Measurement of T&T olfactometer standard odors using quartz resonator gas sensors

T&T olfactometer standard odors for measuring olfactory sense seem to be suitable standard odorants for use in comparing sensor response with human perception. The responses of quartz resonator sensors covered with synthetic lipid membrane to five odors supplied with the T&T olfactometer were evaluated. The five odorants were not individually distinguishable from the response patterns, because the sensors had low sensitivity for the five odorants. The five odorants were discriminated after applying principal component analysis to the response data. Comfort or discomfort feelings regarding five odors were successfully distinguished with the responses of three sensors and principal component analysis. New sensors coated with urethane resins were demonstrated and found to be promising candidates for use as sensors with high sensitivity for the T&T olfactometer. © 1997 Scripta Technica, Inc. Electr Eng Jpn, 120(1): 49–54, 1997     

兼具开路故障诊断能力的MMC电容电压测量方法

模块化多电平换流器在高电压等级、大输送容量场合的应用中,各桥臂大量子模块的电压需要实时采集并维持在允许范围内,但电压传感器配置数量的增加影响了系统的经济性与可靠性。为解决以上问题,提出了一种基于电容电压预估和组电压测量的子模块电容电压测量方法。该方法对桥臂子模块进行了分组,每组仅配备一个电压传感器,从而使传感器数量得以减少。在该测量方法基础上提出了一种子模块开路故障诊断策略,通过比较电压实测值与预估值完成开路故障的快速诊断,并且对传感器设置了故障冗余,在传感器发生故障的情况下系统仍能保持稳定运行。基于PSCAD/EMTDC搭建了21电平基于模块化多电平换流器的高压直流仿真系统。仿真结果表明,所述方法具有与传统方法近似的测量精度,同时能在较短时间内诊断子模块开路故障与传感器故障。     

高频局放传感器性能检测关键点研究与验证

针对高频局放传感器的性能检测,根据高频传感器工作原理,梳理出了传感器的关键性能参数,依托比对检验平台,对不同厂家主流传感器的性能进行检测,分析传输阻抗和频带宽度测试曲线,得出高频传感器的性能检测关键考核点,结果表明只有一家综合性能符合要求。     

Sensors based on saw resonator with “nontraditional formats” of output signal

It is demonstrated that the sensitivity of sensors based on two-port surface acoustic waves (SAW) resonators increases by a factor of Q (Q-loaded quality factor of the resonator) if the output signal of these sensors is represented in the phase format instead of the conventional frequency format. Practical possibility of use of the SAW gas sensor with phase format of transmitted signal as output signal is demonstrated using procedure of the determination of the water contents in gaseous nitrogen with 386 MHz ST-quartz SAW resonator as an example. It is found that the SAW power affects the sensor response owing to the influence of the SAW intensity on the equilibrium amount of water molecules adsorbed on the resonator surface. Extremely high sensor sensitivity was obtained when using phase format of reflected signal as a sensor output. Using such a format of sensor output we have reliably measured the change of temperature of ST-quartz SAW sensor substrate as small as 0.01^∘C.     

柔性电容式触觉传感器的研究与实验

类似"人工皮肤"的触觉传感器在人工智能、医疗器械等领域有着广泛的应用。利用柔性电路板加工工艺设计了一种基于分布电容的触觉传感器,并分析了其工作原理。设计的触觉传感器主要由3层膜结构压制而成,包括上层电极层、中间间隔层和下层电极层,并在每一触元上表面粘贴一硅胶触点以增大灵敏度。针对柔性电路板的不同形式和间隔层不同厚度,加工了9种不同参数的触觉传感器,并对这9种传感器进行了量程、灵敏度、线性度等实验对比。实验证明,通过这2个参数的选择可以获得不同量程和灵敏度的触觉传感器,可根据实际应用场合选择具体参数以满足应用需求。同时阵列扫描实验证明设计的触觉传感器可以获得其表面的受力情况,并可以将触觉力在上位机上可视化的显示出来。     

磁传感器阵列测量大电流的传感器拓扑问题研究

磁传感器阵列通常以非接触方式安放在多导体系统的周围空间用来测量电流。为研究磁传感器阵列拓扑而引起的理论误差,基于离散傅里叶变换（DFT）的电流测量算法,建立了以求解系数矩阵条件数最小值为目标函数的磁传感器阵列拓扑优化模型,并提出了若干优化约束条件。该数学模型可以同时适用于交流和直流的多母排平行导体系统测量大电流。最后,以三相电流测量系统磁传感器拓扑的优化问题为例给出了求解步骤,MATLAB仿真与实验结果验证了优化数学模型的有效性。     

一种在线分析变压器故障特征气体的智能传感器

在线监测变压器油中溶解气体可有效地分析变压器绝缘状况,在线监测用气体传感器是实施该技术的关键。针对半导体气体传感器的交叉敏感特性,提出了将气体传感器阵列与人工神经网络技术相结合,利用6个半导体气体传感器组成传感器阵列,采用BP神经网络进行模式识别。大量的试验证明,所提出的智能传感器可有效地提高H2,CO,CH4,C2H4,C2H2,C2H66种气体的分辨率和检测灵敏度。     

Development of a fibre-optic sensor for partial discharges in oil-filled power transformers

Determination of partial discharge locations in large oil-filled power transformers is unreliable and difficult using external acoustic sensors, and internal sensors would need to be non-metallic. Thus the use of a fibre-optic coil as an acoustic sensor would allow the detection and location of partial discharges with potentially a much greater sensitivity. This paper describes the design of such a sensor and its signal processing requirements, its construction and its initial testing. The sensor was found to be able to detect 1-Pa acoustic pressure waves under optimum conditions; and to detect partial discharges in small artificial voids in an oil-bath.     

基于无线传感器网络的高压输电线监测系统研究

将无线传感器网络技术应用于高压输电线路的监测系统中,通过环境传感器采集线路的应力、温度和震动等环境信息,实现高压输电线路实时环境量监测,并结合微型摄像机实现对异物侵入、违章作业、人为偷盗的远程视频监测及录像;设计了高压输电线上传感器节点的组网模式,通过遗传算法优化传感器节点的运行模式,在满足系统特定信息采集功能及网络连通性的前提下,有效地实现了网络负载的均衡配置,优化了网络的能量管理。     

特高压气体绝缘开关设备中特快速瞬态过电压测量用电容传感器的标定

为保证特高压气体绝缘开关设备（gas insulatedswitchgear,GIS）中特快速瞬态过电压（very fast transientovervoltage,VFTO）测量用手孔式电容传感器的准确性,必须对其进行标定。研制了用于电容传感器的标定系统,它由3种不同幅值及波形的脉冲源及相应测量系统组成。其中：低电压陡脉冲源用于校验电容传感器的高频特性;高电压陡脉冲源用于校验传感器在高压下的稳定性;低电压长波尾电源用于校验传感器的低频特性。水电阻分压器及金属膜电阻分压器用于测量3种脉冲源的输出波形,在标定电容分压器前,对电阻分压器的频率特性及线性度特性进行了试验。电容传感器的标定试验结果表明,华北电力大学和清华大学研制的电容传感器均具有良好的频率特性、线性度和稳定性,可以满足特高压GIS设备VFTO测量工作的需要。     

Development of Corrosion‐Resistant Pressure Sensor with Semiconductor Strain Sensor

In automotive and industrial fields, pressure sensors are a key component for precisely controlling the mechanical systems. Conventional micro electro mechanical system (MEMS)‐based pressure sensors have an advantage in noise resistance, because both strain gauges and control circuits are integrated in one chip. However, the MEMS‐based pressure sensors are generally fabricated on an Si substrate, and have a low stability against various active gases. Thus, we have newly proposed a pressure sensor which consists of an Si‐based strain sensor set on a stainless steel diaphragm with a high stability against the active gases. The key technology is that a Koval plate is inserted between the strain sensor and the stainless steel diaphragm, for preventing the breakage or the delamination of the strain sensor at the bonding interface due to a difference in thermal expansion. Structure of the sensor including the shape and the size of Koval plate and the assembly position of the strain sensor were designed using structural simulation and experiments. Eventually, the 2.8 mm wide and 0.17 mm thick Koval beam was bridged on the stainless steel diaphragm for efficiently transmitting the diaphragm deformation to the strain sensor. The strain sensor was assembled at the edge of Koval beam with a glass bonding technique. Consequently, the developed pressure sensor has achieved a small dispersion of less than 1% F. S. in a temperature range from 0 °C to 85 °C.     

Characteristics of fabricated catalytic combustible micro gas sensor with low power consumption for detecting methane leakage of compressed natural gas bus

For keeping the safety of compressed natural gas-powered buses (CNG, CH₄), a small sized and low power consumption gas sensor is needed for the fuel leakage alarm system. So catalytic combustible micro gas sensors were designed and fabricated by microelectromechanical systems (MEMS) technology and the sensors were measured output voltage potential of the sensor circuit as sensitivities to methane. The sensor was consisted of a sensing platform and a compensation platform, and the length and width of the fabricated platform were 3 mm by 3 mm. The output voltage of a fabricated micro sensor were 0.727 mV, 0.548 mV, 0.45 mV, and 0.29 mV at methane concentrations of 4,630 ppm, 3,473 ppm, 2,315 ppm, and 1,158 ppm respectively, at the input power of 104 mW. Fabricated micro gas sensors could be operated at low power consumption and showed good selectivity. For further study, the long-term stability of micro sensors will be done before applying to CNG powered buses.     

Surface acoustic wave sensors to detect volatile gases by measuring output phase shift

This paper presents properties of saw acoustic wave (SAW) gas sensors to detect volatile gases such as acetone, methanol, and ethanol by measuring phase shift. A dual-delay-line saw sensors with a center frequency of 100 MHz were fabricated on 128^∘ Y-Z LiNbO₃ piezoelectric substrate. In order to improve sensitivity of SAW sensors, a thin titanium (Ti) film as mass sensitive layer was deposited using e-beam evaporation on the surface of the SAW sensors. In our investigation the response time and sensitivity of SAW sensors were measured. The response time and sensitivity of SAW sensor with thin Ti film were strongly improved because of changing electrical and mechanical properties in the mass sensitive layer. As a result, high sensitivity and fast response time could be achieved by deposition of thin Ti film as mass sensitive layer on the surface of SAW sensor. It can be applied for high performance electronic nose system by assembling an array of different sensors.     

Accurate voltage measurement with electric field sampling usingpermittivity-shielding

This paper introduces permittivity-shielding which enables the measurement of voltage with very few electric field sensors. Voltage sensor designs using permittivity-shielding can exploit existing optical sensor technology without the need for the expensive and potentially hazardous insulation found in many modern optical voltage transducers (OVTs). Numerical simulations demonstrate that a voltage sensor consisting of 100 MΩ shielding and six electric field sensors, or less, mounted inside an "off-the-shelf" stand-off insulator can achieve IEC 60044-2 0.2 metering class accuracies (<0.2% magnitude error and <10 minutes phase error) even in the presence of strong stray field effects     

IR detectors using Pb(Mg1/3Nb2/3)O3 and Pb(Sc1/2Ta1/2)O3 ceramics under DC bias

Recently, one type of thermal-type IR detector, the pyroelectric sensor, has become of great interest in commercial applications, because of its ability to operate without cooling, its constant detectivity independent of wavelength, and its low cost. The conventional pyroelectric materials are usually normal ferroelectric materials with a first and second phase transition. The working temperatures are sufficiently below the Curie temperature T_c for stable responsivity to temperature. Electric field induced-type pyroelectric sensors have also been proposed. Relaxor ferroelectric materials such as Pb(Mg_1/3Nb_2/3)O₃ (PMN) and Pb(Sc_1/2Ta_1/2)O₃ (PST), which have a glassy Curie temperature near room temperature, are used in this type of sensor. This paper describes the sensor properties of electric field induced-type pyroelectric sensors prepared by using PMN and PST ceramics as compared with the conventional type sensors. Material evaluations of PMN and PST ceramics were made to determine their dielectric and pyroelectric properties. PMN shows excellent induced pyroelectric properties for the sensors over a wide range of temperatures. On the other hand, PST seems to be inadequate for an IR detector because of a very narrow high-response temperature range. The sensors with PMN and PST ceramics show enhanced pyroelectric activities under dc bias field. The measured sensor voltage responsivities agree with the calculated values for the PMN case. The electric field induced-type infrared sensor with thick or thin film materials seems to be satisfactory as linear array IR detectors for thermal imaging, with application of a higher electric field.     

碳纳米管传感器检测SF6放电分解组分的实验研究

研制了一种用浓硫酸和浓硝酸修饰,以印制电路板为基底,用于检测SF6局部放电分解组分的碳纳米管传感器。分析了碳纳米管膜的导电模型,并通过真空下传感器的温度特性试验,对修饰前后的碳纳米管传感器的电阻随温度变化的关系进行了分析。在实验室采用SF6放电分解试验装置,用碳纳米管传感器对分解组分进行检测,结果表明用经混酸修饰后的样品制作出的传感器对SF6放电分解组分表现出较好的吸附性。此外,研究了温度对传感器吸附性能的影响,结果表明,温度在85℃时传感器表现出最强的吸附性。     

Electrochemical NOx sensors based on stabilized zirconia: comparison of sensing performances of mixed-potential-type and impedancemetric NOx sensors

A tubular sensor was fabricated by using yttira stabilized zirconia (YSZ) and ZnCr₂O₄ sensing-electrode (SE) aiming for detection of NOx at high temperature. The sensing characteristics of this YSZ-based sensor were evaluated at 700^∘C by means of potentiometric (mixed-potential) and impedancemetric methods with the variation of thickness of SE. A correlation between the thickness and the sensing performances was obtained for both types of NOx sensors. The mixed-potential-type sensor using ZnCr₂O₄-SE exhibited high NOx sensitivity when the SE thickness was small (4 μm). On the other hand, the impedancemetric sensor, employing the same oxide-SE, provided almost equal sensitivity to NO and NO₂ when the SE thickness was large (39 μm). In this case, the total concentration of NOx can be measured. The comparison of sensing mechanisms for the both sensors was briefly discussed.     

Measurement of tongue–artificial nipple contact pressure during infant sucking

To clarify the motor function of the infant tongue during sucking, we developed an artificial nipple that contained multiple small built‐in force sensors integrated with a PC‐based system which is capable of measuring tongue–artificial nipple contact pressures in real time. The force sensor is a cantilever structure with a small, thin stainless steel beam where an all‐purpose foil strain gauge is attached to the surface of the beam. An artificial nipple made of an elastomer containing these sensors is connected through an amplifier and an A/D converter to a PC via a USB port. Using this system, measurements were taken in three infants whose oral feeding was well established and in one infant of low birth weight. The results from each force sensor showed a pressure waveform of a nearly simple harmonic motion that indicated a peristalsis‐like movement of the tongue; the sucking frequency was found to be about two times per second. In addition, in the low‐birth‐weight infant, the pressure changed as the infant grew. © 2012 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

EPS用立式扭矩传感器的电磁分析

扭矩传感器是汽车电动助力转向系统（EPS）中的核心部件,根据电磁感应原理设计了一种新型立体磁电式扭矩传感器,首先介绍了传感器的圆柱式结构及工作原理,然后采用Ansoft Maxwell对传感器的电磁感应系统进行建模,通过静态分析,得到在使用电流为100 mA时系统磁场分布状态及静态输出电压,并利用瞬态模块模拟传感器工作过程,得到其动态输出信号为幅值随系统相对位置做呈正弦变化的高频感生电压,最后根据输出信号的特点设计了相应加法检波处理的原理电路。     

Experience with use of feedback in FES systems

Summary form only given. Technology for functional electrical simulation (FES) to restore movement in paralyzed limbs is discussed. In FES systems for restoration of standing and locomotion, the following sensory information is of interest: ground reaction forces and their spatial and temporal distribution, angular position and velocities, and relative position of the body or body parts towards the direction of the gravity vector. Three types of sensors that have been tested in FES system are described. These sensors are artificial, nonimplantable sensors; artificial, implantable sensors; and natural sensors