Decomposition of the Two Lowest Lamb modes in a Bonded Plate

Based on the expression of the dispersion equation of Lame waves in an adhesive two-layered plate pressented in our proevious paper [Chin,Phys,Lett,18(2001)1483],the two lowest Lamb modes,the symmetric mode S0 and the antisymmetric mode A0 are successfully decomposed in the low-frequency regime,Relations between the rigidity of the bond and the velocity of the two Lamb modes are found,which lay a foundation for the estimation of the bond rigidity of the adhesive plate.The influence of the variations of the bond rigidity in terms of the stiffness constants KN and KT of the spring model on the velocity of the two Lamb modes in discussed and numerically evaluated.numerical results indicate that the deterioration of the bond rigidity causes the phase velocity decrease for Lamb modes of the two lowest order,thus having a possibility for the evaluation of the bonding state of the adhesive plate by using ultrasonic wave velocity measurement.     

论珠心算教练师培训的价值取向

珠心算教练师国家职业标准的公布施行,对规范珠心算教学、强化对珠心算教练师培训管理具有重要的现实意义,这是各级珠算协会今后一个时期的一项新的工作任务。为此,如何正确定位和科学把握珠心算     

间断磁探针阵列诊断数据的振荡模式分析

托卡马克磁探针阵列通常是围绕等离子体均匀布置的完整环形系统。由于受到布置空间的限制，HL-2A装置的磁探针只能组成带空白区域的间断阵列。在分析了HL-lM极向磁场振荡——Mirnov振荡模式的基础上，探索了HL-2A磁探针阵列诊断应注意的问题。     

无电极电光电场传感器灵敏度提高的研究

从提高灵敏度角度出发,理论上分析了无电极电光电场传感器电极长度与灵敏度和带宽的关系.通过比较不同结构的传输函数,验证平衡检测方式的可行性,最后选取使用平衡检测的三端口结构作为实验器件结构,从而为器件制作的可行性方案从理论上作了验证.     

New Compacton-Like and Solitary Pattern-Like Solutions of （2＋1）-Dimensional Generalization of Modified KdV Equation

Recently some （1＋1）-dimensional nonlinear wave equations with linearly dispersive terms were shown to possess compacton-like and solitary pattern-like solutions. In this paper, with the aid of Maple, new solutions of （2＋1）- dimensional generalization of mKdV equation, which is of only linearly dispersive terms, are investigated using three new transformations. As a consequence, it is shown that this （2＋1）-dimensional equation also possesses new compacton-like solutions and solitary pattern-like solutions.     

加工中心本体故障模式的统计研究

本文对加工中心整机及机床本体的故障模式及其分布规律进行研究,分析了产生故障的原因,指出了提高加工中心可靠性的途径.研究表明加工中心机床本体故障率最高,刀库与机械手是其可靠性最薄弱的环节.     

Geodesic Acoustic Mode in Toroidally Axisymmetric Plasmas with Non-Circular Cross Sections

The geodesic acoustic mode （GAM）, first predicted by Winsor, Johnson and Dawson in an attempt to explain some experimentally observed low frequency oscillations in stellarators, is a special electrostatic fluid mode with low mode number and coupled with the so-called geodesic curvature of a toroidally confined plasma. The recent on this mode are due to the close relevance of the stabi- lization of drift turbulence by both the zonal flow and the GAM. Previously, the GAM was illustrated in very simple geometries,     

走出解答高考理论联系实际题目的误区

从1999年起，为了配合素质教育，高考物理理论联系实际以及高科技的题目明显增加，尤其是近两年高考，全国普遍实行3 x模式，这类题目更受命题者的青睐，考生由于受思维、方法、技巧、策略等方面的限制，在解答这类题目时经常陷入误区，现分析如下。     

关于《数据库原理》教学中数据仓库构建步骤的探讨

本作根据3年多的《数据库原理》的教学经验，在数据仓库知识的构建部分提出了六步构建方案，通过教学实验，学生容易理解，反响较好，下面就如何构建来进行展开。它的六个构建步骤分别是：概念模型设计，技术准备工作，逻辑模型设计，物理模型设计，数据仓库生成和数据仓库的运行与维护。并重点针对运行与维护在实际使用过程中考虑不周而导致的某些问题，通过仔细分析，提出了部分见解。