Piezoelectric ceramic and polymeric separators have been proposed to effectively regulate Li deposition and suppress dendrite growth,but such separators still fail to satisfactorily support durable operation of lithiu...Piezoelectric ceramic and polymeric separators have been proposed to effectively regulate Li deposition and suppress dendrite growth,but such separators still fail to satisfactorily support durable operation of lithium metal batteries owing to the fragile ceramic layer or low-piezoelectricity polymer as employed.Herein,by combining PVDF-HFP and ferroelectric BaTiO_(3),we develop a homogeneous,single-layer composite separator with strong piezoelectric effects to inhibit dendrite growth while maintaining high mechanical strength.As squeezed by local protrusion,the polarized PVDF-HFP/BaTiO_(3)composite separator generates a local voltage to suppress the local-intensified electric field and further deconcentrate regional lithium-ion flux to retard lithium deposition on the protrusion,hence enabling a smoother and more compact lithium deposition morphology than the unpoled composite separator and the pure PVDF-HFP separator,especially at high rates.Remarkably,the homogeneous incorporation of BaTiO_(3)highly improves the piezoelectric performances of the separator with residual polarization of 0.086 pC cm^(-2)after polarization treatment,four times that of the pure PVDF-HFP separator,and simultaneously increases the transference number of lithium-ion from 0.45 to 0.57.Beneficial from the prominent piezoelectric mechanism,the polarized PVDF-HFP/BaTiO_(3)composite separator enables stable cyclic performances of Li||LiFePO_(4)cells for 400 cycles at 2 C(1 C=170 mA g^(-1))with a capacity retention above 99%,and for 600 cycles at 5 C with a capacity retention over 85%.展开更多
Infrared camouflage based on artificial thermal metasurfaces has recently attracted significant attention.By eliminating thermal radiation differences between the object and the background,it is possible to hide a giv...Infrared camouflage based on artificial thermal metasurfaces has recently attracted significant attention.By eliminating thermal radiation differences between the object and the background,it is possible to hide a given object from infrared detection.Infrared camouflage is an important element that increases the survivability of aircraft and missiles,by reducing target susceptibility to infrared guided threats.Herein,a simple and practicable design is theoretically presented based on a multilayer film for infrared stealth,with distinctive advantages of scalability,flexible fabrication,and structural simplicity.The multilayer medium consists of silicon substrate,carbon layer and zinc sulfide film,the optical properties of which are determined by transfer matrix method.By locally changing the thickness of the coating film,the spatial tunability and continuity in thermal emission are demonstrated.A continuous change of emissive power is further obtained and consequently implemented to achieve thermal camouflage functionality.In addition,other functionalities,like thermal illusion and thermal coding,are demonstrated by thickness-engineered multilayer films.展开更多
This paper proposes a frequency reconfigurable triangular antenna actuated by an inflated triangular structure.The open path antenna is transformed from an open type to a closed structure by inflating.Inflatable struc...This paper proposes a frequency reconfigurable triangular antenna actuated by an inflated triangular structure.The open path antenna is transformed from an open type to a closed structure by inflating.Inflatable structures are easy to manufacture by fusing 2 inextensible membranes together along a defined pattern of lines.However,the prediction of their deployed shape remains a challenge.To solve the pattern changed problem,guided by geometric analyses and local buckle characteristics,the inflated triangular structure has been designed and verified by experiment and simulation.In the process of transformation of the antenna,the resonant frequency of the antenna is changed because this frequency is determined by the conformational change.The resonant frequency changes from GHz to kHz when the design of initial structure sizes is from millimeter to meter.The measured peak gains,the frequency,and the radiation direction are also reconfigurable by the initial size.Finally,the reconfigurable resonator array is presented,which is coupled to electric fields to absorb all incident radiation.In this work,the changed pattern design by inflating is applied to the antenna design,and its frequency reconfigurability is achieved.Through the electricity performance analysis of the reconfigurable antenna,precise manufacturing will be possible and provide guidance for manufacturing frequency reconfigurable antennas.展开更多
Methods of manipulating protein in cells are of great value in research and clinical therapies.Indirect methods,such as plasmid and mRNA transfection,and virus-based delivery,have been important skills of life science...Methods of manipulating protein in cells are of great value in research and clinical therapies.Indirect methods,such as plasmid and mRNA transfection,and virus-based delivery,have been important skills of life science and medical researchers.Although extensively applied,these nucleic-acids-based approaches are limited by many shortcomings[1].It is very difficult to precisely manipulate the expression level and timeframe of the objective protein in host cells in these methods.The intracellular stabilities of the plasmids or mRNAs that encode the objective genes are affected by several factors,including gene sequence,three-dimensional structure,host nucleases and their delivery processes.These indirect methods require the host transcriptional and translational systems for protein synthesis.However,the transcription and translation machines are tightly regulated by host signaling.In addition,the immunogenicity of DNAs and viral vectors,and the safety of the lipid nanoparticles for mRNA transfection are obstacles of these indirect methods in many clinical applications[2].In contrast,direct protein delivery with target-cell specificity is more efficient in controlling the quantity and function of the protein of interest.However,due to the hydrophobicity of plasma membrane and high molecular weights of proteins,it remains a great challenge to direct deliver protein into target cells across the intact plasma membrane.展开更多
A stratospheric airship is an essential flight vehicle in the aviation field.In this paper,optimal design approach of stratospheric airships is developed to optimize envelope shape considering three failure modes and ...A stratospheric airship is an essential flight vehicle in the aviation field.In this paper,optimal design approach of stratospheric airships is developed to optimize envelope shape considering three failure modes and multidisciplinary analysis models,and could also reduce the mass of a stratospheric airship to be deployed at a specific location.Based on a theoretical analysis,three failure modes of airships including bending wrinkling failure,hoop tearing failure and bending kink failure,are given to describe and illustrate the failure mechanism of stratospheric airships.The results show that the location,length and size of the local uniform load and the large fineness ratio are easier to lead to bending wrinkling failure and bending kink failure.The small fineness ratio and the increasing differential pressure are more prone to cause hoop tearing failure for an airship hull.The failure probability is sensitive to the wind field.From an optimization design,the reliability analysis is essential to be carried out based on the safety of the airship.The solution in this study can provide economical design recommendations.展开更多
Owing to the unique advantages in flight altitude,dwelling time and wide coverage area,stratospheric airships provide permanent monitoring and surveillance for both civil and military applications.Here we propose a se...Owing to the unique advantages in flight altitude,dwelling time and wide coverage area,stratospheric airships provide permanent monitoring and surveillance for both civil and military applications.Here we propose a semi-rigid stratosphere airship design with circumferential high-pressure inflatable rings and a longitudinal carbon fiber skeleton supported inside.We perform numerical simulations to analyze the deformation characteristics during the whole ascending and descending process.An equivalent internal gradient pressure model of helium is established based on the capsule shape and buoyancy-weight equilibrium conditions.The implicit dynamic method is used to deal with the large deformation of the airship capsule under a low negative pressure condition.Deformation and load-bearing performance of the airship capsule,inflatable ring,skeleton,and suspension line are obtained under different working conditions.The results show that the airship,supported with the inflatable rings and the suspension lines,effectively maintains the shape and ensures the stiffness during the ascending,dwelling,and descending stages,especially suffering from negative pressure.展开更多
Origami,such as Miura-ori,is the art of folding two-dimensional materials into complex,elaborate,and multifunctional three-dimensional objects.In this paper,SMP MO sheet are prepared,and the accuracy of deployable pro...Origami,such as Miura-ori,is the art of folding two-dimensional materials into complex,elaborate,and multifunctional three-dimensional objects.In this paper,SMP MO sheet are prepared,and the accuracy of deployable process is verified by experiments.The folding and deployable process of SMP MO sheet is divided into 4 stages,and each stage is described in detail.The stiffness of smart deployable stage is characterized by an exponential decline at the beginning and a gradual decrease to 0,and this is similar to the theoretical shear equivalent modulus in the Y direction.The effects of various parameters on strain and stress are also explored.The purpose of studying these mechanical characteristics is to provide driving force reference in application;In terms of application,the flow field and electromagnetic characteristics of MO sheet in different directions are studied.The aerodynamic drag and RCS reduction of MO unit cell and graded MO sheet during the deployable process are evaluated.When the dihedral fold angle is about 45°,the RCS reduction and drag reduction characteristics of MO sheet are relatively optimal,which is most beneficial to morphing aircraft.展开更多
A floating air weapon system(such as airborne floating mines)plays an important role in modern air defense operations.This paper focuses on aeroelastic characteristics of airborne floating mine named inflated pillow.F...A floating air weapon system(such as airborne floating mines)plays an important role in modern air defense operations.This paper focuses on aeroelastic characteristics of airborne floating mine named inflated pillow.Firstly,the dynamic deployable process of the pillow and characteristics of the local instability of the edge are studied,and the evolution mechanism of wrinkles and kinks is analyzed.Secondly,in the cruising stage,the fluid-structural-thermal coupling analysis is performed on the pillow,and the aeroelastic characteristics are studied.Thirdly,the shapepreserving effect of the inflated pillow during the“negative pressure”slow landing stage is evaluated.It is found that when the wind velocity is higher,the pillow has a collapsed instability(surface extrusion and contact),and when the wind velocity is lower,snap-through instability occurs.Finally,for the collapsed instability,a carbon fiber skeleton is added to discrete the large global collapsed fold into small local folds,thus achieving shape-preserving effect of pillow.For snapthrough instability,the critical internal pressure and different shape evolution under different wind velocity are evaluated.Through the analysis of the mechanical mechanism and control of the structural morphological evolution,it provides theoretical guidance for the application of the curved shell structure in floating air weapon system.展开更多
基金supported by the Science Foundation of National Key Laboratory of Science and Technology on Advanced Composites in Special Environmentsthe National Natural Science Foundation of China(12002109)
文摘Piezoelectric ceramic and polymeric separators have been proposed to effectively regulate Li deposition and suppress dendrite growth,but such separators still fail to satisfactorily support durable operation of lithium metal batteries owing to the fragile ceramic layer or low-piezoelectricity polymer as employed.Herein,by combining PVDF-HFP and ferroelectric BaTiO_(3),we develop a homogeneous,single-layer composite separator with strong piezoelectric effects to inhibit dendrite growth while maintaining high mechanical strength.As squeezed by local protrusion,the polarized PVDF-HFP/BaTiO_(3)composite separator generates a local voltage to suppress the local-intensified electric field and further deconcentrate regional lithium-ion flux to retard lithium deposition on the protrusion,hence enabling a smoother and more compact lithium deposition morphology than the unpoled composite separator and the pure PVDF-HFP separator,especially at high rates.Remarkably,the homogeneous incorporation of BaTiO_(3)highly improves the piezoelectric performances of the separator with residual polarization of 0.086 pC cm^(-2)after polarization treatment,four times that of the pure PVDF-HFP separator,and simultaneously increases the transference number of lithium-ion from 0.45 to 0.57.Beneficial from the prominent piezoelectric mechanism,the polarized PVDF-HFP/BaTiO_(3)composite separator enables stable cyclic performances of Li||LiFePO_(4)cells for 400 cycles at 2 C(1 C=170 mA g^(-1))with a capacity retention above 99%,and for 600 cycles at 5 C with a capacity retention over 85%.
基金support by the China Scholarship Council(CSC).This research has additionally been funded by the Deutsche Forschungsgemeinschaft(DFG,German Research Foundation)under Germany’s Excellence Strategy via the Excellence Cluster“3D Matter Made to Order”(Grant No.EXC-2082/1-390761711)which has also been supported by the Carl Zeiss Foundation through the“Carl-Zeiss-Foundation-Focus@HEiKA”,by the State of Baden-Württemberg,and by the Karlsruhe Institute of Technology(KIT).We further acknowledge support by the Helmholtz program“Materials Systems Engineering”(MSE).Muamer Kadic is grateful for support by the EIPHI Graduate School(Grant No.ANR-17-EURE-0002)Changguo Wang is grateful for support by the National Natural Science Foundation of China(Grant No.12172102).
基金supported by the EIPHI Graduate School(No.ANR-17-EURE-0002)the French Investissements d’Avenir program,project ISITEBFC(No.ANR-15-IDEX-03)+1 种基金the National Natural Science Foundation of China(Nos.12172102,11872160 and 11732002)the support of the Alexander von Humboldt Foundation through the Feodor Lynen Fellowship。
文摘Infrared camouflage based on artificial thermal metasurfaces has recently attracted significant attention.By eliminating thermal radiation differences between the object and the background,it is possible to hide a given object from infrared detection.Infrared camouflage is an important element that increases the survivability of aircraft and missiles,by reducing target susceptibility to infrared guided threats.Herein,a simple and practicable design is theoretically presented based on a multilayer film for infrared stealth,with distinctive advantages of scalability,flexible fabrication,and structural simplicity.The multilayer medium consists of silicon substrate,carbon layer and zinc sulfide film,the optical properties of which are determined by transfer matrix method.By locally changing the thickness of the coating film,the spatial tunability and continuity in thermal emission are demonstrated.A continuous change of emissive power is further obtained and consequently implemented to achieve thermal camouflage functionality.In addition,other functionalities,like thermal illusion and thermal coding,are demonstrated by thickness-engineered multilayer films.
基金supported by the National Natural Science Foundation of China(No.12172102).
文摘This paper proposes a frequency reconfigurable triangular antenna actuated by an inflated triangular structure.The open path antenna is transformed from an open type to a closed structure by inflating.Inflatable structures are easy to manufacture by fusing 2 inextensible membranes together along a defined pattern of lines.However,the prediction of their deployed shape remains a challenge.To solve the pattern changed problem,guided by geometric analyses and local buckle characteristics,the inflated triangular structure has been designed and verified by experiment and simulation.In the process of transformation of the antenna,the resonant frequency of the antenna is changed because this frequency is determined by the conformational change.The resonant frequency changes from GHz to kHz when the design of initial structure sizes is from millimeter to meter.The measured peak gains,the frequency,and the radiation direction are also reconfigurable by the initial size.Finally,the reconfigurable resonator array is presented,which is coupled to electric fields to absorb all incident radiation.In this work,the changed pattern design by inflating is applied to the antenna design,and its frequency reconfigurability is achieved.Through the electricity performance analysis of the reconfigurable antenna,precise manufacturing will be possible and provide guidance for manufacturing frequency reconfigurable antennas.
基金the National Natural Science Foundation of China(81925024)the Fundamental Research Funds for the Central Universities。
文摘Methods of manipulating protein in cells are of great value in research and clinical therapies.Indirect methods,such as plasmid and mRNA transfection,and virus-based delivery,have been important skills of life science and medical researchers.Although extensively applied,these nucleic-acids-based approaches are limited by many shortcomings[1].It is very difficult to precisely manipulate the expression level and timeframe of the objective protein in host cells in these methods.The intracellular stabilities of the plasmids or mRNAs that encode the objective genes are affected by several factors,including gene sequence,three-dimensional structure,host nucleases and their delivery processes.These indirect methods require the host transcriptional and translational systems for protein synthesis.However,the transcription and translation machines are tightly regulated by host signaling.In addition,the immunogenicity of DNAs and viral vectors,and the safety of the lipid nanoparticles for mRNA transfection are obstacles of these indirect methods in many clinical applications[2].In contrast,direct protein delivery with target-cell specificity is more efficient in controlling the quantity and function of the protein of interest.However,due to the hydrophobicity of plasma membrane and high molecular weights of proteins,it remains a great challenge to direct deliver protein into target cells across the intact plasma membrane.
基金financial support from the National Natural Science Foundation of China(Nos.11872160 and 11572099)。
文摘A stratospheric airship is an essential flight vehicle in the aviation field.In this paper,optimal design approach of stratospheric airships is developed to optimize envelope shape considering three failure modes and multidisciplinary analysis models,and could also reduce the mass of a stratospheric airship to be deployed at a specific location.Based on a theoretical analysis,three failure modes of airships including bending wrinkling failure,hoop tearing failure and bending kink failure,are given to describe and illustrate the failure mechanism of stratospheric airships.The results show that the location,length and size of the local uniform load and the large fineness ratio are easier to lead to bending wrinkling failure and bending kink failure.The small fineness ratio and the increasing differential pressure are more prone to cause hoop tearing failure for an airship hull.The failure probability is sensitive to the wind field.From an optimization design,the reliability analysis is essential to be carried out based on the safety of the airship.The solution in this study can provide economical design recommendations.
基金support from the National Natural Science Foundation of China(No.11872160).
文摘Owing to the unique advantages in flight altitude,dwelling time and wide coverage area,stratospheric airships provide permanent monitoring and surveillance for both civil and military applications.Here we propose a semi-rigid stratosphere airship design with circumferential high-pressure inflatable rings and a longitudinal carbon fiber skeleton supported inside.We perform numerical simulations to analyze the deformation characteristics during the whole ascending and descending process.An equivalent internal gradient pressure model of helium is established based on the capsule shape and buoyancy-weight equilibrium conditions.The implicit dynamic method is used to deal with the large deformation of the airship capsule under a low negative pressure condition.Deformation and load-bearing performance of the airship capsule,inflatable ring,skeleton,and suspension line are obtained under different working conditions.The results show that the airship,supported with the inflatable rings and the suspension lines,effectively maintains the shape and ensures the stiffness during the ascending,dwelling,and descending stages,especially suffering from negative pressure.
基金the financial support from the National Natural Science Foundation of China(No.11872160)the Science Foundation of the National Key Laboratory of Science and Technology on Advanced Composites in Special Environments(JCKYS2020603C007)。
文摘Origami,such as Miura-ori,is the art of folding two-dimensional materials into complex,elaborate,and multifunctional three-dimensional objects.In this paper,SMP MO sheet are prepared,and the accuracy of deployable process is verified by experiments.The folding and deployable process of SMP MO sheet is divided into 4 stages,and each stage is described in detail.The stiffness of smart deployable stage is characterized by an exponential decline at the beginning and a gradual decrease to 0,and this is similar to the theoretical shear equivalent modulus in the Y direction.The effects of various parameters on strain and stress are also explored.The purpose of studying these mechanical characteristics is to provide driving force reference in application;In terms of application,the flow field and electromagnetic characteristics of MO sheet in different directions are studied.The aerodynamic drag and RCS reduction of MO unit cell and graded MO sheet during the deployable process are evaluated.When the dihedral fold angle is about 45°,the RCS reduction and drag reduction characteristics of MO sheet are relatively optimal,which is most beneficial to morphing aircraft.
基金the financial support from the National Natural Science Foundation of China(11872160)the Science Foundation of National Key Laboratory of Science and Technology on Advanced Composites in Special Environments,China(JCKYS2020603C007)。
文摘A floating air weapon system(such as airborne floating mines)plays an important role in modern air defense operations.This paper focuses on aeroelastic characteristics of airborne floating mine named inflated pillow.Firstly,the dynamic deployable process of the pillow and characteristics of the local instability of the edge are studied,and the evolution mechanism of wrinkles and kinks is analyzed.Secondly,in the cruising stage,the fluid-structural-thermal coupling analysis is performed on the pillow,and the aeroelastic characteristics are studied.Thirdly,the shapepreserving effect of the inflated pillow during the“negative pressure”slow landing stage is evaluated.It is found that when the wind velocity is higher,the pillow has a collapsed instability(surface extrusion and contact),and when the wind velocity is lower,snap-through instability occurs.Finally,for the collapsed instability,a carbon fiber skeleton is added to discrete the large global collapsed fold into small local folds,thus achieving shape-preserving effect of pillow.For snapthrough instability,the critical internal pressure and different shape evolution under different wind velocity are evaluated.Through the analysis of the mechanical mechanism and control of the structural morphological evolution,it provides theoretical guidance for the application of the curved shell structure in floating air weapon system.