@techreport{oai:jaxa.repo.nii.ac.jp:00041863,
 author = {森本, 久雄 and 亀井, 信一 and 正木, 匡彦 and 伊丹, 俊夫 and Morimoto, Hisao and Kamei, Shinichi and Masaki, Tadahiko and Itami, Toshio},
 month = {Mar},
 note = {液体内の物質移動の機構を明らかにするため単純液体金属の分子動力学シミュレーションを行った。分子動力学シミュレーションでは、剛体球流体の自己拡散に対するSpeedyの式の有効性を検討した。剛体球流体の数値模型として無次元形の方程式を記述した。充填率、拡散係数、Enskogの式およびSpeedyの式を定義し、拡散係数とEnskogの式に基づき後方散乱係数を計算した。剛球体系は充填率に依存して液体または固体としての性質を示す。液体と固体間の遷移状態は充填率だけではなく初期条件にも左右されることが分かった。Boublik-Nozbeda方程式に基づいて遷移状態を論じ、また、本分子動力学シミュレーションの有効性を明らかにした。剛球体系の液体構造を動径分布関数の形で評価した。本剛球体系の構造は液状であるように見られ、液相に特有の振動が存在する。無次元拡散係数と後方散乱係数の充填率への依存度を計算した。拡散係数は充填率が0.05〜0.45の範囲でSpeedyの式と一致した。, The molecular dynamics simulation of simple liquid metals was carried out in order to clarify the mechanism of mass transfer in liquids. In the molecular dynamics simulation, the validity of Speedy et al's formula for self-diffusion of hard sphere fluids was studied. Equations in non-dimensional forms were written for numerical modeling of hard sphere fluid. Packing fraction, diffusion coefficient, Enskog's formula and Speedy's formula were defined respectively. The back scattering factor was calculated based on the diffusion coefficient and Enskog's formula. The hard sphere system behaves as a liquid or a solid depending on the packing fraction. Transition state between liquid and solid is found not to depend on only the packing fraction but also on the initial conditions. The transition state was discussed based on Boublik-Nozbeda equation, and the validity of the present molecular dynamic simulation was shown. The liquid structure of the hard sphere system was evaluated in the form of radial distribution function. The structure of present hard sphere system seems to be liquid like and there exists a specific oscillation in liquid phase. The dependence of the non-dimensional diffusion coefficient and the back scattering factor on packing fraction was calculated. The diffusion coefficient agreed with the Speedy's formula over the packing fraction range 0.05 to 0.45., 資料番号: AA0029039004, レポート番号: NASDA-TMR-000013E},
 title = {Molecular dynamics simulations of atomic transport of hard sphere fluids: A verification of Speedy's equation for the self-diffusion of hard sphere fluids},
 year = {2001}
}