固体吸附/热脱附-气相色谱法测定环境空气中苯系物的不确定度评定

建立固体吸附/热脱附-气相色谱法测定环境空气中苯系物的不确定度评定方法,分析测定过程中不确定度的来源,进行各不确定度分量的评估,并给出合成相对标准不确定度和扩展不确定度。     

气体分析仪测量不确定度的分析

参照国际标准化组织颁布的"1S0 6143:2001(E)"标准方法,利用相对法求出回归方程,对环境气体分析仪进行了不确定度评定。分析了校准曲线图上每个校准点处的标准物质的不确定度和仪器响应值对回归直线参数的不确定度贡献,并将这些不确定度合成,给出参数的不确定度以及气体分析仪测定气体样品的不确定度。     

预冷冻浓缩系统与气相色谱-质谱法测定空气中苯的测量不确定度评定

根据 Top－down技术中的控制图法，运用预冷冻浓缩系统与气相色谱－质谱联用对苯标准样气进行多次测定。通过计算和评定，得出当苯的测定浓度为100×10^－9时，不确定度为5．1×10^－9。     

空气质量自动监测二氧化硫不确定度分析

不确定度是反映某一测量方法,在一定置信概率条件下测量所产生的不确定量。根据测量原理建立数学模型,分析各种不确定度分量的来源,评定标准不确定度,确定合成不确定度和扩展不确定度,通过不确定影响分量的分析,找出影响测量结果的最大不确定度分量,重点控制其分量,保证测量的准确性和精度,同时也可通过重新评估显著性不确定分量,找出方法存在的不足和问题,提出逐步控制不确定分量的步骤和方法,改善测量方法和手段提高测量准确性和精度,不断减少测量的不确定量。     

Modification of uncertainty analysis in adapted material flow analysis: Case study of nitrogen flows in the Day-Nhue River Basin,Vietnam

Nitrogen flows impacted by human activities in the Day-Nhue River Basin in northern Vietnam have been modeled using adapted material flow analysis (MFA). This study introduces a modified uncertainty analysis procedure and its importance in MFA. We generated a probability distribution using a Monte Carlo simulation, calculated the nitrogen budget for each process and then evaluated the plausibility under three different criterion sets. The third criterion, with one standard deviation of the budget value as the confidence interval and 68% as the confidence level, could be applied to effectively identify hidden uncertainties in the MFA system. Sensitivity analysis was conducted for revising parameters, followed by the reassessment of the model structure by revising equations or flow regime, if necessary. The number of processes that passed the plausibility test increased from five to nine after reassessment of model uncertainty with a greater model quality. The application of the uncertainty analysis approach to this case study revealed that the reassessment of equations in the aquaculture process largely changed the results for nitrogen flows to environments. The significant differences were identified as increased nitrogen load to the atmosphere and to soil/groundwater (17% and 41%, respectively), and a 58% decrease in nitrogen load to surface water. Thus, modified uncertainty analysis was considered to be an important screening system for ensuring quality of MFA modeling.     

火焰原子吸收法测定水样铅含量的不确定度评定

实验室认可和资质认定都要求检测实验室具备评定测量不确定度的能力,现依据JJF1059-1999《测量不确定度评定与表示》,对火焰原子吸收法测定水样中铅含量进行不确定度评估,分析测定过程中不确定度来源,量化不确定度分量,求出合成不确定度和扩展不确定度,给出测定结果的表示式。