原理

Basing on the variation principle of solid-fluid coupled problem,on the situation of the tank being full filled,the essential method and principle have been found by using the numerical approximation of finite element method.

在罐车满载的情况下，根据固液耦合问题的广义变分原理，使用有限元的近似数值计算方法，找到解决满载罐车液固耦合振动问题的基本方法和原理，建立铁路罐车的固液耦合问题的动力学控制方程，并通过算例验证液体对罐车耦合振动的影响，得到在工程上所需要的分析结果。

It introduced fundamental functions of elastic mechnics, elastic FEM, principle of virtual displacement and the creation of structure equilibrum equation.

第二章 有限单元法原理部分，在该部分中概要介绍了弹性连续体的有限元方法，虚位移原理和结构平衡方程的建立。

3 Computation of virtual work principle and structural displacement : understand the content about the virtual work principle of deformable body and its application; skillfully master the calculation method of statically determinate structure displacement by loads; master the calculation method statically determinate structure displacement by temperature variation and support movement; know Reciprocal theorems .

虚功原理和结构位移计算：理解变形体虚功原理的内容及其应用，熟练掌握在荷载作用下静定结构位移的计算方法，掌握静定结构在温度变化，支座移动影响下位移的计算方法，了解互等定理。

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。

This paper introduces the development and principle, and present study situation of electrohydraulic proportional control system, and the work principle and every component of electrohydraulic proportional valve-controlled motor system of test platform are analyzed in detail, establishing the mathematics model of the valve-controlled motor system.

本文介绍了电液比例控制系统的发展、原理及目前的研究现状，对试验台的电液比例阀控马达速度控制系统的工作原理及各组成部件进行了详细的分析介绍，建立了阀控马达速度控制系统的数学模型。

This paper presents the work principle and the design of the high-speed water jet loom and the design process of the control system,including the dardware and the software,and how to protract the circuit principle fig and PCB.

本文主要介绍了高速喷水织布机的工作原理及设计要求，叙述了喷水织布机控制系统的设计过程，包括硬件电路和软件编程，以及用Protel DXP软件绘制电路原理图和PCB图的方法及步骤。

They reveal a new principle, namely the a priori principle of purposiveness of our power of judgment, and thereby offer new a priori grounds for beauty and biology within the framework of Kant's transcendental philosophy.

这两部份揭露了一个新的原理，即我们判断力的先天合目的性原理，藉此康德在其先验哲学的体系内部有了新的先天基础让美与生物学有了位置。

Under it's direction to natural science,human beings can broaden their outlooks.And only in this way,nature can be considered as a harmonious organic system.As a transcendental principle,the theory of purposiveness of Nature can be used with the principle of Mechanical Movement at the same time . In Section Three,the author highlights two points about the concept of End.

康德认为在它对自然科学的指导下，人类可以开阔视野，把自然界看成一个有机的协调系统，所以自然合目的性作为一条先验的原理可以在反思判断力中运用而与机械性原理毫无冲突。

Food microbiology covers the following topics: the distribution and zoology of pathogenic microorganism and the microbe that can cause putrescence of different foods, the theory and methods of restricting their growth and preserving food, their application in food fermentation, detected and identifiedmothods, the quality assure system and related technology, such as HACCP, hurdle technology and the standard developed by International Commission of Microbiological Specializations on Food .

课程简介：食品微生物学主要是讨论介绍各类食物中常发现的腐败与病原性微生物的分布与生态特征，及为限制其繁殖而形成的各种食品保藏方法及其原理；微生物在食品发酵中的应用及发酵原理；现代微生物检测和鉴定方法；讨论HACCP、栅栏技术及国际食品微生物标准委员会等制订的食品微生物标准等质量保证体系和方法。

Introduced in accordance with the principle of infrared detectors made of various types, mainly give a passive pyroelectric infrared alarm structure theory and application circuit.

介绍了根据红外线原理制成的各种类型的探测器，主要给出了一种被动型热释电红外报警器的结构原理及其应用电路。

I am accused of being overreligious," she said in her quiet, frank manner,"but that does not prevent me thinking the children very cruel who obstinately commit such suicide.""

客人们在卡罗利娜·埃凯家里，举止就文雅一些，因为卡罗利娜的母亲治家很严厉。

Designed by French fashion house Herm è s, this elegant uniform was manufactured in our home, Hong Kong, and was the first without a hat.

由著名品牌 Herm è s 设计，这件高贵的制服是香港本土制造，是我们第一套不配帽子的制服。