电容电阻双模态成像系统的无线数据采集技术

针对传统ECT/ERT成像系统中连接数据采集部分和成像终端的连线复杂、抗干扰能力差等问题,设计了一种基于无线模块nRF24L01进行数据传输的ECT/ERT双模态成像系统;介绍了基于无线传输的ECT/ERT双模态成像系统硬件结构,采用一种简化的基于跳频的无线传输通信协议,该法可以在多台同频干扰机发送的环境下较好地避免采集数据受干扰,并实现每秒50帧数据传输;实验结果表明,采用无线跳频技术可以解决工业现场的干扰,使测量数据准确快速地传输到成像终端。     

Comparison of the RF MEMS switches with dielectric layers on the bridge’s lower surface and on the transmission line

Previously, we proposed that the dielectric layer of RF MEMS switch can be fabricated either on the transmission line, as traditional switches, or on the lower surface of the bridge. This paper presents a detailed comparison of the RF MEMS switches with different positions of dielectric layer. Through theoretically analyzing the physical model of fringing capacitance, it is revealed that different positions of dielectric layer can result in different switch capacitances. Therefore, the change of d...     

电容式水分仪的研制

介绍了基于单片式电容传感器的电容式水分仪,可实现对被测对象的无损检测。主要用于地暖供热管道渗漏和建筑物渗漏的检测。描述了水分测量系统的测量原理、硬件结构,以及软件设计结构。实践表明,该水分仪具有较高的准确性和应用推广价值。     

Dielectric‐coated conducting curvilinear surface electrostatic model for spacecraft charging applications

In this article, free space capacitance of dielectric‐coated conducting curvilinear surfaces is obtained using method of moments (MOM). The surfaces are discretized using triangular subsections. The curvilinear surfaces are represented by quadratic parametric elements. The MOM based on the pulse basis function and point matching is used. The integrand is divided into a regular and a singular part. The regular part of the integral is numerically evaluated by using the Gaussian quadrature algorithm for triangles. The Duffy transformation is used to evaluate the singular part of the integrals. Computed results are given for the capacitance of the dielectric‐coated conducting cylinder of finite axial length and truncated cone, and compared with the previously published results. © 2010 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2010.     

Extension to the analytical model of the interdigital electrodes capacitance for a multi-layered structure

Interdigital electrodes (IE) are one of the most used transducers in different technical and analytical applications with the particular importance in the field of chemical and biological sensors. With the recent demand for lab-on-a-chip devices and the need for sensors miniaturization it becomes common the use of such transducers in structures with several dielectric layers (either substrates or superstrates). In a previous a work we proposed a model for the computation of the capacitance of these multi-layered structures using the techniques of conformal mapping and partial capacitance. Until now, that model has been used in applications where the permittivity of consecutive layers monotonically decreases from layer to layer (as we move away from the electrodes plane) giving excellent results. New applications, such as the use of Si/SiO₂ substrates (to promote very smooth surfaces for electrodes deposition) or the use of passivation layers for the protection of electrodes (e.g. from liquids), among others, represent a new challenge for the computation of the overall capacitance since in these devices the permittivity can decrease from layer to layer. Under these conditions the original partial capacitance technique needs to be modified to include these new configurations. In this work we will discuss a new approach, splitting the concept of partial capacitance in parallel partial capacitance and serial partial capacitance where new conformal mapping transformations are proposed for the latter case. Hence this novel approach will extend our previous analytical model in order to account for the cases where there is a decrease in the permittivity from layer to layer. The results are compared with finite element simulation and experimental results.     

网络适配器静电放电问题分析

提出了网络适配器产品静电放电问题的分析及解决方法,并就器件的寄生电容及寄生电感参数对高速电路的影响进行分析总结,为高频滤波、防护电路的器件选型提供了一定的指导.     

多孔平面的快速边界元划分

在 3D VL SI互连寄生电容的边界元素法计算中 ,多孔平面的边界元划分是十分困难的问题 .文中提出一种快速划分多孔平面边界元的方法 ,它可高效处理非正交几何边界形状 ,形成规则的梯形元 .与全局扫描线法相比 ,有较高的划分速度、计算速度与精度     

互连寄生电容器中屏蔽导体的快速判断

应用层次式Ｚ缓冲区可视性算法的思想,实现了一种互连寄生电容器中屏蔽导体的快速判断算法,能准确地确定对电容值影响较小的导体,并加以消除,当用边界元法提取甚多环境导体对关键路径产生的寄生电容时,可在满足计算精度的条件下,显著地提高计算速度。     

基于DSP的电容电流的精确测量

近年来随着电网结构的不断变化,注入信号法测量电容电流得到了广泛的应用和重视,而在实际应用该方法的过程中有2个瓶颈问题还没有得到很好的解决,即信号源和50 Hz陷波的问题。文章针对这2个问题,提出了一种采用数字信号处理器TMS320F2812和数字频率直接合成技术相结合实现电容电流测量的新方法,详细介绍了信号源的硬件和软件设计,以及50 Hz陷波器的设计,并给出了该方法的整体实现。实验证明,该方法在电容电流的测量中具有准确、方便、安全等特点。     

海外工程中水轮发电机介损和电容测量试验

在大型汽轮、水轮发电机等大电容设备的测量和检修过程中,常因测量仪器容量不够,而无法适应海外工程特点和满足国内外标准要求。针对此问题,首先分析了串联谐振装置和介质损耗（介损）测量装置的应用原理,然后根据其测量特性,提出了组合应用串联谐振装置和介损测试仪进行水轮发电机介损和电容测量。将该方法应用到印度尼西亚总承包工程的测量试验中,根据国内外标准分析了试验结果。试验研究表明,该方法测量准确、方便,并且试验结果达到了国际标准。