一种机械结构结合面动力学参数识别方法

机械结构结合面刚度和阻尼的确定是对结构进行动态分析和优化设计的关键问题之一。本文提出一种结合面动力学参数识别方法。该方法通过实测结构少量几个点上的振型和传递函数确定结合面参数。它不要求预先建立结构各部件的解析模型,也不需要实测整个结构完整的动态信息,因此适用于复杂结构结合面动力学参数的识别。文章阐明了结合面参数的识别原理,并讨论了如何消除实验误差对识别结果的影响。用本文方法识别了一台钻床的结合面参数,得到了令人满意的结果。     

左联合谱的一个刻划及其应用

In this paper we characterize the left joint spectrum of an n-tuple T =(T1,... ,Tn) of dominant bounded linear operators on a complex Hilbert space H and the unital C^*-algebra C^*(T) generated by T1,… , Tn and I; moreover, we give an application of this characterization.     

群体多目标决策联合有效解类的不变凸充分条件

对于群体多目标决策问题，文[1]引进它的联合有效解类的概念，并给出这类解的最优性必要条件，在对于问题的目标函数和约束函数附加凸性的条件下，文[2]又给出了联合有效解类的最优性充分条件，本文进一步在目标函数和约束函数具不变凸和不变广义 凸的情况下，分别给出了联合有效解类的若干最优性充分条件。     

利用联合付里叶变换谱干涉法测量透镜焦距

本文提出了采用联合付里叶变换频谱干涉法测量透镜焦距的方法。输入面上两个分布完全相同的图像经光学付里叶变换在频谱面上得到二者付里叶变换频谱的干涉条纹，通过测量干涉条纹的间距即可得到透镜的焦距。该方法装置简单、操作调整方便；易于采用实时空间光调制器、ＣＣＤ及微机实现快速自动测量，且具有较高的精度。文中进行了原理分析和实验验证。     

THE EIGENVALUE PROBLEM EQUIVALENT TO MULTIVARIATE POLYNOMIAL SYSTEM

In this paper, the authors proved that finding all solutions of a given multivariate polynomial system is equivalent to solving a relative joint eigenvalue problem(Theorem 1) and in some cases one can find all solutions of the given system from the eigenvalues and vectors of one matrix or matrix pencil (Theorem 2). Especially the situation that the ideal generated by the given system is 0-dimensional is discussed.     

A Practical Application of Ultrasonic Thermal Stress Monitoring in Continuous Welded Rails

A methodology designed to monitor thermally induced loads on continuous welded rails (CWR) is presented. The technique is based on the use of sub-surface longitudinal ultrasonic waves (l.c.r. waves) and, by means of a daily data elaboration, allows to obtain the value of the neutral temperature of the rail as a function of time. From such information an estimation of longitudinal stresses, to be used as a reference, can be derived. The methodology here presented has undergone a 2 years testing period, through the instrumentation of about 3 km of railway track. All acquired data have been remotely processed in a single control station.     

Effects of threshold on single-target detection by using modified amplitude-modulated joint transform correlator

Effects of threshold value on detection performance of the modified amplitude-modulated joint transform correlator are quantitatively studied using computer simulation. Fingerprint and human face images are used as test scenes in the presence of noise and a contrast difference. Simulation results demonstrate that this correlator improves detection performance for both types of image used, but moreso for human face images. Optimal detection of low-contrast human face images obscured by strong noise can be obtained by selecting an appropriate threshold value.     

The joint value-distribution of the Riemann zeta function and Hurwitz zeta functions

In this paper, we investigate the joint value-distribution for the Riemann zeta function and Hurwitz zeta function attached with a transcendental real parameter. Especially, we establish the joint universality theorem for these two zeta functions. Published in Lietuvos Matematikos Rinkinys, Vol. 47, No. 1, pp. 39–57, January–March, 2007.     

芯片封装焊球连接疲劳寿命预测分析--能量法和有效应变法之比较

研究了目前常用的两种芯片封装焊球连接的寿命预测方法一能量法和有效应变法。对焊球连接的材料本构关系进行了对比分析，并利用FORTRAN语言编制了相应的材料本构模型子程序，将其与有限元仿真工具ANSYS耦合，实现了将焊球连接的材料本构模型用户子程序导入到ANSYS的材料库。在此基础上模拟了三维芯片叠层球栅阵列尺寸封装的焊球结构，在热循环条件下(-40～ 125℃的工作状态，并分别利用能量法和有效应变法对焊球连接的寿命预测进行了比较分析，最后对两种方法作出了评价。     

与两个更新过程有关的某些联合分布

本文讨论的两个时偶问题涉及来一个泊松过程与一个更新过程穿越时间和更新数的联合分布．利用向量马氏过程方法得到了这些联合分布的变换，给出了一个与分布均值有关量的数值结果．