泊松方程数值解法的加速收敛法

用数值方法对泊松方程求解时，往往要对迭代的中间结果作适当的压缩处理，以加快收敛速度和避免溢出。本文提出一种单一指数因子的非线性压缩法。一维数值模拟结果表明，平衡态时不必进行压缩处理。而在非平衡态时，最佳指数压缩因子的大小与杂质浓度有关。参考本文给出的数值计算结果，根据给定器件的杂质浓度分布，选定一最佳指数压缩因子，可以使泊松方程的数值求解过程具有最快的收敛速度。     

纤维共晶生长界面前沿三维扩散场解析

修正Ｊａｃｋｓｏｎ和Ｈｕｎｔ关于在垂直生长方向截面上溶质扩散各向同性假设，求解三维Ｌａｐｏｌａｃｅ方程，获得纤维共晶生长界面前沿三维稳态扩散场，并证明Ｊａｃｋｓｏｎ和Ｈｕｎｔ的二维模型是实际生长的二维简化和一阶近似，并用丁二腈（ＳＣＮ）一梓脑（ＣＡＭ）纤维共晶系统计算生长界面前沿溶质分布。     

（yxl）φ切压电石英谐振器振动模式分析

从压电方程，动力学方程入手，分析了（ｙｘｌ）φ切石英谐振器的厚度切变振动，利用自由边界条件及串联与并联谐振时的电学条件，求出了并联谐振频率和串联振频率，讨论了实测频率与频率公式存在一定偏差的原因。     

WAVELET ALGORITHM FOR INTEGRAL OPERATOR EQUATION AND ITS APPLICATIONS TO ELECTROMAGNETIC PROBLEMS

A brief summary of the basic theory of wavelet is proposed. The properties of wavelet function are discussed. The possible applications of wavelet to electromagnetics are given. Examples show that the wavelet method is feasible and effective for solving electromagnetic problems.     

关于不确定的对称组合系统的稳定化控制器与观测器的设计

本文研究了不确定的对称组合系统的稳定化控制器与观测器的设计问题，给出一种设计稳定化控制器与观测器的方法，在这种设计方法中，使给定的带有不确定性的对称组合系统稳定的状态反馈增益矩阵和观测器增益矩阵可由低阶代数Ｒｉｃｃａｔｉ方程的解导出。     

Phase equilibria of crude oils using the continuous thermodynamics approach

This paper deals with the application of continuous thermodynamics to light and heavy oil systems using the Peng- Robinson equation of state. The composition of the high molar mass components in a reservoir oil is described by a continuous distribution function of some characterizing quantity, e.g. molar mass or boiling temperature. Numerical Gaussian quadrature methods are used to generate pseudo-components and their mole fractions from distribution data. Several examples are presented for phase equilibria of solvent/crude oil systems. The results showed that semi-infinite distribution functions, such as the Γ function, cannot be applied to all cases, e.g. dew point calculations. The Gauss- Legendre quadrature method coupled with spline fitting worked best for heavy oil systems.     

Experimental and mathematical studies of natural convection for solid-salt dissolution in water

The phenomena of natural convection caused by a concentration gradient usually creates currents as a result of buoyancy forces. These forces are formed from the combined effect of a fluid density gradient and the body force (gravitational force). The above phenomenon was studied experimentally in a circular glass column of 0.08 m diameter and 1 m length. This column was erected vertically and filled with distilled water with a salt bag placed on top of it and partially immersed in water. The dissolution mechanism was then modelled and a finite difference method was used to solve the formulated equations by using the implicit scheme of MacCormack (Anderson et al., 1984). The experimental results and the numerical predictions are represented graphically and give compatible agreement.     

A BOUNDARY INTEGRAL EQUATION AND ITS NUMERICAL SOLUTION OF POTENTIAL FLOW AROUND SURFACE-IRREGULA-RITIES

In this paper,using complex functional theory,the authors turn the potentialflow around the surface irregularities in a pressure conduit and semi-infinite platforms intoDirichlet problem.Based on Schwarz formula and by the application of Plemelj's formula,theauthors change the problem into the integration of a Cauchy boundary integral equation in theflow plane through the substitution of variables.Using numerical integration,the authors obtainthe velocity distribution and pressure coefficient along surface irregularities and platforms.Thephysical concept of this method is clear,the convergent speed is rapid and the computative effi-ciency is high.The calculated values agree well with the measured results.It is an effective andsimple method in solving potential flow.     

二维金属凹槽填充各向异性介质时散射的边界元方法:TE情形

由各向异性介质无界空间Green函数和Green恒等式出发，推导了TE波入射时二维任意截面金属凹槽填充各向异性介质时所满足的边界积分方程，并用边界元法和广义网络原理计算了金属凹槽填充各向异性介质时的散射。用文中方法退化计算了凹槽填充各向同性介质时的散射，计算结果与解析结果一致。并给出了凹槽填充各向异性介质时的散射算例。     

单元系T—p相图的数学结构

作者以化学元素的稳定单质为基准,推演出了任意物质M_i(相态Ω)的热力学生成活度{相态Ω)的函数形式:?D_Ω数值的大小体现着相态Ω的热力学相对稳定性.根据集合论原理沿D(稳定性)座标取极大值的方法把物理性质互不连续的各个异相态连结在一起,建立了单元系在T-p面上的优势分布方程(PSDE):■作者以H_2O为实例,计算了T-p相图,与实验相图基本一致.