Using the operator correspondence of the real and fictious modes in the thermo entangled state representation, wesolve the quantum master equation describing the diffusion channel and obtain the Kraus operator-sum rep...Using the operator correspondence of the real and fictious modes in the thermo entangled state representation, wesolve the quantum master equation describing the diffusion channel and obtain the Kraus operator-sum representation ofits analytical solution. we find that the pure coherent states evolve into the new mixed thermal superposed states in thediffusion channel. Also, we investigate the statistical properties of the initial coherent states and their entropy evolutions inthe diffusion channel, and find that the entropy evolutions are only related to the decay time and without the amplitudes ofthe initial coherent states.展开更多
Pyro-breaker is a fast-responding and high-reliable explosive-driven circuit breaker,which has been applied in several quench protection systems,such as International Thermonuclear Experimental Reactor and Experimenta...Pyro-breaker is a fast-responding and high-reliable explosive-driven circuit breaker,which has been applied in several quench protection systems,such as International Thermonuclear Experimental Reactor and Experimental Advanced Superconducting Tokamak.As an indispensable back-up switch,Pyro-breaker guarantees the reliability and safety of the system and avoids tremendous loss when quench happens.Electrical contact,a crucial part of an electrical device greatly determines the steady current capacity of a Pyro-breaker.However,due to the complexity of the model and the deficiency knowledge of the microstate of contact areas,an accurate calculation for contact resistance is difficult to acquire.A study of electrical contact in the design of a Pyro-breaker has been presented in this paper.An engineering calculation method is verified with experiments.Parameters are fitted for the presented model,which will be a significant theoretical basis for the future designing.展开更多
Biomass-to-ethylene glycol is an effective means to achieve high-value utilisation of cellulose but is hindered by low conversion efficiency and poor catalyst activity and stability.Glucose and cellobiose are derivati...Biomass-to-ethylene glycol is an effective means to achieve high-value utilisation of cellulose but is hindered by low conversion efficiency and poor catalyst activity and stability.Glucose and cellobiose are derivatives of cellulose conversion to ethylene glycol,and it is found that studying the reaction process of both can help to understand the reaction mechanism of cellulose.It is desirable to develop a reusable,highly active catalyst to convert cellulose into ethylene glycol.This ideal catalyst might have one or more active sites described the conversion steps above.Here,we discuss the catalyst development of celluloseto-ethylene glycol,including tungsten,tin,lanthanide,and other transition metal catalysts,and special attention is given to the reaction mechanism and kinetics for preparing ethylene glycol from cellulose,and the economic advantages of biomass-to-ethylene glycol are briefly introduced.The insights given in this review will facilitate further development of efficient catalysts,for addressing the global energy crisis and climate change related to the use of fossil fuels.展开更多
Liquid metal(LM)and liquid metal alloys(LMs)possess unique physicochemical features,which have become emerging and functionalized materials that are attractive applicants in various fields.Herein,uniform LM nanodrople...Liquid metal(LM)and liquid metal alloys(LMs)possess unique physicochemical features,which have become emerging and functionalized materials that are attractive applicants in various fields.Herein,uniform LM nanodroplets armored by carbon dots(LMD@CDs)were prepared and exhibited high colloidal stability in various solvents,as well as water.After optimization,LMD@CDs can be applied as functional additives for the 3D/4D printing of hydrogel and cross-linked resin through digital light processing(DLP).The light absorption of LMD@CDs not only improved the printing accuracy,but also led to the cross-linking density differential during the post-curing process.Base on the cross-linking density differential of soft hydrogel and photothermal performance of the LM,the 3D printed objects can exhibit stimulus responses to both water and laser irradiation.Additionally,the CDs shell and LM core of LMD@CDs provide the printed objects interesting photoluminescence and electric conductivity capabilities,respectively.We deduce this versatile 3D/4D printing system would provide a new platform for the preparation of multi-functional and stimuli-responsive advance materials.展开更多
The Sulige gas field is a typical low-pressure low-permeability tight sandstone gas reservoir. The reservoir has poor seepage capacity, strong heterogeneity, high mineralization of formation water and extremely scarce...The Sulige gas field is a typical low-pressure low-permeability tight sandstone gas reservoir. The reservoir has poor seepage capacity, strong heterogeneity, high mineralization of formation water and extremely scarce water resources on the site. These unfavorable factors have brought great difficulties to the on-site mining process. Now, a nano-composite green environmental protection slick water fracturing fluid system CQFR can be quickly dissolved because of the larger specific surface area, and the small molecular size makes the damage to the reservoir less than 5%, and the average drag reduction effect can reach more than 73%. It can quickly and well dissolve and maintain performance under high salinity conditions and fracturing flowback fluids. It responds well to the complex reservoir conditions on the construction site and makes the flowback fluid recyable, which greatly reduces the consumption of water resources on the construction site and effectively improves the construction efficiency and economic benefits.展开更多
This study is aimed to classify degrees of diaphragma sellae (DS) descent into sella turcica according to the surgical field block caused by the descent and to construct predictive imaging criteria for the degree of d...This study is aimed to classify degrees of diaphragma sellae (DS) descent into sella turcica according to the surgical field block caused by the descent and to construct predictive imaging criteria for the degree of descent,and in addition,to determine whether there is any correlation between the degree of DS descent and the operative outcome (in the form of cerebrospinal fluid leak and/or presence of residual tumor).Totally,72 patients were enrolled in our study.Their clinical and radiological data as well as the high definition videos of operations were retrospectively reviewed.The degree of DS descent during the operation was classified into five degrees according to surgical field block caused by the descent.We investigated the correlation between these five degrees and the clinical findings,radiological findings as well as the surgical outcomes.We found that the most important determining factors of DS descent degree were the volume and the height of the tumor portion above diaphragma opening.On the other hand,the total tumor volume,the maximum tumor height and the morphological pattern according to Wilson's system (modified from Hardy) had no statistically significant correlation with DS degree of descent.Presence of residual tumor on postoperative magnetic resonance images was significantly correlated with Wilson's classification and with supradiaphragmatic tumor height.On the other hand,cerebrospinal fluid leak showed no statistically significant difference between variable degrees of DS descent.Volumetric data of the tumor portion above the diaphragma opening are more important than morphological data for prediction of surgical field block caused by descended DS.While DS prolapse significantly increases the difficulty of the operative procedure,residual tumor presence is mainly dependent on morphological classification,especially cavernous sinus invasion.展开更多
In order to test the superconducting magnet performance for the Comprehensive Research Facility for Fusion Technology(CRAFT)project of China,a power supply converter needs to be designed.In this paper,short circuits u...In order to test the superconducting magnet performance for the Comprehensive Research Facility for Fusion Technology(CRAFT)project of China,a power supply converter needs to be designed.In this paper,short circuits upstream and downstream of the direct current(DC)reactor are analyzed,and the thyristor style and the parallel number are determined by the limit analysis of junction temperature and fault current I^2t.On this basis,the over current and voltage verification of fast fuse are finished to protect the thyristor at fault cases by considering the short circuit of the bridge arm.Then,the resistor and capacitor parameters of thyristor snubber are committed to decreasing the reverse over voltage.These analysis results will be used as the preliminary design of high power magnet converter for CRAFT.展开更多
The multispectral remote sensing image(MS-RSI)is degraded existing multi-spectral camera due to various hardware limitations.In this paper,we propose a novel core tensor dictionary learning approach with the robust mo...The multispectral remote sensing image(MS-RSI)is degraded existing multi-spectral camera due to various hardware limitations.In this paper,we propose a novel core tensor dictionary learning approach with the robust modified Gaussian mixture model for MS-RSI restoration.First,the multispectral patch is modeled by three-order tensor and high-order singular value decomposition is applied to the tensor.Then the task of MS-RSI restoration is formulated as a minimum sparse core tensor estimation problem.To improve the accuracy of core tensor coding,the core tensor estimation based on the robust modified Gaussian mixture model is introduced into the proposed model by exploiting the sparse distribution prior in image.When applied to MS-RSI restoration,our experimental results have shown that the proposed algorithm can better reconstruct the sharpness of the image textures and can outperform several existing state-of-the-art multispectral image restoration methods in both subjective image quality and visual perception.展开更多
Massive Open Online Course(MOOC)has become a popular way of online learning used across the world by millions of people.Meanwhile,a vast amount of information has been collected from the MOOC learners and institutions...Massive Open Online Course(MOOC)has become a popular way of online learning used across the world by millions of people.Meanwhile,a vast amount of information has been collected from the MOOC learners and institutions.Based on the educational data,a lot of researches have been investigated for the prediction of the MOOC learner’s final grade.However,there are still two problems in this research field.The first problem is how to select the most proper features to improve the prediction accuracy,and the second problem is how to use or modify the data mining algorithms for a better analysis of the MOOC data.In order to solve these two problems,an improved random forests method is proposed in this paper.First,a hybrid indicator is defined to measure the importance of the features,and a rule is further established for the feature selection;then,a Clustering-Synthetic Minority Over-sampling Technique(SMOTE)is embedded into the traditional random forests algorithm to solve the class imbalance problem.In experiment part,we verify the performance of the proposed method by using the Canvas Network Person-Course(CNPC)dataset.Furthermore,four well-known prediction methods have been applied for comparison,where the superiority of our method has been proved.展开更多
A study was conducted on the newly promulgated key protected wild plants distributed in the Dabie Mountains National Nature Reserve in Hubei in 2021.According to statistics,Dabie Mountains National Nature Reserve of H...A study was conducted on the newly promulgated key protected wild plants distributed in the Dabie Mountains National Nature Reserve in Hubei in 2021.According to statistics,Dabie Mountains National Nature Reserve of Hubei Province has a total of 41 species of wild plants under national key protection,including 7 species in the first class and 34 species in the second class.Among them,6 are cultivated species,4 in the first class,and 2 species in the second class.The characteristics of Chinese key protected wild plants in the Dabie Mountains National Nature Reserve in Hubei Province were analyzed.展开更多
基金Collaborative Innovation Project of University,Anhui Province(Grant No.GXXT-2022-088).
文摘Using the operator correspondence of the real and fictious modes in the thermo entangled state representation, wesolve the quantum master equation describing the diffusion channel and obtain the Kraus operator-sum representation ofits analytical solution. we find that the pure coherent states evolve into the new mixed thermal superposed states in thediffusion channel. Also, we investigate the statistical properties of the initial coherent states and their entropy evolutions inthe diffusion channel, and find that the entropy evolutions are only related to the decay time and without the amplitudes ofthe initial coherent states.
文摘Pyro-breaker is a fast-responding and high-reliable explosive-driven circuit breaker,which has been applied in several quench protection systems,such as International Thermonuclear Experimental Reactor and Experimental Advanced Superconducting Tokamak.As an indispensable back-up switch,Pyro-breaker guarantees the reliability and safety of the system and avoids tremendous loss when quench happens.Electrical contact,a crucial part of an electrical device greatly determines the steady current capacity of a Pyro-breaker.However,due to the complexity of the model and the deficiency knowledge of the microstate of contact areas,an accurate calculation for contact resistance is difficult to acquire.A study of electrical contact in the design of a Pyro-breaker has been presented in this paper.An engineering calculation method is verified with experiments.Parameters are fitted for the presented model,which will be a significant theoretical basis for the future designing.
基金supported by the National Natural Science Foundation of China(51976112,52206264)special Project Fund of“Taishan Scholar”of Shandong Province(tsqn202103066)Natural Science Foundation of Shandong Province(ZR2022ME109)。
文摘Biomass-to-ethylene glycol is an effective means to achieve high-value utilisation of cellulose but is hindered by low conversion efficiency and poor catalyst activity and stability.Glucose and cellobiose are derivatives of cellulose conversion to ethylene glycol,and it is found that studying the reaction process of both can help to understand the reaction mechanism of cellulose.It is desirable to develop a reusable,highly active catalyst to convert cellulose into ethylene glycol.This ideal catalyst might have one or more active sites described the conversion steps above.Here,we discuss the catalyst development of celluloseto-ethylene glycol,including tungsten,tin,lanthanide,and other transition metal catalysts,and special attention is given to the reaction mechanism and kinetics for preparing ethylene glycol from cellulose,and the economic advantages of biomass-to-ethylene glycol are briefly introduced.The insights given in this review will facilitate further development of efficient catalysts,for addressing the global energy crisis and climate change related to the use of fossil fuels.
基金The financial support from the National Natural Science Foundation of China(Grant No.51973201,U1804128,to X.P.Grant No.52173209,to Y.H.)+4 种基金the 111 Project(D18023,to X.P.)the National Science Foundation for Young Scientists of China(Grant No.22105179,to G.S.)the National Key R&D Program of China(2017YFB0307600,to M.L)China Postdoctoral Science Foundation(2020M682317,to X.Z)Scientific&technological research projects in Henan Province(222102520009,to X.Q.)
文摘Liquid metal(LM)and liquid metal alloys(LMs)possess unique physicochemical features,which have become emerging and functionalized materials that are attractive applicants in various fields.Herein,uniform LM nanodroplets armored by carbon dots(LMD@CDs)were prepared and exhibited high colloidal stability in various solvents,as well as water.After optimization,LMD@CDs can be applied as functional additives for the 3D/4D printing of hydrogel and cross-linked resin through digital light processing(DLP).The light absorption of LMD@CDs not only improved the printing accuracy,but also led to the cross-linking density differential during the post-curing process.Base on the cross-linking density differential of soft hydrogel and photothermal performance of the LM,the 3D printed objects can exhibit stimulus responses to both water and laser irradiation.Additionally,the CDs shell and LM core of LMD@CDs provide the printed objects interesting photoluminescence and electric conductivity capabilities,respectively.We deduce this versatile 3D/4D printing system would provide a new platform for the preparation of multi-functional and stimuli-responsive advance materials.
文摘The Sulige gas field is a typical low-pressure low-permeability tight sandstone gas reservoir. The reservoir has poor seepage capacity, strong heterogeneity, high mineralization of formation water and extremely scarce water resources on the site. These unfavorable factors have brought great difficulties to the on-site mining process. Now, a nano-composite green environmental protection slick water fracturing fluid system CQFR can be quickly dissolved because of the larger specific surface area, and the small molecular size makes the damage to the reservoir less than 5%, and the average drag reduction effect can reach more than 73%. It can quickly and well dissolve and maintain performance under high salinity conditions and fracturing flowback fluids. It responds well to the complex reservoir conditions on the construction site and makes the flowback fluid recyable, which greatly reduces the consumption of water resources on the construction site and effectively improves the construction efficiency and economic benefits.
文摘This study is aimed to classify degrees of diaphragma sellae (DS) descent into sella turcica according to the surgical field block caused by the descent and to construct predictive imaging criteria for the degree of descent,and in addition,to determine whether there is any correlation between the degree of DS descent and the operative outcome (in the form of cerebrospinal fluid leak and/or presence of residual tumor).Totally,72 patients were enrolled in our study.Their clinical and radiological data as well as the high definition videos of operations were retrospectively reviewed.The degree of DS descent during the operation was classified into five degrees according to surgical field block caused by the descent.We investigated the correlation between these five degrees and the clinical findings,radiological findings as well as the surgical outcomes.We found that the most important determining factors of DS descent degree were the volume and the height of the tumor portion above diaphragma opening.On the other hand,the total tumor volume,the maximum tumor height and the morphological pattern according to Wilson's system (modified from Hardy) had no statistically significant correlation with DS degree of descent.Presence of residual tumor on postoperative magnetic resonance images was significantly correlated with Wilson's classification and with supradiaphragmatic tumor height.On the other hand,cerebrospinal fluid leak showed no statistically significant difference between variable degrees of DS descent.Volumetric data of the tumor portion above the diaphragma opening are more important than morphological data for prediction of surgical field block caused by descended DS.While DS prolapse significantly increases the difficulty of the operative procedure,residual tumor presence is mainly dependent on morphological classification,especially cavernous sinus invasion.
基金supported by the National Key R&D Program of China(No.2017YFE0300504)Comprehensive Research Facility for Fusion Technology(No.2018-00005273-01-001228).
文摘In order to test the superconducting magnet performance for the Comprehensive Research Facility for Fusion Technology(CRAFT)project of China,a power supply converter needs to be designed.In this paper,short circuits upstream and downstream of the direct current(DC)reactor are analyzed,and the thyristor style and the parallel number are determined by the limit analysis of junction temperature and fault current I^2t.On this basis,the over current and voltage verification of fast fuse are finished to protect the thyristor at fault cases by considering the short circuit of the bridge arm.Then,the resistor and capacitor parameters of thyristor snubber are committed to decreasing the reverse over voltage.These analysis results will be used as the preliminary design of high power magnet converter for CRAFT.
基金This work was supported by the Project of Shandong Province Higher Educational Science and Technology Program[KJ2018BAN047,Geng,L.]National Natural Science Foundation of China[61801222,Fu,P.]+2 种基金Fundamental Research Funds for the Central Universities[30919011230,Fu,P.]Science and Technology Innovation Program for Distributed Young Talents of Shandong Province Higher Education Institutions[2019KJN045,Guo,Q.]Shandong Provincial Key Laboratory of Network Based Intelligent Computing[http://nbic.ujn.edu.cn/].
文摘The multispectral remote sensing image(MS-RSI)is degraded existing multi-spectral camera due to various hardware limitations.In this paper,we propose a novel core tensor dictionary learning approach with the robust modified Gaussian mixture model for MS-RSI restoration.First,the multispectral patch is modeled by three-order tensor and high-order singular value decomposition is applied to the tensor.Then the task of MS-RSI restoration is formulated as a minimum sparse core tensor estimation problem.To improve the accuracy of core tensor coding,the core tensor estimation based on the robust modified Gaussian mixture model is introduced into the proposed model by exploiting the sparse distribution prior in image.When applied to MS-RSI restoration,our experimental results have shown that the proposed algorithm can better reconstruct the sharpness of the image textures and can outperform several existing state-of-the-art multispectral image restoration methods in both subjective image quality and visual perception.
基金supported by the National Natural Science Foundation of China under Grant No.61801222in part supported by the Fundamental Research Funds for the Central Universities under Grant No.30919011230in part supported by the Jiangsu Provincial Department of Education Degree and Graduate Education Research Fund under Grant No.JGZD18_012.
文摘Massive Open Online Course(MOOC)has become a popular way of online learning used across the world by millions of people.Meanwhile,a vast amount of information has been collected from the MOOC learners and institutions.Based on the educational data,a lot of researches have been investigated for the prediction of the MOOC learner’s final grade.However,there are still two problems in this research field.The first problem is how to select the most proper features to improve the prediction accuracy,and the second problem is how to use or modify the data mining algorithms for a better analysis of the MOOC data.In order to solve these two problems,an improved random forests method is proposed in this paper.First,a hybrid indicator is defined to measure the importance of the features,and a rule is further established for the feature selection;then,a Clustering-Synthetic Minority Over-sampling Technique(SMOTE)is embedded into the traditional random forests algorithm to solve the class imbalance problem.In experiment part,we verify the performance of the proposed method by using the Canvas Network Person-Course(CNPC)dataset.Furthermore,four well-known prediction methods have been applied for comparison,where the superiority of our method has been proved.
基金Supported by 2022 Capacity Building Project of Hubei Dabie Mountains National Nature Reserve(20120220002)Joint Open Fund for Hubei Key Laboratory of Economic Forest Germplasm Improvement and Resources Comprehensive Utilization and Hubei Collaborative Innovation Center for the Characteristic Resources Exploitation of Dabie Mountains(202020604).
文摘A study was conducted on the newly promulgated key protected wild plants distributed in the Dabie Mountains National Nature Reserve in Hubei in 2021.According to statistics,Dabie Mountains National Nature Reserve of Hubei Province has a total of 41 species of wild plants under national key protection,including 7 species in the first class and 34 species in the second class.Among them,6 are cultivated species,4 in the first class,and 2 species in the second class.The characteristics of Chinese key protected wild plants in the Dabie Mountains National Nature Reserve in Hubei Province were analyzed.
