The elemental distribution within the large-dimension rare earth inclusion in steels was studied through analysis on plane distribution of elements by EPMA (Electron Probe Microanalyzer). The kinetics and mechanism of...The elemental distribution within the large-dimension rare earth inclusion in steels was studied through analysis on plane distribution of elements by EPMA (Electron Probe Microanalyzer). The kinetics and mechanism of formation of RE inclusion were discussed, taking 5CrNiMo steel with the addition of RE and other microalloying elements as example. RE inclusions nucleate on oxides and sulphides with high melting point and grow up separately, then integrated by relatively high surface activity, which is a particular characteristic of RE elements, in liquid phase and during the course of solidification. Finally, the fine and dispersed RE inclusions merge and grow into a large-dimension one.展开更多
This paper proposes the corrected likelihood ratio test （LRT） and large-dimensional trace criterion to test the independence of two large sets of multivariate variables of dimensions P1 and P2 when the dimensions P ...This paper proposes the corrected likelihood ratio test （LRT） and large-dimensional trace criterion to test the independence of two large sets of multivariate variables of dimensions P1 and P2 when the dimensions P = P1 ＋ P2 and the sample size n tend to infinity simultaneously and proportionally. Both theoretical and simulation results demonstrate that the traditional X2 approximation of the LRT performs poorly when the dimension p is large relative to the sample size n, while the corrected LRT and large-dimensional trace criterion behave well when the dimension is either small or large relative to the sample size. Moreover, the trace criterion can be used in the case of p 〉 n, while the corrected LRT is unfeasible due to the loss of definition.展开更多
This paper introduces a high precision 7m laser measuring instrument developedby the anthors and its operating principle,and systematically analyses the errors havinginfluence on the performance of the measuring instr...This paper introduces a high precision 7m laser measuring instrument developedby the anthors and its operating principle,and systematically analyses the errors havinginfluence on the performance of the measuring instrument.Error analysis and actualverification indicate that all the characteristics reached or exceeded the original designspecifications.展开更多
文摘The elemental distribution within the large-dimension rare earth inclusion in steels was studied through analysis on plane distribution of elements by EPMA (Electron Probe Microanalyzer). The kinetics and mechanism of formation of RE inclusion were discussed, taking 5CrNiMo steel with the addition of RE and other microalloying elements as example. RE inclusions nucleate on oxides and sulphides with high melting point and grow up separately, then integrated by relatively high surface activity, which is a particular characteristic of RE elements, in liquid phase and during the course of solidification. Finally, the fine and dispersed RE inclusions merge and grow into a large-dimension one.
基金supported by National Natural Science Foundation of China(Grant Nos.11101181,11171057,11171058 and 11071035)Research Fund for the Doctoral Program of Higher Education of China(Grant No.20110061120005)+1 种基金NECT-11-0616,PCSIRTthe Fundamental Research Funds for the Central Universities
文摘This paper proposes the corrected likelihood ratio test （LRT） and large-dimensional trace criterion to test the independence of two large sets of multivariate variables of dimensions P1 and P2 when the dimensions P = P1 ＋ P2 and the sample size n tend to infinity simultaneously and proportionally. Both theoretical and simulation results demonstrate that the traditional X2 approximation of the LRT performs poorly when the dimension p is large relative to the sample size n, while the corrected LRT and large-dimensional trace criterion behave well when the dimension is either small or large relative to the sample size. Moreover, the trace criterion can be used in the case of p 〉 n, while the corrected LRT is unfeasible due to the loss of definition.
文摘This paper introduces a high precision 7m laser measuring instrument developedby the anthors and its operating principle,and systematically analyses the errors havinginfluence on the performance of the measuring instrument.Error analysis and actualverification indicate that all the characteristics reached or exceeded the original designspecifications.
