容器冬季施焊焊接裂纹的控制措施探讨

文中从设备冬季现场组对焊接施工的实际出发,分析了低温环境下焊接裂纹产生的原因,并从钢的淬硬倾向、氢的有害影响、焊接拘束应力等方面采取控制措施,防止了焊接裂纹的产生,保证了低温环境下容器的焊接质量。     

石化企业110／35kV电力变压器微机继电保护

针对高压110kV电力系统,介绍了先进的继电保护装置在石油化工企业中的应用。根据110kv电力变压器微机型继电保护的基本原理,以国内某石化企业的110kV变电站为参考,对各种继电保护参数的设置进行了详细论述和计算整定。     

地震道的井约束混沌控制反演

本文先分析了地震道非线性反演中的混沌现象,然后从井出发,以非线性动力学不动点理论及混沌控制理论的基础,提出了井约束混沌控制反演方法。     

无支座约束结构在Excel中有限元求解的初步研究

针对水利工程设计中常遇到的无支座约束结构内力计算，以涵洞倒虹吸工程结构为背景，拟探索一种能够在设计中应用的方便快捷的计算方法。经过研究与对比分析，初步确定了用有限单元法原理作为基本理论依据，采用“单元生与死”的技术，以Microsoft Excel 2000作为载体，研究设计出了此类结构的计算模型，并结合此模型研制了一个通用的内力计算表格。给出实例的计算结果与理论值的对比分析曲线。证明了此方法的有效性。     

运用复合刚度方法对Z型构件支撑屋面系统的侧向约束力分析

复合刚度方法是一种可以预测Z型截面构件支撑的屋面系统侧向受力的方法。该方法将一系列Z型截面作为单自由度系统分析,并采用刚度公式计算系统中不同的构件对于抵抗侧向位移的贡献。从力学理论中推导出屋面系统所需的抗力。     

Deflection behaviour of plate girders loaded in shear at elevated temperatures

This paper presents a theoretical investigation about out-of-plane and in-plane deflection behaviour of plate girders loaded in shear at elevated temperatures at the pre- and post-buckling stages. Theoretical elastic analysis of plate out-of-plane deflection employs an approximate approach using a combination of classical plate theory and Galerkin’s method. Effects from initial out-of-plane imperfections have been addressed, with the considerations of various varying degrees of thermal restraint. These elastic analytical solutions are compared with experimental results and numerical predictions. In addition to an out-of-plane deflection investigation, a combination of shear strength theory for plate girders and energy method is adopted to describe the in-plane vertical deflection of plate girders. The advantages and implementations of these methods are also discussed.     

拟动力实验中位移误差的分析及抑制方法

本文对采用显式Ｎｅｗｍａｒｋ法的拟动力实验方法进行了分析，指出欠调和超调两种主要的系统误差对实验结果的影响，提出了采用人工阻尼抑制误差增长的方法，对于输入是ＥＬ－ＣＥＮＴＲＥ地震波的数值分析结果表明，这种方法具有很好的效果．     

Long-term effects of legislation and local promotion of child restraint use in motor vehicles in Sweden

The main objective is to study long-term effects of legislation and promotion of child-restraint use in motor vehicles. Subgoals are to describe the level of restraint use in cars and changes in mortality and morbidity patterns in regard to differences among age groups and geographical areas (morbidity). The study areas were; ‘The First Four’, ‘The Six Counties’, ‘The Rest of Sweden’, and ‘Sweden as a whole’, and the population were two age groups — 0–6 and 7–14 years. The incidence of restraint use comes from observations of car-seat-belt usage. Outcome evaluation was based on hospital-discharge data 1978–1996 and mortality statistics 1970–1996. The level of restraint use for children in the front seat was 97% in 1988 and was equal to 1995. Mortality data shows a decrease of 2.8% on an average per year, 76% over the study period. A significant change over time in the two intervention areas was shown (annual changes of −2.8 and −1.8%), but not in the rest of Sweden. The local authorities that started early with preventive programs, such as safety seat loan schemes and those having an organised safety-promotion program showed a much better improvement than the rest of Sweden. There is a need for appropriate information for local action on childhood injury prevention to accompany national legislation.     

基于PCL技术的定位系统概述

基于PCL技术的定位在电子战领域越来越受到重视。文中以表格形式列出国内外现有该系统的结构、性能，表述了目前可用的外辐射源和所采用的PCL等主流技术，着重阐述了直达波、地杂波抑制和微弱信号检测等系统实施的7个关键问题，最后讲述并分析了该系统的最新动态与发展趋势。     

一种新型固有应变法的焊接变形仿真

以T形焊接接头为算例,结合热弹塑性有限元法和映射应变分量法研究角焊缝角变形的产生机制,认为固有剪切应变才是产生角变形的主要根源,而不是传统思维认为的横向固有正应变.随后,以此观点为基础,对比分析了两种不同的加载方位对横向约束度、横向固有应变及残余角变形的影响.沿焊缝表面斜向加载更接近于实际测量值和热弹塑性模拟值,表明了此种加载方位的合理性,为更合理的利用固有应变法预测焊接残余变形提供了有益的参考.