爆电换能脉冲大电流输出研究

 基于爆电换能原理,使用掺铌的PZT 95/5陶瓷组装换能器件,在垂直工作模式下,对爆电电源LRC电路响应进行了理论分析,并开展了脉冲大电流输出实验研究。实验采用多组PZT 95/5铁电陶瓷并联,利用平面波发生器作为冲击加载手段,获得了峰值5 kA以上的脉冲大电流,初始电流上升速率可达10~20 GA/s。实验结果与理论设计符合较好。     

一种大功率窄脉冲半导体激光器测试台的研制

大功率窄脉冲半导体激光器主要光电性能参数为:输出峰值光功率、阈值电流、正向电压、上升时间、峰值波长、光谱半宽、半强度角.根据激光制导系统对大功率窄脉冲激光器参数的特殊测试要求,研制一种大功率窄脉冲激光器测试平台,将小型化大功率激励器功放模块、大范围可调DC-DC模块、信号源板、激光器座、光学准直镜集成在一个平台上,与峰值功率计、光谱仪、CCD摄像机等仪器配合,可测出大功率窄脉冲激光器的峰值功率、峰值波长及波长随温度变化的漂移特性、发光芯均匀性等参数.介绍了大功率窄脉冲激光器测试台的特点,并对测试结果作了论述.     

主动光学技术在制造标准大反射镜中的应用

介绍了利用主动光学技术校正大型标准反射镜残余面形误差和重力变形的方法 ,研制了用于施加局部作用力的工具———机械式作动器的结构与性能 ,作用力的测定方法 ;位于不同位置的作用力引起的镜面变形量的测定与分析 ,与镜面最小面形误差对应的作动器作用力控制矩阵的求解等。对一块Φ2 30mm、中心厚 18mm、R880mm、玻璃材料为K 9的标准球面镜进行了面形误差校正实验 ,取得了较明显的校正效果。     

PZT 95/5陶瓷电致失效机理研究

对PZT 95/5陶瓷在直流电场、脉冲方波电场以及半正弦波电场作用下的失效机理进行了理论和实验分析.结果表明:在直流作用下,其失效机理以热-电耦合失效为主;而在脉冲电场作用下,考虑振动冲击效应以及相关的力谱分布,脉宽越短,能量向高频偏移,越可能发生力-电耦合失效;当脉宽增加,PZT 95/5陶瓷失效机理将从力-电耦合失效逐步转变成直流失效模式. 关键词： PZT 95/5 失效机理 直流电场 脉冲电场     

悬线式物镜力矩器中频段共振理论及实验分析

悬线式物镜力矩器是高密度光盘系统中关键部件——光学头的可执行机构,其运动特性决定着光学头的读盘能力。在光学头研制、生产及测试中发现某些力矩器频率特性曲线的线性工作区内出现共振,它会导致光学头的读碟能力下降。通过对力矩器可动部建模、ansys仿真及实验分析,得出力矩器可动部的质心和力心不重合将导致其在中频段内发生扭转共振。实验结论对悬线式物镜力矩器设计、评价和生产都有重要的指导意义。     

Development of Paper Actuators Based on Carbon-Nanotube-Composite Paper

We propose a unique soft actuator—a paper actuator—based on carbon-nanotube-composite paper (CNT-composite paper), which is a composite of carbon nanotubes (CNTs) and paper. CNT-composite paper has highly efficient properties because of the contained CNTs, such as high electrical conductivity and semiconducting properties. We are considering using CNT-composite paper for various devices. In this study, we successfully developed a paper actuator. We determined the structure of the paper actuator by referencing that of bucky-gel actuators. The actuator operates using the force generated by the movement of ions. In addition to making the paper actuator, we also attempted to improve its performance, using pressure as an index and an electronic scale to measure the pressure. We investigated the optimal dispersant for use in paper actuators, expecting the residual dispersant on the CNT-composite paper to affect the performance differently depending on the type of dispersant. Referring to research on bucky-gel actuators, we also found that the addition of carbon powder to the electrode layers is effective in improving the pressure for paper actuators. We believe that the paper actuator could be used in various situations due to its ease of processing.     

Inspection of interfaces between corroded steel bars and concrete using the combination of a piezoelectric zirconate-titanate transducer and an electromagnetic acoustic transducer

We have conducted an inspection of the interface between a steel bar and concrete using the combination of a piezoelectric zirconate-titanate transducer (PZT) and an electromagnetic acoustic transducer (EMAT). The PZT is used for generating elastic waves by mechanical vibration and then the EMAT is used for receiving the transmitted ultrasonic guided waves. This arrangement is made in order to overcome the major shortcomings of the PZT, i.e., the requirement of a couplant, and of the EMAT, i.e., relatively low transmitted ultrasonic energy. To investigate the applicability of this technique in the field, outside the laboratory environment, the experiments are conducted on different types of steel bars: corrosion-free, naturally corroded, and zinc-coated as well as corroded bars. It is shown that the PZT-EMAT combination is very effective for inspecting the steel bar-concrete interface. Using this technique, small separation at the steel bar-concrete interface can be effectively detected for corroded as well as corrosion-free specimens. This method can be applied in the field to pre-stressed tendons and soil nails, where one side of the reinforcement is exposed.     

Effect of excess Pb on crystallinity and ferroelectric properties of PZT(40/60) films on LaNiO3 coated Si substrates by MOD technique

Pb(Zr_0.4Ti_0.6)O₃ [PZT(40/60)] films were deposited onto LaNiO₃ (LNO) coated Si substrates by metal-organic decomposition (MOD) technique. Excess Pb was incorporated in the film by using excess Pb (2%–15%) in the solution. The crystallinity and ferroelectric properties of PZT films were investigated by using X-ray diffraction (XRD), RT66A test system and HP4194 impedance analyzer, respectively. Rayleigh law was employed to analyze the defect concentration in the films. The results show that all the PZT films show the (1 0 0) preferential orientation with complete perovskite structure except for the 2% film displaying some pyrochlore phase. The (1 0 0) preferential orientation is mainly attributed to LNO bottom electrode, which has the highly (1 0 0) preferential orientation. The 10% film shows the best polarization and dielectric properties. The remnant polarization and coercive field are about 10.1 μC/cm² and 73 kV/cm under an electric field around 330 kV/cm, respectively. And the dielectric constant and dissipation factor are about 656 and 0.022 at a frequency of 1 kHz, respectively. The good ferroelectric properties of the 10% film are mainly attributed to the low defect concentration in the film.     

以有效值计算的热声键合PZT换能器阻抗分析

在热超声芯片键合过程中,PZT换能器阻抗是键合系统的一个重要的研究参数。本文在提取PZT换能器驱动电信号实部数据的前提下,采用连续加窗的有效统计值计算的广义阻抗表征整个键合周期内的PZT换能器阻抗变化,由此获得键合过程PZT换能器阻抗的动态变化规律。文中详细介绍了PZT换能器阻抗的试验方法,并分析了试验结果。     

Fabrication of the hydrogen resistive ferroelectric film of the (Pb0.72La0.28)Ti0.93O3/Pb(Zr0.52Ti0.48)O3/(Pb0.72La0.28)Ti0.93O3 heterostructure by a pulsed laser deposition method

(Pb_0.72La_0.28)Ti_0.93O₃ (PLT)/Pb(Zr_0.52Ti_0.48)O₃ (PZT)/PLT heterostructure was fabricated by using a pulsed laser deposition method. After depositing this structure, the hydrogen annealing process was performed in the forming gas (95% N₂ + 5% H₂) at a substrate temperature of 400 °C for 30 min to study the effects of hydrogen passivation.The heterostructure was not degraded by the hydrogen annealing in contrast with the case of PZT film without buffer layers. This heterostructure showed almost no degradation in terms of the remanent polarization even after the H₂ annealing, while the PZT film exhibited 64% reduction, which is from 20.1 to 7.3 μC/cm² after the annealing. The leakage current was decreased by an order in the case of the heterostructure, while the leakage current of the PZT film increased by an order.These can be explained that the PLT bottom buffer layer works as a seeing layer to help the PZT growth and the top PLT buffer layer acts as a barrier for penetrating hydrogen atoms.