Carbon materials are a key component in energy storage and conversion devices and their microstructure plays a crucial role in determining device performance.However,traditional carbon materials are unable to meet the...Carbon materials are a key component in energy storage and conversion devices and their microstructure plays a crucial role in determining device performance.However,traditional carbon materials are unable to meet the requirements for applications in emerging fields such as renewable energy and electric vehicles due to limitations including a disordered structure and uncontrolled defects.With an aim of realizing devisable structures,adjustable functions,and performance breakthroughs,superstructured carbons is proposed and represent a category of carbon-based materials,characterized by precisely-built pores,networks,and interfaces.Superstructured carbons can overcome the limitations of traditional carbon materials and improve the performance of energy storage and conversion devices.We review the structure-activity relationships of superstructured carbons and recent research advances from three aspects including a precisely customized pore structure,a dense carbon network framework,and a multi-component highly coupled interface between the different components.Finally,we provide an outlook on the future development of and practical challenges in energy storage and conversion devices.展开更多
The research achievements of solidification theories and technologies in the last decades are reviewed with the stresses on some new development in the recent years. Some new interesting areas emerged in the last year...The research achievements of solidification theories and technologies in the last decades are reviewed with the stresses on some new development in the recent years. Some new interesting areas emerged in the last years are also pointed out.展开更多
The development of tissue-engineered technology brings hope to the treatment of spinal cord injury. Preparation of a tissue-engineered spinal cord stent with three-dimensional bionic structure has important value in t...The development of tissue-engineered technology brings hope to the treatment of spinal cord injury. Preparation of a tissue-engineered spinal cord stent with three-dimensional bionic structure has important value in the construction of tissue-engineered spinal cord and the repair of spinal cord injury. Acellular scaffolds can be produced with chemical extraction,展开更多
The rising cost and limited availability of fossil fuels, and the increasing concerns related to their role on global pollution and greenhouse effect have pushed considerably the need to accelerate the transition to a...The rising cost and limited availability of fossil fuels, and the increasing concerns related to their role on global pollution and greenhouse effect have pushed considerably the need to accelerate the transition to a more sustainable use of energy based largely on renewable energy sources. Nanocarbon materials play a critical role in this transition, as they are the key materials for components of different devices necessary in enabling this transition （batteries, fuel cells, solar cells, etc.）. This issue collects 22 contributions, including one perspective and six review papers on the topic of carbon materials for energy applications, written by well-known experts in this field. It is really an exciting special issue that gives a very updated view of this topic, as well as trends and outlooks in this breakthrough research area. The initial perspective paper introduces the different possibilities offered from the growing level of knowledge in this area, testified from the exponentially rising number of publications. It also discusses the basie concepts for a rational design of these nanomaterials. The lk）llowing six reviews address different specific aspects of synthesis, characterization and use of carbon nanomaterials, from fuel cells to composite electrodes, supercapacitors and photoelectrochemical devices for CO2 conversion. These reviews represent an unique opportunity for the readers to be updated on the latest developments of new carbon families such as fullerene, grapbene, and carbon nanotube, and their derived nanocarbon materials （from carbon quantum dots to nanohorn, nanofiber, nano ribbon, etc.）. Second generation nanocarbons, including modification of these nanocarbons by surface functionalization or doping with heteroatoms to create specific tailored properties, and nanoarchitectured supramolecular hybrids, are also discussed. Finally, 1 communication and 14 full articles discuss several aspects of the use of these nanocarbon materials to develop new catalysts for a range of applications （from biomass conversion to Fisher-Tropsch reaction and electrochemical devices） and new materials for energy storage and conversion （adsorption pumps, Li-ion and Li-S batteries, electrodes for electrochemical uses）. We thus believe that this special issue dedicated to the use and development of carbon materials for energy applications represents a unique occasion for young and experienced researchers as well as for managers in the field of sustainable energy to have an updated view on this enabling topic for the future of our society. We thus invite all to have this special issue as a privileged component of your bookshelf.展开更多
Due to the outbreak of |x-19,colleges and universities have actively responded to the call of the state to carry out online teaching in completing their teaching tasks.After the epidemic,the online and offline hybrid ...Due to the outbreak of |x-19,colleges and universities have actively responded to the call of the state to carry out online teaching in completing their teaching tasks.After the epidemic,the online and offline hybrid teaching has become a novel mode of teaching which meets the requirements of teaching reform and the information society.This teaching method integrates both the online and offline teaching which plays an important role in enhancing teaching qualities and learning experiences.However,due to the lack of experience,there are some issues occurring in the teaching process of this method.The Luminescent Materials and Applications course is used as the subject in this article.The difficulties in traditional offline teaching as well as the advantages,detailed course construction process,and effectiveness evaluation of hybrid teaching are summarized and meticulously analyzed.In regard to that,the application of the online and offline hybrid teaching in the Luminescent Materials and Applications course is beneficial to the learning of professional knowledge and the cultivation of students'scientific literacy.Therefore,it is an effective way to improve and enrich this course by using the online and offline hybrid teaching method.展开更多
Electrospinning technology has emerged as a promising method for fabricating flexible lithium-ion batter-ies(FLIBs)due to its ability to create materials with desir-able properties for energy storage applications.FLIB...Electrospinning technology has emerged as a promising method for fabricating flexible lithium-ion batter-ies(FLIBs)due to its ability to create materials with desir-able properties for energy storage applications.FLIBs,which are foldable and have high energy densities,are be-coming increasingly important as power sources for wear-able devices,flexible electronics,and mobile energy applica-tions.Carbon materials,especially carbon nanofibers,are pivotal in improving the performance of FLIBs by increas-ing electrical conductivity,chemical stability,and surface area,as well as reducing costs.These materials also play a significant role in establishing conducting networks and im-proving structural integrity,which are essential for extend-ing the cycle life and enhancing the safety of the batteries.This review considers the role of electrospinning in the fabrication of critical FLIB components,with a particular emphasis on the integration of carbon materials.It explores strategies to optimize FLIB performance by fine-tuning the electrospinning para-meters,such as electric field strength,spinning rate,solution concentration,and carbonization process.Precise control over fiber properties is crucial for enhancing battery reliability and stability during folding and bending.It also highlights the latest research findings in carbon-based electrode materials,high-performance electrolytes,and separator structures,discussing the practical challenges and opportunities these materials present.It underscores the significant impact of carbon materials on the evolution of FLIBs and their potential to shape future energy storage technologies.展开更多
Anion exchange membrane(AEM),as a kind of key membrane materials,has shown great application potential in many electrochemical fields,and remarkable progress has been made in related research in recent years.In this p...Anion exchange membrane(AEM),as a kind of key membrane materials,has shown great application potential in many electrochemical fields,and remarkable progress has been made in related research in recent years.In this paper,the research status of AEM is reviewed,including its material design,preparation method,performance optimization and application in the fields of hydrogen production by electrolytic water,fuel cell and water treatment.In terms of material design,new polymer skeleton structures are emerging to regulate the stability of ion conduction channels and membranes by introducing specific functional groups or changing the molecular chain structure.The preparation methods have been gradually expanded from the traditional solution casting method to more advanced technologies,such as interfacial polymerization and electrostatic spinning,which effectively improve the microstructure and property uniformity of the film.Performance optimization focuses on improving ion conductivity,reducing membrane swelling rate and enhancing chemical stability,and a variety of modification strategies are developed and applied.Despite the achievements made so far,there are still some challenges,such as the lack of long-term stability in highly alkaline environments.Future research needs to further explore new material systems and preparation processes in order to promote the wide application and sustainable development of AEM technology in energy,environmental protection and other fields.展开更多
Aesthetics,referred frequently to as a philosophical term,has played a starring role in forming and evolving a number of aspects of human society,including arts,politics,economics,ethics,etc.Indeed,exploring and inves...Aesthetics,referred frequently to as a philosophical term,has played a starring role in forming and evolving a number of aspects of human society,including arts,politics,economics,ethics,etc.Indeed,exploring and investigating the aesthetic phenomena in the scientific field have aroused insightful research findings,which in turn has stimulated research interests in such a science-aesthetics field.In particular,better-evaluated aesthetic aspects of the materials field are expected to be uncovered upon the exceedingly-exposed fundamental breakthroughs in researching the basic structure and functionality of materials.In this report,we glimpse into the aesthetic simplicity of energy materials and comprehend specifically the mass transfer functionalities of key categories of energy materials through an intuitive and bottom-up approach.Our effort aspires to shed new lights on the functionality understanding and manipulation of functional materials in general.展开更多
The nonlinear optical （NLO） and optical limiting （OL） properties of three new structures of organic NLO vip host Poly（N-vinylcarbozole）/disperse orange 3 （PVK/DO3）, PVK/disperse orange 13 （PVK/DO13）. and P...The nonlinear optical （NLO） and optical limiting （OL） properties of three new structures of organic NLO vip host Poly（N-vinylcarbozole）/disperse orange 3 （PVK/DO3）, PVK/disperse orange 13 （PVK/DO13）. and PVK/disperse orange 25 （PVK/DO25） as a solution at different concentrations and as a thin-film sample are studied using continuous wave z-scan system at 532 nm. The open-aperture z-scan data of the NLO materials in the solution and thin-film samples displayed two-photon and saturable absorptions, respectively. The PVK/DO13 exhibites the largest and best values of the nonlinearities, such as n2, β, X（3） compared with those of PVK/DO3 and PVK/DO25. This nonlinearity increases as the concentration increases. Tile results indicate that these NLO materials are good candidates for optical switching and OL devices.展开更多
In classical Chinese gardens,the waterscape has its own unique style of expression,which is to highlight the simulation of the natural water landscape and its combination with the elements of the garden.As a pole of c...In classical Chinese gardens,the waterscape has its own unique style of expression,which is to highlight the simulation of the natural water landscape and its combination with the elements of the garden.As a pole of classical garden theory,waterscape plays an important role in organizing space and creating the overall landscape effect.In addition to the landscape concept and water management method,the combination of engineering practices and landscape aesthetics involved guarantees Artistic presentation of water bodies in gardens.Based on the existing research,this study cut in from the perspective of engineering technology,and conducted detailed research on engineering techniques,materials application and artistic expression under different water body functions and forms,and explored the fusion of "making" "technique" and "art" in the waterscape construction.展开更多
Electronic systems that can cover large areas on flexible/stretchable substrateshave received increasing attention in the past several years because they enable new classes of applications that lie outside those easil...Electronic systems that can cover large areas on flexible/stretchable substrateshave received increasing attention in the past several years because they enable new classes of applications that lie outside those easily addressed with wafer-based microelectronics.Some attractive examples include flexible displays,flexible solar cells,electronic textiles,sensory skins,detectors,active antennas,etc.The field expends very fast and great developments have been obtained展开更多
The mechanic affection on the blast holewalls is simply analyzed and cracking propaga-tion caused by shaped charge is explained inthis paper. In the rock materials cutting, pri-
Energy harvesting is an appealing technology that makes use of the ambient energy which is otherwise wasted. Piezoelectric materials directly convert the elastic energy to the electric energy, and thus have a great ad...Energy harvesting is an appealing technology that makes use of the ambient energy which is otherwise wasted. Piezoelectric materials directly convert the elastic energy to the electric energy, and thus have a great advantage in scavenging vibrational energy for simplicity in device structure with relatively high power density. This paper provides an overview on the research of piezoelectric materials in energy harvesting in recent decades, from basics of piezoelectricity and working principle of energy harvesting with piezoelectric materials, to the progress of development of high-performance piezoelectrics including ceramics, single crystals and polymers, then to experimental attempts on the device fabrication and optimization, finally to perspective applications of piezoelectric energy harvesting(PEH). The criteria for selection of materials for PEH applications are introduced. Not only the figure of merit but also maximum allowable stress of materials are taken into account in the evaluation of their potential in achieving high energy density and output power density. The influence of the device configuration on the performance is also acknowledged and discussed. The magnitude and distribution of induced stress in the piezoelectric unit upon excitation by the vibration source play an important role in determining the output power density and can be tuned via proper design of device configuration without changing its resonant frequency. Approaches to address the issue of frequency match accompanying with the resonant mode are illustrated with literature examples. Usage of PEH devices can be extended to a variety of vibration sources in everyday life as well as in nature. Some appealing applications of PEH, such as in implantable and wearable devices, are reviewed.展开更多
The fact that InN has a direct bandgap of 0.75eV enables InN-based nitrides devices to cover the wavelength range from UV region to 1.8μm, therefore, emerging as a new material system for optical communication applic...The fact that InN has a direct bandgap of 0.75eV enables InN-based nitrides devices to cover the wavelength range from UV region to 1.8μm, therefore, emerging as a new material system for optical communication applications.展开更多
A long-term field experiment on organic material application and crop rotation with green manure crops has been conducted since 1976 at Lopburi Agricultural Research and Development Center,Department of Agriculture,Lo...A long-term field experiment on organic material application and crop rotation with green manure crops has been conducted since 1976 at Lopburi Agricultural Research and Development Center,Department of Agriculture,Lop Buri Province,Thailand,to clarify the effect of organic materials and green manure crop on soil organic carbon changes.The stock change factors that stand for the relative change of soil organic carbon on the carbon stock in a reference condition(native vegetation that is not degraded or improved).Stock change factor for input of organic matter(F1),representing different levels of C input to soil such as organic material application,crop residue treatment and green manure crop cultivation,was computed with the present field experimental results.While the computed F1 of"High input with manure"was within the range of IPCC default F1 value,some of the computed F1 of"High input without manure"was much higher than the IPCC default though it was varied due to the biomass production and nutrient contents of the green manure crops planted as the second crops after corn.Therefore,the F1 computed by field experimental results can contribute to more accurate estimation of SOC changes in farm land especially in Southeast Asia because the default F1 mostly depends on the experimental data in temperate zones.Moreover,the field experiment has focused the effect of reduced tillage practices on SOC changes and corn yield since 2011.The results of the experiment will be used to compute Stock change factor for management regime(FMC)which represents the effects of tillage operations.展开更多
Two-dimensional（2D） materials have recently received a great deal of attention due to their unique structures and fascinating properties,as well as their potential applications.2D hexagonal boron nitride（2D hBN）,a...Two-dimensional（2D） materials have recently received a great deal of attention due to their unique structures and fascinating properties,as well as their potential applications.2D hexagonal boron nitride（2D hBN）,an insulator with excellent thermal stability,chemical inertness,and unique electronic and optical properties,and a band gap of 5.97 e V,is considered to be an ideal candidate for integration with other 2D materials.Nevertheless,the controllable growth of high-quality 2D h-BN is still a great challenge.A comprehensive overview of the progress that has been made in the synthesis of 2D h-BN is presented,highlighting the advantages and disadvantages of various synthesis approaches.In addition,the electronic,optical,thermal,and mechanical properties,heterostructures,and related applications of 2D h-BN are discussed.展开更多
文摘Carbon materials are a key component in energy storage and conversion devices and their microstructure plays a crucial role in determining device performance.However,traditional carbon materials are unable to meet the requirements for applications in emerging fields such as renewable energy and electric vehicles due to limitations including a disordered structure and uncontrolled defects.With an aim of realizing devisable structures,adjustable functions,and performance breakthroughs,superstructured carbons is proposed and represent a category of carbon-based materials,characterized by precisely-built pores,networks,and interfaces.Superstructured carbons can overcome the limitations of traditional carbon materials and improve the performance of energy storage and conversion devices.We review the structure-activity relationships of superstructured carbons and recent research advances from three aspects including a precisely customized pore structure,a dense carbon network framework,and a multi-component highly coupled interface between the different components.Finally,we provide an outlook on the future development of and practical challenges in energy storage and conversion devices.
文摘The research achievements of solidification theories and technologies in the last decades are reviewed with the stresses on some new development in the recent years. Some new interesting areas emerged in the last years are also pointed out.
文摘The development of tissue-engineered technology brings hope to the treatment of spinal cord injury. Preparation of a tissue-engineered spinal cord stent with three-dimensional bionic structure has important value in the construction of tissue-engineered spinal cord and the repair of spinal cord injury. Acellular scaffolds can be produced with chemical extraction,
文摘The rising cost and limited availability of fossil fuels, and the increasing concerns related to their role on global pollution and greenhouse effect have pushed considerably the need to accelerate the transition to a more sustainable use of energy based largely on renewable energy sources. Nanocarbon materials play a critical role in this transition, as they are the key materials for components of different devices necessary in enabling this transition （batteries, fuel cells, solar cells, etc.）. This issue collects 22 contributions, including one perspective and six review papers on the topic of carbon materials for energy applications, written by well-known experts in this field. It is really an exciting special issue that gives a very updated view of this topic, as well as trends and outlooks in this breakthrough research area. The initial perspective paper introduces the different possibilities offered from the growing level of knowledge in this area, testified from the exponentially rising number of publications. It also discusses the basie concepts for a rational design of these nanomaterials. The lk）llowing six reviews address different specific aspects of synthesis, characterization and use of carbon nanomaterials, from fuel cells to composite electrodes, supercapacitors and photoelectrochemical devices for CO2 conversion. These reviews represent an unique opportunity for the readers to be updated on the latest developments of new carbon families such as fullerene, grapbene, and carbon nanotube, and their derived nanocarbon materials （from carbon quantum dots to nanohorn, nanofiber, nano ribbon, etc.）. Second generation nanocarbons, including modification of these nanocarbons by surface functionalization or doping with heteroatoms to create specific tailored properties, and nanoarchitectured supramolecular hybrids, are also discussed. Finally, 1 communication and 14 full articles discuss several aspects of the use of these nanocarbon materials to develop new catalysts for a range of applications （from biomass conversion to Fisher-Tropsch reaction and electrochemical devices） and new materials for energy storage and conversion （adsorption pumps, Li-ion and Li-S batteries, electrodes for electrochemical uses）. We thus believe that this special issue dedicated to the use and development of carbon materials for energy applications represents a unique occasion for young and experienced researchers as well as for managers in the field of sustainable energy to have an updated view on this enabling topic for the future of our society. We thus invite all to have this special issue as a privileged component of your bookshelf.
基金supported by the 2019-2021 Undergraduate Teaching Project of Chengdu University of Information Technology(BKJX2020022,BKJX2020081)Department of Human Resources and Social Security of Sichuan Province(2019Z226).
文摘Due to the outbreak of |x-19,colleges and universities have actively responded to the call of the state to carry out online teaching in completing their teaching tasks.After the epidemic,the online and offline hybrid teaching has become a novel mode of teaching which meets the requirements of teaching reform and the information society.This teaching method integrates both the online and offline teaching which plays an important role in enhancing teaching qualities and learning experiences.However,due to the lack of experience,there are some issues occurring in the teaching process of this method.The Luminescent Materials and Applications course is used as the subject in this article.The difficulties in traditional offline teaching as well as the advantages,detailed course construction process,and effectiveness evaluation of hybrid teaching are summarized and meticulously analyzed.In regard to that,the application of the online and offline hybrid teaching in the Luminescent Materials and Applications course is beneficial to the learning of professional knowledge and the cultivation of students'scientific literacy.Therefore,it is an effective way to improve and enrich this course by using the online and offline hybrid teaching method.
文摘Electrospinning technology has emerged as a promising method for fabricating flexible lithium-ion batter-ies(FLIBs)due to its ability to create materials with desir-able properties for energy storage applications.FLIBs,which are foldable and have high energy densities,are be-coming increasingly important as power sources for wear-able devices,flexible electronics,and mobile energy applica-tions.Carbon materials,especially carbon nanofibers,are pivotal in improving the performance of FLIBs by increas-ing electrical conductivity,chemical stability,and surface area,as well as reducing costs.These materials also play a significant role in establishing conducting networks and im-proving structural integrity,which are essential for extend-ing the cycle life and enhancing the safety of the batteries.This review considers the role of electrospinning in the fabrication of critical FLIB components,with a particular emphasis on the integration of carbon materials.It explores strategies to optimize FLIB performance by fine-tuning the electrospinning para-meters,such as electric field strength,spinning rate,solution concentration,and carbonization process.Precise control over fiber properties is crucial for enhancing battery reliability and stability during folding and bending.It also highlights the latest research findings in carbon-based electrode materials,high-performance electrolytes,and separator structures,discussing the practical challenges and opportunities these materials present.It underscores the significant impact of carbon materials on the evolution of FLIBs and their potential to shape future energy storage technologies.
基金“Grassland Talents”of Inner Mongolia Autonomous Region,Young Talents of Science and Technology in Universities of Inner Mongolia Autonomous Region(NJYT23030)Technology Breakthrough Engineering Hydrogen Energy Field“Unveiling and Leading”Project(2024KJTW0018)+3 种基金“Steed Plan High Level Talents”of Inner Mongolia University,Carbon neutralization research project(STZX202218)National Natural Science Foundation of China(U22A20107),Inner Mongolia Autonomous Region Natural Science Foundation(2023MS02002)Guangdong Provincial Key Laboratory of Materials and Technologies for Energy Conversion(MATEC2024KF011)National Key R&D Program of China(2022YFA1205201).
文摘Anion exchange membrane(AEM),as a kind of key membrane materials,has shown great application potential in many electrochemical fields,and remarkable progress has been made in related research in recent years.In this paper,the research status of AEM is reviewed,including its material design,preparation method,performance optimization and application in the fields of hydrogen production by electrolytic water,fuel cell and water treatment.In terms of material design,new polymer skeleton structures are emerging to regulate the stability of ion conduction channels and membranes by introducing specific functional groups or changing the molecular chain structure.The preparation methods have been gradually expanded from the traditional solution casting method to more advanced technologies,such as interfacial polymerization and electrostatic spinning,which effectively improve the microstructure and property uniformity of the film.Performance optimization focuses on improving ion conductivity,reducing membrane swelling rate and enhancing chemical stability,and a variety of modification strategies are developed and applied.Despite the achievements made so far,there are still some challenges,such as the lack of long-term stability in highly alkaline environments.Future research needs to further explore new material systems and preparation processes in order to promote the wide application and sustainable development of AEM technology in energy,environmental protection and other fields.
基金supported by the National Natural Science Foundation under Gran No.21403031Fundamental Research Funds for the Chinese Centra Universities under Grant No.ZYGX2014J088 and No.ZYGX2015Z003
文摘Aesthetics,referred frequently to as a philosophical term,has played a starring role in forming and evolving a number of aspects of human society,including arts,politics,economics,ethics,etc.Indeed,exploring and investigating the aesthetic phenomena in the scientific field have aroused insightful research findings,which in turn has stimulated research interests in such a science-aesthetics field.In particular,better-evaluated aesthetic aspects of the materials field are expected to be uncovered upon the exceedingly-exposed fundamental breakthroughs in researching the basic structure and functionality of materials.In this report,we glimpse into the aesthetic simplicity of energy materials and comprehend specifically the mass transfer functionalities of key categories of energy materials through an intuitive and bottom-up approach.Our effort aspires to shed new lights on the functionality understanding and manipulation of functional materials in general.
文摘The nonlinear optical （NLO） and optical limiting （OL） properties of three new structures of organic NLO vip host Poly（N-vinylcarbozole）/disperse orange 3 （PVK/DO3）, PVK/disperse orange 13 （PVK/DO13）. and PVK/disperse orange 25 （PVK/DO25） as a solution at different concentrations and as a thin-film sample are studied using continuous wave z-scan system at 532 nm. The open-aperture z-scan data of the NLO materials in the solution and thin-film samples displayed two-photon and saturable absorptions, respectively. The PVK/DO13 exhibites the largest and best values of the nonlinearities, such as n2, β, X（3） compared with those of PVK/DO3 and PVK/DO25. This nonlinearity increases as the concentration increases. Tile results indicate that these NLO materials are good candidates for optical switching and OL devices.
基金Youth Fund Project of the National Natural Science Foundation of China(51808005)General Social Science Project of Beijing Municipal Education Commission(SM201910009008)Youth Yuyou Talent Training Plan of North China University of Technology(NCUT2020).
文摘In classical Chinese gardens,the waterscape has its own unique style of expression,which is to highlight the simulation of the natural water landscape and its combination with the elements of the garden.As a pole of classical garden theory,waterscape plays an important role in organizing space and creating the overall landscape effect.In addition to the landscape concept and water management method,the combination of engineering practices and landscape aesthetics involved guarantees Artistic presentation of water bodies in gardens.Based on the existing research,this study cut in from the perspective of engineering technology,and conducted detailed research on engineering techniques,materials application and artistic expression under different water body functions and forms,and explored the fusion of "making" "technique" and "art" in the waterscape construction.
文摘Electronic systems that can cover large areas on flexible/stretchable substrateshave received increasing attention in the past several years because they enable new classes of applications that lie outside those easily addressed with wafer-based microelectronics.Some attractive examples include flexible displays,flexible solar cells,electronic textiles,sensory skins,detectors,active antennas,etc.The field expends very fast and great developments have been obtained
文摘The mechanic affection on the blast holewalls is simply analyzed and cracking propaga-tion caused by shaped charge is explained inthis paper. In the rock materials cutting, pri-
基金supported by the National Natural Science Foundation of China(Grant No.51302143)Shenzhen Special Fund for the Development of Emerging Industries(Grant No.JCYJ20140417115840233)Shenzhen Peacock Plan(Grant No.KQCX20140521161756228)
文摘Energy harvesting is an appealing technology that makes use of the ambient energy which is otherwise wasted. Piezoelectric materials directly convert the elastic energy to the electric energy, and thus have a great advantage in scavenging vibrational energy for simplicity in device structure with relatively high power density. This paper provides an overview on the research of piezoelectric materials in energy harvesting in recent decades, from basics of piezoelectricity and working principle of energy harvesting with piezoelectric materials, to the progress of development of high-performance piezoelectrics including ceramics, single crystals and polymers, then to experimental attempts on the device fabrication and optimization, finally to perspective applications of piezoelectric energy harvesting(PEH). The criteria for selection of materials for PEH applications are introduced. Not only the figure of merit but also maximum allowable stress of materials are taken into account in the evaluation of their potential in achieving high energy density and output power density. The influence of the device configuration on the performance is also acknowledged and discussed. The magnitude and distribution of induced stress in the piezoelectric unit upon excitation by the vibration source play an important role in determining the output power density and can be tuned via proper design of device configuration without changing its resonant frequency. Approaches to address the issue of frequency match accompanying with the resonant mode are illustrated with literature examples. Usage of PEH devices can be extended to a variety of vibration sources in everyday life as well as in nature. Some appealing applications of PEH, such as in implantable and wearable devices, are reviewed.
文摘The fact that InN has a direct bandgap of 0.75eV enables InN-based nitrides devices to cover the wavelength range from UV region to 1.8μm, therefore, emerging as a new material system for optical communication applications.
文摘A long-term field experiment on organic material application and crop rotation with green manure crops has been conducted since 1976 at Lopburi Agricultural Research and Development Center,Department of Agriculture,Lop Buri Province,Thailand,to clarify the effect of organic materials and green manure crop on soil organic carbon changes.The stock change factors that stand for the relative change of soil organic carbon on the carbon stock in a reference condition(native vegetation that is not degraded or improved).Stock change factor for input of organic matter(F1),representing different levels of C input to soil such as organic material application,crop residue treatment and green manure crop cultivation,was computed with the present field experimental results.While the computed F1 of"High input with manure"was within the range of IPCC default F1 value,some of the computed F1 of"High input without manure"was much higher than the IPCC default though it was varied due to the biomass production and nutrient contents of the green manure crops planted as the second crops after corn.Therefore,the F1 computed by field experimental results can contribute to more accurate estimation of SOC changes in farm land especially in Southeast Asia because the default F1 mostly depends on the experimental data in temperate zones.Moreover,the field experiment has focused the effect of reduced tillage practices on SOC changes and corn yield since 2011.The results of the experiment will be used to compute Stock change factor for management regime(FMC)which represents the effects of tillage operations.
基金Project supported by the National Natural Science Foundation of China(Nos.61376007,61674137)the National Key Research and Development Program of China(No.2016YFB0400802)
文摘Two-dimensional（2D） materials have recently received a great deal of attention due to their unique structures and fascinating properties,as well as their potential applications.2D hexagonal boron nitride（2D hBN）,an insulator with excellent thermal stability,chemical inertness,and unique electronic and optical properties,and a band gap of 5.97 e V,is considered to be an ideal candidate for integration with other 2D materials.Nevertheless,the controllable growth of high-quality 2D h-BN is still a great challenge.A comprehensive overview of the progress that has been made in the synthesis of 2D h-BN is presented,highlighting the advantages and disadvantages of various synthesis approaches.In addition,the electronic,optical,thermal,and mechanical properties,heterostructures,and related applications of 2D h-BN are discussed.
