绘制二元和三元系相图及热力学函数的通用程序

近几年来,相图和热力学函数的计算机绘制引起了人们的广泛注意。手工绘制复杂的二元和三元相图及热力学函数不仅工作量大而且常常会引起误差。如果要把计算相图或热力学函数和大量的实验数据相比较,手工绘制几乎是不可能的。我们在德国西门子公司的7570C计算机系统拥有的图形设备CALCOMP上编制了绘制二元和三元相图及热力学函数的通用FORTRAN程序,并用此程序绘制了大量的二元和三元相图及热力学函数,结果甚为满意。     

相图与相关热力学性质的综合分析方法

本文发展了一种将相图和其它相关的热力学性质放在一起关联的综合方法并实现了计算机程序化。该方法基于广义最小二乘原理,可以同时考虑多种不同来源、不同性质的原始数据,于同一拟合过程中得到所有的未知参数。结果,能够更加充分合理地利用原始数据,提取更多的信息,并且保证拟合结果在体系内彼此相容。对于线性拟合,文中给出一种由焓项、熵项和其他项三个加权部分构成的通用拟合关系式,以用于常见各类热力学性质和相平衡数据的变换。文中还给出回归Marquart二步参数优化法的结构框图和若干应用实例。     

优势区相图三维图形log Pi—log Pj—T的绘制

计算机绘制优势区相图通常是指如何根据优势区的裁决原理来绘制log P_i-log P_j或log P_i-T类的二维相图。为了考察它们随第三变量连续变化的情况,得到对所研究体系的热力学规律完整全面的了解,本工作以温度T为第三变量,在PC机上初步实现了三维优势区相图log P_i-log P_j-T的绘制。     

MeX—Me‘X2系熔盐相图中间相平衡液相线的计算机预报

应用原子参数－人工神经网络方法，预测ＭｅＸ－Ｍｅ’Ｘ２型熔盐系相图中与ＭｅＭｅ’Ｘ３或Ｍｅ２Ｍｅ’Ｘ４两种中间化合物固相成平衡时的液相线，结果与实测值颇符合。     

用理想化学理论对强溶剂化的二元合金系进行活度预测

本文广泛地探讨了利用理想化学理论对强溶剂化的二元合金系进行活度,超额自由能,混合自由能等热力学数据预测的可能性.对15种不同体系进行了计算和预测,它们是:(1)生成单个化合物的二元合金系;(2)生成两个化合物的二元合金系;(3)生成三个化合物的二元合金系;(4)生成四个化合物的二元合金系.本文为从相图获取较多的热力学数据提供了一个有效的方法.当选取合适的模型参数时,计算结果与实验数据吻合很好.     

RTlogP_2～T优势区相图的智能化程序系统

本文介绍了计算机绘制M-A-B体系的RTlogP_i～T(或logP_i～1/T)优势区相图的智能化程序系统,它是用FORTRAN语言编制的通用程序。此法具有要求用户输入信息量少,计算速度快,直接输出图形等优点。并对F_e-S-O,Cu-S-O,F_e-C-O及Pb-S-O等体系进行了数十张图的实例计算。     

一价金属卤化物熔盐系相图特征的规律及预报

用模式识别－人工神经网络结合学键参数的方法，对一价金属卤化物熔盐系相图特征的规律进行了总结和预防，预报结果与实验符合。     

计算机绘制三元系等活度图方法的研究

以三元系等活度线计算机绘制过程中出现的锯齿形问题,抓住常见等活度线的一般规律,提出一种新的三元系等活度线的计算方法。通过转换浓度变量,构造一组在计算范围内单调的方程,确保了绘图不出现锯齿形。此法原理简单,可用于各种热力学模型的等活度线计算。用于SReM热力学模型,并建立等活度图绘制程序。程序具有界面友好、应用灵活、实用性强的特点。用之于绘图,表明本文提出的方法,可有效避免出现锯齿形。     

广义简约梯度增强的遗传算法计算Ca2+-PO43--OH--F--CO32--H2O体系溶解度相图

溶解度曲线图对湿法合成氟取代羟基磷灰石有很重要的指导意义,但是这方面的数据资料很少,本文将描述Ca~(2 )- PO_4~(3-)-OH~--F~--CO_3~(2-)-H_2O体系平衡关系的强非线性方程组求解转变成最优化问题,用广义简约梯度(GRG)增强的遗传算法求解该体系的平衡关系,获得含氟磷灰石-水体系的溶解度相图。结果显示在pH=9附近处,磷灰石溶解度最小,Ca/P和Ca/F增加,磷灰石的溶解度随之增加,温度升高,磷灰石溶解度降低。     

CsF-CaF2系熔盐相图的计算机预报与实验测定

用支持向量机算法总结了已知的29个AF－BF2型二元熔盐系形成A2BF4的化合物与否的规律性。结果表明：若按已有的文献报道认为CsF-CaF2系不形成分子式为Cs2CaF4的化合物，则与其他29个系总结出的规律有矛盾。因此我们用差热分析和平衡固相的X－射线分析对该系相图重新测定，结果证明确实存在前人忽略了的异化熔化的中间化合物Cs2CaF4.     

平面自治系统相位图的MATLAB软件设计

围绕平面自治系统的相位图这个核心概念,利用MATLAB求解微分方程组的优势,得到了求解自治微分方程组相位图曲线、相位图方向场等各种算法的程序实现,实现了MATLAB仿真工具箱设计,利用图形用户界面(GUI)方法,设计了良好的人-机交互系统的主界面,最后给出了实际例子的程序运行结果,对推动微分方程组在具体实践中的应用和普及具有实际意义。     

Assessment of the temperature and pressure dependence of molar volume and phase diagrams of Cu and Zn

This study reports the thermodynamic assessment of the temperature and pressure dependence of molar volume of Cu and Zn, as well as their P–T phase diagrams based on the CALPHAD approach. The molar volume of fcc-Cu, hcp-Zn, and liquid phases as a function of both temperature and pressure was directly assessed from the data reported in the literature by implementing the CALPHAD-compatible equation of state (EOS). This EOS incorporates the quasi-harmonic model to eliminate the spurious predictions of negative heat capacity and thermal expansion at high pressure. Furthermore, the P–T phase diagram of each element was determined on the basis of the experimental results and calculated parameters. The experimentally estimated thermodynamic values are in good agreement with the calculated results.     

Application of CALPHAD to high pressures

The current methods of performing CALPHAD (CALculation of PHAse Diagrams) calculations of high-pressure phase equilibria often lead to spurious predictions of negative thermal expansion or negative heat capacity at high pressures. It is shown that the origin of the problem lies in an incompatibility between the temperature dependence of the widely used SGTE (Scientific Group Thermodata Europe) database and that of typical equations of state of the Mie–Grüneisen type. This inconsistency is also linked to the general problem of describing mechanical instability in CALPHAD. In the present work, a new free energy formulation is developed specifically for inclusion of pressure effects in CALPHAD methodology. It is based on an interpolation between SGTE data at low pressures and the quasiharmonic lattice model at high pressures. The new formulation is constrained to physically credible predictions of the thermophysical properties, while preserving the simplicity of the CALPHAD method. Examples are given of calculations of thermophysical properties and high-pressure phase equilibria in Al, Si, MgO, Fe and the Al–Si binary alloy system.     

基于相图几何特征的夹芯梁蒙皮裂纹识别方法

通过分析主共振发生时,含蒙皮呼吸裂纹与无裂纹的金字塔型点阵夹芯梁的相图几何特征,提出一种基于相图几何特征的裂纹参数识别方法.首先,采用"像素法"计算相图面积,利用定义的"准标准差公式"描述含裂纹夹芯梁相图面积的相对变化量,并定义相图面积参量为含裂纹与无裂纹相图面积之差和准标准差的比值,分析了该相图面积参量随裂纹位置和裂...     

Calculation of the T–P phase diagram for oxygen using the mean field theory

T–P phase diagram of oxygen with the liquid and solid phases (α, ά, ᾱ, β, γ and ϵ) is calculated using the mean field theory. By expanding the free energy in terms of the order parameter, the phase line equations are derived and they are fitted to the experimental T–P data from the literature.Our calculated T–P phase diagram predicts adequately the observed behavior of the transitions between the liquid and solid phases in oxygen (O₂). Some thermodynamic quantities are predicted from the free energy expansion for the liquid–γ and ά–ɛ transitions in O₂.     

Thermodynamic assessment of the Bi-alkali metal (Li,Na, K,Rb) systems using the modified quasichemical model for the liquid phase

Bi-alkali metal (Li, Na, K, Rb) binary systems have been systematically assessed based on the available phase diagrams and thermodynamic data. The modified quasichemical model, which takes short-range ordering into account, is used to describe the liquid phase. All intermetallic phases are treated as stoichiometric compounds. A set of self-consistent model parameters is obtained and the experimental data are reproduced well within experimental error limits. The enthalpy of mixing, entropy of mixing, and activity of element are calculated, showing the liquid phase exhibits maximum short-range ordering at 75 at% X (X=Li, Na, K, Rb). Some systematic variations and regularities are presented, indicating the enthalpy and entropy of mixing for the liquid phase at the maximum short-range ordering along with the enthalpy of formation and melting temperature of intermediate compound BiX₃ change with the atomic radius of alkali metals regularly.     

基于组件的市场交易结算信息管理系统的研究

分析了市场交易结算信息管理系统的三种交易行为,包括本地交易、网上交易和电话订单,使用用例图描述了系统的功能,使用部署图描述系统的硬件体系结构,简要分析了系统采用的B／C／S三层架构,对系统组件的三层架构进行了设计。     

Thermodynamic evaluation and optimization of Al-La, Al-Ce, Al-Pr, Al-Nd and Al-Sm systems using the Modified Quasichemical Model for liquids

The Al-La, Al-Ce, Al-Pr, Al-Nd and Al-Sm (Al-light rare earth) binary systems have been systematically assessed and optimized based on the available experimental data and ab-initio data using the FactSage thermodynamic software. Optimized model parameters of the Gibbs energies for all phases which reproduced all the reliable experimental data to satisfaction have been obtained. The optimization procedure was biased by putting a strong emphasis on the observed trends in the thermodynamic properties of Al-RE phases. The Modified Quasichemical Model, which takes short-range ordering into account, is used for the liquid phase and the Compound Energy Formalism is used for the solid solutions in the binary systems. It is shown that the Modified Quasichemical Model used for the liquid alloys permits us to obtain entropies of mixing that are more reliable than that based on the Bragg-Williams random mixing model which does not take short-range ordering into account.     

安全协议的串空间图表示

串空间是安全协议的一种形式化描述，串空间图是它的图示化表示．定义开丛为串空间图的构造单元，并在开丛集上定义前缀算子和组合算子．通过开丛之间的前缀和组合运算，给出了无穷并发运行安全协议串空间图的生成方法．定义了开丛互模拟以及串空间图之间的互模拟等价关系，并给出用于消除串空间图冗余结构的化简规则＋案例分析和与相关工作的比较表明，无冗余的串空间图为无穷并发运行安全协议的安全属性验证提供了一个有效的分析模型．     

三元相图中字符提取算法

针对三元相图的特点,提出了一种基于轮廓跟踪的文图分离方法,通过轮廓跟踪得到每个连通域的外接矩形,分离出大小在一定范围内的外接矩形,从而实现文字与图形的分离。