Presetting tensile twins(TTs)can enhance the mechanical properties of magnesium(Mg)alloys.Two as-received(AR)sheets,as-received state-A(AR-A)with fiber texture and nonuniform grains and as-received state-B with basal ...Presetting tensile twins(TTs)can enhance the mechanical properties of magnesium(Mg)alloys.Two as-received(AR)sheets,as-received state-A(AR-A)with fiber texture and nonuniform grains and as-received state-B with basal texture and uniform equiaxial grains are selected to induce TTs via a novel method called corrugated wide limit alignment(CWLA),and the corresponding CWLA-processed sheets are denoted as CWLA-processed state-A(C-A)and CWLA-processed state-B(C-B).The results demonstrate that a larger initial average grain size correlates with a higher fraction of TTs induced in Mg sheets,thereby refining the grains and forming a new rolling direction(RD)tilted texture during CWLA.The ultimate tensile strength increases by 32%from AR-A to C-A,primarily due to refinement strengthening and twinning-induced strain hardening.The recrystallization mechanism of C-A is dominated by twinning-induced dynamic recrystallization(DRX),where DRX grains prefer to inherit the orientation of TTs,resulting in an enhanced RD-tilted texture and the formation of multi-modal texture.The recrystallization mechanism of C-B is mainly discontinuous DRX and continuous DRX,and the DRX grains prefer to inherit the orientation of matrix grains,ultimately forming a basal texture.In summary,the tensile mechanical behavior of pre-twinned Mg sheets significantly depends on the grain size and texture of the AR sheets,so they present similar changing trends during tensile deformation.展开更多
This study fabricates an AZ31 magnesium alloy tube by spinning technology-power stagger forward spinning.The microstructure evolution of the tube is investigated by combining electron backscatter diffraction and trans...This study fabricates an AZ31 magnesium alloy tube by spinning technology-power stagger forward spinning.The microstructure evolution of the tube is investigated by combining electron backscatter diffraction and transmission electron microscopy analysis,and the corrosion resistance is measured by an electrochemical corrosion test.Results show that the grains are obviously more uniform and finer along the wall thickness’s direction of the AZ31 alloy tube after the third spinning pass.The number of twins ascends first and then descends,while the varying trend of low-angle grain boundaries(LAGBs)is opposite to that of the twins as the spinning pass increases.With the increase of the total spinning deformation,the deformation texture initially increases and the c-axis of the{0001}crystal plane gradually rotates to the axial direction of the tube;the deformation texture then decreases and the orientation of grains becomes more random.The main mechanism of grain refinement is dynamic recrystallization by the twin-induced way and bowing out of the nucleation at grain boundaries during the first and second pass.However,the dominant mechanism of the refined grain is the high-temperature dynamic recovery in the third pass,and the microstructure mainly consists of substructured grains.After the spinning deformation,the corrosion resistance of the AZ31 alloy tube decreases due to the combined effect of twins and high density-dislocations.展开更多
Single-grain models with different cerium contents or structural parameters have been introduced to investigate the reversal magnetization behaviors in cerium-containing magnets. All the micromagnetic simulations are ...Single-grain models with different cerium contents or structural parameters have been introduced to investigate the reversal magnetization behaviors in cerium-containing magnets. All the micromagnetic simulations are carried out via the object oriented micromagnetic framework(OOMMF). As for single(Nd,Ce)_2 Fe_(14)B type grain, the coercivity decreases monotonously with the increase of the cerium content. Four types of grain structure have been compared: single(Nd,Ce)_2 Fe_(14)B type, core((Nd,Ce)_2 Fe_(14)B)-shell(Nd_2 Fe_(14)B) type with 2 nm thick shell, core(Ce_2 Fe_(14)B)-shell(Nd_2 Fe_(14)B) type, and core(Nd_2 Fe_(14)B)-shell(Ce_2 Fe_(14)B) type. It is found that core((Nd,Ce)_2 Fe_(14)B)-shell(Nd_2 Fe_(14)B)type grain with 2 nm thick shell always presents the largest coercivity under the same total cerium content. Furthermore,the relationship between the coercivity and the shell thickness t in core((Nd,Ce)_2 Fe_(14)B)-shell(Nd_2 Fe_(14)B) type grain has been studied. When the total cerium content is kept at 20.51 at.%, the analyzed results show that as t varies from 1 nm to 7 nm, the coercivity gradually ascends at the beginning, then quickly descends after reaching the maximum value when t = 5 nm. From the perspective of the positions of nucleation points, the reasons why t affects the coercivity are discussed in detail.展开更多
A novel Nd-Fe-B type permanent magnet with excellent thermal stability was designed by Co replacing Fe in the main phase and the grain boundary phase.The remanence and coercivity temperature coefficient reach 0.058%/...A novel Nd-Fe-B type permanent magnet with excellent thermal stability was designed by Co replacing Fe in the main phase and the grain boundary phase.The remanence and coercivity temperature coefficient reach 0.058%/℃and 0.465%/℃in the te mperature range from 25 to 100℃,which are much lower than those of commercial Nd-Fe-B magnet.An enhanced Curie temperature is obtained for the novel magnet due to the Co substitution,which significantly improves the operating temperature.The microstructure result reveals that an amorphous phase exists in the intergranular grains which is probably responsible for the deterioration of intrinsic coercivity.This work can provide a reference for the design and optimization of components of sintered Nd-Fe-B magnets with excellent thermal stability.展开更多
The high-temperature magnetic perfo rmance and micro structure of Sm_(1-x)Gd_(x)(Co_(bal)Fe_(0.09)Cu_(0.09)Zr_(0.025))_(7.2)(x=0.3,0.5) magnets were investigated.With the isothermal aging time decreasing from 11 to 3 ...The high-temperature magnetic perfo rmance and micro structure of Sm_(1-x)Gd_(x)(Co_(bal)Fe_(0.09)Cu_(0.09)Zr_(0.025))_(7.2)(x=0.3,0.5) magnets were investigated.With the isothermal aging time decreasing from 11 to 3 h,the temperature coefficient of intrinsic coercivity in the temperature range of 25-500℃,β_(25-500℃),was optimized from -0,167%/℃ to-0.112%/℃ for x=0.3 magnets.The noticeable enhancement(~33%) of temperature stability is correlated with the increased content of 1:5H cell boundary phase and its relatively high Curie temperature as well.However,for the x=0.5 magnet,it is found that the presence of Sm_(5)Co_(19) phases and wider nanotwin variants hinder the formation of 1:5H cell boundary phase.The insufficient 1:5H is not beneficial to the proper redistribution of Cu in cell boundary,making the x=0.5 magnet difficult to achieve higher temperature stability.Consequently,the approach of adjusting the isothermal aging process can offer guidance for attaining superior magnetic performance in the temperature range from 25 to 500℃ for Gd-substituted Sm_(2)Co_(17)-type magnets.展开更多
Pursuing higher data rate with limited spectral resources is a longstanding topic that has triggered the fast growth of modern wireless communication techniques.However,the massive deployment of active nodes to compen...Pursuing higher data rate with limited spectral resources is a longstanding topic that has triggered the fast growth of modern wireless communication techniques.However,the massive deployment of active nodes to compensate for propagation loss necessitates high hardware expenditure,energy consumption,and maintenance cost,as well as complicated network interference issues.Intelligent metasurfaces,composed of a number of subwavelength passive or active meta-atoms,have recently found to be a new paradigm to actively reshape wireless communication environment in a green way,distinct from conventional works that passively adapt to the surrounding.In this review,we offer a unified perspective on how intelligent metasurfaces can facilitate wireless communication in three manners:signal relay,signal transmitter,and signal processor.We start by the basic modeling of wireless channel and the evolution of metasurfaces from passive,active to intelligent metasurfaces.Integrated with various deep learning algorithms,intelligent metasurfaces adapt to cater for the ever-changing environments without human intervention.Then,we overview specific experimental advancements using intelligent metasurfaces.We conclude by identifying key issues in the practical implementations of intelligent metasurfaces,and surveying new directions,such as gain metasurfaces and knowledge migration.展开更多
Controlling electromagnetic(EM)waves at will is fundamentally important for diverse applications,ranging from optical microcavities,super-resolution imaging,to quantum information processing.Decades ago,the forays int...Controlling electromagnetic(EM)waves at will is fundamentally important for diverse applications,ranging from optical microcavities,super-resolution imaging,to quantum information processing.Decades ago,the forays into metamaterials and transformation optics have ignited unprecedented interest to create an invisibility cloak—a closed space with any object inside invisible.However,all features of the scattering waves become stochastic and uncontrollable when EM waves interact with an open and disordered environment,making an open invisible space almost impossible.Counterintuitively,here we for the first time present an open,cluttered,and dynamic but invisible space,wherein any freely-moving object maintains invisible.To adapt to the disordered environment,we randomly organize a swarm of reconfigurable metasurfaces,and master them by MetaSeeker,a population-based reinforcement learning(RL).MetaSeeker constructs a narcissistic internal world to mirror the stochastic physical world,capable of autonomous preferment,evolution,and adaptation.In the perception-decision-execution experiment,multiple RL agents automatically interact with the ever-changing environments and integrate a post-hoc explainability to visualize the decision-making process.The hidden objects,such as vehicle cluster and experimenter,can freely scale,race,and track in the invisible space,with the environmental similarity of 99.5%.Our results constitute a monumental stride to reshape the evolutionary landscape of metasurfaces from individual to swarm intelligence and usher in the remote management of entire EM space.展开更多
The conventional generalized Snell’s law(GSL),derived from classical laws of optical reflection and refraction,governs wavefront manipulation via phase gradients but neglects higher-order spatial harmonics inherently...The conventional generalized Snell’s law(GSL),derived from classical laws of optical reflection and refraction,governs wavefront manipulation via phase gradients but neglects higher-order spatial harmonics inherently excited by the mutual coupling among meta-atoms on a metasurface.Here,we introduce a spatial harmonic-expanded GSL(SH-GSL)framework by unifying phase-gradient control with Floquet periodicity,establishing spatial harmonics as independent degrees of freedom rather than conventional parasitic disturbances.The SH-GSL framework rigorously identifies the intrinsic harmonic dynamics inherent to metasurfaces,which is a critical feature absent in GSL.Furthermore,this framework further reveals that all gradient-phase metasurfaces inherently function as multichannel platforms due to full spatial harmonics,with this multifunctionality rooted in nonlocal Floquet-Bloch modal interactions.Experimental validation demonstrates:abnormal spatial-harmonic reflection with angular precision(<5°deviation),multi-beam splitting(dual/quad configurations)via the relationship between specific harmonics and compensation wave vectors,and a perfect three-channel retroreflector achieving up to 99%efficiency,where parasitic harmonics are confined to near-field plasmonic regimes.This framework establishes a deterministic Floquet-engineered momentum compensation mechanism to simultaneously activate target harmonic channels while confining parasitic harmonics to near-field plasmonic regimes.Experimental validation confirms the framework’s accuracy and scalability,bridging momentum-space physics with practical meta-plasmon systems.This work redefines metasurface engineering paradigms,unlocking advancements in ultra-dense beamforming,sensing,and meta-photonics through harmonic-division multiplexing.展开更多
The flexible and conformal interconnects for electronic systems as a potential signal transmission device have great prospects in body-worn or wearable applications.High-efficiency wave propagation and conformal struc...The flexible and conformal interconnects for electronic systems as a potential signal transmission device have great prospects in body-worn or wearable applications.High-efficiency wave propagation and conformal structure deformation around human body at radio communication are still confronted with huge challenges due to the lack of methods to control the wave propagation and achieve the deformable structure simultaneously.Here,inspired by the kirigami technology,a new paradigm to construct spoof plasmonic interconnects(SPIs)that support radiofrequency(RF)surface plasmonic transmission is proposed,together with high elasticity,strong robustness,and multifunction performance.Leveraging the strong field-confinement characteristic of spoof surface plasmons polaritons,the Type-I SPI opens its high-efficiency transmission band after stretching from a simply connected metallic surface.Meanwhile,the broadband transmission of the kirigami-based SPI exhibits strong robustness and excellent stability undergoing complex deformations,i.e.,bending,twisting,and stretching.In addition,the prepared Type-II SPI consisting of 2 different subunit cells can achieve band-stop transmission characteristics,with its center frequency dynamically tunable by stretching the buckled structure.Experimental measurements verify the on-off switching performance in kirigami interconnects triggered by stretching.Overcoming the mechanical limitation of rigid structure with kirigami technology,the designer SPIs exhibit high stretchability through out-of-plane structure deformation.Such kirigami-based interconnects can improve the elastic functionality of wearable RF electronics and offer high compatibility to large body motion in future body network systems.展开更多
The valley degree of freedom(DoF)plays a crucial role in valleytronics,paralleling the spin DoF in spintronics,and serves as a novel conduit for information and energy.In momentum space,valley DoF is characterized by ...The valley degree of freedom(DoF)plays a crucial role in valleytronics,paralleling the spin DoF in spintronics,and serves as a novel conduit for information and energy.In momentum space,valley DoF is characterized by discrete energy extremal states,which are present in conventional semiconductors and twodimensional(2D)crystal materials.Analogous wave behaviors in periodic structures allow for the application of valley dispersion relations to wave systems,including optics[1],acoustics[2,3],and water waves[4].When the wavelength is comparable to the period of an artificial crystal structure,classical waves experience strong Bragg scattering,resulting in a band gap and new propagation properties.Due to their macroscopic features and controllable geometric symmetry,these classical wave systems have become an ideal platform for studying topological physics.Although progress has been made in classical wave systems,conclusive evidence of topological valley states in water waves—a typical classical wave system—has not yet been obtained.展开更多
Pushing the information states'acquisition efficiency has been a long-held goal to reach the measurement precision limit inside scattering spaces.Recent studies have indicated that maximal information states can b...Pushing the information states'acquisition efficiency has been a long-held goal to reach the measurement precision limit inside scattering spaces.Recent studies have indicated that maximal information states can be attained through engineered modes;however,partial intrusion is generally required.While non-invasive designs have been substantially explored across diverse physical scenarios,the non-invasive acquisition of information states inside dynamic scattering spaces remains challenging due to the intractable non-unique mapping problem,particularly in the context of multi-target scenarios.Here,we establish the feasibility of non-invasive information states'acquisition experimentally for the first time by introducing a tandem-generated adversarial network framework inside dynamic scattering spaces.To illustrate the framework's efficacy,we demonstrate that efficient information states'acquisition for multi-target scenarios can achieve the Fisher information limit solely through the utilization of the external scattering matrix of the system.Our work provides insightful perspectives for precise measurements inside dynamic complex systems.展开更多
Metasurface modeling,designs,and applications using computational approaches are by now well established as an essential pillar in photonics,physics,and materials science.The past years have witnessed tremendous advan...Metasurface modeling,designs,and applications using computational approaches are by now well established as an essential pillar in photonics,physics,and materials science.The past years have witnessed tremendous advances in methodologies and technologies to unearth the intricate light–matter interaction and promote adaptive metadevices.They have pushed the studies of metasurfaces from early passive,reconfigurable modalities to the next generation of intelligent metasurfaces.In this review,we elaborate general architecture for intelligent metasurfaces,constructed by the algorithm layer,tunable metasurface layer,and application layer.We first discuss a variety of deep learning models,ranging from the fundamental neural networks inspired by computer science to sophisticated algorithms embedded with physical specialty,highlighting their potential in the forward prediction,inverse design,and spectral correlation of metasurfaces.We then discuss adaptive metadevices in the main applications of invisibility cloaks,smart vision,intelligent sensing,and wireless communication.Finally,we pinpoint current challenges and future perspectives to embrace the coming era of intelligent metasurfaces.展开更多
Robust three-dimensional(3D)recognition across different viewing angles is crucial for dynamic applications such as autonomous navigation and augmented reality;however,the application of the technology remains challen...Robust three-dimensional(3D)recognition across different viewing angles is crucial for dynamic applications such as autonomous navigation and augmented reality;however,the application of the technology remains challenging owing to factors such as orientation,deformation,and noise.Wave-based analogous computing,particularly diffraction neural networks(DNNs),constitutes a scan-free,energy-efficient means of mitigating these issues with strong resilience to environmental disturbances.Herein,we present a real-time all-directional 3D object recognition and distortion correction system using a deep knowledge prior DNN.Our approach effectively addressed complex two-dimensional(2D)and 3D distortions by optimizing the metasurface parameters with minimal training data and refining them using DNNs.Experimental results demonstrate that the system can effectively rectify distortions and recognize objects in real time,even under varying perspectives and multiple complex distortions.In 3D recognition,the prior DNN reliably identifies both dynamic and static objects,maintaining stable performance despite arbitrary orientation changes,highlighting its adaptability to complex and dynamic environments.Our system can function either as a preprocessing tool for imaging platforms or as a stand-alone solution,facilitating 3D recognition tasks such as motion sensing and facial recognition.It offers a scalable solution for high-speed recognition tasks in dynamic and resource-constrained applications.展开更多
The integration of artificial intelligence with electromagnetic metasurfaces has inaugurated a new era of intelligent metasurfaces,enabling self-adaptive ability for various user demands and in complex environments.Ho...The integration of artificial intelligence with electromagnetic metasurfaces has inaugurated a new era of intelligent metasurfaces,enabling self-adaptive ability for various user demands and in complex environments.However,inverse design,as the core of intelligent metasurfaces,is typically trained based on an assumption of ideal input,thus failing to maintain robustness against complex real-world signal distortions.展开更多
Mycophenolic acid(MPA),the active moiety of both mycophenolate mofetil(MMF)and enteric-coated mycophenolate sodium(EC-MPS),serves as a primary immunosuppressant for maintaining solid organ transplants.Therapeutic drug...Mycophenolic acid(MPA),the active moiety of both mycophenolate mofetil(MMF)and enteric-coated mycophenolate sodium(EC-MPS),serves as a primary immunosuppressant for maintaining solid organ transplants.Therapeutic drug monitoring(TDM)enhances treatment outcomes through tailored approaches.This study aimed to develop an evidence-based guideline for MPA TDM,facilitating its rational application in clinical settings.The guideline plan was drawn from the Institute of Medicine and World Health Organization(WHO)guidelines.Using the Delphi method,clinical questions and outcome indicators were generated.Systematic reviews,Grading of Recommendations Assessment,Development,and Evaluation(GRADE)evidence quality evaluations,expert opinions,and patient values guided evidence-based suggestions for the guideline.External reviews further refined the recommendations.The guideline for the TDM of MPA(IPGRP-2020CN099)consists of four sections and 16 recommendations encompassing target populations,monitoring strategies,dosage regimens,and influencing factors.High-risk populations,timing of TDM,area under the curve(AUC)versus trough concentration(C0),target concentration ranges,monitoring frequency,and analytical methods are addressed.Formulation-specific recommendations,initial dosage regimens,populations with unique considerations,pharmacokinetic-informed dosing,body weight factors,pharmacogenetics,and drug–drug interactions are covered.The evidence-based guideline offers a comprehensive recommendation for solid organ transplant recipients undergoing MPA therapy,promoting standardization of MPA TDM,and enhancing treatment efficacy and safety.展开更多
Matrix computation,as a fundamental building block of information processing in science and technology,contributes most of the computational overheads in modern signal processing and artificial intelligence algorithms...Matrix computation,as a fundamental building block of information processing in science and technology,contributes most of the computational overheads in modern signal processing and artificial intelligence algorithms.Photonic accelerators are designed to accelerate specific categories of computing in the optical domain,especially matrix multiplication,to address the growing demand for computing resources and capacity.Photonic matrix multiplication has much potential to expand the domain of telecommunication,and artificial intelligence benefiting from its superior performance.Recent research in photonic matrix multiplication has flourished and may provide opportunities to develop applications that are unachievable at present by conventional electronic processors.In this review,we first introduce the methods of photonic matrix multiplication,mainly including the plane light conversion method,Mach–Zehnder interferometer method and wavelength division multiplexing method.We also summarize the developmental milestones of photonic matrix multiplication and the related applications.Then,we review their detailed advances in applications to optical signal processing and artificial neural networks in recent years.Finally,we comment on the challenges and perspectives of photonic matrix multiplication and photonic acceleration.展开更多
Optical logic operations lie at the heart of optical computing,and they enable many applications such as ultrahighspeed information processing.However,the reported optical logic gates rely heavily on the precise contr...Optical logic operations lie at the heart of optical computing,and they enable many applications such as ultrahighspeed information processing.However,the reported optical logic gates rely heavily on the precise control of input light signals,including their phase difference,polarization,and intensity and the size of the incident beams.Due to the complexity and difficulty in these precise controls,the two output optical logic states may suffer from an inherent instability and a low contrast ratio of intensity.Moreover,the miniaturization of optical logic gates becomes difficult if the extra bulky apparatus for these controls is considered.As such,it is desirable to get rid of these complicated controls and to achieve full logic functionality in a compact photonic system.Such a goal remains challenging.Here,we introduce a simple yet universal design strategy,capable of using plane waves as the incident signal,to perform optical logic operations via a diffractive neural network.Physically,the incident plane wave is first spatially encoded by a specific logic operation at the input layer and further decoded through the hidden layers,namely,a compound Huygens’metasurface.That is,the judiciously designed metasurface scatters the encoded light into one of two small designated areas at the output layer,which provides the information of output logic states.Importantly,after training of the diffractive neural network,all seven basic types of optical logic operations can be realized by the same metasurface.As a conceptual illustration,three logic operations(NOT,OR,and AND)are experimentally demonstrated at microwave frequencies.展开更多
Recent advances in non-radiative wireless power transfer(WPT)technique essentially relying on magnetic resonance and near-field coupling have successfully enabled a wide range of applications.However,WPT systems based...Recent advances in non-radiative wireless power transfer(WPT)technique essentially relying on magnetic resonance and near-field coupling have successfully enabled a wide range of applications.However,WPT systems based on double resonators are severely limited to short-or mid-range distance,due to the deteriorating efficiency and power with long transfer distance.WPT systems based on multi-relay resonators can overcome this problem,which,however,suffer from sensitivity to perturbations and fabrication imperfections.Here,we experimentally demonstrate a concept of topological wireless power transfer(TWPT),where energy is transferred efficiently via the near-field coupling between two topological edge states localized at the ends of a one-dimensional radiowave topological insulator.Such a TWPT system can be modelled as a parity-time-symmetric Su-Schrieffer-Heeger(SSH)chain with complex boundary potentials.Besides,the coil configurations are judiciously designed,which significantly suppress the unwanted cross-couplings between nonadjacent coils that could break the chiral symmetry of the SSH chain.By tuning the inter-and intra-cell coupling strengths,we theoretically and experimentally demonstrate high energy transfer efficiency near the exceptional point of the topological edge states,even in the presence of disorder.The combination of topological metamaterials,non-Hermitian physics,and WPT techniques could promise a variety of robust,efficient WPT applications over long distances in electronics,transportation,and industry.展开更多
Recent breakthroughs in deep learning have ushered in an essential tool for optics and photonics,recurring in various applications of material design,system optimization,and automation control.Deep learning-enabled on...Recent breakthroughs in deep learning have ushered in an essential tool for optics and photonics,recurring in various applications of material design,system optimization,and automation control.Deep learning-enabled on-demand metasurface design has been the subject of extensive expansion,as it can alleviate the time-consuming,low-efficiency,and experience-orientated shortcomings in conventional numerical simulations and physics-based methods.However,collecting samples and training neural networks are fundamentally confined to predefined individual metamaterials and tend to fail for large problem sizes.Inspired by object-oriented C++programming,we propose a knowledge-inherited paradigm for multi-object and shape-unbound metasurface inverse design.Each inherited neural network carries knowledge from the"parent"metasurface and then is freely assembled to construct the"offspring"metasurface;such a process is as simple as building a container-type house.We benchmark the paradigm by the free design of aperiodic and periodic metasurfaces,with accuracies that reach 86.7%.Furthermore,we present an intelligent origami metasurface to facilitate compatible and lightweight satellite communication facilities.Our work opens up a new avenue for automatic metasurface design and leverages the assemblability to broaden the adaptability of intelligent metadevices.展开更多
Being invisible at will has been a long-standing dream for centuries, epitomized by numerous legends;humans have never stopped their exploration steps to realize this dream. Recent years have witnessed a breakthrough ...Being invisible at will has been a long-standing dream for centuries, epitomized by numerous legends;humans have never stopped their exploration steps to realize this dream. Recent years have witnessed a breakthrough in this search due to the advent of transformation optics, metamaterials, and metasurfaces. However, the previous metasurface cloaks typically work in a reflection manner that relies on a high-reflection background, thus limiting the applications. Here, we propose an easy yet viable approach to realize the transmitted metasurface cloak, just composed of two planar metasurfaces to hide an object inside, such as a cat. To tackle the hard-to-converge issue caused by the nonuniqueness phenomenon, we deploy a tandem neural network(T-NN) to efficiently streamline the inverse design. Once pretrained, the T-NN can work for a customer-desired electromagnetic response in one single forward computation, saving a great amount of time. Our work opens a new avenue to realize a transparent invisibility cloak, and the tandem-NN can also inspire the inverse design of other metamaterials and photonics.展开更多
基金supported by the National Natural Science Foundation of China(No.52005362)the Fundamental Research Program of Shanxi Province(Nos.202303021221005 and 202303021211045)+1 种基金the Patent Commercialization Program of Shanxi Province(No.202402003)the Key Research and Development Plan of Xinzhou City.
文摘Presetting tensile twins(TTs)can enhance the mechanical properties of magnesium(Mg)alloys.Two as-received(AR)sheets,as-received state-A(AR-A)with fiber texture and nonuniform grains and as-received state-B with basal texture and uniform equiaxial grains are selected to induce TTs via a novel method called corrugated wide limit alignment(CWLA),and the corresponding CWLA-processed sheets are denoted as CWLA-processed state-A(C-A)and CWLA-processed state-B(C-B).The results demonstrate that a larger initial average grain size correlates with a higher fraction of TTs induced in Mg sheets,thereby refining the grains and forming a new rolling direction(RD)tilted texture during CWLA.The ultimate tensile strength increases by 32%from AR-A to C-A,primarily due to refinement strengthening and twinning-induced strain hardening.The recrystallization mechanism of C-A is dominated by twinning-induced dynamic recrystallization(DRX),where DRX grains prefer to inherit the orientation of TTs,resulting in an enhanced RD-tilted texture and the formation of multi-modal texture.The recrystallization mechanism of C-B is mainly discontinuous DRX and continuous DRX,and the DRX grains prefer to inherit the orientation of matrix grains,ultimately forming a basal texture.In summary,the tensile mechanical behavior of pre-twinned Mg sheets significantly depends on the grain size and texture of the AR sheets,so they present similar changing trends during tensile deformation.
基金supported by the National Natural Science Foundation of China (Nos. 51805358 and 51775366)Key Research and Development Program of Jinzhong (No. Y201023)College Students’ Innovative Entrepreneurial Training Plan Program (No. 202010112011)
文摘This study fabricates an AZ31 magnesium alloy tube by spinning technology-power stagger forward spinning.The microstructure evolution of the tube is investigated by combining electron backscatter diffraction and transmission electron microscopy analysis,and the corrosion resistance is measured by an electrochemical corrosion test.Results show that the grains are obviously more uniform and finer along the wall thickness’s direction of the AZ31 alloy tube after the third spinning pass.The number of twins ascends first and then descends,while the varying trend of low-angle grain boundaries(LAGBs)is opposite to that of the twins as the spinning pass increases.With the increase of the total spinning deformation,the deformation texture initially increases and the c-axis of the{0001}crystal plane gradually rotates to the axial direction of the tube;the deformation texture then decreases and the orientation of grains becomes more random.The main mechanism of grain refinement is dynamic recrystallization by the twin-induced way and bowing out of the nucleation at grain boundaries during the first and second pass.However,the dominant mechanism of the refined grain is the high-temperature dynamic recovery in the third pass,and the microstructure mainly consists of substructured grains.After the spinning deformation,the corrosion resistance of the AZ31 alloy tube decreases due to the combined effect of twins and high density-dislocations.
基金supported by the National Natural Science Foundation of China(Grant Nos.51590882 and 51871063)
文摘Single-grain models with different cerium contents or structural parameters have been introduced to investigate the reversal magnetization behaviors in cerium-containing magnets. All the micromagnetic simulations are carried out via the object oriented micromagnetic framework(OOMMF). As for single(Nd,Ce)_2 Fe_(14)B type grain, the coercivity decreases monotonously with the increase of the cerium content. Four types of grain structure have been compared: single(Nd,Ce)_2 Fe_(14)B type, core((Nd,Ce)_2 Fe_(14)B)-shell(Nd_2 Fe_(14)B) type with 2 nm thick shell, core(Ce_2 Fe_(14)B)-shell(Nd_2 Fe_(14)B) type, and core(Nd_2 Fe_(14)B)-shell(Ce_2 Fe_(14)B) type. It is found that core((Nd,Ce)_2 Fe_(14)B)-shell(Nd_2 Fe_(14)B)type grain with 2 nm thick shell always presents the largest coercivity under the same total cerium content. Furthermore,the relationship between the coercivity and the shell thickness t in core((Nd,Ce)_2 Fe_(14)B)-shell(Nd_2 Fe_(14)B) type grain has been studied. When the total cerium content is kept at 20.51 at.%, the analyzed results show that as t varies from 1 nm to 7 nm, the coercivity gradually ascends at the beginning, then quickly descends after reaching the maximum value when t = 5 nm. From the perspective of the positions of nucleation points, the reasons why t affects the coercivity are discussed in detail.
基金Project supported by the National Key Research and Development Program(2021YFB3502801,2021YFB3502803)the National Natural Science Foundation of China(52001067)。
文摘A novel Nd-Fe-B type permanent magnet with excellent thermal stability was designed by Co replacing Fe in the main phase and the grain boundary phase.The remanence and coercivity temperature coefficient reach 0.058%/℃and 0.465%/℃in the te mperature range from 25 to 100℃,which are much lower than those of commercial Nd-Fe-B magnet.An enhanced Curie temperature is obtained for the novel magnet due to the Co substitution,which significantly improves the operating temperature.The microstructure result reveals that an amorphous phase exists in the intergranular grains which is probably responsible for the deterioration of intrinsic coercivity.This work can provide a reference for the design and optimization of components of sintered Nd-Fe-B magnets with excellent thermal stability.
基金Project supported by the National Key Research and Development Program of China (2021YFB3503100,2022YFB3505303,2021YFB3501500)the Key Technology Research and Development Program of Shandong Province (2019JZZY020210)。
文摘The high-temperature magnetic perfo rmance and micro structure of Sm_(1-x)Gd_(x)(Co_(bal)Fe_(0.09)Cu_(0.09)Zr_(0.025))_(7.2)(x=0.3,0.5) magnets were investigated.With the isothermal aging time decreasing from 11 to 3 h,the temperature coefficient of intrinsic coercivity in the temperature range of 25-500℃,β_(25-500℃),was optimized from -0,167%/℃ to-0.112%/℃ for x=0.3 magnets.The noticeable enhancement(~33%) of temperature stability is correlated with the increased content of 1:5H cell boundary phase and its relatively high Curie temperature as well.However,for the x=0.5 magnet,it is found that the presence of Sm_(5)Co_(19) phases and wider nanotwin variants hinder the formation of 1:5H cell boundary phase.The insufficient 1:5H is not beneficial to the proper redistribution of Cu in cell boundary,making the x=0.5 magnet difficult to achieve higher temperature stability.Consequently,the approach of adjusting the isothermal aging process can offer guidance for attaining superior magnetic performance in the temperature range from 25 to 500℃ for Gd-substituted Sm_(2)Co_(17)-type magnets.
基金sponsored by the Key Research and Development Program of the Ministry of Science and Technology under Grant Nos.2022YFA1404704,2022YFA1405200,and 2022YFA1404902the National Natural Science Foundation of China(NNSFC)under Grant Nos.62422514,62471432,62101485 and 61975176+1 种基金the Key Research and Development Program of Zhejiang Province under Grant No.2022C01036the Fundamental Research Funds for the Central Universities.
文摘Pursuing higher data rate with limited spectral resources is a longstanding topic that has triggered the fast growth of modern wireless communication techniques.However,the massive deployment of active nodes to compensate for propagation loss necessitates high hardware expenditure,energy consumption,and maintenance cost,as well as complicated network interference issues.Intelligent metasurfaces,composed of a number of subwavelength passive or active meta-atoms,have recently found to be a new paradigm to actively reshape wireless communication environment in a green way,distinct from conventional works that passively adapt to the surrounding.In this review,we offer a unified perspective on how intelligent metasurfaces can facilitate wireless communication in three manners:signal relay,signal transmitter,and signal processor.We start by the basic modeling of wireless channel and the evolution of metasurfaces from passive,active to intelligent metasurfaces.Integrated with various deep learning algorithms,intelligent metasurfaces adapt to cater for the ever-changing environments without human intervention.Then,we overview specific experimental advancements using intelligent metasurfaces.We conclude by identifying key issues in the practical implementations of intelligent metasurfaces,and surveying new directions,such as gain metasurfaces and knowledge migration.
基金sponsored by the Key Research and Development Program of the Ministry of Science and Technology under Grant Nos.2022YFA1404704,2022YFA1405200,and 2022YFA1404902the National Natural Science Foundation of China(NNSFC)under Grant Nos.62422514,62471432,and 62101485+1 种基金the Key Research and Development Program of Zhejiang Province under Grant No.2022C01036the Fundamental Research Funds for the Central Universities.
文摘Controlling electromagnetic(EM)waves at will is fundamentally important for diverse applications,ranging from optical microcavities,super-resolution imaging,to quantum information processing.Decades ago,the forays into metamaterials and transformation optics have ignited unprecedented interest to create an invisibility cloak—a closed space with any object inside invisible.However,all features of the scattering waves become stochastic and uncontrollable when EM waves interact with an open and disordered environment,making an open invisible space almost impossible.Counterintuitively,here we for the first time present an open,cluttered,and dynamic but invisible space,wherein any freely-moving object maintains invisible.To adapt to the disordered environment,we randomly organize a swarm of reconfigurable metasurfaces,and master them by MetaSeeker,a population-based reinforcement learning(RL).MetaSeeker constructs a narcissistic internal world to mirror the stochastic physical world,capable of autonomous preferment,evolution,and adaptation.In the perception-decision-execution experiment,multiple RL agents automatically interact with the ever-changing environments and integrate a post-hoc explainability to visualize the decision-making process.The hidden objects,such as vehicle cluster and experimenter,can freely scale,race,and track in the invisible space,with the environmental similarity of 99.5%.Our results constitute a monumental stride to reshape the evolutionary landscape of metasurfaces from individual to swarm intelligence and usher in the remote management of entire EM space.
基金supported by the National Natural Science Foundation of China(62271011)and(62405009)the National Science Key Lab Fund(2024CXPTGFJJ020010401)+1 种基金the National Key Research and Development Program of China(2021YFA1600302)the Beijing Science Foundation for Distinguished Young Scholars(JQ21011).
文摘The conventional generalized Snell’s law(GSL),derived from classical laws of optical reflection and refraction,governs wavefront manipulation via phase gradients but neglects higher-order spatial harmonics inherently excited by the mutual coupling among meta-atoms on a metasurface.Here,we introduce a spatial harmonic-expanded GSL(SH-GSL)framework by unifying phase-gradient control with Floquet periodicity,establishing spatial harmonics as independent degrees of freedom rather than conventional parasitic disturbances.The SH-GSL framework rigorously identifies the intrinsic harmonic dynamics inherent to metasurfaces,which is a critical feature absent in GSL.Furthermore,this framework further reveals that all gradient-phase metasurfaces inherently function as multichannel platforms due to full spatial harmonics,with this multifunctionality rooted in nonlocal Floquet-Bloch modal interactions.Experimental validation demonstrates:abnormal spatial-harmonic reflection with angular precision(<5°deviation),multi-beam splitting(dual/quad configurations)via the relationship between specific harmonics and compensation wave vectors,and a perfect three-channel retroreflector achieving up to 99%efficiency,where parasitic harmonics are confined to near-field plasmonic regimes.This framework establishes a deterministic Floquet-engineered momentum compensation mechanism to simultaneously activate target harmonic channels while confining parasitic harmonics to near-field plasmonic regimes.Experimental validation confirms the framework’s accuracy and scalability,bridging momentum-space physics with practical meta-plasmon systems.This work redefines metasurface engineering paradigms,unlocking advancements in ultra-dense beamforming,sensing,and meta-photonics through harmonic-division multiplexing.
基金the Key Research and Development Program of the Ministry of Science and Technology(2022YFA1404704,2022YFA1405200,and 2022YFA1404902)the National Natural Science Foundation of China(NNSFC)(62222115,62171407,61975176,and 62201500)+1 种基金the Key Research and Development Program of Zhejiang Province(2022C01036)the Fundamental Research Funds for the Central Universities.
文摘The flexible and conformal interconnects for electronic systems as a potential signal transmission device have great prospects in body-worn or wearable applications.High-efficiency wave propagation and conformal structure deformation around human body at radio communication are still confronted with huge challenges due to the lack of methods to control the wave propagation and achieve the deformable structure simultaneously.Here,inspired by the kirigami technology,a new paradigm to construct spoof plasmonic interconnects(SPIs)that support radiofrequency(RF)surface plasmonic transmission is proposed,together with high elasticity,strong robustness,and multifunction performance.Leveraging the strong field-confinement characteristic of spoof surface plasmons polaritons,the Type-I SPI opens its high-efficiency transmission band after stretching from a simply connected metallic surface.Meanwhile,the broadband transmission of the kirigami-based SPI exhibits strong robustness and excellent stability undergoing complex deformations,i.e.,bending,twisting,and stretching.In addition,the prepared Type-II SPI consisting of 2 different subunit cells can achieve band-stop transmission characteristics,with its center frequency dynamically tunable by stretching the buckled structure.Experimental measurements verify the on-off switching performance in kirigami interconnects triggered by stretching.Overcoming the mechanical limitation of rigid structure with kirigami technology,the designer SPIs exhibit high stretchability through out-of-plane structure deformation.Such kirigami-based interconnects can improve the elastic functionality of wearable RF electronics and offer high compatibility to large body motion in future body network systems.
基金sponsored by the National Natural Science Foundation of China(62475228 and 62275231)the Key Research and Development Program of the Ministry of Science and Technology(2022YFA1404704,2022YFA1405200 and 2022YFA1404902)+1 种基金the Key Research and Development Program of Zhejiang Province(2022C01036)the Fundamental Research Funds for the Central Universities。
文摘The valley degree of freedom(DoF)plays a crucial role in valleytronics,paralleling the spin DoF in spintronics,and serves as a novel conduit for information and energy.In momentum space,valley DoF is characterized by discrete energy extremal states,which are present in conventional semiconductors and twodimensional(2D)crystal materials.Analogous wave behaviors in periodic structures allow for the application of valley dispersion relations to wave systems,including optics[1],acoustics[2,3],and water waves[4].When the wavelength is comparable to the period of an artificial crystal structure,classical waves experience strong Bragg scattering,resulting in a band gap and new propagation properties.Due to their macroscopic features and controllable geometric symmetry,these classical wave systems have become an ideal platform for studying topological physics.Although progress has been made in classical wave systems,conclusive evidence of topological valley states in water waves—a typical classical wave system—has not yet been obtained.
基金Zhejiang University was sponsored by the National Natural Science Foundation of China(NNSFC)under grant nos.62071424,62201499,and 62027805。
文摘Pushing the information states'acquisition efficiency has been a long-held goal to reach the measurement precision limit inside scattering spaces.Recent studies have indicated that maximal information states can be attained through engineered modes;however,partial intrusion is generally required.While non-invasive designs have been substantially explored across diverse physical scenarios,the non-invasive acquisition of information states inside dynamic scattering spaces remains challenging due to the intractable non-unique mapping problem,particularly in the context of multi-target scenarios.Here,we establish the feasibility of non-invasive information states'acquisition experimentally for the first time by introducing a tandem-generated adversarial network framework inside dynamic scattering spaces.To illustrate the framework's efficacy,we demonstrate that efficient information states'acquisition for multi-target scenarios can achieve the Fisher information limit solely through the utilization of the external scattering matrix of the system.Our work provides insightful perspectives for precise measurements inside dynamic complex systems.
基金sponsored by the National Key Research and Development Program(Ministry of Science and Technology,Grant Nos.2022YFA1404704,2022YFA1405200,and 2022YFA1404902)the National Natural Science Foundation of China(NNSFC)(Grant Nos.61975176,62422514,62471432,and 62101485)+1 种基金the Key Research and Development Program of Zhejiang Province(Grant No.2022C01036)the Fundamental Research Funds for the Central Universities.
文摘Metasurface modeling,designs,and applications using computational approaches are by now well established as an essential pillar in photonics,physics,and materials science.The past years have witnessed tremendous advances in methodologies and technologies to unearth the intricate light–matter interaction and promote adaptive metadevices.They have pushed the studies of metasurfaces from early passive,reconfigurable modalities to the next generation of intelligent metasurfaces.In this review,we elaborate general architecture for intelligent metasurfaces,constructed by the algorithm layer,tunable metasurface layer,and application layer.We first discuss a variety of deep learning models,ranging from the fundamental neural networks inspired by computer science to sophisticated algorithms embedded with physical specialty,highlighting their potential in the forward prediction,inverse design,and spectral correlation of metasurfaces.We then discuss adaptive metadevices in the main applications of invisibility cloaks,smart vision,intelligent sensing,and wireless communication.Finally,we pinpoint current challenges and future perspectives to embrace the coming era of intelligent metasurfaces.
基金supported by the National Key Research and Development Program of China (Grant Nos. 2022YFA1404704, 2022YFA1405200, and 2022YFA1404902)the National Natural Science Foundation of China (NNSFC) (Grant Nos. 61975176 and 62071423)+3 种基金the Key Research and Development Program of Zhejiang Province (Grant Nos. 2022C01036 and 2024C01160)the Natural Science Foundation of Zhejiang Province (Grant No. LR23F010004)the Top-Notch Young Talent of Zhejiang Provincethe Fundamental Research Funds for the Central Universities
文摘Robust three-dimensional(3D)recognition across different viewing angles is crucial for dynamic applications such as autonomous navigation and augmented reality;however,the application of the technology remains challenging owing to factors such as orientation,deformation,and noise.Wave-based analogous computing,particularly diffraction neural networks(DNNs),constitutes a scan-free,energy-efficient means of mitigating these issues with strong resilience to environmental disturbances.Herein,we present a real-time all-directional 3D object recognition and distortion correction system using a deep knowledge prior DNN.Our approach effectively addressed complex two-dimensional(2D)and 3D distortions by optimizing the metasurface parameters with minimal training data and refining them using DNNs.Experimental results demonstrate that the system can effectively rectify distortions and recognize objects in real time,even under varying perspectives and multiple complex distortions.In 3D recognition,the prior DNN reliably identifies both dynamic and static objects,maintaining stable performance despite arbitrary orientation changes,highlighting its adaptability to complex and dynamic environments.Our system can function either as a preprocessing tool for imaging platforms or as a stand-alone solution,facilitating 3D recognition tasks such as motion sensing and facial recognition.It offers a scalable solution for high-speed recognition tasks in dynamic and resource-constrained applications.
基金supported by the National Natural Science Foundation of China(Grant Nos.62550050,62422514,and 62471432 for C.Q.,U25A20520 and 62475228 for H.C.)the Natural Science Foundation of Zhejiang Province,China(Grant No.LZ26F010004 for C.Q.)。
文摘The integration of artificial intelligence with electromagnetic metasurfaces has inaugurated a new era of intelligent metasurfaces,enabling self-adaptive ability for various user demands and in complex environments.However,inverse design,as the core of intelligent metasurfaces,is typically trained based on an assumption of ideal input,thus failing to maintain robustness against complex real-world signal distortions.
基金supported by the National Natural Science Foundation of China(NSFC)(No.72304007)the Huatong Guokang Medical Research Fund(No.2023HT010)。
文摘Mycophenolic acid(MPA),the active moiety of both mycophenolate mofetil(MMF)and enteric-coated mycophenolate sodium(EC-MPS),serves as a primary immunosuppressant for maintaining solid organ transplants.Therapeutic drug monitoring(TDM)enhances treatment outcomes through tailored approaches.This study aimed to develop an evidence-based guideline for MPA TDM,facilitating its rational application in clinical settings.The guideline plan was drawn from the Institute of Medicine and World Health Organization(WHO)guidelines.Using the Delphi method,clinical questions and outcome indicators were generated.Systematic reviews,Grading of Recommendations Assessment,Development,and Evaluation(GRADE)evidence quality evaluations,expert opinions,and patient values guided evidence-based suggestions for the guideline.External reviews further refined the recommendations.The guideline for the TDM of MPA(IPGRP-2020CN099)consists of four sections and 16 recommendations encompassing target populations,monitoring strategies,dosage regimens,and influencing factors.High-risk populations,timing of TDM,area under the curve(AUC)versus trough concentration(C0),target concentration ranges,monitoring frequency,and analytical methods are addressed.Formulation-specific recommendations,initial dosage regimens,populations with unique considerations,pharmacokinetic-informed dosing,body weight factors,pharmacogenetics,and drug–drug interactions are covered.The evidence-based guideline offers a comprehensive recommendation for solid organ transplant recipients undergoing MPA therapy,promoting standardization of MPA TDM,and enhancing treatment efficacy and safety.
基金Chaoran Huang would like to thank Alexander Tait,Bhavin Shastri and Paul Prucnal for the fruitful discussions.J.J.D.acknowledges the support of the National Key Research and Development Project of China(2018YFB2201901)the National Natural Science Foundation of China(61805090,62075075).
文摘Matrix computation,as a fundamental building block of information processing in science and technology,contributes most of the computational overheads in modern signal processing and artificial intelligence algorithms.Photonic accelerators are designed to accelerate specific categories of computing in the optical domain,especially matrix multiplication,to address the growing demand for computing resources and capacity.Photonic matrix multiplication has much potential to expand the domain of telecommunication,and artificial intelligence benefiting from its superior performance.Recent research in photonic matrix multiplication has flourished and may provide opportunities to develop applications that are unachievable at present by conventional electronic processors.In this review,we first introduce the methods of photonic matrix multiplication,mainly including the plane light conversion method,Mach–Zehnder interferometer method and wavelength division multiplexing method.We also summarize the developmental milestones of photonic matrix multiplication and the related applications.Then,we review their detailed advances in applications to optical signal processing and artificial neural networks in recent years.Finally,we comment on the challenges and perspectives of photonic matrix multiplication and photonic acceleration.
基金sponsored by the National Natural Science Foundation of China(NNSFC)under Grants Nos.61625502,11961141010,and 61975176the Top-Notch Young Talents Programme of China+4 种基金the Fundamental Research Funds for the Central UniversitiesNanyang Technological University for NAP Start-Up Grantthe Singapore Ministry of Education(Grant Nos.MOE2018-T2-1-022(S),MOE2016-T3-1-006 and Tier 1 RG174/16(S))supported by the Chinese Scholarship Council(CSC No.201906320294)Zhejiang University Academic Award for Outstanding Doctoral Candidates.
文摘Optical logic operations lie at the heart of optical computing,and they enable many applications such as ultrahighspeed information processing.However,the reported optical logic gates rely heavily on the precise control of input light signals,including their phase difference,polarization,and intensity and the size of the incident beams.Due to the complexity and difficulty in these precise controls,the two output optical logic states may suffer from an inherent instability and a low contrast ratio of intensity.Moreover,the miniaturization of optical logic gates becomes difficult if the extra bulky apparatus for these controls is considered.As such,it is desirable to get rid of these complicated controls and to achieve full logic functionality in a compact photonic system.Such a goal remains challenging.Here,we introduce a simple yet universal design strategy,capable of using plane waves as the incident signal,to perform optical logic operations via a diffractive neural network.Physically,the incident plane wave is first spatially encoded by a specific logic operation at the input layer and further decoded through the hidden layers,namely,a compound Huygens’metasurface.That is,the judiciously designed metasurface scatters the encoded light into one of two small designated areas at the output layer,which provides the information of output logic states.Importantly,after training of the diffractive neural network,all seven basic types of optical logic operations can be realized by the same metasurface.As a conceptual illustration,three logic operations(NOT,OR,and AND)are experimentally demonstrated at microwave frequencies.
基金sponsored by the National Natural Science Foundation of China (61625502, 11961141010, 61975176, and U19A2054)the Top-Notch Young Talents Program of China+1 种基金the Fundamental Research Funds for the Central Universitiessponsored by Singapore Ministry of Education under Grant Nos. MOE2018-T2-1-022 (S), MOE2015-T2-1-070, MOE2016-T3-1-006, and Tier 1 RG174/16 (S)
文摘Recent advances in non-radiative wireless power transfer(WPT)technique essentially relying on magnetic resonance and near-field coupling have successfully enabled a wide range of applications.However,WPT systems based on double resonators are severely limited to short-or mid-range distance,due to the deteriorating efficiency and power with long transfer distance.WPT systems based on multi-relay resonators can overcome this problem,which,however,suffer from sensitivity to perturbations and fabrication imperfections.Here,we experimentally demonstrate a concept of topological wireless power transfer(TWPT),where energy is transferred efficiently via the near-field coupling between two topological edge states localized at the ends of a one-dimensional radiowave topological insulator.Such a TWPT system can be modelled as a parity-time-symmetric Su-Schrieffer-Heeger(SSH)chain with complex boundary potentials.Besides,the coil configurations are judiciously designed,which significantly suppress the unwanted cross-couplings between nonadjacent coils that could break the chiral symmetry of the SSH chain.By tuning the inter-and intra-cell coupling strengths,we theoretically and experimentally demonstrate high energy transfer efficiency near the exceptional point of the topological edge states,even in the presence of disorder.The combination of topological metamaterials,non-Hermitian physics,and WPT techniques could promise a variety of robust,efficient WPT applications over long distances in electronics,transportation,and industry.
基金sponsored by the Key Research and Development Program of the Ministry of Science and Technology under Grants No.2022YFA1404704,2022YFA1404902,2022YFA1405200the National Natural Science Foundation of China(NNSFC)under Grants No.11961141010,No.61975176,the Top-Notch Young Talents Program of China and the Fundamental Research Funds for the Central Universities.
文摘Recent breakthroughs in deep learning have ushered in an essential tool for optics and photonics,recurring in various applications of material design,system optimization,and automation control.Deep learning-enabled on-demand metasurface design has been the subject of extensive expansion,as it can alleviate the time-consuming,low-efficiency,and experience-orientated shortcomings in conventional numerical simulations and physics-based methods.However,collecting samples and training neural networks are fundamentally confined to predefined individual metamaterials and tend to fail for large problem sizes.Inspired by object-oriented C++programming,we propose a knowledge-inherited paradigm for multi-object and shape-unbound metasurface inverse design.Each inherited neural network carries knowledge from the"parent"metasurface and then is freely assembled to construct the"offspring"metasurface;such a process is as simple as building a container-type house.We benchmark the paradigm by the free design of aperiodic and periodic metasurfaces,with accuracies that reach 86.7%.Furthermore,we present an intelligent origami metasurface to facilitate compatible and lightweight satellite communication facilities.Our work opens up a new avenue for automatic metasurface design and leverages the assemblability to broaden the adaptability of intelligent metadevices.
基金National Natural Science Foundation of China(11961141010,61625502,61975176,61975182,62071424)Top-Notch Young Talents Program of ChinaFundamental Research Funds for the Central Universities。
文摘Being invisible at will has been a long-standing dream for centuries, epitomized by numerous legends;humans have never stopped their exploration steps to realize this dream. Recent years have witnessed a breakthrough in this search due to the advent of transformation optics, metamaterials, and metasurfaces. However, the previous metasurface cloaks typically work in a reflection manner that relies on a high-reflection background, thus limiting the applications. Here, we propose an easy yet viable approach to realize the transmitted metasurface cloak, just composed of two planar metasurfaces to hide an object inside, such as a cat. To tackle the hard-to-converge issue caused by the nonuniqueness phenomenon, we deploy a tandem neural network(T-NN) to efficiently streamline the inverse design. Once pretrained, the T-NN can work for a customer-desired electromagnetic response in one single forward computation, saving a great amount of time. Our work opens a new avenue to realize a transparent invisibility cloak, and the tandem-NN can also inspire the inverse design of other metamaterials and photonics.
