Hybrid strain based three node flat triangular shell elements—II. Numerical investigation of nonlinear problems

In a companion paper [M. L. Liu and C. W. S. To, Comput. Struct. 54, 1031–1056 (1995)] theories and incremental formulation of nonlinear shell structures discretized by the finite element method are discussed. The updated Lagrangian formulation and the incremental Hellinger-Reissner variational principle are adopted. The independently assumed fields employed are the incremental displacements and incremental strains. Based on the theory and incremental formulation explicit element stiffness and mass matrices of three node flat triangular shell finite elements are derived. In the present paper the derived element matrices are applied to nine examples. The latter include static and dynamic response analysis of shell structures with geometrical, material, and geometrical and material nonlinearities. The formulation adopted and element matrices derived are found to be accurate, flexible and applicable to various types of shell structures with geometrical and material nonlinearities.     

圆盘式高速金属冷锯机锯切功率的实验研究

对１６００圆盘式高速金属冷锯机进行了锯切功率的实验研究。对某厂四种有代表性的产品，用不同的进锯速度，实测每种条件下的锯切功率变化，和最大瞬时锯切功率与平均锯切功率之比。并以实测数据为基础，得出每种产品以进锯速度为自变量的平均锯切功率回归公式。这些工作，不仅可以为这种冷锯机锯切功率的理论研究提供依据，还可直接为使用和设计这种冷锯机给出具体参考数据。     

温度,压力对漂移室气体增益的影响

研究了温度及气体压力对漂移室（工作于正比区）气体放大倍数的影响，温度和气体压力的变化范围分别是５￣４０℃及９０￣１０５ｋＰａ。用实验数据拟合得到了函数关系并测量了几种饱和度下函数中的参数值。     

建立河南油田“全天候”电网的探讨

按照建立“全天候”电网的要求,分析了油田电网大气过电压保护设计标准偏低,方案选型不合理;内部过电压保护不完善;线路及设备污闪严重;抗自然灾害能力差;以及通讯系统、运行管理、综合治理等方面的问题。提出了完善大气过电压保护;加强内部过电压保护等5项适应“全天候”电网的措施。     

加速SPICE进行三维电磁分析

互连结构的电磁分析越来越受到人们的重视.针对三维互连,A.E.Ruehli提出了部分元等效电路法.但该法生成的等效电路具有紧耦合性,用SPICE进行分析时稀疏矩阵技术已失去原先的优越性.本文采用广义残量法作为大型紧耦合线性方程组的求解工具以取代SPICE中的LU分解法,并辅以初值预估.实际计算表明,本文的方法提高了运算速度.广义残量法也可用于矩量法的方程求解中.     

羧酸酯稀土对聚氯乙烯的热老化稳定作用研究

用热烘法研究了羧酸酯稀土对聚氯乙烯的热老化稳定作用。利用紫外／可见光谱分析跟踪共轭双键在热老化过程中的变化，比较ＣＥＲＥＳ，有机锡及两者的复合稳定剂的热老化稳定性能，发现ＣＥＲＥＳ与有机锡的稳定性能相当，复合稳定剂具有协同效应。     

UL认证漫谈（六）

介绍了ＵＬ试验室和中国检测机构的ＴＰＴＤＰ合作计划。     

智能化红外焊缝检测仪的实时信号自相关分析

详细介绍了在改进红外焊缝检测仪的过程中实时信号的一种抗干扰方法－－自相关方法。重点离自相关方法的数学模型，软件框图及设计思想，并给出了实验结果。     

On social computing research collaboration patterns: a social network perspective

The field of social computing emerged more than ten years ago. During the last decade, researchers from a variety of disciplines have been closely collaborating to boost the growth of social computing research. This paper aims at identifying key researchers and institutions, and examining the collaboration patterns in the field. We employ co-authorship network analysis at different levels to study the bibliographic information of 6 543 publications in social computing from 1998 to 2011. This paper gives a snapshot of the current research in social computing and can provide an initial guidance to new researchers in social computing.     

基于USB电源的智能风扇控制技术

介绍基于计算机USB电源的智能风扇控制技术。