The analysis of microstates in EEG signals is a crucial technique for understanding the spatiotemporal dynamics of brain electrical activity.Traditional methods such as Atomic Agglomerative Hierarchical Clustering(AAH...The analysis of microstates in EEG signals is a crucial technique for understanding the spatiotemporal dynamics of brain electrical activity.Traditional methods such as Atomic Agglomerative Hierarchical Clustering(AAHC),K-means clustering,Principal Component Analysis(PCA),and Independent Component Analysis(ICA)are limited by a fixed number of microstate maps and insufficient capability in cross-task feature extraction.Tackling these limitations,this study introduces a Global Map Dissimilarity(GMD)-driven density canopy K-means clustering algorithm.This innovative approach autonomously determines the optimal number of EEG microstate topographies and employs Gaussian kernel density estimation alongside the GMD index for dynamic modeling of EEG data.Utilizing this advanced algorithm,the study analyzes the Motor Imagery(MI)dataset from the GigaScience database,GigaDB.The findings reveal six distinct microstates during actual right-hand movement and five microstates across other task conditions,with microstate C showing superior performance in all task states.During imagined movement,microstate A was significantly enhanced.Comparison with existing algorithms indicates a significant improvement in clustering performance by the refined method,with an average Calinski-Harabasz Index(CHI)of 35517.29 and a Davis-Bouldin Index(DBI)average of 2.57.Furthermore,an information-theoretical analysis of the microstate sequences suggests that imagined movement exhibits higher complexity and disorder than actual movement.By utilizing the extracted microstate sequence parameters as features,the improved algorithm achieved a classification accuracy of 98.41%in EEG signal categorization for motor imagery.A performance of 78.183%accuracy was achieved in a four-class motor imagery task on the BCI-IV-2a dataset.These results demonstrate the potential of the advanced algorithm in microstate analysis,offering a more effective tool for a deeper understanding of the spatiotemporal features of EEG signals.展开更多
As a priority of China’s regional development strategy in recent years, promoting the ecological protection and high-quality development of the Yellow River Basin is one of the important tasks to boost the country’s...As a priority of China’s regional development strategy in recent years, promoting the ecological protection and high-quality development of the Yellow River Basin is one of the important tasks to boost the country’s economy and also the key to the development strategy in the central region at this stage. High-quality development of the Yellow River Basin based on the perspective of culture, sports, and tourism integration is significant for the regional ecological protection and economic revitalization. In order to measure the development of culture, sports, and tourism resources in the basin, the study applied the CRITIC model in Mathematical Statistics, the fuzzy comprehensive evaluation model, and the entropy weight TOPSIS analysis model. The results indicated that the development of the three resources in the basin varies from region to region, among which Shaanxi, Shandong, and Henan provinces have developed outstandingly while western provinces in China haven’t. In addition, this study identified the spatial geographic extent and analyzed the POI (points of interest) of culture, sports, tourism, and mixed resource based on the data analysis to explore the spatial distribution characteristics and trend of changes in the Yellow River Basin. The study also made suggestions for the development of culture, sports, and tourism resources in the basin from different perspectives based on the developed theoretical model, aiming to promote high-quality development of the area.展开更多
with the development of computer technology, foundry CAE technology has made rapid progress. Commercialsoftware packages of casting process simulation, therefore, have become more and more practical. This paper introd...with the development of computer technology, foundry CAE technology has made rapid progress. Commercialsoftware packages of casting process simulation, therefore, have become more and more practical. This paper introducesboth the recent developments and some applications of InteCAST software, a commercial numerical simulation softwarepackage for foundry industry, with more than 120 customers all over the world. The function modules of lnteCAST8.0 andsome new techniques, such as uneven mesh technology for mold filling simulation and numerical mouse technology fordata visualization, were introduced. Several applications on special castings such as investment casting, low pressure diecasting, and high pressure die casting, were given. These applications showed that the software can help engineers tooptimize casting process by forecasting casting defect.展开更多
Background There is an urgent need in clinical practice to measure the stress of parenting.The Caregiver Strain Questionnaire(CGSQ)was found to be useful to measure parenting stress,but it has not been validated among...Background There is an urgent need in clinical practice to measure the stress of parenting.The Caregiver Strain Questionnaire(CGSQ)was found to be useful to measure parenting stress,but it has not been validated among the Chinese population.Aims To assess the reliability and construct validity of the Chinese version of CGSQ among Chinese parents.Methods From 2016 to 2017,266 parents(patient group)with a child having DSM-5-defined attention deficit hyperactivity disorder(ADHD)(n=107)or autism spectrum disorder(ASD)(n=159)and 268 parents of healthy children(control group)were recruited to the present study in Kunming,Yunnan province.All the parents were asked to fill out the Chinese version of CGSQ.We conducted exploratory factor analysis and confirmatory factor analysis(CFA)to verify construct validity of CGSQ in both patient and control groups.Cronbach’s α coefficient as an index of internal consistency was assessed for each subscale.Fourteen days later,23 subjects filled out the scale again.Intra-class correlation coefficient was calculated to evaluate the test-retest reliability.Results(1)Cronbach’s alpha of the global scale was 0.901 for the control group and 0.952 for the patient group.The test-retest reliability for the whole scale was 0.890;(2)CFA indicated that the three-factor model had better fitting indices compared with the two-factor model in both groups.Besides,the fitting indices in the patient group were more favourable than those of the control group,withχ2/df=1.564,Goodness-of Fit Index=0.841,Comparative Fit Index=0.954,and root mean square error of approximation=0.065 for the patient group at three-factor model;(3)The caregiver strain of ASD parents was statistically higher than that of ADHD parents,and caregiver strain of ADHD parents was higher than that of control group.Conclusion These findings provide initial evidence to support the construct validity and reliability of CGSQ as a parenting stress measurement tool for Chinese parents,especially for parents of children with ADHD or ASD.展开更多
The development of Si-HfO_(2)/Yb_(2)Si_(2)O_(7)/Yb_(2)SiO_(5)environmental barrier coatings(EBCs)aims to improve the operational temperature and longevity of ceramic matrix composites(CMCs)in turbine environments.Neve...The development of Si-HfO_(2)/Yb_(2)Si_(2)O_(7)/Yb_(2)SiO_(5)environmental barrier coatings(EBCs)aims to improve the operational temperature and longevity of ceramic matrix composites(CMCs)in turbine environments.Nevertheless,several critical questions remain unanswered,including the oxidation mechanism of Si-HfO_(2)bond coating,the compatibility of its mixed thermally grown oxide(m-TGO)with adjacent layers during thermal cycling,and the evolution pattern of vertical mud-cracks that impact the overall performance in service.Using plasma spraying physical vapor deposition(PS-PVD),we fabricated these EBCs on a CMC substrate,and thermal cycling tests at 1400,1450,and 1500℃ revealed that their durability reached 200 h.m-TGO growth followed a parabolic model,with the oxygen diffusion activation energy being 133.69 kJ/mol between 1400 and 1450℃ and 101.47 kJ/mol from 1450 to 1500℃,emphasizing that the transport of molecular oxygen is key to controlling the oxidation of m-TGO in this EBC system.Although residual stresses and stored elastic strain energy build up between m-TGO and adjacent layers,especially around the cristobalite phase transition temperature,causing interlaminar crack formation in later thermal cycles,the stored elastic strain energy remains lower than that of the silicon oxide-thermally grown oxide(SiO_(2)-TGO)formed in Si bond coating system.In addition to[110]dislocations,(001)twinning and interaction zones between twinning and dislocations were discovered for the first time,driving the bifurcation of mud cracks.Notably,controlling the mud-crack density is vital for protection of Yb_(2)SiO_(5)layer,as bifurcated mud-crack tips may converge with adjacent mud-cracks.展开更多
This study aims to measure the regional difference in economic growth and the driving effect of export of coastal areas for inland provinces in China from the perspective of labor division.Embedded input and output da...This study aims to measure the regional difference in economic growth and the driving effect of export of coastal areas for inland provinces in China from the perspective of labor division.Embedded input and output data are adopted on the basis of the input-output theory for economic growth and trade accounting.Since China’s accession to WTO,vertical specialization across areas has been improved in general,but the areas differ widely in their participation in labor division in the global value chain(GVC)and national value chain(NVC).Different areas in China mainly rely on local production for economic growth,but engagement in GVC and NVC labor division is the major driver for the country’s rapid economic growth.Under the external impact,local economic growth has relied less on the outside,but more on local production since 2008.The driving effect of export of coastal areas for inland provinces is mainly reflected in agriculture,indicating that inland provinces and cities indirectly participate in international division of labor mainly by providing raw materials for production for eastern areas.This study,based on GVC and NVC integration and interaction,conducts in-depth research on the driving effect of export of coastal areas for the economic development of inland provinces,and offers a new perspective for studying the regional difference in economic growth in China.展开更多
Laser levitated in the air may open new application scenarios,such as quantum information processing,three-dimensional display,and ultra-sensitive gas sensing et al.However,the solid-state levitated laser is yet to be...Laser levitated in the air may open new application scenarios,such as quantum information processing,three-dimensional display,and ultra-sensitive gas sensing et al.However,the solid-state levitated laser is yet to be demonstrated.Here,we develop a nebulization method to fabricate colloidal quantum dots self-assembled microspheres,which can be levitated by photophoresis provided by continuous wave lasers and photoexcited by pulsed lasers.These levitated microspheres can serve as high-quality gain media and whispering gallery mode cavities simultaneously,allowing us to demonstrate the levitated solidstate laser for the first time.展开更多
基金funded by National Nature Science Foundation of China,Yunnan Funda-Mental Research Projects,Special Project of Guangdong Province in Key Fields of Ordinary Colleges and Universities and Chaozhou Science and Technology Plan Project of Funder Grant Numbers 82060329,202201AT070108,2023ZDZX2038 and 202201GY01.
文摘The analysis of microstates in EEG signals is a crucial technique for understanding the spatiotemporal dynamics of brain electrical activity.Traditional methods such as Atomic Agglomerative Hierarchical Clustering(AAHC),K-means clustering,Principal Component Analysis(PCA),and Independent Component Analysis(ICA)are limited by a fixed number of microstate maps and insufficient capability in cross-task feature extraction.Tackling these limitations,this study introduces a Global Map Dissimilarity(GMD)-driven density canopy K-means clustering algorithm.This innovative approach autonomously determines the optimal number of EEG microstate topographies and employs Gaussian kernel density estimation alongside the GMD index for dynamic modeling of EEG data.Utilizing this advanced algorithm,the study analyzes the Motor Imagery(MI)dataset from the GigaScience database,GigaDB.The findings reveal six distinct microstates during actual right-hand movement and five microstates across other task conditions,with microstate C showing superior performance in all task states.During imagined movement,microstate A was significantly enhanced.Comparison with existing algorithms indicates a significant improvement in clustering performance by the refined method,with an average Calinski-Harabasz Index(CHI)of 35517.29 and a Davis-Bouldin Index(DBI)average of 2.57.Furthermore,an information-theoretical analysis of the microstate sequences suggests that imagined movement exhibits higher complexity and disorder than actual movement.By utilizing the extracted microstate sequence parameters as features,the improved algorithm achieved a classification accuracy of 98.41%in EEG signal categorization for motor imagery.A performance of 78.183%accuracy was achieved in a four-class motor imagery task on the BCI-IV-2a dataset.These results demonstrate the potential of the advanced algorithm in microstate analysis,offering a more effective tool for a deeper understanding of the spatiotemporal features of EEG signals.
文摘As a priority of China’s regional development strategy in recent years, promoting the ecological protection and high-quality development of the Yellow River Basin is one of the important tasks to boost the country’s economy and also the key to the development strategy in the central region at this stage. High-quality development of the Yellow River Basin based on the perspective of culture, sports, and tourism integration is significant for the regional ecological protection and economic revitalization. In order to measure the development of culture, sports, and tourism resources in the basin, the study applied the CRITIC model in Mathematical Statistics, the fuzzy comprehensive evaluation model, and the entropy weight TOPSIS analysis model. The results indicated that the development of the three resources in the basin varies from region to region, among which Shaanxi, Shandong, and Henan provinces have developed outstandingly while western provinces in China haven’t. In addition, this study identified the spatial geographic extent and analyzed the POI (points of interest) of culture, sports, tourism, and mixed resource based on the data analysis to explore the spatial distribution characteristics and trend of changes in the Yellow River Basin. The study also made suggestions for the development of culture, sports, and tourism resources in the basin from different perspectives based on the developed theoretical model, aiming to promote high-quality development of the area.
文摘with the development of computer technology, foundry CAE technology has made rapid progress. Commercialsoftware packages of casting process simulation, therefore, have become more and more practical. This paper introducesboth the recent developments and some applications of InteCAST software, a commercial numerical simulation softwarepackage for foundry industry, with more than 120 customers all over the world. The function modules of lnteCAST8.0 andsome new techniques, such as uneven mesh technology for mold filling simulation and numerical mouse technology fordata visualization, were introduced. Several applications on special castings such as investment casting, low pressure diecasting, and high pressure die casting, were given. These applications showed that the software can help engineers tooptimize casting process by forecasting casting defect.
基金This work was supported by the National Natural Science Foundation of China(Grant No.81460218,30900488)National Key Technology Research and Development Program of the Ministry of Science and Technology of China(Grant No.2015BAI13B01).
文摘Background There is an urgent need in clinical practice to measure the stress of parenting.The Caregiver Strain Questionnaire(CGSQ)was found to be useful to measure parenting stress,but it has not been validated among the Chinese population.Aims To assess the reliability and construct validity of the Chinese version of CGSQ among Chinese parents.Methods From 2016 to 2017,266 parents(patient group)with a child having DSM-5-defined attention deficit hyperactivity disorder(ADHD)(n=107)or autism spectrum disorder(ASD)(n=159)and 268 parents of healthy children(control group)were recruited to the present study in Kunming,Yunnan province.All the parents were asked to fill out the Chinese version of CGSQ.We conducted exploratory factor analysis and confirmatory factor analysis(CFA)to verify construct validity of CGSQ in both patient and control groups.Cronbach’s α coefficient as an index of internal consistency was assessed for each subscale.Fourteen days later,23 subjects filled out the scale again.Intra-class correlation coefficient was calculated to evaluate the test-retest reliability.Results(1)Cronbach’s alpha of the global scale was 0.901 for the control group and 0.952 for the patient group.The test-retest reliability for the whole scale was 0.890;(2)CFA indicated that the three-factor model had better fitting indices compared with the two-factor model in both groups.Besides,the fitting indices in the patient group were more favourable than those of the control group,withχ2/df=1.564,Goodness-of Fit Index=0.841,Comparative Fit Index=0.954,and root mean square error of approximation=0.065 for the patient group at three-factor model;(3)The caregiver strain of ASD parents was statistically higher than that of ADHD parents,and caregiver strain of ADHD parents was higher than that of control group.Conclusion These findings provide initial evidence to support the construct validity and reliability of CGSQ as a parenting stress measurement tool for Chinese parents,especially for parents of children with ADHD or ASD.
基金support from the National Major Science and Technology Projects of China(No.Y2022-1II-0004-0013)the National Natural Science Foundation of China(No.52272065),and the Program of the China Scholarships Council(No.202206830106)+1 种基金performed at the Hefei Advanced Computing Center.Moreover,we appreciate eceshi(www.eceshi.com)for SEM-FIB analysiswe acknowledge the Center for Microscopy and Analysis at Nanjing University of Aeronautics and Astronautics for SEMEDS analysis.
文摘The development of Si-HfO_(2)/Yb_(2)Si_(2)O_(7)/Yb_(2)SiO_(5)environmental barrier coatings(EBCs)aims to improve the operational temperature and longevity of ceramic matrix composites(CMCs)in turbine environments.Nevertheless,several critical questions remain unanswered,including the oxidation mechanism of Si-HfO_(2)bond coating,the compatibility of its mixed thermally grown oxide(m-TGO)with adjacent layers during thermal cycling,and the evolution pattern of vertical mud-cracks that impact the overall performance in service.Using plasma spraying physical vapor deposition(PS-PVD),we fabricated these EBCs on a CMC substrate,and thermal cycling tests at 1400,1450,and 1500℃ revealed that their durability reached 200 h.m-TGO growth followed a parabolic model,with the oxygen diffusion activation energy being 133.69 kJ/mol between 1400 and 1450℃ and 101.47 kJ/mol from 1450 to 1500℃,emphasizing that the transport of molecular oxygen is key to controlling the oxidation of m-TGO in this EBC system.Although residual stresses and stored elastic strain energy build up between m-TGO and adjacent layers,especially around the cristobalite phase transition temperature,causing interlaminar crack formation in later thermal cycles,the stored elastic strain energy remains lower than that of the silicon oxide-thermally grown oxide(SiO_(2)-TGO)formed in Si bond coating system.In addition to[110]dislocations,(001)twinning and interaction zones between twinning and dislocations were discovered for the first time,driving the bifurcation of mud cracks.Notably,controlling the mud-crack density is vital for protection of Yb_(2)SiO_(5)layer,as bifurcated mud-crack tips may converge with adjacent mud-cracks.
文摘This study aims to measure the regional difference in economic growth and the driving effect of export of coastal areas for inland provinces in China from the perspective of labor division.Embedded input and output data are adopted on the basis of the input-output theory for economic growth and trade accounting.Since China’s accession to WTO,vertical specialization across areas has been improved in general,but the areas differ widely in their participation in labor division in the global value chain(GVC)and national value chain(NVC).Different areas in China mainly rely on local production for economic growth,but engagement in GVC and NVC labor division is the major driver for the country’s rapid economic growth.Under the external impact,local economic growth has relied less on the outside,but more on local production since 2008.The driving effect of export of coastal areas for inland provinces is mainly reflected in agriculture,indicating that inland provinces and cities indirectly participate in international division of labor mainly by providing raw materials for production for eastern areas.This study,based on GVC and NVC integration and interaction,conducts in-depth research on the driving effect of export of coastal areas for the economic development of inland provinces,and offers a new perspective for studying the regional difference in economic growth in China.
基金supported by the National Natural Science Foundation of China(No.52272167)the Innovation Program for Quantum Science and Technology(No.2021ZD0301603).carried out at the USTC Center for Micro and Nanoscale Research and Fabrication。
文摘Laser levitated in the air may open new application scenarios,such as quantum information processing,three-dimensional display,and ultra-sensitive gas sensing et al.However,the solid-state levitated laser is yet to be demonstrated.Here,we develop a nebulization method to fabricate colloidal quantum dots self-assembled microspheres,which can be levitated by photophoresis provided by continuous wave lasers and photoexcited by pulsed lasers.These levitated microspheres can serve as high-quality gain media and whispering gallery mode cavities simultaneously,allowing us to demonstrate the levitated solidstate laser for the first time.
