Artificial architected metamaterials equipped with unique mechanical and physical properties that are naturally inaccessible can be obtained by rational design.In this work,the innovative three-dimensional(3D)chiral a...Artificial architected metamaterials equipped with unique mechanical and physical properties that are naturally inaccessible can be obtained by rational design.In this work,the innovative three-dimensional(3D)chiral and anti-chiral metamaterials are developed referring to the face-rotating polyhedral(FRP)structure present in the virus.Through assembling planar triangular units into the regular octahedron cells,several typical forms of chiral and anti-chiral metamaterials can be obtained by different assembly methods.By changing the topology parameters,the Poisson’s ratio can be adjusted between[0,2.8].The metamaterials are fabricated by 3D printing utilizing shape memory polymer,and the mechanical properties are analyzed via Finite Element Analysis(FEA)and experiments,including Young’s modulus,Poisson’s ratio,and tension-twist coupling behavior.In addition,target metamaterial with specific local deformation behavior is obtained by programmatic calculations and distributions to meet special requirements or achieve unique applications.The shape memory property endows the mechanical metamaterials with more potential applications.展开更多
Artificial metamaterials have attracted widespread attention of research communities due to their anomalous physical properties compared to those of conventional materials.In this study,we designed a three-dimensiona...Artificial metamaterials have attracted widespread attention of research communities due to their anomalous physical properties compared to those of conventional materials.In this study,we designed a three-dimensional(3D)lightweight metaarchitecture consisting of 6-connected anti-chiral honeycombs.The mechanical properties(e.g.Young’s modulus,compression strength,and Poisson’s ratio)of the proposed meta-architecture could be programmed by adjusting a series of geometric parameters,as shown through numerical simulations.Moreover,an optically sensitive polymer-based 3D meta-architecture with 6-connected anti-chiral features was constructed by the stereolithography method.Owing to the regulation of the negative Poisson’s ratio,3D meta-architecture achieved a greater ductility under compression than those of traditional truss structures while retaining a relatively high strength and low density.Compression experiments validated the excellent tunability of the mechanical properties of the proposed 3D 6-connected antichiral structure.The results suggest the promising applications of this structure in lightweight aircraft,vibration isolation,and mechanical sensors.展开更多
We revisit the novel symmetries in N=2 supersymmetric quantum mechanical models by considering specific examples of coupled systems.Further,we extend our analysis to a general case and list out all the novel symmetrie...We revisit the novel symmetries in N=2 supersymmetric quantum mechanical models by considering specific examples of coupled systems.Further,we extend our analysis to a general case and list out all the novel symmetries.In each case,we show the existence of two sets of discrete symmetries that correspond to the Hodge duality operator of differential geometry.Thus,we are able to provide a proof of the conjecture which points out the existence of more than one set of discrete symmetry transformations corresponding to the Hodge duality operator.Moreover,we derive on-shell nilpotent symmetries for a generalized superpotential within the framework of supervariable approach.展开更多
基金the National Natural Science Foundation of China[Grant No.12072094 and 12172106]Heilongjiang Touyan Innovation Team Program and the Fundamental Research Funds for the Central Universities[No.IR2021106 and IR2021232]。
文摘Artificial architected metamaterials equipped with unique mechanical and physical properties that are naturally inaccessible can be obtained by rational design.In this work,the innovative three-dimensional(3D)chiral and anti-chiral metamaterials are developed referring to the face-rotating polyhedral(FRP)structure present in the virus.Through assembling planar triangular units into the regular octahedron cells,several typical forms of chiral and anti-chiral metamaterials can be obtained by different assembly methods.By changing the topology parameters,the Poisson’s ratio can be adjusted between[0,2.8].The metamaterials are fabricated by 3D printing utilizing shape memory polymer,and the mechanical properties are analyzed via Finite Element Analysis(FEA)and experiments,including Young’s modulus,Poisson’s ratio,and tension-twist coupling behavior.In addition,target metamaterial with specific local deformation behavior is obtained by programmatic calculations and distributions to meet special requirements or achieve unique applications.The shape memory property endows the mechanical metamaterials with more potential applications.
基金financially supported by the National Natural Science Foundation of China(Grant No.52073132),Science Fund for Distinguished Young Scholars of Gansu Province(Grant No.18JR3RA263),the Fundamental Research Funds for the Central Universities(Grant No.lzujbky-2020-ct05),the Talent Innovation and Entrepreneurship Project of Lanzhou(Grant No:2019-RC-42),and the 2019 Civil-Military Integration Project of Lanzhou(Grant No:GF-2019-ZA-QT-05)。
文摘Artificial metamaterials have attracted widespread attention of research communities due to their anomalous physical properties compared to those of conventional materials.In this study,we designed a three-dimensional(3D)lightweight metaarchitecture consisting of 6-connected anti-chiral honeycombs.The mechanical properties(e.g.Young’s modulus,compression strength,and Poisson’s ratio)of the proposed meta-architecture could be programmed by adjusting a series of geometric parameters,as shown through numerical simulations.Moreover,an optically sensitive polymer-based 3D meta-architecture with 6-connected anti-chiral features was constructed by the stereolithography method.Owing to the regulation of the negative Poisson’s ratio,3D meta-architecture achieved a greater ductility under compression than those of traditional truss structures while retaining a relatively high strength and low density.Compression experiments validated the excellent tunability of the mechanical properties of the proposed 3D 6-connected antichiral structure.The results suggest the promising applications of this structure in lightweight aircraft,vibration isolation,and mechanical sensors.
基金support from the FRG scheme of National Institute of Technology Calicut。
文摘We revisit the novel symmetries in N=2 supersymmetric quantum mechanical models by considering specific examples of coupled systems.Further,we extend our analysis to a general case and list out all the novel symmetries.In each case,we show the existence of two sets of discrete symmetries that correspond to the Hodge duality operator of differential geometry.Thus,we are able to provide a proof of the conjecture which points out the existence of more than one set of discrete symmetry transformations corresponding to the Hodge duality operator.Moreover,we derive on-shell nilpotent symmetries for a generalized superpotential within the framework of supervariable approach.
