The construction of extraterrestrial bases has become a new goal in the active exploration of deep space.Among the construction techniques,in situ resource-based construction is one of the most promising because of it...The construction of extraterrestrial bases has become a new goal in the active exploration of deep space.Among the construction techniques,in situ resource-based construction is one of the most promising because of its good sustainability and acceptable economic cost,triggering the development of various types of extraterrestrial construction materials.A comprehensive survey and comparison of materials from the perspective of performance was conducted to provide suggestions for material selection and optimization.Thirteen types of typical construction materials are discussed in terms of their reliability and applicability in extreme extraterrestrial environment.Mechanical,thermal and optical,and radiation-shielding properties are considered.The influencing factors and optimization methods for these properties are analyzed.From the perspective of material properties,the existing challenges lie in the comprehensive,long-term,and real characterization of regolith-based construction materials.Correspondingly,the suggested future directions include the application of high-throughput characterization methods,accelerated durability tests,and conducting extraterrestrial experiments.展开更多
Battery safety has attracted considerable attention worldwide due to the rapid development of wearable electronics and the steady increase in the production and use of electric vehicles.As battery failures are often a...Battery safety has attracted considerable attention worldwide due to the rapid development of wearable electronics and the steady increase in the production and use of electric vehicles.As battery failures are often associated with mechanical-thermal coupled behaviors,protective shielding materials with excellent mechanical robustness and flame-retardant properties are highly desired to mitigate thermal runaway.However,most of the thermal insulating materials are not strong enough to protect batteries from mechanical abuse,which is one of the most critical scenarios with catastrophic consequences.Here,inspired by wood,we have developed an effective approach to engineer a hierarchical nanocomposite via self-assembly of calcium silicate hydrate and polyvinyl alcohol polymer chains(referred as CSH wood).The versatile protective material CSH wood demonstrates an unprecedented combination of light weight(0.018 g cm-3),high stiffness(204 MPa in the axial direction),negative Poisson's ratio(-0.15),remarkable toughness(6.67×105 J m-3),superior thermal insulation(0.0204 W m-1 K-1 in the radial direction),and excellent fire retardancy(UL94-V0).When applied as a protective cover or a protective layer within battery packages,the tough CSH wood can resist high-impact load and block heat diffusion to block or delay the spread of fire,therefore significantly reducing the risk of property damage or bodily injuries caused by battery explosions.This work provides new pathways for fabricating advanced thermal insulating materials with large scalability and demonstrates great potential for the protection of electronic devices.展开更多
The path planning of Unmanned Aerial Vehicle(UAV)is a critical issue in emergency communication and rescue operations,especially in adversarial urban environments.Due to the continuity of the flying space,complex buil...The path planning of Unmanned Aerial Vehicle(UAV)is a critical issue in emergency communication and rescue operations,especially in adversarial urban environments.Due to the continuity of the flying space,complex building obstacles,and the aircraft's high dynamics,traditional algorithms cannot find the optimal collision-free flying path between the UAV station and the destination.Accordingly,in this paper,we study the fast UAV path planning problem in a 3D urban environment from a source point to a target point and propose a Three-Step Experience Buffer Deep Deterministic Policy Gradient(TSEB-DDPG)algorithm.We first build the 3D model of a complex urban environment with buildings and project the 3D building surface into many 2D geometric shapes.After transformation,we propose the Hierarchical Learning Particle Swarm Optimization(HL-PSO)to obtain the empirical path.Then,to ensure the accuracy of the obtained paths,the empirical path,the collision information and fast transition information are stored in the three experience buffers of the TSEB-DDPG algorithm as dynamic guidance information.The sampling ratio of each buffer is dynamically adapted to the training stages.Moreover,we designed a reward mechanism to improve the convergence speed of the DDPG algorithm for UAV path planning.The proposed TSEB-DDPG algorithm has also been compared to three widely used competitors experimentally,and the results show that the TSEB-DDPG algorithm can archive the fastest convergence speed and the highest accuracy.We also conduct experiments in real scenarios and compare the real path planning obtained by the HL-PSO algorithm,DDPG algorithm,and TSEB-DDPG algorithm.The results show that the TSEBDDPG algorithm can archive almost the best in terms of accuracy,the average time of actual path planning,and the success rate.展开更多
In order to secure the massive heterogeneous medical data for the complex scenarios and improve the information sharing efficiency in healthcare system,a distributed medical data ledger model(DMDL)is proposed in this ...In order to secure the massive heterogeneous medical data for the complex scenarios and improve the information sharing efficiency in healthcare system,a distributed medical data ledger model(DMDL)is proposed in this paper.This DMDL model has adopted the blockchain technology including the function decoupling,the distributed consensus,smart contract as well as multi-channel communication structure of consortium blockchain.The DMDL model not only has high adaptability,but also meets the requirements of the medical treatment processes which generally involve multientities,highly private information and secure transaction.The steps for processing the medical data are also introduced.Additionally,the methods for the definition and application of the DMDL model are presented for three specific medical scenarios,i.e.,the management of the heterogeneous data,copyright protection for medical data and the secure utilization of sensitive data.The advantage of the proposed DMDL model is demonstrated by comparing with the models which are being currently adopted in healthcare system.展开更多
Architecturat heritage conservation is an important field in architectural research. The Hui-styte vernacutar dwetling is an essentialarchitectural heritage of China. Its hollow watt system, with horsehead-like upper ...Architecturat heritage conservation is an important field in architectural research. The Hui-styte vernacutar dwetling is an essentialarchitectural heritage of China. Its hollow watt system, with horsehead-like upper corners, is a distinct architecturat feature that is worth preserving. However, the thermat performance of the hollow watt is relatively poor by today＇s standard. The current study developed a novel approach, whereby foam concrete was used to fill the voids inside the holtow watt to improve its thermat resistance. This approach was deemed cost effective, easy to learn, and capable of preserving the architectural integrity of the watt. Different types of foam concrete were prepared and tested. Testing results showed that the material properties of foam concrete are suitabte for thermaUy upgrading the hollow watt system. Ctimate chamber testing was conducted to investigate the effectiveness of the proposed thermat upgrading strategy. The testing resutts suggested that tilting the voids with foam concrete can effectively improve the overall thermal resistance of the holtow watt system by 24%, which is almost equal to the overall thermal resistance when using the more expensive commercial inorganic stucco system.展开更多
Thermo-responsive hydrogels can dynamically modulate incident light,providing a broad prospect for development of smart windows,which are of pivotal importance for energy conservation in buildings.However,these hydrog...Thermo-responsive hydrogels can dynamically modulate incident light,providing a broad prospect for development of smart windows,which are of pivotal importance for energy conservation in buildings.However,these hydrogels normally exhibit slow response speed and tend to contract over extended phase transition,compromising structural integrity of smart windows.In this study,a solid–liquid switchable thermochromic hydrogel,denoted as SL-PNIPAm,was synthesized by cross-linking PNIPAm with AMEO through dynamic imine bonds.Due to its distinctive solid–liquid transformation characteristics,SL-PNIPAm demonstrates rapid response time(within 5 s)and retains structural integrity without undergoing shrinkage during heating/cooling and freezing/thawing cycles.展开更多
基金supported by the National Key Research and Development Program of China(2023YFB3711300 and 2021YFF0500300)the Strategic Research and Consulting Project of the Chinese Academy of Engineering(2023-XZ-90 and 2023-JB-09-10)the National Key Research and Development Program of China(2021YFF0500300).
文摘The construction of extraterrestrial bases has become a new goal in the active exploration of deep space.Among the construction techniques,in situ resource-based construction is one of the most promising because of its good sustainability and acceptable economic cost,triggering the development of various types of extraterrestrial construction materials.A comprehensive survey and comparison of materials from the perspective of performance was conducted to provide suggestions for material selection and optimization.Thirteen types of typical construction materials are discussed in terms of their reliability and applicability in extreme extraterrestrial environment.Mechanical,thermal and optical,and radiation-shielding properties are considered.The influencing factors and optimization methods for these properties are analyzed.From the perspective of material properties,the existing challenges lie in the comprehensive,long-term,and real characterization of regolith-based construction materials.Correspondingly,the suggested future directions include the application of high-throughput characterization methods,accelerated durability tests,and conducting extraterrestrial experiments.
基金the financial support from the National Key Research and Development Program of China(No.2021YFF0500802)the National Natural Science Foundation of China(No.51890904,No.52022022,and No.52278247)the Scientific Research and Innovation Plan of Jiangsu Province(KYCX21_0090)。
文摘Battery safety has attracted considerable attention worldwide due to the rapid development of wearable electronics and the steady increase in the production and use of electric vehicles.As battery failures are often associated with mechanical-thermal coupled behaviors,protective shielding materials with excellent mechanical robustness and flame-retardant properties are highly desired to mitigate thermal runaway.However,most of the thermal insulating materials are not strong enough to protect batteries from mechanical abuse,which is one of the most critical scenarios with catastrophic consequences.Here,inspired by wood,we have developed an effective approach to engineer a hierarchical nanocomposite via self-assembly of calcium silicate hydrate and polyvinyl alcohol polymer chains(referred as CSH wood).The versatile protective material CSH wood demonstrates an unprecedented combination of light weight(0.018 g cm-3),high stiffness(204 MPa in the axial direction),negative Poisson's ratio(-0.15),remarkable toughness(6.67×105 J m-3),superior thermal insulation(0.0204 W m-1 K-1 in the radial direction),and excellent fire retardancy(UL94-V0).When applied as a protective cover or a protective layer within battery packages,the tough CSH wood can resist high-impact load and block heat diffusion to block or delay the spread of fire,therefore significantly reducing the risk of property damage or bodily injuries caused by battery explosions.This work provides new pathways for fabricating advanced thermal insulating materials with large scalability and demonstrates great potential for the protection of electronic devices.
基金supported in part by the Hubei Provincial Science and Technology Major Project of China(Grant No.2020AEA011)in part by the National Ethnic Affairs Commission of the People’s Republic of China(Training Program for Young and Middle-aged Talents)(No:MZR20007)+4 种基金in part by the National Natural Science Foundation of China(Grant No.61902437)in part by the Hubei Provincial Natural Science Foundation of China(Grant No.2020CFB629)in part by the Application Foundation Frontier Project of Wuhan Science and Technology Program(Grant No.2020020601012267)in part by the Fundamental Research Funds for the Central Universities,South-Central MinZu University(No:CZQ21026)in part by the Special Project on Regional Collaborative Innovation of Xinjiang Uygur Autonomous Region(Plan to Aid Xinjiang with Science and Technology)(2022E02035)。
文摘The path planning of Unmanned Aerial Vehicle(UAV)is a critical issue in emergency communication and rescue operations,especially in adversarial urban environments.Due to the continuity of the flying space,complex building obstacles,and the aircraft's high dynamics,traditional algorithms cannot find the optimal collision-free flying path between the UAV station and the destination.Accordingly,in this paper,we study the fast UAV path planning problem in a 3D urban environment from a source point to a target point and propose a Three-Step Experience Buffer Deep Deterministic Policy Gradient(TSEB-DDPG)algorithm.We first build the 3D model of a complex urban environment with buildings and project the 3D building surface into many 2D geometric shapes.After transformation,we propose the Hierarchical Learning Particle Swarm Optimization(HL-PSO)to obtain the empirical path.Then,to ensure the accuracy of the obtained paths,the empirical path,the collision information and fast transition information are stored in the three experience buffers of the TSEB-DDPG algorithm as dynamic guidance information.The sampling ratio of each buffer is dynamically adapted to the training stages.Moreover,we designed a reward mechanism to improve the convergence speed of the DDPG algorithm for UAV path planning.The proposed TSEB-DDPG algorithm has also been compared to three widely used competitors experimentally,and the results show that the TSEB-DDPG algorithm can archive the fastest convergence speed and the highest accuracy.We also conduct experiments in real scenarios and compare the real path planning obtained by the HL-PSO algorithm,DDPG algorithm,and TSEB-DDPG algorithm.The results show that the TSEBDDPG algorithm can archive almost the best in terms of accuracy,the average time of actual path planning,and the success rate.
文摘In order to secure the massive heterogeneous medical data for the complex scenarios and improve the information sharing efficiency in healthcare system,a distributed medical data ledger model(DMDL)is proposed in this paper.This DMDL model has adopted the blockchain technology including the function decoupling,the distributed consensus,smart contract as well as multi-channel communication structure of consortium blockchain.The DMDL model not only has high adaptability,but also meets the requirements of the medical treatment processes which generally involve multientities,highly private information and secure transaction.The steps for processing the medical data are also introduced.Additionally,the methods for the definition and application of the DMDL model are presented for three specific medical scenarios,i.e.,the management of the heterogeneous data,copyright protection for medical data and the secure utilization of sensitive data.The advantage of the proposed DMDL model is demonstrated by comparing with the models which are being currently adopted in healthcare system.
文摘Architecturat heritage conservation is an important field in architectural research. The Hui-styte vernacutar dwetling is an essentialarchitectural heritage of China. Its hollow watt system, with horsehead-like upper corners, is a distinct architecturat feature that is worth preserving. However, the thermat performance of the hollow watt is relatively poor by today＇s standard. The current study developed a novel approach, whereby foam concrete was used to fill the voids inside the holtow watt to improve its thermat resistance. This approach was deemed cost effective, easy to learn, and capable of preserving the architectural integrity of the watt. Different types of foam concrete were prepared and tested. Testing results showed that the material properties of foam concrete are suitabte for thermaUy upgrading the hollow watt system. Ctimate chamber testing was conducted to investigate the effectiveness of the proposed thermat upgrading strategy. The testing resutts suggested that tilting the voids with foam concrete can effectively improve the overall thermal resistance of the holtow watt system by 24%, which is almost equal to the overall thermal resistance when using the more expensive commercial inorganic stucco system.
基金supported by the National Key Research and Development Program of China(no.2023YFC3009502)the National Natural Science Foundation of China(nos.51890904,52022022,and 52371134)+2 种基金the Natural Science Foundation of Jiangsu Province(no.BK20231432)the Aeronautical Science Foundation of China(no.2023Z015069001)the Fundamental Research Funds for the Central Universities(no.2242023K40027).
文摘Thermo-responsive hydrogels can dynamically modulate incident light,providing a broad prospect for development of smart windows,which are of pivotal importance for energy conservation in buildings.However,these hydrogels normally exhibit slow response speed and tend to contract over extended phase transition,compromising structural integrity of smart windows.In this study,a solid–liquid switchable thermochromic hydrogel,denoted as SL-PNIPAm,was synthesized by cross-linking PNIPAm with AMEO through dynamic imine bonds.Due to its distinctive solid–liquid transformation characteristics,SL-PNIPAm demonstrates rapid response time(within 5 s)and retains structural integrity without undergoing shrinkage during heating/cooling and freezing/thawing cycles.
