A bread-and-butter model was proposed to evaluate the weighing uncertainty of gas standard materials by combining the preparation principles of gas standard materials by using weighing method with the differential alg...A bread-and-butter model was proposed to evaluate the weighing uncertainty of gas standard materials by combining the preparation principles of gas standard materials by using weighing method with the differential algorithms of multivariate function.The model was applied to calculate the content of CO in 10 μmol/mol CO standard materials prepared by weighing method and to evaluate its weighing uncertainty.The evaluation processes are simple and the result is reasonable.This modle is suitable for the evaluation of the uncertainty of gas standard materials in industrial processes.展开更多
The contents of As,Cd,Hg and Pb in 27 Chinese medicinal herbs were determined by ICP-MS with microwave assisted digestion.Cluster analysis was applied to study the distribution characteristics of As,Cd,Hg and Pb in di...The contents of As,Cd,Hg and Pb in 27 Chinese medicinal herbs were determined by ICP-MS with microwave assisted digestion.Cluster analysis was applied to study the distribution characteristics of As,Cd,Hg and Pb in different kinds of Chinese medical herbs from different sources.The result of cluster analysis showed that the contents of As,Cd,Hg and Pb from different sources were significantly different.It is helpful in the quality control and source identification of Chinese medicinal herbs.展开更多
文摘A bread-and-butter model was proposed to evaluate the weighing uncertainty of gas standard materials by combining the preparation principles of gas standard materials by using weighing method with the differential algorithms of multivariate function.The model was applied to calculate the content of CO in 10 μmol/mol CO standard materials prepared by weighing method and to evaluate its weighing uncertainty.The evaluation processes are simple and the result is reasonable.This modle is suitable for the evaluation of the uncertainty of gas standard materials in industrial processes.
文摘The contents of As,Cd,Hg and Pb in 27 Chinese medicinal herbs were determined by ICP-MS with microwave assisted digestion.Cluster analysis was applied to study the distribution characteristics of As,Cd,Hg and Pb in different kinds of Chinese medical herbs from different sources.The result of cluster analysis showed that the contents of As,Cd,Hg and Pb from different sources were significantly different.It is helpful in the quality control and source identification of Chinese medicinal herbs.
