共查询到20条相似文献,搜索用时 31 毫秒
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OEM压阻芯片性能测试装置由2个平台构成,即硬件平台和软件平台,具有自动测试芯片性能和控制探针台功能.OEM压阻芯片性能测试可实现4寸(1寸=2.54 cm)芯片上近千个传感器图形的性能测试.每个图形测试项目包括桥路电阻、失调电压、漏流、击穿.对测试项目的合格判定标准实现了开放式管理,可根据不同类别的传感器芯片,设置不同的合格判定标准;在击穿电压测试项目中,对反向偏置电压设置实现了开放式管理,可根据不同的要求,设置不同的反向偏置电压,方便了应用. 相似文献
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针对当前对CO2焊机电源测试及其焊接过程分析的需要,开发出一套能自动测试弧焊电源性能的系统.通过对焊接过程中电弧电压、电源电流信号进行采集、处理,实现了对电焊机外特性的测试,同时可对焊接工艺性能做出实时评价.该系统具有智能化程度较高、人机界面友好、测试及数据处理功能齐全等特点,为以后焊机工艺技术的提高带来一定的推动作用. 相似文献
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本文介绍了热式质量流量计的测量原理及恒流式、恒温差式两种测量方法。根据热式流量计的测试原理。提出了用于小流量测量的恒电压式热式质量流量计的设计方案并进行了实验验证。实验表明在严格控制电压的条件下,流量计具有良好的性能。 相似文献
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针对电机铁芯磁性能测试中保持磁场强度H的波形为正弦形的问题,设计了一种基于数字信号处理器(DSP)全数字实时控制的逆变恒流源。分析了正弦波逆变电源斩波和逆变控制的一般方法和特点,控制系统前级采用同步Buck电路对母线电压斩波,斩波输出电压经过PI闭环控制实现了其在突加、突减负载时的稳定性。控制系统后级通过对电感电流的PID闭环控制和单极性正弦脉宽调制(SPWM)方式,实现瞬时跟踪给定的交流恒流源控制。实验结果表明逆变恒流源具有很好的静、动态性能和稳定性,输出信号谐波含量少,负载适应能力强,很好地实现了系统设计的要求。 相似文献
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Cizmar P Vladár AE Ming B Postek MT;National Institute of Standards Technology 《Scanning》2008,30(5):381-391
Resolution is a key performance metric, which often defines the quality of a scanning electron microscope (SEM). Traditionally, there is the subjective measurement of the distance between two points on special "resolution" samples and there are several computer-based resolution-calculation methods. These computer-based resolution-calculation methods are much more precise than direct measurement, but none of them can currently be considered an objective way of measuring the resolution. The methods are still under development; therefore, objective testing is necessary. One approach to algorithm testing is to use simulated images. Simulated images are very useful for this purpose because they can be well-defined in all parameters unlike the real SEM images. Simulated images can be generated that closely mimic the gold-on-carbon SEM test sample images that usually consist of bright grains on a dark background. Simulation can account for edge effect, roughness of the substrate, different focusing, drift and vibration, and noise. Shapes, positions, and sizes of the grain structures are random. The simulated images can be then used for testing the resolution-calculation methods, especially for finding how the particular properties of SEM images affect the resultant instrument performance and image resolution. To support this testing, NIST has developed and made available a reference set of simulated SEM images generated using the methods described in this article. 相似文献
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A. Noorul Haq T. Tamizharasan 《The International Journal of Advanced Manufacturing Technology》2007,31(11-12):1148-1155
Monitoring the condition of the engine compression ring in an engine operation is very important since it affects the engine performance. One of the most promising ring wear monitoring methods is based on the analysis of acoustic emission (AE) signals, which is an extremely powerful technique that can be deployed in a wide range of applications of non-destructive testing [Vallen Systeme (2000)]. This technique is already used for monitoring tool wear almost in all machining operations, but in this study, the AE signals were applied for monitoring ring wear in internal combustion (IC) engines. The AE signals generated in the ring sliding zone are very sensitive for correlation with ring wear, which in turn affects ring performance. This study was carried out with a single compression ring mounted on the piston. The AE signals were analyzed by considering signal parameters such as ring down count and RMS voltage [Krzysztof Jemielniak (2000) J Mater Process Technol 4752:1–6]. Analysis showed that the AE signal technique is applicable for ring wear monitoring in IC engines. 相似文献
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为了能获取真正的开路电压与短路电流,自动适应多种规格的太阳电池片的参数要求,对太阳电池的测试的电子模型与自适应多测试系统进行研究。首先在分析原有太阳电池测试系统的基础上,进行改进,使得跟随电压真正跟随到OV;然后采用多路电子开关等手段,使得测试线路实现了自适应多量程的测试。试验结果表明,系统能真正获取开路电压与短路电流,并且,能实现电压在0~50V,电流在0.7~5.6A之间的自适应测量,开路电压不一致性〈2.2%,短路电流不一致性〈3.2%,满足了单体太阳电池与小组件太阳电池的测量。 相似文献
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Increasing performance of vacuum insulator barriers is a common goal in pulsed power. Insulating performance is continually being improved while new methods are developed. Triple point shielding techniques have been shown to increase flashover voltage, but the role of cathode versus anode shielding is still not fully understood. Open circuit flashover characteristics were obtained for a coaxial geometry to view the effects of triple point shielding for this geometry. The tests included applying various combinations of triple point shields on zero and +45 degrees insulators. Shielding was tested at the cathode triple point outside of the dielectric and at the anode triple point inside the dielectric. The role of anode versus cathode triple point shielding was examined. Flashover voltage was observed to increase when either a cathode or anode triple point shield was applied; however, adding a shield to both regions lowered the flashover threshold. Both triple point regions were found to be important and dependent on each other for some coaxial geometries. 相似文献
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In this paper, an improved finite-control-set model predictive control method is proposed for active front-end rectifiers where the computational effort and parameter mismatch problems are taken into account simultaneously. Specifically, a desired voltage vector which only requires one exploration is directly selected by using a single cost function, and the process of selection of the desired voltage vector is optimized by using a sector distribution method. Meanwhile, a model reference adaptive system-based online parameter identification approach is presented to alleviate the parameter mismatch problem. The advantages of the proposed method summarized as follows: First, the proposed algorithm reduces the eight possible voltage vectors to one. The exhaustive exploration can be avoided while the control performance is not deteriorated. Second, the proposed controller can mitigate performance degradation caused by the model parameter mismatch. Simulation results under various parameters operating conditions are presented to demonstrate the efficacy of the proposed method. 相似文献
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研究了挟沙水流对混凝土的冲磨破坏机理及主要影响因素,分析了常用的混凝土冲磨试验方法,提出了旋转喷射式冲磨试验原理,并根据此原理研制了旋转喷射式混凝土抗冲耐磨试验机。与现有冲磨机相比较,该试验机的模拟冲刷过程更接近混凝土真实工况,并且可以实现不同冲刷条件下一定冲刷速度范围内的任意速度调节,冲刷速度高,冲磨效果好,能够有效地对不同配合比混凝土的抗冲磨性能作出比较。 相似文献
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为研究介电型EAP摆动驱动器的性能,设计制作了柔杆式介电型EAP摆动驱动器。对驱动器的摆动性能进行了测试,获得了不同施加电压下驱动器的摆动角度与阻转力。结果表明,随着施加电压的增加,驱动器的摆动角度、阻转力也在增加,且在电压较大时增加更快。此外,EAP的拉伸率对驱动器性能也有一定的影响,并指出了该驱动器在结构与性能优化的基础上,可潜在用于仿生机器人的摆动驱动。 相似文献
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This paper describes the measurement and test results on oil film thickness conducted with a self-contained gear testing machine, with pandimensional power flow, using an improved method of discharge voltage measurement. A series of experiments were conducted in an attempt to measure and analyse the lubrication regimes of involute and double circular arc gear with different lubricants under various working conditions. A formula is provided for calculating oil film discharge voltage following the recorded output of a level recorder. Experimental results show that such an improved method for discharge voltage is suitable for measurement of film thickness, and that the results are in keeping with the minimum film thickness formula for a double circular arc gear deduced by the authors. The relations between film voltage and the gear parameters of load, rotation speed, lubricant and oil temperature, are also discussed. It is asserted that such a test system has more reliable performance and is more suitable for measuring and analysing the lubrication regimes of gear transmissions than are ordinary experimental systems. 相似文献
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为了满足电容充电式无触点(CDI)磁电机定子出厂性能检测的需求,提高检测精度、效率以及自动化水平,研究开发了一种磁电机定子自动检测系统。基于LabVIEW测控平台,设计并开发了检测台人机界面,实现了手动和自动控制两种模式的转换运行;对磁电机电压信号进行了采集、滤波、时频和峰值处理,同步测试出了开路峰值电压和点火提前角等指标;采用三针放电模拟火花塞点火,通过对火花电压和电流同步积分运算得出了点火能量值。该系统通过实际检测台的开发验证,能够自动同时测试出两个定子的各项性能指标,效率提高80%,测试误差不超过1%。研究结果表明,该系统具有较高的测量精度和柔性,能显著降低测试成本和工人劳动强度。 相似文献
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Pejović MM Denić DB Pejović MM Nešić NT Vasović N 《The Review of scientific instruments》2010,81(10):105104
This paper presents realization of a digital embedded system for measuring electrical breakdown time delay. The proposed system consists of three major parts: dc voltage supply, analog subsystem, and a digital subsystem. Any dc power source with the range from 100 to 1000 V can be used in this application. The analog subsystem should provide fast and accurate voltage switching on the testing device as well as transform the signals that represent the voltage pulse on the device and the device breakdown into the form suitable for detection by a digital subsystem. The insulated gate bipolar transistor IRG4PH40KD driven by TC429 MOSFET driver is used for high voltage switching on the device. The aim of a digital subsystem is to detect the signals from the analog subsystem and to measure the elapsed time between their occurrences. Moreover, the digital subsystem controls various parameters that influence time delay and provides fast data storage for a large number of measured data. For this propose, we used the PIC18F4550 microcontroller with a full-speed compatible universal serial bus (USB) engine. Operation of this system is verified on different commercial and custom made gas devices with different structure and breakdown mechanisms. The electrical breakdown time delay measurements have been carried out as a function of several parameters, which dominantly influence electrical breakdown time delay. The obtained results have been verified using statistical methods, and they show good agreement with the theory. The proposed system shows good repeatability, sensitivity, and stability for measuring the electrical breakdown time delay. 相似文献