Adaptive Lagrange finite element methods for high precision vibrations and piezoelectric acoustic wave computations in SMT structures and plates with nano interfaces

This paper discusses the validity of (adaptive) Lagrange generalized plain finite element method (FEM) and plate element method for accurate analysis of acoustic waves in multi-layered piezoelectric structures with tiny interfaces between metal electrodes and surface mounted piezoelectric substrates. We have come to conclusion that the quantitative relationships between the acoustic and electric fields in a piezoelectric structure can be accurately determined through the proposed finite element methods. The higher-order Lagrange FEM proposed for dynamic piezoelectric computation is proved to be very accurate (prescribed relative error 0.02% - 0.04% ) and a great improvement in convergence accuracy over the higher order Mindlin plate element method for piezoelectric structural analysis due to the assumptions and corrections in the plate theories.The converged lagrange finite element methods are compared with the plate element methods and the computedresults are in good agreement with available exact and experimental data. The adaptive Lagrange finite elementmethods and a new FEA computer program developed for macro- and micro-scale analyses are reviewed, and recently extended with great potential to high-precision nano-scale analysis in this paper and the similarities between piezoelectric and seismic wave propagations in layered structures and plates are stressed.     

切换天线发射的低截获率通信信号物理层安全传输

为了提高通信信号在无线传输过程中的物理层安全性,提出一种低截获率物理层安全通信信号. 发射机根据接收机发送的训练符号估计信道,并随机选取信道质量较好的天线加权发射信号. 各天线的权系数由天线的信道信息和通信双方约定使用的扩频序列决定. 由于发射天线的快速切换,发射信号是一种与发射天线信道信息和扩频序列相关的空间扩频信号. 期望接收机可采用与普通扩频信号接收机相同的方法解调接收信号,而窃听接收机由于信道的快速切换无法正常解调接收信号. 仿真结果表明,相比于参考方法发射信号,该文提出的信号不仅具有相同的物理层防窃听能力,而且还具有防侦测和一定的抗干扰能力,是一种更好的基于多天线发射的物理层安全通信信号.     

更安全更高效的新型核燃料

美国珀杜大学核工程师开发出了一种先进的核燃料，与常规燃料相比，其使用寿命更长，燃烧效率更高，每年可节省数百万美元。研究人员还创建了一个数学模型来进一步开发这一技术。     

中国人HLA-Ⅲ的遗传多态性

从1983年起,武汉同济医科大学中澳友谊补体实验室率先对中国人的补体成分(C4A、C4B、Bf、C2)的遗传多态现象进行了探测,确证我国人补体具有自己的遗传背景。《中国人HLA-Ⅲ的遗传多态性》是这方面的一篇综述。     

肺吸虫病的研究概况

温州医学院寄生虫学教研组积极贯彻党的卫生方针,重视山区人民健康,20多年来曾先后到浙南、浙西、浙东及上海等地调查研究肺吸虫病。1979年省委将此病列为浙江五大寄生虫病之一,要求在全省进行全面摸底,掌握流行范围和规律,并开展防治工作。1980年我组分别到奉化、丽水、龙泉、青田、文成、舟山等海拔在300～800米的山区,及宁波、温州、杭州等动物园,普查大批     

计算机UPI心理分析系统

本文提出了利用计算机进行ＵＰＩ心理分析系统设计的思想,着重讨论了系统的功能结构及ＵＰＩ数据库的结构设计,并对系统进行了实现。该系统的进一步研制开发对ＵＰＩ的应用推广有广泛的意义     

基础提高,滑移对多层房屋地震反应影响分析

应用分布参数法对基础提高、滑移对一地基土－多层房屋相互作用体系地震反应的影响作了实详细的分析，此外、对基础提高与滑移之间的相互影响了作了讨论。     

酵母菌Y—216SOD的提纯及其性质研究

用筛选的高产ＳＯＤ酵母Ｙ－２１６进行发酵培养，分离提纯出ＳＯＤ，并对其性质进行了初步的研究。确定了酵培养后的ＳＯＤ提取过程；甲苯破壁法裂解酵母Ｙ－２１６得ＳＯＤ粗提液，并通过ＤＥＡＥ－纤维素－３２柱层及超滤等方法，得纯化的超氧化物歧化酶，此酶部分等电点为４．５、最大紫外光吸收波长为２６０ｎｍ，耐热性较好，Ｍｎ６２＋可能是其金属辅基。     

Application of Structural Equation Modeling to Evaluate Service Quality of Sportswear Retailing

Structural Equation Modeling （SEM） used widely in sociology, economics and psychology is adopted. Based on data obtained from marketing research, and using statistical analysis software SPSSll. 0 and LISRELS. 7, Theory of Five Dimensions of service quality is proved to be suitable in sportswear retailing in China. It analyzes the relationship among five dimensions and puts them in order of importance as to service quality in sportswear retailing. Advices are given for sportswear retail companies to improve their .Service quality and enhance customer loyalty.     

基于多惩罚因子优化VMD的滚动轴承故障特征提取方法

针对变分模态分解(variational mode decomposition, VMD)在提取滚动轴承故障特征时预先设置多惩罚因子具有不确定性的问题,结合灰狼优化(grey wolf optimization, GWO)算法提出一种基于多惩罚因子优化VMD的滚动轴承故障特征提取方法。首先利用GWO算法实现VMD的多惩罚因子自适应优化,再利用优化得到的参数将滚动轴承的振动信号分解为多个本征模态函数(intrinsic mode function, IMF),最后对各个IMF分量作包络解调提取滚动轴承的故障频率特征。研究结果表明,在优化VMD参数时,该方法相对其他方法优化效率有了明显提高,并且提取滚动轴承故障特征效果显著,得到特征频率幅值为其他方法的2～4倍,证明了该方法的有效性和优越性。