氧弹热量计热容量测量结果的不确定度评定

文章主要介绍了氧弹热量计热容量测量结果的不确定度评定.     

氧弹热量计热容量测量值的相对扩展不确定度的评定

氧弹热量计是用于测定固体、液体燃料热值的计量仪器,本文介绍了氧弹热量计的测量原理,对测量值进行相对不确定度的分析与评定。     

氧弹热量计测量苯甲酸热值及其示值误差的不确定度评定

以苯甲酸标准物质为例,根据热值和热值示值误差的数学模型,逐步评定了热量计热容量、热值和热值示值误差的不确定度。研究了热量计温升不确定对热值不确定度的影响;探讨了标准物质热值不确定度对热值示值误差不确定度的影响。苯甲酸热值不确定度U（Q）为40J/g（k＝2）,苯甲酸热值示值误差的不确定度U（ΔQ）为30J/g（ k＝2）。评定结果对于煤炭等燃料热值不确定度评定,氧弹热量计仪器准确度评定和计量检定规程的修订具有指导意义。     

氧弹热量计热值误差测量不确定度评定

依据JJG672-2001《氧弹热量计》检定规程和JJF1059-1999《测量不确定度评定与表示》,本文对使用苯甲酸检定自动热量计的热值误差的测量不确定度的来源进行了分析,从而给出了使用苯甲酸检定自动热量计热值误差的测量结果的合成不确定和扩展不确定度。     

真空绝热式氧弹热量计的研制与分析

为了更好的满足能源物资的贸易结算、清洁利用以及碳排放核算等需求,提升可燃物质发热量的测量精度和准确度,研制了基于真空杜瓦瓶技术的高精度绝热式氧弹热量计。介绍了热量计的基本结构和工作原理,提出了与之适用的测试流程和试验方法。燃烧热物质以美国标准与技术研究院(NIST)的苯甲酸(SRM39j)为例,测试了热量计的热容量和燃烧物的发热量,评定了发热量示值误差不确定度,讨论了温度电路的线性度、发热量的有效范围和热量计的环境适应性。试验数据表明,热容量的相对标准偏差为0.047%,3个月变化量为0.138%,苯甲酸发热量示值误差为17.8 J·g^-1,测量扩展不确定度为27.8 J(k=2),温度电路的线性度为0.999 93,有效测试范围为15 800～37 000 J,热量计环境适应性有待加强。     

工业氧弹热量计电能标定装置研究

针对采用二级苯甲酸标定工业氧弹热量计热容量的不足,提出一种电能标定装置标定工业氧弹热量计的方法。先采用NIST苯甲酸(39j)标定的精密氧弹热量计,然后用精密氧弹热量计测试电能标定装置释放的电热量QE,并统计其消耗的电能量W,再综合推导出电热修正系数α。修正后的电能标定装置标定工业氧弹热量计热容量,相对标准偏差为0.11%,所释放的电热量相对扩展不确定度为0.09%(k=2),符合二级苯甲酸的技术要求。该电能标定装置精度高,操作方便,环保且经济,可用于工业氧弹热量计的日常标定工作。     

氧弹热量计热值误差测量结果的不确定度评定

本文通过对一定量的燃烧热标准物质苯甲酸在热量计的氧弹内燃烧放出的热量的测量结果,探讨了其不确定度的评定.     

氧弹安全性能综合测试仪研制

介绍了国家质检总局科技计划项目《氧弹式热量计氧弹安全性能综合测试仪》的立项背景、研究意义及研制过程、测试仪的工作原理,进行了示值误差测量结果的不确定度评定计算,对创新点进行了说明和总结。     

异辛烷热值标准物质

采用国家固体燃烧热基准,即电能标定的等温式氧弹热量计,为异辛烷热值标准物质定值。通过电能标定热量计的热容量,使热值结果溯源到温度、电流、时间和质量等国际单位上。采用自制的聚乙烯胶囊盛装异辛烷,避免了样品挥发引入的质量测量和不完全燃烧的系统误差。异辛烷热值标准物质在标准状态下的高位发热量为47777 J/g,扩展不确定度为52 J/g（扩展因子k=2）。     

燃烧热测量不确定度的评定

文章按照JJF1059-1999的要求,参照GB213-1996的测量方法建立了利用氧弹热量计燃烧热的不确定度测量模型,对燃烧产物为二氧化碳和水的样品的燃烧热测量不确定度进行了分析.     

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.     

卧式金属罐容量的测量结果不确定度

本文根据多年的实践检定经验 ,参照JJF1 0 59- 1 999《测量不确定度评定与表示》以及《测量不确定度表达 1 0讲》 ,对卧式金属罐容量的测量结果不确定度进行了评定。     

盐酸浓度不确定度的评估

通过对盐酸浓度标定的过程分析，找出影响结果的各个分量，进行不确定度的评定，按照计量技术规范给出标准的表示法。     

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。