超精密磨削微进给工件平台的研制

采用弹性铰链作为预紧机构,采用压电陶瓷作动器作为驱动机构,设计了一种超精密磨削辅助工件平台。具有结构简单、位移分辨率高、动态响应速度快等优点。文中通过试验研究了其在开环和闭环控制下的静态和动态特性,结果表明,其中心部位静态刚度达到200N/μm,Z向的固有频率达到1289Hz。     

A generalized plane strain theory for transversely isotropic piezoelectric plates

INTRODUCTION For moderate thickness plate containing notches or holes, neither plane stress nor plane strain theory can describe its true deformation states (Jin and Hwang, 1989). This well known drawback has mo- tivated many analytical and numerical studies carried out to determine the effect of plate thickness on the in-plane stress distribution. Pioneering work on the along depth stress components, i.e. the K-M gener- alized plane strain theory was proposed by Kane and Mindlin (1956)…     

电化学DNA传感器在临床检验中的应用

针对传统DNA测定方法中存在的严重问题,提出了新型测定DNA的技术-电化学DNA传感器测定法。本文就电化学DNA传感器的工作原理和实用效果等,进行了论述。     

卤化亚汞声光器件换能器电输入阻抗

利用压电换能器等效电路网络分析法,计算了以环氧树脂为缓冲层(粘接层)的x-cutLN/卤化亚汞声光器件中换能器三层结构规一化电输入阻抗|Zj|随规一化频率f/f0的变化值,绘出了|Zj|-f/f0关系立体图。得出器件的输入阻抗是射频频率复杂的复数函数及在不同频率段分别呈现感抗和容抗特性且随电极层厚度变化而变化的结论。     

音叉的速度共振与位移共振曲线的测量和研究

利用接收线圈和压电换能片2种传感器测得音叉受迫振动的速度、位移共振曲线,通过实验比较和理论分析,证明这2种传感器所测得的物理量并不相同,同时分析和验证了2种幅频曲线的区别。对影响位移共振曲线测量结果的阻尼系数进行讨论和分析,得出:用接收线圈做传感器测得的音叉共振曲线为速度共振曲线,而用压电换能片做传感器测得的音叉共振曲线为位移共振曲线。实验的研究有利于学生对受迫振动和共振概念的深入理解,也有利于对2种传感器的正确运用。     

压电变压器应用研究

压电变压器是一种基于压电效应的固体电子器件,它利用压电陶瓷材料的正压电效应和逆压电效应,完成机械能与电能之问的相互转换,实现电压的高低变换.本文在介绍其工作原理和种类的基础之上,对现在变压器的应用做了一个简要的综述,并对其发展趋势进行展望.     

Energy harvesting with a slotted-cymbal transducer

A cymbal transducer is made up of a piezoceramic disk sandwiched between two dome-shaped metal endcaps. High circumferential stresses caused by flexural motion of the metal endcaps can induce the loss of mechanical input energy. Finite element analysis shows that the radial slots fabricated in metal endcaps can release the circumferential stresses, and reduce the loss of mechanical input energy that could be converted into electrical energy. In this letter, the performance of a slotted-cymbal transducer in energy harvesting was tested. The results show that the output voltage and power of the cymbal are improved. A maximum output power of around 16 mW could be harvested from a cymbal with 18 cone radial slots across a 500 kΩ resistive load, which is approximately 0.6 times more than that of the original cymbal transducer.     

Preparation of AlN thin films for film bulk acoustic resonator application by radio frequency sputtering

Aluminum nitride （AlN） thin films with high c-axis orientation have been prepared on a glass substrate with an Al bottom electrode by radio frequency （RF） reactive magnetron sputtering. Based on the analysis of Berg＇s hysteresis model, the improved sputtering system is realized without a hysteresis effect. A new control method for rapidly depositing highly c-axis oriented AlN thin films is proposed. The N2 concentration could be controlled by observing the changes in cathode voltage, to realize the optimum processing condition where the target could be fixed stably in the transition region, and both stoichiometric film composition and a high deposition rate could be obtained. Under a 500 W RF power of a target with a 6 cm diameter, a substrate temperature of 450 ℃, a target-substrate distance of 60 mm and a N2 concentration of 25%, AlN thin film with preferential （002） orientation was deposited at 2.3 μm/h which is a much higher rate than previously achieved. Through X-ray diffraction （XRD） analysis, the full width at half maximum （FWHM） of AlN （002） was shown to be about 0.28°, which shows the good crystallinity and crystal orientation of AlN thin film. With other parameters held constant, any increase or decrease in N2 concentration results in an increase in the FWHM of AlN.     

生物传感器技术与DNA计算结合的应用研究

与目前压电基因传感器技术和DNA计算理论相结合,设计了一种基于压电基因传感器DNA计算的方法,并把此方法应用到可满足性问题的解决上,详细论述了计算的过程,并编写程序模拟和验证算法的可行性。与以前的DNA计算方法相比,该方法具有运算和检测解的同时性,计算的准确性和并行性以及计算过程的连续性等优点,说明将传感器技术和DNA计算相结合的生物高科技技术,在DNA计算及其应用中有着巨大的使用价值。     

科技人物

王中林小组制备出高性能传感器美国佐治亚理工学院(Georgia Institute of Technology)和中科院纳米能源与系统研究所王中林教授领导的研究小组最近利用压电电子学效应对肖特基结纳米线传感器进行调节,制备出高性能传感器——pH传感器和蛋白质传感器。