直流偏置对PZT微传感器的谐振频率的影响

在直流偏置电压对PZT压电微悬臂梁谐振频率的影响研究中,建立了理论方程,并通过激光干涉测试实验对所建方程进行了验证。理论方程和实验均表明:直流偏置电压对PZT微悬臂梁的谐振基频的影响是二阶函数。在直流偏置电场小于1×107 V/m时,直流偏置电压和谐振基频存在线性变化区。此结论可以用于改善谐振式PZT微悬臂梁传感器的信号检测系统,即利用扫描直流偏置电压取代频谱分析。     

硅基压电多层膜悬臂梁的偏转模型和优化设计

利用压电多层膜悬臂梁的形变曲率半径,导出了简洁的压电悬臂梁型微执行器的偏转模型.采用此模型,对硅基PZT压电悬臂梁型微执行器进行了模拟和分析.分析获得了各层薄膜结构参数与微执行器偏转位移的关系.根据此分析结果,进一步优化了压电悬臂梁型微执行器的设计,并给出了优化的方法.     

复合式压电振动能量收集器的研究

为解决无线传感器网络和便携式电子产品的自供能问题,研究了基于电磁耦合的压电悬臂梁式振动能量收集器.理论分析表明,通过增加压电悬臂梁的所受外力,可以按平方关系提高其产生的发电量.即采用PZT4压电元件及铍青铜作为金属基板,以固定于基板末端的永磁铁作为质量块制作了基于电磁耦合的悬臂梁式压电振动能量收集器.实验表明,压电悬臂梁附加永磁铁后其最大输出电压增加了222％,压电悬臂梁在磁场强度分别为0T与1T的作用力下,电压值的增幅分别为0.38％和2.12％.     

钟形陀螺微纳振幅曲面电容检测方法研究

钟形陀螺采用压电激励实现四波腹振动,通过检测振子边缘振幅以获取输入角速率。在其量程内的振子边缘振幅为120 nm左右,为实现对微纳振幅检测,将钟形陀螺振子边缘设计成曲面电容结构;采用有限元方法,对曲面电容结构进行仿真;在仿真结果基础上对微电容进行检测。结果表明:在极板面积为9π/4mm2、厚度为0.1mm、电极最小间距30μm时,钟形陀螺曲面电容结构可等效为平板电容器,固有容值为2 pF级别;可敏感120 nm的微纳振幅,容值变化为0.01 pF级别;曲面电容检测方法能够实现钟形陀螺微纳振幅检测。     

埋入混凝土中PZT声场指向性和声能研究

将PZT作为声源埋入混凝土中构成的混凝土压电机敏模块具有超声检测功能。对埋入该模块中的PZT圆片模态分析发现,在各阶振动模态下PZT声辐射面存在分布不同的振幅极大值区域。基于混凝土压电机敏模块的声场指向性和声能实验表明:将PZT声辐射面等效为振幅相等的单一点声源的叠加,忽略振动模态对声场指向性影响,使得PZT圆片的声场指向性随频率变化规律偏离实际较大,而且在相同频率下声场指向性理论结果比实验结果发散;在各阶固有频率激励下,PZT圆片的声场指向性集中,但在一阶固有频率下声能最高,更适用于超声检测。     

基于微悬臂梁传感器的微弱风力检测系统设计

针对现有技术对微弱风力检测困难的问题,搭建基于微悬臂梁传感技术的微弱风力检测系统并实现微弱风力检测.传感器平台使用光纤耦合激光器作为光源,对微悬臂梁自由端进行照射.由微弱风力导致的微梁自由端的微小位移经过光杠杆原理放大,通过四象限探测器感光表面上的光斑相对位置实现对微弱风力的检测.利用编写的LabVIEW程序进行数据采集控制,并实时显示微悬臂梁偏转位移曲线.实验结果表明:微悬臂梁的偏转位移和风力具有较好的线性关系,系统3倍噪声对应的风力约为1.5×10-4N,风力检测结果的平均标准差为6.7 ×10-9N,实验数据具有较高重复性.     

PT种子层对微力传感器性能的影响

为了提高微牛顿量级微力传感器的灵敏度,比较了有PT种子层和无PT种子层的PZT压电薄膜对微力传感器性能的影响。运用Sol-Gel(溶胶-凝胶)法制作了PZT和PT/PZT/PT薄膜,采用X射线衍射技术表征了PZT和PT/PZT/PT两种薄膜的成相特征,用半导体参数测试仪测试了PZT和PT/PZT/PT两种薄膜的漏电流。结果表明,在同为600℃退火温度下,两种薄膜均具有钙钛矿结构,而且PT/PZT/PT薄膜沿(100)晶向强烈取向。当外加电压增加时,PZT薄膜的漏电流基本保持不变;PT/PZT/PT薄膜的漏电流变化在1nA左右。最后应用MEMS工艺分别制作了基于PZT,PT/PZT/PT压电薄膜微悬臂梁结构的微力传感器,并在静态和准静态下对微力传感器的传感特性进行了测试。测试结果表明,添加PT种子层对微悬臂梁的弹性系数基本没有影响,但微悬臂梁的灵敏度显著增加。     

基于压电自供电的采煤机状态无线监测装置

考虑到压电自供电装置中压电振子的几何参数直接影响其共振频率,从而影响压电自供电装置的发电量,因此需要根据环境激励频率设定最佳的压电振子的几何参数,本文对基于压电自供电的采煤机状态无线监测装置进行研究,通过理论分析、仿真以及实验方法对对不同悬臂梁结构在不同外界激励作用下的发电量进行研究。研究结果表明：悬臂梁自由端质量块质量以及悬臂梁长度越大,悬臂梁压电结构的固有频率越低;随着悬臂梁厚度的增加,悬臂梁压电结构的固有频率逐渐增大。以此为依据对采煤机不同监测位置的装置选取最佳匹配的压电结构几何参数,并通过采煤机工作状态监测实验验证了本文研究的压电自供电无线监测装置的可行性。     

一种简单便携的存储介质信息检测及备份装置研究

随着信息时代的飞速发展,数据信息在生活中的作用越来越显重要,数据恢复在社会生活中的应用越来越广,这便需要对存储介质的信息进行必要的检测和备份。虽然一些常见的软件可以通过PC端实现检测和备份功能,但也就是针对常见USB设备和一些专业性比较强的硬盘,不方便备份且不易携带,因此能提供一种兼容各种存储介质,并且方便使用、易于携带且不依赖于电脑就能实现检测和备份的设备非常重要。本文阐述了一种简单便携的存储介质信息检测及备份装置的研究设计．．     

压电微悬臂梁气体传感器静态弯曲模型的研究

压电微悬臂梁是一种灵敏度高、尺寸小的生化传感器.分子或原子在压电微悬臂梁功能化表面的吸附会引起悬臂梁的静态弯曲,通过静态变形可以得到微悬臂梁的表面应力.将表面应力引起的微悬臂梁中性层位置的变化引入建模过程,并与能量法相结合,建立了压电微悬臂梁在单分子层吸附稳定后的静态弯曲理论模型.结果发现在相同吸附表面积和吸附量条件下...     

Finite element analysis of a IBM suspension integrated with a PZT microactuator

This paper presents a piezoelectric-based microactuator concept that could provide an economical and easily integrated option for dual stage actuation used in hard disk drives (HDDs). A simple cantilever beam integrated with the PZT actuator was simulated first in order to testify the driving mechanics of the new design. A modern suspension (IBM Deskstar DTLA-307015) integrated with the developed PZT actuator was then simulated by finite element method (FEM). Theoretical dynamic and electrostatic analyses were performed to investigated the resonant frequency and displacement sensitivity. Good dynamic characteristics were obtained. Further simulation was done based on the optimized structure of the actuator/suspension assembly and results show that >1 μm tip stroke can be obtained while the driving voltage is only 20 V. A 10 V is sufficient to get >1 μm tip stroke if double layer PZT actuator is used.     

A comparative analyze of fundamental noise in cantilever sensors based on lateral and longitudinal displacement: case of thermal infrared detectors

The performance of novel cantilever-based sensors approaches the limit posed by thermo-mechanical fluctuations, which is the currently accepted fundamental detection barrier for micro- and nanomechanical sensors. At the same time, the sensitivity of a high-level measurement techniques used for readout of the cantilever displacement nears the value of 10^?14 m/Hz^½. However, the thermo-mechanical noise of some cantilever sensors based on bimaterial structures is considerably higher than imposed by the fundamental limit. Moreover, the signal-to-noise ratio of some sensors based on contemporary MEMS technologies falls behind the characteristics of older types of mechanical sensors, fabricated using macroscopic production technologies. To investigate the cause of this situation, we perform a comparative analysis of the performance limits for two classes of cantilever sensors: the bimaterial cantilevers where the output signal is the transversal (lateral) displacement of the cantilever tip and the simple cantilever sensors where the signal is the longitudinal displacement along the cantilever axis. As a starting point of our analysis we established a correspondence between the parameters of a bimaterial cantilever and the simple cantilever. In a general case these two structures are not directly comparable, since the deformation of the bimaterial cantilever depends on 14 variables, while the longitudinal elongation of the simple cantilever depends on seven parameters only. However, under certain conditions analyzed in this paper a partial correspondence between the parameters of these two structures can be established. Our analysis shows that in certain applications a cantilever with longitudinal elongation has potentially better performance than the corresponding bimaterial element.     

Design, fabrication, and characterization of a submicroelectromechanical resonator with monolithically integrated CMOS readout circuit

In this paper, we report on the main aspects of the design, fabrication, and performance of a microelectromechanical system constituted by a mechanical submicrometer scale resonator (cantilever) and the readout circuitry used for monitoring its oscillation through the detection of the capacitive current. The CMOS circuitry is monolithically integrated with the mechanical resonator by a technology that allows the combination of standard CMOS processes and novel nanofabrication methods. The integrated system constitutes an example of a submicroelectromechanical system to be used as a cantilever-based mass sensor with both a high sensitivity and a high spatial resolution (on the order of 10/sup -18/ g and 300 nm, respectively). Experimental results on the electrical characterization of the resonance curve of the cantilever through the integrated CMOS readout circuit are shown.     

用于痕量胺类同系物检测的谐振式微悬臂梁传感器

采用化学修饰法,将酸性羧基基团嫁接于高比表面的积的SBA- 15介孔材料中,然后将该功能化介孔材料负载于集成谐振式微悬臂梁表面,制得一种高性能的挥发性胺类同系物传感器.胺类分子的吸附将导致质量型微悬臂梁传感器谐振频率的下降,传感器检测下限可达ppb量级.对一系列胺类同系物的检测结果表明,胺类分子在羧基功能化介孔表面的吸...     

PZT微驱动器磁头的动特性研究

采用摄动法对描述超薄气体润滑理论的修正雷诺方程进行处理,建立了气体润滑的静动态方程,求解得到磁头气膜的无量纲刚度系数和阻尼系数,并讨论了磁头线速度对空气膜刚度系数和阻尼系数的影响.采用的磁头模型是一种PZT微驱动器磁头,其主体部分飞高为20 nm,读写头处飞高可达5 nm.模拟结果表明,磁头末端下降15 nm后,其动态特性和稳定性明显提高;磁头线速度在8.0 m/s～11.2 m/s变化时,气膜刚度系数线性增加,阻尼系数却线性减小.     

Fabrication and characterization of 3-Dimensional MOS transistor tip integrated micro cantilever

We fabricate and characterize a three-dimensional (3-D) MOS (metal–oxide–semiconductor) transistor tip integrated micro cantilever to measure the surface properties. The 3-D MOS transistor tip is fabricated on the front side end of the cantilever, and the cantilever itself works as a tip. These features make the device possible to investigate hard-detecting parts such as the deep trenches and the sidewalls of the structure. The MOS transistor tip has other advantages such as the high operation speed, the high sensitivity, and the reduction of the required equipments like the lock-in-amplifier. The MOS transistor tip is fabricated three-dimensionally, utilizing the lateral diffusion and the anisotropic wet etching with TMAH solution, since the etch rate of {211} plane is much higher than those of {100} or {111} planes. The gate area is formed by self-aligned technique, using crystallographic dependant wet etching. The well-known convex corner compensation pattern is used for the gate length control during the tip fabrication process. The characteristics of the fabricated device are measured with respect to the various electric signals and the results show the well-established detection properties.     

基于MS3110的微小电容读取电路设计

MS3110具有良好的微电容测量性能,可以满足电容法在气/固两相流测量中的应用。提供一种基于通用电容读取芯片MS3110的微小电容读取电路,并对MS3110的可编程参数设置做详细介绍。电路设计中使用89S52单片机对MS3110芯片进行编程控制和数据读取,最终实现对静态电容和动态电容的测量,并通过串口传输至上位机实时显示。     

Determination of exposure to engineered carbon nanoparticles using a self-sensing piezoresistive silicon cantilever sensor

A novel MEMS-based cantilever sensor with slender geometry is designed and fabricated to be implemented for determining personal exposure to carbon engineered nanoparticles (NPs). The function principle of the sensor is detecting the cumulative mass of NPs deposited on the cantilever surface as a shift in its resonant frequency. A self-sensing method with an integrated full Wheatstone bridge on the cantilever as a piezoresistive strain gauge is introduced for signal readout replacing optical sensing method. For trapping NPs to the cantilever surface, an electrostatic field is used. The calculated equivalent mass-induced resonant frequency shift due to NPs sampling is measured to be 11.78?±?0.01?ng. The proposed sensor exhibits a mass sensitivity of 8.33?Hz/ng, a quality factor of 1,230.68?±?78.67, and a temperature coefficient of the resonant frequency (TC _f ) of ?28.6?ppm/°C. These results and analysis indicate that miniaturized sensors based on self-sensing piezoresistive microcantilever can offer the performance to fulfill the requirements of real-time monitoring of NPs-exposed personnel.     

Modeling and analysis of experimental atomic force microscope images of hard colloidal particles

The fundamentals of atomic force microscopy (AFM) of hard colloidal particles are discussed. The idea of image modeling and deconvolution with the known AFM cantilever tip shape is described as well as a method for AFM tip calibration with the use of spherical colloidal particles. The algorithms and programs for AFM image modeling and experimental data analysis are presented together with exemplary analysis and possible applications. The difficulties of the method are discussed.     

一种可实现高精度时间同步的数据传输方法

KM2A探测器阵列是高海拔宇宙线观测站(LHAASO)的主体探测器阵列之一,近7000个探测器平均分布在1.3 km 2的实验范围内。针对大面积分布式布局的高能物理实验中读出电子学系统的时间同步和数据传输问题,提出一种可实现高精度时间同步的数据传输方法。借助TCP/IP协议栈和White Rabbit时钟同步技术融合时钟网络与数据网络,TCP/IP协议栈在仅保留PC通信协议的基础上,无需增加额外硬件,即可实现高效可靠的数据传输和高精度时钟同步。测试结果表明,该方法可以实现探测器阵列内LHAASO KM2A读出电子学插件间时间同步精度优于1 ns,同时保证了数据传输的可靠性。