Fluoride ferrous(FeF_(2))is viewed as a promising conversion cathode material for next-generation lithiumion batteries(LIBs)due to its high theoretical specific capacity and low cost.Unfortunately,issues such as poor ...Fluoride ferrous(FeF_(2))is viewed as a promising conversion cathode material for next-generation lithiumion batteries(LIBs)due to its high theoretical specific capacity and low cost.Unfortunately,issues such as poor intrinsic conductivity,iron dissolution,and phase separation hinder the application of FeF_(2)in highenergy cathodes.Here,a pressure-induced morphology control method is designed to prepare coralloidlike FeF_(2)nanocrystals with nitrogen-rich carbon coating(c-FeF_(2)@NC).The coralloid-like interconnected crystal structure of c-FeF_(2)@NC contributes to reducing interfacial resistance and enhancing the topotactic transformation during the conversion reaction,and the nitrogen-rich carbon(NC)coating can enhance interfacial stability and kinetic performance.When used as a conversion cathode for LIBs,c-FeF_(2)@NC exhibits a high initial reversible capacity of 503.57 mA h g^(-1)and excellent cycling stability of497.61 m A h g^(-1)with a low capacity decay of 1.19%over 50 cycles at 0.1 A/g.Even at 1 A/g,a stable capacity of 263.78 mA h g^(-1)can still be retained after 200 cycles.The capability of c-FeF_(2)@NC as a conversion cathode for sodium-ion batteries(SIBs)was also evaluated to expand its field of application.Furthermore,two kinds of full batteries have been assembled by employing c-FeF_(2)@NC as cathodes and quantitative limited-Li(LLi)and pre-lithiated reduced graphene oxide(PGO)as anodes,respectively,to envisage the feasibility of practical applications of conversion materials.展开更多
Volume variation is an uncertainty element which affects timber processing. We studied the volume variation of logs caused by quality defects in traditional timber processing and set up an optimization approach,using ...Volume variation is an uncertainty element which affects timber processing. We studied the volume variation of logs caused by quality defects in traditional timber processing and set up an optimization approach,using a robust optimization method. We used total number of acceptable boards produced to study the relationship between board thickness and raw material logs, using a heuristic search algorithm to control the variation of board volume to improve the output of boards, reduce the quantity of by-products, and lower production costs. The robust optimization method can effectively control the impact of volume variations in timber processing, reduce cutting waste as far as possible using incremental processing and increase profits, maximize the utilization ratio of timber, prevent waste in processing, cultivate the productive type of tree species and save forest resources.展开更多
This paper carries out a questionnaire survey on 30 quality inspection institutions at the level of the Ministry of Agriculture,and based on systematic analysis,analyzes the causes of difficulties in personal submissi...This paper carries out a questionnaire survey on 30 quality inspection institutions at the level of the Ministry of Agriculture,and based on systematic analysis,analyzes the causes of difficulties in personal submission of samples for inspection from six aspects in order to meet the real needs of personal submission of agricultural product samples for inspection under the new situation. In accordance with the actual situation of China's current regulatory system and quality control system,this paper sets forth the relevant recommendations to correctly guide the personal submission of samples for inspection and promote the development of quality inspection system.展开更多
Graphene has been widely used for electrical energy storage and its performances could be further improved by heteroatom doping.How to prepare doped graphene efficiently and economically remains a significant challeng...Graphene has been widely used for electrical energy storage and its performances could be further improved by heteroatom doping.How to prepare doped graphene efficiently and economically remains a significant challenge.Here,we propose a flash-assisted doping method to produce nitrogen-and sulfur-doped graphene(N-rGO and S-rGO).Using this method,graphene oxide(GO)is reduced to few-layer graphene(rGO)in seconds without the use of reductants,accompanied with a high doping efficiency.Particularly,the as-synthesized N-rGO with a high N content of 12.75 at.%used as potassium-ion battery(KIB)anode exhibits ultrafast K+-transport kinetics and superior K^(+)-storage capability.Quantitative kinetics analysis and theoretical simulation are used to reveal the mechanism of transportation and storage of K^(+)in N-rGO.展开更多
Organic color-tunable phosphorescent materials depend upon multiple emission centers to achieve colortunable phosphorescence with changes in excitation wavelength,temperature,time,and other external factors.Organic co...Organic color-tunable phosphorescent materials depend upon multiple emission centers to achieve colortunable phosphorescence with changes in excitation wavelength,temperature,time,and other external factors.Organic color-tunable phosphorescent materials are becoming increasingly popular due to their potential applications in anticounterfeiting,encryption and sensing.This brief review focuses on the formation of multiple emission centers in organic color-tunable phosphorescent materials and how to ensure that these multiple emission centers can simultaneously emit.In the future,materials with a large color tunable ranges,increased efficiency,and relatively long lives will be developed.展开更多
Dear Editors,The quantitative interpretation of the particle and antiparticle correlation results depends critically on understanding the role of Coulomb interaction of the measured pairs of particles with each other,...Dear Editors,The quantitative interpretation of the particle and antiparticle correlation results depends critically on understanding the role of Coulomb interaction of the measured pairs of particles with each other,as well as the Coulomb interaction of the pair with the system of remaining particles[1-7].展开更多
Digital lightning is an important thematic branch of the digital earth.Lightning data are complex,momentary,discrete,dynamic and spatio-temporal in nature.Hence,making great progress in their management,analysis and s...Digital lightning is an important thematic branch of the digital earth.Lightning data are complex,momentary,discrete,dynamic and spatio-temporal in nature.Hence,making great progress in their management,analysis and service is challenging.Many studies have been directed towards this field all over the world.Some different relevant systems are currently available.However,most of them focus on a single or a few aspects of lightning applications,rather than taking an overall account of lightning detection,management,analysis and service from the strategic perspective of the digital earth.Lightning disaster also demands a better developed spatial information technology in this field than at present.The idea of the digital earth offers a reasonable scheme to address these issues.Based on reviews of the concept,development and progress of the digital earth,an integrated technical framework of a digital lightning prototype system(DLPS)is proposed,including its data,functions and implementation of subsystems,which aims at the facilitation,management,accessing,visualisation,application,release and sharing of lightning data.Some key technologies are also carefully discussed to facilitate the construction of the DLPS.This framework could provide a helpful guide to future lightning research and hazard mitigation,as well as enrich connotation on the digital earth.So far,there are still many difficulties in multilevel grid construction that need to be solved.展开更多
In order to suppress the battery aging of electric vehicles(EVs),a multi-objective optimization function is established to describe the battery aging behavior based on a high-precision battery aging model,and the stat...In order to suppress the battery aging of electric vehicles(EVs),a multi-objective optimization function is established to describe the battery aging behavior based on a high-precision battery aging model,and the state–space equation is then constructed to reveal the intrinsic relationship between vehicle speed,acceleration,and battery state-of-charge(SOC).The constructed optimization model is solved by using a sequential quadratic programming(SQP)algorithm,and based on the model predictive control(MPC)theory,the efficient real-time control of vehicle speed is achieved.Simulation results show that the developed strategy extends the battery life by 10.33%compared to the baseline strategy when the traffic flow is not involved.In the case of involving the traffic flow,the optimization results of battery aging improves as the look-ahead time period increases,while the computational burden increases.The results show that the developed strategy reduces the battery aging of the target vehicle by 33.02%compared to the preceding vehicle while meeting the real-time requirement.展开更多
基金supported by Foundation for the Sichuan University and Zigong City Joint research project(2021CDZG-2)the Foundation for the Sichuan University and Yibin City Strategic Cooperation Project(2020CDYB-32)the Guangxi Key Laboratory of Low Carbon Energy Material(2020GKLLCEM02)。
文摘Fluoride ferrous(FeF_(2))is viewed as a promising conversion cathode material for next-generation lithiumion batteries(LIBs)due to its high theoretical specific capacity and low cost.Unfortunately,issues such as poor intrinsic conductivity,iron dissolution,and phase separation hinder the application of FeF_(2)in highenergy cathodes.Here,a pressure-induced morphology control method is designed to prepare coralloidlike FeF_(2)nanocrystals with nitrogen-rich carbon coating(c-FeF_(2)@NC).The coralloid-like interconnected crystal structure of c-FeF_(2)@NC contributes to reducing interfacial resistance and enhancing the topotactic transformation during the conversion reaction,and the nitrogen-rich carbon(NC)coating can enhance interfacial stability and kinetic performance.When used as a conversion cathode for LIBs,c-FeF_(2)@NC exhibits a high initial reversible capacity of 503.57 mA h g^(-1)and excellent cycling stability of497.61 m A h g^(-1)with a low capacity decay of 1.19%over 50 cycles at 0.1 A/g.Even at 1 A/g,a stable capacity of 263.78 mA h g^(-1)can still be retained after 200 cycles.The capability of c-FeF_(2)@NC as a conversion cathode for sodium-ion batteries(SIBs)was also evaluated to expand its field of application.Furthermore,two kinds of full batteries have been assembled by employing c-FeF_(2)@NC as cathodes and quantitative limited-Li(LLi)and pre-lithiated reduced graphene oxide(PGO)as anodes,respectively,to envisage the feasibility of practical applications of conversion materials.
基金supported by the Fundamental Research Funds for the Central Universities(Project No.2572015CB06)Nature Science Foundation of Heilongjiang Province(LC201407)
文摘Volume variation is an uncertainty element which affects timber processing. We studied the volume variation of logs caused by quality defects in traditional timber processing and set up an optimization approach,using a robust optimization method. We used total number of acceptable boards produced to study the relationship between board thickness and raw material logs, using a heuristic search algorithm to control the variation of board volume to improve the output of boards, reduce the quantity of by-products, and lower production costs. The robust optimization method can effectively control the impact of volume variations in timber processing, reduce cutting waste as far as possible using incremental processing and increase profits, maximize the utilization ratio of timber, prevent waste in processing, cultivate the productive type of tree species and save forest resources.
基金Supported by Young Start-up Funding of Jilin Agricultural University(201229)Key National Risk Assessment Project for the Quality and Safety of Agricultural Products(GJFP2014010)
文摘This paper carries out a questionnaire survey on 30 quality inspection institutions at the level of the Ministry of Agriculture,and based on systematic analysis,analyzes the causes of difficulties in personal submission of samples for inspection from six aspects in order to meet the real needs of personal submission of agricultural product samples for inspection under the new situation. In accordance with the actual situation of China's current regulatory system and quality control system,this paper sets forth the relevant recommendations to correctly guide the personal submission of samples for inspection and promote the development of quality inspection system.
基金This work was supported by the Excellent Young Scholar Research Foundation of Sichuan University(No.2017SCU04A07)Sichuan Science and Technology Program(No.2019YFG0218).
文摘Graphene has been widely used for electrical energy storage and its performances could be further improved by heteroatom doping.How to prepare doped graphene efficiently and economically remains a significant challenge.Here,we propose a flash-assisted doping method to produce nitrogen-and sulfur-doped graphene(N-rGO and S-rGO).Using this method,graphene oxide(GO)is reduced to few-layer graphene(rGO)in seconds without the use of reductants,accompanied with a high doping efficiency.Particularly,the as-synthesized N-rGO with a high N content of 12.75 at.%used as potassium-ion battery(KIB)anode exhibits ultrafast K+-transport kinetics and superior K^(+)-storage capability.Quantitative kinetics analysis and theoretical simulation are used to reveal the mechanism of transportation and storage of K^(+)in N-rGO.
基金financially supported by the Shandong Provincial Natural Science Foundation(Nos.ZR2019YQ19 and ZR2019BEM018)the Project of Shandong Province Higher Educational Science and Technology Program(No.2019KJA026)the National Natural Science Foundation of China(Nos.51403113 and 52072193)。
文摘Organic color-tunable phosphorescent materials depend upon multiple emission centers to achieve colortunable phosphorescence with changes in excitation wavelength,temperature,time,and other external factors.Organic color-tunable phosphorescent materials are becoming increasingly popular due to their potential applications in anticounterfeiting,encryption and sensing.This brief review focuses on the formation of multiple emission centers in organic color-tunable phosphorescent materials and how to ensure that these multiple emission centers can simultaneously emit.In the future,materials with a large color tunable ranges,increased efficiency,and relatively long lives will be developed.
基金supported by the National Natural Science Foundation of China(Grant Nos.11147016,11547109,61275117 and 11304086)the Natural Science Foundation of Heilong/iang Province of China(Grant No.QC2014C004)the Key Laboratory of Electronics Engineering,Heilongjiang University,China(Grant No.DZZD200801)
文摘Dear Editors,The quantitative interpretation of the particle and antiparticle correlation results depends critically on understanding the role of Coulomb interaction of the measured pairs of particles with each other,as well as the Coulomb interaction of the pair with the system of remaining particles[1-7].
基金The authors would like to appreciate the financial support for this study from the National Key Technology R&D Program of China(Grant#2008BAC36B01)the Program for New Century Excellent Talent of Ministry of Education of China(Grant#NCET-07-0340)+1 种基金the Natural Science Foundation for Outstanding Scholarship of Hubei Province in China(Grant#2008CDB364)the National Natural Science Foundation of China(Grant#41072199 and 40672179).
文摘Digital lightning is an important thematic branch of the digital earth.Lightning data are complex,momentary,discrete,dynamic and spatio-temporal in nature.Hence,making great progress in their management,analysis and service is challenging.Many studies have been directed towards this field all over the world.Some different relevant systems are currently available.However,most of them focus on a single or a few aspects of lightning applications,rather than taking an overall account of lightning detection,management,analysis and service from the strategic perspective of the digital earth.Lightning disaster also demands a better developed spatial information technology in this field than at present.The idea of the digital earth offers a reasonable scheme to address these issues.Based on reviews of the concept,development and progress of the digital earth,an integrated technical framework of a digital lightning prototype system(DLPS)is proposed,including its data,functions and implementation of subsystems,which aims at the facilitation,management,accessing,visualisation,application,release and sharing of lightning data.Some key technologies are also carefully discussed to facilitate the construction of the DLPS.This framework could provide a helpful guide to future lightning research and hazard mitigation,as well as enrich connotation on the digital earth.So far,there are still many difficulties in multilevel grid construction that need to be solved.
基金Research Start-Up Funding of Chongqing University under Grant 02090011044160.
文摘In order to suppress the battery aging of electric vehicles(EVs),a multi-objective optimization function is established to describe the battery aging behavior based on a high-precision battery aging model,and the state–space equation is then constructed to reveal the intrinsic relationship between vehicle speed,acceleration,and battery state-of-charge(SOC).The constructed optimization model is solved by using a sequential quadratic programming(SQP)algorithm,and based on the model predictive control(MPC)theory,the efficient real-time control of vehicle speed is achieved.Simulation results show that the developed strategy extends the battery life by 10.33%compared to the baseline strategy when the traffic flow is not involved.In the case of involving the traffic flow,the optimization results of battery aging improves as the look-ahead time period increases,while the computational burden increases.The results show that the developed strategy reduces the battery aging of the target vehicle by 33.02%compared to the preceding vehicle while meeting the real-time requirement.