研究者詳細 - 鶴田　健二

1502 Gemini-HBCの構造と光応答に関する第一原理シミュレーション(OS15.固体物理/流体物理のマルチフィジックス/マルチスケール解析(1),OS・一般セッション講演)

清水竜樹, 鶴田健二, 深野秀樹

計算力学講演会講演論文集 2011 ( 24 ) 471 - 473 2011年10月

記述言語：日本語出版者・発行元：一般社団法人日本機械学会

A graphite nanotube is composed of Gemini type hexabenzocoronene (Gemini-HBC) as the hole-transport layer and the fullerene as the electron-transport layer. We study the doping effect on the electronic properties of Gemini-HBC to make the absorption peak broader, expecting to cover an unharvested energy resource. Here we assume that structure of doped Gemini-HBC is well represented by substituting dopant atom to one of carbon sites. Calculations of the energy and absorption spectrum are performed by the ab-initio computational method. As a result, the absorption peak of the Gemini-HBC is about 0.5μm, whereas the first and second peaks for doped Gemini-HBC are also approximately 0.5μm. In addition, the absorption spectrum of F-doped Gemini-HBC has an additional peak around 0.95μm, implying the sunlight with the longer wavelength may be absorbed.

1508 第一原理計算及びハイブリッド法によるLiイオン二次電池負極炭素材料中の拡散挙動解析(OS15.固体物理/流体物理のマルチフィジックス/マルチスケール解析(2),OS・一般セッション講演)

稲垣陽介, 鶴田健二

計算力学講演会講演論文集 2011 ( 24 ) 485 - 486 2011年10月

記述言語：日本語出版者・発行元：一般社団法人日本機械学会

Lithium ion battery (LiB) is widely used in portable electronic devices, such as cellular phones and laptop computers. Recently, needs for higher efficiency of the battery has been increasing rapidly due to the demand for electric and hybrid electric vehicle. At present, anode of LiB is mainly made of graphite. Recently, graphene has been attracting more attention as an alternative anode material. The effect of impurity doping to graphene has also been investigated recently. To optimize the materials combination for the anode applications microscopic mechanisms of such enhancement of electric capacity in LiB have to be identified. Using an ab-initio computational method, based on the density-functional theory, and its hybridized method with the classical molecular dynamics, we investigate dynamical behavior, such as diffusion processes, of Li atom in the carbon based materials with pristine, defected, and doped graphene.

1503 Si結晶中の原子空孔相互作用に関する大規模分子動力学解析(OS15.固体物理/流体物理のマルチフィジックス/マルチスケール解析(1),OS・一般セッション講演)

高田和明, 鶴田健二

計算力学講演会講演論文集 2011 ( 24 ) 474 - 475 2011年10月

記述言語：日本語出版者・発行元：一般社団法人日本機械学会

Vacancy interaction in Si crystal is studied by molecular-dynamics simulations. Using tight-binding molecular dynamics and classical molecular dynamics methods, we calculate an effective interaction potential of Si vacancy pair in bulk and in a thin slab at several temperatures. In the case of vacancy pair in bulk crystal, results reveal that there is an effective "capture radius" of the vacancies at around 8 Åat 300K and 13 Å at 600K and 1000K. Stable structure and electronic states around the vacancies in Si slab near the surface are qualitatively different from their bulk properties, reflecting a proximity surface electronic state. Results of diffusion behavior and interaction potential of the vacancy pair in the slab at finite temperatures are also reported.

22aGQ-10 Si結晶中の表面・界面付近の原子空孔間相互作用に関する分子動力学解析(22aGQ 格子欠陥・ナノ構造(シリコン系材料),領域10(誘電体,格子欠陥,X線・粒子線,フォノン))

高田和明, 鶴田健二, 小川貴史, 家富洋

日本物理学会講演概要集 66 ( 2 ) 981 - 981 2011年8月

27pTJ-10 DFT計算によるシリコン単原子空孔のスピン軌道相互作用の検討(27pTJ 格子欠陥・ナノ構造(半導体),領域10(誘電体,格子欠陥,X線・粒子線,フォノン))

小川貴史, 鶴田健二, 家富洋, 根本祐一, 金田寛, 後藤輝孝

日本物理学会講演概要集 66 ( 1 ) 979 - 979 2011年3月

フォノニック結晶による超音波の音響レンズ効果とエネルギー輸送効率

菅野祐輔, 笠井祐樹, 鶴田健二, 藤森和博, 深野秀樹, 野木茂次

日本機械学会計算力学講演会論文集(CD-ROM) 24th 2011年

半導体結晶表面における弾性波伝搬の大規模分子動力学シミュレーション

藥師川裕貴, 鶴田健二, 藤森和博

日本機械学会計算力学講演会論文集(CD-ROM) 24th 2011年

26aWZ-12 DFT計算によるシリコン単原子空孔の局在電子軌道の解析(26aWZ 格子欠陥・ナノ構造(半導体),領域10(誘電体格子欠陥,X線・粒子線フォノン))

小川貴史, 鶴田健二, 家富洋, 根本祐一, 金田寛, 後藤輝孝

日本物理学会講演概要集 65 ( 2 ) 928 - 928 2010年8月

20aHT-10 酸化物セラミックスの転位偏析に関するマルチスケール解析(20aHT 領域10 領域10,領域9合同(表面,界面,電子状態),領域10(誘電体,格子欠陥,X線・粒子線,フォノン))

鶴田健二, 小山敏幸, 尾形修司, 兵頭志明

日本物理学会講演概要集 65 ( 1 ) 971 - 971 2010年3月

Parallel FDTD simulations on optical and acoustic metamaterials

Kenji Tsuruta, Shinji Nagai, Ryosuke Umeda, Tomoyuki Kurose, Noriaki Maetani

Materials Research Society Symposium Proceedings 1223 1223-EE06 2010年

Ab Initio Simulation for Structure and Optical Response of Gemini-HBC

Tatsuki Shimizu, Kenji Tsuruta

447 - 450 2010年

108 ハイブリッド量子/古典分子動力学法によるアルミナ転位運動と添加元素効果解析(OS1.固体物理/流体物理のマルチフィジックス/マルチスケール解析(3),オーガナイズドセッション)

鶴田健二, 林明宏, 小山敏幸, 尾形修司, 兵頭志明

計算力学講演会講演論文集 2009 ( 22 ) 390 - 391 2009年10月

記述言語：日本語出版者・発行元：一般社団法人日本機械学会

We perform molecular-dynamics simulations to investigate the atomic and electronic structures of a basal edge dislocation in α-Al_2O_3. Inter-core interactions between a dissociated partial pair are evaluated by a million-atom classical molecular dynamics. The interactions consists of a short-ranged repulsion due to the elastic interaction between two singular points and a long-ranged attraction due to the stacking-fault formed between the two partials. The atomic rearrangements in the full and in the partial dislocation cores are analyzed by a hybrid quantum/classical molecular dynamics method. The local electronic structure in the dislocation core is evaluated by the density-functional method applied for a quantum-cluster region in the hybrid simulation. Effects of a doped Si atom segregated to the dislocation core are also analyzed.

1701 電磁メタマテリアルによる光閉じ込め構造のFDTDシミュレーション(OS17.フォトニック・フォノニック構造の設計とシミュレーション(1),オーガナイズドセッション)

長井慎二, 鶴田健二, 東辻千枝子

計算力学講演会講演論文集 2009 ( 22 ) 452 - 453 2009年10月

記述言語：日本語出版者・発行元：一般社団法人日本機械学会

Using the two dimensional Finite Difference Time Domain method, we demonstrate a light-confinement phenomenon by a structure composed of a negative-refractive-indexed (NRI) material. The structure, consisting of triangular lattice of mediums with a NRI and a normal material, is designed to confine an incident light by peculiar refractions at the materials boundaries. To model realistically the NRI material, we introduce the Drude-Lorentz model for the dielectric response at optical frequencies. The effects of dielectric loss in the NRI medium on the confinement efficiency of the proposed structure is reported.

1706 2次元フォノニック結晶の音波伝搬シミュレーション : 負の屈折とレンズ効果(OS17.フォトニック・フォノニック構造の設計とシミュレーション(2),オーガナイズドセッション)

前谷憲昭, 鶴田健二, 東辻千枝子

計算力学講演会講演論文集 2009 ( 22 ) 462 - 463 2009年10月

記述言語：日本語出版者・発行元：一般社団法人日本機械学会

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 acoustic waves refocused 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 reflects incident acoustic waves from the source. We show how the focal intensity is improved by using the 2D phononic crystal shield.