虚

Virtual displacement principle of the analysis statics was used to establish static-equilibrium equations, which was used in calculating driving forces and torques when the mechanism was at some static-equilibrium state.

采用分析静力学的虚位移原理建立静力平衡方程，并用该方程计算了机构处于某种静力平衡状态下的平衡驱动力及力矩。

Based on the virtual displacement principle of finite element method, a weak variation of GAO-YONG turbulence equations is put forward. The subroutine of the element and the integrated finite element code are generated by the finite element program generator successfully.

基于有限元方法中的虚位移原理，写出了不可压流Gao-Yong湍流方程组弱形式的微分方程表达式，利用有限元程序自动生成系统得到了全部有限元计算程序。

The mathematical model of coal-bed methane seepage is established considering slipped effect, giving the weak form of the differential equation based on the principle of virtual displacement, hereby writing FEPG program. Using FEPG system's all the source program of the finite element which considers the mathematical model of coal-bed methane seepage of slip effect the numerical solution is sought.

建立考虑滑脱效应的煤层气渗流数学模型，给出了基于虚位移原理的微分方程的弱形式，据此编写了FEPG程序，利用FEPG系统生成了考虑滑脱效应的煤层气渗流数学模型有限元问题的全部Fortran源程序，并进行了数值求解。

In this topic, the dynamic analysis methods for piezoelectric vibrator are studied systematically based on the theoretical model, FEM numerical experimentation and FEM governing equation for given compound-mode vibrator, and some valuable conclusions are obtained. The main work accomplished is summarized as follows: 1.Elaborate the main modeling methods for piezoelectric vibrator and the significance and necessity to study the dynamic characteristics of piezoelectric vibrator which emphasize the urgency of this paper. 2.Take the bending deformation induced by piezoelectric ceramic as example, the energy transfer mechanism of electric energy to mechanical energy are analyzed; the motion and force transfer mechanism are analyzed for the longitudinal-bending vibrator. 3.Based on mode assumption and Hamilton principle, the coupling model of piezoelectric vibrator of linear USM is built; moreover, the equivalent circuit model is obtained and a coupling equation represents the relation between electric parameters and mechanical parameters is derived which provides foundation to match the vibrator and driving circuit. 4.Combine the constitutive equation of piezoelectric ceramic with elastic-dynamical equation, geometric equation in force field and the Maxwell equation in electric field and the corresponding boundary condition equation, the FEM control equation for piezoelectric vibrator of USM to solve dynamic electro-mechanical coupling field is established by employing the principle of virtual displacement. The equation lays the foundation to study the non-linear constitutive equation of piezoelectric ceramic driven by high-power. 5.Define the dynamic indexes of characteristic of vibrator and carry out variable parameters simulation by calculating the model parameters and the electric characteristics of vibrator are simulated according to the equivalent circuit model. By numerical experimentation, the working mode of vibration of vibrator and the shock excitation results of the working frequency band which provides the mode frequency to realize bimodal are analyzed. Detailed calculation of the electro-mechanical coupling field parameters is made by programming the FEM control equation.

本课题从理论模型、有限元数值试验、有限元控制模型等方面以复合振动模式振子为例对超声电机压电振子的动力学特性及其分析方法进行了全面系统地研究，得出了许多有价值的结论，主要概括如下： 1、阐述了目前针对超声电机压电振子的主要建模方法，对压电振子动态特性的研究意义和必要性进行了论述，突出了本文研究内容的迫切性； 2、以压电陶瓷诱发弹性体发生弯曲变形为例，分析了压电陶瓷通过诱发应变来实现机电能量转换的机理；对基于纵弯模式的压电振子的运动及动力传递机理进行了分析； 3、基于模态假定，利用分析动力学的Hamilton原理，建立了面向直线超声电机压电振子的机电耦合动力学模型，并据此建立了压电振子的等效电路模型，导出了电参量与动力学特性参量的耦合方程，为压电振子与驱动电路的匹配提供了依据； 4、从压电陶瓷的本构方程出发，综合力场的弹性动力学方程、几何方程、电场的麦克斯韦方程以及相应的边界条件方程，采用虚位移原理，建立了压电振子动态问题机电耦合场求解的有限元控制方程，为研究其大功率驱动下的非线性本构模型奠定了基础； 5、界定压电振子的动力学特性指标，对压电振子的机电耦合动力学模型参数进行计算及变参数仿真；依据等效电路模型，对压电振子的电学特性进行了仿真分析；通过有限元数值实验，对压电振子工作模态附近的模态振型及工作频率附近的频段进行了激振效果分析，找出了实现模态简并的激振频率；利用有限元控制方程，通过编程计算，对压电振子的力电耦合场参数进行了详细计算，得出了一些有价值的结论。

However, we also need the print operation to be virtualprinting a Query should print the Query_base object to which the Query points.

我们希望用户可以用标准输出操作符打印 Query 对象，但是，也需要打印操作是虚函数——打印 Query 对象应打印 Query 对象指向的 Query_base 对象。

The projet is about the properties of electronic mesoscopic transport. We focus on the properties of compplex part of ac conductance in mesoscopic systems , and on the origins of its physics.

本项目是关于介观输运的研究，重点放在交流输运，并关注交流电导虚部的物理效应和物理根源。

Based on the concept of the non-proportional damping which may be divided into the proportional part for dissipation of energy and the nonproportional part for transformation of energy, a new modal superposition pseudo-force method is presented if the approximate decoupling method is not suitable. In this method the coupled modal equations are solved by iteration in which the coupling terms are treated as pseudo-force and set to the right side of the equations.

在不能进行近似解耦分析时，基于非比例阻尼可分为耗散能量的比例部分和转换能量的非比例部分这种概念，建立了一种拟力实模态叠加法，即把正则化的耦合模态方程中代表非比例阻尼部分的耦合项作为虚力，放到方程的右端，再运用迭代法求解。

Complex permittivity includes abundant information, since its real part is the dielectric constant, and the imaginary part is proportional to conductivity.

复介电常数包含了丰富的信息，其实部即为介电率，虚部与导电率成比例；并且介电常数与很多生理参数有关，例如温度、含水量、血量、血氧浓度等。

Used in china as a strengthening tonic during prostration, for impotence, and for diabetes due to

中医用于补虚，增强阳气，和"因内热引起的糖尿病"

Perhaps it is time for an introduction. I am Commander Ameer of the Protectorate - also your only hope of resolving the infestation of both void creature and Ethereum in this area.

也许现在是时候介绍一下自己了，我是保护者同盟的指挥官——埃米尔，也是你解决这个地区虚空生物和虚灵议会问题的唯一希望。

The split between the two groups can hardly be papered over.

这两个团体间的分歧难以掩饰。

This approach not only encourages a greater number of responses, but minimizes the likelihood of stale groupthink.

这种做法不仅鼓励了更多的反应，而且减少跟风的可能性。