研究者詳細 - 鶴田　健二

MISC - 鶴田　健二

分割表示 166 件中 121 - 140 件目／全件表示 >>

Structures of Confined Yukawa System with and without Gravity

C. Totsuji, T. Kishimoto, K. Tsuruta, H. Totsuji

Proceedings of the International Congress on Plasma Physics 2000 2001年

Initial stages of sintering of TiO2 nanoparticles: Variable-charge molecular dynamics simulations

S. Ogata, H. Iyetomi, K. Tsuruta, F. Shimojo, A. Nakano, P. Vashishta, R. K. Kalia, C.-K. Loong

Mat. Res. Soc. Symp. Proc. 2001年

Parallel Tight-Binding Simulations of Nanophase Ceramics: Atomic and Electronic Transport at Grain Boundaries

K. Tsuruta, H. Totsuji, C. Totsuji

Mat. Res. Soc. Symp. Proc. 2001年

ナノ材料シミュレーションの最近の展開

家富洋, 尾形修司, 菊池英明, 下條冬樹, 鶴田健二, 中野愛一郎, R. K. Kalia, P. Vashishta

マテリアルインテグレーション Vol. 14 No. 1, pp.3-8 2001年

25pXG-1 閉じこめられた湯川系: 微小重力下の一成分および多成分系のシミュレーションと理論

東辻浩夫, 岸本篤也, 鶴田健二, 東辻千枝子

日本物理学会講演概要集 55 ( 2 ) 190 - 190 2000年9月

25pYP-10 電荷可変分子動力学シミュレーションによるナノフェーズTiO2の構造と空間電荷分布

家富洋, 尾形修司, 鶴田健二, 下條冬樹

日本物理学会講演概要集 55 ( 2 ) 860 - 860 2000年9月

25pYP-8 TBMD法による炭化珪素ナノ微粒子の焼結シミュレーション : 微粒子間相対運動と原子拡散

鶴田健二, 東辻浩夫, 東辻千枝子

日本物理学会講演概要集 55 ( 2 ) 859 - 859 2000年9月

22aB-2 水素プラズマの量子シミュレーション : 並列化とその効率

鶴田健二, 上島豊, 千原順三, 田島俊樹, 西井良和, 東辻千技子, 東辻浩夫

日本物理学会講演概要集 55 ( 1 ) 129 - 129 2000年3月

22aB-1 水素プラズマの量子シミュレーション : 熱力学的特性

西井良和, 東辻千技子, 鶴田健二, 東辻浩夫, 上島豊, 千原順三, 田島俊樹

日本物理学会講演概要集 55 ( 1 ) 129 - 129 2000年3月

23aD-11 2次元ダスト結晶の構造と融解 (2)

賀門健一, 岸本篤也, 東辻千枝子, 鶴田健二, 東辻浩夫

日本物理学会講演概要集 55 ( 1 ) 153 - 153 2000年3月

23aD-6 ペニングトラップ中の多成分荷電粒子系 : 10^5粒子並列分子動力学計算

岸本篤也, 中野孝一, 東辻千枝子, 鶴田健二, 東辻浩夫

日本物理学会講演概要集 55 ( 1 ) 152 - 152 2000年3月

23aD-7 ペニングトラップ中の多成分荷電粒子系 : 強磁場中の分布の緩和

東辻浩夫, 岸本篤也, 鶴田健二, 東辻千枝子

日本物理学会講演概要集 55 ( 1 ) 152 - 152 2000年3月

24pY-12 非直交タイトバインディング法によるSi/Geの解析

四宮茂, 東辻千枝子, 鶴田健二, 東辻浩夫

日本物理学会講演概要集 55 ( 1 ) 857 - 857 2000年3月

25aY-5 二酸化チタン・ナノ微粒子の結合過程シミュレーション : 表面電荷層の効果

家富洋, 尾形修司, 鶴田健二, 下條冬樹, Kalia Rajiv K., Nakano Aiichiro, Vashishta priya

日本物理学会講演概要集 55 ( 1 ) 864 - 864 2000年3月

25aY-7 炭化珪素のTBMD計算 : 微粒子焼結とTBパラメータ抽出

鶴田健二, 東辻浩夫, 東辻千枝子, 香山正憲

日本物理学会講演概要集 55 ( 1 ) 865 - 865 2000年3月

Variable-charge molecular dynamics of aggregation of TiO2 nanocrystals

S Ogata, H Iyetomi, K Tsuruta, F Shimojo, A Nakano, RK Kalia, P Vashishta

GRAIN BOUNDARY ENGINEERING IN CERAMICS - FROM GRAIN BOUNDARY PHENOMENA TO GRAIN BOUNDARY QUANTUM STRUCTURES 118 79 - 86 2000年

記述言語：英語出版者・発行元：AMER CERAMIC SOC

Molecular dynamics (MD) simulations of both rutile and anatase TiO2-nanoclusters (size 60-80 Angstrom) are performed using an environment-dependent interatomic potential developed recently by Ogata et al. [J. Appl. Phys. 86 [16], 3036-3041 (1999)]. In the potential, atomic charges vary dynamically according to the generalized electronegativity-equalization principle. Formation of double-charge layer and enhanced atomic diffusion are observed in surface regions of the free TiO2-nanospheres by inclusion of the atomic-charge variation. Their effects on aggregation processes of TiO2 nanoclusters are investigated through MD simulations.

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Tight-binding molecular dynamics of ceramic nanocrystals using parallel PC cluster

K Tsuruta, H Totsuji, C Totsuji

GRAIN BOUNDARY ENGINEERING IN CERAMICS - FROM GRAIN BOUNDARY PHENOMENA TO GRAIN BOUNDARY QUANTUM STRUCTURES 118 33 - 39 2000年

記述言語：英語出版者・発行元：AMER CERAMIC SOC

Tight-binding molecular dynamics (TBMD) simulations are performed to study atomistic/electronic structures and electronic transport in nanocrystalline silicon-carbide ceramic (nc-SiC). The simulations are based on an O(N) algorithm (the Fermi-operator expansion method) for calculating electronic contributions in the energy and forces. The code has been fully parallelized on our Pentium-based parallel machines.
In a sintering simulation of aligned (no tilt or twist) SiC nanocrystals at T approximate to 730 degreesC, we find that a neck is formed promptly without formation of defects. Analyses reveal that unsaturated bonds exist only in grain surfaces accompanying the gap states. In the case of tilted (< 122 >) nanocrystals, surface structures formed before sintering affect significantly the grain-boundary formation. An electrical conductivity of the sintered (aligned) nc-SiC system is estimated via the Kubo-Greenwood formula with tight-binding representation. Effects of surface states on the conductivity is analyzed.

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Intercluster interaction of TiO2 nanoclusters using variable-charge interatomic potentials

S Ogata, H Iyetomi, K Tsuruta, F Shimojo, RK Kalia, A Nakano, P Vashishta

NANOPHASE AND NANOCOMPOSITE MATERIALS III 581 667 - 672 2000年

記述言語：英語出版者・発行元：MATERIALS RESEARCH SOCIETY

A new interatomic potential has been developed for molecular-dynamics simulations of TiO2 based on the formalism of Streitz and Mintmire [J. Adhesion Sci. Technol. 8, 853 (1994)], in which atomic charges vary dynamically according to the generalized electronegativity-equalization principle. The present potential reproduces various quantities of rutile crystal including vibrational density of states, static dielectric constants, melting temperature, elastic moduli, and surface relaxation. Calculated cohesive-energy and dielectric constants for anatase crystal agree well with experimental data The potential is applied to TiO2 nanoclusters (size 60-80 Angstrom) for both anatase and rutile phases to analyze their equilibrium configuration and space-charge distribution. Stable double-charge layer is found in the surface region of a spherical nanocluster for both rutile and anatase, resulting in enhanced Coulomb-repulsion between the nanoclusters at close proximity.

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Tight-binding molecular dynamics of ceramic nanocrystals using PC-based parallel machines

K Tsuruta, H Totsuji, C Totsuji

NANOPHASE AND NANOCOMPOSITE MATERIALS III 581 673 - 678 2000年

記述言語：英語出版者・発行元：MATERIALS RESEARCH SOCIETY

Evolution of atomic and electronic structures of silicon-carbide (SiC) nanocrystals during sintering is investigated by a tight-binding molecular dynamics (TBMD) method. An O(N) algorithm (the Fermi-operator expansion method) is employed for calculating electronic contributions in the energy and forces. Simulations are performed on our eight-node parallel PC cluster. In a sintering simulation of aligned (no tilt or twist) SiC nanocrystals at T=1000K we find that a neck is formed promptly without formation of defects. Analyses of local electronic density-of-states (DOS) and effective charges reveal that unsaturated bonds exist only in grain surfaces accompanying the gap states. In the case of tilted (<122>) nanocrystals, surface structures formed before sintering affect significantly the grain-boundary formation.

Web of Science

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25aYL-8 Tight-binding分子動力法によるナノ微結晶の焼結シミュレーション

鶴田健二, 東辻浩夫, 東辻千枝子

日本物理学会講演概要集 54 ( 2 ) 884 - 884 1999年9月

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