Iterative procedure for solution of sylvester generalized matrix equation

An iteration procedure for solving Sylvester generalized matrix equation is proposed in this paper. The sufficient conditions of stability of the iteration procedure for solving this equation are obtained. Translated from Kibernetika i Sistemnyi Analiz, No. 3, pp. 183–186, May–June, 2000.     

Further remarks for the matrix type-B codes

Different philosophies lie behind the detecting and correcting error patterns in a real communication channel. The sceptic points in choosing an efficient code, specifically the matrix type-B code, were pointed out in Refs. 1 and 2.Some more points are shown here. As a result the matrix type-B code is found to be a best choice. Some more theoretical aspects for this code are also given. These are useful for the realization and testing of an encoding-decoding algorithm with IC's used in a unique way for its implementation.     

FC-AE-1553与MIL-STD-1553协议转换方案的设计

为了实现FC-AE-1553和MIL-STD- 1553两种总线网络之间信息单元的准确传输,分析了当前航电系统的应用现状,描述了FC-AE-1553协议在总线应用方面的性能优势,提出了两种协议之间的转换方案,实现了两种信息单元格式之间的转换.在FC-AE-1553帧与MIL-STD-1553字相互映射关系的基础上,对协议转换方案进行了总体分析,并按照子功能进行了模块的划分.针对各个子模块,依据其运行机理给出了详细的设计流程.仿真分析结果表明,协议转换方案具有良好实时性能,具有很强的适应性.     

通用自动测试系统的软件设计与实现

讨论了自动测试系统的框架结构、基本功能,介绍了基于测试参数的通用自动测试系统的软件设计及各功能模块的实现。采用开放式结构及层次模型的软件设计,使用面向对象编程语言C#设计一个通用的测试管理平台、使用图形化编程语言LabVIEW完成基于测试参数的测试程序设计。将不同的测试功能模块封装成相应的TPS,通过测试管理平台配置相应的测试库及测试参数就可实现对不同测试对象的自动测试。该软件的设计方法提高测试程序的可移植性和可维护性,同时增强了测试平台的通用性。自动测试系统不仅提高了测试效率,而且经过重复的测试,验证了测试结果的准确性。     

大转动平面梁有限元分析的共旋坐标法

虽然大转动平面梁单元已有很多,但其中许多太复杂,缺乏计算效率,值得改进。采用共旋坐标法准确的首次导出了平面梁单元发生大转动小应变时的非对称单元切线刚度矩阵,利用这一非对称的单元切线刚度矩阵由Newton-Raphson迭代法编制了一个FORTRAN程序NPFSAP,并获得了大转动梁、方形和圆形框架的高精度数值解,表明了这种非线性单元列式的正确性和非线性求解过程的收敛性,非对称单元切线刚度矩阵值得推介。     

济钢烧结厂节能降耗的探索与实践

鉴于我国目前能源比较紧缺的状况,如何降低能源消耗及实现能源的循环利用,是各行业的共同努力方向。济钢烧结厂近年来从工艺技术和工艺改造等方面着手,不断挖掘降低工序能耗的潜力,经过不懈的努力,取得了比较明显的效果。     

锻造零件缺陷分析

介绍了四种典型锻造缺陷案例并进行了详尽的追述，主要从锻造过程中金属流动和冶金缺陷的重新分布的角度对锻造缺陷产生原因作了比较全面的解析，提出了解决这些问题比较成熟的经验和方法。     

基于网络的远程监测和故障诊断系统的数据库系统

随着信息技术和网络化向各个行业的延伸,实时监测已经成为机械设备监测的一种需要。而实时数据如何存取,采集后的这些历史数据如何为以后的故障诊断服务,在企业中如何来组织这些数据,是我们所要思考和解决的问题。所提出的基于网络的远程监测和故障诊断系统的数据库系统,正是基于上述的考虑,介绍了三个层次的数据库系统:企业监测站、企业监测中心和远程故障诊断中心。解决了实时数据的存取,历史数据的压缩,企业信息的管理等问题。整个库系统使用UML建模,对数据库系统进行了细致的分析和构造。     

建设工程招标代理过程中应注意的一些问题

结合目前我国招投标的实际情况提出招标代理过程中出现的一些问题及改进措施。     

On the reinitialization procedure in a narrow‐band locally refined level set method for interfacial flows

A local level set algorithm for simulating interfacial flows described by the two‐dimensional incompressible Navier–Stokes equations is presented. The governing equations are solved using a finite‐difference discretization on a Cartesian grid and a second‐order approximate projection method. The level set transport and reinitialization equations are solved in a narrow band around the interface using an adaptive refined grid, which is reconstructed every time step and refined using a simple uniform cell‐splitting operation within the band. Instabilities at the border of the narrow band are avoided by smoothing the level set function in the outer part of the band. The influence of different PDE‐based reinitialization strategies on the accuracy of the results is investigated. The ability of the proposed method to accurately compute interfacial flows is discussed using different tests, namely the advection of a circle of fluid in two different time‐reversed vortex flows, the advection of Zalesak's rotating disk, the propagation of small‐amplitude gravity and capillary waves at the interface between two superposed viscous fluids in deep water, and a classical test of Rayleigh–Taylor instability with and without surface tension effects. The interface location error and area loss for some of the results obtained are compared with those of a recent particle level set method. Copyright © 2005 John Wiley & Sons, Ltd.