0071 |
| 言語 | 英語 |
| 論文のバージョン | publisher |
| NAID | 120002308445 |
| 著者 | Totsuji, Hiroo| Liman, M. Sanusi| Totsuji, Chieko| Tsuruta, Kenji| |
|---|---|
| 発行日 | 2004-7 |
| 出版物タイトル | Physical Review E |
| 巻 | 70巻 |
| 号 | 1号 |
| 資料タイプ | 学術雑誌論文 |
| JaLCDOI | 10.18926/46949 |
|---|---|
| フルテキストURL | mfe_38_1-2_029_032.pdf |
| 著者 | Totsuji, Hiroo| Totsuji, Chieko| Ogawa, Takafumi| Tsuruta, Kenji| |
| 抄録 | 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. |
| 出版物タイトル | Memoirs of the Faculty of Engineering, Okayama University |
| 発行日 | 2004-03 |
| 巻 | 38巻 |
| 号 | 1-2号 |
| 開始ページ | 29 |
| 終了ページ | 32 |
| ISSN | 0475-0071 |
| 言語 | 英語 |
| 論文のバージョン | publisher |
| NAID | 80016863328 |
| JaLCDOI | 10.18926/46950 |
|---|---|
| フルテキストURL | mfe_38_1-2_033_037.pdf |
| 著者 | Liman, M. Sanusi| Totsuji, Chieko| Tsuruta, Kenji| Totsuji, Hiroo| |
| 抄録 | 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. |
| 出版物タイトル | Memoirs of the Faculty of Engineering, Okayama University |
| 発行日 | 2004-03 |
| 巻 | 38巻 |
| 号 | 1-2号 |
| 開始ページ | 33 |
| 終了ページ | 37 |
| ISSN | 0475-0071 |
| 言語 | 英語 |
| 論文のバージョン | publisher |
| NAID | 80016863329 |
| JaLCDOI | 10.18926/46968 |
|---|---|
| フルテキストURL | mfe_37_1_011_014.pdf |
| 著者 | Totsuji, Chieko| Limant, Muhammad S.| Tsuruta, Kenji| Totsuji, Hiroo| |
| 抄録 | 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. |
| 出版物タイトル | Memoirs of the Faculty of Engineering, Okayama University |
| 発行日 | 2002-11 |
| 巻 | 37巻 |
| 号 | 1号 |
| 開始ページ | 11 |
| 終了ページ | 14 |
| ISSN | 0475-0071 |
| 言語 | 英語 |
| 論文のバージョン | publisher |
| NAID | 80015784816 |
| JaLCDOI | 10.18926/46999 |
|---|---|
| フルテキストURL | mfe_36_1_041_049.pdf |
| 著者 | Totsuji, Hiroo| Kishimoto, Tokunari| Totsuji, Chieko| Tsuruta, Kenji| |
| 抄録 | 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. |
| 出版物タイトル | Memoirs of the Faculty of Engineering, Okayama University |
| 発行日 | 2001-12 |
| 巻 | 36巻 |
| 号 | 1号 |
| 開始ページ | 41 |
| 終了ページ | 49 |
| ISSN | 0475-0071 |
| 言語 | 英語 |
| 論文のバージョン | publisher |
| NAID | 80015112663 |
| JaLCDOI | 10.18926/15358 |
|---|---|
| フルテキストURL | Mem_Fac_Eng_OU_35_63.pdf |
| 著者 | Shinomiya Shigeru| 東辻 千枝子| 鶴田 健二| 東辻 浩夫| |
| 抄録 | 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. |
| 出版物タイトル | Memoirs of the Faculty of Engineering, Okayama University |
| 発行日 | 2001-03-27 |
| 巻 | 35巻 |
| 号 | 1-2号 |
| 開始ページ | 63 |
| 終了ページ | 75 |
| ISSN | 0475-0071 |
| 言語 | 英語 |
| 論文のバージョン | publisher |
| NAID | 120002307673 |
| JaLCDOI | 10.18926/15361 |
|---|---|
| フルテキストURL | Mem_Fac_Eng_OU_35_77.pdf |
| 著者 | Kishimoto Tokunari| 東辻 千枝子| 鶴田 健二| 東辻 浩夫| |
| 抄録 | 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. |
| 出版物タイトル | Memoirs of the Faculty of Engineering, Okayama University |
| 発行日 | 2001-03-27 |
| 巻 | 35巻 |
| 号 | 1-2号 |
| 開始ページ | 77 |
| 終了ページ | 95 |
| ISSN | 0475-0071 |
| 言語 | 英語 |
| 論文のバージョン | publisher |
| NAID | 120002307940 |
| JaLCDOI | 10.18926/19671 |
|---|---|
| フルテキストURL | Mem_Fac_Eng_OU_33_2_51.pdf |
| 著者 | 東辻 浩夫| 鶴田 健二| 東辻 千枝子| |
| 抄録 | 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. |
| 出版物タイトル | Memoirs of the Faculty of Engineering, Okayama University |
| 発行日 | 1999-04-27 |
| 巻 | 33巻 |
| 号 | 2号 |
| 開始ページ | 51 |
| 終了ページ | 59 |
| ISSN | 0475-0071 |
| 言語 | 英語 |
| 論文のバージョン | publisher |
| NAID | 120002309192 |
| JaLCDOI | 10.18926/19673 |
|---|---|
| フルテキストURL | Mem_Fac_Eng_OU_33_2_61.pdf |
| 著者 | 東辻 浩夫| 鶴田 健二| 東辻 千枝子| |
| 抄録 | 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. |
| 出版物タイトル | Memoirs of the Faculty of Engineering, Okayama University |
| 発行日 | 1999-04-27 |
| 巻 | 33巻 |
| 号 | 2号 |
| 開始ページ | 61 |
| 終了ページ | 69 |
| ISSN | 0475-0071 |
| 言語 | 英語 |
| 論文のバージョン | publisher |
| NAID | 120002309106 |
| JaLCDOI | 10.18926/19674 |
|---|---|
| フルテキストURL | Mem_Fac_Eng_OU_33_2_71.pdf |
| 著者 | 鶴田 健二| 東辻 浩夫| 東辻 千枝子| |
| 抄録 | 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. |
| 出版物タイトル | Memoirs of the Faculty of Engineering, Okayama University |
| 発行日 | 1999-04-27 |
| 巻 | 33巻 |
| 号 | 2号 |
| 開始ページ | 71 |
| 終了ページ | 77 |
| ISSN | 0475-0071 |
| 言語 | 英語 |
| 論文のバージョン | publisher |
| NAID | 120002309027 |