中国参加温度关键比对结果分析

本文介绍了国际计量委员会(CIPM)组织国际关键比对的背景和已经开展的温度比对项目。对中国计量科学研究院参加的温度比对项目进行了系统介绍和结果分析。     

电子天平比对结果的分析与研究

根据浙江省质量技术监督局的安排,指定台州市计量技术研究院作为本次比对主导实验室,负责实施省内法定计量检定机构和社会第三方计量校准机构的计量比对工作。文章介绍了比对的技术方案、比对结果,指出电子天平校准工作中的不足,分析原因并提出建议和改进措施,有助于提高电子天平项目的检定校准技术能力,确保计量标准量值准确可靠。     

纳米尺度线宽的测量与Nano1国际关键比对

现代集成电路制造业、数据存储工业和微机电系统等行业的不断发展,对纳米尺度线宽的测量提出了越来越高的要求.目前的一些测量方法分别存在各自的缺点与不足,在缺少更高准确度计量标准的情况下,往往采用比对的方法使计量结果趋于一致.国际计量局在1998年把纳米尺度线宽计量确定为纳米尺度基本特征国际关键比对项目之一.文章对它的主要研究内容以及进展情况作了介绍.     

纳米尺度线宽的测量与Nanol国际关键比对

现代集成电路制造业、数据存储工业和微机电系统等行业的不断发展，对纳米尺度线宽的测量提出了越来越高的要求。目前的一些测量方法分别存在各自的缺点与不足，在缺少更高准确度计量标准的情况下，往往采用比对的方法使计量结果趋于一致。国际计量局在1998年把纳米尺度线宽计量确定为纳米尺度基本特征国际关键比对项目之一。文章对它的主要研究内容以及进展情况作了介绍。     

地方动态

正北京区县实验室开展计量比对活动为提高基层法定计量检定机构能力,近日,北京市西城区、丰台区、昌平区、顺义区计量检测所开展了绝缘电阻表、金属线纹尺、游标卡尺、交流指针电压表等4个项目的计量比对活动。此次计量比对活动不仅按照法定计量检定机构的管理要求,有效评价了相关检测项目的检定工作质量,还搭建了一个     

开展量值比对活动可以促进法定计量技术机构的发展

2004年以来，笔者曾代表本机构分别参加了江苏省计量科学研究院、无锡市计量科学研究所为主导实验室开展的煤气表、电能表和出租汽车计价器等项目的比对活动。在参与比对中，笔者深切体会到比对活动有利于计量技术机构的发展。     

“低温辐射计标准和国际比对方法的研究”通过验收

近日，国家质检总局在中国计量科学研究院主持召开了科技部科技基础性工作专项项目“低温辐射计标准和国际比对方法的研究”课题鉴定会。     

光度计响应度国际比对方法和结果

介绍光度与辐射度咨询委员会（ＣＣＰＲ）国际比对项目－光度计响应度的比对方案和在中国计量科学研究院（ＮＩＭ）的复现方法，并对国际比对做了简要分析。     

国际计量比对数据库投入使用

由ＮＩＳＴ开发 ,并经国际计量局认可的国际计量比对数据库已在Ｉｎｔｅｒｎｅｔ网络上投入使用。１９９９年１０月由３８个国家签署了“相互承认国家计量标准”的协议 ,从而建立了上述国家计量科研机构间进行关键项目比对的正式系统。根据国际计量局的报告 ,已经和正在进行的循环比对项目约１３０种。计量专家组将评定收入数据库的比对结果的可靠性。该数据库还将扩展到其它国家。国际计量比对数据库投入使用     

西北区域气象计量检定实验室比对项目通过专家评审

经过半年多的紧张工作,＂西北区域气象计量检定实验室比对＂项目日前顺利完成并通过专家评审。专家组对该项目工作和技术报告给予了充分肯定,认为该项目按实施方案的要求,在我国气象行业首次开展了区域计量检定实验室比对工作,完成了所有比对内容,比对方法科学、流程合理,结果良好。     

Estimation of Parameters of Universal Distribution of Moments of Failure of Products

A method is proposed for estimating the parameters of a mixture of exponential and Weibull distributions for which the accuracy of preliminary estimates obtained by graphical analysis is refined in accordance with the criterion of maximum likelihood. The efficiency of the proposed method is supported by the results of statistical modeling.     

Evaluation of optical properties of highly scattering media by moments of distributions of times of flight of photons

A novel method for the determination of the optical properties of tissue from time-domain measurements is presented. The data analysis is based on the evaluation of the first moment and the second centralized moment, i.e., the mean time of flight and the variance of the measured distribution of times of flight (DTOF) of photons injected by short (picosecond) laser pulses. Analytical expressions are derived for calculation of absorption and of reduced scattering coefficients from these moments by application of diffusion theory for infinite and semi-infinite homogeneous media. The proposed method was tested on experimental data obtained with phantoms, and results for absorption and reduced scattering coefficients obtained by the proposed method are compared with those obtained by fitting of the same data with analytical solutions of the diffusion equation. Furthermore, the accuracy of the moment analysis was investigated for a range of integration limits of the DTOF. The moment analysis may serve as a comparatively fast method for evaluating optical properties with sufficient accuracy and can be used, e.g., for on-line monitoring of optical properties of biological tissue.     

Analysis of the rate of propagation of the wave of change of boiling modes

An approximate analytical expression is derived for the velocity of the front of the wave of change of boiling modes on a rod and on a plate. The impact of the Thomson effect and of the heater orientation in the gravity field is included. Adequate agreement is demonstrated between the derived relations and experimental data.     

Estimation of potentialities of methods of summation of direct measurement errors

Conventional methods for summation of direct measurement errors are considered. Conditions under which these methods provide consistent results are stated. It is proposed to utilize for characteristic of the total error, its interval estimator or the half-sum of the value obtained by adding up its arithmetic and geometric random errors.Translated from Izmeritel'naya Tekhnika, No. 4, pp. 10–12, April, 1995.     

空压机轴承箱蜗壳温度探头油封改造

由于空压机进气侧轴承箱蜗壳温度探头密封效果不好,使空压机及其后续管道受到油污染。后将温度探头的O形圈密封改为骨架油封,杜绝了轴承箱漏油问题。文章简介空压机的结构和技术参数,详细介绍了骨架油封的制作和优点。     

Characteristics of mechanical properties of materials in studies of conditions of attainment of marginal states

It is shown that conditions of attainment of marginal states in the material of structural components are formulated on the basis of analysis of force and deformation criteria of formation and development of destruction. The parameters of these criteria are data on types of structural materials, standard and special characteristics of their mechanical properties, structural forms of considered elements of the equipment, and their operating stress loading. In this case, the construction of a system of state equations for describing interrelation of current damage, external actions, and responses to them is based on the concept of calculating variations in properties of materials at all stages of the design life cycle.     

Determination of parameters of microstructural inhomogeneity of deformation of metals by the method of modeling

The article suggests a method of evaluating the microstructural inhomogeneity of deformation of metals by modeling. The method includes the measurement of deformations of metal according to meshes of a dividing grid with small base and the calculation of the distribution parameters of microdeformations in model representation. It is shown that the modeling method makes it possible objectively to evaluate the microinhomogeneity of deformation of metals independently of the chosen mesh size of the dividing grid. New structural characteristics are introduced: the base and wave of variation expressing the degree of crumbling or amalgamation of metal grains by inhomogeneity of deformation.Translated from Problemy Prochnosti, No. 7, pp. 40–44, July, 1991.     

水三相点复现的不确定度评定

水三相点是开尔文热力学温度的唯一基准点，也是ITS-90国际温标重要的定义固定点。因此，水三相点不确定度分析对整个温标的建立、温度量值传递起着至关重要的作用。近3年来，中国计量科学研究院研制出一系列高质量的水三相点容器，加强了水三相点的研究，为不确定度的分析提供了更为可靠的实验依据。同时，不确定度的分析也是客观评价新研制容器性能的一个重要指标。因此，根据实验结果对新研制容器所复现的水三相点进行了不确定度评定。评定结果表明，其扩展不确定度为0．16mK(k=2．69，P=0．99)。