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21.
本文通过对压电量测系统等效电路图的逐步简化,得出矩形脉冲信号的漏电方程;并对系统在各种情况下的时间常数,漏电相对误差进行了计算,最后就系统在校准和现场测试中经常碰到的几种情况,进行了定量估算,从而解决了压电量测系统在使用中的一些具体问题。 相似文献
22.
概述了高压放大器的基本组成,以及采用高压稳压电源措施,提高高压放大器的性能,并简述了高压放大器输出级的工作原理,给出了过渡保护方法。 相似文献
23.
介绍了邯钢动力厂真空变压吸附制氧设备的工艺流程,从切换阀本体、电磁阀及仪表气源等方面分析和总结了真空风机入口压力低引起系统联锁停车故障原因,并介绍了相应的处理措施。 相似文献
24.
Seung-Hwan Kim Seung-Bok Choi Sung-Ryong Hong M.-S.Moon-Sik Han 《International Journal of Mechanical Sciences》2004,46(1):269-157
This paper presents vibration control of a flexible beam structure using a hybrid mount which consists of elastic rubber and piezoelectric stack actuator. After identifying stiffness and damping properties of the rubber and piezoelectric elements, a mechanical model of the hybrid mount is established. The mount model is then incorporated with the beam structure, and the governing equation of motion is obtained in a state space. A sliding mode controller is designed in order to actively attenuate the vibration of the beam structure subjected to high-frequency and small magnitude excitations. The controller is experimentally realized and measured control responses such as acceleration of the beam structure and force transmission through the hybrid mount are evaluated and presented in both frequency and time domains. 相似文献
25.
钟伟明 《石油化工设备技术》2002,23(2):64-66
广州分公司炼油厂重油催化裂化装置四机组轴流风机在 1998年 9月由于入口消音器故障引发重大事故 ,严重影响了装置生产。该文主要针对其损坏的原因、情况和修复方法作了探讨和论述 相似文献
26.
A numerical simulation model for random large amplitude vibration control of composite plate using piezoelectric material is presented. The H∞ control design is employed to suppress the large amplitude vibrations of composites plates under random loading. The numerical simulation model is developed and based on the finite element method. The finite element governing equation includes fully coupled structural and electrical nodal degrees of freedom, and consider the von Karman large amplitude vibration. The modal reduction method using the structural modes is adopted to reduce the finite element equations into a set of modal equations with fewer degrees of freedom. The modal equations are then employed for controller design and time domain simulation. In the simulations without control, the value of the linear mode to the nonlinear deflection is quantified; and the minimum number of linear modes needed for accurate model is obtained. In the simulations with control, it is shown that the truncated modes, which are neglected in the control design, deteriorate the controller performance. Generally, the vibration reduction level is not monotonically increasing with the size of the piezoelectric actuator. The optimal piezoelectric actuator size depends on the excitation level. For higher excitation level, optimal actuator size is larger. The H∞ controller based on the linear finite element formulation gives better vibration reduction for small amplitude vibration, but it still gives reasonable performance for large amplitude vibration provided that the piezoelectric actuator is big and powerful enough. 相似文献
27.
Sun Linzhi Luo Yi Zhang Yanan Sun Ping Qin Xinjie Gong ZhenbangPrecision Machinery Institute Shanghai University Shanghai China 《机械工程学报(英文版)》2002,15(4):303-307
An experimental bimorph piezoelectric element (PZT) actuator for small pipe robot is developed. The robot can move in φ20 mm pipe, and can carry a CCD camera for detecting cracks or fine holes on inner surface of pipe. The velocity of the robot can reach 17~22 mm/s for vertical pipe up/down, respectively. Moving principle and its performance characteristics are presented. 相似文献
28.
该文在总结国内外高效离心风机的设计经验基础上,掌握和利用已有的经验,遵循一系列离心风机优化准则,成功的完成了高效机车用牵引电机通风机的设计.性能样机经台架试验,比原风机的性能有较大幅度的提高,效率达到86%,在国内同样风机中效率是较高的. 相似文献
29.
Analytical solution for the axisymmetric plane strain electroelastic dynamics of a special non-homogeneous piezoelectric hollow cylinder 总被引:1,自引:0,他引:1
By virtue of the introduction of a dependent variable and the separation of variables technique, the axisymmetric plane strain electroelastic dynamic problem of a special non-homogeneous piezoelectric hollow cylinder is transformed to a Volterra integral equation of the second kind about a function with respect to time, which can be solved successfully by means of the interpolation method. Then the solutions of displacements, stresses, electric displacements and electric potential are obtained. The present method is suitable for a piezoelectric hollow cylinder with an arbitrary thickness subjected to arbitrary mechanical and electrical loads. Numerical results are finally presented. 相似文献
30.