偏钛酸密度与质量浓度之间换算常数的确定与分析

分析了温度对偏钛酸密度的影响规律，找出利用温度和密度的回归方程校准密度计(比重计)的方法，同时利用物理和化学方法，确定和验证了浆料密度与其浓度换算规律的经验常数，结果令人满意。     

浓乙醛比重,温度的对应实验值

针对浓乙醛比重随温度变化而变化的问题，利用则温度比重的方法，找出了特定终了度下和比重的对应值，给生产和使用厂家提供了参考。     

乙腈与甲基自由基反应的直接动力学研究

本文利用从头算分子轨道方法和变分过渡态理论研究了乙腈与甲基自由基反应的动力学性质,在300—2100K温度的范围内,利用传统过渡态理论和考虑到量子隧道效应的校正的变分过渡态理论计算了反应速率常数,结果表明变分作用很小,而随着温度的升高隧道效应对理论反应速率常数的计算是有一定影响的。     

离子平衡模型确定肌酸的等电点

根据水溶液中肌酸宏观微元平衡和微观离子平衡关系，推导了肌酸溶解度随温度和pH值的变化关系，并应用重量法测得了水溶液中肌酸的溶解度。通过对实验数据的拟合，得到了宏观及微观解离常数，进而得到肌酸在各温度下的等电点数据。结果表明，当体系温度越高时，相应肌酸的等电点越低，本征溶解度越大；另外将40℃下的酸性解离常数与文献值对比后发现误差仅为0．9％，结果相当可信。通过已经得到的微观解离常数和宏观解离常数，计算得到了20℃下各微观离子的浓度分率值随pH值的变化关系。从中可以发现，在等电点附近，肌酸在水溶液中主要是以两性离子形式存在，在碱性环境和酸性环境中分别主要以负离子和正离子形式存在，而对于中性分子的浓度分率在全程pH值范围内均较低。     

Cl+CH3CN→CH2CN+HCl的动力学研究

采用Gaussian 98从头算程序包，从理论上对乙腈与氯原子的夺氢反应的动力学进行了研究。在UB3LYP／6—311G（d，p）水平下优化了反应物、产物和过渡态的几何结构，用UMP4（SITFQ）方法进行了单点能校正，并计算出它们的谐振频率和反应在温度区问250～750K的速率常数。     

利用废气余热的热水装置

我国机立窑燃烧热效率一般在45％左右。余热利用资源潜力很大且方式众多，如余热锅炉、发电、烘干等。我厂Φ2.2×8.5m塔式机立窑利用余热制作了一台热水装置。加热器受来自窑面废气的综合传热后，一部分水受热温度升高，比重降低，与另一部分不受热的水比较就产生了比重差。于     

乙腈与氧原子反应的动力学研究

采用Gaussian98从头算程序包,从理论上对乙腈与氧原子反应的动力学进行了研究。在UB3LYP/6—311 G(d,p)水平下优化了反应物、产物和过渡态的几何结构,用UMP4(SDTQ)方法进行了单点能校正,并计算出它们的谐振频率和反应在温度范300-2100℃的速率常数。     

常用氨合成催化剂的反应速率常数和最佳活性使用温度

根据常用的6种氨合成催化剂的本征活性测定数据，用焦姆金动力学方程回归得到反应速率常数与温度的关系。利用所得反应速率常数，模拟了这6种氨合成催化剂在中型氮肥厂φ1000mm三套管氨合成塔的反应结果。从催化剂的使用温度来看，从A106、A109、A110－1、A110－2、ICI74－1到ZA－5最佳活性使用温度不断降低。     

钇(Ⅲ)与卟啉配位反应的物理化学性质研究

用光度法研究了5-(4-羟基苯基)-10,15,20-三苯基卟啉(H2TOHPP)在溶剂CHCl3中与Y3 离子配位反应的动力学及热力学,求得了钇(Ⅲ)卟啉生成反应的速率常数、活化能以及平衡常数和配位数,并利用温度系数法求得了反应体系的热力学函数△rHθm和△rSθm,讨论了反应过程中的电子吸收光谱.     

氯化氢工序出酸系统研究与应用

介绍了出酸系统下酸比重、吸收水阀门开度和下酸温度之间的关系,找出了出酸时吸收水切换过程中的下酸温度临界点,有利于更快更安全的将下酸比重控制在合格的范围内。     

Influence of temperature fluctuations on the thermal explosion of a single particle

A statistical approach is used to study the influence of a random field of temperature in the ambient medium on the thermal stability limits of a particle with an exothermal chemical reaction. Temperature fluctuations in the ambient medium are modeled with a spatially uniform, statistically stationary, random Gaussian process with a finite time of autocorrelation function decay. A closed equation for the particle temperature probability density is derived by the method of functional differentiation. Stochastic drift of the particle in the temperature space, which makes the particle reach the critical temperature of the thermal explosion, is studied with the use of the Kolmogorov backward equation for the transition probability density. On the basis of the numerical solution of the equation for the particle temperature probability density, the stationary distribution of this probability is demonstrated to have a bimodal structure. The influence of the time of thermal relaxation of the particle and the integral time scale of temperature fluctuations in the ambient medium on the loss of thermal stability of the particle with volume heat release is examined.     

SMA工业生产计量及分析方法

运用密度法建立了可用于苯乙烯－马来酸酐共聚物（SMA）工业生产听密度－温度－浓度关系式。应用表明，此式在工业生产计量仪表的标定中是可信和可靠的。利用工业生产获得了有关工艺参数，还建立了针对SMA生产的反应器方程式。经20d连续工业生产考察表明，用反应器方式式所预测的转化率与实际值非常吻合，该方程式具有指导SMA工业生产的意义。     

Temperature Dependence of Liquid-Vapor Nucleation Rate for the Yukawa Model Fluid

ABSTRACT

The nonclassical nucleation theory based on the density functional method for the Yukawa model fluid is studied. The integral equation that determines the density profile and the work of formation of a nucleus is transformed into a simple differential equation of the Ginzburg-Landau (or Cahn-Hilliard) model of phase transition such that it can be solved numerically. The temperature dependence of the nucleation rates of liquid drops and of vapor bubbles of this Yukawa model fluid is compared with the predictions from the classical nucleation theory. The resultant temperature dependence and deviation from the classical prediction for liquid drops is compatible with the observed discrepancies between the experimental results and the classical predictions.     

纯CO2体系扩散性质的分子动力学模拟

使用基于COMPASS力场的分子动力学（MD）模拟方法计算了CO2在气相、液相以及超临界区的自扩散系数。计算结果表明温度对扩散系数的影响在密度较低时比较明显,随着密度的升高温度的影响逐渐减弱;密度较高时密度的影响对扩散系数起主导作用。通过研究温度和密度对扩散系数的影响规律,提出了预测CO2自扩散系数的新方程,该方程与模拟值和文献试验值吻合良好。     

Thermodynamic properties of a new working pair: 1-Ethyl-3-methylimidazolium ethylsulfate and water

Vapor pressures, heat capacities and densities of the 1-ethyl-3-methylimidazolium ethyl sulfate (EMISE) + water were measured at the various temperatures and ionic liquid concentrations. The system was chosen as a novel candidate for organic working pairs for an absorption heat pump. The vapor pressures of the solution were correlated by the NRTL model, the heat capacity and density of the solution were correlated by the polynomial equation as a function of temperature and concentration, and the parameters in the regression equation were determined by a Levenberg–Marquardt method, the average relative deviations between the experimental and calculated values in vapor pressure, heat capacity and density measurements were 1.9%, 1.2%, 0.8%, respectively. The vapor pressures of the solution decreases with the decrease in solution temperature and with the increase in EMISE mole concentration, the heat capacity of the solution decreases with EMISE mole concentration at the same temperature and slightly increases with increasing temperature at the same concentration. The density of the solution decreases with increasing temperature and water mole concentration.     

Improved Density Correlation for Supercritical CO2

An experimental apparatus was designed to measure accurately the density of supercritical CO₂ in wide temperature and pressure ranges. Based on experimental results, the curves for CO₂ density as function of pressure at certain temperatures were divided into linear‐growth, rapid‐growth, and slow‐growth intervals. The relative error between the experimental and calculated density values for a number of frequently used equations of state was evaluated. These equations were corrected after analyzing the accuracy of each equation in the different intervals. A new method for calculating the density of supercritical CO₂ that includes 28 constant parameters is proposed to determine the density at a known temperature and pressure.     

Calculation of Temperatures in Microwave-Heated Two-Dimensional Ceramic Bodies

Tempertures are calculated in a ceramic material exposed to microwaves. The method entails calculation of electromagnetic fields by integral formulation and subsequent solution of the heat conduction equation for temperature in a ceramic piece. The solution of the equation is numerical and the parameters used are estimates for properties of SiC. The results include a case where the complex dielectric constant is varied with temperature The computed results demonstrate that SiC can be heated to high temperatures (1000-1500 K) and that both the temperature and the temperature gradient can be controlled by varying the power density of the micro waves and the external cooling. The results also exhibit high sensitivity of temperatures to the dimensions of the material and the orientation in which microwaves impinge on the ceramic body.     

Physical and chemical stress relaxation of elastomers

In this paper we have developed a method whereby physical and chemical relaxation processes can be distinguished, using stress relaxation experiments as a function of temperature. We assumed that there exists some temperature range above the glass transition temperature over which the chemical effects can be neglected for the time scale of the experiments. The data in this low temperature range were then used to determine the WLF constants and other physical relaxation parameters. The physical component of the stress relaxation could then be subtracted from high temperature experiments in order to extract chemical kinetic information. Based on certain reasonable assumptions, an equation was developed for the relaxation modulus of a chemically reacting system. This equation could be used to determine the time dependence of the crosslink density, or conversely could be used to predict the long term relaxation modulus from an assumed kinetic mechanism. These calculations were demonstrated for ethylene propylene and butyl elastomers.     

Elasticity and Anelasticity of Uranium Oxides at Room Temperature: I, Stoichiometric Oxide

The elastic modulus and internal friction of stoichiometric uranium oxide at room temperature were studied using a dynamic method. The elastic modulus of stoichiometric urania at room temperature increases with increasing density. When the volume fraction porosity is less than 0.1, either linear or exponential equations can he used to calculate the elastic modulus as a function of density. When the volume fraction porosity is more than 0.1, a linear equation seems to be more suitable. The elastic modulus of stoichiometric nonporous uranium oxide at room temperature was found, by extrapolation, to be 2243.56 ± 22.1 kbars when the exponential equation was used, and 2233.85 ± 22.05 kbars when the linear expression was used. The internal friction of stoichiometric urania decreases sharply as the grains become larger. The number, size, and position of pores may also affect the internal friction values.