System identification of tendon reflex dynamics.

Patellar tendon reflexes were evaluated in 12 healthy adult subjects using several measures of the reflex responses and of the system input-output relationship. A hand-held instrumented hammer was used to tap the patellar tendon and to elicit the reflex response. Tendon reflex dynamics were estimated using the recorded tapping force (as input) and the quadriceps muscle electromyogram and knee joint extension torque signals (as output). A dome-shaped rubber pad was mounted onto the most sensitive spot on the patellar tendon, where it served as a tapping target, and helped to reduce the reflex variability significantly (p < 0.01). The input-output properties of the system relating the reflex torque to the tapping force were characterized using several measures: the tendon reflex gain (Gtr), contraction rate (Rc), and half-relaxation rate (Rhr). Reflex loop delay (t(d)) was estimated using the delay from the onset of tapping force to the onset of reflex torque. We determined that these system parameters provided significantly more repeatable and consistent characterization of tendon reflexes than did reflexive torque or EMG signals alone (p < 0.025). The input-output relationship relating the EMG signals of the stretched muscle to the tapping force was also identified to help characterize neuromuscular dynamics of tendon reflexes. The observed sensitivity and consistency of the reflex system measures suggest that with appropriate simplification of the instrumentation, these methods may prove useful in routine clinical practice, and may allow more precise quantification of the tendon jerk than is currently feasible with standard clinical tests.     

Development of a computed tomography algorithm for ion temperature measurement

A new algorithm for 2D ion temperature measurement was developed by including Gaussian fitting of Doppler broadened spectral lines in tomography reconstruction. A modified Bessel function model and squared cosine function model were used to satisfy both the annular boundary conditions in space and the Gaussian profile of spectral lines in wavelength. This method was found much more robust against projection signal errors than the conventional Gaussian‐fitting method at each wavelength. © 2003 Wiley Periodicals, Inc. Electr Eng Jpn, 142(4): 1–8, 2003; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.10114     

Development of a laser wavefront sensor for measurement of discharges in air

A laser wavefront sensor of the Shack‐Hartmann type capable of simultaneous measurement at two wavelengths was constructed. The sensor uses a single optical path, and is suited for applications such as high‐voltage discharges in air, in which large insulation distances are necessary. The sensor was used to detect optical path differences due to an impulse discharge in air across a needle–plane electrode gap of gap length 17 mm. Optical path differences were measured at laser wavelengths of 532 and 1064 nm at 1.6 µs after insulation breakdown across the gap. From the difference in optical path differences at the two wavelengths, a line‐integrated electron density distribution in the direction perpendicular to the gap was obtained near the high‐voltage electrode. The distribution had a peak value of 1.4 × 10²⁰m^?2 and a full width at half maximum of 4.4 mm. Because of the coverage of a large observation area including the entire gap, the spatial resolution was 1.4 mm, which was inadequate to obtain the precise form of the electron density distribution. However, the results show the possibility of applying laser wavefront sensing to electron density measurement. © 2004 Wiley Periodicals, Inc. Electr Eng Jpn, 146(4): 10–17, 2004; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.10247     

Development of a contactless measurement method for transmission line surge voltage waveform

This paper proposes a contactless method to measure a surge voltage waveform on an overhead transmission line and on a cable sheath enclosed in a corrosion‐proof layer. To measure surge voltage and current waveforms on the overhead line, the method is based on electromagnetic coupling between the overhead line and a surge sensor, composed of a closed loop which is a distributed parameter line. The surge waveform is estimated from the induced voltage to the closed loop and from a Z‐parameter theory. To measure the cable sheath voltage waveform, the method is based on electrostatic coupling between the sheath and a detecting electrode, which is portable and detachable, and is composed of quite simple components, and its potential dividing ratio is adjustable using a lumped capacitor. The proposed method is inexpensive, is easy to measure surge waveforms with reasonable accuracy, and also is applicable to surge measurement on a live line because of its contactless nature. © 2001 Scripta Technica, Electr Eng Jpn, 136(1): 9–15, 2001     

新型电缆导体直流电阻测量仪的研制

采用小电流电压比率法测量原理 ,研制了一种智能型的电缆导体直流电阻测量仪。它能够快速精密地测量导体的直流电阻 ,并能自动转换显示其 2 0°C、单位长度 (1km)的电阻和 2 0°C时的电阻率。该仪器还具有液晶汉字化显示、蓄电池供电和便于现场使用等特点。     

蓄电池析气测量仪的研制

介绍了析气测量仪的设计方案、结构、原理和使用,测量时将蓄电池析出的气体通过导气管流入特制的量筒中,气体体积在100mL以内,储存在量筒中并可直接读出气体体积,每到100mL,通过位置传感器控制放空量筒内的气体,并由计数器记录放空次数。该仪器解决了将蓄电池放在水中两个电极电解水产生气体,来测量蓄电池析出气体体积的不准确和麻烦的问题,并能观察析出气体的快慢。     

磁性薄膜噪声测量系统研制

利用惠斯通电桥和两极放大电路在磁屏蔽腔中设计开发了磁性薄膜低频噪声测量系统.通过内推法和外比法测试证明该系统测量精度高,稳定性好,能够完成加磁场环境下的低频噪声测量.利用此系统发现各向异性磁电阻元件在退火后1/f噪声明显降低.该装置对于磁性薄膜提供了一种非破坏的有效检测手段,同时也提供了检测磁性转变内在机制的一种有效途径.     

基于某型数据存储压力仪的图形用户界面开发

可重构数据存储压力仪是一种新型的爆炸冲击波超压测试仪器,为了提高该压力仪测试数据判读的速度和准确性,进一步对测试数据进行分析处理,本文通过对可重构数据存储压力仪数据存储格式的分析,应用MATLAB语言及其用户界面开发环境(GUIDE),对该压力仪自带的数据处理软件进行了二次开发,设计了界面友好、交互性强、数据处理功能强大的图形用户界面,在实地试验测试中,该软件实现了对所采集数据的快速精确的读取和分析,有较强的实际应用价值.     

电动大巴双向电能计量装置的设计与实现

介绍了一种基于微处理器和专用电能计量芯片的直流双向电能计量装置,实现对电动大巴能耗的全数字化计量,详细分析了系统的硬件电路结构和主要软件设计,并提出多项抗干扰措施提高计量的电磁兼容性能。实验结果表明,该装置测量直流电能的精度为可以达到百分之一,实际装车运行稳定可靠。     

新型矫顽力精密测量仪的研制

介绍了一种新研制的矫顽力测试仪,该装置基于PC机丰富的软件资源和强大的数据处理能力,实现矫顽力的自动精确测量,测量方法上,通过气源驱动将直流剩磁转换为交流电信号以克服零漂,运用带通滤波和相关分析抑制干涉;通过线性回归分析寻找准确的过零点,应用优化算法提高测量速度。与现有同类产品相比,测量重复性和准确性有了较大的提高。     

防振锤功率特性两种测试方法的比较

测量防振锤的功率特性按其控制条件不同分为定振幅法和定振速法 ,从理论和实验两方面论证了定振速法比定振幅法更接近防振锤在实际线路中的运行情况 ,其结果也更能反映防振锤的实际功率特性     

测量航空发动机转速的便携式系统的开发

本文详细介绍了一种测量航空发动机转速的以FPGA(XC2S100E 6PQ208C)为测量转速核心处理芯片,嵌入式单片机(S3C2410)为数据处理器的便携式系统的设计方法.详细介绍了系统的硬件组成和软件设计,并利用ISE6.2的集成开发环境编写了测量转速的软件程序,给出了系统测量的仿真波形.仿真结果表明,该设计方案符合设计要求.     

一种角位移测量仪的研制

介绍一种用于光学测量投影仪的角位移测量仪。它通过硬件电路对一个旋转编码器输出的角位移信号进行辨向和计数,再使用一个微处理器对辨向信号和计数信号进行处理,得到被测工件在Z旋转方向的位移值,最后对位移测量值进行误差修正,得到该仪器的测量分辨率为1’且测量精度为±3．9’。实验表明：所研制的角位移测量仪具有准确、可靠的特点。     

Development of a laser radar using LDS dye and sum frequency generation for NO2 measurement

A laser radar for measuring vertical concentration profiles of atmospheric NO₂ was developed. The laser transmitter uses an LDS765 dye laser pumped by a Nd:YAG laser. The dye laser output is converted to wavelengths 446.8 and 448.1 nm, which are used for NO₂ measurement, by sum frequency generation (SFG) using a pair of KD^*P crystals. The dependence of the LDS765 dye laser output on wavelength and dye concentration was investigated, and the performance of the laser transmitter was evaluated. Compared to the Coumarin 445 dye laser conventionally used for NO₂ measurement, this laser transmitter represents a significant improvement in output stability, as well as in maximum output energy and overall conversion efficiency. Using the newly developed laser radar, NO₂ concentrations of 20 to 40 ppb were measured for vertical range 500 to 1000 m, which were in rough agreement with values monitored on the ground. © 2003 Wiley Periodicals, Inc. Electr Eng Jpn, 144(2): 26–33, 2003; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.10231     

多通道精密时间间隔测量系统的研制

为了更方便地在科学研究和工程实践中对多个物理事件之间的时间间隔进行测量,扩大测量量程,提出了一种多通道、大量程的精密时间间隔测量系统的研制方法。系统的设计采用集成的数字时间转换芯片TDC-GPX,运用管道式预处理和逻辑门延迟线方法,能实现8个通道的同时测量,测量精度可达50 ps,测量范围为5.5 ns~4 294 s,在TDC-GPX芯片的内部再触发模式下,通过编程进一步扩展还可以实现无限制测量量程的测量。     

水电站压力管道系统较大比尺水击模型试验设计方法

理论上讲 ,按重力相似准则设计模型 ,并保证模型材料与原型材料的弹性相似 ,即能在模型上模拟原型的水击现象。但对于较大模型比尺 ,很难找到理想的模型材料。为此 ,本文提出了模拟水击的时间变态模型设计方法 ,通过图解法验证了其比尺关系。最后 ,结合糯扎渡水电站引水系统进行了模型设计和试验研究     

适用于工业企业变电站的保护测控一体化装置开发

大型工业企业变电站对自动化产品的需求与日俱增,但与电力系统主电网中的变电站相比有其特殊性,借鉴成熟的电力系统变电站综合自动化技术和以太网通信技术,基于新型的MCU硬件平台和VxWorks嵌入式操作系统,开发了一套系列化的保护测控一体化装置,为实现企业变电站的自动化提供了先进的解决方案.针对目前企业变电站中应用的保护测控装置普遍存在的问题,提出了相应的解决方法,实践证明该装置能很好地适应工业企业变电站的特殊运行要求.     

测量高压差分探头1 MHz共模抑制比窄带放大器的研制

为了完整测量高压差分探头共模抑制比性能,需测量其50Hz~1MHz频率处的共模抑制比值。由于标准信号源的输出电平能力随着输出频率的升高而不断减小,1MHz时仅为20V左右,经过差分探头的衰减及共模抑制作用,使差分探头1MHz时共模输出信号电平极小,无法利用示波器进行测量。故研制了一台中心频率为1MHz的窄带放大器,该窄带放大器由低噪声高带宽放大单元和谐振选频单元组成,试验结果表明了其在输入电平50μV~1mV范围内的增益线性度优于±0.5dB,适用于差分探头1MHz频率处共模抑制比的测量。     

一种实用的功率测量方法的设计

本文介绍一种实用的时分割乘法器的原理.由实测知具有准确度高、稳定性好等特点.此电路结构简单,对元器件要求不苛刻.该电路已在电力监控系统中得到了实际应用.