电容传感器在使用中存在的几个问题及处理方法

随着电容测量技术的迅速发展，电容传感器在非电量测量和自动检测中得到广泛应用，但它在使用过程中也存在一些问题，针对在使用电容传感器过程中存在的几个问题，从电容传感器的原理和工作过程两个方面进行了讨论，并提出行之有效的处理方法。     

低压铝箔交流腐蚀研究

在３０Ｈｚ频率下，通过铝箔在ＨＣｌ＋Ｈ２ＳＯ４＋ＨＮＯ３＋Ｈ３ＰＯ４体系中的交流腐蚀，研究腐蚀液组成中腐蚀主体及缓蚀剂对铝箔腐蚀的作用，探讨腐蚀过程中电源频率、腐蚀液温度、电流密度及腐蚀时间对铝箔腐蚀的影响。腐蚀液组成的配比恰当，有利于比容的提高。在特定的频率下采用合适的腐蚀液温度、适宜的电流密度和腐蚀时间可以提高铝箔的静电容量。     

电容位移法精确测量磁性薄膜的磁致伸缩系数

介绍了一种精确测量磁性薄膜磁致伸缩系数方法－电容位移法，并自行研制组装了一套测量装置，通过误差分析，仪器的精确标定，对稀土－铁超磁致伸缩薄膜的磁致伸缩系数进行了测量，获得满意的结果。     

Electrochemical properties of ultra-long,aligned, carbon nanotube array electrode in organic electrolyte

The electrochemical properties of an electrochemical double-layer capacitor electrode based on an ultra-long (500 μm), aligned, carbon nanotube array (ACNTA) in Et₄NPF₆/propylene carbonate electrolyte are examined. The specific capacitance of the ACNTA electrode in an organic electrolyte is 24.5 F g⁻¹, which is larger than that obtained in an aqueous electrolyte. The results of ac impedance measurements show that the ACNTA electrode gives a high power density and an excellent rate capability in an organic electrolyte. It is shown that the ACNTA electrode has a lower equivalent series resistance and a better rate capability than activated carbon electrode. This is due to the fact that ACNTA possesses a larger pore size and a more a regular pore structure. Both these features are conformed by scanning electron microscopic and nitrogen gas adsorption studies.     

基于电容层析成像和模糊模式识别的油气两相流流型辨识新方法的研究

基于电容层析成像和模糊模式识别技术别提出了一种油气两相流流型辨识的新方法。建立了12电极电容层析成像流型自动识别系统，该系统利用Tikhonov正则化原理并结合SIRT(Simultaneous Reconstruction Techniques)算法进行图像重建。Tikhonov正则化原理用于克服图像重建过程中的不适定问题，SIRT算法用于提高最终重建图像的质量。根据流型的随机和模糊特性，提出了一种根据管截面重建图像进行流型辨识的模糊流型判别方法。研究结果表明，提出的流型辨识新方法是有效的。对于层状流、核心流、环状流、均相流等流型，流型辨识的准确率高于95％，辨识一个流型所用的时间小于0.3秒。对于塞状流，流型辨识的准确率高于90％。     

自适应天线匹配低频RFID读写器设计

在工业现场、野外甚至水中,RFID读写器天线电特性参数将发生改变,导致阻抗不匹配和发射功率大幅下降,最终降低RFID读写器读写范围和效率。为了解决这个问题,构建了一个自适应天线匹配RFID读写器系统,该系统在基本读写器系统上增加了自适应电容匹配矩阵、正弦波均方根检测和模/数转换器。该系统通过依次配置电容矩阵,扫描天线发射信号幅度,检测出最佳匹配电容,实现天线阻抗的最佳匹配。通过实验表明,在一定范围内该系统能够实现自动的阻抗匹配,获取最大发射功率。     

基于Matlab和电容感应的室内定位系统

提出了一种基于Matlab和电容感应的室内三维定位系统的设计方法。该系统主要由三维电容极板、电容采集模块、信号频率采集模块、实时串口通信模块、Matlab显示模块等组成。系统依据电容感应原理,通过测量监测区域三维电容基板之间电容值的变化量,换算出被测物体相对极板的距离,并通过Matlab图像显示窗口显示被测物体对应的三维位置。该室内定位系统特别适用于对进入监测区域的活动物体进行实时定位监测。     

平行梁式电容传感器力学性能的仿真与分析

针对S型平行梁式电容称重传感器参数结构设计问题,运用有限元软件ANSYS Workbench对平行梁式弹性体结构进行参数化模拟仿真,基于二次多项式曲面拟合建立其结构力学性能与主要结构参数的函数关系,并通过算例分析验证了拟合公式的有效性。研究表明,拟合公式对复杂仿真计算后的结果有很好的近似,能更好的反应实际情况,公式结构更加简洁,具有较快的收敛速度、较高的精度和较好的推广能力,有利于准确实现平行梁式电容称重传感器结构参数设计。     

Electrochemical capacitance of well-coated single-walled carbon nanotube with polyaniline composites

Well-coated single-walled carbon nanotube (SWNT) with polyaniline (PANI) composite electrodes with good uniformity for electrochemical capacitors are prepared by the polymerization of aniline containing well-dissolved SWNTs. The capacitance properties are investigated with cyclic voltammetry, charge-discharge tests and ac impedance spectroscopy. The composite electrode shows much higher specific capacitance, better power characteristics and is more promising for application in capacitor than pure PANI electrode. The effect and role of SWNT in the composite electrode are also discussed in detail.     

A novel high power symmetric ZnO/carbon aerogel composite electrode for electrochemical supercapacitor

We present, for the first time, a new material of symmetric electrochemical supercapacitor in which zinc oxide (ZnO) with carbon aerogel (CA) was used as active material. Physical properties of ZnO/CA composite were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). It was found that ZnO has single hexagonal structure and the grain size increases with increase of ZnO compository. The result of cyclic voltammetry indicates that the specific capacitance of ZnO/CA composite in 6 M KOH electrolyte was approximately 25 F/g at 10 mV/s for 2:1 composition. AC impedance analysis reveals that ZnO with carbon aerogel powder enhanced the conductivity by reducing the internal resistance. Galvanostatic charge/discharge measurements were done at various current densities, namely 25, 50, 75, and 100 mA/cm². It was found that the cells have excellent electrochemical reversibility and capacitive characteristics in KOH electrolyte. The maximum capacitance of the ZnO/CA supercapacitor was 500 F/g at 100 mA/cm². It has been observed that the specific capacitance is constant up to 500 cycles at all current densities, which implies that the dendrite formation was controlled.