This paper presents the solutions and results of the 12th edition of the Global Trajectory Optimization Competition (GTOC12) of the National University of Defense and Technology. To address the complex interstellar mi...This paper presents the solutions and results of the 12th edition of the Global Trajectory Optimization Competition (GTOC12) of the National University of Defense and Technology. To address the complex interstellar mining problem proposed by GTOC12, our solution is divided into two stages. The first stage focuses on preliminary work, including the target selection, the establishment of departure and return databases, and the development of methods to estimate transfer costs, with the aim of enhancing planning efficiency during the global planning phase. The second stage involves trajectory optimization for multiple mining ships, including single-mining-ship trajectory optimization and a multiship iterative process. For single-mining-ship trajectory optimization, the method involves three steps: first, employ a heuristic method for planning the first rendezvous sequences;second, utilize an ant colony optimization (ACO) algorithm for planning the second rendezvous sequences;and third, apply a differential evolution (DE) algorithm alongside an indirect method to refine rendezvous times and low-thrust trajectories. Through the implementation of a multiship iterative strategy, the team accomplished trajectory optimization for multiple mining ships that met the constraints. The final score submitted by the team was 15,160.946, which achieved the sixth place in the competition.展开更多
The safety issues of lithium-ion batteries have received attention because flammable organic electrolytes are used.Also,the commercial polyolefin separator will undergo severe thermal shrinkage when the internal tempe...The safety issues of lithium-ion batteries have received attention because flammable organic electrolytes are used.Also,the commercial polyolefin separator will undergo severe thermal shrinkage when the internal temperature of the battery increases to 130-160°C,which increases the risk.Therefore,the development of a high thermal stability and high-safety separator is an effective strategy to improve battery safety.Herein,we design a green,cellulose-based separator(Cel@DBDPE)with a unique encapsulation structure for lithium-ion batteries,in which functional flame retardants(DBDPE)are wrapped in microscrolls formed by the self-rolling of 2D cellulose nanosheets upon freeze-drying.This structure can firmly anchor DBDPE particles in the separator to prevent them from undergoing exfoliation and does not affect the properties of the separator,such as the thickness and the pore structure.Compared with commercial polypropylene,Cel@DBDPE has excellent thermal stability and flame retardancy.The former makes it less prone to thermal shrinkage and the latter can effectively prevent the combustion of the electrolyte,showing an efficient self-extinguishing ability.Moreover,the Cel@DBDPE is only 15μm in size and has competitive properties comparable to polypropylene.Thus,there is no sacrifice in the electrochemical performance of battery when the Cel@DBDPE is used as separator.This study provides a new structural design for the construction of a high-safety separator.展开更多
Human pluripotent stem cells provide an inexhaustible model to study human embryogenesis in vitro.Recent studies have provided diverse models to generate human blastoids by self-organization of different pluripotent s...Human pluripotent stem cells provide an inexhaustible model to study human embryogenesis in vitro.Recent studies have provided diverse models to generate human blastoids by self-organization of different pluripotent stem cells or somatic reprogramming intermediates.However,whether blastoids can be generated from other cell types or whether they can recapitulate postimplantation development in vitro is unknown.Here,we develop a strategy to generate human blastoids from heterogeneous intermediates with epiblast,trophectoderm,and primitive endoderm signatures of the primed-to-naïve conversion process,which resemble natural blastocysts in morphological architecture,composition of cell lineages,transcriptome,and lineage differentiation potential.In addition,these blastoids reflect many features of human peri-implantation and pregastrulation development when further cultured in an in vitro 3D culture system.In summary,our study provides an alternative strategy to generate human blastoids and offers insights into human early embryogenesis by modeling peri-and postimplantation development in vitro.展开更多
Power sources with strong mechanical properties and high-energy density are highly desirable for the next-generation flexible electronics.However,the challenge arises from the current electrode structure design,which ...Power sources with strong mechanical properties and high-energy density are highly desirable for the next-generation flexible electronics.However,the challenge arises from the current electrode structure design,which is unable to bring both satisfactory mechanical and electrochemical properties with high active materials content and mass.Herein,we reported novel flexible,highstrength,and mechanically stable TiO_(2)-based film electrodes for advanced sodium-ion batteries,achieving an ultrahigh strength(up to≈60 MPa)and commercial-level areal capacity(4.5 mAh cm^(-2)).Highly-dispersed TiO_(2) and interlaced carbon nanotube(CNT)networks are embedded in the sheet-liked cellulose to form porous,high-conductive,and high-active TiO_(2)-C nanosheets that is basic building subunits of TiO_(2)-C films,allowing the films with structural robustness and origami-level flexibility.This strategy reconciles the contradiction between mechanical properties and active material content in flexible electrodes,and the fabricated electrode with a high TiO_(2) content of>65%can be bent more than 11000 times without breaking.Meanwhile,good capacity and excellent cycle stability(0.02‰capacity-decay rate over 9000 cycles)of TiO_(2)-C film under a higher active content(75%)has well satisfied the demands of flexible energy storage devices for electrochemical performances.This TiO_(2)-C subunit assembly methodology demonstrates enormous potential in high-strength/toughness flexible electrode construction for flexible electronics.展开更多
文摘This paper presents the solutions and results of the 12th edition of the Global Trajectory Optimization Competition (GTOC12) of the National University of Defense and Technology. To address the complex interstellar mining problem proposed by GTOC12, our solution is divided into two stages. The first stage focuses on preliminary work, including the target selection, the establishment of departure and return databases, and the development of methods to estimate transfer costs, with the aim of enhancing planning efficiency during the global planning phase. The second stage involves trajectory optimization for multiple mining ships, including single-mining-ship trajectory optimization and a multiship iterative process. For single-mining-ship trajectory optimization, the method involves three steps: first, employ a heuristic method for planning the first rendezvous sequences;second, utilize an ant colony optimization (ACO) algorithm for planning the second rendezvous sequences;and third, apply a differential evolution (DE) algorithm alongside an indirect method to refine rendezvous times and low-thrust trajectories. Through the implementation of a multiship iterative strategy, the team accomplished trajectory optimization for multiple mining ships that met the constraints. The final score submitted by the team was 15,160.946, which achieved the sixth place in the competition.
基金supported by the National Natural Science Foundation of China(Nos.U22A20140,52072138)the National Key Research and Development Program of China(No.2018YFE0206900).
文摘The safety issues of lithium-ion batteries have received attention because flammable organic electrolytes are used.Also,the commercial polyolefin separator will undergo severe thermal shrinkage when the internal temperature of the battery increases to 130-160°C,which increases the risk.Therefore,the development of a high thermal stability and high-safety separator is an effective strategy to improve battery safety.Herein,we design a green,cellulose-based separator(Cel@DBDPE)with a unique encapsulation structure for lithium-ion batteries,in which functional flame retardants(DBDPE)are wrapped in microscrolls formed by the self-rolling of 2D cellulose nanosheets upon freeze-drying.This structure can firmly anchor DBDPE particles in the separator to prevent them from undergoing exfoliation and does not affect the properties of the separator,such as the thickness and the pore structure.Compared with commercial polypropylene,Cel@DBDPE has excellent thermal stability and flame retardancy.The former makes it less prone to thermal shrinkage and the latter can effectively prevent the combustion of the electrolyte,showing an efficient self-extinguishing ability.Moreover,the Cel@DBDPE is only 15μm in size and has competitive properties comparable to polypropylene.Thus,there is no sacrifice in the electrochemical performance of battery when the Cel@DBDPE is used as separator.This study provides a new structural design for the construction of a high-safety separator.
基金the Ministry of Science and Technology of China(Nos.2021YFA1102000,2021YFC2700300,2019YFA0110000,and 2018YFA0108900)the National Natural Science Foundation of China(NSFC)(Nos.31721003,32022024,32270850,32100633,31871486,32070652,and 81630035)the Science and Technology Commission of Shanghai Municipality(Nos.19JC1415300 and 21JC1405500).
文摘Human pluripotent stem cells provide an inexhaustible model to study human embryogenesis in vitro.Recent studies have provided diverse models to generate human blastoids by self-organization of different pluripotent stem cells or somatic reprogramming intermediates.However,whether blastoids can be generated from other cell types or whether they can recapitulate postimplantation development in vitro is unknown.Here,we develop a strategy to generate human blastoids from heterogeneous intermediates with epiblast,trophectoderm,and primitive endoderm signatures of the primed-to-naïve conversion process,which resemble natural blastocysts in morphological architecture,composition of cell lineages,transcriptome,and lineage differentiation potential.In addition,these blastoids reflect many features of human peri-implantation and pregastrulation development when further cultured in an in vitro 3D culture system.In summary,our study provides an alternative strategy to generate human blastoids and offers insights into human early embryogenesis by modeling peri-and postimplantation development in vitro.
基金Cultivating Excellent Doctoral Dissertation of Forestry Engineering,Grant/Award Number:LYGCYB20202014National Key Research and Development Program of China,Grant/Award Number:2018YFE0206900National Natural Science Foundation of China,Grant/Award Number:51772115。
文摘Power sources with strong mechanical properties and high-energy density are highly desirable for the next-generation flexible electronics.However,the challenge arises from the current electrode structure design,which is unable to bring both satisfactory mechanical and electrochemical properties with high active materials content and mass.Herein,we reported novel flexible,highstrength,and mechanically stable TiO_(2)-based film electrodes for advanced sodium-ion batteries,achieving an ultrahigh strength(up to≈60 MPa)and commercial-level areal capacity(4.5 mAh cm^(-2)).Highly-dispersed TiO_(2) and interlaced carbon nanotube(CNT)networks are embedded in the sheet-liked cellulose to form porous,high-conductive,and high-active TiO_(2)-C nanosheets that is basic building subunits of TiO_(2)-C films,allowing the films with structural robustness and origami-level flexibility.This strategy reconciles the contradiction between mechanical properties and active material content in flexible electrodes,and the fabricated electrode with a high TiO_(2) content of>65%can be bent more than 11000 times without breaking.Meanwhile,good capacity and excellent cycle stability(0.02‰capacity-decay rate over 9000 cycles)of TiO_(2)-C film under a higher active content(75%)has well satisfied the demands of flexible energy storage devices for electrochemical performances.This TiO_(2)-C subunit assembly methodology demonstrates enormous potential in high-strength/toughness flexible electrode construction for flexible electronics.
基金supported by the National Natural Science Foundation of China(U22A20140,52072138)Shenzhen Science and Technology Program(JCYJ20220818100418040 and JCYJ20220530160816038)。
