电磁脉冲模拟装置用3 MV中储电容器的研制

介绍了一台大型垂直极化有界波模拟装置所用中间储能电容器（简称中储电容器）的设计过程和实验结果。电容器采用基于元件和组件的模块化设计,呈锥台状结构,支撑壳体为真空工艺玻璃钢材料。电容器容值由模拟装置等效的二级脉冲压缩回路决定,取值为1.8 nF。电容器内部绝缘介质为十二烷基苯,外部绝缘介质为45#变压器油,设计耐压3 MV,其绝缘长度主要由元件的体绝缘特性决定。采用三维电磁仿真软件估算中储电容器与中储开关构成回路的电感为659 nH,接近于实测数据623 nH。电容器上脉冲电压的测量通过对电容器电流进行积分来获取,而电流的采集采用封装在SF₆气体中的3个膜电阻并联后所构成测量模块实现。实际运行数据表明,中储电容器容值达到设计值,测量探头标定系数稳定,在工作电压3.1 MV条件下未发生绝缘问题。     

非平行板电容器电容的又一算法

应用平行板电容器电容的概念和并联电容器电容公式,给出了非平行板电容器的电容及电场分布.     

非平行板电容器电容和电场的两种计算方法之讨论

介绍求解非平行板电容器电容和电场的两种计算方法,一种是从平行板电容器的概念入手的求解方法,另一种是利用电场能量和电容器的能量公式,解出非平行板电容器的电容和电场分布.通过对上述两种方法的讨论,指出第二种方法,严格、简捷易懂,图像清晰,且颇具新意.     

超导量子器件片上皮法电容的制备及测量

片上集成电容是超导量子芯片上的核心器件，其数值一般在百飞法(fF)至皮法(pF)范围.采用常规微纳加工技术在蓝宝石基片上制备了铌-氧化硅-铝(Nb/SiO₂/Al)平行板电容.利用刻蚀工艺制备了平行板电容器的下极板Nb,利用剥离工艺制备平行板电容器的上极板Al和介电层SiO₂.室温下利用锁相放大原理和桥式电路原理测定电容大小，两种方法测定电容值基本一致，表明锁相放大原理测试pF级电容的可靠性.利用该电容与铝基约瑟夫森结组成谐振器，制备了中心频率位于4.35 GHz的约瑟夫森参量放大器.在稀释制冷机中10 mK温度下测定直流偏置谐振器的磁通-频率相位图，拟合数据获得的电容值与室温测定电容值接近，表明在mK、GHz条件下工作的片上集成电容可在室温、kHz条件下测定其数值大小.     

PN结对交流信号相位的影响

交流小信号被PN结和电容分压，且电容值远远大于PN结电容值时，大电容两端的电压是很小的交变电压，该信号的相位与PN结的内阻(正向)有关．把PN结当做一个电容和一个电阻并联，可定性解释这种关系．     

PN结对交流信号相位的影响(续)

当1个交流小信号被1个PN结和1个大电容分压,且该电容的电容值远大于PN结电容时,大电容两端的电压与PN结电容成正比,该信号的相位与PN结的电阻以及信号的频率有关.把PN结当作1个电容和1个电阻并联,可定性解释该信号的相位与PN结正向电阻、与加在PN结两端的直流反向偏压、在零直流偏压下与交流信号频率的关系.     

关于非平行板电容器电容计算的讨论

用串联方法计算非平行板电容器的电容，简便地得到与其他方法相同的结果。     

The electrostatic capacitance of an inclined plate capacitor

Considering the dimension and relative position of the two plates, the capacitance of an inclined plate capacitor is precisely calculated. Conformal mappings are employed and elliptic functions are used for achieving the general result. Taking the fringing effect into account, the inner capacitance and outer capacitance of the inclined angle are added to obtain a reliable result. The expression for computing the fringing capacitance of a parallel-plate capacitor and the capacitance of a parallel-strip transmission line in a plane are presented as special cases.     

The coupling effect of air-bridges on broadband spiral inductors in SiC-based MMIC technology

The coupling effect of air-bridges on broadband spiral inductors in SiC-based MMIC technology has been investigated deeply. The fabricated 1-nH spiral inductor on SiC substrate demonstrates a self-resonant frequency of 51.6 GHz, with a peak Q-fact of 12.14 at 22.1 GHz. From the S-parameters measurements, the exponential decay phenomenon is observed for L, Q-factor, and SRF with the air-bridge height decreasing, and an analytic expression is concluded to exactly fit the measured data which can be used to predict the performance of the spiral inductor. All the coefficients in the formula have specific meaning. By means of establishing the lumped model, the parasitic coupling capacitance of the air-bridge has been extracted and presents the exponential decay with the air-bridge heights decreasing which indicates that this capacitor is directly related to the coupling effect of the air-bridge. Through the electromagnetic field distribution simulation, the details of the electric field around the air-bridge have been presented which demonstrate the formation and the variation principles of the coupling effect.     

矩形柱电容器电容的简单计算方法

用简单方法计算矩形柱电容器的电容 ,并指出文献 [1 ]中的“电容特性普遍公式”实质上就是无限多个平行板电容器电容的串联公式 .     

平行板电容器的尺寸效应

本文分别研究了平行圆形板和矩形板电容器的电容随其尺寸变化的规律.对于每种电容器,首先假设电荷在极板上均匀分布,由此能较简便地得出电容的近似值,然后用Ansoft软件作有限元仿真,得出更精确的数值.通过对比发现,用均匀带电近似得出的结果能够正确地反映电容随其尺寸变化的趋势,优于教科书中的平行板电容器公式;但其数值偏小,原...     

非平行板电容器的电容和电场的计算

本文采用保角变换的方法计算非平行板电容器的电容和场强,本方法与以往所见的方法不同,它简洁、严谨     

On the question of the error in the partial capacitance method

An analytical method is proposed for calculating the capacitance of a planar capacitor constructed in the form of a two-layer structure. The method is used to calculate the capacitance of a planar capacitor containing a ferroelectric film. A number of calculations were performed to check the accuracy of the partial capacitance method. The calculations made it possible to determine the limits of accuracy of the partial capacitance method for a permissible calculational error of ±3%. Zh. Tekh. Fiz. 69, 8–13 (April 1999)     

电桥法测杨氏模量的实验研究

本文引入了电桥法测量杨氏模量,用自制平行板电容器对传统的实验装置进行改进,用电容的变化来表征微小位移的变化,通过实验原理、误差分析,结合测量结果,由此给出了一种测量杨氏模量的新的方法.     

Study of dielectric behaviour of woven fabric based on two phase models

Dielectric constant of textile fibres plays very important role in electrostatic behavior of textile materials during its processing and use. The effective dielectric constant of textile materials is defined as the ratio of capacitance of a parallel plate capacitor with the textile material to that of the capacitor without the textile material. This paper presents three models considering textile woven fabric as a mixture of air and fibre to relate dielectric constant of fibre material and the effective dielectric constant of fabric. The mathematical models have taken into account measured fabric parameters. Plain woven fabrics of high density polyethylene monofilament yarns were used to do the actual measurement and results of three models based on these fabrics are compared.     

Static dielectric constant assessment from capacitance over a wide range of electrode separations

Static dielectric constant extraction from two-electrode capacitance measurement over a wide range of electrode separations and dielectric constants involves careful assessment of fringe fields. Finite-element method has been employed to compute capacitance and quantify fringe fields for parallel electrode capacitor of (finite thickness, radii r, electrode separation d), with a homogeneous dielectric medium extending up to the geometric limits of the electrodes. Two distinct regimes, in the fringe field contributions are seen. A procedure to extract the static dielectric constant has been proposed for the first regime and a validation has been provided for the same.     

Modeling and calculation of the capacitance of a planar capacitor containing a ferroelectric thin film

The capacitance of a two-layer planar capacitor containing a thin layer of SrTiO₃ is calculated by conformal mapping using the partial capacitanc e method. Simple formulas are obtained for approximation calculation of the capacitances of individual components of a planar structure, and their limits of applicability are determined. A relation for the capacitance of a planar capacitor is derived which takes account of the size effect in a ferroelectric film within the context of the partial capacitance method. The calculated result is compared with the experimentally measured capacitance. Zh. Tekh. Fiz. 69, 1–7 (April 1999)     

An experimental set-up for the study of electromechanical properties of conducting polymer films

An experimental set-up have been designed and fabricated to study the electromechanical properties of a thick film of conducting polymer under load. Extension of the films versus voltage has been measured in terms of change in capacitance of parallel plate capacitor constituted by metal pan and a fixed metal plate. HP 4284A impedance analyzer measures absolute value of the capacitance. Change in capacitance is related to change in distance by pre-calibrating the assembly using traveling microscope. A computer programme is developed to convert the capacitance value with the corresponding distance and simultaneously plotting the graph between changes in length of polymer film versus applied voltage.The assembly has been used to study the electrochemomechanical behavior of solution cast polyaniline films (∼50 μ thick). During first cycle the length is enhanced by about 6% of original value, while repetitive value of extension is ≅2.8%, in subsequent cycles. This value closely matches to that reported in literatures.     

相干平行板电容器对外场的动态响应

基于介观体系动态响应的自洽理论,讨论了介观相干平行板电容器的电容.结果表明相干电容器的电容对外场频率有很强的依赖关系,并且是随频率变化的复变函数.该电容随频率的变化关系呈现出一个非常有意义的特性,即电容虚部曲线有一个较尖锐的峰,它正好与电容实部的极小位置相对应,而进一步研究发现它们与该电容体系中的类等离子体激发相联系.另外,也讨论了介观电容的尺寸效应,发现当极板间距很大时,电容值和宏观的几何电容结果趋于一致.     

一种用于强激光系统的高比能脉冲电容器

 为了满足“神光-Ⅲ”原型装置能源系统的需要,桂林金属膜电容器厂研制成功一种高比能脉冲电容器,其尺寸为295 mm×138 mm×730(830) mm,额定电压25 kV,额定电容及偏差为55 μF,0~5 %,损耗角正切值(2.5 kV,50 Hz)小于 0.1%,比能达0.56 J/cm³ 。对该型电容器进行性能测试,所得电容偏差都在2%~5%范围,损失角正切值小于0.05%;极间耐压试验全部通过,极-地耐压试验全部通过。寿命试验中,放电电流5 kA,1×10⁴次充放电后,电容量下降1.8%。该型电容器目前已投入运行,工作情况良好。