Smoothly attaching the stretchable epidermal electronic devices(EEDs) onto the skin surface is highly desired to improve the measurement accuracy of electrophysiological signal.The paper presents an analytical approac...Smoothly attaching the stretchable epidermal electronic devices(EEDs) onto the skin surface is highly desired to improve the measurement accuracy of electrophysiological signal.The paper presents an analytical approach to study interfacial mechanics of the 2D planar EEDs on the checkerboard buckling patterns of human skin.Energy variation method is proposed to determine a criterion whether EEDs laminate conformally onto the skin surface under undeformed and stretched cases.EEDs with low bending stiffness(thin,soft devices/backing layer),smooth and soft skin,and strong adhesion promote conformal contact.Furthermore,the adhesion energy at the EED/skin interface is measured by the homemade peeling experiment platform with different substrate thicknesses and areal coverages.The upper limit of the areal coverage for EED conformal contact with the skin is proposed with given EED/skin properties.Conformability of EEDs are validated by experiments with different substrate thickness,areal coverage and external loadings.It provides a design guideline for EED to conformally contact with the skin surface for more accurate biological signal monitoring.展开更多
Peptide-based assemblies have gained increasing attention in different areas of nanotechnology,drug delivery and molecular biology.Among these,non-natural β-peptide scaffolds are particularly promising,as their progr...Peptide-based assemblies have gained increasing attention in different areas of nanotechnology,drug delivery and molecular biology.Among these,non-natural β-peptide scaffolds are particularly promising,as their programmable and diverse secondary structures,high metabolic stability and strong self-association propensity can be easily exploited to create variable constructs.We have recently demonstrated that heterochiral,acyclic β^(3)-peptides assembled into striped lamellar nanostructures that induced antibacterial activity.The process of this assembly formation could be exploited in diverse areas,however identifying oligomerisation stages,and more importantly,controlling the spontaneous process at different levels is still lacking.In this study,a set of analogues heterochiral hexameric β^(3)-peptide sequences was investigated to understand how systematic,small variations of the sequences,such as single point mutation or N-terminal chemical modification,can influence the resulting assemblies and allow the control of formed morphologies.TEM and cryo-EM combined with molecular dynamics simulation enabled the identification and differentiation of morphological stages throughout the entire multi-step process.Depending on the position of the sequence modifications,the self-assembled structures formed small oligomers,individual protofibrils,extended,flat lamellae,bundles and macroscopic clusters.These results outline how the self-assembly process of short heterochiral β-peptides can be qualitatively fine-tuned by sequence modifications,which contribute to understanding the general peptide assembly processes for their fibrillar morphologies.展开更多
Audio-visual speech recognition(AVSR),which integrates audio and visual modalities to improve recognition performance and robustness in noisy or adverse acoustic conditions,has attracted significant research interest....Audio-visual speech recognition(AVSR),which integrates audio and visual modalities to improve recognition performance and robustness in noisy or adverse acoustic conditions,has attracted significant research interest.However,Conformer-based architectures remain computational expensive due to the quadratic increase in the spatial and temporal complexity of their softmax-based attention mechanisms with sequence length.In addition,Conformerbased architectures may not provide sufficient flexibility for modeling local dependencies at different granularities.To mitigate these limitations,this study introduces a novel AVSR framework based on a ReLU-based Sparse and Grouped Conformer(RSG-Conformer)architecture.Specifically,we propose a Global-enhanced Sparse Attention(GSA)module incorporating an efficient context restoration block to recover lost contextual cues.Concurrently,a Grouped-scale Convolution(GSC)module replaces the standard Conformer convolution module,providing adaptive local modeling across varying temporal resolutions.Furthermore,we integrate a Refined Intermediate Contextual CTC(RIC-CTC)supervision strategy.This approach applies progressively increasing loss weights combined with convolution-based context aggregation,thereby further relaxing the constraint of conditional independence inherent in standard CTC frameworks.Evaluations on the LRS2 and LRS3 benchmark validate the efficacy of our approach,with word error rates(WERs)reduced to 1.8%and 1.5%,respectively.These results further demonstrate and validate its state-of-the-art performance in AVSR tasks.展开更多
Control over charge transport in molecular–scale devices requires a deep understanding of how minute structural changes influence electronic properties.Here,we demonstrate dual transport regimes in tunnel junctions o...Control over charge transport in molecular–scale devices requires a deep understanding of how minute structural changes influence electronic properties.Here,we demonstrate dual transport regimes in tunnel junctions of n-alk-1-yne(CnA)molecules with gold electrodes driven by conformational bifurcation—the emergence of two nearly isoenergetic(planar and skewed)molecular conformers(dihedral anglesα=180°andα≈65°at the alkyne terminus in the gas phase).Although the energy differences are small,these subtle conformational differences manifest as distinct transport behaviors,uncovered through unsupervised machine learning,which identified two junction groups:“short”and“long”chains,with distinct attenuation factors(β_(short)≈1.0 vs.β_(long)≈0.74)and contact conductances(G_(c,short)≈200μS vs.G_(c,long)≈8μS).This dramatic impact of the dihedral angle exceeds the impact of the inter-ring twist angle in biphenyl-based junctions and rivals changes induced by switching from gold to platinum electrodes or from monothiol to dithiol anchors in oligoacene and oligophenylene junctions.X-ray photoelectron spectroscopy(XPS)confirmed this bifurcation,linking the“short”and“long”groups to planar and skewed conformers,with dihedrals remarkably agreeing with the gas-phase values.This work establishes conformational bifurcation as a promising route for designing programmable nanotransport properties through anchor-group control.展开更多
Conformational entropy,one of the central concepts of polymer physics,is the key to revealing physical characteristics of polymers.Despite an increased repertoire of conformational-entropy effects in the structural fo...Conformational entropy,one of the central concepts of polymer physics,is the key to revealing physical characteristics of polymers.Despite an increased repertoire of conformational-entropy effects in the structural formation,transition,and properties of polymer systems,the physical origin of conformational entropy remains less understood compared to interaction energy and other types of entropy.This review seeks to provide a conceptual framework unveiling several principles and rules of conformational entropy in governing the structures and properties of polymers,from the perspective of fundamental physics and statistical mechanics.First,we focus on the fundamentals of entropy in thermodynamics,leading to the theoretical basis for the elucidation of conformational entropy.Second,we delineate the physical nature of statistics and dissipation of conformational entropy and its essential dependence on the environmental heat bath.Next,we explore the principles of conformational entropy in driving the ordering transitions of various systems of polymers and their nanocomposites,elucidating the emergent and collective behaviors as well as the interplay between energetic interactions and entropy.Moreover,we demonstrate how the concept of conformational entropy is generalized to the biological systems and other soft matters.Finally,we discuss future directions to signify this framework originated from polymers.展开更多
In contrast to cyclic polymers with ring-like backbones,side-chain cyclization is another intriguing structural feature that has not been extensively studied.In this study,a library of orthogonally protected monomers ...In contrast to cyclic polymers with ring-like backbones,side-chain cyclization is another intriguing structural feature that has not been extensively studied.In this study,a library of orthogonally protected monomers featuring monocyclic,dicyclic,or tricyclic pendant motifs was designed and prepared based on malic acid derivatives.Polyesters with precise chemical structures and uniform chain lengths were prepared modularly through iterative growth.Meticulous control over the chemical details allows for a close investigation of the topological effects on the polymer properties.Compared to their linear side chain counterparts,the presence of cyclic pendant groups has a significant impact on chain conformation,leading to a reduction in hydrodynamic volume and an enhancement in the glass transition temperature.These results underscore the potential of tailoring polymer properties through rational engineering of side chain topology.展开更多
Conformal truss-like lattice structures face significant manufacturability challenges in additive manufac-turing due to overhang angle limitations.To address this problem,we propose a novel angle-constrained optimizat...Conformal truss-like lattice structures face significant manufacturability challenges in additive manufac-turing due to overhang angle limitations.To address this problem,we propose a novel angle-constrained optimization method grounded in the global adjustment of nodal coordinates.First,a build direction is selected to minimize the number of violating struts.Then,an angular-constraint matrix is assembled from strut direction vectors,and analytical sensitivities with respect to nodal coordinates are derived to enable efficient constrained optimization under nonlinear angular inequality constraints.Numerical studies on two complex curved-surface lattices demonstrate that all overhang violations are eliminated while only minor changes are induced in global stiffness and strength.In particular,the maximum displacement of an ergonomic insole varies by only 2.87%after optimization.The results confirm the method’s versatility and engineering robustness,providing a practical approach for additive manufacturing-oriented lattice structure design.展开更多
It is well known that critical points of the total scalar curvature functional S on the space of all smooth Riemannian structures of volume 1 on a compact manifold M are exactly the Einstein metrics.When the domain of...It is well known that critical points of the total scalar curvature functional S on the space of all smooth Riemannian structures of volume 1 on a compact manifold M are exactly the Einstein metrics.When the domain of S is restricted to the space of constant scalar curvature metrics,there has been a conjecture that a critical point is also Einstein or isometric to a standard sphere.In the Riemannian case,it’s tangent space satisfies a decomposition.In this paper,we prove that if we only consider the Hermitian metrics,it also have a decomposition.Then we obtain the equation of the critical points among the Hermitian metrics.展开更多
In this paper,we derive the sub-Riemannian version of the Kastler-Kalau-Walze type theorem and the Dabrowski-Sitarz-Zalecki type theorem for the twisted BCV spaces.We also compute the Connes conformal invariants for t...In this paper,we derive the sub-Riemannian version of the Kastler-Kalau-Walze type theorem and the Dabrowski-Sitarz-Zalecki type theorem for the twisted BCV spaces.We also compute the Connes conformal invariants for the twisted product,as well as the sub-Riemannian limits of the Connes conformal invariants for the twisted BCV spaces.展开更多
In this study,the design,analysis,manufacturing,and testing of a 3D-printed conformal microstrip array antenna for high-temperature environments is presented.3D printing technology is used to fabricate a curved cerami...In this study,the design,analysis,manufacturing,and testing of a 3D-printed conformal microstrip array antenna for high-temperature environments is presented.3D printing technology is used to fabricate a curved ceramic substrate,and laser sintering and microdroplet spraying processes are used to add the conductive metal on the curved substrate.The problems of gain loss,bandwidth reduction,and frequency shift caused by high temperatures are addressed by using a proper antenna design,with parasitic patches,slots,and metal resonant cavities.The antenna prototype is characterized by the curved substrates and the conductive metals for the power dividers,the patch,and the ground plane;its performance is examined up to a temperature of 600℃in a muffle furnace and compared with the results from the numerical analysis.The results show that the antenna can effectively function at 600℃and even higher temperatures.展开更多
The original online version of this article was revised:The layout update for Article 758 has impacted the page range in the published issue,but did not affect the scholarly content.To ensure consistency with the orig...The original online version of this article was revised:The layout update for Article 758 has impacted the page range in the published issue,but did not affect the scholarly content.To ensure consistency with the originally assigned pages(2595-2614),we will need to publish an erratum to correct the article and restore the original page range.The original article has been corrected.展开更多
There is an urgent need for the application of broadband Microwave Absorption(MA)structures on the leading edges of aircraft wings,which requires the MA structures to possess both the broadband MA performance and grea...There is an urgent need for the application of broadband Microwave Absorption(MA)structures on the leading edges of aircraft wings,which requires the MA structures to possess both the broadband MA performance and great surface conformability.To meet these requirements,we designed and fabricated a flexible bioinspired meta-structure with ultra-broadband MA,thin thickness and excellent surface conformality.The carbonyl iron powder-carbon nanotubes-polydimethylsiloxane composite was synthesized by physical blending method for fabricating the MA meta-structure.Through geometry-electromagnetic optimal design by heuristic optimization algorithm,the meta-structure mimicking to the nipple photonic nanostructures on the eyes of moth can achieve ultra-broadband MA performance of 35.14 GHz MA bandwidth(reflection loss≤–10 dB),covering 4.86–40.00 GHz,with thickness of only 4.3 mm.Through simple fabrication processes,the meta-structure has been successfully fabricated and bonded on wings’leading edges,exhibiting excellent surface conformability.Furthermore,the designed flexible MA meta-structure possesses significant Radar Cross-Section(RCS)reduction capability,as demonstrated by the RCS analysis of an unmanned aerial vehicle.This flexible ultra-broadband MA meta-structure provides an outstanding candidate to meet the radar stealth requirement of variable curvature structures on aircraft.展开更多
文摘Smoothly attaching the stretchable epidermal electronic devices(EEDs) onto the skin surface is highly desired to improve the measurement accuracy of electrophysiological signal.The paper presents an analytical approach to study interfacial mechanics of the 2D planar EEDs on the checkerboard buckling patterns of human skin.Energy variation method is proposed to determine a criterion whether EEDs laminate conformally onto the skin surface under undeformed and stretched cases.EEDs with low bending stiffness(thin,soft devices/backing layer),smooth and soft skin,and strong adhesion promote conformal contact.Furthermore,the adhesion energy at the EED/skin interface is measured by the homemade peeling experiment platform with different substrate thicknesses and areal coverages.The upper limit of the areal coverage for EED conformal contact with the skin is proposed with given EED/skin properties.Conformability of EEDs are validated by experiments with different substrate thickness,areal coverage and external loadings.It provides a design guideline for EED to conformally contact with the skin surface for more accurate biological signal monitoring.
基金funded by the National Research,Development and Inno-vation Office,Hungary(TKP2021-EGA-31,2020-1.1.2-PIACI-KFI-2020-00021,KKP_22 Project no.144180 and FK_23 Project no.146081).Support from Hungarian Research Network(Eötvös Loránd Research Network)grant no.SA-87/2021 and KEP-5/2021 are also acknowledged.Project no.RRF-2.3.1-21-2022-00015+1 种基金supported by the European Union,Recovery and Resilience Facility.The János Bolyai Research Fellowship(A.W.)of the Hungarian Academy of Sciences is greatly acknowledged.The authors acknowledge CF CryoEM of CIISB,Instruct-CZ Centre,supported by Ministry of Education,Youth and Sports,Czech Republic(MEYS CR)(no.LM2023042)European Regional Development Fund-Project"UP CIISB"(n0.CZ.02.1.01/0.0/0.0/18_046/0015974).
文摘Peptide-based assemblies have gained increasing attention in different areas of nanotechnology,drug delivery and molecular biology.Among these,non-natural β-peptide scaffolds are particularly promising,as their programmable and diverse secondary structures,high metabolic stability and strong self-association propensity can be easily exploited to create variable constructs.We have recently demonstrated that heterochiral,acyclic β^(3)-peptides assembled into striped lamellar nanostructures that induced antibacterial activity.The process of this assembly formation could be exploited in diverse areas,however identifying oligomerisation stages,and more importantly,controlling the spontaneous process at different levels is still lacking.In this study,a set of analogues heterochiral hexameric β^(3)-peptide sequences was investigated to understand how systematic,small variations of the sequences,such as single point mutation or N-terminal chemical modification,can influence the resulting assemblies and allow the control of formed morphologies.TEM and cryo-EM combined with molecular dynamics simulation enabled the identification and differentiation of morphological stages throughout the entire multi-step process.Depending on the position of the sequence modifications,the self-assembled structures formed small oligomers,individual protofibrils,extended,flat lamellae,bundles and macroscopic clusters.These results outline how the self-assembly process of short heterochiral β-peptides can be qualitatively fine-tuned by sequence modifications,which contribute to understanding the general peptide assembly processes for their fibrillar morphologies.
基金supported in part by the National Natural Science Foundation of China:61773330.
文摘Audio-visual speech recognition(AVSR),which integrates audio and visual modalities to improve recognition performance and robustness in noisy or adverse acoustic conditions,has attracted significant research interest.However,Conformer-based architectures remain computational expensive due to the quadratic increase in the spatial and temporal complexity of their softmax-based attention mechanisms with sequence length.In addition,Conformerbased architectures may not provide sufficient flexibility for modeling local dependencies at different granularities.To mitigate these limitations,this study introduces a novel AVSR framework based on a ReLU-based Sparse and Grouped Conformer(RSG-Conformer)architecture.Specifically,we propose a Global-enhanced Sparse Attention(GSA)module incorporating an efficient context restoration block to recover lost contextual cues.Concurrently,a Grouped-scale Convolution(GSC)module replaces the standard Conformer convolution module,providing adaptive local modeling across varying temporal resolutions.Furthermore,we integrate a Refined Intermediate Contextual CTC(RIC-CTC)supervision strategy.This approach applies progressively increasing loss weights combined with convolution-based context aggregation,thereby further relaxing the constraint of conditional independence inherent in standard CTC frameworks.Evaluations on the LRS2 and LRS3 benchmark validate the efficacy of our approach,with word error rates(WERs)reduced to 1.8%and 1.5%,respectively.These results further demonstrate and validate its state-of-the-art performance in AVSR tasks.
基金financial support from the National Key R&D Program of China(2023YFA1407100)the National Natural Science Foundation of China(22373026)+1 种基金Guangdong Science and Technology Department(2021B0301030005,STKJ2023072,GDZX2304005,GDZX2504001,and 2021QN02X538)Ioan Bâldea gratefully acknowledges computational support by the state of Baden-Württemberg through bwHPC and the German Research Foundation through Grant Nos.INST 40/575-1,35/1597-1,and 35/1134-1(JUSTUS 2,bwUniCluster 2/3,and bwForCluster/MLS&WISO/HELIX 2).
文摘Control over charge transport in molecular–scale devices requires a deep understanding of how minute structural changes influence electronic properties.Here,we demonstrate dual transport regimes in tunnel junctions of n-alk-1-yne(CnA)molecules with gold electrodes driven by conformational bifurcation—the emergence of two nearly isoenergetic(planar and skewed)molecular conformers(dihedral anglesα=180°andα≈65°at the alkyne terminus in the gas phase).Although the energy differences are small,these subtle conformational differences manifest as distinct transport behaviors,uncovered through unsupervised machine learning,which identified two junction groups:“short”and“long”chains,with distinct attenuation factors(β_(short)≈1.0 vs.β_(long)≈0.74)and contact conductances(G_(c,short)≈200μS vs.G_(c,long)≈8μS).This dramatic impact of the dihedral angle exceeds the impact of the inter-ring twist angle in biphenyl-based junctions and rivals changes induced by switching from gold to platinum electrodes or from monothiol to dithiol anchors in oligoacene and oligophenylene junctions.X-ray photoelectron spectroscopy(XPS)confirmed this bifurcation,linking the“short”and“long”groups to planar and skewed conformers,with dihedrals remarkably agreeing with the gas-phase values.This work establishes conformational bifurcation as a promising route for designing programmable nanotransport properties through anchor-group control.
基金financially supported by the National Natural Science Foundation of China (Nos. 22533003 and 22025302)financial support from the Ministry of Science and Technology of China (No. 2022YFA1203203)State Key Laboratory of Chemical Engineering (No. SKL-ChE23T01).
文摘Conformational entropy,one of the central concepts of polymer physics,is the key to revealing physical characteristics of polymers.Despite an increased repertoire of conformational-entropy effects in the structural formation,transition,and properties of polymer systems,the physical origin of conformational entropy remains less understood compared to interaction energy and other types of entropy.This review seeks to provide a conceptual framework unveiling several principles and rules of conformational entropy in governing the structures and properties of polymers,from the perspective of fundamental physics and statistical mechanics.First,we focus on the fundamentals of entropy in thermodynamics,leading to the theoretical basis for the elucidation of conformational entropy.Second,we delineate the physical nature of statistics and dissipation of conformational entropy and its essential dependence on the environmental heat bath.Next,we explore the principles of conformational entropy in driving the ordering transitions of various systems of polymers and their nanocomposites,elucidating the emergent and collective behaviors as well as the interplay between energetic interactions and entropy.Moreover,we demonstrate how the concept of conformational entropy is generalized to the biological systems and other soft matters.Finally,we discuss future directions to signify this framework originated from polymers.
基金financially supported by the National Natural Science Foundation of China(No.22273026)Scientific Research Innovation Capability Support Project for Young Faculty(No.ZYGXQNJSKYCXNLZCXM-I15)+3 种基金Basic and Applied Basic Research Foundation of Guangdong Province(2024A1515012401)GJYC program of Guangzhou(No.2024D03J0002)the China Postdoctoral Science Foundation(No.2024M750938)Postdoctoral Fellowship Program of CPSF(No.GZC20240492)for their financial support。
文摘In contrast to cyclic polymers with ring-like backbones,side-chain cyclization is another intriguing structural feature that has not been extensively studied.In this study,a library of orthogonally protected monomers featuring monocyclic,dicyclic,or tricyclic pendant motifs was designed and prepared based on malic acid derivatives.Polyesters with precise chemical structures and uniform chain lengths were prepared modularly through iterative growth.Meticulous control over the chemical details allows for a close investigation of the topological effects on the polymer properties.Compared to their linear side chain counterparts,the presence of cyclic pendant groups has a significant impact on chain conformation,leading to a reduction in hydrodynamic volume and an enhancement in the glass transition temperature.These results underscore the potential of tailoring polymer properties through rational engineering of side chain topology.
基金supported by the National Natural Science Foundation of China(Grant Nos.12432005 and 12472116)the Fundamental Research Funds for the Central Universities(DUTZD25240).
文摘Conformal truss-like lattice structures face significant manufacturability challenges in additive manufac-turing due to overhang angle limitations.To address this problem,we propose a novel angle-constrained optimization method grounded in the global adjustment of nodal coordinates.First,a build direction is selected to minimize the number of violating struts.Then,an angular-constraint matrix is assembled from strut direction vectors,and analytical sensitivities with respect to nodal coordinates are derived to enable efficient constrained optimization under nonlinear angular inequality constraints.Numerical studies on two complex curved-surface lattices demonstrate that all overhang violations are eliminated while only minor changes are induced in global stiffness and strength.In particular,the maximum displacement of an ergonomic insole varies by only 2.87%after optimization.The results confirm the method’s versatility and engineering robustness,providing a practical approach for additive manufacturing-oriented lattice structure design.
基金Supported by National Natural Science Foundation of China(Grant No.12171140).
文摘It is well known that critical points of the total scalar curvature functional S on the space of all smooth Riemannian structures of volume 1 on a compact manifold M are exactly the Einstein metrics.When the domain of S is restricted to the space of constant scalar curvature metrics,there has been a conjecture that a critical point is also Einstein or isometric to a standard sphere.In the Riemannian case,it’s tangent space satisfies a decomposition.In this paper,we prove that if we only consider the Hermitian metrics,it also have a decomposition.Then we obtain the equation of the critical points among the Hermitian metrics.
基金Supported by Science and Technology Development Plan Project of Jilin Province China(Grant No.20260102245JC)Supported by National Natural Science Foundation of China(Grant No.11771070).
文摘In this paper,we derive the sub-Riemannian version of the Kastler-Kalau-Walze type theorem and the Dabrowski-Sitarz-Zalecki type theorem for the twisted BCV spaces.We also compute the Connes conformal invariants for the twisted product,as well as the sub-Riemannian limits of the Connes conformal invariants for the twisted BCV spaces.
基金National Natural Science Foundation of China(No.U2241205)the Natural Science Basic Research Program of Shaanxi(Nos.2022JC-33,2023-GHZD-35,and 2024JC-ZDXM-25)+1 种基金the Fundamental Research Funds for the Central Universitiesthe National 111 Project to provide fund for conducting experiments。
文摘In this study,the design,analysis,manufacturing,and testing of a 3D-printed conformal microstrip array antenna for high-temperature environments is presented.3D printing technology is used to fabricate a curved ceramic substrate,and laser sintering and microdroplet spraying processes are used to add the conductive metal on the curved substrate.The problems of gain loss,bandwidth reduction,and frequency shift caused by high temperatures are addressed by using a proper antenna design,with parasitic patches,slots,and metal resonant cavities.The antenna prototype is characterized by the curved substrates and the conductive metals for the power dividers,the patch,and the ground plane;its performance is examined up to a temperature of 600℃in a muffle furnace and compared with the results from the numerical analysis.The results show that the antenna can effectively function at 600℃and even higher temperatures.
文摘The original online version of this article was revised:The layout update for Article 758 has impacted the page range in the published issue,but did not affect the scholarly content.To ensure consistency with the originally assigned pages(2595-2614),we will need to publish an erratum to correct the article and restore the original page range.The original article has been corrected.
基金supported by the Basic Research Development Program of China(No.JCKY2021607B036)the National Natural Science Foundation of China(No.52275512).
文摘There is an urgent need for the application of broadband Microwave Absorption(MA)structures on the leading edges of aircraft wings,which requires the MA structures to possess both the broadband MA performance and great surface conformability.To meet these requirements,we designed and fabricated a flexible bioinspired meta-structure with ultra-broadband MA,thin thickness and excellent surface conformality.The carbonyl iron powder-carbon nanotubes-polydimethylsiloxane composite was synthesized by physical blending method for fabricating the MA meta-structure.Through geometry-electromagnetic optimal design by heuristic optimization algorithm,the meta-structure mimicking to the nipple photonic nanostructures on the eyes of moth can achieve ultra-broadband MA performance of 35.14 GHz MA bandwidth(reflection loss≤–10 dB),covering 4.86–40.00 GHz,with thickness of only 4.3 mm.Through simple fabrication processes,the meta-structure has been successfully fabricated and bonded on wings’leading edges,exhibiting excellent surface conformability.Furthermore,the designed flexible MA meta-structure possesses significant Radar Cross-Section(RCS)reduction capability,as demonstrated by the RCS analysis of an unmanned aerial vehicle.This flexible ultra-broadband MA meta-structure provides an outstanding candidate to meet the radar stealth requirement of variable curvature structures on aircraft.
