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排序方式: 共有19条查询结果,搜索用时 15 毫秒
1.
周世琦  郭祀远 《化学学报》1999,57(5):437-445
以反胶束系统稳定性的热力学分析为基础,综合分析了反胶束系统的三大效应,即低界面张力效应、界面弯矩效应、混合熵效应,提出了一个分子热力学模型,模型所预言的反胶束水分含量随无机盐种类、浓度、表面活性剂浓度以及助表面活性剂含量的变化与所获实验规律定量相符,还能预言反胶束内表面处电势值、表面活性剂解离度。  相似文献   
2.
提出了一个用于计算平均力势的普适性的理论框架,方法克服了以前的方法的缺陷,仅仅需要溶剂粒子在单个溶质粒子附近的密度分布作为输入.计算了两个大尺寸溶质粒子浸在小尺寸硬球溶剂浴中的平均力势,理论预言与可能的模拟数据符合.调查了溶剂-溶质相互作用势、溶剂密度、溶质粒子尺寸对过量平均力势的影响.结论是:溶剂粒子在单个溶质粒子附近的减少导致吸引的过量平均力势,而溶剂粒子在单个溶质粒子附近的聚集导致排斥的过量平均力势,高溶剂密度与大溶质粒子尺寸能强化这种趋势.讨论了这种空耗吸引-聚集排斥与生物学中的疏水吸引-水化排斥的联系.  相似文献   
3.
周世琦 《中国物理快报》2002,19(9):1322-1325
In this Letter,we truncate the functional expansion of the non-uniform first-order direct correlation function (DCF) around the bulk density at the lowest order.But the truncation is performed formally and exactly by making use of functional counterpart of the Lagrangian theorem of differential calculus.Consequently the expansion coefficient,i.e.the uniform second-order DCF,is replaced by its non-uniform counterpart whose density argument is an appropriate mixture of calculated density distribution and the bulk density with a mixing parameter determined by a hard-wall sum rule.The non-uniform second-order DCF is then approximated by the uniform second-order DCF with an appropriate weighted density as its density argument.The present formally exact truncated functional expansion predicts the density distribution in good agreement with simulation data for hard sphere and Lennard-Jones fluid exerted by an external field.  相似文献   
4.
周世琦  张晓琪 《中国物理》2002,11(10):1051-1059
The universality principle of the free energy density functional and the ‘test particle' trick by Percus are combined to construct the approximate free energy density functional or its functional derivative. Information about the bulk fluid radial distribution function is integrated into the density functional approximation directly for the first time in the present methodology. The physical foundation of the present methodology also applies to the quantum density functional theory.  相似文献   
5.
周世琦 《中国物理 B》2008,17(10):3812-3821
In this work, a bridge density functional approximation (BDFA) (J. Chem. Phys. 112, 8079 (2000)) for a nonuniform hard-sphere fluid is extended to a non-uniform hard-core repulsive Yukawa (HCRY) fluid. It is found that the choice of a bulk bridge functional approximation is crucial for both a uniform HCRY fluid and a non-uniform HCRY fluid. A new bridge functional approximation is proposed, which can accurately predict the radial distribution function of the bulk HCRY fluid. With the new bridge functional approximation and its associated bulk second order direct correlation function as input, the BDFA can be used to well calculate the density profile of the HCRY fluid subjected to the influence of varying external fields, and the theoretical predictions are in good agreement with the corresponding simulation data. The calculated results indicate that the present BDFA captures quantitatively the phenomena such as the coexistence of solid-like high density phase and low density gas phase, and the adsorption properties of the HCRY fluid, which qualitatively differ from those of the fluids combining both hard-core repulsion and an attractive tail.  相似文献   
6.
用摄动法与线性化近似耦合迭代法求解非线性的Poisson-Boltzmann方程,获得了反胶束内表面电荷密度/表面电势的两个近似解析式,具有适用于混合,非对称电解质溶液的普遍情形的特点,与计算机精确的数值解进行对比表明,在通常反胶束内部双电层表面电势的情形下,两个近似解析式分别具有1.0%与5.0%的相对误差,从而构成了非线性PBE在全区间上的部分近似解析解。  相似文献   
7.
8.
用硬球模中性胶体粒子 ,数值求解双组分Ornstein Zernike积分方程 (当大的中性胶体粒子的浓度为零时 ) ,用来决定悬浮在溶剂 (用小的硬球模拟 )中两个胶粒之间的空耗势 .所预言的空耗势与文献的模拟数据和实验数据能很好地符合 .研究发现 ,基于空耗势的有效一组分Hansen Verlet一相相变标准完全不能预言双组分系统的液 固相变 .讨论了导致这种现象的原因 :Hansen Verlet一相相变标准不能自地处理有效一组分系统中固相与液相的体积能  相似文献   
9.
周世琦 《中国物理快报》2003,20(12):2107-2109
Based on the functional integral procedure, a recently proposed bridge density function [J. Chem. Phys. 112 (2000) 8079] is developed to calculate global thermodynamic properties of non-uniform fluids. The resulting surface tension of a hard wall-hard sphere interface as a function of the bulk hard sphere fluid density is in good agreement with the available simulation data. The proposed numerical procedure from the approximation of non-uniform first-order direct correlation function to a non-uniform system with excess Helmholtz free energy is of fundamental importance for phase behaviour under the confined condition due to the fact that many available simple approximations in classical density functional theory are for non-uniform first-order direct correlation function.  相似文献   
10.
反胶束萃取蛋白质中静电相互作用能的研究   总被引:6,自引:0,他引:6  
在双球坐标系中,求解了描述蛋白质位于反胶束水池中偏心位置时所形成扩散双电层的非线性Poisson-Boltzmann方程,同时也求解了蛋白质与反胶束单独存在时,以及蛋白质位于反胶束水池中心位置时所形成扩散双电层的上述方程。求解时,在反胶束内表面处使用了非线性的电荷调节边界条件,基于上述数值解,应有和自由能方法,计算了蛋白南被萃取进入反胶束水池过程中的静电相互作用能量,在此基础上,就反胶束水池中的耦  相似文献   
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