Removing divergence of JCGM documents from the GUM (1993) and repairing other defects

The mission of the Joint Committee for Guides in Metrology (JCGM) is to maintain and promote the use of the Guide to the Expression of Uncertainty in Measurement (GUM) and the International Vocabulary of Metrology (VIM, second edition). The JCGM has produced the third edition of the VIM (referred to as VIM3) and a number of documents; some of which are referred to as supplements to the GUM. We are concerned with the Supplement 1 (GUM-S1) and the document JCGM 104. The signal contribution of the GUM is its operational view of the uncertainty in measurement (as a parameter that characterizes the dispersion of the values that could be attributed to an unknown quantity). The operational view promulgated by the GUM had disconnected the uncertainty in measurement from the unknowable quantities true value and error. The GUM-S1 has diverged from the operational view of the uncertainty in measurement. Either the disparities should be removed or the GUM-S1 should not be referred to as a supplement to the GUM. Also, the GUM-S1 has misinterpreted the Bayesian concept of a statistical parameter and the VIM3 definitions of coverage interval and coverage probability are mathematically defective. We offer practical suggestions for revising the GUM-S1 and the VIM3 to remove their divergence from the GUM and to repair their defects.     

电磁机构三维动态特性测试及数据处理与分析

为寻求电器电磁机构动态过程的规律,提出一种单相机三维测试新方法,将单台高速摄像机和光学成像系统相结合,对电磁机构进行了三维动态特性测试,通过图像处理得到电磁机构三维动态特性曲线.对三维动态特性测试数据样本函数的最佳估计值和不确定度等重要特征量进行分析,研究了测试引起的不确定度与测试次数的关系,根据不确定度的变化趋势确定了样本容量.利用数理统计的方法对多组三维动态特性测试数据进行了处理,分析了电磁机构的三维动态特性.研究结果表明利用三维动态特性测试和数据处理方法,能够有效地分析电磁机构三维运动过程和机构运动分散性,为电器产品的优化设计和工艺改进提供依据.     

PLC在潜水泵电性能检测系统中应用

针对潜水泵电性能检测系统,介绍其整体的硬件结构、原理以及关键技术,阐述ＰＬＣ在该系统中的作用和ＰＬＣ的软件结构。     

自由曲面测量若干关键问题的研究

结合国内外研究现状 ,对自由曲面测量中曲面CAD模型已知时测点的自适应分布、测量路径优化、自由曲面形状误差评定和 CAD模型未知时的测量规划和测点数据处理等几个关键问题的实现方法进行了分析研究 ,并对测点的自适应分布做了仿真研究 ,证明了其有效性     

阀门流量流阻测试装置测量不确定度的研究

分析了影响阀门流量流阻测试装置测量不确定度的主要因素,以及流量系数与流阻系数测量不确定度的求解方法,并通过A类不确定度方法举例计算。     

近红外光谱分析技术在食品质量安全检测分析中的应用

本文简要介绍近红外光谱的发展历程、原理和应用特点,综述其在食品质量安全检测领域中开展掺伪使假、原产地鉴别、成分分析等方面的研究与应用情况,并对近红外光谱检测技术存在的问题以及今后的应用前景进行展望。     

Crack identification in a freely vibrating plate using Bayesian parameter estimation

In this paper a new approach is proposed for identifying the presence and location of a crack in a simply supported plate undergoing free vibration. Specifically, the approach uses a Markov-chain Monte-Carlo implementation of Bayes’ Rule to estimate the crack parameters (i.e., its location, orientation, and size) and their probability distributions. Special attention is paid to developing a fast and accurate forward model for the response of the cracked plate. To generate the required time series, a semi-analytical free response is calculated using an FEM based eigen-solution. To speed up the simulations, modified elements are used at the crack tips; this permits a more course mesh without sacrificing accuracy. The approach is demonstrated to be effective at identifying all of the crack parameters. Furthermore, a natural by-product of this method is that it also provides a confidence (credible) interval for each of these parameters. The results show the utility and accuracy of this method in identifying cracks of various sizes, orientations, and locations.     

步距规检测数控机床直线轴的技术研究

针对数控机床直线轴(以下简称直线轴)的几种检测方法,重点介绍了用双测头法(或多测头法)配合步距规,检测大于步距规尺寸的直线轴的方法.此方法极大地扩展了步距规的使用范围,是数控机床检测技术的一大创新,对机床检测机构、数控机床制造和使用单位均有很大的应用与参考价值.     

Bayesian networks: application in safety instrumentation and risk reduction

The Safety Integrity Level (SIL) of a Safety Instrumented Function (SIF) depends on failures of the various components involved in performing the function. These failures depend on various factors and can be random hardware failures and/or systematic failures. Failure of a SIF need not necessarily result in a hazardous event when there are other layers of protection. Hence the residual risk probability that is left out after various layers of protection is of interest and it should be tolerable. In order to find the residual risk due to a hazard we need to know the demand rate of the hazard, the failure rates of various layers of protection and the factors which influence these failures. So the failure rates are not static and are dynamic, as various factors come into play during the lifecycle of the protection devices involved. In this paper the author proposes Bayesian belief networks to build the scenario based hazard probability model and uses that in the post-design phase to track the residual risk probability. An example is used to illustrate the application.     

计量测试中计算机技术的应用

本文从仪器内置高性能PC机、虚拟仪器、计算机控制下的自动测试、证书与数据处理与计量网络化管理几个方面介绍了计算机技术在现代计量测试中的应用,说明了计算机技术在现代计量测试中的重要意义。     

基于法线方向的点包容检测

过待定点作一射线,此射线可能与多边形的某几条边有交点,从待定点向这条边的两端点作两个向量,求这两向量的法线方向,对法线方向进行计数。若法线方向为正向,将计数器加1;若法线方向为反向,将计数器减1。求待定点与每条相交边的两向量的法线方向并计数,当法线方向的正反次数相同时,待定点在多边形外,否则在多边形内。此算法避免了某些其他算法的错误,计算量很小,简单易行。通过编写程序计算验证表明,算法简单有效、稳定可靠,对简单多边形、自相交多边形及带孔多边形等多类情况同样适用。     

Spatial scanning for anomaly detection in acoustic emission testing of an aerospace structure

Acoustic emission (AE) monitoring of engineering structures potentially provides a convenient, cost-effective means of performing structural health monitoring. Networks of AE sensors can be easily and unobtrusively installed upon structures, giving the ability to detect and locate damage-related strain releases (‘events’) in the structure. Use of the technique is not widespread due to the lack of a simple and effective method for detecting abnormal activity levels: the sensitivity of AE sensor networks is such that events unrelated to damage are prevalent in most applications. In this publication, we propose to monitor AE activity in a structure using a spatial scanning statistic, developed and used effectively in the field of epidemiology. The technique is demonstrated on an aerospace structure - an Airbus A320 main landing gear fitting - undergoing fatigue loading, and the method is compared to existing techniques. Despite its simplicity, the scanning statistic proves to be an extremely effective tool in detecting the onset of damage in the structure: it requires little to no user intervention or expertise, is inexpensive to compute and has an easily interpretable output. Furthermore, the generic nature of the method allows the technique to be used in a variety of monitoring scenarios, to detect damage in a wide range of structures.     

MSA在压力试验机精度检测中的应用研究

将压力试验机精度检测纳入测量系统分析的范畴，综合应用测量系统分析和统计过程控制中已经取得的研究成果，对压力试验进行统计分析，从而掌握其统计规律，揭示其存在的可指出原因。给出了以加载速率作为重要研究对象的测量系统分析的实施方法。     

螺杆压缩机的使用维护问题浅析

根据阿特拉斯螺杆压缩机的工作原理、基本结构和特定的操作条件,分析了甲醇厂阿特拉斯空压机在运行中出现的问题,采取了相对的措施进行维护保养,保证了空压机的连续稳定运行。     

脉冲涡流无损检测技术综述

不同于传统的谐波激励的涡流检测方法,脉冲涡流检测采用方波或阶跃方式激励,其测量的是涡流在构件中的衰减。由傅里叶理论可知,脉冲涡流激励中包含多种频率成分,根据电磁场理论,低频电磁波有更深的穿透深度,因而也就可能检测出更深的缺陷。由于脉冲涡流检测时,激励已经停止,因而传统涡流阻抗分析方法已经不适用于脉冲涡流检测信号分析,需要寻找新的信号处理方法或数据解释方法;同时由于导磁材料与非导磁性材料特性不同,信号特性差异极大,上述问题不论从理论上还是从工程上对脉冲涡流检测技术都提出了极大的挑战。从检测理论模型、传感器、信号处理方法及工程应用等方面,对脉冲涡流检测技术作论述,指出该技术进一步发展需要研究的问题,更好地推动脉冲涡流检测技术的发展。     

A measurement and testing method for lubrication regimes in gear transmissions

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.     

测量系统分析(MSA)在齿轮生产过程中的应用

测量系统分析(MSA)的概述,对计量型数据进行五种分析,包括稳定性、偏移、线性、重复性与再现性;对计数型数据进行Kappa统计量的计算,从而判定在齿轮生产过程中的测量系统的状态、可接受程度与改进方向.     

断面流量测验方法对比研究

文章介绍了3种常见的断面流量测验方法及其工作原理,并对3种方法进行对比研究,综合分析了3种方法的适用范围、各自的优缺点,对断面流量测验方法的改进和研究具有一定的指导意义。     

Subpixel position measurement using 1D, 2D and 3D centroid algorithms with emphasis on applications in confocal microscopy

The accuracy with which centroid algorithms in 1D, 2D and 3D can estimate an object's position has been investigated. Three factors that can influence the method's accuracy have been investigated: systematic error of the algorithm, influence of photon noise and the influence of perturbations such as scanning nonlinearity. The variation of the accuracy with parameters that are relevant for confocal microscopy, such as object diameter and photon noise/pixel, has been considered. Theory and simulations presented show that the variation of the accuracy with respect to such parameters can differ drastically between the 1D, 2D and 3D cases. Experiments performed using microspheres show that the magnitudes of the three types of error can be approximately the same under normal operating conditions and that it is therefore necessary to take all three into account when assessing the total error.     

Application and evaluation of optical distance measurements in geometrical quality testing of microgears

Microgears are increasingly important in industry. Compared to normal gears, the quality assurance of microgears needs more accurately measured data and simple but feasible measurement methods because of their dimension particula