对JJG145-2007《摆锤式冲击试验机》检定规程中阿题的商榷

针对JJG145-2007<摆锤式冲击试验机>检定规程中相对偏差计算公式的问题进行讨论,并提出相应的改进建议.     

浅议数显卡尺之细分误差

本文针对计量检定规程JJG 30-2012《通用卡尺》中新增的检定项目“细分误差”进行分析解读，并对数显卡尺的常见故障提出解决方法。     

带表卡尺示值误差检定方法的探讨

通过对带表卡尺、游标卡尺和百分表结构及原理的比较,以及多年来在使用、检定与调修带表卡尺中遇到的问题,结合《通用卡尺》现行国家检定规程JJG 30-2012中,对带表卡尺示值误差检定点规定得太少,和检定点不均匀所产生的误差盲点进行了分析,并对规程提出建议.     

电子汽车衡检定中的误差控制

根据最新JJG 539-2016《数字指示秤检定规程》的要求结合实际检定工作的经验,笔者对电子汽车衡在检定中产生的误差进行了分析,提出了电子汽车衡检定中误差控制的几点建议。     

医用超声诊断仪的原理与检定技术

对医用超声诊断仪的成像原理、显示模式及影响分辨力的几个重要因素作了阐述 ,并对JJG63 9- 98检定规程提出了建议     

检定规程要正确理解

读了贵刊１９９８年第４期上刊登的《百分表检定之我见》（以下简称《百分表》）一文后,对于文中提出的部分观点,笔者提出自己的看法和薛祖均同志商榷。根据ＪＪＧ３４－９６指示表（百分表和千分表）检定规程（以下简称规程）规定,检定百分表的示值误差时,应“先将检定仪和百分表分别对好零位”。笔者认为《百分表》文中对该款的理解有些不妥,它没有把规程作为一个整体来考虑,只是片面的理解规程的某一部分,从而忽略了规程各条款之间的联系。根据规程第五条“指针与表盘的相互位置”的规定：“指示表的测杆处于自由状态时,调整表盘…     

对《JJG799—92三坐标测量机检定规程（试行）》几点建议

根据多年的实践经验以及参考一些国外标准，对现行的《三坐标测量机检定规程（试行）》中的一些问题作了讨论并提出修改建议，希望使现有的检定规程修改后更符合实际工作需要。     

带表卡尺示值检定点与误差盲点问题的探讨

针对带表卡尺最新国家检定规程中，对检定点规定的太少和检定点不均匀所产生的误差盲点进行了分析讨论，并介绍了解决方法和修改规程的建议。     

压力表示值检定中所遇问题的探讨

本文介绍了在压力表的示值误差检定工作中,相关规程的检定方法描述欠妥导致不能快速有效读取被检定压力表最大量程点的示值误差甚至损坏被检压力天的问题,并针对此问题提出了笔者的检定方法建议。     

于完善JJG 828-1993激光千分尺平行度检查仪检定规程的建议

针对JJG828-1993激光千分尺平行度检查仪检定规程示值误差项在要求和检定方法上存在的问题,从量值传递原则和示值检定段细分化两个方面提出几点建议.     

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)。