数字多用表100VDC点的校准

一、概述 1.测量依据JJG315-1983《直流数字电压表》检定规程和JJF1059-1999《测量不确定度评定与表示》。2.测量标准多功能校准仪,最大允许误差为±（0.0005Vs＋1mV）。3.环境条件温度：（20±2）℃,相对湿度：〈85%。4.测量对象分辨力为0.1V的数字多用表。     

数字多用表交流电压测量结果的不确定度评定

根据JJG34-1999《交流数字式电压表检定规程》,对数字多用表交流电压示值误差测量结果的不确定度进行了评定。     

直流电压校准能力测量审核结果分析

本文结合实际工作情况,依据JJG 315-1983《直流数字电压表》检定规程和JJF 1059.1-2012测量不确定度评定与表示,对多功能标准源直流电压校准能力测量审核进行了介绍,并对测量审核结果进行了误差评定分析,确保了实验室认可项目的准确、有效。     

JJF1587-2016使用中的建议

现行实施的JJF1587-2016《数字多用表校准规范》,合并了JJG315-1983《直流数字电压表检定规程》、JJG598-1989《直流数字电流表(试行)检定规程》、JJG724-1991《直流数字式欧姆表检定规程》,重新编写了数字多用表的直流电压、直流电流和直流电阻测量功能的校准内容,增加了数字多用表的交流电压...     

6(1/2)位数字多用表直流电压测量结果不确定度评定

在对6(1/2)位数字多用表直流电压进行测量时,不同电压值对应的测量不确定度不尽相同。本文以直流电压10V量程10V点为例进行测量结果不确定度的评定与分析。一、概述依据JJG315-1983《直流数字电压表试行》检定规程三、7.1,采用直流标准电压发生器法,校准数字多用表直流电压示值误差。选取FLUKE5720A作为高精度     

直流电子负载测量不确定度的评定

一、前言1.校准依据JJF（电子）30101-2007《直流电子负载》校准规范;JJG315-1983《直流数字电压表试行》检定规程;JJG598-1989《直流数字电流表（试行）》检定规程。2.环境条件环境条件：（23±5）℃;相对湿度：40%～75%。3.测量标准（见表1）4.被校准对象     

巧用Excel绘制直流电压参数的CMC

<正>一、不确定度评定本文依据JJG315-1983《直流数字电压表试行检定规程》中7.1的测量方法,对直流数字多用表的直流电压进行不确定度评定。选择FLUKE公司的多功能标准源5720A作为标准器,被检选用Agilent公司的六位半数字多用表34401A。5720A直流电压参数技术指标如表1所示。%由5720A的技术指标可以看出,在每段量程内的不确定度都随着被测量值的变化而变化。CMC的表示方法用被测量值或参数的函数表示最为合适。     

数字繁用表的选择与使用

文章根据《直流数字电压表检定规程 JJG315-83》、《直流数字式欧姆表检定规程 JJG724-91》、《直流数字电流表检定规程 JJG598-89》的要求,结合本人在实际工作中遇到的具体问题,论述了数字繁用表选择的主要因素、选择原则及使用中应注意事项。     

参考数字多用表直流电压的测量及不确定度评定

按照直流数字电压表检定规程中给出的标准传递法,对数字电压表进行测量,并根据不确定度评定方法,对直流电压的测量结果进行了不确定度评定.     

直流电桥电阻箱计量标准装置的建立

本文根据JJG166-93直流电阻器检定规程和JJG125-86直流电桥检定规程,建立了直流电桥电阻箱检定标准装置,根据不确定度评定方法,对此计量标准的测量结果进行了不确定度评定并进行了验证,同时测量了此计量标准的重复性和稳定性。     

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)。