彩色亮度计光源色度的不确定度分析

JJG 211-2005亮度计检定规程已颁布实施,它同时囊括了亮度计和彩色亮度计的检定,增加了光源色度参数的校准.在实施实践中,校准彩色亮度计所用的标准反射色板采用了色差计校准用的一套标准反射色板,校准时的标准值取标准反射色板溯源证书中的A/2,0/45的数据.从彩色亮度计中光源色度参数的实验数据,以及对其测量结果的不确定度分析,均证明新规程校准方法正确,而共用标准反射色板亦可行,校准效果良好.     

彩色亮度计光源色度的不确定度分析

JJG211—2005亮度计检定规程已颁布实施,它同时囊括了亮度计和彩色亮度计的检定,增加了光源色度参数的校准。在实施实践中,校准彩色亮度计所用的标准反射色板采用了色差计校准用的一套标准反射色板,校准时的标准值取标准反射色板溯源证书中的A／2,0／45的数据。从彩色亮度计中光源色度参数的实验数据,以及对其测量结果的不确定度分析,均证明新规程校准方法正确,而共用标准反射色板亦可行,校准效果良好。     

CR-400型色差仪测量结果的不确定度评定

文章针对CR-400型色差仪的校准结果进行不确定度评定分析,评定刺激值Y的不确定度后,通过公式计算得出色品坐标x,y的不确定度。     

普通照明用非定向自镇流LED灯色品容差的测试方法和实验装置

文章详细介绍了普通照明用非定向自镇流LED灯相关色温和色品容差的测试方法和实验装置,并根据普通照明用非定向自镇流LED灯色品容差的测量不确定度来源,对单个样品进行了不确定度评定。文章所述评定方法是灯具/光源质检机构在监督检查中可重点参考的方法,同时,此方法可以指导生产厂家对其产品的色品容差进行有效质控。     

JJG229-2010给出的不确定度评定方法会导致错误选用检定标准

JJG229-2010《工业铂、铜热电阻》给出的测量不确定度评定方法,没有认识到只有测量值正强相关,相关系数为+1或很接近+1,其测量不确定度才能代数和合成。仅凭测量值相关就认为其测量不确定度为代数和合成,评定出的标准不确定度,仅为正确的标准不确定度的十分之一。显然,据此评定结果选用检定标准必定是错误的,会使得量值传递的测量不确定度不满足要求。     

水平尺分度值误差测量结果的不确定度评定

为了水平尺分度值误差测量结果的不确定度评定合理,基于用水平尺校准规范中的数学模型,对其测量不确定度来源进行分析,列出了方差、灵敏系数及标准不确定度的计算公式,从而给出了水平尺分度值误差测量的合成标准不确定度和扩展不确定度。     

标准粘度液测量结果不确定度分析及评定

本文分析了标准粘度液检测结果测量不确定度的主要来源,介绍了标准粘度液测量不确定度的评定步骤和方法,给出了评定结果。     

基于虚拟测量样本的锅炉效率不确定度评定

对于复杂的间接测量问题,采用不确定度传递律进行合成不确定度的评定有时较为困难,针对这种情况,给出了合成标准不确定评定的新方法,即将输入量的测量值看作随机变量,并以输入量的估计值和标准不确定度作为分布参数的正态分布随机变量,将该随机变量离散成容量足够大的输入样本,通过测量模拟计算得到被测量的虚拟分布样本,进而利用该分布样本进行合成不确定度的评定.采用这种方法对国家标准中的误差分析算例进行不确定度评定,得到的结果与用国家标准给出的误差分析数据相近.     

焦度计测量顶焦度的不确定度评定

分析了焦度计测量顶焦度不确定度的主要来源,讨论了标准不确定度、合成不确定度和扩展不确定度的评定方法,并给出了焦度计测量顶焦度不确定度的评定结果。     

Excel在数字表示值误差测量结果不确定度评定中的应用

给出了数字表示值误差测量结果不确定度评定,同时采用Excel电子表格辅助评定,解决了评定中的所有计算问题,从而提供了一种进行测量不确定度评定的方便而且快捷的方法。     

全国非接触式汽车速度计比对的研究

由中国计量科学研究院作为主导实验室的全国非接触式汽车速度计比对于2018年完成。作为机动车测速计量领域的首个固定地点的现场比对,参比实验室29家,其中27家为已建标的省级计量技术机构,全部比对结果为满意。介绍了比对的基本情况、技术方案,研究了比对方法和不确定度来源,提出了测速计量现场比对的特殊性,分析了比对结果。     

Coordinate-Based Evaluation of Two Dimensional Artefact Calibration Value as the Reference Standards for Coordinate Measuring Machines

Two dimensional standards are important materials which are used in the calibration and the verification of coordinate measuring machines. In several countries, the national metrology institutes or accredit laboratories provide the calibration services of the two dimensional standards such as ball plates, hole plates and grid plates. The metrological equivalence of the measurement standards among the calibration providers is validated through the key comparison program. In the previous key comparison for a ball plate and a hole plate, the equivalences among the participants’ calibration results were verified on the distances between the No. 1 ball/hole (i.e., the origins of the workpiece coordinates) and other balls/holes on the plates respectively. The essential measurands of the two dimensional standards are the coordinates of the feature points, however, the measurement equivalences on them have not been verified. In this study, the authors propose the coordinates-based evaluation of the reference values and their uncertainty in two dimensional standard calibration comparison.     

DJ2级经纬仪竖盘指标自动补偿误差不确定度的评定

计量标准处于量值传递体系的中间环节,对于保障国家计量单位制的统一和量值传递的一致性及准确性起着十分重要的作用。根据JJF 1033-2016《计量标准考核规范》的要求,开展经纬仪检定装置的建标工作,需要提供检定或校准结果的不确定度评定。而经纬仪竖盘指标自动补偿误差为光学经纬仪的必检项目,因此需要评定其测得值的不确定度,根据GUM法,分析影响经纬仪竖盘指标自动补偿误差的不确定度来源,合成标准不确定度,同时根据自由度查表得到包含因子,最后给出扩展不确定度,为单位开展经纬仪检定装置的建标工作打下基础,同时也为开展经纬仪检定业务的单位起到借鉴作用。     

计量中回归模型参数值及其不确定度评估

针对计量领域中广泛应用的数据回归处理方法,阐述了在基于正态分布噪声条件下,最小二乘法与贝叶斯推断法用于回归模型参数估计以及相应不确定度评估的过程。GUM系列不确定度评估准则中没有明确指出如何对回归参数进行不确定度评估,同时有些回归模型也无法唯一地转化为相应的测量方程。通过计量校准的实例说明了如何处理相应参数的确定等问题,以此说明2种方法的相同与不同之处。最小二乘方法计算简单直接且便于使用;而基于贝叶斯推断的方法则能充分利用计量校准中的经验和历史数据等信息,但由于其参数后验分布计算通常较为复杂,需采用马尔科夫链-蒙特卡罗(MCMC)法通过数值计算得到关注参数的结果。     

Experimental comparison of 241Am-Be neutron fluence energy distributions

(241)Am-Be(alpha,n) neutron sources provide one of the most commonly used neutron fields for routine calibration of neutron sensitive devices. The neutron energy distribution of the IRSN standard (241)Am-Be source was measured in the energy region above 1.65 MeV using a BC501A proton-recoil liquid scintillator. The experimental data were compared to the ISO-recommended neutron energy distribution for an (241)Am-Be source. Some differences in shape were observed, with large variations mainly within the energy interval 3-6 MeV and around 8 MeV. Within the framework of a collaboration between three national metrological institutes (PTB, Germany; NPL, UK and LNE-IRSN, France), the neutron energy distributions of (241)Am-Be sources at each laboratory have been compared. The IRSN-BC501A proton-recoil scintillator was used to measure all the sources. The results show different energy distributions a priori influenced by the origin of the source, i.e. the manufacturing process. The maximum deviation observed for the integral dose equivalent, in the measured BC501A energy range, is within the 4% uncertainty recommended by ISO standard 8529-2 to allow for variations of the neutron spectrum among different (241)Am-Be sources. However, knowledge of the energy distribution of an (241)Am-Be source provides a way to reduce the uncertainty in the dose equivalent rate delivered by such a source.     

白光干涉测量系统的测量不确定度评定

白光干涉测量系统(white-light interference system, WLIS)广泛用于微纳米表面形貌的精密测量,其测量不确定度评定是研究白光干涉测量系统计量特性的一项重要工作。基于微纳米线间隔和台阶,建立了WLIS测量表面形貌时的测量模型,明确了测量不确定度来源;以5000nm的线间隔和180nm的台阶高度为例,利用WLIS进行了测量,并分析WLIS的测量重复性、光学组件特性、传感器特性、运动模块性能、测试方法及环境等因素产生的不确定度分量,最终评定该WLIS测量线间隔和台阶高度的合成测量不确定度分别为21nm和0.4nm。对WLIS的不确定度评定确保了其测量结果的准确性、溯源性,并提出了提高系统整体计量特性的途径。     

Colorimetry-based retardation measurement method with white-light interference

A colorimetry-based retardation measurement (CBRM) method is presented. The specimen, between crossed polarizers, is illuminated with a white-light source. The retardation that is due to the birefringence of the specimen produces a white-light interference color. The x, y chromaticity coordinates of the color produced are measured with a spectrophotometer. The resulting x, y values are compared with a retardation x, y database that we obtained by measuring the retardation with an accurate Senarmont compensator and the x, y chromaticity values along the length of a 0-4-order quartz wedge. The technique was validated by the measurement of a variety of retardation plates. The retardation accuracy (mean error) of the CBRM method is shown to be 3.6 nm. The resolution is +/-0.2 nm, and the measurement range is 5-2150 nm. The method substitutes for a polariscope and eliminates errors associated with quarter-wave plates. The CBRM method does not utilize any moving parts and thus is fast and can be automated.