On the corrosion fatigue crack initiation model and expression of metallic notched elements

In the present study, attempts are made to extend the application of the mechanical model for the fatigue crack initiation (FCI) and the FCI life formula of metallic notched elements in laboratory air to those in the corrosive environment. The test results and analysis of the corrosion FCI (CFCI) life of aluminum alloys and Ti---6A1---4V show that the expression of the CFCI life obtained by modifying the FCI life formula in laboratory air can give a good fit to the test results of the CFCI life. The salt water (3.5% NaCl) environment has no effects on the CFCI resistant coefficient compared with the FCI resistant coefficient in laboratory air. However, 3.5% NaCl environment greatly decreases the CFCI threshold of aluminum alloy, but has little effect on the CFCI threshold of Ti---6A1---4V. The loading frequency ranging from 1 Hz to 10 Hz has no appreciable effect on the CFCI life, and thus, the CFCI threshold of aluminum alloys investigated. Hence, the expression for the CFCI life of metallic notched elements proposed in this study is a better one, which reveals a correlation between the CFCI life and the governing parameters, such as, the geometry of the notched elements, the nominal stress range, the stress ratio, the tensile properties and the CFCI threshold. However, this new expression of the CFCI life needs to be verified by more test results.     

Control of peak sidelobe level in adaptive arrays

Adaptive beamforming techniques are now widely used to reject interference (jammer/clutter) signals in radar, communication, and sonar applications. In adaptive arrays using the sample matrix inversion (SMI) algorithm, inadequate estimation of the covariance matrix results in adaptive antenna patterns with high sidelobes and distorted mainbeams. In this paper, a method is proposed to precisely control the peak (rather than average) sidelobe level of adaptive array patterns. The proposed method is also generalized to adaptive array antennas with moderate bandwidth and large random amplitude and phase errors. Theoretical analysis and simulation results are provided to illustrate the performance of the method proposed     

严寒地区双层窗的防冷凝研究

本探讨了北方双层窗的严重的冷凝现象及其给室内环境带来的危害。并提出了防止双层窗冷凝的GM－I型和GM－Ⅱ型设计方案，并以大量实验数据为依据，证实了该所提方案的实际应用价值。     

一种基于三次样条函数求离子浓度的自动算法

本文提出了一种用三次样条函数模拟双次标准加入法测量方程，直接求解离子浓度的自动算法。比较了三咱不同边界条件下用要池数计算离子浓度的结果。造出节点区间两极端点的二阶导数为零时的三次样条函数为最佳模拟函数。并讨论了该方法在实际分析中误差的来源及消除办法。经对一系列文献数据的验算对比，表明本法完全可代替传统的迭代法和查图法，且能方便地设置在智能化的电位分析系统中。     

参数化图形库技术

本文论述了参数化图形库的实现原理，建立了以尺寸叠加算法为基础的参数化图形库开发工具，利用这种开发工具建立的图形数据可以由数据库管理，方便有效。     

“点对多点微波通信机助工程设计系统”的若干技术问题

本文介绍由天津大学电子工程系和天大无线电厂联合开发的“点对多点微波通信机助工程设计系统”。该系统技术方案先进,具有投资省、功能多、设计快、适应范围广、操作方便等一系列特点,是进行点对多点通信工程设计的现代化理想工具。     

A STEP-BASED CAD/CAPP INTEGRATION

ＡＳＴＥＰ－ＢＡＳＥＤＣＡＤＩＣＡＰＰＩＮＴＥＧＲＡＴＩＯＮＺｈｅｎｇＬｉａｎｙｕ；ＤｕＰｅｉＡＳＴＥＰ－ＢＡＳＥＤＣＡＤＩＣＡＰＰＩＮＴＥＧＲＡＴＩＯＮ￥ＺｈｅｎｇＬｉａｎｙｕ；ＤｕＰｅｉＡｂｓｔｒａｃｔＴｈｅｉｎｆｏｒｍａｔｉｏｎｉｎｔｅｇｒａｔ...     

DGPSL：A DISTRIBUTED GRAPHICS LIBRARY

ＤＧＰＳＬ：ＡＤＩＳＴＲＩＢＵＴＥＤＧＲＡＰＨＩＣＳＬＩＢＲＡＲＹＳｈｉＪｉａｏｙｉｎｇ；ＰａｎＺｈｉｇｅｎｇ；ＺｈｅｎｇＷｅｎｔｉｎｇＤＧＰＳＬ：ＡＤＩＳＴＲＩＢＵＴＥＤＧＲＡＰＨＩＣＳＬＩＢＲＡＲＹ￥ＳｈｉＪｉａｏｙｉｎｇ；ＰａｎＺｈｉｇｅｎｇ；...     

一个面向CAD／CAM的演绎数据库管理系统

演绎数据库管理系统ＤＥＤＢＭＳ是工程数据库管理系统ＥＤＢＭＳ／２中的一个子系统。本文着重介绍其产生式语言用户界面、工作流程及功能特点。ＤＥＤＢＭＳ系统的开发，使ＥＤＢＭＳ／２不仅具有工程数据据管理功能，而且具有数据演绎和知识处理能力，从而成为ＣＡＤ／ＣＡＭ系统集成化和智能化的有力支撑工具。     

新型实用布线算法──L─M算法

本文提出新型布线算法，集李氏迷宫法与线搜索法的长处为一体，以饱和带法进行动态排序，以线搜索法确定借孔位置，然后用李氏法进行单层布线，获得最佳路径，从而达到线型好，布通率高的效果。