对球状液滴拉普拉斯公式热力学推导方法的讨论

本文针对球状液滴拉普拉斯公式热力学推导方法进行了讨论分析。首先从界面热力学基本方程的建立方法和界面热力学基本方程中作为偏微分的压强的数学定义两个角度进行分析,得出了液滴界面热力学基本方程中,压强为与之平衡的外界气体压强。另外,从实际发生的物理过程来看,本文所质疑的球状液滴拉普拉斯公式的热力学推导方法采用无外力做功时液滴体积增大d V的过程是明显违反热力学第一定律的。     

活用dF=δW'推导热力学公式

应用dF=δW'推导了拉普拉斯方程、开尔文方程、毛细管液柱高度计算公式、杨方程、贝林方程和大气分布定律等热力学公式,给出了这类推导的一般思路。     

关于一些热力学公式使用条件的讨论

物理化学中的热力学公式在不同条件下有不同的衍变形式,极易诱导学生产生错误理解。通过实例分析,对热力学能和焓变化计算公式、赫姆霍兹自由能和吉布斯自由能判据、热力学基本方程等的使用和理解中存在的一些问题予以讨论。     

苯酚+环己酮固液平衡的热力学计算

对苯酚+环己酮低温固液平衡体系,直接由相图和基本热力学数据,计算体系热力学性质。使用Gibbs-Duhem方程和四参量GE方程,在220.00～241.00K区间,计算了8个温度的两组元活度系数和GE方程,在241.00K,x2=0.5、GE=783.69J/mol,SE=97.11/(mol.K),HE=24186.69J/mol。241.00K相合熔点化合物的离解平衡ΔrGm=1982.93J/mol,ΔrHm=5753.241J/mol,ΔrSm=15.65J/(mol.K)。体系偏离于规则溶液模型。在化合物存在相区,离解反应的反应焓变和熵变均可视之为常量。液相区不会存在稳定的化合物。     

热力学方程在计算热力学函数中的应用

热力学方程是包含热力学基本方程、热力学状态方程以及吉布斯-亥姆霍兹方程在内的广泛的一组方程。文中对目前物理化学教材中很少提及的其他热力学状态方程进行了系统的总结和推导,同时强调理论的系统性和完整性在教学中的重要性,并在此基础上导出了物理化学教材中很少见到的吉布斯-亥姆霍兹第一方程及其在表面化学中的应用。在物理化学教学中需要特别强调特征变量的重要性,以及特征变量和化学反应条件之间的内在关系,并注意与交叉学科物理专业的热力学和统计物理学的衔接。     

化学方程式中“△”的热动力学含义

在中学化学教科书中。常常碰到如下化学反应方程式：Aa+Bb=mM+nN式中加热符号是反应必须条件,随不同反应其作用和目的不同。现从热力学和动力学两方面作一简要分析。     

关于化学平衡常数有无单位的看法

由质量作用定律导出的化学平衡常数一般具有单位,而由热力学基本方程导出的化学平衡常数是无单位的。这两种对同一化学平衡规律的表示似乎是迥然不同的,但是从下面的推导说明中不难看出两者实质上是统一的。     

理想气体绝热过程方程的4种推导*

物理化学的一个重要魅力是公式的交互关联性。以理想气体绝热过程方程为例,详细地叙述了如何从热力学第一定律、熵差计算公式、偏微分和全微分等4个不同的起点出发,利用必要的热力学关系,最后到达相同的终点的推演过程。     

内波在具有水平流的非均匀海洋中的传播

本文研究了在水平及垂向分层的海洋中基本水平流对内波传播的影响。由准静态近似假设导得具有水平流的非均匀海洋中内波传播基本方程式,采用几何光学近似得到程函方程及传输方程.在M=M(y)i+M(x)j的一类流场中得到推广的Snell定律及波射线的解析式。     

勒夏特列原理与合成氨的平衡移动

勒夏特列原理是处理条件变化时化学平衡移动方向问题的重要依据。本文从勒夏特列原理的定性特点出发,针对合成氨体系中“奇怪的平衡移动”问题,采用热力学基本方程和简明的数学分析方法,给以回答和讨论。此外,简要介绍勒夏特列的生平。     

Eu3+对DMPC人工膜脂双层主相变温度的影响

利用付里叶变温红外光谱和核磁共振谱研究了Ｅｕ３＋离子与人膜ＤＭＰＣ脂双层配位作用的影响，实验发现Ｅｕ３＋离子对ＤＭＰＣ脂双层影响不局限于界面区域，而且扩展到整个酰基链，因而使ＤＭＰＣ脂双层的主相变温度提高了６℃。     

土遗址保护材料综述

基于对土遗址保护材料选择的基本原则和现今国内外土遗址保护材料的研究将其分为无机材料、有机材料和有机/无机杂化材料三大类并对一些常用的土遗址保护材料及其加固保护机理进行了介绍。     

Excess functions of mixing along the liquidus and the effect of aprotic solvents upon the solubility of solid non-electrolytes

A method of evaluating excess enthalpy and excess entropy along the liquidus of a eutectic system from vapor pressure and solubility data has been presented. The solutions of the four non-electrolytes of increasing polarity (octadecane, 2,6-di-tert-butyl-4-methylphenol, 3-methyl-6-nitrophenol and benzoic acid) in aprotic solvents have been studied. The solvent effect upon excess funtions and solubility curves is discussed. The considerable contribution of short-term orientational order in liquids is emphasized.Communicated at the Festsymposium celebrating Dr. Henry V. Kehiaian's 60^th birthday, Clermont-Ferrand, France, 17–18 May 1990.     

原子量测定发展史与原子量基准的国际化历程

从古代思辨的原子论到近代科学的原子-分子论,原子量的测定是其从定性到定量发展的关键。原子量为化学家们研究物质提供了新的思路。原子量内涵的相对性,决定了原子量基准的重要性。原子量最终取代了测定与传播都早于它的当量,并走向了国际化,这个过程不仅可让我们认识到科学发展的曲折艰辛,也让人们理解了科学交流的重要性。     

Correlation Analysis of the Runoff of the Rivers and the Seisms in China

In recent hundred years the annual discharge variations of the Changjiang River (represented by the Yichang station) and the Huanghe River (represented by Shanxian and Tangnaihe, respectively) have closely related to the geographical distribution of the earthquakes coming about in China in the same year, Both the occurrence of the destructive seism or seismic swarm in the river basins and the disappearance of the shocks in the east and south of the basins are the conditions that the Changjiang and Huanghe Rivers are the high flow while that the strong earthquake of magnitude 7 or more occurred in North China is the condition for the Changjiang low flow year and that of 6 or more in the Qilian Mountains area is for the Huanghe River. In the latter part of this paper, a 2-year sample is given to explain that the conditions of the 2 rivers being high flow years are that the north-south seismic belt is active and in the meanwhile no seism occurred in South China, and those of the low flow year are that the     

Effects of Salts of Varying Nature on the Energy Stability of the Structure of Aqueous Solutions

For cyclopentane used as a model hydrocarbon, solubility in water and aqueous solutions of various salts (chlorides, bromides, iodides, rhodanides, alkali metal acetates and sulfates, and calcium and zinc chlorides) at 20±1°C has been determined. Variations of the increment of the methylene group ( ) induced by salt additions to water, are calculated. When the salt is added to the solution, the increment increases drastically irrespective of the nature of the ions, thus stabilizing the structure of the solution. The increase, however, depends significantly on the nature of the salt, which is explained by different degrees of structuring of the aqueous solution caused by the ions of the salts.     

A simple extension of the external magnasco-perico localization procedure to the virtual MO-Space

The external localization procedure of Magnasco and Perico is extended to the unoccupied molecular orbitals of the Fock-operator. The formal correspondence between bonding orbitals and localized antibonding MOs is demonstrated. Localized occupied and virtual one-electron functions are calculated within a semiempirical INDO-Hamiltonian and are analyzed; the externally localized occupied MOs are compared with energy localized orbitals computed by the Edmiston and Ruedenberg procedure. Various applications of the fully localized (occupied and virtual) MO set are discussed.     

槲皮素及其异构体分子的结构性质研究

槲皮素是一类有着重要药理活性的黄酮类化合物。本文在B3LYP/6-31G**水平上对槲皮素及其14种异构体进行了几何优化,得到各种异构体的结构与性质。由电荷布居数分析出B环是此类多羟基化合物的活性部分,3位-OH的存在抑制了A、C环的活性。同时,表明此类化合物中必有分子内氢键形成。并给出了最稳构型、槲皮素和标准结构三类分子的振动光谱。探讨了它们的构效关系。     

Quantum-chemical calculations of the dissociation energy of the C-H bond in hydrocarbons,alcohols, and ethers

The dissociation energy of the C-H bonds in hydrocarbons, alcohols, and ethers were calculated by semiempirical MNDO, AM1, and PM3 methods. The average error of calculations of theD(C-H) values by using various quantum-chemical methods is 1.3 kcal mol^–1.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 12, pp. 2858–2861, December, 1996.