一种自然网格的生成算法研究与应用

装配体在工作时应视为一个整体,其受力分析与单个零部件的分析不同,需要考虑零部件之间连接部位的受力分析。针对框架类装配体的特点,结合装配体零部件之间的连接关系,提出一种装配体自然网格生成算法,并在CAA平台基础上实现了这种自然网格单元的生成,从而得到装配体的骨架模型,即有限元分析模型。实践证明:该方法在框架类装配体模型的有限元分析中是切实可行的。     

分析非线性电路的谐波平衡法的改进

本文根据分析微波非线性电路的基本方法之一谐波平衡法,提出了一种加速收敛过程的改进方法,并且将其应用于微波混频器的非线性分析。在分析过程中引入了混频二极管非线性特性由时域到频域的简化变换技术,大大加快了计算速度。分析结果与已发表的结果相比较,一致性较好。这种改进的分析方法也可以推广应用于包含多个非线性器件的非线性电路的计算机辅助分析。     

计算机辅助成绩分析系统的设计与开发

介绍了一种在Windows操作系统下 ,利用VF编程语言开发的计算机辅助成绩分析系统。该系统可通过对分析参数的计算 ,自动绘制成绩分布曲线 ,对学生成绩及试卷质量做出全面客观的评价     

基于三维模型的飞机钣金零件检验特征提取技术

针对飞机钣金零件特征提取问题,提出一种以特征遍历进行特征提取的新方法.利用CATIA三维模型,在CATIA平台上,以VS2005工具和CATIA的应用组件架构(Component Application Architecture,CAA)调用CATIA的API函数,对CATIA进行二次开发.利用特征匹配技术,比较Excel表格中的特征与钣金零件的三维模型特征,准确地提取钣金零件三维模型的特征(如肋孔、表面类等),使钣金检验规划时间大约缩短20%,提高了钣金检验规划效率.     

飞机钣金特征的智能三维标注技术

采用CAA对CATIA进行二次开发,建立了钣金零件的检验规划系统.通过钣金零件的检验规划系统得到特征的检验方法,并将所有特征对应的检验方法通过智能三维标注技术,标注到三维模型上.智能三维标注,即通过人机智能交互的方式,将所有的检验信息全部表示在三维图上,简单,直观,明了.     

TDA4501—TDA3565亮度通道CAD优化设计

本文概要介绍如何通过CAA及CAD提高图像分辨率。     

高压BCD集成电路中高压功率器件的设计研究

高压功率集成电路的设计与制造因其具有的高技术难度而极具挑战性。所谓高压功率集成电路 (HV-PIC) ,是指将需承受高电压 (需达数百伏 )的特定功率晶体管和其它低压的控制电路部分兼容 ,制作在同一块 IC芯片上。文中以器件模拟软件 Medici为工具 ,用计算机仿真的方法 ,研究了高压 BCD电路中高压功率器件的设计问题 ,其中包括器件结构、掺杂浓度、结深等主要参数及其它一些技术因素对器件耐压的影响 ,并给出了相应物理意义上的分析。根据这一设计 ,在国内进行了一块高压功率 BCD集成电路的试制 ,经测试 ,耐压超过 660伏 ,输出功率 40 W,且电路的其它器件参数达到设计值 ,IC电路整体功能正常 ,所有参数达标     

多端口功率分配器S参数的计算机分析

本文给出复杂网络任意端口连接理论，从而可以方便地进行多端口功率分配器的Ｓ参数计算机分析，理论计算与实测结果作了比较，这一理论也适用于其它多端微波元件的分析。     

COMPUTER-AIDED ANALYSIS OF WAVE DIGITAL FILTER TRANSFER CHARACTERISTIC

An approach for finding the wave digital filter transfer characteristic is developed with ageneral computer program.The program can be used to analyse the quantification effect of differentmultiplier coefficient wordlengths for the wave digital filter transfer characteristic,thus it is possible to make areasonable choice of coefficient word-length in order to take account of economization as well as technicalspecifications when the wave digital filter is in hardware implementation.     

Analysis of changes in coordinate measuring machines accuracy made by different nodes density in geometrical errors correction matrix

Advances in modern manufacturing techniques increase production efficiency but, at the same time, present new tasks and challenges for coordinate metrology and the manufacturers of Coordinate Measuring Machines (CMMs). The main goal of current research efforts is improving measurement accuracy. Seeing as many of the possible solutions regarding CMM construction had already been explored, there seems to be little left for improvement in that field. Further efforts at accuracy improvement rely mostly on using sophisticated mathematical algorithms designed to correct relevant errors. Many types of errors could be compensated using this approach, including: probe head errors, machine dynamics errors and, most importantly, machine geometrical errors. Almost all coordinate measuring machines produced nowadays are equipped with geometrical errors compensation matrix known as the CAA matrix (Computer Aided Accuracy).CAA matrices are based on a grid of reference points (nodes) in which certain values of the components of geometrical errors are determined experimentally. The error values between the nodes are estimated using simple interpolation methods. Theoretically, a higher density of reference points on the grid describing the CAA matrix should improve the accuracy of the machine utilizing the matrix. On the other hand, increasing the number of nodes simultaneously increases the amount of workload, time and money spent on constructing the CAA matrix. This paper presents a number of experiments aimed at creating CAA matrices with different number of matrix nodes using the LaserTracer system. The relations between maximum permissible errors obtained on a machine using matrices with different densities of nodes are also discussed. Additionally, the authors attempt to tackle the question of determining the most optimal density of nodes with regards to the ratio of time spent on matrix creation and the effect on accuracy.