In recent years,perovskite solar cells(PSCs)have garnered significant attention as a potential mainstream technology in the future photovol-taic(PV)market.This is primarily attributed to their salient advantages inclu...In recent years,perovskite solar cells(PSCs)have garnered significant attention as a potential mainstream technology in the future photovol-taic(PV)market.This is primarily attributed to their salient advantages including high efficiency,low cost,and ease of preparation.Nota-bly,the power conversion efficiency(PCE)of PSCs has experienced a remarkable increase from 3.8%in 2009 to over 26%at present.Conse-quently,the adoption of roll-to-roll(R2R)technology for PSCs is considered a crucial step towards their successful commercialization.This arti-de reviews the diverse substrates,scalable deposition techniques(such as solution-based knife-coating and spraying technology),and optimiza.tion procedures employed in recent years to enhance device performance within the R2R process.Additionally,novel perspectives are presented to enrich the existing knowledge in this field.展开更多
A model of quantum thermoacoustic refrigeration micro-cycle(QTARMC)is established in which heat leakage is considered.A single particle contained in a one-dimensional harmonic potential well is studied,and the system ...A model of quantum thermoacoustic refrigeration micro-cycle(QTARMC)is established in which heat leakage is considered.A single particle contained in a one-dimensional harmonic potential well is studied,and the system consists of countless replicas.Each particle is confined in its own potential well,whose occupation probabilities can be expressed by the thermal equilibrium Gibbs distributions.Based on the Schrodinger equation,the expressions of coefficient of performance(COP)and cooling rate for the refrigerator are obtained.Effects of heat leakage on the optimal performance are discussed.The optimal performance region of the refrigeration cycle is obtained by the using ofΩobjective function.The results obtained can enrich the thermoacoustic theory and expand the application of quantum thermodynamics.展开更多
Satellite constellation design for space optical systems is essentially a multiple-objective optimization problem. In this work, to tackle this challenge, we first categorize the performance metrics of the space optic...Satellite constellation design for space optical systems is essentially a multiple-objective optimization problem. In this work, to tackle this challenge, we first categorize the performance metrics of the space optical system by taking into account the system tasks（i.e., target detection and tracking）. We then propose a new non-dominated sorting genetic algorithm（NSGA） to maximize the system surveillance performance. Pareto optimal sets are employed to deal with the conflicts due to the presence of multiple cost functions. Simulation results verify the validity and the improved performance of the proposed technique over benchmark methods.展开更多
Converting CO_(2)into valuable carbon products can effectively address the current energy crisis and environmental issues.Electrocatalytic CO_(2)reduction(ECR),powered by sustainable electricity,is an ideal approach t...Converting CO_(2)into valuable carbon products can effectively address the current energy crisis and environmental issues.Electrocatalytic CO_(2)reduction(ECR),powered by sustainable electricity,is an ideal approach to reduce carbon emissions and promote the carbon cycle.Electrocatalytic CO_(2)reduction,powered by sustainable electricity,is an ideal approach to reduce carbon emissions and promote the carbon cycle.However,CO_(2)is a thermodynamically inert molecule,making it challenging to obtain the desired products through ECR.Additionally,ECR involves a complex process of multi-electron and proton transfer,requiring different amounts of electrons and protons to gradually form various reduction products.This complexity highlights the urgent need to develop advanced catalysts to overcome the slow reaction kinetics and intricate coupling pathways associated with ECR.Single-atom catalysts(SACs)have emerged as a cutting-edge frontier in heterogeneous catalysis and find extensive application in ECR due to their high atom utilization,excellent activity,and selectivity.SACs defy the traditional design concept of nanoparticle catalysts and exhibit catalytic activity at the atomic level,maximizing their efficiency.Another advantage of SACs lies in their ability to tune the electronic structure of the active central atom through ligand atoms.However,while SACs provide separate metal active sites with no crosstalk between adjacent metal atoms,they do form strong chemical bonding interactions with the support.Currently,SACs for ECR still face challenges such as low selectivity and the goal of achieving high-value product generation.Therefore,optimizing the performance of SACs is of paramount importance.Considering the extensive exploration and application of SACs in the field of ECR,this review aims to summarize the research progress in SAC applications for ECR.It also addresses the challenges and prospects associated with SACs in ECR applications.Specifically,the review covers:(1)the introduction of the ECR reaction mechanism,(2)common preparation strategies for SACs,and(3)the application of SACs in novel devices based on Zn-CO_(2)batteries.Finally,the review discusses the challenges and opportunities that SACs present in the context of ECR.展开更多
Impressive advances in space technology are enabling complex missions, with potentially significant and long term impacts on human life and activities. In the vision of future space exploration, communication links am...Impressive advances in space technology are enabling complex missions, with potentially significant and long term impacts on human life and activities. In the vision of future space exploration, communication links among planets, satel ites, spacecrafts and crewed vehicles wil be designed according to a new paradigm, known as the disruption tolerant networking. In this scenario, space channel peculiarities impose a massive reengineering of many of the protocols usually adopted in terrestrial networks; among them, security solutions are to be deeply reviewed, and tailored to the specific space requirements. Security is to be provided not only to the payload data exchanged on the network, but also to the telecommands sent to a spacecraft, along possibly differentiated paths. Starting from the secure space telecommand design developed by the Consultative Committee for Space Data Systems as a response to agency-based requirements, an adaptive link layer security architecture is proposed to address some of the chal enges for future space networks. Based on the analysis of the communication environment and the error diffusion properties of the authentication algorithms, a suitable mechanism is proposed to classify frame retransmission requests on the basis of the originating event （error or security attack） and reduce the impact of security operations. An adaptive algorithm to optimize the space control protocol, based on estimates of the time varying space channel, is also presented. The simulation results clearly demonstrate that the proposed architecture is feasible and efficient, especially when facing malicious attacks against frame transmission.展开更多
In distributed parallel server system, location and redundancy of repficas have great influence on availability and efficiency of the system. In order to improve availability and efficiency of the system, two phase de...In distributed parallel server system, location and redundancy of repficas have great influence on availability and efficiency of the system. In order to improve availability and efficiency of the system, two phase decision algorithm of replica allocation is proposed. The algorithm which makes use of auto-regression model dynamically predicts the future count of READ and WRITE operation, and then determines location and redundancy of replicas by considering availability, CPU and bands of the network. The algorithm can not only ensure the requirement of availability, but also reduce the system resources consumed by all the operations in a great scale. Analysis and test show that communication complexity and time complexity of the algorithm satisfy O（n）, resource optimizing scale increases with the increase of READ count.展开更多
文摘In recent years,perovskite solar cells(PSCs)have garnered significant attention as a potential mainstream technology in the future photovol-taic(PV)market.This is primarily attributed to their salient advantages including high efficiency,low cost,and ease of preparation.Nota-bly,the power conversion efficiency(PCE)of PSCs has experienced a remarkable increase from 3.8%in 2009 to over 26%at present.Conse-quently,the adoption of roll-to-roll(R2R)technology for PSCs is considered a crucial step towards their successful commercialization.This arti-de reviews the diverse substrates,scalable deposition techniques(such as solution-based knife-coating and spraying technology),and optimiza.tion procedures employed in recent years to enhance device performance within the R2R process.Additionally,novel perspectives are presented to enrich the existing knowledge in this field.
基金Project(51176143)supported by the National Natural Science Foundation of ChinaProject(K201919)supported by the Scientific Research Foundation of Wuhan Institute of TechnologyChina。
文摘A model of quantum thermoacoustic refrigeration micro-cycle(QTARMC)is established in which heat leakage is considered.A single particle contained in a one-dimensional harmonic potential well is studied,and the system consists of countless replicas.Each particle is confined in its own potential well,whose occupation probabilities can be expressed by the thermal equilibrium Gibbs distributions.Based on the Schrodinger equation,the expressions of coefficient of performance(COP)and cooling rate for the refrigerator are obtained.Effects of heat leakage on the optimal performance are discussed.The optimal performance region of the refrigeration cycle is obtained by the using ofΩobjective function.The results obtained can enrich the thermoacoustic theory and expand the application of quantum thermodynamics.
文摘Satellite constellation design for space optical systems is essentially a multiple-objective optimization problem. In this work, to tackle this challenge, we first categorize the performance metrics of the space optical system by taking into account the system tasks（i.e., target detection and tracking）. We then propose a new non-dominated sorting genetic algorithm（NSGA） to maximize the system surveillance performance. Pareto optimal sets are employed to deal with the conflicts due to the presence of multiple cost functions. Simulation results verify the validity and the improved performance of the proposed technique over benchmark methods.
文摘Converting CO_(2)into valuable carbon products can effectively address the current energy crisis and environmental issues.Electrocatalytic CO_(2)reduction(ECR),powered by sustainable electricity,is an ideal approach to reduce carbon emissions and promote the carbon cycle.Electrocatalytic CO_(2)reduction,powered by sustainable electricity,is an ideal approach to reduce carbon emissions and promote the carbon cycle.However,CO_(2)is a thermodynamically inert molecule,making it challenging to obtain the desired products through ECR.Additionally,ECR involves a complex process of multi-electron and proton transfer,requiring different amounts of electrons and protons to gradually form various reduction products.This complexity highlights the urgent need to develop advanced catalysts to overcome the slow reaction kinetics and intricate coupling pathways associated with ECR.Single-atom catalysts(SACs)have emerged as a cutting-edge frontier in heterogeneous catalysis and find extensive application in ECR due to their high atom utilization,excellent activity,and selectivity.SACs defy the traditional design concept of nanoparticle catalysts and exhibit catalytic activity at the atomic level,maximizing their efficiency.Another advantage of SACs lies in their ability to tune the electronic structure of the active central atom through ligand atoms.However,while SACs provide separate metal active sites with no crosstalk between adjacent metal atoms,they do form strong chemical bonding interactions with the support.Currently,SACs for ECR still face challenges such as low selectivity and the goal of achieving high-value product generation.Therefore,optimizing the performance of SACs is of paramount importance.Considering the extensive exploration and application of SACs in the field of ECR,this review aims to summarize the research progress in SAC applications for ECR.It also addresses the challenges and prospects associated with SACs in ECR applications.Specifically,the review covers:(1)the introduction of the ECR reaction mechanism,(2)common preparation strategies for SACs,and(3)the application of SACs in novel devices based on Zn-CO_(2)batteries.Finally,the review discusses the challenges and opportunities that SACs present in the context of ECR.
基金supported by the National Natural Science Fundation of China(61101073)
文摘Impressive advances in space technology are enabling complex missions, with potentially significant and long term impacts on human life and activities. In the vision of future space exploration, communication links among planets, satel ites, spacecrafts and crewed vehicles wil be designed according to a new paradigm, known as the disruption tolerant networking. In this scenario, space channel peculiarities impose a massive reengineering of many of the protocols usually adopted in terrestrial networks; among them, security solutions are to be deeply reviewed, and tailored to the specific space requirements. Security is to be provided not only to the payload data exchanged on the network, but also to the telecommands sent to a spacecraft, along possibly differentiated paths. Starting from the secure space telecommand design developed by the Consultative Committee for Space Data Systems as a response to agency-based requirements, an adaptive link layer security architecture is proposed to address some of the chal enges for future space networks. Based on the analysis of the communication environment and the error diffusion properties of the authentication algorithms, a suitable mechanism is proposed to classify frame retransmission requests on the basis of the originating event （error or security attack） and reduce the impact of security operations. An adaptive algorithm to optimize the space control protocol, based on estimates of the time varying space channel, is also presented. The simulation results clearly demonstrate that the proposed architecture is feasible and efficient, especially when facing malicious attacks against frame transmission.
文摘In distributed parallel server system, location and redundancy of repficas have great influence on availability and efficiency of the system. In order to improve availability and efficiency of the system, two phase decision algorithm of replica allocation is proposed. The algorithm which makes use of auto-regression model dynamically predicts the future count of READ and WRITE operation, and then determines location and redundancy of replicas by considering availability, CPU and bands of the network. The algorithm can not only ensure the requirement of availability, but also reduce the system resources consumed by all the operations in a great scale. Analysis and test show that communication complexity and time complexity of the algorithm satisfy O（n）, resource optimizing scale increases with the increase of READ count.
