麦克斯韦

One of the keys for understanding the Maxwell demon phenomenon is establishing a flux model.

通量模型的建立是理解麦克斯韦妖现象的关键问题。

Week 16 Self-induction, mutual induction, energy of magnetic field, simple introduction on Maxwell electromagnetic theory.

第16周自感，互感，磁场的能量；麦克斯韦电磁理论简介。

Week 2 Self-induction, mutual induction, energy of magnetic field,/displacement current, integral form of Maxwell equations.

第2周 自感互感磁场的能量；位移电流；麦克斯韦方程组的积分形式。

Based on the Maxwell Equation, theoretical formula of microwave permeability and permittivity of polycrystalline iron fibers are introduced.

基于麦克斯韦方程，给出了多晶铁纤维的微波磁导率和介电常数的理论公式。

Lame -Maxwell equations of equilibrium have important applications in photoelasticity.

拉密-麦克斯韦平衡方程在光测弹性力学中具有重要的作用。

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。

Using the finitedifference timedomain electromagnetic method and c language program in the matlab software,the spatial electromagnetic field distribution radiation of photoconductive dipole antenna is calculated and displayed on the computer in a pseudocolor graph.

研究了光电导天线产生太赫兹波的辐射特性，利用麦克斯韦方程及其边界条件，计算了近远场的电场强度；采用电磁波时域有限差分方法，在Matlab系统软件中，用C语言编写程序计算光电导偶极天线的辐射太赫兹波的空间电磁场分布，并在计算机上以伪彩色图形显示，这种电磁场的可视化结果为天线的设计和改进提供了直观的物理依据。

The on-line density measurement technology with microwave has been narrated as a key part. We has deduced relations between permittivity、the load Q-factor and resonant frequency. And the electromagnetic field for closed cavity 、open cavity has been analyzed. we also discuss the design of cavity that is used in experiment、means for how to stir electromagnetic wave and choice of diameter/length ratio for cavity.

接着重点说明了微波在线密度测量原理，基于麦克斯韦方程组深入推导了微扰情况下介电常数与谐振频率，有载品质因数的关系；分别讨论了封闭谐振腔和开孔谐振腔中的电磁场以及微扰方法中所使用的谐振腔的设计及设计中激励方式、腔长/半径的选择等若干关键问题。

From the Maxwell′s equation,the quasi static electromagnetic field equations in a perfect conductor have been deduced in this paper.The equations are used to analyze two eddy current field engineering problems,and good results are obtained.

本文从麦克斯韦方程出发，推导出良导体内的似稳电磁场方程，将导出的电磁场方程用于分析两个电磁工程实例，获得了两个工程问题的涡流场解析计算结果。

One of the major contributions of Maxwellian theory was that it set up an essential relation between the electromagnetic field and light in vacuum, and defined the speed of electromagnetic wave as the constant speed of light c , which implies a hypothesis that the rest mass of the photon should be zero exactly.

麦克斯韦电磁理论的一个重要贡献在于它将真空中的电磁场与光联系起来，并将电磁场的传播速度定义为真空的属性，即恒定的光速 c ，因而建立了电磁波与光之间的本质联系。

With Death guitarist Schuldiner adopting vocal duties, the band made a major impact on the scene.

随着死亡的吉他手Schuldiner接受主唱的职务，乐队在现实中树立了重要的影响。

But he could still end up breakfasting on Swiss-government issue muesli because all six are accused of nicking around 45 million pounds they should have paid to FIFA.

不过他最后仍有可能沦为瑞士政府&议事餐桌&上的一道早餐，因为这所有六个人都被指控把本应支付给国际足联的大约4500万英镑骗了个精光。