Experimental investigation on the piezo-composite actuator with piezoelectric single-crystal layer

Studies on muscle mimicking actuators have increased in the last two decades due to the possibility of various applications for compact lightweight actuators including small unmanned aircrafts, missile, and biomimetic robots. Piezoelectric materials have been used in a variety of applications ranging from shape control of structure and active vibration control of structure to noise suppression due to compact size and good frequency response. Conventional polycrystal piezoelectric ceramic materials, however, have limited actuating strains and displacement, hindering their use in actuators for small aerospace vehicles. In this study, the design and fabrication method of an actuator with a piezoelectric single-crystal layer were investigated to increase the actuation strain and displacement. From a comparison of the performance of the LIPCA-C2 and LIPCA-S prototypes, it was found that the new LIPCA-S2, which has much higher coefficient of the unimorph actuator, can generate an actuating displacement more than twice that of LIPCA-C2.     

Effect of Gd doping on crystalline orientation,structural and electric properties of PZT thin films prepared by Sol-Gel methods

Gadolinium (Gd)-doped lead zirconium titanate (PGZT) thin films have been prepared by Sol-Gel methods to investigate the effects of Gd doping on crystalline orientation, structural and electric properties of lead zirconium titanate (PZT) films according to doping concentration from 0% to 5%. Conventional heat process and appropriate doping concentration, without introducing a single crystal seed layer, were used for obtaining (100)-oriented PGZT thin films with dense columnar structures. The maximum dielectric constant (1310.35 at 100 Hz) and the optimum ferroelectric properties were obtained for 2% Gd-doped film. 1% Gd-doped PZT film exhibited excellent piezoelectric properties.     

Modeling and Analytical Solution of Hybrid Thermopiezoelectric Micro Actuator and Performance Study Under Changing of Different Parameters

Micro actuators are an irreplaceable part of motion control in miniaturized systems and are intended to have a high range of deformation, high accuracy, large force, and quick response. In this article, an analytical model for a hybrid thermopiezoelectric micro actuator is developed in which a double lead-zirconnate-titanate piezoceramic (PZT) beam structure consisting of two arms with different lengths are used. Governing differential equation of motion and electrical field are derived and solved. Out of parametric studies it was observed that, under application of temperature and voltage gradients, the deflection of the actuator shows different trends depending on the geometry of the micro actuator and also type of PZT material.     

多层压电陶瓷降压变压器的环境测试研究

电压增益、输出功率、效率是表征压电变压器(MPT)工作性能的3个重要参数。使用为华公司提供的径向振动型多层压电陶瓷降压变压器,测量其基本电学性能;温度对导纳圆等阻抗特性的影响;温度对其基本电学性能的影响等。综合研究降压变压器的环境温度稳定性。结果表明:压电变压器环境稳定性良好,但长时间剧烈的环境变化会对其使用性能产生一定影响,高温环境对其影响比较大。     

烧结温度对0.9PbZr0.52Ti0.48O3-0.1NaNbO3压电陶瓷结构及电学性能的影响

采用传统固相烧结法制备了钠过量的0.9PbZr0.52Ti0.48O3-0.1NaNbO3(PZT-NN)压电陶瓷,研究了烧结温度对PZT-NN陶瓷晶体结构及其电学性能的影响。XRD结果表明,不同温度烧结的PZT-NN陶瓷均为单一钙钛矿结构,在1125~1150℃温区烧结时,陶瓷发生了由四方相向正交相的相变。随烧结温度进一步升高,压电常数d33、介电常数εr以及剩余极化强度Pr均呈递减趋势,烧结温度为1125℃的PZT-NN陶瓷具有较好的电学性能:d33=218pC/N,εr=851,tanδ=0.02。PZT-NN陶瓷的相对密度随烧结温度的升高而增大,在1150℃时达到95%,钠过量的NaNbO3加入使PZT陶瓷的致密化烧结温度降低了50~150℃。     

扇区水泥胶结成像测井仪换能器

压电换能器是扇区水泥胶结成像测井仪器CBMT(Cement Bond Mapping Tool)的核心部件,其性能优劣直接影响着仪器的测井效果。文章论述了压电换能器在扇区水泥胶结成像测井仪中的应用,介绍了压电换能器的工作原理,分析了其频率特性。总结了提高CBMT水泥胶结成像测井仪中极板换能器灵敏度的方法。     

三片式LCOS激光投影显示中复合散斑的抑制

研究了三片式硅基液晶(LCOS)激光投影显示中散斑的成因、类型及其光学统计特性,并分析了激光散斑大小的测量方法。在此基础上,选用旋转散射片来减少三片式LCOS激光投影系统中产生的复合散斑,并通过一系列的仿真和实验,使得该激光投影机对比度C降到了人眼可接受的范围4.2%。证明了旋转散射片的方法能有效减少复合散斑,具有光学结构简单、实施性强等优点。     

压电主动控制在减振和降噪中的应用

利用压电主动控制进行减振和降噪实验具有广阔的发展前景.该文设计了3个相关的方案:简支梁的减振、铝板的降噪和基座的减振.实验结果显示,对于单频信号减振和降噪的效果均可达90%,证明了通过压电主动控制来实现单频的减振和降噪的可行性和显著性.     

基于声表面波纸基微流器件研究

研制了压电基片上能实现样品前处理的纸基微流器件.在128°YX-LiNbO3基片上制作了1个叉指换能器和1个反射栅;亲水性纸用来制作微流器件的微通道,浸有指示剂滤纸作为微反应器,一同粘附于透明胶带上,并采用聚二甲基硅氧烷(PDMS)贴合于压电基片上.叉指换能器激发的声表面波驱动压电基片上的样品,使其输运到纸基微通道,并在纸基微反应器进行微流分析.在研制的纸基微流器件上实现了NO2-浓度的快速检测.     

基于小波分频的压电式人工中耳信号处理研究

基于一新型压电式人工中耳,提出利用小波分频方法对其信号进行处理,使该植入装置能模拟正常中耳的传递特性.首先,基于Bark频谱理论,利用小波分频技术将输入信号分为17个频带;再参考中耳传递特性,对每个频带的信号赋以相应的增益系数;最终,通过实验验证该方法的可行性.结果表明,该法可使压电叠堆的输出能较好地反应正常中耳的传递特性.