纳米碳纤维水泥基材料的电容抗效应

研究了烘干与氯盐溶液浸泡条件下不同掺量纳米碳纤维导电水泥基材料的电容抗效应,主要考虑交流电频率、纳米碳纤维掺和电极安装方式的影响。结果表明:在干燥状态下,导电水泥石电容值随着纳米碳纤维掺量的提高而增大,随着交流电频率的增大而下降。当碳纳米纤维掺量低于2.5%时,浸泡氯化钠溶液使导电水泥石的电容显著增加,粘贴式电极的电容值大于埋入式电极试件;当纤维掺量高于2.5%时,浸泡氯化钠溶液和电极安装方式对电容值的影响不大。

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。

“X7R抗还原片式电容器介质材料”通过成果鉴定

华南理工大学材料学院卢振亚副教授课题组和广东风华高新科技集团公司共同承担的广东省“十五”重大科技专项项目“片式电容用抗还原介质瓷料的研制”于2004年9月26日通过了由广东省科技厅组织并主持的“X7R抗还原片式电容器介质材料”科技成果鉴定．

一种小电容检测方法——充放电法

简要介绍传统及现有小电容测量方法的优缺点,其中包括谐振法、振荡法(RC振荡法和LC振荡法)、交流电桥法;重点给出了一种可抗寄生电容干扰的充放电法,阐述了此方法的基本原理,分析了其电路模型、传递函数、灵敏度并给出了实验系统原理框图,结合实际应用给出电路中器件及参数的选取原则,并得出了实验结论.该电路具有抗寄生电容干扰强、灵敏度高、容易实现、成本低等优点.

一种用于电容式PT系统的微小电容量检测方法

针对大型工业过程设备（如大型反应器，大型容器及大型分离器等）使用电容式ＰＴ技术中存在的微小电容量检测问题，提出了使用高压交流单边激励与磁性Ｃ／Ｖ变换相结合的方法进行测量．该法具有较强的抗杂散电容的能力．实验表明，该法的电容测量分辨率可达０１ｆＦ数量级．

基于传感器阵列的油品分层系统的研究与设计

针对目前油品含水率测量存在的油污的问题,设计了6电极电容传感器阵列,以此来解决单个或少量传感器探头易被油污污染,严重影响决策判断的问题.针对电路中漏电流问题进行了电路的改进,采用D触发器来控制两个互补时序的开关,比单纯用非门的方法能减少大概几十纳秒的电荷泄漏时间,能较好的改善漏电流的问题.设计了基于PC机WINDOWS操作系统的实验数据采集与分析系统,试验证明所设计的传感器阵列与数据采集系统能够达到预期的简单液体层次分离的效果.

A320系列飞机引气渗漏探测线故障排除的新方法

空客A320系列飞机机翼引气渗漏探测线故障为多发性故障。针对探测线长、分段多、不易接近等情况,本文给出了新的检测排故方案,通过检查探测线的阻抗,快速定位故障探测线,从而节省排故时间和人力。

Universal lithiophilic interfacial layers towards dendrite-free lithium anodes for solid-state lithium-metal batteries

Solid-state lithium-metal-batteries(SSLMBs)using garnet Li_(6.4)La_(3)Zr_(1.4)Ta_(0.6)O_(12)(LLZTO)as the solid electrolyte are expected to conquer the safety concerns of high energy Li batteries with organic liquid electrolytes owing to its nonflammable nature and good mechanical strength.However,the poor interfacial contact between the Li anode and LLZTO greatly restrains the practical applications of the electrolyte,because large polarization,dendritic Li formation and penetration can occur at the interfaces.Here,an effective method is proposed to improve the wettability of the LLZTO toward lithium and reduce the interfacial resistance by engineering universal lithiophilic interfacial layers.Thanks to the in-situ formed lithiophilic and ionic conductive Co/Li_(2)O interlayers,the symmetric Li/CoO-LLZTO/Li batteries present much smaller overpotential,ultra-low areal specific resistance(ASR,12.3 X cm^(2)),high critical current density(CCD,1.1 mA cm^(-2)),and outstanding cycling performance(1696 h at a current density of 0.3 mA cm^(-2))at 25℃.Besides,the solid-state Li/CoO-LLZTO/LFP cells deliver an excellent electrochemical performance with a high coulombic efficiency of~100%and a long cycling time over 185 times.Surprisingly,the high-voltage(4.6 V)solid state Li/CoO-LLZTO/Li_(1.4)Mn_(0.6)Ni_(0.2)Co_(0.2)O_(2.4)(LMNC622)batteries can also realize an ultra-high specific capacity(232.5 mAh g-1)under 0.1 C at 25℃.This work paves an effective way for practical applications of the dendrite-free SSLMBs.

Electrochemical properties of Co-S/x wt.% AB_5 composite materials

The Co-S/x wt.% AB5 （x=0, 10, 20, 30） composite materials were prepared by simply mixing Co-S material fabricated by hy- drothermal method and AB5 alloy. The structure and morphology of the composite materials were characterized by XRD and SEM, respectively. The electrochemical properties of the composite electrodes were studied by the galvanostatic charge, dis- charge test and electrochemical impedance spectroscopy. The results showed that the Co-S/20 wt.% AB5 composite electrode showed the highest discharge capacity and the best cycling stability. The existence of the AB5 alloy improved the electro- chemical activity of composite electrodes, reduced the electrochemical polarization resistances and promoted the electrochem- ical conversion reaction between Co and Co（OH）2. In order to improve the utilization rate of active materials, 0.0! mol/L Na2S203 was added into the electrolyte. The electrochemical properties of the composite electrode were significantly enhanced. After fifty cycles, the discharge capacity of the composite electrode increased from 407 to 481.7 mAh/g and the capacity reten- tion increased from 79.7% to 91.2%.

Fault component integrated impedance-based pilot protection scheme for EHV/UHV transmission line with thyristor controlled series capacitor(TCSC) and controllable shunt reactor(CSR)

This paper analyzes the fundamental frequency impedance presents a novel transmission line pilot protection scheme characteristic of a thyristor controlled series capacitor （TCSC） and based on fault component integrated impedance （FCII） calculated for a transmission line with TCSC and controllable shunt reactor （CSR）. The FCII is defined as the ratio of the sum of the fault component voltage phasors of a transmission line with TCSC and CSR to the sum of the fault component current phasors where all the phasors are determined at both line＇s terminals. It can be used to distinguish internal faults occurring on the line from external ones. If the fault is an external one the FCII reflects the line＇s capacitive impedance and has large value. If the fault is an internal one on the line the FCII reflects the impedance of the equivalent system and the line and is relatively small. The new pilot protection scheme can be easily set and has the fault phase selection ability and also it is not affected by the capacitive current and the fault transition resistance. It is not sensitive to compensation level and dynamics of TCSC and CSR. The effectiveness of the new scheme is validated against data obtained in ATP simulations and Northwest China 750 kV Project.

视频技术

0009894电容过程成像技术的进展〔刊〕/王化祥//仪器仪表学报.—2000,21(1).—4～7,11(E)本文详细介绍了电容过程成像技术的新进展,其中包括阵列式敏感电极结构设计,具有抗杂散电容影响的高灵敏 AC 桥电容检测线路以及 Landweber 迭代算法再构图像,从而使成像系统性能指标明显得到改善。