共查询到19条相似文献,搜索用时 140 毫秒
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采用原子荧光光谱法对土壤样品中硒进行测定,分析了影响测量不确定度的主要来源,对样品消解过程中的样品称量、消解、定容体积、曲线拟合等影响不确定度的分量进行了分析。结果表明,不确定度分量的主要来源为消解样品所引入的不确定度,其次为重复性试验工作曲线拟合产生的不确定度,其余因素的贡献均较小。按照JJF-1059-1999的规定对不确定度分量进行合成,最终给出扩展不确定度为0.087mg/kg,土壤硒含量测定结果的表示方式为(0.161±0.087)mg/kg(k=2)。 相似文献
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《分析仪器》2016,(1)
采用电感耦合等离子体发射光谱法(ICP-OES)和原子吸收光谱法(AAS)对测定铜矿石中铜元素进行系统的不确定度评定。建立两种方法测定铜矿石中铜元素的数学模型,分析不确定度的来源主要包括样品称量过程使用的天平、标准工作溶液配置过程所使用的量器、标准工作曲线拟合、测量重复性及试液定容体积等引入的不确定度分量,对引入的各不确定度分量进行量化,计算出各分量的不确定度,通过合成得到测量结果的合成不确定度、扩展不确定度及测试结果的报告形式。比较ICP-OES法和AAS法分别测定3个铜矿石样品中铜的不确定度,随着试样中铜元素浓度的增加,样品不确定度伴随增大趋势,两种方法所测定铜元素结果符合分析结果的相对偏差小于允许限为合格的要求。 相似文献
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通过对原子吸收光谱法测定铝合金中锌的不确定度的系统分析,阐述了测量结果不确定度主要来源于测量试液中锌的浓度、试液定容体积及样品质量产生的不确定度,并对这些分量进行了量化计算,最后计算出合成标准不确定度和扩展不确定度.同时通过评估,得出影响锌含量测定不确定度的主要因素是测量试液中锌浓度引起的不确定度. 相似文献
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New criterion for evaluating the aptitude of measurement systems in process capability determination
María Villeta Eva María Rubio Miguel Angel Sebastián Alfredo Sanz 《The International Journal of Advanced Manufacturing Technology》2010,50(5-8):689-697
In practice, carrying out statistical process control of manufacturing processes requires the use of measurement systems. These systems are not totally reliable because they are subject to inherent variability. This paper investigates the influence of measurement uncertainty on the analysis of manufacturing process capability. A new methodology is described that helps overcome the effect of measurement uncertainty in order to obtain a more accurate assessment of the capability of the production processes. This methodology presents a solution that ensures the metrological confirmation of the measurement processes, and it was developed for manufacturing processes centred at a nominal value and for off-centred processes. Moreover, an improved capability index integrated into the statistical process control is proposed for evaluating measurement systems. The index helps identify manufacturing process quality risks associated with uncertainty in measurement systems. 相似文献
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对形位误差测量不确定度影响因素的探讨 总被引:1,自引:0,他引:1
通过对形位误差测量整个过程进行分析,得出影响形位误差测量结果不确定度的主要因素,并简单概括了研究形位误差测量结果不确定度的一些难点。 相似文献
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采用电感耦合等离子体发射光谱法对葡萄酒中的铁含量进行了测定,分析了整个测量过程的不确定度来源,评定和合成了各个不确定度分量,得出葡萄酒中铁含量的的扩展不确定度为0.028mg/L。通过分析测量不确定度,能有效掌握测定结果的准确性和可信度,确保检验工作的质量。 相似文献
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Recent advances in versatile automated gauging have enabled accurate geometric tolerance assessment on the shop floor. This paper is concerned with the uncertainty evaluation associated with comparative coordinate measurement using the design of experiments (DOE) approach. It employs the Renishaw Equator which is a software-driven comparative gauge based on the traditional comparison of production parts to a reference master part. The fixturing requirement of each production part to the master part is approximately ±1 mm for a comparison process with an uncertainty of ±2 μm. Therefore, a number of experimental designs are applied with the main focus on the influence of part misalignment from rotation between master and measure coordinate frames on the comparator measurement uncertainty. Other factors considered include measurement mode mainly in scanning and touch-trigger probing (TTP) and alignment procedure used to establish the coordinate reference frame (CRF) with respect to the number of contact points used for each geometric feature measured. The measurement uncertainty analysis of the comparator technique used by the Equator gauge commences with a simple measurement task using a gauge block to evaluate the three-dimensional (3D) uncertainty of length comparative coordinate measurement influenced by an offset by tilt in one direction (two-dimensional angular misalignment). Then, a specific manufactured measurement object is employed so that the comparator measurement uncertainty can be assessed for numerous measurement tasks within a satisfactory range of the working volume of the versatile gauge. Furthermore, in the second case study, different types of part misalignment including both 2D and 3D angular misalignments are applied. The time required for managing the re-mastering process is also examined. A task specific uncertainty evaluation is completed using DOE. Also, investigating the effects of process variations that might be experienced by such a device in workshop environments. It is shown that the comparator measurement uncertainties obtained by all the experiments agree with system features under specified conditions. It is also demonstrated that when the specified conditions are exceeded, the comparator measurement uncertainty is associated with the measurement task, the measurement strategy used, the feature size, and the magnitude and direction of offset angles in relation to the reference axes of the machine. In particular, departures from the specified part fixturing requirement of Equator have a more significant effect on the uncertainty of length measurement in comparator mode and a less significant effect on the diameter measurement uncertainty for the specific Equator and test conditions. 相似文献
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为了掌握熔石英样品在紫外波段的吸收特性,研究了精确评估激光量热仪测量不确定度的方法。介绍了激光量热仪的吸收测量原理,选用指数法对吸收测量数据进行了拟合;通过分析各吸收率测量结果的影响分量,建立了测量不确定度评估模型;对各输入量的估计值以及估计值的标准不确定度逐一进行计算,并对影响吸收率测量结果的拟合计算参数A、γ进行了修正。考虑背景温度漂移对被测样品温度测量的影响,利用Matlab编程分析了线性、非线性温度漂移对吸收计算结果的影响,获得其相对标准不确定度及相对扩展不确定度分别为2.6%和5.2%。最后,更换熔石英基底并进行多次吸收测量,计算了吸收率10次测量结果平均值的相对标准不确定度为2.3%,相对扩展不确定度为4.6%,与评估结果基本相同。 相似文献
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成像光谱仪辐射定标影响量的测量链与不确定度 总被引:2,自引:8,他引:2
分析了成像光谱仪遥感观测数据中包含的地物光谱特征、仪器参数和大气传输特性等的信息结构。研究了成像光谱仪辐射定标的物理过程和测量链,应用1993年国际标准化组织(ISO)颁布的《测量不确定度表示指南》,分析了辐射定标11项影响量的测量不确定度和合成标准不确定度。遥感辐射定标的绝对精度就是不确定度。辐射定标需要辐射标准、积分球光源、光谱辐射计以及遥感器上设置星上定标装置等专用设备和技术,并经过多级测量链的测试过程才能完成。光谱辐照度标准的不确定度在3%~5%,辐射定标中其它影响量的测量不确定度限制在1%~2%,成像光谱仪辐射定标的绝对精度才能达到5%~8%,这需要相当好的仪器设备和光辐射测试技术。 相似文献