Oscillation of an elastic bar rigidly linked to a kinematically excited pendulum

The oscillation of a mechanical system consisting of an elastic bar rigidly linked at the middle to a kinematically excited pendulum is studied. A system of integro-differential equations with appropriate boundary and initial conditions for the deflections of the bar axis and the rotation angle of the pendulum is derived using the Hamilton-Ostrogradsky principle. Given kinematic excitation conditions, the rotation angle is found as a solution to an inhomogeneous Hill equation in the form of a double power series in the amplitude of kinematic excitation. It is shown that the oscillation of the bar is the linear superposition of three oscillations __________ Translated from Prikladnaya Mekhanika, Vol. 42, No. 10, pp. 107–115, October 2006.     

Fast MRI coil analysis based on 3-D electromagnetic and RF circuit co-simulation

To accelerate the analysis of a multi-element MRI coil, a two-way link is used between radiofrequency (RF) circuit and 3-D electromagnetic (EM) simulation tools. In this configuration, only one 3-D EM simulation is required to investigate the coil performance over a range of different tunings, saving considerable computation time. For the purpose of 3-D EM simulation, the coil feed networks and trim capacitors are substituted by 50 Ω ports. The entire coil was tuned in the RF circuit domain, and the near-field profiles of the electric and magnetic field components were then calculated, together with the specific energy absorption ratio (SAR) maps in the 3-D EM domain     

电工实验三层次教学探索与实践

分析了电工实验教学中存在的突出问题,提出三层次实验教学的新思路和实施方法,切实加强学生实验能力和创新能力的培养。     

以“三乡”文化为主题开发东阳旅游业

东阳旅游资源丰富,尤其是人文旅游资源,不但数量大, 而且品位档次高, 文化内涵深邃源远. 本文以 其主体———教育之乡、建筑之乡 、工艺美术之乡的“三乡”文化为主题, 根据东阳旅游资源开发的有利条 件,在旅游业发展战略、旅游开发的目标定位与开发思路、旅游产品与路线开发等方面, 对东阳旅游业的 开发进行探讨.     

基于ASP.NET的“三标一体”文件管理系统的实现

主要介绍了在“三标一体”(ISO9001:2000质量管理体系I、SO14001:1996环境管理体系和GB/T28001-2001职业健康安全管理体系)管理体系中,如何运用ASP.NET+SQLSERVER2000技术,实现对组织内部各类体系文件的高效管理,为组织通过认证和维护体系提供一套实用、科学、规范的应用软件.     

希望《水浒》三大疑案早日作出定论--记罗尔纲先生未了的心愿

我国老一辈的著名学者罗尔纲先生一向以对太平天国史的研究闻名于世。很多人都不知道,他对《水浒》一书的研究,比对太平天国史的研究起步更早,历史更长,用力更勤。直到去世,他对《水浒》三大疑案———主题、作者、原本———的破解工作仍未完成。因此,由后人来接棒,继续进行研究,破解三大疑案,整理出一部最真(没有伪造部分)、最善(内容比较成熟)、最美(文字已作加工)的《水浒传》来,传之后世,就成为罗老未了的心愿。     

大转矩三段弧鼓形齿式联轴器

大转矩三段弧鼓形齿式联轴器 ,一直以来国内都无法满足要求 ,费用昂贵 ,从现有掌握的技术和国内先进加工手段 ,我公司对该类联轴器进行开发和技术攻关 ,结果表明 ,它不仅能满足我公司需要 ,节约大量外汇 ,而且还可替代进口轧机配的国外联轴器 ,占领国内市场。     

A penalty-equilibrating hybrid stress 3-D element

This paper presents a theory about penalty-equilibrating(PEQ) hybrid element of three dimensions (3-D), and generates a model for the PEQ hybrid stress 3-D element. By the PEQ approach, the false stress is avoided and the precision in calculation is raised to a large extent under the mesh distortion condition without another additional degree of freedom. In the results of numerical examples, the present element is compared with the 8-node hexahedron element and the optimized hybrid element, and it is proved that our conclusion is correct. In addition, the penalty-equilibrating hybrid 3-D element is taken as a trial to calculate problems of square plate bending and incompressibility. The results obtained are satisfactory.     

熔锥平面型三光纤耦合特性分析

以线性耦合波方程为基础，分析了具有不同耦合强度的平面型三光纤耦合系统的模场特性和功率耦合特性，并与常规的平面型三光纤耦合系统的耦合特性作了比较，给出的耦合器谱响应实验结果与理论结果较为一致。     

电子束对LY12硬铝的损伤效应

对LY12硬铝受到电子束辐照时产生的热激波及材料的损伤破坏效应进行了理论计算,将计算值同实验结果进行比较,二者基本上是一致的。在研究中等能量沉积产生材料的破坏效应时,应适当考虑材料的熔化过程,所用的状态方程是GRAY三相状态方程,而在研究材料的损伤破坏时,我们修正了计及损伤效应的Bodner-Partom本构模型。