超声波酸洗在镍电解系统中的应用

为了在镍电解精练过程中去除导电棒表面的污垢和氧化物设计了一种超声波酸洗系统,该系统使用了超声波装置和一定浓度的酸液,可以将导电棒表面清洗干净,保证了导电棒除污后使用的效果和电解时产品的质量.并且整个过程实现了自动化.     

电解铜导电棒矫直机的研究

电解铜导电棒在电铜生产中广泛使用,由于变形而影响在机组的移送和槽内导电率,严重的只能报废,经济损失较大。通过矫直机对变形的导电棒矫直,使之重复利用,降低生产成本,效益显著,在铜电解行业具有推广价值。     

窄细槽分段速进给电解加工方法研究

针对小间隙电解加工过程中极间间隙不稳定导致加工效率低下甚至发生短路等问题,以窄细槽电解加工过程为研究对象,提出自适应于工件蚀除速度的电极进给分段速加工方法。建立极间电流与加工深度之间的理论关系模型,采用单因素实验法对理论模型进行修正,使其反映实际加工过程。依据电解过程中深度与电流的变化规律,建立电极进给速度实时修正方程,实现电解过程不同进给速度段的划分。采用速度线性矢量混合算法,构建速度控制方程,实现各段速间的平稳过渡,保证电极进给速度变化时极间电流的稳定。实验结果表明,分段速进给控制方法能有效避免小间隙电解过程中由于进给速度与工件蚀除速度不匹配而导致的短路现象,有效保证窄细槽电解加工效率与轮廓精度。     

用于铝电解电流精确测量的手持式光纤电流传感器研究

电流强度是电解铝工艺的基本参数,精确测量电解槽分布电流可提高铝电解生产效率和工作稳定性。 本文分析了光纤 电流传感器相比于传统电流测量技术在电解槽电流测量中的原理性优势,针对目前光纤电流传感器在现场应用中存在的重复 拆装和大电流条件下温度误差问题,创新提出了基于柔性封装的传感光纤插接方案和温度误差与非线性误差二维补偿技术,首 次设计研制了手持式光纤电流传感器,测试结果表明:传感器的重复拆装误差小于 0. 12% ,在-40℃ ~ 70℃ 温度范围内测量 0. 5~ 30 kA 电流时的误差小于 0. 2% ,在某电解槽现场测量立柱母线电流时与控制室显示值的误差小于 0. 4% ,并通过对阴极钢 棒分布电流的连续监测和分析,实现了电解槽破损的提前预警。     

城市轨道交通直流馈线电缆在线监测方案设计与应用

在城市轨道交通供电系统中,直流馈线电缆若持续存在电流泄漏,可能会烧坏电缆,甚至发生短路故障.设计了一种测量直流馈线电缆泄漏电流的方案,通过将霍尔元件嵌套在馈线柜的出线电缆,利用霍尔元件采集数据,并通过录波装置借由交换机连接到无线路由器,把采集到的数据实时上传到云服务器,通过网页端进行数据的访问及处理分析.该方案已经成功应用于广州地铁一号线坑口车辆段,经过运行及测试,在线监测系统运行稳定,具有良好的监测效果.     

微细电解加工的过程检测及精度控制

超短脉冲微细电解加工时,极间加工间隙很小,加工过程的稳定性是影响加工精度的重要因素。在所建立的加工控制系统中,采用两步短路对刀法精确定位电极初始间隙,利用霍尔电流传感器实时检测平均加工电流,动态控制电极的进给运动速度,从而保持不同加工条件下稳定加工的最小加工间隙。进行了微细结构的电解加工试验,通过检测加工过程的状态,保证了加工的稳定性,实现了线宽只有25μm的微细结构加工。     

基于重力加速度传感器的三维高斯计的设计

文中采用3个线性霍尔元件THS119、加速度传感器芯片ADXL345和单片机测量系统实现了空间静态三维磁感应强度的测量。4个芯片紧凑地贴在探头相互正交的4个平面上,依据重力加速度坐标对磁感应强度坐标进行修正。数据采集电路为探头提供工作电流,完成数据采集并实现与计算机的通信。计算机显示程序使用Lab VIEW图形化编程语言编写,用于显示磁感应强度的大小、三维分量、方向角和三维空间取向图。     

非正弦波中频强磁场测量方法及装置

用规格为A1323LUA的霍尔元件作为磁信号转换器、AD637作为真有效值集成转换器构建了霍尔传感器测量电路及信号处理电路,再组合其它功能模块,以真有效值代替平均值算法,在实验室自制了可以测量不同电流波形磁场的测量装置,通过对磁感应强度计的定标及测量验证,能满足非正弦波中频磁场强度的检测需要。     

双层实心异步磁力联轴器三维静态气隙磁场解析计算

为了得到双层实心异步磁力联轴器三维静态气隙磁场的空间分布,首先运用等效电流法建立了联轴器气隙磁场的三维解析模型,推导了气隙内任意一点磁感应强度的解析表达式。然后针对一台14极磁力联轴器样机,采用MATLAB软件编程求解得到了气隙平均半径处径向、周向及轴向磁感应强度的空间分布情况,结果表明径向磁感应强度解析值在-0.36T～0.36T之间变化,周向磁感应强度解析值在-0.6T～0.6T之间变化,轴向磁感应强度解析值在-0.35T～0.35T之间变化。最后采用实验装置对三维静态气隙磁场进行了测量测量结果与解析结果具有很好的一致性证明了解析法的正确性。     

测量电流速度方法的研究

主要研究如何精确地测量电流在金属导线中的传输速度。根据速度等于长度除以时间的原理,讨论了如何通过测量电流流过导线的时间的方法来测量电流速度;同时提出了减小测量误差的方法。通过软件仿真及实验测试,测得电流在导线中的传输速度大约是297619 km/s,比光速略小。该方法原理简单,测量结果比较准确。     

Development of standard test methods for evaluating defibrillation recovery characteristics of disposable ECG electrodes

A clinically relevant test for the measurement of defibrillation overload recovery of prefilled disposable ECG electrodes was developed and is proposed for use in an ECG electrode standard under development by AAMI. Defibrillation overload voltages and currents, as well as electrode polarization recovery voltages, were first measured in animal tests on 12 types of electrodes to allow correlation with various bench tests using a capacitor discharge at 10, 200, or 1000 V. Current overloads absorbed by the electrodes under worst conditions in animal tests were in the range of 2 percent of the defibrillation current flowing through the chest. These overloads were absorbed by most Ag-AgCl electrodes without excessive polarization. However, stainless steel, brass, and tin electrodes tended to polarize to levels that would saturate many ECG monitors. A standard bench test using a 200-V 10-muF capacitor was recommended for inclusion in the AAMI standard to determine whether electrodes are acceptable for use during defibrillation.     

Arc development of triggered vacuum switch with multi-rod electrode system

Triggered vacuum switch (TVS) is one of the important switch apparatuses in the high pulsed power system, which takes the vacuum as insulation and arc-extinguishing medium of main gap. The conduction of TVS is the arcing process of vacuum arc in practice. So, it is meaningful to research on the vacuum arc characteristics for the high current application of TVS. A six-gap rod electrode system is studied in this paper. It is made up of 3 pairs of rod electrodes, i.e., spatially interleaved rods of opposite polarity on a ring. The arc development under different high currents is tested and discussed, based on the electrical characteristics of the vacuum arc voltage and arc resistance. The variety of arc voltage shows the parallel arcing and the transfer process in the multi-channel, which is benefit to maintain the diffusion of vacuum arc. A TVS sample based on multi-rod electrode has carried high current of 225 kA in peak and charge transfer of 45 C in a pulse.     

Improved analysis techniques for cylindrical and spherical double probes

A versatile double Langmuir probe technique has been developed by incorporating analytical fits to Laframboise's numerical results for ion current collection by biased electrodes of various sizes relative to the local electron Debye length. Application of these fits to the double probe circuit has produced a set of coupled equations that express the potential of each electrode relative to the plasma potential as well as the resulting probe current as a function of applied probe voltage. These equations can be readily solved via standard numerical techniques in order to determine electron temperature and plasma density from probe current and voltage measurements. Because this method self-consistently accounts for the effects of sheath expansion, it can be readily applied to plasmas with a wide range of densities and low ion temperature (T(i)∕T(e) ? 1) without requiring probe dimensions to be asymptotically large or small with respect to the electron Debye length. The presented approach has been successfully applied to experimental measurements obtained in the plume of a low-power Hall thruster, which produced a quasineutral, flowing xenon plasma during operation at 200 W on xenon. The measured plasma densities and electron temperatures were in the range of 1 × 10(12)-1 × 10(17) m(-3) and 0.5-5.0 eV, respectively. The estimated measurement uncertainty is +6%∕-34% in density and +∕-30% in electron temperature.     

霍尔效应式点焊焊接电流的测量

论述霍尔效应式点焊焊接电流的测量方法。由于焊接电流波形失真比较大，所以选用集成真有效值交直流电压转换器，该转换器抗波形畸变能力强。并且提出了对霍尔元件、放大器和电阻选择的方法。     

铌酸锂集成 MZI 型光波导大电流传感器

采用集成光学技术,设计与研制出了一种用于大电流测量的集成光波导电流传感器,器件体积为 78 mm×18 mm×9 mm。 对带有多环形天线和调制电极的传感器结构进行了理论分析,并利用 COMSOL Multiphysics 软件建立传感器的三维模型,仿真 验证了所设计的传感器可用于脉冲大电流的测量。 搭建了脉冲大电流测量实验系统,对传感器性能进行测试。 结果表明,传感 器测量得到的脉冲电流时域波形与 Pearson 电流互感器测量得到的脉冲电流时域波形相比,波前时间 Tf 和持续时间 Td 的平均 相对误差分别为 3. 977 5% 和 5. 437 5% 。 传感器在 100 ~ 3 300 A 的被测电流范围内,线性相关系数为 0. 998 97,当信噪比为 6 dB 时,传感器最小可测电流为 66 A。     

超薄液膜厚度测量技术研究

本文研究出了一种超薄液膜厚度的测量技术,利用该项技术可以方便地测量出微米量级的超薄液膜厚度。文中论述了采用电阻法测量超薄液膜厚度的基本原理,解决了传感器设计与制造,测量电路设计,标定装置制做和实验方法等一系列技术问题。本文的工作为火箭发动机,燃气轮机,柴油机,锅炉,以及其他动力机械中的液体燃料在燃烧室壁面上形成的超薄液膜的蒸发过程研究提供了一项新的测试手段。     

测量电炉变压器二次侧电流的研究

以鄂尔多斯双欣化工密闭电石炉电极电流为研究对象。由于一次侧电流和变压器变比估算二次侧电流，测量数据难以精确。根据电极电流测量精度的要求，通过变压器运行机理分析和电流交换器的性质设计推导出一种方法。该方法自运行以来稳定、可靠、操作简单，有效提高了工作效率。     

电容耦合非接触电极及心电信号获取

电极与皮肤间接触所导致的不适感,是穿戴式心电信号测量系统实际应用中的常见问题。设计了一种非接触心电信号测量系统。采用印刷电路板制作的测量电极,借助电容耦合测量位移电流的方式获取心电信号。采用反接二极管提供测量所需的高阻值偏置电阻,结合高输入阻抗仪表放大器,制作了测量电极信号提取电路。测量系统由两个测量电极与一个直接与测量电路地相连的参考电极组成。选择金属铝板、导电纤维和导电橡胶作为参考电极,实验研究了共模干扰抑制性能与参考电极接触阻抗之间的量化关系。将主元分析与奇异谱分析相结合,提出了一种心电信号处理算法。实验结果表明,该系统可在棉质线衣外侧有效获得满意的心电信号。     

Note: Human heartbeat measurement on the basis of current generated by electrostatic induction

In this study, we developed an effective nonattached, noncontact technique for measurement of the human heartbeat. This method detects the human heartbeat by measuring the current generated by variations in the capacitance between a given electrode and the human body. An electrode is placed a few centimeters from the subject's chest, and the electrostatic induction current (on the order of picoamperes) flowing through the electrode is then detected. We propose an occurrence model for the electrostatic induction current generated by variations in the electrostatic capacitance generated because of the human heartbeat, with respect to a given measurement electrode. Furthermore, we compared waveforms of the human heartbeat simultaneously obtained by using conventional electrocardiography (ECG) and our proposed electrostatic induction method. The waveform obtained using the proposed method had the same cycle as that obtained using conventional ECG. This confirms that we can detect the human heartbeat under nonattached, noncontact conditions.     

Airflow produced by dielectric barrier discharge between asymmetric parallel rod electrodes

We observed a novel type of airflow produced by an atmospheric rf discharge between asymmetric parallel rod electrodes. The electrodes were a bare metal rod 1 mm in diameter and a glass-coated metal rod 3.2 mm in diameter. The thrust, measured by a pendulum, increased with discharge input power.