To effectively assess the extent of the mycotoxin contamination of grapes,a method was developed to analyze 22 mycotoxins by ultra-high-performance liquid chromatography coupled with quadrupole/orbitrap high-resolutio...To effectively assess the extent of the mycotoxin contamination of grapes,a method was developed to analyze 22 mycotoxins by ultra-high-performance liquid chromatography coupled with quadrupole/orbitrap high-resolution mass spectrometry(UPLC-Q-Orbitrap HRMS).Samples were extracted and purified using the QuEChERS(quick,easy,cheap,effective,rugged,and safe)procedure.The extracts were separated on a BEH Shield C18 column(100 mm×2.1 mm,1.7μm),using methanol and water with 0.1%formic acid solution and 2 mmol/L ammonium acetate as the mobile phases.The quantification was performed according to a matrix-matched external standard method.There was a good linear relationship within the respective mass concentration ranges of 22 mycotoxins;the correlation coefficients were not less than 0.9981.The limit of quantification was 0.3-10.0μg/kg.Mycotoxin recovery ranged from 68.6%to 109.0%,with a relative standard deviation of 1.28%-12.80%.The method is simple,rapid,highly sensitive,and accurate,making it useful for screening grapes for common and emerging mycotoxins.展开更多
A mobile fiber-optic laser-induced breakdown spectrometer(FO-LIBS) prototype was developed to rapidly detect a large quantity of steel material online and quantitatively analyze the trace elements in a large-diameter ...A mobile fiber-optic laser-induced breakdown spectrometer(FO-LIBS) prototype was developed to rapidly detect a large quantity of steel material online and quantitatively analyze the trace elements in a large-diameter steel tube.Twenty-four standard samples and a polynomial fitting method were used to establish calibration curve models.The R^2 factors of the calibration curves were all above 0.99,except for Cu,indicating the elements’ strong self-absorption effect.Five special steel materials were rapidly detected in the steel mill.The average absolute errors of Mn,Cr,Ni,V,Cu,and Mo in the special steel materials were 0.039,0.440,0.033,0.057,0.003,and0.07 wt%,respectively,and their average relative errors fluctuated from 2.9% to 15.7%.The results demonstrated that the performance of this mobile FO-LIBS prototype can be compared with that of most conventional LIBS systems,but the more robust and flexible characteristics of the FO-LIBS prototype provide a feasible approach for promoting LIBS from the laboratory to the industry.展开更多
基于Randolph-Quiggin非线性管土作用模型,借助ABAQUS Subroutine功能中的User Defined Element(UEL)拓展模块创建钢悬链线立管触地单元,研究了顶端垂荡激励下立管触地段动力响应特性。通过与模型试验结果比较分析,验证了开发的数值分...基于Randolph-Quiggin非线性管土作用模型,借助ABAQUS Subroutine功能中的User Defined Element(UEL)拓展模块创建钢悬链线立管触地单元,研究了顶端垂荡激励下立管触地段动力响应特性。通过与模型试验结果比较分析,验证了开发的数值分析模型的合理性,并讨论了其相较传统线性管土作用模型体现出的优势。开展参数敏感性分析,深入探讨了立管顶端垂荡幅值及周期对沟槽形状、立管位移及弯矩响应等的影响效应。展开更多
In recent years,a laser-induced breakdown spectrometer(LIBS)combined with machine learning has been widely developed for steel classification.However,the much redundant information of LIBS spectra increases the comput...In recent years,a laser-induced breakdown spectrometer(LIBS)combined with machine learning has been widely developed for steel classification.However,the much redundant information of LIBS spectra increases the computation complexity for classification.In this work,restricted Boltzmann machines(RBM)and principal component analysis(PCA)were used for dimension reduction of datasets,respectively.Then,a support vector machine(SVM)was adopted to process feature information.Two models(RBM-SVM and PCA-SVM)are compared in terms of performance.After optimization,the accuracy of the RBM-SVM model can achieve 100%,and the maximum dimension reduction time is 33.18 s,which is nearly half of that of the PCA model(53.19 s).These results preliminarily indicate that LIBS combined with RBM-SVM has great potential in the real-time classification of steel.展开更多
基金supported by Science and Technology Program of the State Administration for Market Regulation of China (2020MK014).
文摘To effectively assess the extent of the mycotoxin contamination of grapes,a method was developed to analyze 22 mycotoxins by ultra-high-performance liquid chromatography coupled with quadrupole/orbitrap high-resolution mass spectrometry(UPLC-Q-Orbitrap HRMS).Samples were extracted and purified using the QuEChERS(quick,easy,cheap,effective,rugged,and safe)procedure.The extracts were separated on a BEH Shield C18 column(100 mm×2.1 mm,1.7μm),using methanol and water with 0.1%formic acid solution and 2 mmol/L ammonium acetate as the mobile phases.The quantification was performed according to a matrix-matched external standard method.There was a good linear relationship within the respective mass concentration ranges of 22 mycotoxins;the correlation coefficients were not less than 0.9981.The limit of quantification was 0.3-10.0μg/kg.Mycotoxin recovery ranged from 68.6%to 109.0%,with a relative standard deviation of 1.28%-12.80%.The method is simple,rapid,highly sensitive,and accurate,making it useful for screening grapes for common and emerging mycotoxins.
基金supported by National Natural Science Foundation of China(Nos.61705064,11647122)the Natural Science Foundation of Hubei Province(Nos.2018CFB773,2018CFB672)the Project of the Hubei Provincial Department of Education(No.T201617)。
文摘A mobile fiber-optic laser-induced breakdown spectrometer(FO-LIBS) prototype was developed to rapidly detect a large quantity of steel material online and quantitatively analyze the trace elements in a large-diameter steel tube.Twenty-four standard samples and a polynomial fitting method were used to establish calibration curve models.The R^2 factors of the calibration curves were all above 0.99,except for Cu,indicating the elements’ strong self-absorption effect.Five special steel materials were rapidly detected in the steel mill.The average absolute errors of Mn,Cr,Ni,V,Cu,and Mo in the special steel materials were 0.039,0.440,0.033,0.057,0.003,and0.07 wt%,respectively,and their average relative errors fluctuated from 2.9% to 15.7%.The results demonstrated that the performance of this mobile FO-LIBS prototype can be compared with that of most conventional LIBS systems,but the more robust and flexible characteristics of the FO-LIBS prototype provide a feasible approach for promoting LIBS from the laboratory to the industry.
文摘基于Randolph-Quiggin非线性管土作用模型,借助ABAQUS Subroutine功能中的User Defined Element(UEL)拓展模块创建钢悬链线立管触地单元,研究了顶端垂荡激励下立管触地段动力响应特性。通过与模型试验结果比较分析,验证了开发的数值分析模型的合理性,并讨论了其相较传统线性管土作用模型体现出的优势。开展参数敏感性分析,深入探讨了立管顶端垂荡幅值及周期对沟槽形状、立管位移及弯矩响应等的影响效应。
基金supported by National Natural Science Foundation of China(No.61705064)the Natural Science Foundation of Hubei Province(No.2021CFB607)+1 种基金the Natural Science Foundation of Xiaogan City(No.XGKJ2021010003)the Project of the Hubei Provincial Department of Education(No.T201617)。
文摘In recent years,a laser-induced breakdown spectrometer(LIBS)combined with machine learning has been widely developed for steel classification.However,the much redundant information of LIBS spectra increases the computation complexity for classification.In this work,restricted Boltzmann machines(RBM)and principal component analysis(PCA)were used for dimension reduction of datasets,respectively.Then,a support vector machine(SVM)was adopted to process feature information.Two models(RBM-SVM and PCA-SVM)are compared in terms of performance.After optimization,the accuracy of the RBM-SVM model can achieve 100%,and the maximum dimension reduction time is 33.18 s,which is nearly half of that of the PCA model(53.19 s).These results preliminarily indicate that LIBS combined with RBM-SVM has great potential in the real-time classification of steel.
