理想气体任意过程最高和最低温度的计算方法

给出理想气体任意过程最高和最低温度的三种计算方法，用p-V图中的直线过程、圆过程、椭圆过程为例，计算该过程最高、最低温度的状态。     

Isoentropic and Isoenthalpic Temperatures of Protein Unfolding in Hydrophobic Interaction Chromatography

Hydrophobic interaction chromatography (HIC) is widely used for the separation and purification of biopolymers in their native state, and now also becomes a new method to refold the denatured proteins1. The effect of salt or water concentration2 on the pr…     

Thermochemical and thermal analysis on N-(p-methylphenyl)-N'-(2-pyridyl)urea

Low temperature heat capacities of N-(p-methylphenyl)-N'-(2-pyridyl)urea were determined by adiabatic calorimetry method in the temperature range from 80 to 370 K. It was found that there was not any heat anomaly in this temperature region. Based on the experimental data, some thermodynamic function results were obtained. Thermal stability and decomposition characteristics analysis of N-(p-methylphenyl)-N'-(2-pyridyl)urea were carried out by DSC and TG. The results indicated that N-(p-methylphenyl)-N'-(2-pyridyl)urea started to melt at ca. 426 K (153°C) and the melting peak located at 447.01 K (173.86°C). The melting enthalpy was 204.445 kJ mol^-1 (899.6 J g^-1). The decomposition peak of N-(p-methylphenyl)-N'-(2-pyridyl)urea was found at 499.26 K (226.11°C) from DSC curve. This result was similar with that from TG and DTG experiment, in which the mass loss peak was determined as 500.4 K (227.2°C). This revised version was published online in August 2006 with corrections to the Cover Date.     

Critical thermodynamic analysis of differential scanning calorimetry for studying chemical kinetics

A critical thermodynamic analysis of differential thermal calorimetry is reported herein to gain further insight into the phenomena leading to the reported differences between kinetic parameters extracted from isothermal DSC methods and those from dynamic DSC methods. The sources have been identified for the variations observed in the total heat of reaction as a function of the heating rate in dynamic DSC experiments. The analysis clearly indicates that these variations are, in fact, to be anticipated. The relationships necessary for extracting kinetic data from both isothermal and dynamic experiments are derived rigorously by resorting to classical thermodynamics. This work was supported by the Cooperative State Research Service, U.S. Department of Agriculture, under Agreement No. 92-37500-7911.     

R22-DMA热力学性质及吸收压缩式热泵系统优化

1引言吸收压缩式（SC）热泵是一种适用于变温热源的高效复合式热泵系统，比常规压缩式热泵具有工作范围广，工作压力低以及较高COP值等特点。文献出对以R22－DMA为工质的SC热泵进行了实验研究。本文则对新型工质R22－DMA的热力学性质进行研究整理，给出计算二元系统的蒸汽压、烩、摘等的实用公式；并对以其为工质的一种新型SC热泵循环进行计算机模拟优化分析，给出了实际SC热泵在典型制冷工况下的制冷性能及其优化条件。2R22－DMA的热力学性质2．1汽波相平衡R22－DMA二元系统的汽液相平衡实验数据较缺乏，文献［2］给出部分温度…     

Dielectric studies in dilute solutions

Dielectric studies in dilute solutions of cyclohexane and benzene have been carried out in the temperature range 294–318°K. The observed data have been utilized to evaluate the relaxation times and thermodynamic parameters of these molecules. The high values ofα for 2-acetyl pyridine indicate the occurrence of more than one relaxation time. In the remaining systems, the observed lowα values indicate their rigid behaviour. The variation in the dielectric relaxation time is mostly correlated with the change in the heterocyclic configuration of the system.     

Unusual pressure-induced phase behavior in crystalline poly-4-methyl-pentene-1

We report some highly unusual phase behavior, of general implication for condensed matter, on the polymer poly(4-methyl-pentene-1) (P4MP1) induced by changes in pressure and temperature, as observed in situ by x-ray diffraction. Upon increasing pressure beyond a threhold, the polymer, crystalline under ambient conditions, loses its crystalline order isothermally, passing through a continuously varying sequence of mesomorphic states, the process being reversible. This behavior is observed in two widely separated temperature regions, suggesting, for the first time in a single component system, the possibility of reentrant liquid-crystal and amorphous phases. At the upper temperature region (ca. 250°C) there is a consecutive increase and decrease of melting point with pressure. In the lower temperature region (room temperature) the pressure converts the crystal into an amorphous-like glass obviating the need for going through the melt first, and this in a reversible manner. The latter pressure-induced disordered phase converts into crystal on raising the temperature, and reverts to the glassy, disordered phase on lowering the temperature. Some aspects of this behavior have been found quite recently in water-ice and silica but the process of “melting on cooling” has no precedent in any known system. Other unexpected findings include a new pressure-induced modification of P4MP1 with a one-way only entry with temperature, but full reversibility with pressure leading to a triple point in the PT phase diagram. The above highly uncommon results are putting several prevailing preconceptions to test which are being scrutinized. In the course of it some early expectations on general phase behavior, allowing among others for reentrant phases in one component systems, are being invoked as potentially appropriate for certain polymeric systems, if not for condensed matter in general. © 1993 John Wiley & Sons, Inc.     

用于预测疏松材料冲击压缩特性的热力学模型

 在一定的假设条件下，从基本的热力学关系出发，导出了一个新的物态方程表达式。利用这一新形式特态方程所建立的热力学模型，可预测疏松材料的冲击压缩行为。以低、中、高冲击阻抗的铝、铜和钨为示例，将本模型的理论计算曲线与实验冲击压缩数据比较，表明本模型的在宽广的压力范围内具有良好的普活性；对不同初妈密度，疏松材料的冲击压缩行为均显示出较为满意的理论经历测能力；与现有的其它疏松材料物态方程模型相比，本模型在理论上和实际应用中均具有较大的优越性。     

The possibilities of the atomic absorption method of determining the elements in a methyl acetylene-nitric oxide (I) flame

Using the method of thermodynamic simulation, we determine the adiabatic temperature and the efficiency of atomization of 54 elements in a methyl acetylenenitric oxide (I) flame. We established the optimum compositions of the flame for determining each element and carried out a comparison with the analytical characteristics of an acetylene-nitric oxide (I) flame. Ural State Technical University of Russia, 19, Mir Str. Ekaterinburg, 620002, Russia. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 65, No. 1 pp. 14–21. January Febraury, 1998.