薄壁铜及铜合金高频焊焊缝接头的错位研究

分析了薄壁铜及铜合金高频焊接焊缝接头的错位及其产生的主要原因,研究了焊缝接头错位与焊接过程稳定性及焊缝强度的关系,提出了焊缝接头错位的预防和控制方法。     

温度荷载作用下含裂缝的沥青路面结构应力分析

应用有限元素法对含有裂缝的半刚性基层沥青混凝土路面在温度荷载作用下的应力状况进行了初步分析,得到不同参数情形下裂尖应力强度因子,研究结果对沥青路面结构设计具有一定的参考价值。     

对水泥稳定碎石基层设计与施工的再认识在铜黄高速公路上的应用

修建高质量的水泥稳定碎石基层,必须从原材料抓起,级配与水泥剂量是影响水泥稳定碎石裂缝的主要因素,推广使用骨架密实型级配与合理水泥剂量,可有效防止裂缝的出现,避免在高温以及低温时施工等措施,都可保证施工的顺利进行.     

基于本体论的城市构筑物三维描述

为了解决城市构筑物空间描述现有方法存在的空间目标划分和表达困难的问题,应用本体论的基本理论———部分-整体关系,分析了城市构筑物的描述层次和几何定义;从部分和整体两方面对空间实体的联系进行了分析,提出了一种基于本体论的城市构筑物三维描述框架,并用V isual C 语言和OpenGL Perform er图形软件包实现了原型系统.     

Finite Element Analysis for Multi-pass Equal Channel Angular Pressing

Equal channel angular pressing (ECAP) is an attractive process method to produce bulk ultra-fine grained materials. There are many experiment evidences showing that the nature of the microstructural evolution in multi-pass ECAP depends on process routes. Isothermal three dimensional FEM simulations for multi-pass ECAP were performed using DEFORM3D finite element code. The material model of 6061Al-T6 was employed. Flow nets, effective strain distribution in the workpiece and loads during multi-pass ECAP using different routes were analysed respectively. The simulations show process routes influence material flow and effective strain distribution in the workpiece obviously but have few influence on loads.     

THE STUDY ON THE CHANGES OF ZINC, COPPER, CALCIUM AND MAGNESIUM IN PLASMA AND ERYTHROCYTES DURING CARDIOPULMONARY BYPASS

Objective To study the changes and their influence factors involved of zinc, copper, calcium and magnesium in plasma and erythrocytes during cardiopulmonary hypass(CPB). Methods Zinc, copper, calcium and magnesium values in plasma and erythrocytes were measured by atomic absorption spectrophotometer during CPB. Results Zinc and copper levels in plasma were significantly elevated above preinduction level before perfusion, hut calcium and magnesium levels did not change significantly; zinc, copper and calcium levels in plasma were significantly below preoperation level during CPB, hut magnesium level in plasma was significantly increased above preoperation; zinc level in plasma was increased to preoperation level after CPB and began to decrease again at 8 hours after CPB,copper level in plasma was increased to preoperation level at 20 hours after CPB, calcium in plasma was increased significantly from beginning to 8 hours after CPB, magnesium level in plasma was decreased to preoperation level at 8 hours afterCPB. Concentration of zinc , copper, calcium and magnesium in erythrocytes did not change significantly. Conclusion During CPB, the changes of zinc, copper, calcium and magnesium had relation to hemodilution, operative wound, carrier protein, stress and component of priming Solution and cardioplegic solution, hut no relation to transferfrom plasma erythrocytes. The results indicate that it is beneficial to patient‘s recovery to supplement zinc, copper, calcium and magnesium properly by different ways during cardiac perioperation.     

梦圆青运 期许未来——大金龙绿色通勤助力首届青运会圆满闭幕

<正>10月27日下午,首届青运会闭幕式在福州海峡奥体中心综合馆举行。仪式运用绚丽的舞台效果、富含海峡及青春元素的精彩演出告别本届盛会,宣告"福之州,青之运"圆满收官。全场最大的亮点是星空告别环节。灯光熄灭后,观众们挥舞着手机、手电筒,把现场变成一片"星空"。这片美得震撼人心的"星空"代表着对首届青运会的依依惜别,也表达着人们对美好大自然的殷殷期许,再次呼应大赛"绿色、清新、环保"主题。     

基于关系数据库的抽象查询

抽象查询是数据库应用系统中的一种程序设计方法。该方法为数据库应用系统查询使用者提供了一个比较良好的、全面直观的数据聚集查询调配。模糊了使用者对数据库应用系统的专业性限制，并为用户掌握和了解数据内容、数据关联顺序起到了一个得力的助手作用。使用二叉树原理是建立数据库的抽象查询的数学模型依据，二叉树算法能够使应用系统开发人员建立直观的E-R关系数据结构，并为数据库的扩展奠定了可靠的关系基本数据模型，使抽象查询有一个较完整的基础数据。     

薄板点焊预压时接触压力的有限元分析

对薄板结构点焊预压阶段进行了弹塑性有限元分析，得到了在锥端和球端两种电极作用下工件-工件界面和电极一工件界面的接触压力分布及工件变形情况：计算结果表明，工件在焊点附近的局部变形符合圣维南原理，但在多焊点柔性大结构的分析中应考虑局部变形的累积效应。预压阶段的分析结果有助于确定后续瞬态多耦合场分析时的初始条件.     

基于WC粒子掺杂改性提高碳/铜复合材料综合性能研究

碳/铜复合材料广泛应用于轨道交通、机械制造及航空航天等领域,但由于界面间的天然不润湿性导致液相浸渍制备过程中容易形成气隙缺陷,影响复合材料的性能。将碳化钨(WC)粒子作为第三相引入传统碳/铜两相体系当中,研究掺杂改性对复合材料结构、元素、润湿性能的影响,并建立两相流有限元仿真模型,研究铜熔体在多孔碳基内部的微观渗流行为。结果表明,通过引入少量的WC粒子可以明显改善界面间的润湿性能,提高流场的均匀性。经计算,在基体中随机掺杂适量WC颗粒使碳/铜复合材料的气隙率减少3.11%,最大速度减少0.27 m/s,平均速度增加0.05 m/s。