排序方式: 共有59条查询结果,搜索用时 15 毫秒
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液体的表面张力与内压 总被引:1,自引:0,他引:1
在利用Onsager模型推导液体表面张力与内压间的关系时,文献[4]忽视了曲率对表面张力的影响,致使计算值与实验值的偏差较大。本文对此作了修正,建立了一个新的关系式,用实验数据检验表明,它能满意地适用于广阔温度范围内的各种液体。 相似文献
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研究了silicalite-1分子筛的不同后处理方法对其催化环己酮肟Beckmann重排制己内酰胺性能的影响,这些方法包括水(或氨)蒸气处理以及在碱性、酸性或中性条件下用NH4NO3处理. 结合XRD,FT-IR和 29Si MAS NMR表征结果对silicalite-1催化剂的活性中心进行了探讨. 结果表明,碱性条件下用NH4NO3进行后处理对提高分子筛的催化性能最为有利. 分子筛上无规则排布的末端硅羟基数量的减少,以及具有相互氢键作用的邻式硅羟基的产生是其催化性能提升的主要原因. 相似文献
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应用Yethiraj的加权密度近似泛函理论研究平板狭缝中方阱链流体的密度分布,系统的Helm holtz自由能泛函分为理想气体的贡献利剩余贡献两部分,其中剩余贡献部分分别采用刘洪 来等人建立的基于空穴相关函数的方阱链流体状态方程和Gil-Villegas等人提出的统计缔合 流体理论状态方程(SAFT-VR)结合简单加权密度近似计算.考察了不同链长、温度、系统密度 和壁面吸引强度下平板狭缝中方阱链流体的密度分布,并与Monte Carlo(MC)模拟结果进行 了比较.结果表明采用不同的状态方程对密度分布的计算有明显的影响,对于受限于硬壁狭 缝中的方阱链流体,温度和密度比较高时,两种状态方程计算的结果均与MC模拟符合得比较 好,在低温和低密度下效果变差,SAFT-VR方程的计算结果更接近于MC模拟结果.对于受限于 方阱壁狭缝中的方阱链流体,由于系统密度分布的非均匀性加强,采用两种状态方程计算的 结果均与MC模拟结果有一定偏差,寻找更合适的权重函数是进一步改进的关键.
关键词:
密度泛函理论
非均匀流体
密度分布
固液界面
方阱链 相似文献
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The adsorption of asymmetrical triblock copolymers from a non-selective solvent on solid surface has been studied by using Scheutjens-Fleer mean-field theory and Monte Carlo simulation method on lattice model. The main aim of this paper is to provide detailed computer simulation data, taking A8-kB20Ak as a key example, to study the influence of the structure of copolymer on adsorption behavior and make a comparison between MC and SF results. The simulated results show that the size distribution of various configurations and density-profile are dependent on molecular structure and adsorption energy. The molecular structure will lead to diversity of adsorption behavior. This discrepancy between different structures would be enlarged for the surface coverage and adsorption amount with increasing of the adsorption energy. The surface coverage and the adsorption amount as well as the bound fraction will become larger as symmetry of the molecular structure becomes gradually worse. The adsorption layer becomes thicker with increasing of symmetry of the molecule when adsorption energy is smaller but it becomes thinner when adsorption energy is higher. It is shown that SF theory can reproduce the adsorption behavior of asymmetrical triblock copolymers. However, systematic discrepancy between the theory and simulation still exists.The approximations inherited in the mean-filed theory such as random mixing and the allowance of direct back folding may be responsible for those deviations. 相似文献
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硫醇和硫醚的沸点与分子结构之间关系的拓扑化学研究 总被引:29,自引:1,他引:29
根据分子拓扑学原理, 用染色因子标识原子性质的差异, 发展了一种适用于含原子分子体系结构性能关系研究的新方法。据此探讨了硫醇和硫醚的沸点与分子结构之间的关系, 提出一个既能合理表征结构性能关系, 又能预测沸点的定量关系式。 相似文献