浅析天然气能量计量系统的检定现状

针对我国天然气流量计量向能量计量过渡的问题,介绍了国内外能量计量检定技术的现状,天然气能量计量的技术标准,能量计量系统组成、技术和计量要求,分析了能量计量的溯源性以及如何对能量计量系统进行计量控制.从完善天然气能量计量的标准体系、推行天然气能量计量试点、建立能量计量保证体系和溯源链等方面阐述了我国今后天然气能量计量的工作要点,以期促进我国天然气计量与国际接轨.     

对天然气发热量测定溯源体系的探讨

国际上天然气计量的方式主要有3种：体积计量、质量计量和能量计量,但在天然气贸易计量中以能量计量为目前国际通行的也是最公平的方法。随着人世和天然气市场竞争的加剧,天然气计量准确性和合理性倍受关注。目前,国家发改委对原油、成品油和天然气的计量方式都提出了与国际接轨的要求,大型贸易的天然气交接计量将采用能量计量方式。然而要推广实施天然气能量计量方式,迫切需要解决的问题是其相关技术的标准化问题。天然气由体积计量向能量计量转化,迫切需要有权威、准确的测量方法作为技术支持。     

上海燃气计量的现状和发展趋势

通过对上海燃气计量发展历史和现状的研究分析,指出上海目前已基本解决了城市人工煤气出厂计量和销售公司与用户之间的贸易计量,但在天然气计量领域仍存在不少问题,亟需建立一套高压天然气流量计量标准装置,以解决高压管道流量计的量值溯源,进一步提出了上海燃气计量发展方向和趋势.     

计算机智能计量系统在天然气计量方面的应用

随着改革开放的不断深入,天然气在我国国民生产中的地位越来越重要,实现自动计量、智能计量及数据远传计量已是天然气计量技术发展的必经之路。文章主要介绍了计算机智能计量系统在天然气计量方面的应用。     

天然气流量计量技术发展趋势

天然气流量计量是天然气生产、输送和销售的关键环节,本文分析了发展天然气计量技术的意义,结合我国天然气工业发展的需要对天然气计量技术的发展趋势进行了预测。     

天然气计量中存在的问题及对策

文章分析了天然气计量的现状,指出了天然气计量中存在的问题,剖析了产生这些问题的原因。在此基础上,提出了解决天然气计量问题的途径。     

我国天然气计量标准体系的建立和完善

文章介绍了国外天然气计量标准的发展和现状,阐明了我国天然气计量技术标准体系由单一计量标准到多种标准并存的发展历程,目前形成了完善的天然气计量标准体系,包括天然气计量系统标准、计量方法标准和能量计量标准,系列标准水平已达到国际接轨水平。     

天然气自动计量在配气站的应用

文章针对天然气计量影响因素比较繁多的具体情况,探讨了自动计量的必要与优势,也分析了存在的问题,认为天然气自动计量是目前天然气计量的优选方式,同时要正视孔板计量这种传统计量方式给我们带来很多不利因素,尽快实施"计量系数交接法",使我们的计量水平更上一个新台阶.     

多气源格局下天然气计量体系国内外进展

随着人们对环境问题的重视度越来越高,天然气作为一种清洁能源在我国化石能源消费体系中的占比也正在提升。近年来,在天然气消费过程中出现了不同气源的天然气增多、进口天然气比例上升等问题,形成了天然气管网多气源的格局。由于不同气源的天然气发热量存在明显差异,我国目前实行的天然气计量体系难以进行准确的贸易计量以及碳排放核算,需积极推进新型计量体系的建设。基于此,该文主要围绕国内外天然气计量体系的发展现状进行研究,介绍了体积计量、质量计量和能量计量3种计量方式及其测量原理,从技术标准、计量仪器、量值溯源方面对比分析了国内外现行的天然气计量技术,阐述我国在计量体系建设上开展的一系列工作,指出能量计量法从天然气的发热量出发,结合天然气的体积或质量流量,面对不同气源、不同品质的天然气能进行高效、准确的计量,是多气源天然气格局下的更公平、合理的计量方式。同时,指出我国在天然气气质分析设备、构建天然气分析溯源、管网中的核查技术等方面存在不足。     

提高天然气开采计量的准确性

文章介绍了气田天然气计量的现状及存在的难题,总结了有关天然气计量的经验,对提高气田计量水平提出了建议。     

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)。