大功率的

The welding of end ring of alternating current machine and the conducting bar is the key technology for manufacturing of asynchronous traction motor with high power. China South Locomotive and Rolling Stock Industry Corporation had taken this significative study as a key project for the manufacturing of alternating current machine. According to the welding of end ring of alternating current machine, the welding of copper and copper alloy is described in this paper. Results obtained in this study are as follows. 1.By the comparison of oxyacetylene gas brazing, induction brazing and resistance brazing, it was found that high-quality welding joint could be obtained by induction brazing, which also had the highest efficiency.

交流电机端环与导条的焊接是大功率异步牵引电动机制造的一项关键技术，开展其焊接工艺研究具有重要的意义，中国南车电机公司将此课题作为解决交流电机制造的一个重点项目，本文结合交流电机转子端环焊接的课题，对铜及其合金的焊接进行了研究，主要研究结论如下： 1、通过氧乙炔火焰钎焊、感应钎焊、电阻钎焊等焊接方法的对比试验发现感应钎焊可获得优质的焊接接头，且感应钎焊的焊接效率也是最高的。

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 survey uncovered where these disgusting noices are come from : the hooting lawn mowers in the summer,the cries in the evening parties in plats,the shouting neighbours,a variety of vehicles,especially for the lorries crossing the still villages,the planes and helicopters flying overhead,the powerful radios taken to the public with the largest voices.

这个调查揭示了我们不喜欢的大量的噪间的来源：夏天呜呜作响的割草机，公寓楼里深夜聚会的喧哗声，大声吵闹的邻居，各式各样的车辆，特别是穿越寂静的村庄的集装箱卡车，从头顶飞过的飞机和直升机，被带到公共场所、音量开到最大的大功率收音机。

The method of CFD numerical simulation is employed to replace experimental investigation. Hence, STAR-CD of the commercial software is used to simulate the outer flow field and heat transfer performance of integrated heat sink with heat pipes cooled by airflow. It is found that simulated results agree with experimental results well, which indicates that simulation method is reasonable and reliable. Further, simulated computations for different fin thickness, fin pitches and air velocities are performed to analyze their effects on heat transfer performance of heat sink. Finally, a new optimized structure of integrated heat sink with heat pipes is provided to meet future demands for cooling CPU and its heat transfer is also evaluated. For multi-heat source and higher dissipation power of electronic devices, the integrated heat sink with heat pipes attatched fins stagged in different positions of channels is presented and its flow and temperature fields are also simulated to enhance heat transfer. As a conclusion, all mentioned above are useful for the design of heat sink with excellent efficiency of heat dissipation and further research.

应用商业软件Star-CD对CPU集成热管散热器的外部流场和传热特性进行了数值模拟，将数值模拟结果和试验结果对比，验证了所提出的数值计算方法是可靠和可行的；利用此数值模拟方法对CPU集成热管散热器在不同散热翅片间距、厚度和气流速度下散热器的流动与传热性能进行了数值计算，分析了这些参数的变化对散热器传热性能的影响；针对未来CPU冷却的要求，确定了与最优气体流速匹配的最佳翅片间距、厚度的CPU集成热管散热器的新结构；利用试验评测了根据数值模拟提供的新结构开发出的新CPU集成热管散热器的传热性能；最后在场协同强化传热的理论的基础上，对CPU集成热管散热器的散热翅片错位排列来强化散热器的散热，满足未来大功率、多热源的电子元件的散热，为今后进一步优化散热器提供了依据。

In this thesis, Based on the advantages of diode-pumped solid-state laser in Chapter 1, the development of diode-pumped solid-state laser is introduced. The trends of DPSSL are pointed out, the wide application fields ,as well as the bright market future of high power DPSSL are also summarized. In the Chapter 2 , all kinds of solid-state laser gain materials are introduced in detail. In the Chapter 3 , the theory on the mode-matching of the pump beam and the cavity mode is analyzed in detail based on the basic theory and work principle of LD-pumped all-solid-state laser.

本论文第一章从二极管泵浦固体激光器的优势出发，介绍了二极管泵浦固体激光器的发展，指出了DPSSL的发展方向，概括介绍了大功率DPSSL的诸多应用领域和广阔的市场前景；第二章对固体激光增益材料作了详细的介绍；第三章基于LD泵浦固体激光器的基本理论和工作原理，从理论上详细分析了LD端面泵浦激光器中泵浦光与腔模的匹配问题。

The complete wind turbine speed control firstly proposed here also improves the tracking effect of wind turbine rotating speed to variable wind speed. Wind turbine rotating speed synchronized power observer compensates the power ripple of wind turbine resulted in inverter dead time. A low pass filter used at the output of MPPT controller smoothes the speed reference, which makes the rotating speed of wind turbine more stable.

本文首次提出的变转速扰动的MPPT控制提高了风车最大功率点追踪的快速性和稳定性，风车完全转速控制提高了风车转速对变动风速的跟踪效果，转速同步风车功率观测法消除了逆变器死区所造成的风车功率波动的影响，带有低通滤波器的MPPT控制器使得风车的转速更加趋于平稳。

It is reassuring that many intermational broadcasters have taken the opportunity to re-equip with high-power broadcast transmitters that are not only capable of high efficiency PDM operation, but are also capable of providing conventional DSB operation, compatible AM and full SSB, in the next five years, many more will have re-equipped in preparation for SSB broadcasting.

可以确信，许多国际广播电台已经获得了用不仅具有高效率的 PDM（或 PSM，在 ABB的情况下）方式工作，而且也具有传统的双边带、兼容的调幅和全单边带工作能力的大功率广播发射机换装的机会，在下一个五年内将有更多的单边带广播作换装的装备。

Well-known, the sources of energy of the computer room uses up the element is many sided, include the each hardware establishment that initial stage purchases not only, wait like server, UPS, air conditioning, distribution, illume, still include to use phone daily, safeguard, and the enlarge look of relevant equipment.

维护，以及相关设备的扩容等。因此，设备的能耗。效率成为用户选择产品时考虑的主要因素，作为保障数据中心安全运行的UPS设备也不例外。面对大功率。大体积。低效率的传统UPS产品，用户不再只是&一生叹息&，而是把目光投到高效率。低能耗的节能环保型产品上。那么，满足什么样的条件才是&绿色&UPS产品呢？通常高效率。

According to the clear water experiment, aeration performance of the new equipment is good with high total oxygen transfer coefficient and oxygen utilization ratio.

曝气设备的动力效率在叶轮转速为120rpm～150rpm时取得最大值，此时氧利用率和充氧能力也具有较高值。

The environmental stability of that world - including its crushing pressures and icy darkness - means that some of its most famous inhabitants have survived for eons as evolutionary throwbacks, their bodies undergoing little change.

稳定的海底环境─包括能把人压扁的压力和冰冷的黑暗─意谓海底某些最知名的栖居生物已以演化返祖的样态活了万世，形体几无变化。