The present work uses the concept of a scaled particle along with the perturbation and variation approach, to develop an equation of state （EOS） for a mixture of hard sphere （HS）, Lennar-Jones （L J） fluids. A su...The present work uses the concept of a scaled particle along with the perturbation and variation approach, to develop an equation of state （EOS） for a mixture of hard sphere （HS）, Lennar-Jones （L J） fluids. A suitable flexible functional form for the radial distribution function G（R） is assumed for the mixture, with R as a variable. The function G（R） has an arbitrary parameter m and a different equation of state can be obtained with a suitable choice of m. For m = 0.75 and m = 0.83 results are close to molecular dynamics （MD） result for pure HS and LJ fluid respectively.展开更多
We present a simple method of obtaining various equations of state for hard sphere fluid in a simple unifying way. We will guess equations of state by using suitable axiomatic functional forms （n = 1, 2, 3, 4, 5） fo...We present a simple method of obtaining various equations of state for hard sphere fluid in a simple unifying way. We will guess equations of state by using suitable axiomatic functional forms （n = 1, 2, 3, 4, 5） for surface tension Sn （r）, r≥ d/2 with intermolecular separation r as a variable, where m is an arbitrary real number （pole）. Among the equations of state obtained in this way are Percus-Yevick, scaled particle theory and Carnahan-Starling equations of state. In addition, we have found a simple equation of state for the hard sphere fluid in the region that represents the simulation data accurately. It is found that for both hard sphere fluids as well as Lennard-Jones fluids, with m = 3/4 the derived equation of state （EOS） gives results which are in good agreement with computer simulation results. Furthermore, this equation of state gives the Percus-Yevick （pressure） EOS for the m = 0, the Carnahan-Starling EOS for rn = 4/5, while for the value of m = 1 it corresponds to a scaled particle theory EOS.展开更多
This work is a simulation model with the LAMMPS calculation code of an electrode based on alkali metal oxides (lithium, sodium and potassium) using the Lennard Jones potential. For a multiplicity of 8*8*8, we studied ...This work is a simulation model with the LAMMPS calculation code of an electrode based on alkali metal oxides (lithium, sodium and potassium) using the Lennard Jones potential. For a multiplicity of 8*8*8, we studied a gap-free model using molecular dynamics. Physical quantities such as volume and pressure of the Na-O and Li-O systems exhibit similar behaviors around the thermodynamic ensembles NPT and NVE. However, for the Na2O system, at a minimum temperature value, we observe a range of total energy values;in contrast, for the Li2O system, a minimum energy corresponds to a range of temperatures. Finally, for physicochemical properties, we studied the diffusion coefficient and activation energy of lithium and potassium oxides around their melting temperatures. The order of magnitude of the diffusion coefficients is given by the relation Dli-O >DNa-O for the multiplicity 8*8*8, while for the activation energy, the order is well reversed EaNa-O > EaLi-O.展开更多
研究水分子进入碳纳米管(CNT)时的物理特性.采用连续模型连同Lennard-Jones势函数,得到单壁面碳纳米管(SWCNT)与单个水分子之间的van der Waals力.水分子选择3种方位进入纳米管,其中水分子质心位于纳米管轴线上.对不同的纳米管半径和水...研究水分子进入碳纳米管(CNT)时的物理特性.采用连续模型连同Lennard-Jones势函数,得到单壁面碳纳米管(SWCNT)与单个水分子之间的van der Waals力.水分子选择3种方位进入纳米管,其中水分子质心位于纳米管轴线上.对不同的纳米管半径和水分子进入方位,广泛地研究了相互作用力、能量和速度的分布.用分子动力学(MD)模拟得到的结果,来验证上述得到的相互作用力和能量分布.导出水分子进入纳米管时的可吸入半径,并详细地给出了有利于水分子进入纳米管半径的界限.计算单个水分子进入纳米管的速度,为不同进入方位的水分子,给出最大的入口速度和最大的管内速度.展开更多
two equations for the calculation of surface tension of pure liquids are derived based on statistical thermodyanics by expressing the intermolecular potential as lennard-Jones pair potential.This method is simple,accu...two equations for the calculation of surface tension of pure liquids are derived based on statistical thermodyanics by expressing the intermolecular potential as lennard-Jones pair potential.This method is simple,accurate and easy to use.The calculation results for the 22 pure liquids show that these equations are superior to the empirical forula and other theoretical equations.The average relative deviations for these two equations are within 5% and 1.5% respectively.展开更多
文摘The present work uses the concept of a scaled particle along with the perturbation and variation approach, to develop an equation of state （EOS） for a mixture of hard sphere （HS）, Lennar-Jones （L J） fluids. A suitable flexible functional form for the radial distribution function G（R） is assumed for the mixture, with R as a variable. The function G（R） has an arbitrary parameter m and a different equation of state can be obtained with a suitable choice of m. For m = 0.75 and m = 0.83 results are close to molecular dynamics （MD） result for pure HS and LJ fluid respectively.
文摘We present a simple method of obtaining various equations of state for hard sphere fluid in a simple unifying way. We will guess equations of state by using suitable axiomatic functional forms （n = 1, 2, 3, 4, 5） for surface tension Sn （r）, r≥ d/2 with intermolecular separation r as a variable, where m is an arbitrary real number （pole）. Among the equations of state obtained in this way are Percus-Yevick, scaled particle theory and Carnahan-Starling equations of state. In addition, we have found a simple equation of state for the hard sphere fluid in the region that represents the simulation data accurately. It is found that for both hard sphere fluids as well as Lennard-Jones fluids, with m = 3/4 the derived equation of state （EOS） gives results which are in good agreement with computer simulation results. Furthermore, this equation of state gives the Percus-Yevick （pressure） EOS for the m = 0, the Carnahan-Starling EOS for rn = 4/5, while for the value of m = 1 it corresponds to a scaled particle theory EOS.
文摘This work is a simulation model with the LAMMPS calculation code of an electrode based on alkali metal oxides (lithium, sodium and potassium) using the Lennard Jones potential. For a multiplicity of 8*8*8, we studied a gap-free model using molecular dynamics. Physical quantities such as volume and pressure of the Na-O and Li-O systems exhibit similar behaviors around the thermodynamic ensembles NPT and NVE. However, for the Na2O system, at a minimum temperature value, we observe a range of total energy values;in contrast, for the Li2O system, a minimum energy corresponds to a range of temperatures. Finally, for physicochemical properties, we studied the diffusion coefficient and activation energy of lithium and potassium oxides around their melting temperatures. The order of magnitude of the diffusion coefficients is given by the relation Dli-O >DNa-O for the multiplicity 8*8*8, while for the activation energy, the order is well reversed EaNa-O > EaLi-O.
文摘研究水分子进入碳纳米管(CNT)时的物理特性.采用连续模型连同Lennard-Jones势函数,得到单壁面碳纳米管(SWCNT)与单个水分子之间的van der Waals力.水分子选择3种方位进入纳米管,其中水分子质心位于纳米管轴线上.对不同的纳米管半径和水分子进入方位,广泛地研究了相互作用力、能量和速度的分布.用分子动力学(MD)模拟得到的结果,来验证上述得到的相互作用力和能量分布.导出水分子进入纳米管时的可吸入半径,并详细地给出了有利于水分子进入纳米管半径的界限.计算单个水分子进入纳米管的速度,为不同进入方位的水分子,给出最大的入口速度和最大的管内速度.
文摘two equations for the calculation of surface tension of pure liquids are derived based on statistical thermodyanics by expressing the intermolecular potential as lennard-Jones pair potential.This method is simple,accurate and easy to use.The calculation results for the 22 pure liquids show that these equations are superior to the empirical forula and other theoretical equations.The average relative deviations for these two equations are within 5% and 1.5% respectively.
