三元物系液-液平衡计算的Fsolve算法

本文基于MATLAB优化工具箱中的fsolve算法,提出了一种计算三元物系液-液平衡数据的新方法.应用该方法预测了水(1) 醋酸(2) 氯仿(3)物系在298 K,308 K和318 K的液-液平衡数据,并将298K的液-液平衡数据与文献数据进行了比较,它们非常一致.在本论文中,应用UNIFAC液-液平衡模型,采用H2O,CH3,COOH和CHCl3基闭相互作用参数计算该物系共轭相中各组分的活度系数,获得了多组结点数据及相的比率.各温度下计算结果显示:各三元液-液相平衡模型约束方程的剩余均接近于零向量,数量级在10-4以下.Other-Tobias关联得到线性相关系数分别足0.9863,0.9939和0.9976.总之,本算法的可靠性,稳定性适用于计算三元液-液相平衡,计算实例所得结果经过检验是正确的.     

基于GM(0,N)模型的三元区间数序列预测

在工程和经济领域,很多数据序列具有很强的振荡性,这些振荡序列用区间数表示将包含更多信息.三元区间数不仅包含系统特征的上下界,还在中间增加一个偏好值,对三元区间数序列的预测研究具有很好的应用价值.为了使灰色模型GM(0,N)能够直接对三元区间数序列建模,改进了GM(0,N)模型方程的参数设置,将整体贡献系数和滞后项系数取为精确数,而将线性修正项系数和补偿系数设为三元区间数,从而对三元区间数的不同界点进行线性修正和补偿.进一步,为了提高对振荡序列的预测精度,结合马尔科夫预测和序列转换方法对模型的预测序列进行修正. 通过对我国用电量和社会消费品零售总额的预测,表明了所提出的三元区间数多变量灰色模型比单变量灰色模型和区间数序列转换为精确数序列再预测的方法效果更好.     

Assessment of diffusion mobility for bcc phase of Ti–Al–Ni ternary system

The experimental diffusion coefficients of the Ti–Ni binary and Ti–Al–Ni ternary bcc phase were critically evaluated to assess the diffusion mobilities by the DICTRA-type phenomenological treatment. The calculated diffusion coefficient shows reasonable consistency with the diffusion coefficient extracted in the experiment, including the impurity and inter-diffusion coefficients in bcc Ti–Ni binary alloy and the main interdiffusion coefficient in bcc Ti–Al–Ni ternary alloy. The difference between the calculated and experimental ternary cross coefficients is within appropriate relative errors. The predicted composition profiles and diffusion paths reasonably represent the diffusion processes that occur in Ti–Ni binary and Ti–Al–Ni ternary diffusion couples, thereby validating the mobility database assessed in the present work.     

醋酸丁酯-糠醛-水体系逆流萃取模拟计算

测定了糠醛—水、水—醋酸丁酯两个二元体系及醋酸丁酯—糠醛—水三元体系在不同温度下的液液平衡数据,由所测数据推算出三元体系UNIQUAC方程的模型参数,并证明了UNIQUAC方程可以较好地关联醋酸丁酯—糠醛—水体系的液液平衡。以UNIQUAC方程为模型,运用微机模拟计算了以醋酸丁酯为溶剂,萃取分离糠醛水溶液的分离结果,结果表明,在理论板数N=15时,糠醛收率达98.2％,证明醋酸丁酯是比较合适的萃取溶剂,为糠醛生产工艺改造提供了理论依据。     

一种预测混合物共沸组成的新方法

提出了一种预测二元及三元物系形成共沸点的新方法。共由沸点定义,推导出二元及三元物系形成共沸点的条件,以及共沸点个数是奇数还是偶数。在存在共沸点的条件下,利用活度系数关联式,通过泡点计算求出共沸条件。实例计算结果表明,预测结果与文献结果基本一致。     

四元体系Na~+/Cl~-、SO_4~(2-)、CO_3~(2-)-H_2O和Na~+、K~+/Cl~-、CO_3~(2-)-H_2O25℃溶解度的计算

本文利用HW公式以盐的溶度积为平衡判据,对四元体系Na~+/Cl~-、SO_4~(2-)、CO_3~(2-)-H_2O和Na~+、K~+/Cl~-、CO_3~(2-)-H_2O以及所包含的三元和二元体系25℃的溶解度和水活度进行了计算,修正和补充了这两个四元体系的实验结果。     

正己烷-甲基环戊烷-邻苯二甲酸二丁酯三元体系汽液平衡研究

测量了不同压力下正己烷-甲基环戊烷-邻苯二甲酸二丁酯三元体系等压汽液平衡数据，确定了该体系Wilson方程模型参数，并以Wilson方程为汽液平衡模型，采用微机模拟计算了以邻苯二甲酸二丁酯为溶剂，萃取精馏分离正己烷-甲基环戊烷混合物的分离结果，结果表明，萃取精馏分离该混合物效果良好。     

Osmotic and activity coefficients in the solutions of 1- and 2-naphthol in methanol and ethanol at 298.15 K

The osmotic coefficient of the solution, activity of the solvent and activity coefficient of the solute in solutions of 1- and 2-naphthol in methanol and ethanol have been measured by the isopiestic method. The experimental osmotic coefficient data were correlated using the Non-Random Two Liquid model (NRTL), the Non-Random Factor model (NRF), the two suffix Margules equation and a polynomial in terms of the molality of the solute. The models give reliable results for the correlation of the osmotic coefficient data. The activity coefficients of 1- and 2-naphthol were evaluated according to the considered methods using the parameters obtained by the correlation of osmotic coefficients.     

改进的Marquardt算法研究制膜液三元相图

在制膜液三元相图的计算研究中，非线性方程组解经常出现无意义解。为了避免该问题，本工作以Flory-Huggins理论为基础，推导出浊点线(binodal)方程和旋节线(spinodal)方程，先确定富相中聚合物体积分数为独立变量，然后应用更新雅可比矩阵及其逆的技巧，并应用本工作改进了的Marquardt算法，得出非线性方程组的有意义解。本工作还推导出成膜过程连续相组成迹线(pathline)方程。通过计算绘出了浊点线、旋节线和连续相组成迹线，并用于分析聚合物膜的成膜机理。     

Entropic-FV修正模型预测聚合物体系溶胀行为

Entropic-FV（EFV）修正模型是对原模型的自由体积分数项进行修改而获得,前者与后者具有相同的统计力学基础,且表达式简单,无需增加模型参数。将其用于聚乙二醇／甲醇二元体系中组分活度的计算,或与UNIQUAC-HB模型结合对聚乙烯醇膜／乙二醇／水和聚氨酯／正己烷／苯三元体系的溶胀平衡组成进行预测,并与EFV和原修正模型的预测结果以及文献值进行比较,结果显示该模型预测的准确度最高、稳定性较好。     

三元分子体系的过量摩尔体积：基于人工神经网络的表达和预测

以二元混合物体系的实验数据为基础，通过神经网络表达混合物组成与过量摩尔体积的定量关系，进而推测三元混合物体系和过量摩尔体积，本文研究了１６个极性和非极性混合物体系，对其对摩尔体系的预测结果优于Ｒａｓｔｏｇｉ方程的计算结果，表明神经网络可以作为一种推测三元混合物体系过量摩尔体积的工具。     

电解质溶液相平衡热力学模型研究进展

从电解质溶液理论、活度系数模型和状态方程出发，对用于电解质溶液相平衡关联、预测的成功模型及近年来应用研究的进展，以工程应用模型为重点，进行了综述。从长程静电作用和非静电作用对活度系数的贡献的角度，介绍了活度系数模型中，以Debye-Hueckel理论和MSA理论为基础的长程静电作用项的进展，介绍了Pitzer方程、E-NRTL、E-UNIQUAC以及化学贡献等活度系数模型的研究与应用进展；电解质状态方程则从3个方面总结了近年来的研究进展，即：以三次型方程、微扰理论为基础的电解质溶液状态方程和高温超临界条件下电解质溶液状态方程。     

The calculation and application of R function in ternary systems

The application of R function to the calculation of activities in a two-phase region in ternary systems is presented, which is simple and make the continuous calculation of activities from a homogeneous region to a two phase region easy. In order to extend the application of R function method to the calculation of the ternary modified Gibbs-Duhem equation, a new calculation formula is also derived.     

A Simple and Quick Method for Determination of Oxygen Debt Contracted During Physical Effort

An attempt has been made to evolve a simple and quick method of oxygen debt estimation from moderate to heavy exercise. The fast and slow components of oxygen debt recovery curve are known to be exponential with respect to time, but with different velocity constants. In the present communication the resultant of the two components has been closely approximated by a single exponential function with respect to some fractional power of time leading to a composite oxygen recovery equation of the form Y= Ym[l — exp( — k√t) ]. It has been proposed to estimate oxygen debt for a period of 32?minutes with the help of this equation based on 2-minute and 8-minute observations of extra oxygen uptake in moderate to heavy exercise. This equation has been validated against 43 observations on 34 subjects at sea level and high altitude. Results demonstrate reasonably good predictions. A nomogram for calculating oxygen debt has also been worked out on the basis of the proposed equation. Suitability of the approach for oxygen debt determination during very severe forms of exercise has been discussed.     

Thermodynamics of aqueous and water-organic solutions of electrolytes from very dilute to saturated concentrations

The solutions of electrolytes in water such as NaCl in H₂O are treated as a binary system of NaCl---H₂O. Only at very low concentrations does dissociation into Na⁺ and Cl⁻ becomes significant. This is similar to copper, where only a small fraction of the electrons participate in electronic conduction. The Hoch-Arpshofen model is applied to calculate the activity coefficient Tin Y of NaCl and other electrolyes in water. At high concentrations the interaction parameter is W 2, (NaCl), W is the interaction energy, 2 is the size of the complex, and (NaCl) is the molecule with the mole fraction x in our model. A solution with a complex size of 2 is a regular solution. At very low concentrations, x, NaCl (mole fraction) < 0.01, another term W m, (H2O) is required, with m = 200 or higher. In this case we have a complex made up of 199 molecules of water and one molecule of NaCl, indicating dissociation of NaCl into Na⁺ and Cl⁻. The application of this approach is supported by the fact that the activity coefficient of HCl in organic-water solutions deviates at lower and lower concentrations from the regular solution approach, as the organic concentration increases. This approach also calculates the activity coefficient of water. Because the salts are not completely miscible with water, a constant is added, to set the activity to one, when the solubility limit is reached. In treating ternary and larger solutions, such as CaCl₂---KCl---NaCl---H₂O the interaction between CaCl₂ and NaCl etc is calculated from the binary CaCl₂---NaCl phase diagram.     

变系数广义KdV-Burgers方程的精确类孤子解

利用一种函数变换将变系数广义KdV-Burgers方程约化为非线性常微分方程(NLODE),并由此NLODE出发获得变系数广义KdV-Burgers方程的若干精确类孤子解。由此可见,用这种方法还可以求解一大类变系数非线性演化方程。