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The small dipole aperture antenna provides a normal way for THz radiation, for which the Drude-Lorentz theory provides method to calculate the Terahertz waves from photoconductor.

但是传统的Drude-Lorentz方法只是适用于小孔径(孔径，这里指的是偏置电压两个电极之间的距离)光导天线。

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。

Four-hole plate provides the strongest torsion fixation and quincunx shaped nail provides the strongest bending fixation.

4种内固定器中四孔钢板抗轴向扭转性能最好，梅花钉的三点弯曲刚度最强，对于胫骨骨折，Ender钉和矩形钉可以提供较好的稳定作用。

The community information system of town provides these services: community estate manage, net service, service for life, residenter information service and system manage. It also provides town society link system, registered permanent residence, planned parenthood and sanitation service by collaboration with other information systems.

小城镇社区信息系统提供的主要功能有社区建筑设施管理，生活服务，网络服务，居民信息管理以及系统管理，并通过与其他小城镇信息系统数据交互，实现了小城镇社会联动系统；提供户籍管理、计划生育管理以及卫生防疫管理等Web服务；实现了小城镇范围内的信息资源共享。

Easy Invoice provides Product Sales, Services and Professional Invoice format, Quotations and Packing-Lists, Sales History Reports, Inventory Control, Bar Code Scan, shows Product Photos and Customer's Photos, generates Sales Journal, Gross Profit Report and various Sales Analysis Reports, provides Customer Pricing,% or dollar amount Discounts at Line and Total levels, space for ample Notes at line, at total levels, and Option to send Invoice by e-mail.

容易发票提供产品销售，服务及专业发票格式，报价和包装清单，销售记录，报告，库存控制，条码扫描，显示产品的照片和客户的照片，生成销售日报，毛利润报告和各种销售分析报告，提供顾客定价，％或金额折扣路线和总水平，空间充裕的笔记，路线，在总的水平，并选择发送发票的电子邮件。

This thesis not only provides quantitative reference to the government management of social security, but also provides many helpful advices to the self-rule of the community.

本文既为政府管理社会治安提供了量化依据，同时也为社区自治提供了参考。

Through to pumps with the mechanical seal practical application and the theoretical analysis, proposed the mechanical seal actual seal effect not only with the mechanical seal own performance related, the condition which with other spare parts also which provides the condition as well as the seal servosystem provides to have the important relations, therefore pumps the unit product when the design, must for the mechanical seal use provide a good external condition.

通过对泵的机械密封实际应用和理论分析，提出了机械密封的实际密封效果不仅与机械密封本身的业绩有关的条件与其他零件也提供了条件以及印章伺服系统提供有重要关系，因此，泵的单位产品的设计时，必须对机械密封使用提供了一个良好的外部

The bark of certain species provides cork for flooring, soundproofing, and wine-stoppers, while the bark of other species provides tannin for leather-tanning, or compounds for medicines.

某一种类的树皮为地板，隔音板和酒瓶塞提供软木材料，而其他种类的树皮则为皮制品或者是药物的化合物提供单宁酸

All the atomic shells for the examined atoms are shown and the """"""""reasonable"""""""" electron numbers are given. Especially for atomic subshell and shell structure of transition elements are correctly predicated. This theory provides uniform and objective criterion for shell structure of isolated atom, and the intrinsic and theoretical basis for the shell structure given by other methods. This theory provides a kind of new method for describing the atomic shell structure.

该理论可以揭示原子的全部壳层结构，产生基本合理的电子数，尤其是正确的预示了原子的亚壳层结构和过渡元素的壳层结构；依据该理论所确定的原子内禀壳层结构为孤立原子的壳层结构提供了统一的客观标准，为其它方法所确定的壳层结构提供了内在的理论依据；原子内禀壳层结构理论为度量孤立原子中处于束缚态下电子排布的壳层结构，提供了清晰的物理图像，为描述原子的壳层结构提供了一种新方法和新理论。

The abundant superannuation fund provides the solid foundation for the countryside old-age insurance system, provides the safeguard for the countryside senior citizen's basic life.

充裕的养老基金为农村养老保险制度提供坚实的基础，为农村老年人的基本生活提供保障。

We are forbidden from giving money to these shoeless, skinny children, as this will perpetuate begging.

向光着脚，骨瘦如柴的孩子施舍是不可以的，因为要招来无休无止的乞讨。

It would be hard not to fall victim to some sharpeyed policeman.

要想不被某个目光锐利的警察抓到，谈何容易。