振

To change the exciter eccentric weight, get a different amplitude.

改变激振器偏心重，可获得不同振幅。

Xie Zhendong of reporter of exercitation of report from our correspondent reports integratedly: After Microsoft of Yahoo excuse oneself from quotes, microsoft ever expressed to will take all necessary steps.

本报讯 实习记者叶振东综合报道：雅虎婉拒微软报价后，微软曾表示将采取一切必要手段。

In which, the equation of motion of the loaded beam is derived analytically by means of the expansion theorem (or the mode superposition method) incorporated with the natural frequencies and the mode shapes of the bare beam (i.e., the beam carrying nothing).

其中，负载梁的运动方程式乃藉由膨胀原理结合裸梁的自然频率与振态来推导。

Structured character and expansivity of the system and independability between substructure elements have been improved by effective encapsulation of the isolators, and object-oriented analysis idea and system solving strategy have been developed as a result.

通过对隔振器的有效封装，增加了系统的结构化特性和可扩展性以及子结构单元之间的独立性，从而形成了面向对象的系统分析方法和系统求解策略。

A new discrete reaching law is presented to improve the reaching process of discrete exponential reaching law.The discrete-time variable structure control system designed by this reaching law can not only weaken the chattering and control the system state approach to zero diminishingly,but also keep the basic property of quasi-sliding mode which can cross the switching surface step by step.This method improves the reaching process and enhances the control quality of the control system.

为了改善离散指数趋近律的趋近过程，提出了一种新的趋近律，利用该趋近律设计的变结构控制器，不仅能够大幅度削弱抖振，使系统运动最终趋于原点不存在稳态振荡，而且能使系统的准滑动模态保持步步穿越切换面的基本属性，有效地改善了趋近过程，提高了控制品质。

Based on a series of signal process and noise source identification techniques, especially the major noise source identification methods, such as expurgation method, sound intensity analysis, spectrum analysis vibro-acoustic correlation analysis and so on, the pass-by noise control of SC7080A and SC6360B are studied in detail. By the roadway and dais experiments, the major noise and radiating parts are identified and some economical controlling methods are made. For the SC7080A, to control the emissing noise from the intake and shell vibration of air cleaner, a intake muffler is installed between the air cleaner and intake valve. Based on the theory of Helmholtz resonator, One three-parallel-connected resonant silencer is designed and trial-manufactured. For the SC6360B, the attenuation performance of exhaust muffler in high frequency region is improved. To reduce the vibration noise of shell part, the structure of oil sump tank, exhaust manifold shield and exhaust manifold shield are analyzed and improved. At the same time, some measures, such as sound absorption, sound insulation, are taken to reduce the noise of engine surface emissivity and a sound shield is designed.

本文首先综述了目前国内外汽车加速噪声控制的现状、主要方法和技术措施，在此基础上，结合SC7080A和SC6350B汽车的车外加速噪声水平及现状，综合运用分别运行法、声强法、频谱分析法、声振相干函数法等现代噪声源识别方法，对SC7080A和SC6360B汽车进行了准确详细的车外加速噪声源识别并提出了经济可行的控制方案，针对SC7080A，主要在空气滤清器和进气阀门之间的进气管道上加装进气消声器，抑制空气滤清器壳体表面和进气口两处的噪声辐射，根据Helmholtz共振腔原理设计了三腔并联旁支型共振消声器，并进行了工程化设计和试制；针对SC6360B，主要改善了排气消声器在高频段的消声性能，对罩壳类零件进行了结构改进，降低了其表面噪声的辐射，并对发动机舱进行了吸声、隔声处理，设计了发动机隔声罩。

The operating principle and the key manufacture technique of pre-stressed sensors and vibrating string extensometer have been approached.

对预应力传感器和振弦式钢筋计的工作原理和研制关键技术作了充分讨论。

The method of multiple scales was used to solve the Duffing equation, the solutions were used to analyze qualitatively the effect of boundary conditions, ratio of damp, external excitation, and ratio of inner radius to outer radius on the second-harmonic resonance of an annular thin plate.

用多尺度方法求此振动控制方程的3次超谐共振解和1/3亚谐共振解，并且定性地探讨边界条件、内外半径比、激振力和阻尼对环形薄圆板在这两种次谐共振下的动态响应。

The simulation results show that the amplifer with this configuration can obtain higher extractive efficiency and higher beam quality.

比较了不同的放大器输出特性，理论表明基于偏振方式的两级放大可获得较高的提取效率和光束质量。

By reason of the dipole directivity of particle velocity sensor and also the acoustic intensity averagor, and its being able to realize the electronic rotation, coherent interferences can be effectively suppressed by skillful use of its zero point and extremal point.

振速传感器和平均声强器具有偶极子指向性，并且该指向性可实现电子旋转。巧妙利用偶极子指向性的零点和极值点，可有效地抑制声场中的相干干扰。

However, as the name（read－only memory）implies, CD disks cannot be written onorchanged in any way.

然而，正如其名字所指出的那样，CD盘不能写，也不能用任何方式改变其内容。

Galvanizes steel pallet is mainly export which suits standard packing of European Union, the North America. galvanizes steel pallet is suitable to heavy rack. Pallet surface can design plate type, corrugated and the gap form, satisfies the different requirements.

镀锌钢托盘多用于出口，替代木托盘，免薰蒸，符合欧盟、北美各国对出口货物包装材料的法令要求；喷涂钢托盘适用于重载上货架之用，托盘表面根据需要制作成平板状、波纹状及间隔形式，满足不同的使用要求。