现代精密测量中的压电生物传感器

压电效应与现代生物技术相结合产生的压电生物传感器在微量物质的精确测定方面具有很大的潜力，这种传顺不但体积小，重量轻，而且灵敏度高，准确性好，是一项很有前途的精密测量技术，简要介绍了压电生物传感器的基本原理，结构和应用。     

双层压电结构超声波传感器的研究

为获得三频或宽频超声波传感器，本文提出了一种新型双层压电结构超声波传感器，文中从理论上分析研究了电容对其频率特性控制的原理，同时，在２ＭＨｚ频率范围进行了实测验证，理论与实测结果吻合较好。     

表面声波传感器及其应用

本文简要介绍多种表面声波传感器的结构、特点、应用及其研究进展概况。表面声波传感器依其波型分类,主要包括瑞利波、水平切变声板波、乐甫波和兰姆波传感器;其应用领域根据作用特点大致可分为物理传感器和化学、生物传感器,前者较易实现,后者特异性强,需要针对具体情况作更细致研究。由于表面声波的传播速度和相位对周围环境的参量变化极为敏感,因此有关传感器具有很高的灵敏度和广泛的应用领域。     

压电免疫传感器的设计及应用

压电免疫传感器作为一种新型生物传感器,是利用压电元件的质量敏感性质,结合生物免疫识别特性而形成的一种自动化分析检测传感器,它可对钦种抗原或抗体进行的定量测定,并可有于反应动力学的研究,具有高特异性、高灵敏度、响应快、小型简便等特点。本文利用石英晶体产生体波厚度剪切振动模式,由双通道系统进行频率变化的测定。采用氨基硅烷膜固定抗体来定量检测溶液中人体免疫球蛋白Ｉdisplay status     

压电晶片传感器监测金属薄板的腐蚀

激励压电晶片传感器产生Lamb波并用于监测金属板材的腐蚀,由信号的相关系数表征腐蚀对在板中Lamb波传播特性的影响。实验结果表明在Lamb波模态中A₀模式受腐蚀影响大,适合用于监测金属的腐蚀。Lamb波通过腐蚀区域后由于频散以及信号幅度和相位的变化对采集的损伤信号与健康状态信号的相关系数有影响。在腐蚀区域直径一定的情况下,对应的相关系数并不随腐蚀深度的增加而单调递减;在腐蚀深度一定时,相关系数随腐蚀区域直径增加而单调递减。     

压电矢量传感器的低噪声设计

针对压电矢量传感器的低噪声设计问题,建立了基于压电敏感器件、悬挂结构、前置放大电路及电缆的同振式矢量传感器等效自噪声分析模型;结合敏感器件的低噪声设计、悬挂结构对自噪声的影响以及前置放大电路低噪声匹配等内容提出了一种低噪声设计方法。设计了低噪声矢量传感器样机,研制了自噪声测量平台并对样机进行了测试。结果表明:样机的等效噪声声压谱级达到了55.5 dB/√Hz2@200 Hz,低于同频率Knudsen零级海况下海洋环境噪声;测试结果与设计结果相符,验证了低噪声设计方法的有效性,也为压电矢量传感器的低噪声设计提供了理论依据。     

基于压电加速度传感器的振动测量系统研究

为实现对振动的有效测量,构建了压电式加速度传感器的振动测量系统;分析了压电加速度传感器的力学模型及基本原理,并采用灵敏度比较法标定传感器,阐述了测振系统的硬件组成及软件设计方法,搭建了工程实际测振的实验模型;实验结果表明,该测振系统运行稳定,可移植性强。     

PVDF压电传感器及敏感单元设计关键技术

研究了聚偏二氟乙烯(PVDF)柔性压电传感器敏感单元设计关键技术和工艺。通过传感器敏感单元设计、电极制作、极化和封装研究实现功能,结合动态冲击压缩实验,对自主研制的PVDF传感器在不同压力段进行标定和A类不确定度评价,实验数据的A类不确定度优于10%,说明所研制的PVDF压电传感器精度高、重复性好,能够满足0.3~10.0 GPa动态冲击压力测量应用需求。目前产品设计水平已达到6级,后续将进一步开展更高压段有效性的应用设计、温度补偿效应研究和工程化产品设计。     

一种可提高压电复合材料d33和dh值的新型结构传感器

原理分析和实验结果证明了：通过一种含有空腔的金属电极与压电复合材料的界面作用，发迹了应力的作用式，提高了ｄ３３值；并使数值符号相反的ｄ３３和ｄ３１均对ｄｈ值起加大作用。     

垂直于电场和极化方向辐射声波的压电复合材料

本文介绍了一种２－２型压电复合材料，使其中的极化方向和所加电场方向相同，并垂直于该方向而辐射声波。     

压电材料的研究新进展

本文就近些年来国内外压电材料技术研究进展中呈现的无铅化、高性能化、薄膜化的新趋势进行了综述,并对今后的研究提出一些建议。     

功率型压电陶瓷的分类及研究进展综述

功率型压电材料是大功率换能器及压电变压器等的核心功能材料,广泛应用于声纳系统、超声检测、振动控制及其它机电设备等。尽管其组成和制备方法与其他压电材料类似,但特定的使用目的对功率型压电材料提出了特殊的综合性能要求。本文基于对功率型压电陶瓷材料组成的分类归纳,综述了该材料的性能特点、国内外研究进展,并对现存问题和应用前景进行了论述。     

Fabrication and characteristics of thin disc piezoelectric transformers based on piezoelectric buzzers with gap circles

This paper investigates design, fabrication and test of thin disc piezoelectric transformers (PTs) based on piezoelectric buzzers with gap circles at different diameters of the gap circles. The performance test is focused on characteristics of voltage gains, including maximum voltage gains and maximum-gain frequencies, for each piezoelectric transformer under different load conditions. Both a piezoelectric buzzer and a gap circle on a silver electrode of the buzzer are needed to build any type of the PTs. Here, the gap circle is used to form a ring-shaped input electrode and a circle-shaped output electrode for each piezoelectric transformer. To do so, both structure and connection of a PT are first expressed. Then, operating principle of a PT and its related vibration mode observed by a carbon-power imaging technique are described. Moreover, an experimental setup for characterizing each piezoelectric transformer is constructed. Finally, effects of diameters of the gap circles on characteristics of voltage gains at different load resistances are discussed.     

压电管堆式宽带换能器*

研究了一种具有管状叠堆结构的圆管换能器,其敏感元件是由纵向极化压电陶瓷单元组成的薄壁管状压电叠堆,探讨利用管状叠堆纵向和径向振动耦合实现宽带发射。利用压电柱壳振动理论推导了管堆的频率方程,分析了换能器的纵向和径向模态的振动耦合特性。在理论分析的基础上利用有限元方法对换能器的带宽和发射电压响应进行优化并研制换能器样机。测试结果表明,纵向极化的管状压电叠堆结构具有良好的发射电压响应和宽带特性,与理论及仿真结果相符。     

压电MEMS超声换能器研究进展

MEMS(micro-electromechanical systems)超声换能器(MEMS ultrasonic transducer,简称MUT)是采用微电子和微机械加工技术制作的新型超声换能器。与传统超声换能器相比,MUT具有体积小、重量轻、成本低、功耗低、可靠性高、频率控制灵活、频带宽、灵敏度高以及易于与电路集成和实现智能化等特点。是超声换能器的重要的研究方向之一。MUT的研究主要包括压电MUT(piezoelectric MUT,简称PMUT)和电容MUT(capacitiveMUT,简称CMUT)两个方面。本文概述了PMUT研究的发展进程和研究成果,展望了PMUT的研究和应用前景。     

Fabrication of piezoelectric components for a tunable and efficient device for DNA delivery into mammalian cells

We fabricated three piezoelectric components (PZT) that can produce ultrasonic waves with various generated power in order to improve the delivery of DNA molecule and polymer/DNA complexes into cells. Two cationic polymers (PEI and PDMAEMA) were interacted with DNA to form nano-scaled DNA/polymer complexes with/without the help of PZT devices. The application of PZT devices under optimal conditions helped to avoid cytotoxicity and greatly increased the transfection (DNA delivery) efficiency of these complexes in mammalian cells. The cytotoxicity and transfection efficiency were found to be correlated with the PZT-generated power, waveforms and duration of ultrasonic treatment. There was no observable cytotoxicity in our experimental models and, a maximum transfection efficiency 700% greater than that of polymer/DNA complexes without applying ultrasound was achieved. The transfection efficiency of plain polymer/DNA complexes (without PZT treatment) corresponded to a 630-fold increase in comparison to the naked DNA. The waveforms of generated ultrasound greatly influenced the transfection efficiency, while cytotoxicity was not significantly affected. This means that, for optimal DNA delivery, duration of the peak voltage (V_max/Div) also plays a role. In addition, the generated waves from PZT do not cause dissociation of polymer/DNA complexes or a change in the particle sizes of these complexes. In conclusion, these results suggest that the operation of PZT devices can be a tunable/safe way to greatly improve DNA delivery for gene therapy.     

基于球形压电陶瓷的耐压水听器

利用球形压电陶瓷自身所具有的耐压能力,采用径向极化空气背衬压电球壳换能器作为声学接收敏感元件,设计并制作了一种球形耐压水听器。首先对其低频开路接收灵敏度和谐振频率等声学特性进行了分析和有限元仿真,然后对其强度和稳定性等耐压性能进行了分析和有限元仿真,最后对其声学性能和耐压能力进行了测试。测试表明,该球形耐压水听器的直径为36 mm,工作频段为50 Hz～10 kHz,低频接收灵敏度为-198.4 dB (0 dB=1 V/μPa),等效自噪声谱级为46.5 dB@1 kHz,其耐压深度可达3000 m。该耐压水听器为大深度水听器设计提供了参考,在深水声学领域具有重要的应用价值。     

On the propagation of long thickness-stretch waves in piezoelectric plates

We study the propagation of thickness-stretch waves in a piezoelectric plate of polarized ceramics with thickness poling or crystals of class 6 mm whose sixfold axis is along the plate thickness. For device applications we consider long waves with wavelengths much longer than the plate thickness. A system of two-dimensional equations in the literature governing thickness-stretch, extensional, and symmetric thickness-shear motions of the plate is further simplified. The equations obtained can be used to analyze piezoelectric plate acoustic wave devices operating with thickness-stretch modes.     

Quantum effect on parametric amplification characteristics in piezoelectric semiconductors

Using QHD model the parametric interaction of a laser radiation in an unmagnetised piezoelectric semiconductor has been studied. It is found that the Bohm potential in the electron dynamics enhances the gain coefficient of parametrically generated modes whereas reduces the threshold pump intensity.     

Hysteresis compensation of piezoelectric actuators: The modified Rayleigh model

In this study, we develop a novel modified Rayleigh model for hysteresis compensation in piezoelectric actuators. Piezoelectric actuators suffer from hysteresis, in large drive fields of more than 100 V, which can result in serious displacement errors. The typical phenomenological approach is to use the Rayleigh model; however, this model gives more than 10% difference with experiments at the large electric fields of more than 1 kV/mm. Furthermore, there are no studies that apply the Rayleigh model to the compensation of precision actuators, such as stack actuators; it has only been applied in the study of the physical properties of piezoelectric materials. Therefore, we propose a modified Rayleigh model, in which each coefficient is defined differently according to whether the field is increasing or decreasing to account for asymmetry at the high fields. By applying a computer-based control from an inverse form of this modified Rayleigh model, we show that we can compensate for hysteresis to reduce the position error to less than five percent. This model has the merits of reducing complicated fitting procedures and of saving computation time compared to the Preisach model. Specifically, this model cannot only predict the hysteresis curves in all local fields using only one fitting procedure, but also make it possible to control the displacement of various piezo-based actuators without expensive sensors, based on the charge-based model.