Study on the basic capacitance–voltage characteristics of organic molecular semiconductors

Capacitance–voltage (C–V) characteristics of organic molecular semiconductors attracted much research interest recently, but no convincing physical mechanism has been established so far. In this work, the C–V characteristics of pentacene-based devices have been systematically investigated at various frequencies. Only one peak occurs when the measuring frequency is less than 3 kHz or greater than 8 kHz. While within the frequency range between the two, two C–V peaks are observed with quite different dependence on temperature, which suggests that the origins of these two C–V peaks are respectively mobile holes and trapped carriers. This conclusion is also experimentally validated with the C–V characteristics of intentionally doped devices.     

电容层析成像三维成像算法研究与软件设计

为了研究循环流化床中气体 -固体的分布规律 ,基于电容层析成像得到的二维断面浓度分布 ,利用一种线性差值算法 ,构建固体颗粒的三维浓度分布。三维图像的显示采用 C 语言和 Open GL系统完成 ,并将该算法用于循环流化床中 ,结果清楚地显示了气泡的发展变化过程。     

Multiple-mode structural vibration control using negative capacitive shunt damping

This paper deals with a novel shunt circuit, which is capable of suppressing multimode vibration amplitudes by using a pair of piezoceramic patches. In order to describe the characteristic behaviors of a piezoelectric damper connected with a series and a parallel resistor-negative capacitor branch circuit, the stiffness ratio and loss factor with respect to the non-dimensional frequency are considered. The mechanism of the shunt damper is also described by considering a shunt voltage constrained by shunt impedance. To obtain a guideline model of the piezo/beam system with a negative capacitive shunting, the governing equations of motion are derived through the Hamilton’ s principle and a piezo sensor equation as well as a shunt-damping matrix is developed. The theoretical analysis shows that the piezo/beam system combined with a series and a parallel resistor-negative capacitor branch circuit developed in this study can significantly reduce the multiple-mode vibration amplitudes over the whole structural frequency range.     

抗寄生干扰的小电容测量电路研究

在测量含有导电元素的多种成份的混合液体时，将需要抗寄生干扰的传感器，这是流体无损检测应用中迫切需要解决的理论和技术问题之一。带电元素的混合流体可用电容器模型来描述，因而问题变成抗寄生干扰的高频小电容测量。本文首先简要分析了现有的电容测量方法的优缺点，其中包括谐振法、电桥法、振荡法和充放电法。然后重点给出了一种新的抗寄生干扰的测量电路，文中包括全面考虑各种干扰的电路模型，传递函数，传感器灵敏度及实验结果。该电路具有结构简单、容易实现、抗寄生干扰等优点     

基于相关检测的电容传感器的研究

介绍了一种高精度的电容传感器，应用相关检测技术，利用集成乘法器AD835来检测电容传感装置电容量的微小变化。这种方法比传统的电容检测传感器精度提高数百倍，而且系统不受外界缓变量的影响。该系统已在纤维检测方面得到很好的应用。     

一种工业用高频抗杂散小电容测量电路

介绍了一种工业用高频抗杂散小电容测量电路。该电路基于电荷转换原理,并采用差分结构产生输出信号。它有直至几兆赫兹的可编程测量频率。廉价且易于单片集成。通过采用特殊的开关安排,可以消除包括开关元件在内的杂散电容的影响,使得测量电路具有好的稳定性和线性衣０．３ｐＦ的分辨率。     

电容型设备及避雷器的绝缘在线检测

针对电容型设备及避雷器的绝缘在线检测的有关问题,进行了论述,说明了在线检测的必要性。     

高校教材《电磁场》若干问题正误

指出将面电流与其密度的关系式简单地表示成面电流等于面电流密度的线积分是错误的,并给出了正确的关系,指出两电流以元间的作用力正比于它们的矢量积这一论断是错误的,指出电容量公式对于极板间存在自由电荷电容并不适用。     

电容传感器的敏感探头

本文论述了电容传感器几种适用的敏感探头:圆筒内表面探头、圆柱外表面探头、平面探头、同轴圆柱探头的结构原理与电容量的计算方法,并指出各自的适用范围。     

电容式油水界面液位传感器的设计

本文设计了圆柱形电容传感器,其输出为4￣20mA信号,可与自动控制仪表及相应执行部件构成油水界面自动监控系统。只需通过简单的标定,便可用于各种油品。圆柱形传感器测量精度可达±1mm,可以在室温到100℃变温环境下正常工作。