Measurement of piezoelectric modulus by pulsed excitation of piezoelectric ceramic elements

The possibility of measuring the piezoelectric modulus by exciting piezoelectric ceramic components with a radio pulse is considered. It is shown that there is a relation between the piezoelectric modulus and the rate of change of the current envelope at the beginning of the transient. Theoretical relations are derived. __________ Translated from Izmeritel’naya Tekhnika, No. 10, pp. 71–72, October, 2006.     

磁致伸缩作动器的设计与性能分析

在分析超磁致伸缩材料特性的基础上设计了一种微位移作动器．通过有限元分析，对作动器的结构进行优化，得到均匀的偏置磁场和激励磁场；设计了预压力加栽结构和强制冷却结构．对该作动器的动、静态性能进行了测试，结果表明：作动器基本上工作在线性区域内，其位移伸缩量大，低频动态性能较好，高频谐波分量影响较小，相位延迟较小，同时也证明了对作动器的磁场分析和结构优化是正确的．     

一种双足驱动直线超声波电动机的设计

设计了一种单边双足驱动的面内振动直线超声波电动机，其定子采用了一片铜板和八片压电陶瓷构成的复合结构，压电点陶瓷沿着厚度方向极化，对称安装在矩形铜板的两个表面上。建立了该电机的机电耦合动力学模型，通过仿真确定了驱动足的位置，并试验研究了电机的特性。     

一种新型非接触圆盘压电微电机

提出了一种新型圆盘压电微电机，定子与转子间是非接触型的。定子工作在砘振动模态，并激励定子产生圆周方向单向行波。该电动机具有结构简单、易于制作、转速高等特点，电动机测试最高转速达到2225r／min。     

New explicit formulas for the effective piezoelectric coefficients of binary 0-3 composites

The explicit formula for the effective dielectric constant of binary 0-3 composites (Poon and Shin, J. Mat. Sc. 39 (2004) 1277–1281) is extended into two explicit formulas for the prediction of the elastic properties of macroscopically isotropic 0-3 composites. By combining them with the explicit effective dielectric formula into a calculation scheme (Wong et al., J. Appl. Phys. 90 (2001) 4690), we obtained two new explicit formulas for the prediction of the d ₃₁ and d ₃₃ values for binary 0-3 piezoelectric composites. These two explicit formulas are applicable even when the inclusion volume fraction is high. Comparing with existing experimental data, they are found to fit more favorably than those predicted by Wong et al. and others. Also, being explicit makes these formulas much easier to be embedded into other effective property calculations for binary 0-3 composite materials.     

Investigation on the design and synthesis of new systems of BNT-based lead-free piezoelectric ceramics

Three primary differences between BNT- and PZT-based ceramics were analyzed from the composition and the active component of the materials. Based on the analysis the authors’ group developed the new idea of the design of the multiple complex in the A-site ions of BNT compounds. (Bi_0.5Na_0.5)²⁺, Bi³⁺ and Na⁺ in the ABO₃ structure are defined as A-site, A₁-site and A₂-site ions, respectively, and A, A₁ and A₂-site ions can be simultaneously or singly substituted partially by alkaline-earth metal ions, metal ions with +3 valence and metal ions with +1 valence, respectively. Under this consideration, Several new systems of Bi_0.5Na_0.5TiO₃ (abbreviated as BNT)-based lead-free piezoelectric ceramics were proposed. These ceramics can be prepared by conventional ceramic techniques and have excellent piezoelectric performance. Among these materials, Bi_0.5(Na_1−x−y K _x Li _y )_0.5TiO₃ possesses higher piezoelectric constant (d ₃₃ = 230 pC/N), higher electromechanical couple factor (k _p = 0.40), larger remanent polarization (P _r = 38.9 μC/cm²) and a better P-E hysteresis loop until about 200^∘C. This work was supported by the projects of NSFC (50410179), (50572066), and (59972020), and NAMMC (2001-AA325060).     

磁致伸缩换能器辐射板活塞振动幅值的近似计算

以柱形磁致伸缩换能器为对象,建立了其辐射板在驱动力作用下的运动模型,给出了一阶解析解,并与实验结果进行了比较.结果表明,对一阶振动,该解析解具有足够精度,可方便应用于换能器辐射板的动力学设计.     

压电基因传感器检测芽孢杆菌靶序列研究

在石英晶体微天平(QCM)上用生物素亲和素法和自组装法2种不同的方法固定寡核苷酸探针,构建压电基因传感器,对芽孢杆菌靶序列进行实时检测。结果表明:生物素亲和素法固定探针效果更好,靶序列浓度为0.05~0.5μmol/L时,有很好的线性关系,线性回归方程为Y=93.88X+10.88(R=0.989 0,N=6,P<0.001),非线性误差为±4.7%。该传感器特异性较好,能够识别错配3个碱基的序列。     

短路型石英传感器的平面冲击响应

石英传感器已广泛应用于冲击应力波剖面的测量。对不同宽厚比短路型石英传感器在冲击作用下的动态响应特点进行了研究,试验结果表明:不同宽厚比短路型石英传感器的动态响应特点基本相同,其压电系数与冲击应力满足线性关系;传感器压电系数斜升幅度与宽厚比的关系为:当石英传感器的宽厚比大于1.4时,其压电电流的斜升幅度基本不随宽厚比变化,而小于1.4时,压电电流的斜升幅度受边缘效应的影响明显上升,这表明宽厚比小于1.4的石英传感器可应用于实际工程测量。     

引入乘客动力学的1/2车辆液压主动悬挂系统建模与控制

建立了引入乘客动力学以及考虑液压装置动态特性的1/2车辆非线性主动悬挂模型，并在此模型的基础上提出了线性二次型最优控制与非线性Backstepping方法相结合的控制策略．仿真结果验证了该控制策略的有效性．