A Noninvasive, on Wafer Method to Determine the Intrinsic Stress of a Polymer Layer

The method described in this paper allows an investigator to determine the intrinsic stress of a polymer layer in a way that does not result in damage to devices or test structures. The method requires that a small area of the polymer be released from the substrate to form a diaphragm. The diaphragm is stimulated with acoustic white noise and the diaphragm movement is monitored with a laser vibrometer. The first few resonance frequencies of the diaphragm are obtained using a laser vibrometer and then those frequencies are used to calculate the membrane intrinsic bi-axial tension.     

NATA: 50 years experience with accreditation

 Laboratory accreditation is becoming increasingly accepted around the world as a means of identifying technically competent laboratories. It is also being used as a mechanism for the acceptance of test data both nationally and internationally. The concept and mechanisms of accreditation have been developed over the past 50 years. The first national laboratory accreditation system appeared in Australia in 1947. This organisation, known as the National Association of Testing Authorities (NATA), has since taken a leading role in developing accreditation practices that are now used world-wide in evaluating testing, measurement and calibration laboratories. This paper examines the development of the world's first and largest laboratory accreditation system, and looks at the difficulties and triumphs in gaining acceptance and recognition by government and industry of the benefits of laboratory accreditation. Received: 24 June 1996 Accepted: 25 June 1996     

Controlling the quality of testing

 This article mainly focuses on the testing of products, materials, etc., but the general principles are applicable in a broader perspective. Quality of testing should be judged based on fitness for purpose. This judgement includes both objective and subjective elements. The possibility to make decisions and other professional judgements based on test results alone is discussed and compared with the decisions and judgements being made through the certification and inspection process. Quality, including the uncertainty of the test results, depends on many factors, and in order to make necessary improvements in the testing procedures based on the customers' needs, the right issues should be addressed. The question arises as to whether, in laboratories' quality systems and in the accreditation and certification process, attention is really paid to those factors that are crucial to obtaining reliable results.     

Can the new ISO Guide 25/EN 45001 create better confidence in laboratory operations?

 Confidence in laboratory operations is discussed based on the ongoing revision of the ISO/IEC Guide 25. Confidence is a subjective attribute, which also depends on whose interest is considered. New and better-defined quality systems and technical elements will be included, and these are beneficial to the transparency of laboratory operations, as well as to the accreditation process. The ultimate aim is, of course, to satisfy customers. The testing laboratories' industrial customers are, however, generally unfamiliar with the ISO/IEC Guide 25 and accreditation. The main reason for improved confidence in testing and calibration laboratories is foreseen to come from closer interaction between laboratories and their customers.     

基于单神经元PID控制器的压电陶瓷控制方法

卫星地面综合测试是卫星研制过程中的重要环节,对系统功能验证及性能评估具有重要作用。传统的卫星地面综合测试系统存在研制周期长、投入较大、自动化流程不够完整、可重用性较差等不足。而北斗导航卫星地面综合测试系统采用分布式、高实时性、可配置、多主机的集成体系结构,是集计算机通讯、实时控制、实时数据处理、事后分析等功能于一体的测试系统,适用于从卫星总装集成到发射各个阶段的电气测试。通过卫星系统级的各项接口、功能、性能指标测试,表明该系统满足支持系统论证、状态确认、问题排查等测试需求,有力支撑了北斗导航卫星的成功发射和在轨运行。     

基于超声波和云测试的油井液面测试系统研究

针对目前油井液面深度测试系统测量范围小、误差大、稳定性低的缺点,提出了基于声波法测动液面原理,利用时间序列分析技术、新息自适应卡尔曼滤波技术来实时检测回波信号,进而实现对油井液面深度的高精度测量和噪声处理;选用FPGA和云测试技术成功实现了油井液面深度测量系统的远程化和网络化。基于云测试的油井液面远程监测系统目前已在油田生产现场通过测试,测试结果表明,系统稳定,算法实时、高效,动液面深度测量误差小,测量精度高,能满足实际工程应用。     

新型对开门高低温动态试验箱研制

介绍了新型对开门高低温动态试验箱的研制过程,包括系统热负荷计算、复叠制冷循环系统的热力计算等。并根据系统的热力计算,进行了冷凝器和蒸发器的结构设计以及主要部件压缩机和通风机的设计选型。     

指数分布场合下步进应力加速寿命试验的Bayes分析

当寿命分布为指数分布时，本文给出了步进应力加速寿命试验的一种新的Ｂａｙｅｓ估计，为计算上的方便，本文还给出一种近似方法，数值例子表明，此方法简便可行。     

The reproducible properties of correct forecasts

Each period, one outcome out of finitely many possibilities is observed. Each period, a forecaster announces some probability for the future outcomes based on the available data. An outsider wants to know if the forecaster has some knowledge of the data generating process. Let a test be an arbitrary function from sequences of forecasts and outcomes to {0,1}. When the test returns a 0 the test is said to reject the forecasts based on the outcome sequence. When the test resturns a 1 the test is said to not reject the forecasts based on the outcome sequence. Consider any test that does not reject the truth, i.e. it does not reject when the announced forecasts are the conditional probabilities of the data generating process. Based on Fans (1953) Minimax theorem, I show that it is possible to produce forecasts that will not be rejected on any sequence of outcomes. Journal of Economic Literature Classification Number:D83 LearningI thankfully acknowledge financial support from the National Science Foundation grant SES 0109650. I also thank a referee for useful comments. All errors are mine.     

光纤陀螺数字闭环控制系统模型实验研究

数字闭环光纤陀螺的动态性能受控制系统设计的影响.根据光纤陀螺数字闭环检测过程,建立了控制系统的数学模型.为在全频带内对模型进行验证,提出了基于Faraday效应的光纤陀螺频率响应测试方法,对该测试方法与角振动台测试方法的等效性进行了分析.设计了频率响应测试系统,测试范围大于50 kHz,波形失真小于0.1%.实测了采用一阶积分控制算法的数字闭环光纤陀螺频率响应.实验结果表明模型误差小于8%.