Linear Algebra Considerations for the Multi-Threaded Simulation of Mechanical Systems

A solution method suitable for the multi-threaded simulation ofmechanical systems represented in Cartesian coordinates isproposed and analyzed. In a state-space framework for thesolution of the Differential Algebraic Equations (DAE) ofMultibody Dynamics, the position/velocity stabilization and theacceleration computation are based on iterative solvers applied toequivalent reduced problems. The most in-depth computationalaspect analyzed is the preconditioning, i.e., the direct solutionof the reduced systems. Provided a topology index reduction is first applied to the model, the effort for the direct solution of the reduced systems is shown to be of order O(N _J ), where N _J is the number of joints in the model. The recurring theme of thepaper is the central role that the topology of the mechanicalsystem plays in the overall performance of the numericalsimulation. Based on the topology of the model, parallelcomputational threads can be established to start in the equationformulation and continue through the iterative numericalalgorithms employed for the numerical solution. Task schedulingthese parallel threads is expected to redeem real-time performancefor certain classes of complex applications.     

油管漏磁探伤工艺与应用

简要介绍了漏磁探伤的基本原理及工艺流程与设备仪器，并对油管的常见损伤缺陷进行了分析。     

CHA无机凝胶体系的研究及应用

过去低渗油藏调剖，注入性和堵塞性很难统一，新研制的CHA无机凝胶体系是一种易注入、堵塞能力强的调剖剂，而且成胶时间在一定范围内可控。研究了配比、温度对CHA无机凝胶体系成胶时间的影响，成胶前的注入性，成胶后在高温高盐条件下的堵塞能力，得到了可应用于现场的CHA无机凝胶体系。该调剖剂在濮城油田沙三段和文卫结合部等高温、高盐低渗油藏应用后，取得了很好的效果。     

Mixed formulation of nonlinear beam on foundation elements

This paper presents an inelastic element for the analysis of beams on foundations. The element is derived from a two-field mixed formulation with independent approximation of forces and displacements. The state determination algorithm for the implementation of the element in a general purpose nonlinear finite element analysis program is presented and its stability characteristics are discussed. Numerical studies are performed to compare the model with the classical displacement formulation. The studies confirm the superiority of the proposed model in describing the inelastic behavior of beams on foundations.     

一种应用于二次布局的有效划分方法

提出了一种基于二次布局的结合MFFC结群和hMETIS划分的算法.实验表明:这种方法能得到很好的布局结果,但是运行消耗的时间比较长.为了缩短划分在二次布局中运行的时间,提出了一种改进的结群算法IMFFC,用它在二次布局中做划分.与前者相比较,这种方法虽然布局质量稍差,但速度更快.     

COPART:一种面向约束条件的自适应软硬件划分算法

本文介绍一种将自适应算法、遗传算法和列表调度算法结合起来应用于软硬件划分问题的算法COPARTART，并提出了一种基于约束条件的开销系数自适应调整方法，该方法所获得的划分结果能够良好体现设计目标。     

液位测量吹气装置的研究

介绍吹气法测量液位、界面、密度的原理；导出测量液位、密度的函数表达式及密度补偿的液位修正函数。给出吹气装置的基本组成；设计吹气装置的模拟试验系统；讨论模拟实验的结果；指出吹气装置应用中应注意的事项。     

利用C++Builder 5.0开发原理框图绘图软件

介绍了原理框图各种图形的数据存储方法，利用C^ Builder5.0开发了原理框图的绘图软件，实现了原理框图绘制的基本功能。     

爆炸焊接边界效应的力学能量原理

在爆炸焊接工艺中,存在一种称为边界效应的物理现象。即在一般情况下,在爆炸焊接后的复合材料中,会出现雷管区不复、其余周边被打伤、打裂和变形严重等问题。这些问题严重地影响着这类材料的质量。该文从传统的和经典的力学及能量原理出发,探讨了边界效应产生的力学 能量原理,并且提出了预防的措施。     

机械定尺飞锯机中的555时基电路

介绍了５５５时基电路在机械定尺飞锯机中的应用及工作原理。