At present,physical education is listed as the key teaching.This paper introduces the importance of physical education in Colleges and universities,analyzes the current situation of College Physical Education and expl...At present,physical education is listed as the key teaching.This paper introduces the importance of physical education in Colleges and universities,analyzes the current situation of College Physical Education and explores the improvement strategies of College Physical Education at this stage.展开更多
The“New Medical Education”is a new requirement for the development of medical education in the new era.As a key and core element of the construction of the“New Medical Education,”the engagement in teaching work of...The“New Medical Education”is a new requirement for the development of medical education in the new era.As a key and core element of the construction of the“New Medical Education,”the engagement in teaching work of university teachers is a key issue that determines the level of teaching development of university teachers and affects the quality of talent cultivation in universities.Using the literature review method,this study analyzed 39 relevant literatures retrieved from China National Knowledge Infrastructure(CNKI)from 1997 to 2023.The concept,connotation,current situation,influencing factors,and improvement strategies of teaching engagement by university teachers were reviewed and summarized.The results showed that the issue of teaching engagement by university teachers has not received high attention in the field of higher education,especially in higher medical education,which has not yet been reported.Although the overall number of literature is not large,some of the conclusions have important implications for the next research on the influencing factors and mechanisms of double-qualified teacher engagement in higher medical colleges.展开更多
To improve the comfortable physical environment for square in severe cold regions' rural areas. This paper applies the methods of questionnaires,field testing and statistical analysis to compare and analyze two di...To improve the comfortable physical environment for square in severe cold regions' rural areas. This paper applies the methods of questionnaires,field testing and statistical analysis to compare and analyze two different square cases of Qingyunpu in Liaoning Province,and conclude the main factors which affect the physical environmental comfort. The improvement strategies for physical environment of rural square are put forward from the aspects of site selection,road position,orientation,landscape design,and ground pavement material selection,aiming to provide the design basis for the physical environment of square in severe cold regions' rural areas.展开更多
Enhancing the nutritional quality of food crops is a way to improve human nutrition and health. Grain protein content ( GPC ) is an important nutritional quality trait for rice and many other crops. Therefore, it wi...Enhancing the nutritional quality of food crops is a way to improve human nutrition and health. Grain protein content ( GPC ) is an important nutritional quality trait for rice and many other crops. Therefore, it will be very significant to increase GPC and improve rice quality. This paper mainly reviewed the genetic studies GPC in rice, mapping and cloning of QTLs and genes associated with GPC. However, little is known about the molecular mechanism and gene function related to GPC in rice. Thus, here we put forward the genetic strategy by gene pyramiding or molecular marker assisted selection to improve GPC and nutritional quality in rice. This review could provide important information for genetic improvement of grain nutritional quality of rice.展开更多
This article discusses the various blood interactions that may occur with various types of nano drug-loading systems. Nanoparticles enter the blood circulation as foreign objects. On the one hand, they may cause a ser...This article discusses the various blood interactions that may occur with various types of nano drug-loading systems. Nanoparticles enter the blood circulation as foreign objects. On the one hand, they may cause a series of inflammatory reactions and immune reactions, resulting in the rapid elimination of immune cells and the reticuloendothelial system, affecting their durability in the blood circulation. On the other hand, the premise of the drug-carrying system to play a therapeutic role depends on whether they cause coagulation and platelet activation, the absence of hemolysis and the elimination of immune cells. For different forms of nano drug-carrying systems, we can find the characteristics, elements and coping strategies of adverse blood reactions that we can find in previous researches. These adverse reactions may include destruction of blood cells, abnormal coagulation system, abnormal effects of plasma proteins, abnormal blood cell behavior, adverse immune and inflammatory reactions, and excessive vascular stimulation. In order to provide help for future research and formulation work on the blood compatibility of nano drug carriers.展开更多
English online learning has been common trend in the world, how to teach and learn effectively in EFL classes through online environment is an urgent study. The purpose of the study to analyze the factors of affecting...English online learning has been common trend in the world, how to teach and learn effectively in EFL classes through online environment is an urgent study. The purpose of the study to analyze the factors of affecting the effectiveness of online teaching and learning in EFL classes in college. We build up a three-dimensional model in the perspective of teacher, learner and technology. And we propose the strategies of improving the effectiveness of online teaching and learning in EFL classes in college in the dimensions of teacher, learner and technology.展开更多
Recent advances in stem cell technologies have opened new avenues for the treatment of a number of diseases still lacking effective therapeutic options.Cell transplantation has emerged as among the most promising clin...Recent advances in stem cell technologies have opened new avenues for the treatment of a number of diseases still lacking effective therapeutic options.Cell transplantation has emerged as among the most promising clinical intervention for disorders such as injuries,diabetes,liver diseases, neurodegeneration and heart failure (Lee et al., 2013; Forbes and Rosenthal, 2014; Tabar and Studer, 2014).展开更多
The development course of China's meteorological movie and television was analyzed firstly, and then the improvement strategies of meteorological movie and television services facing public needs were put forward bas...The development course of China's meteorological movie and television was analyzed firstly, and then the improvement strategies of meteorological movie and television services facing public needs were put forward based on the statistical results of a meteorological service questionnaire.展开更多
With the consistent development of society,economy and culture,people have had increasing requirements on high-quality public spaces.However,current landscapes have been far away from equal and just for various causes...With the consistent development of society,economy and culture,people have had increasing requirements on high-quality public spaces.However,current landscapes have been far away from equal and just for various causes,and to explore the realization of landscape justice has become a key concern in the fi eld of landscape architecture.Greenway as a linear space with bigger scale and strong connectivity in the current green space inventory is easier to update,so it provides a new direction for realizing landscape justice.This paper analyzed the existing greenway policies,design and planning,and problems in using,provided corresponding strategies for improvement,so as to achieve the landscape justice,provide new ideas and instructions for the present greenway construction and maintenance.展开更多
Research self-efficacy is of great significance for teachers to improve their interest and achievements in scientific research.In this study,261 elementary teachers were surveyed through online questionnaires to under...Research self-efficacy is of great significance for teachers to improve their interest and achievements in scientific research.In this study,261 elementary teachers were surveyed through online questionnaires to understand their research self-efficacy.The results showed that most elementary teachers have good research self-efficacy;education background,years of teaching,research environment,and attitude toward research all had influence on the research self-efficacy of elementary teachers.Based on this situation,schools should make efforts,such as improving communication,providing financial support,establishing a scientific research support center,and helping teachers under unfavorable situations.For elementary teachers,they should realize the importance of education research and improve their research literacy。展开更多
Objective To investigate influence of immunosuppression strategy optimization on outcomes of renal transplant recipients in the last decades. Methods Data from 404 renal transplant recipients from Jan. 1st,2001 to Dec...Objective To investigate influence of immunosuppression strategy optimization on outcomes of renal transplant recipients in the last decades. Methods Data from 404 renal transplant recipients from Jan. 1st,2001 to Dec. 31st,2010 were analyzed retrospectively. The pa-展开更多
Potassium-ion batteries(PIBs)have been considered as promising candidates in the post-lithium-ion battery era.Till now,a large number of materials have been used as electrode materials for PIBs,among which vanadium ox...Potassium-ion batteries(PIBs)have been considered as promising candidates in the post-lithium-ion battery era.Till now,a large number of materials have been used as electrode materials for PIBs,among which vanadium oxides exhibit great potentiality.Vanadium oxides can provide multiple electron transfers during electrochemical reactions because vanadium possesses a variety of oxidation states.Meanwhile,their relatively low cost and superior material,structural,and physicochemical properties endow them with strong competitiveness.Although some inspiring research results have been achieved,many issues and challenges remain to be further addressed.Herein,we systematically summarize the research progress of vanadium oxides for PIBs.Then,feasible improvement strategies for the material properties and electrochemical performance are introduced.Finally,the existing challenges and perspectives are discussed with a view to promoting the development of vanadium oxides and accelerating their practical applications.展开更多
In this paper, the fixed-time event-triggered obstacle avoidance consensus control for a multi-AUV time-varying formation system in a 3D environment is presented by using an improved artificial potential field and lea...In this paper, the fixed-time event-triggered obstacle avoidance consensus control for a multi-AUV time-varying formation system in a 3D environment is presented by using an improved artificial potential field and leader-follower strategy(IAPF-LF). Firstly, the proposed fixed-time control can achieve the desired multi-AUV formation within a fixed settling time in any initial system state. Secondly, an event-triggered communication strategy is developed to govern the communication among AUVs, and the communication energy consumption can be decremented. The time-varying formation obstacle avoidance control algorithm based on IAPF-LF is designed to avoid static and dynamic obstacles, the desired formation is maintained in the presence of external disturbances, and there is no Zeno behavior under the fixed-time event-triggered consensus control strategy.The stability of the system is proved by the Lyapunov function and inequality scaling. Finally, simulation examples and water pool experiments are reported to verify the performance of the proposed theoretical algorithms.展开更多
Using sunlight to drive chemical reactions via photocatalysis is paramount for a sustainable future.Among several photocatalysts,employing layered double hydrides(LDH) for photocatalytic application is most straightfo...Using sunlight to drive chemical reactions via photocatalysis is paramount for a sustainable future.Among several photocatalysts,employing layered double hydrides(LDH) for photocatalytic application is most straightforward and desirable owing to their distinctive two-dimensional(2D) lamellar structure and optical attributes.This article reviews the advancements in bimetallic/trimetallic LDHs and various strategies to achieve high efficiency toward an outstanding performing photocatalyst.Firstly,the tuning of LDH components that control the electro nic and structural properties is explained.The tu ning obtained through the adoption,combination,and incorporation of different cations and anions is also explained.The progress of modification methods,such as the adoption of different morphologies,delamination,and defect engineering towards enhanced photocatalytic activities,is discussed in the mainstream.The band engineering,structural characteristics,and redox tuning are further deliberated to maximize solar energy harvesting for different photocatalytic applications.Finally,the progress obtained in forming hierarchical heterostructures through hybridization with other semiconductors or conducting materials is systematically disclosed to get maximum photocatalytic performance.Moreover,the structural changes during the in-situ synthesis of LDH and the stability of LDH-based photocatalysts are deliberated.The review also summarizes the improvements in LDH properties obtained through modification tactics and discusses the prospects for future energy and environmental applications.展开更多
There are two categories of tropical crop machinery. One comprises operation machinery that is used for planting, managing and harvesting tropical crops, while the other comprises process machinery for processing ... There are two categories of tropical crop machinery. One comprises operation machinery that is used for planting, managing and harvesting tropical crops, while the other comprises process machinery for processing tropical crops. Tropical crop machinery is distinguished from other agricultural machinery by the special crops that such machinery cultivates and processes.……展开更多
Because of its controlled power factor and no commutation failure,current source converter(CSC)made up of reverse-blocking IGCTs(RB-IGCTs)offers broad application prospects in the field of HVDC system.Valve voltage an...Because of its controlled power factor and no commutation failure,current source converter(CSC)made up of reverse-blocking IGCTs(RB-IGCTs)offers broad application prospects in the field of HVDC system.Valve voltage and power operating range as the most important operating characteristics should be paid attention to but they are always contradictory.First,the relationship between valve voltage and modulation index is obtained.In particular,valve voltage of converter under the three typical modulation methods is compared,analyzed,and verified.Second,with the help of the independent control strategy and coordinated control strategy of both ends,power operating ranges of the three modulation methods are comprehensively analyzed and compared.Third,in order to solve power coupling at a low active power,the improved coordination control strategy at both ends in this paper is proposed and the relationships among active power,reactive power,DC current and phase angle difference are given in detail.Finally,a 500 kV/3 kA simulation system was built in PSCAD/EMTDC to obtain comparison results of the key operating characteristics of CSC under different modulation methods and the converter can realize unity power operation under random active power after adopting the improved coordinated control strategy,and DC current does not decrease to zero,verifying effectiveness of the coordinated control strategy.展开更多
Although fuel cells possess advantages of high energy conversion efficiency and zero-carbon emission,their large-scale commercialization is restricted by expensive and scarce platinum(Pt)catalysts.Metal-nitrogen-carbo...Although fuel cells possess advantages of high energy conversion efficiency and zero-carbon emission,their large-scale commercialization is restricted by expensive and scarce platinum(Pt)catalysts.Metal-nitrogen-carbon(M-Nx/C)catalysts are hailed as the most promising candidates to replace Pt due to their considerable oxygen reduction reaction(ORR)activity and low cost.Despite tremendous progress in terms of active site identification and activity improvement being achieved in the past few decades,the M-Nx/C catalysts still suffer from insufficient durability,which drastically limits their practical application.In this regard,understanding degradation mechanisms and customizing stabilization strategies are of significant importance yet challengeable.In this review,we summarize the recent advances in the stability improvement of M-Nx/C catalysts.The stability test protocols of the M-Nx/C are firstly introduced.Subsequently,with the combination of advanced ex situ and in situ characterization techniques and density functional theory calculation,we present a comprehensive overview of the main degradation mechanisms during ORR process.Aiming at these deactivation issues,a variety of novel improvement strategies are developed to enhance the stability of M-Nx/C.Finally,the current challenges and prospects to design highly stable M-Nx/C catalysts are also proposed.展开更多
With the rapid development of information technology in contemporary times,the blended teaching mode that blends online and offline courses has become an international trend in higher education.Taking blended tourism ...With the rapid development of information technology in contemporary times,the blended teaching mode that blends online and offline courses has become an international trend in higher education.Taking blended tourism management courses at Chongqing Three Gorges University as an example,we explored the impact of such teaching reform on student satisfaction based on the SERVPERF model.Empirical analysis of 179 valid questionnaires revealed that five elements of the reform,namely,reliability,assurance,valuableness,responsiveness,and empathy,have a significant positive impact on students’learning satisfaction.Specifically,in the context of blended courses,factors such as a stable and reliable teaching environment,comprehensively guaranteed educational conditions,teaching content that highly aligns with students’demands and value expectations,prompt responses to students’needs and feedback,and empathetic consideration of students’perspectives are critical for enhancing student satisfaction.Based on these conclusions,we propose several strategies and methods for improving the effectiveness of blended teaching in the hope of propelling its continuous improvement and optimization,thus further elevating the quality of higher education.展开更多
Double-metallic lead-free halide perovskites,Cs_(2)B^(I)B^(III)X_(6),sharing three-dimensional crystal structure,have been under the spotlight as the promising alternatives for the toxic and instable lead-based counte...Double-metallic lead-free halide perovskites,Cs_(2)B^(I)B^(III)X_(6),sharing three-dimensional crystal structure,have been under the spotlight as the promising alternatives for the toxic and instable lead-based counterparts.Interest in Cs_(2)B^(I)B^(III)X_(6)motivates intense research into their colloidal nanocrystals(NCs).Recently,Cs_(2)B^(I)B^(III)X_(6)NCs have made great progress in the optical performance via alloying or doping,but there are still great challenges for optoelectronic applications.In this review,the latest advances of Cs_(2)B^(I)B^(III)X_(6)NCs in synthesis approaches,bandgap engineering,photoluminescence(PL)optimization,and applications are summarized.The focus is put upon the composition-property relationships of Cs_(2)B^(I)B^(III)X_(6)NCs,which is approached by discussing the influences of composition variation on the electronic states,carrier dynamics,and optical properties.The challenges and the corresponding improving strategies in the development of high-effective and stable Cs_(2)B^(I)B^(III)X_(6)NCs for device applications are also highlighted.It is believed that this review can deepen the understanding on this burgeoning material system and shed light on their future research directions.展开更多
文摘At present,physical education is listed as the key teaching.This paper introduces the importance of physical education in Colleges and universities,analyzes the current situation of College Physical Education and explores the improvement strategies of College Physical Education at this stage.
基金2022 Education and Teaching Reform Research Project of Xi’an Medical University,“Construction and Practice of Teaching Quality Assurance System in Three-Level Teaching Bases of General Practice Medicine Under the‘Internet+’Model”(Project number:2022JG-05)2021 Shaanxi Undergraduate and Higher Continuing Education Teaching Reform Research Project of Shaanxi Provincial Department of Education,“Construction of Teaching Staff Based on‘Online Learning Platform for Clinical Teachers of the First Affiliated Hospital of Xi’an Medical University’and Construction and Practice of Quality Assurance System”(Project number:21BZ066)。
文摘The“New Medical Education”is a new requirement for the development of medical education in the new era.As a key and core element of the construction of the“New Medical Education,”the engagement in teaching work of university teachers is a key issue that determines the level of teaching development of university teachers and affects the quality of talent cultivation in universities.Using the literature review method,this study analyzed 39 relevant literatures retrieved from China National Knowledge Infrastructure(CNKI)from 1997 to 2023.The concept,connotation,current situation,influencing factors,and improvement strategies of teaching engagement by university teachers were reviewed and summarized.The results showed that the issue of teaching engagement by university teachers has not received high attention in the field of higher education,especially in higher medical education,which has not yet been reported.Although the overall number of literature is not large,some of the conclusions have important implications for the next research on the influencing factors and mechanisms of double-qualified teacher engagement in higher medical colleges.
基金Sponsored by the National Project of Scientific and Technical Supporting Programs Funded by Ministry of Science & Technology of China (Grant No.2013BAJ12B02)the National Natural Science Foundation of Heilongjiang (Grant No.E201316)the Fundamental Research Funds for the Central Universities (Grant No.HIT.KISTP.201419)
文摘To improve the comfortable physical environment for square in severe cold regions' rural areas. This paper applies the methods of questionnaires,field testing and statistical analysis to compare and analyze two different square cases of Qingyunpu in Liaoning Province,and conclude the main factors which affect the physical environmental comfort. The improvement strategies for physical environment of rural square are put forward from the aspects of site selection,road position,orientation,landscape design,and ground pavement material selection,aiming to provide the design basis for the physical environment of square in severe cold regions' rural areas.
基金Supported by National Natural Science Foundation of China(U1604110,U1404319,31270727,31600992)Key Project of Science and Technology in Henan Province(152102110100,152102110036)+5 种基金Nanhu Scholars Program for Young Scholars of XYNU(2016054)Major Science and Technology Project in Henan Province(121100110200)Science and Technology Innovation Team in Henan Province(14IRTSTHN012)Key Research Projects of Henan Higher Education Institutions(15A180059)Students Innovation and Training Program of XYNU(201710477032)Institute for Conservation and Utilization of Agrobioresources in Dabie Mountains(2016020)
文摘Enhancing the nutritional quality of food crops is a way to improve human nutrition and health. Grain protein content ( GPC ) is an important nutritional quality trait for rice and many other crops. Therefore, it will be very significant to increase GPC and improve rice quality. This paper mainly reviewed the genetic studies GPC in rice, mapping and cloning of QTLs and genes associated with GPC. However, little is known about the molecular mechanism and gene function related to GPC in rice. Thus, here we put forward the genetic strategy by gene pyramiding or molecular marker assisted selection to improve GPC and nutritional quality in rice. This review could provide important information for genetic improvement of grain nutritional quality of rice.
文摘This article discusses the various blood interactions that may occur with various types of nano drug-loading systems. Nanoparticles enter the blood circulation as foreign objects. On the one hand, they may cause a series of inflammatory reactions and immune reactions, resulting in the rapid elimination of immune cells and the reticuloendothelial system, affecting their durability in the blood circulation. On the other hand, the premise of the drug-carrying system to play a therapeutic role depends on whether they cause coagulation and platelet activation, the absence of hemolysis and the elimination of immune cells. For different forms of nano drug-carrying systems, we can find the characteristics, elements and coping strategies of adverse blood reactions that we can find in previous researches. These adverse reactions may include destruction of blood cells, abnormal coagulation system, abnormal effects of plasma proteins, abnormal blood cell behavior, adverse immune and inflammatory reactions, and excessive vascular stimulation. In order to provide help for future research and formulation work on the blood compatibility of nano drug carriers.
文摘English online learning has been common trend in the world, how to teach and learn effectively in EFL classes through online environment is an urgent study. The purpose of the study to analyze the factors of affecting the effectiveness of online teaching and learning in EFL classes in college. We build up a three-dimensional model in the perspective of teacher, learner and technology. And we propose the strategies of improving the effectiveness of online teaching and learning in EFL classes in college in the dimensions of teacher, learner and technology.
基金supported by Fondation pour la Recherche Médicale(Equipe FRM),SATT Sud Est-Accelerator of Technology Transfer,Association France Parkinson,Fondation de France(Committee Parkinson),COST Action CM1106
文摘Recent advances in stem cell technologies have opened new avenues for the treatment of a number of diseases still lacking effective therapeutic options.Cell transplantation has emerged as among the most promising clinical intervention for disorders such as injuries,diabetes,liver diseases, neurodegeneration and heart failure (Lee et al., 2013; Forbes and Rosenthal, 2014; Tabar and Studer, 2014).
文摘The development course of China's meteorological movie and television was analyzed firstly, and then the improvement strategies of meteorological movie and television services facing public needs were put forward based on the statistical results of a meteorological service questionnaire.
文摘With the consistent development of society,economy and culture,people have had increasing requirements on high-quality public spaces.However,current landscapes have been far away from equal and just for various causes,and to explore the realization of landscape justice has become a key concern in the fi eld of landscape architecture.Greenway as a linear space with bigger scale and strong connectivity in the current green space inventory is easier to update,so it provides a new direction for realizing landscape justice.This paper analyzed the existing greenway policies,design and planning,and problems in using,provided corresponding strategies for improvement,so as to achieve the landscape justice,provide new ideas and instructions for the present greenway construction and maintenance.
基金The Introduce Talent Foundation of Wenzhou University(135010120719).
文摘Research self-efficacy is of great significance for teachers to improve their interest and achievements in scientific research.In this study,261 elementary teachers were surveyed through online questionnaires to understand their research self-efficacy.The results showed that most elementary teachers have good research self-efficacy;education background,years of teaching,research environment,and attitude toward research all had influence on the research self-efficacy of elementary teachers.Based on this situation,schools should make efforts,such as improving communication,providing financial support,establishing a scientific research support center,and helping teachers under unfavorable situations.For elementary teachers,they should realize the importance of education research and improve their research literacy。
文摘Objective To investigate influence of immunosuppression strategy optimization on outcomes of renal transplant recipients in the last decades. Methods Data from 404 renal transplant recipients from Jan. 1st,2001 to Dec. 31st,2010 were analyzed retrospectively. The pa-
基金the Shenyang University of Technology(QNPY202209-4)the Key R&D project of Liaoning Province of China(2020JH2/10300079)+2 种基金the“Liaoning BaiQianWan Talents Program”(2018921006)the Liaoning Revitalization Talents Program(XLYC1908034)the National Natural Science Foundation of China(21571132).
文摘Potassium-ion batteries(PIBs)have been considered as promising candidates in the post-lithium-ion battery era.Till now,a large number of materials have been used as electrode materials for PIBs,among which vanadium oxides exhibit great potentiality.Vanadium oxides can provide multiple electron transfers during electrochemical reactions because vanadium possesses a variety of oxidation states.Meanwhile,their relatively low cost and superior material,structural,and physicochemical properties endow them with strong competitiveness.Although some inspiring research results have been achieved,many issues and challenges remain to be further addressed.Herein,we systematically summarize the research progress of vanadium oxides for PIBs.Then,feasible improvement strategies for the material properties and electrochemical performance are introduced.Finally,the existing challenges and perspectives are discussed with a view to promoting the development of vanadium oxides and accelerating their practical applications.
基金supported in part by the National Natural Science Foundation of China (62033009)the Creative Activity Plan for Science and Technology Commission of Shanghai (20510712300,21DZ2293500)the Supported by Science Foundation of Donghai Laboratory。
文摘In this paper, the fixed-time event-triggered obstacle avoidance consensus control for a multi-AUV time-varying formation system in a 3D environment is presented by using an improved artificial potential field and leader-follower strategy(IAPF-LF). Firstly, the proposed fixed-time control can achieve the desired multi-AUV formation within a fixed settling time in any initial system state. Secondly, an event-triggered communication strategy is developed to govern the communication among AUVs, and the communication energy consumption can be decremented. The time-varying formation obstacle avoidance control algorithm based on IAPF-LF is designed to avoid static and dynamic obstacles, the desired formation is maintained in the presence of external disturbances, and there is no Zeno behavior under the fixed-time event-triggered consensus control strategy.The stability of the system is proved by the Lyapunov function and inequality scaling. Finally, simulation examples and water pool experiments are reported to verify the performance of the proposed theoretical algorithms.
基金United Arab Emirates University (UAE) for providing funding of this research undergrant # 12N097。
文摘Using sunlight to drive chemical reactions via photocatalysis is paramount for a sustainable future.Among several photocatalysts,employing layered double hydrides(LDH) for photocatalytic application is most straightforward and desirable owing to their distinctive two-dimensional(2D) lamellar structure and optical attributes.This article reviews the advancements in bimetallic/trimetallic LDHs and various strategies to achieve high efficiency toward an outstanding performing photocatalyst.Firstly,the tuning of LDH components that control the electro nic and structural properties is explained.The tu ning obtained through the adoption,combination,and incorporation of different cations and anions is also explained.The progress of modification methods,such as the adoption of different morphologies,delamination,and defect engineering towards enhanced photocatalytic activities,is discussed in the mainstream.The band engineering,structural characteristics,and redox tuning are further deliberated to maximize solar energy harvesting for different photocatalytic applications.Finally,the progress obtained in forming hierarchical heterostructures through hybridization with other semiconductors or conducting materials is systematically disclosed to get maximum photocatalytic performance.Moreover,the structural changes during the in-situ synthesis of LDH and the stability of LDH-based photocatalysts are deliberated.The review also summarizes the improvements in LDH properties obtained through modification tactics and discusses the prospects for future energy and environmental applications.
文摘 There are two categories of tropical crop machinery. One comprises operation machinery that is used for planting, managing and harvesting tropical crops, while the other comprises process machinery for processing tropical crops. Tropical crop machinery is distinguished from other agricultural machinery by the special crops that such machinery cultivates and processes.……
基金supported in part by Science and Technology Project of State Grid Corporation of China.(5500202058059A0000).
文摘Because of its controlled power factor and no commutation failure,current source converter(CSC)made up of reverse-blocking IGCTs(RB-IGCTs)offers broad application prospects in the field of HVDC system.Valve voltage and power operating range as the most important operating characteristics should be paid attention to but they are always contradictory.First,the relationship between valve voltage and modulation index is obtained.In particular,valve voltage of converter under the three typical modulation methods is compared,analyzed,and verified.Second,with the help of the independent control strategy and coordinated control strategy of both ends,power operating ranges of the three modulation methods are comprehensively analyzed and compared.Third,in order to solve power coupling at a low active power,the improved coordination control strategy at both ends in this paper is proposed and the relationships among active power,reactive power,DC current and phase angle difference are given in detail.Finally,a 500 kV/3 kA simulation system was built in PSCAD/EMTDC to obtain comparison results of the key operating characteristics of CSC under different modulation methods and the converter can realize unity power operation under random active power after adopting the improved coordinated control strategy,and DC current does not decrease to zero,verifying effectiveness of the coordinated control strategy.
基金supported by the National Key R&D Program of China(grant no.2022YFB4004100)National Natural Science Foundation of China(grant nos.22272161 and 22179126)Jilin Province Science and Technology Development Program(grant no.20230101367JC).
文摘Although fuel cells possess advantages of high energy conversion efficiency and zero-carbon emission,their large-scale commercialization is restricted by expensive and scarce platinum(Pt)catalysts.Metal-nitrogen-carbon(M-Nx/C)catalysts are hailed as the most promising candidates to replace Pt due to their considerable oxygen reduction reaction(ORR)activity and low cost.Despite tremendous progress in terms of active site identification and activity improvement being achieved in the past few decades,the M-Nx/C catalysts still suffer from insufficient durability,which drastically limits their practical application.In this regard,understanding degradation mechanisms and customizing stabilization strategies are of significant importance yet challengeable.In this review,we summarize the recent advances in the stability improvement of M-Nx/C catalysts.The stability test protocols of the M-Nx/C are firstly introduced.Subsequently,with the combination of advanced ex situ and in situ characterization techniques and density functional theory calculation,we present a comprehensive overview of the main degradation mechanisms during ORR process.Aiming at these deactivation issues,a variety of novel improvement strategies are developed to enhance the stability of M-Nx/C.Finally,the current challenges and prospects to design highly stable M-Nx/C catalysts are also proposed.
基金funded by the 2021 Chongqing Three Gorges University Higher Education Reform Project“Research on the Improvement of Teaching Quality in Blended Courses for Tourism Management”(JGZC2146)the Science and Technology Research Plan Project of Chongqing Municipal Education Commission“Research on the Effectiveness and Intrinsic Mechanisms of Virtual Spokespersons in Tourism Marketing in the Context of Digital Economy”(KJQN202301240)the Project of Chengdu-Chongqing Research Center for Coordinated Development of Education and Economic Society“Research on the Implementation Effect of the‘Double Reduction’Policy in Ethnic Regions in Sichuan and Chongqing:Based on the Parents’Perspective”(CYJXF23022).
文摘With the rapid development of information technology in contemporary times,the blended teaching mode that blends online and offline courses has become an international trend in higher education.Taking blended tourism management courses at Chongqing Three Gorges University as an example,we explored the impact of such teaching reform on student satisfaction based on the SERVPERF model.Empirical analysis of 179 valid questionnaires revealed that five elements of the reform,namely,reliability,assurance,valuableness,responsiveness,and empathy,have a significant positive impact on students’learning satisfaction.Specifically,in the context of blended courses,factors such as a stable and reliable teaching environment,comprehensively guaranteed educational conditions,teaching content that highly aligns with students’demands and value expectations,prompt responses to students’needs and feedback,and empathetic consideration of students’perspectives are critical for enhancing student satisfaction.Based on these conclusions,we propose several strategies and methods for improving the effectiveness of blended teaching in the hope of propelling its continuous improvement and optimization,thus further elevating the quality of higher education.
基金supported by the Natural Science Foundation of Fujian Province(No.2021J01315)Quanzhou Scientific Research Project(No.2021GZ4).
文摘Double-metallic lead-free halide perovskites,Cs_(2)B^(I)B^(III)X_(6),sharing three-dimensional crystal structure,have been under the spotlight as the promising alternatives for the toxic and instable lead-based counterparts.Interest in Cs_(2)B^(I)B^(III)X_(6)motivates intense research into their colloidal nanocrystals(NCs).Recently,Cs_(2)B^(I)B^(III)X_(6)NCs have made great progress in the optical performance via alloying or doping,but there are still great challenges for optoelectronic applications.In this review,the latest advances of Cs_(2)B^(I)B^(III)X_(6)NCs in synthesis approaches,bandgap engineering,photoluminescence(PL)optimization,and applications are summarized.The focus is put upon the composition-property relationships of Cs_(2)B^(I)B^(III)X_(6)NCs,which is approached by discussing the influences of composition variation on the electronic states,carrier dynamics,and optical properties.The challenges and the corresponding improving strategies in the development of high-effective and stable Cs_(2)B^(I)B^(III)X_(6)NCs for device applications are also highlighted.It is believed that this review can deepen the understanding on this burgeoning material system and shed light on their future research directions.