Accurate detection of exercise fatigue based on physiological signals is vital for reason-able physical activity.As a non-invasive technology,phonocardiogram(PCG)signals possess arobust capability to reflect cardiovas...Accurate detection of exercise fatigue based on physiological signals is vital for reason-able physical activity.As a non-invasive technology,phonocardiogram(PCG)signals possess arobust capability to reflect cardiovascular information,and their data acquisition devices are quiteconvenient.In this study,a novel hybrid approach of fractional Fourier transform(FRFT)com-bined with linear and discrete wavelet transform(DWT)features extracted from PCG is proposedfor PCG multi-class classification.The proposed system enhances the fatigue detection performanceby combining optimized FRFT features with an effective aggregation of linear features and DWTfeatures.The FRFT technique is employed to convert the 1-D PCG signal into 2-D image which issent to a pre-trained convolutional neural network structure,called VGG-16.The features from theVGG-16 were concatenated with the linear and DWT features to form fused features.The fusedfeatures are sent to support vector machine(SVM)to distinguish six distinct fatigue levels.Experi-mental results demonstrate that the proposed fused features outperform other feature combinationssignificantly.展开更多
Tungsten is a refractory metal with the highest melting point of all metals,which is considered as a promising candidate material for plasma-facing materials in the future fusion reactor.However,tungsten faces several...Tungsten is a refractory metal with the highest melting point of all metals,which is considered as a promising candidate material for plasma-facing materials in the future fusion reactor.However,tungsten faces several challenges from intrinsic embrittlement,irradiation embrittlement and recrystallization embrittlement during the operation of the fusion reactor.To satisfy the fusion engineering application,an advanced tungsten material with the fine grain and dense microstructure is required and developed.This paper briefly introduces the application background of the tungsten materials and mainly illus-trates a series of common techniques for manufacturing advance tungsten materials,such as powder preparation technologies,bulk densification techniques,continuous processing technologies and the coating and additive manufacturing technologies.Furthermore,the development prospects for manufacturing techniques of tungsten materials are also presented in the end.Considering the tungsten materials employed in the fusion engineering application,combining these scalable techniques of the wet-chemical method,pressureless sintering and continuous deformation processing techniques would be the possible research and development routes to realize the manufacture of the advanced tungsten materials.展开更多
基金the National Natural Sci-ence Foundation of China(No.62301056)the Fundamental Research Funds for Central Universities(No.2022QN005).
文摘Accurate detection of exercise fatigue based on physiological signals is vital for reason-able physical activity.As a non-invasive technology,phonocardiogram(PCG)signals possess arobust capability to reflect cardiovascular information,and their data acquisition devices are quiteconvenient.In this study,a novel hybrid approach of fractional Fourier transform(FRFT)com-bined with linear and discrete wavelet transform(DWT)features extracted from PCG is proposedfor PCG multi-class classification.The proposed system enhances the fatigue detection performanceby combining optimized FRFT features with an effective aggregation of linear features and DWTfeatures.The FRFT technique is employed to convert the 1-D PCG signal into 2-D image which issent to a pre-trained convolutional neural network structure,called VGG-16.The features from theVGG-16 were concatenated with the linear and DWT features to form fused features.The fusedfeatures are sent to support vector machine(SVM)to distinguish six distinct fatigue levels.Experi-mental results demonstrate that the proposed fused features outperform other feature combinationssignificantly.
基金the Magnetic Confinement Fusion Program of National Key Basic Research Project of China(Grant 2014GB121001B)National Natural Science Foundation of China(Grant 51474083,51574101,51674095 and 51675154)Program of Introducing Talents of Discipline to Universities of China(111 Project,Grant B18018).
文摘Tungsten is a refractory metal with the highest melting point of all metals,which is considered as a promising candidate material for plasma-facing materials in the future fusion reactor.However,tungsten faces several challenges from intrinsic embrittlement,irradiation embrittlement and recrystallization embrittlement during the operation of the fusion reactor.To satisfy the fusion engineering application,an advanced tungsten material with the fine grain and dense microstructure is required and developed.This paper briefly introduces the application background of the tungsten materials and mainly illus-trates a series of common techniques for manufacturing advance tungsten materials,such as powder preparation technologies,bulk densification techniques,continuous processing technologies and the coating and additive manufacturing technologies.Furthermore,the development prospects for manufacturing techniques of tungsten materials are also presented in the end.Considering the tungsten materials employed in the fusion engineering application,combining these scalable techniques of the wet-chemical method,pressureless sintering and continuous deformation processing techniques would be the possible research and development routes to realize the manufacture of the advanced tungsten materials.
