Poisson比为1/2材料中球形空穴突变和球形空穴萌生的分岔问题研究

研究Ｐｏｉｓｓｏｎ比为１／２的Ｈｏｏｋｅ材料中,空穴的突变和萌生现象·求解一个球对称几何非线性弹性力学的移动边界（ｍｏｖｉｎｇｂｏｕｎｄａｒｙ）问题,空穴为球形,远离空穴处为三向均匀拉伸应力状态,在当前构形上列控制方程;在当前构形边界上列边界条件·找到了这个自由边界问题的封闭解并得到空穴半径趋于零时的叉型分岔解·计算结果显示,在位移＿载荷曲线上存在一个切分岔型分岔点（或鞍结点型分岔点、极值型分岔点）,这个分岔点说明在外力作用下空穴会发生突变,即突然“长大”;当球腔半径趋于零时,这个切分岔转化为叉型分岔（或分枝型分岔）,这个叉型分岔可以解释实心球中的空穴萌生现象     

二维抛物型积分微分方程动边界问题的有限元方法

１引言抛物型积微分方程,可广泛用于描述具有记忆的材料的热传导、气体扩散、松散介质中的压力等实际问题中的现象,具有重要研究意义．关于固定空间区域上该类方程的研究,可见文献［１］,［２］;关于动边界抛物型方程,梁国平等已有重要工作［３］,［４］;作者在文［５］中,研究了一维动边界抛物型积微分方程的数值方法．本文研究二维空间区域变动情形下此类方程初边值问题的全离散、半离散有限元逼近格式及有关数值分析．主要特点在于对动边界和时间积分项（Ｖｏｌｔｅｒｒａ项）的处理．对于前者,通过空间变量代换,将问题化为定…     

移动床热煤气脱硫气固反应过程模拟——Ⅱ-错流移动床非催化气固反应过程模拟

基于前文错流移动床反应器模型方程,模拟计算并分析了该类反应器中气、固相流动对热煤气脱硫等非催化气固反应过程的影响。研究表明,床层在床深方向按反应速率的快慢可分为粗脱区和精脱区,在颗粒流动方向上气相浓度差异较大,并主要体现在粗脱区内,床层出口处颗粒转化率呈现较大分布,反应器内气固交错流动、气相浓度和颗粒转化率共同作用（ 于气固反应速率） 等因素是造成过程特征的主要因素。因此反应器优化应满足对两相流动的优化,将粗脱区设置成错流移动床而精脱区设置成固定床,并使粗脱区内颗粒流速沿气流方向逐渐减小,以减小出口颗粒转化率的分布并提高颗粒利用率,同时沿颗粒流动方向应逐渐减小过床气流体积分率以利于床内气固反应速率的均一分布。由此指出对该类床型其底部渐缩下料段和过床气流对床内颗粒流动的影响以及床层结构及颗粒流动对过床气流分布的影响研究的必要性。     

The perturbation parameter in the problem of large deflection of clamped circular plates

In the problems of large deflection of clamped circular plates under uniformly distributed loads, various perturbation parameters relating to load, deflection, slope of deflection, membrane force, etc, are studied. For a general perturbation parameter, the variational principle is used for the solution of such a problem. The applicable range of these perturbation parameters are studied in detail. In the case of uniformly loaded plate, perturbation parameter relating to central deflection seems to be the best among all others. The method of determination of perturbation solution by means of variational principle can be used to treat a variety of problems, including the large deflection problems under combine loads. This paper is completed under the guidance of Prof. Chien Wei-zang.     

The derivation of J-integral conservation law from the principle of virtual work

The general form of J-integral conservation law in three di-mensions has been derived from the principle of virtual work.The necessary conditions for J-integral conservation are alsogiven.     

LOAD CAPACITY OF OILFILM——LUBRICATED BALL-BEARING WITH SPIRAL GROOVES

In order to improve load capacity and stability of a fluid moving-pressure bearing, at present, measure of cutting grooves on a turning-shaft is generally adopted.The performances of spiral grooves are better in various groovetypes. Therefore, a theoretical analysis and an experimental investigation of the bearing with spiral grooves attract general attention. But the results of most articles published in china are numerical solutions of the computer. Using the methods of parameter perturbation in the paper, an approaching analytical solution of Reynolds equation of the moving-pressure oilfilm-lubricated ball-bearing with spiral grooves has been obtained. We have combined the numerical solutions of the computer, and the influence of the bearing parameters upon the load capacity is discussed; the optimum values of the groove parameter are obtained. The theoretical conclusion of this paper is in good agreement with the experimental data obtained by 651 Institute.     

30MeV/u 40Ar+115In反应中的IMF能谱

测量了30MeV/u ⁴⁰Ar束流轰击¹¹⁵In反应靶时出射的中等质量碎片(IMF)的能谱.通过比较在不同出射角度发射的同一种IMF的能谱,得到了IMF的发射机制随出射角的演化关系.在假定运动源速度和出射离子库仑位垒不随出射角变化的条件下,通过改变发射源的强度和核温度参量完成了对实验测得能谱的运动源拟合,并详细讨论了3个发射源所占份额和源强随出射角的演化关系.     

生产银杏黄酮的模拟移动床色谱工艺

世界各国银杏黄酮类药品的标度为总黄酮含量24％,生产工艺主要是浸取。现在国内有厂家提出制备高纯度银杏黄酮产品——总黄酮含量44％,生产工艺主要包括浸取和提纯两步,提纯主要采用树脂柱层析法。本文用模拟移动床色谱(Sinulated Moving Bed Chromatography,简称SMBC)提纯生产工艺,所得黄酮纯度可达90％以上。     

Numerical stability study and error estimation for two implicit schemes in a moving boundary problem

Two algorithms are described [Ferris D. H. (fixed time‐step method) and Gupta and Kumar (variable time‐step method)] that solve a mathematical model for the study of the one‐dimensional moving boundary problem with implicit boundary conditions. Landau's transformation is used, in order to work with a fixed number of nodes at each time‐step. The p.d.e. is discretized using an implicit finite difference scheme. The mathematical model describes the oxygen diffusion in absorbing tissues. An important application is the estimation of time‐variant radiation treatments of cancerous tumors. © 2000 John Wiley & Sons, Inc. Numer Methods Partial Differential Eq 16: 42–61, 2000     

Considerations on the spring analogy

This paper presents an investigation on the spring analogy. The spring analogy serves for deformation in a moving boundary problem. First, two different kinds of springs are discussed: the vertex springs and the segment springs. The vertex spring analogy is originally used for smoothing a mesh after mesh generation or refinement. The segment spring analogy is used for deformation of the mesh in a moving boundary problem. The difference between the two methods lies in the equilibrium length of the springs. By means of an analogy to molecular theory, the two theories are generalized into a single theory that covers both. The usual choice of the stiffness of the spring is clarified by the mathematical analysis of a representative one‐dimensional configuration. The analysis shows that node collision is prevented when the stiffness is chosen as the inverse of the segment length. The observed similarity between elliptic grid generation and the spring analogy is also investigated. This investigation shows that both methods update the grid point position by a weighted average of the surrounding points in an iterative manner. The weighting functions enforce regularity of the mesh. Based on these considerations, several improvements on the spring analogy are developed. The principle of Saint Venant is circumvented by a boundary correction. The prevention of inversion of triangular elements is improved by semi‐torsional springs. The numerical results show the superiority of the segment spring analogy over the vertex one for a small rotation of an NACA0012 mesh. The boundary correction allows for large deformation of the mesh, where the standard spring analogy fails. The final test is performed on a Navier–Stokes mesh. This mesh contains high aspect ratio mesh cells near the boundary. Large deformation of this mesh shows that the semi‐torsional spring improvement is imperative to retain the validity of this mesh. Copyright © 2000 John Wiley & Sons, Ltd.