改良BBS法评价聚氨酯发泡催化剂

改良BBs法用光电法测发泡高度-时间曲线,用机械手完成投掷钢球动作,过程用微机控制。本文对此法测得的三乙胺、四甲基乙二胺、二甲基乙醇胺、双(二甲基氨基乙基)醚、三乙烯二胺等催化剂在聚氨酯软质泡沫塑料形成过程中的胶化-发泡曲线进行了讨论,并评价了它们的催化特性。改良BBs法与手工BBs法相比,具有检测精度高,样本采集点多的优点。     

用改进扩展有限元法研究重力坝强震断裂过程

采用改进的扩展有限元法(Extended Finite Element Method,XFEM),即引入虚结点的XFEM,在静力功能基础上实现了动力断裂分析功能,并用于强震中结构多条裂缝的同时扩展分析。采用混凝土Ⅰ型和Ⅰ-Ⅱ混合型动力断裂试验进行了精度验证,然后将该方法应用于Koyna坝的地震开裂分析。结果表明,这一方法在求解混凝土Ⅰ型和Ⅰ-Ⅱ混合型动力断裂问题方面具有良好精度,其避免了网格不断重剖分的问题,也无需采用开裂单元的子域积分来描述非连续位移场,即可实现单元内连续断裂过程的模拟。     

A regularization method for a Cauchy problem of Laplace's equation in an annular domain

In this paper, we propose a new regularization method based on a finite-dimensional subspace generated from fundamental solutions for solving a Cauchy problem of Laplace's equation in an annular domain. Based on a conditional stability for the Cauchy problem of Laplace's equation, we obtain a convergence estimate under the suitable choice of a regularization parameter and an a-priori bound assumption on the solution. A numerical example is provided to show the effectiveness of the proposed method from both accuracy and stability.     

Parallel R-Point Explicit Block Method for Solving Second Order Ordinary Differential Equations Directly

A new parallel R-point explicit block method for solving second order ordinary differential equations (ODEs) directly is developed. The method computes the numerical solution of the equations at three points simultaneously. Each problem was tested on the shared memory parallel computer Sequent S27 using both the sequential and parallel implementations of the new method and the conventional 1-point method. Numerical results are presented comparing the two methods in terms of the number of steps taken, accuracy and execution times. The results indicate the advantages of using the parallel implementation of the new method for solving second order ODEs directly particularly when the step size becomes finer.     

Removal of Contrived Chaos in Finite-difference Methods

A chaos-free numerical method will be developed for the solution of a system of non-linear initial-value problems (IVP's) associated with the transmission dynamics of two HIV subtypes. It will be shown that integration of this four-dimensional system with some standard numerical integrators like the fourth-order Runge-Kutta algorithm leads to scheme-dependent numerical instabilities.     

Basic Lul Factorization And Improved Iterative Method With Orderings

Consider the 'basic LUL factorization' of the matrices as the generalization of the LU factorization and the UL factorization, and using this LUL factorization of the matrices, we propose an "improved iterative method" such that the spectral radius of this iterative matrix is equal to zero, and this method converges at most n iterations. Our main concern is the necessary and sufficient conditions that the improved iterative matrix is equal to the iterative matrix of the improved SOR method with orderings. Concerning the tridiagonal matrices and the upper Hessenberg matrices, this method becomes the improved SOR method with orderings, and we give n selections of the multiple relaxation parameters such that the spectral radii of the corresponding improved SOR matrices are 0. We extend these results to a class of $n \times n$ matrices. We also consider the basic LUL factorization and improved iterated method 'corresponding to permutation matrices'.     

Unconditionally stable C1-cubic spline collocation method for solving parabolic equations

This article aims to present a new approach based on C¹-cubic splines introduced by Sallam and Naim Anwar [Sallam, S. and Naim Anwar, M. (2000). Stabilized cubic C¹-spline collocation method for solving first-order ordinary initial value problems, Int. J. Comput. Math., 74, 87–96.], which is A-stable, for the time integration of parabolic equations (diffusion or heat equation). The introduced method is an example of the so-called method of lines (the solution is thought to consist of space discretization and time integration), which is an extension of the 1/3-Simpson's finite-difference scheme. Our main objective is to prove the unconditional stability of the proposed method as well as to show that the method is convergent and is of order O (h ²)?+?O (k ⁴) i.e. it is a fourth-order in time and second-order in space. Computational results also show that the method is relevant for long time interval problems.     

基于有限元法的斜齿轮齿条啮合接触分析

通过Solidworks软件建立了斜齿轮齿条模型.采用有限元法和Solidworks Simu-lation有限元软件计算最恶啮合接触区域以及齿轮齿条啮合时齿根上最大的弯曲应力和接触区域上的接触应力.通过理论经验计算应力公式与有限元法计算的应力值相比较,以验证通过最恶啮合接触区域计算接触应力的可行性.     

基于DEA模型的我国上市商业银行效率研究

本文采用了数据包络分析（DEA）方法研究我国上市商业银行的经济效率,结果表明：我国上市商业银行的全要素生产率（TFP）和技术效率都偏低,国有四大行的整体技术效率也明显低于股份制商业银行,我国银行业的经营管理与技术水平稳定性较差。最后文章提出几点关于银行业发展的建议。     

医师科技创新能力评价指标构建

本文运用文献分析法、Delphi法和层次分析法筛选和确定了医师科技创新能力指标体系。该评价体系包括专业教育背景、知识创新能力、技术创新能力和学术交流能力4项一级指标,11项二级指标,部分二级指标又细分为三级指标,对每一指标给出相应权重系数和内涵,并对各项指标提出量化方法。