单位力法在运动学中的应用

本文从虚功原理导出了适合于运动学问题求解的单位力法，可以很方便地求得运动学系统中指定点，指定方位的速度和加速度。     

关于虚功法计算电场力的讨论

根据能量守恒和转换定律，讨论由虚功法求介质从平板电容器中移出时所受电场力解可能得到错误答案的原因。     

关于虚位移独立性的研究

从虚位移方程的基础解系出发探讨虚位移的独立性，并根据Четаев定义将其结果推广到高阶非完整系统。同时，根据对实位移的相应讨论，明确指出实位移是不相互独立的。     

变质量可控力学系统的广义Mac-Millan方程

本文利用Gauss 变分原理及加速度空间的广义虚位移关系把广义 Mac-Millan 方程推广到变质量可控力学系统,给出了相应方程的准坐标表述。在此基础上,根据 Nielsen 算子和 Euler 算子的关系得到了变质量可控力学系统的 Nielsen自然方程。最后分别证明了准坐标下变质量可控力学系统广义 Mac-Millan 方程和Appll 方程、Nielsen 自然方程与广义 Nielsen 方程的等价性。     

Aeroacoustics of musical instruments

Musical sound can be generated from numerical solutions obtained from simple physical models of wind-instruments. We call such synthesizers virtual instruments. Crude caricatures capture the global oscillation behaviour of original instruments, providing the musician with a means of expression comparable to that obtained when playing real instruments. Music is, however, produced by details of the flow which correspond to much smaller temporal and spatial scales than the control of the global oscillation. This suggests that one has to split the physical model into two distinct parts: a simple numerical oscillator followed by a complex sound production module, driven by the output of the first module. We illustrate the background of this idea by a discussion of the clarinet, the human voice, and the trombone.General invited lecture presented by A. Hirschberg at the 12th Italian Congress on Theoretical and Applied Mechanics AIMETA '95, Napoli, 3–6 October 1995.     

基于IrYdium Chemistry Lab的可视化教学设计——以“盐类的水解”为例

利用虚拟化学实验软件IrYdium Chemistry Lab为基本工具，探讨其在“盐类的水解”一节进行可视化教学设计的具体方法和教学应用价值。说明基于虚拟化学实验的可视化教学设计，能兼顾表达思维可视化过程和结果，有利于强化学生的学科理解能力。     

Partial absorption and “virtual” traps

The spatial probability distribution associated with diffusion and attenuation in partially absorbing media is studied. An equivalence is established between a system with free diffusion for x>0 and partial absorption for x<0, and a semi-infinite system (x>0) with a radiation boundary condition at x=0. By exploiting this equivalence, it is shown that the effect of a partially absorbing medium in the long-time limit is equivalent to that of a perfect, virtual trap whose size is smaller than the original absorbing medium. For short times, however, there is substantial penetration of diffusing particles into the absorber. The virtual trap approach is readily generalized to higher dimensions. This allows one to obtain the density profile of diffusing particles around a partially absorbing spherical trap. An unusual crossover between short-time penetration and long-time trapping occurs in two dimensions; the size of the virtual trap is exponentially small in the case of weak absorption, corresponding to an absorption time which is exponentially large.     

Electromechanical dynamics analysis and simulation on rollforming equipment with both sides variable cross-section

Electromechanical dynamics analysis and simulation on a rollforming equipment with both sides variable cross-section are discussed in this study.The system includes mechanical parts and electro-magnetism parts, and it is a strongly coupled electromechanical system.Based on a virtual work principle and given power,generalized forces of this system are obtained.By using Lagrange-Maxwell equations, a model of electromechanical dynamics is established.Differential equations of two-phase winding on d-q axis are obtained by Park transformation, which comes from three-phase winding equations on the A-B-C axis.This system is solved with the 4th order Runge-Kutta’ s method, and discrete solutions of all variables are obtained.Finally, by using Matlab language, the system is simulated.The results show that the proposed method works very well.     

基于3DSMAX和OpenGL的虚拟治疗仪的建模

放射治疗是目前临床医学中常用的方法,放疗过程的模拟可以从最大程度上减少放射治疗的失误及对病人和器官的损害.虚拟治疗仪的设计,是整个虚拟治疗的一部分,本文用3DS MAX进行治疗仪的组件建模,用VC++6.O结合0penGL编程实现治疗仪的组合,设置了其运动参数.将四元数表示用于治疗仪的旋转变换来实现三维对象的快速旋转.