Soft biological tissues are challenging materials for both testing and modeling.Despite the development of many constitutive models,the processing of choosing the most suitable model remains heuristic,relying signific...Soft biological tissues are challenging materials for both testing and modeling.Despite the development of many constitutive models,the processing of choosing the most suitable model remains heuristic,relying significantly on personal experience and preference.Another issue is that the amount of collected experimental data is always finite.In this study,we trained a constitutive artificial neural network based on experimental data of cattle skeletal muscle tissue for the self-directed auto-discovery of constitutive models.The discovered models inherently satisfy thermodynamic consistency,material objectivity,polyconvexity,and necessary physical restrictions.Two constitutive models have been discovered by the trained neural network.Considering the constraints of finite experimental data,the generality and reliability of the auto-discovered con-stitutive models remain to be analyzed.Through experimental data of pig skeletal muscle tissue,we assess the goodness-of-fit and parameter identifiability of the automatically discovered constitutive models.At first glance,both auto-discovered models have excellent prediction accuracy.Further exploration from the perspective of information geometry suggests that one of the auto-discovered models is superior to the other in terms of parameter identifiability.The findings of the current work are expected to extend our understanding of auto-discovered constitutive models and offer a new perspective to advance machine learning-driven mechanics.展开更多
Pore formation is a significant challenges in the advancement of laser additive manufacturing(LAM)technologies.To address this issue,image data-driven pore detection techniques have become a research focus.However,exi...Pore formation is a significant challenges in the advancement of laser additive manufacturing(LAM)technologies.To address this issue,image data-driven pore detection techniques have become a research focus.However,existing methods are constrained by reliance on a single detection environment(e.g.,consistent brightness)and fixed input image sizes,limiting their predictive accuracy and application scope.This paper introduces an in-novative a pore detection method based on a deep learning model for laser-directed energy deposition(L-DED).The proposed method leverages the deep learning model’s ability to extract feature information from melt pool images captured by a high-speed camera,enabling efficient pore detection under varying brightness conditions and diverse image sizes.The detection results demonstrate that,under varying brightness levels,the proposed model achieves a pore detection accuracy of approximately 93.5% and a root mean square error(RMSE)of 0.42 for local porosity prediction.Additionally,even with changes in input image size,the model maintains robust performance,achieving a detection accuracy of 96% for pore status detection and an RMSE value of 0.09 for local porosity prediction.This study not only addresses the limitations of traditional detection techniques but also broadens the scope of online detection technologies.It highlights the potential of deep learning in complex industrial settings and provides valuable insights for advancing defect detection research in related fields.展开更多
Lithography is a Key enabling technique in modern micro/nano scale technology.Achieving the optimal trade-off between resolution,throughput,and cost remains a central focus in the ongoing development.However,current l...Lithography is a Key enabling technique in modern micro/nano scale technology.Achieving the optimal trade-off between resolution,throughput,and cost remains a central focus in the ongoing development.However,current lithographic techniques such as direct-write,projection,and extreme ultraviolet lithography achieve higher resolution at the expense of increased complexity in optical systems or the use of shorter-wavelength light sources,thus raising the overall cost of production.Here,we present a cost-effective and wafer-level perfect conformal contact lithography at the diffraction limit.By leveraging a transferable photoresist,the technique ensures optimal contact between the mask and photoresist with zero-gap,facilitating the transfer of patterns at the diffraction limit while maintaining high fidelity and uniformity across large wafers.This technique applies to a wide range of complex surfaces,including non-conductive glass surfaces,flexible substrates,and curved surfaces.The proposed technique expands the potential of contact photolithography for novel device architectures and practic al manufacturing processes.展开更多
Optical imaging systems have greatly extended human visual capabilities,enabling the observation and understanding of diverse phenomena.Imaging technologies span a broad spectrum of wavelengths from x-ray to radio fre...Optical imaging systems have greatly extended human visual capabilities,enabling the observation and understanding of diverse phenomena.Imaging technologies span a broad spectrum of wavelengths from x-ray to radio frequencies and impact research activities and our daily lives.Traditional glass lenses are fabricated through a series of complex processes,while polymers offer versatility and ease of production.However,modern applications often require complex lens assemblies,driving the need for miniaturization and advanced designs with micro-and nanoscale features to surpass the capabilities of traditional fabrication methods.Three-dimensional(3D)printing,or additive manufacturing,presents a solution to these challenges with benefits of rapid prototyping,customized geometries,and efficient production,particularly suited for miniaturized optical imaging devices.Various 3D printing methods have demonstrated advantages over traditional counterparts,yet challenges remain in achieving nanoscale resolutions.Two-photon polymerization lithography(TPL),a nanoscale 3D printing technique,enables the fabrication of intricate structures beyond the optical diffraction limit via the nonlinear process of two-photon absorption within liquid resin.It offers unprecedented abilities,e.g.alignment-free fabrication,micro-and nanoscale capabilities,and rapid prototyping of almost arbitrary complex 3D nanostructures.In this review,we emphasize the importance of the criteria for optical performance evaluation of imaging devices,discuss material properties relevant to TPL,fabrication techniques,and highlight the application of TPL in optical imaging.As the first panoramic review on this topic,it will equip researchers with foundational knowledge and recent advancements of TPL for imaging optics,promoting a deeper understanding of the field.By leveraging on its high-resolution capability,extensive material range,and true 3D processing,alongside advances in materials,fabrication,and design,we envisage disruptive solutions to current challenges and a promising incorporation of TPL in future optical imaging applications.展开更多
There is an urgent need for novel processes that can integrate different functional nanostructures onto specific substrates,so as to meet the fast-growing need for broad applications in nanoelectronics,nanophotonics,a...There is an urgent need for novel processes that can integrate different functional nanostructures onto specific substrates,so as to meet the fast-growing need for broad applications in nanoelectronics,nanophotonics,and fexible optoelectronics.Existing direct-lithography methods are difficult to use on fexible,nonplanar,and biocompatible surfaces.Therefore,this fabrication is usually accomplished by nanotransfer printing.However,large-scale integration of multiscale nanostructures with unconventional substrates remains challenging because fabrication yields and quality are often limited by the resolution,uniformity,adhesivity,and integrity of the nanostructures formed by direct transfer.Here,we proposed a resist-based transfer strategy enabled by near-zero adhesion,which was achieved by molecular modification to attain a critical surface energy interval.This approach enabled the intact transfer of wafer-scale,ultrathin-resist nanofilms onto arbitrary substrates with mitigated cracking and wrinkling,thereby facilitating the in situ fabrication of nanostructures for functional devices.Applying this approach,fabrication of three-dimensional-stacked multilayer structures with enhanced functionalities,nanoplasmonic structures with~10 nm resolution,and MoS2-based devices with excellent performance was demonstrated on specific substrates.These results collectively demonstrated the high stability,reliability,and throughput of our strategy for optical and electronic device applications.展开更多
Hard carbon (HC) has been considered as promising anode material for sodium-ion batteries (SIBs).The optimization of hard carbon’s microstructure and solid electrolyte interface (SEI) property are demonstrated effect...Hard carbon (HC) has been considered as promising anode material for sodium-ion batteries (SIBs).The optimization of hard carbon’s microstructure and solid electrolyte interface (SEI) property are demonstrated effective in enhancing the Na+storage capability,however,a one-step regulation strategy to achieve simultaneous multi-scale structures optimization is highly desirable.Herein,we have systematically investigated the effects of boron doping on hard carbon’s microstructure and interface chemistry.A variety of structure characterizations show that appropriate amount of boron doping can increase the size of closed pores via rearrangement of carbon layers with improved graphitization degree,which provides more Na+storage sites.In-situ Fourier transform infrared spectroscopy/electrochemical impedance spectroscopy (FTIR/EIS) and X-ray photoelectron spectroscopy (XPS) analysis demonstrate the presence of more BC3and less B–C–O structures that result in enhanced ion diffusion kinetics and the formation of inorganic rich and robust SEI,which leads to facilitated charge transfer and excellent rate performance.As a result,the hard carbon anode with optimized boron doping content exhibits enhanced rate and cycling performance.In general,this work unravels the critical role of boron doping in optimizing the pore structure,interface chemistry and diffusion kinetics of hard carbon,which enables rational design of sodium-ion battery anode with enhanced Na+storage performance.展开更多
Changes to the microstructure of a hard carbon(HC)and its solid electrolyte interface(SEI)can be effective in improving the electrode kinetics.However,achieving fast charging using a simple and inexpensive strategy wi...Changes to the microstructure of a hard carbon(HC)and its solid electrolyte interface(SEI)can be effective in improving the electrode kinetics.However,achieving fast charging using a simple and inexpensive strategy without sacrificing its initial Coulombic efficiency remains a challenge in sodium ion batteries.A simple liquid-phase coating approach has been used to generate a pitch-derived soft carbon layer on the HC surface,and its effect on the porosity of HC and SEI chemistry has been studied.A variety of structural characterizations show a soft carbon coating can increase the defect and ultra-micropore contents.The increase in ultra-micropore comes from both the soft carbon coatings and the larger pores within the HC that are partially filled by pitch,which provides more Na+storage sites.In-situ FTIR/EIS and ex-situ XPS showed that the soft carbon coating induced the formation of thinner SEI that is richer in NaF from the electrolyte,which stabilized the interface and promoted the charge transfer process.As a result,the anode produced fastcharging(329.8 mAh g^(−1)at 30 mA g^(−1)and 198.6 mAh g^(−1)at 300 mA g^(−1))and had a better cycling performance(a high capacity retention of 81.4%after 100 cycles at 150 mA g^(−1)).This work reveals the critical role of coating layer in changing the pore structure,SEI chemistry and diffusion kinetics of hard carbon,which enables rational design of sodium-ion battery anode with enhanced fast charging capability.展开更多
Metal micro-nano grating has received much attention due to its ability to provide high-efficiency light absorption.However,the current research scales of these metal gratings are focused on subwavelengths,and little ...Metal micro-nano grating has received much attention due to its ability to provide high-efficiency light absorption.However,the current research scales of these metal gratings are focused on subwavelengths,and little attention has been paid to the absorption properties of metal gratings at other scales.We investigate the absorption properties of metal gratings based on surface plasmon resonance(SPR)across the scales from superwavelength to subwavelength.Under grazing incidence,we observe continuous strong absorption phenomena from superwavelength to subwavelength Al triangle-groove gratings(TGGs).Perfect absorption is realized at the subwavelength scale,whereas the maximum absorption at all other scales exceeds 74%.The electric field distribution gives the mechanism of the strong absorption phenomenon attributed to SPR on the surface of Al TGGs at different scales.In particular,subwavelength Al TGGs have perfectly symmetric absorption properties for different blaze angles,and the symmetry is gradually broken as the grating period’s scale increases.Furthermore,taking Al gratings with varying groove shapes for example,we extend the equivalence rule of grating grooves to subwavelength from near-wavelength and explain the symmetric absorption properties in Al TGGs.We unify the research of metal grating absorbers outside the subwavelength scale to a certain extent,and these findings also open new perspectives for the design of metal gratings in the future.展开更多
A finite-time adaptive sliding mode controller is designed to improve the trajectory tracking capability of a quadrotor unmanned aerial vehicle(UAV)in the presence of model uncertainties and unmodeled external disturb...A finite-time adaptive sliding mode controller is designed to improve the trajectory tracking capability of a quadrotor unmanned aerial vehicle(UAV)in the presence of model uncertainties and unmodeled external disturbances.By applying adaptive nonsingular fast terminal sliding mode control(ANFTSMC)to the quadrotor UAV system,rapid response,finite-time convergence,and high-precision steady-state control are achieved under uncertainties and external disturbances,while also avoiding singularities and reducing the effect of chattering.Furthermore,the adaptive strategy is designed to estimate the upper bounds of model uncertainties and external disturbances without requiring prior bounded information.The finite-time convergence capability of the system is rigorously analyzed using the Lyapunov stability framework.Extensive simulation studies and experimental validations collectively demonstrate the efficacy of the designed control scheme.Notably,stable flight in the presence of wind disturbances and control of the contact force in experiments with wind turbine blades underscore the applicability of the strategy for achieving reliable quadrotor UAV operations in complex environments.展开更多
The strong connection between braids and knots provides valuable insights into studying the topological state and phase classification of various physical systems.The phenomenon of non-Hermitian(NH)two-and three-band ...The strong connection between braids and knots provides valuable insights into studying the topological state and phase classification of various physical systems.The phenomenon of non-Hermitian(NH)two-and three-band braiding has received widespread attention.However,a systematic exploration and visualization of non-Abelian braiding and the associated knot transformations in four-band systems remains unexplored.Here,we propose a theoretical model of NH four-band braiding,provide its phase diagram,and establish its trivial,Abelian,and non-Abelian braiding rules.Additionally,we report on special knots,such as the Hopf and Solomon links in braided knots,and reveal that their transformations are accompanied by and mediated through exceptional points.Our work provides a detailed case for studying NH multiband braiding and knot structures in four-band systems,which could offer insights for topological photonics and analog information processing applications.展开更多
In this paper,a novel data-driven bipartite consensus control scheme is proposed for the rotation problem of large workpieces with multi-robot systems(MRSs)under a directed communication topology.The rotation of a lar...In this paper,a novel data-driven bipartite consensus control scheme is proposed for the rotation problem of large workpieces with multi-robot systems(MRSs)under a directed communication topology.The rotation of a large workpiece is described as the MRSs with cooperation and antagonism interaction.By the signed graph theory,it is further transformed into a bipartite consensus control problem,where all followers are uniformly degenerated into the general nonlinear systems based on the lateral error model.To augment the flexibility of control protocol and improve control performance,a higher-dimensional full form dynamic linearization(FFDL)technique is committed to the MRSs.The control input criterion function consists of the data model based on FFDL and the bipartite consensus error based on the signed graph theory,and the proposed control protocol is given by optimizing this criterion function.In this way,this scheme has a higher degree of freedom and better adaptive adjustment capability while not excessively increasing the control method complexity,and it can also be compatible with other forms of dynamic linearization techniques in MRSs.Further,three matrix norm lemmas are introduced to deal with the challenges of stability analysis caused by higher matrix dimensions and more robots.Finally,the effectiveness of the proposed method is verified by numerical simulations.展开更多
Hybrid skin-topological effect(HSTE)in non-Hermitian systems exhibits both the skin effect and topological protection,offering a novel mechanism for localization of topological edge states(TESs)in electrons,circuits,a...Hybrid skin-topological effect(HSTE)in non-Hermitian systems exhibits both the skin effect and topological protection,offering a novel mechanism for localization of topological edge states(TESs)in electrons,circuits,and photons.However,it remains unclear whether the HSTE can be realized in quasicrystals.展开更多
We have introduced a new approach to calculate the orbital angular momentum(OAM)of bound states in continuum(BICs)and below-continuum-resonance(BCR)modes in the rotational periodic system nested inside and outside by ...We have introduced a new approach to calculate the orbital angular momentum(OAM)of bound states in continuum(BICs)and below-continuum-resonance(BCR)modes in the rotational periodic system nested inside and outside by transforming the Bloch wave number from the translational periodic system.We extensively classify and study these BICs and BCR modes,which exhibit high-quality(high-Q)factors,in different regions relative to the interface of the system.These BICs and BCR modes with a high-Q factor have been studied in detail based on distinctive structural parameters and scattering theory.The outcomes of this research break the periodic limitation of interface state-based BICs,and realize more and higher symmetry interface state-based BICs and BCR modes.Moreover,we can control the region where light is captured by adjusting the frequency,and show that the Q factor of BICs is more closely related to the ordinal number of rings and the rotational symmetry number of the system.展开更多
Ruthenium(Ru)is a promising electrocatalyst for hydrogen oxidation reaction(HOR)due to the similar metal hydrogen bond energy to Pt.However,Ru is easily deactivated or dissolved under an oxidation potential,which make...Ruthenium(Ru)is a promising electrocatalyst for hydrogen oxidation reaction(HOR)due to the similar metal hydrogen bond energy to Pt.However,Ru is easily deactivated or dissolved under an oxidation potential,which makes it unavailable in proton exchange membrane fuel cells.In this work,ultrastable Ru-based electrocatalysts for HOR in high-temperature polymer electrolyte membrane fuel cells(HTPEMFCs)were developed by Mo doping.Under the operation conditions of HT-PEMFCs,thermal reduction inhibited the production of amorphous Ru oxide(RuO_(2))in the Ru-based electrocatalysts during the HOR.Mo doping significantly improved the stability of the electrocatalyst by decreasing the reduction temperature of RuO_(2)and accelerating the HOR by reducing the adsorption of H*.RuMo/C exhibited excellent HOR activity at high temperatures due to thermal reduction inhibition of electrooxidation;the fabricated HT-PEMFCs exhibited long-term stability and a 1050 mW cm^(−2)peak power density,comparable to the commercial Pt catalyst.This work provides a novel strategy for designing electrocatalysts by combining material intrinsic properties and work conditions,which could promote the development of advanced electrocatalysts for HT-PEMFCs.展开更多
The plant defense hormone jasmonates not only play important roles in plant growth,development,and resistance,but also hold promise for bringing new strategies in plant protection and cancer therapy.Recently,de novo b...The plant defense hormone jasmonates not only play important roles in plant growth,development,and resistance,but also hold promise for bringing new strategies in plant protection and cancer therapy.Recently,de novo biosynthesis of natural and unnatural jasmonates in refactored yeast with integration of 15 heterologous genes and 3 native genes deleted was reported.Here,we highlight the feasible and sustainable platform to efficiently produce jasmonates,which would benefit both agriculture and human health.展开更多
In the paper,a reduced basis(RB)method for time-dependent nonlocal problems with a special parameterized fractional Laplace kernel function is proposed.Because of the lack of sparsity of discretized nonlocal systems c...In the paper,a reduced basis(RB)method for time-dependent nonlocal problems with a special parameterized fractional Laplace kernel function is proposed.Because of the lack of sparsity of discretized nonlocal systems compared to corresponding local partial differential equation(PDE)systems,model reduction for nonlocal systems becomes more critical.The method of snapshots and greedy(MOS-greedy)algorithm of RB method is developed for nonlocal problems with random inputs,which provides an efficient and reliable approximation of the solution.A major challenge lies in the excessive influence of the time domain on the model reduction process.To address this,the Fourier transform is applied to convert the original time-dependent parabolic equation into a frequency-dependent elliptic equation,where variable frequencies are independent.This enables parallel computation for approximating the solution in the frequency domain.Finally,the proposed MOS-greedy algorithm is applied to the nonlocal diffusion problems.Numerical results demonstrate that it provides an accurate approximation of the full order problems and significantly improves computational efficiency.展开更多
Flexible photodetector(PD)arrays have the potential to replace the rods and cones in the retina,converting external light signals into electrical signals and offering hope for blind patients to regain vision.However,i...Flexible photodetector(PD)arrays have the potential to replace the rods and cones in the retina,converting external light signals into electrical signals and offering hope for blind patients to regain vision.However,issues like discontinuous electrode surfaces and incompletely crystallized perovskites can cause cracks and degrade the performance of flexible PDs during repeated bending,hindering their development and applications.In this study,we employ a combination of radio frequency magnetron sputtering and angular ion beam polishing to achieve an ultrathin,ultrasmooth platinum(Pt)electrode film(UTPF)with a thickness of less than 10 nm.Building on this,a vapor deposition method with dynamically regulated evaporation rates is developed to obtain a dense-gradient PbI_(2)precursor.This funnel-shaped vertical structure precursor facilitates the penetration of CH_(3)NH_(3)I solution,ultimately resulting in a dense and uniform perovskite film with large grains and strong interfacial bonding with UTPF.The results indicate that the flexible PD arrays exhibit excellent optoelectronic performances,characterized by high sensitivity,detectivity and a large on/off current ratio.Furthermore,benefitting from their exceptional flexibility and electrical stability,the devices retain 92.53%of the original photocurrent after 4000 bending cycles at large angles.Notably,the integrated 10×10 flexible PD arrays demonstrate good uniformity in dark current and photocurrent,along with high imaging resolution,showing the reliable imaging capabilities of the flexible arrays and their potential applications in artificial retina.展开更多
Prussian blue analogues(PBAs)are increasingly recognized as promising cathode materials for potassium-ion batteries(PIBs)owing to their low cost,distinctive open structure,and high theoretical capacity.However,PBAs st...Prussian blue analogues(PBAs)are increasingly recognized as promising cathode materials for potassium-ion batteries(PIBs)owing to their low cost,distinctive open structure,and high theoretical capacity.However,PBAs still face challenges related to low crystallinity and elevated crystal water content,adversely affecting their performance as cathodes.This study proposes a straightforward low-temperature synthesis method for PBAs termed cryo-synthesized PBAs.The nucleation and growth processes were effectively slowed down by precisely controlling the synthesis temperature.This approach successfully yields PBAs with enhanced crystallinity and uniform particle size.The PBA electrode utilized as the cathode in PIBs demonstrates remarkable long-term cycling stability over 10,000 cycles at a current density of 2000 mA g^(-1).We believe these findings will promote the widespread adoption of PBAs in aqueous PIBs,paving the way for large-scale,cost-effective applications.展开更多
The poor electronic conductivity of conversion-type materials(CMs)and the dissolution/diffusion loss of transition metal(TM)ions in electrodes seriously hinder the practical applications of potassium ion batteries.Sim...The poor electronic conductivity of conversion-type materials(CMs)and the dissolution/diffusion loss of transition metal(TM)ions in electrodes seriously hinder the practical applications of potassium ion batteries.Simply optimizing the electrode materials or designing the electrode components is no longer effective in improving the performance of CMs.Binders,as one of the elec-trode components,play a vital role in improving the electrochemical per-formance of batteries.Here we rationally designed FeF_(2) electrodes for the first time by optimizing electrode materials with the introduction of carbon na-notubes(CNTs)and combined with a sodium alginate(SA)binder based on strong interactions.We show that the FeF_(2)@CNTs-SA cathode does not suffer from TM ion dissolution and delivers a high capacity of 184.7 mAh g^(-1) at 10 mA g^(-1).Moreover,the capacity of FeF_(2)@CNTs-SA is as high as 99.2 mAh g^(-1) after 100 cycles at 100 mA g^(-1),which is a twofold increase compared to FeF_(2)@CNTs-PVDF.After calculating the average capacity decay rate per cycle of them,we find that FeF_(2)@CNTs-SA is about one-third lower than FeF_(2)@CNTs-PVDF.Therefore,the SA binder can be broadly used for electrodes comprising several CMs,providing meaningful insights into mechanisms that lead to their improved electrochemical performances.展开更多
Islanded microgrids(IMGs)offer a viable and efficient energy self-sustaining solution for distributed resources in remote areas.While without utility grid support,the frequency of IMG is susceptible to mismatches betw...Islanded microgrids(IMGs)offer a viable and efficient energy self-sustaining solution for distributed resources in remote areas.While without utility grid support,the frequency of IMG is susceptible to mismatches between demand and generation.Moreover,IMGs encounter uncertain and nonlinear load disturbances together with system parameter perturbation,which further compromises frequency stability.To this aim,this paper proposes a robust multi-virtual synchronous generators(multi-VSGs)coordinated control strategy for distributed secondary frequency regulation(DSFR)in IMGs,which exhibits minimal model dependency and avoids reliance on global information.Two critical methods are developed:(1)a robust VSG control framework that incorporates the linear active disturbance rejection control(LADRC)technique,which enables the estimation and effective elimination of uncertain load disturbances and system's parameter perturbations;(2)a novel secondorder consensus algorithm-based control law for robust secondary frequency regulation,which is featured with proper power sharing among different participants,suppressed power oscillation caused by response disparities,and reduced reliance on complex communication system.Building on methods(1)and(2),a novel multi-VSGs coordinated control strategy is proposed,providing a robust solution for IMG's frequency restoration,and its dynamic characteristics are explored in detail.The correctness and effectiveness of the proposal are verified by both simulation and the hardware-in-the-loop(HIL)experiment results across typical scenarios.展开更多
基金supported by the National Natural Science Foundation of China(NNSFC)(Grant Nos.12272132 and 11922206).
文摘Soft biological tissues are challenging materials for both testing and modeling.Despite the development of many constitutive models,the processing of choosing the most suitable model remains heuristic,relying significantly on personal experience and preference.Another issue is that the amount of collected experimental data is always finite.In this study,we trained a constitutive artificial neural network based on experimental data of cattle skeletal muscle tissue for the self-directed auto-discovery of constitutive models.The discovered models inherently satisfy thermodynamic consistency,material objectivity,polyconvexity,and necessary physical restrictions.Two constitutive models have been discovered by the trained neural network.Considering the constraints of finite experimental data,the generality and reliability of the auto-discovered con-stitutive models remain to be analyzed.Through experimental data of pig skeletal muscle tissue,we assess the goodness-of-fit and parameter identifiability of the automatically discovered constitutive models.At first glance,both auto-discovered models have excellent prediction accuracy.Further exploration from the perspective of information geometry suggests that one of the auto-discovered models is superior to the other in terms of parameter identifiability.The findings of the current work are expected to extend our understanding of auto-discovered constitutive models and offer a new perspective to advance machine learning-driven mechanics.
基金supported by National Natural Science Foundation of China(Grant No.52475155)National Science Foundation for Hunan Province,China(Grant No.2023JJ30137)+2 种基金Guangdong Basic and Applied Basic Research Foundation(Grant No.2024A1515010684)Guangdong Basic and Applied Basic Research Foundation(Grant No.2023A1515240059)Program sponsored by the Foundation of Yuelushan Center for Industrial Innovation(Grant No.2023YCII0138).
文摘Pore formation is a significant challenges in the advancement of laser additive manufacturing(LAM)technologies.To address this issue,image data-driven pore detection techniques have become a research focus.However,existing methods are constrained by reliance on a single detection environment(e.g.,consistent brightness)and fixed input image sizes,limiting their predictive accuracy and application scope.This paper introduces an in-novative a pore detection method based on a deep learning model for laser-directed energy deposition(L-DED).The proposed method leverages the deep learning model’s ability to extract feature information from melt pool images captured by a high-speed camera,enabling efficient pore detection under varying brightness conditions and diverse image sizes.The detection results demonstrate that,under varying brightness levels,the proposed model achieves a pore detection accuracy of approximately 93.5% and a root mean square error(RMSE)of 0.42 for local porosity prediction.Additionally,even with changes in input image size,the model maintains robust performance,achieving a detection accuracy of 96% for pore status detection and an RMSE value of 0.09 for local porosity prediction.This study not only addresses the limitations of traditional detection techniques but also broadens the scope of online detection technologies.It highlights the potential of deep learning in complex industrial settings and provides valuable insights for advancing defect detection research in related fields.
基金supported by the National Key Research and Development Program of China (2022YFB4602600)National Natural Science Foundation of China (Grant Nos. 52425508 & 52221001)the Hunan Provincial Natural Science Foundation of China (2025JJ60286)。
文摘Lithography is a Key enabling technique in modern micro/nano scale technology.Achieving the optimal trade-off between resolution,throughput,and cost remains a central focus in the ongoing development.However,current lithographic techniques such as direct-write,projection,and extreme ultraviolet lithography achieve higher resolution at the expense of increased complexity in optical systems or the use of shorter-wavelength light sources,thus raising the overall cost of production.Here,we present a cost-effective and wafer-level perfect conformal contact lithography at the diffraction limit.By leveraging a transferable photoresist,the technique ensures optimal contact between the mask and photoresist with zero-gap,facilitating the transfer of patterns at the diffraction limit while maintaining high fidelity and uniformity across large wafers.This technique applies to a wide range of complex surfaces,including non-conductive glass surfaces,flexible substrates,and curved surfaces.The proposed technique expands the potential of contact photolithography for novel device architectures and practic al manufacturing processes.
基金support from the National Research Foundation (NRF) Singapore, under its Competitive Research Programme Award NRF-CRP20-20170004 and NRF Investigatorship Award NRF-NRFI06-20200005MTC Programmatic Grant M21J9b0085, as well as the Lite-On Project RS-INDUS-00090+5 种基金support from Australian Research Council (DE220101085, DP220102152)grants from German Research Foundation (SCHM2655/15-1, SCHM2655/21-1)Lee-Lucas Chair in Physics and funding by the Australian Research Council DP220102152financial support from the National Natural Science Foundation of China (Grant No. 62275078)Natural Science Foundation of Hunan Province of China (Grant No. 2022JJ20020)Shenzhen Science and Technology Program (Grant No. JCYJ20220530160405013)
文摘Optical imaging systems have greatly extended human visual capabilities,enabling the observation and understanding of diverse phenomena.Imaging technologies span a broad spectrum of wavelengths from x-ray to radio frequencies and impact research activities and our daily lives.Traditional glass lenses are fabricated through a series of complex processes,while polymers offer versatility and ease of production.However,modern applications often require complex lens assemblies,driving the need for miniaturization and advanced designs with micro-and nanoscale features to surpass the capabilities of traditional fabrication methods.Three-dimensional(3D)printing,or additive manufacturing,presents a solution to these challenges with benefits of rapid prototyping,customized geometries,and efficient production,particularly suited for miniaturized optical imaging devices.Various 3D printing methods have demonstrated advantages over traditional counterparts,yet challenges remain in achieving nanoscale resolutions.Two-photon polymerization lithography(TPL),a nanoscale 3D printing technique,enables the fabrication of intricate structures beyond the optical diffraction limit via the nonlinear process of two-photon absorption within liquid resin.It offers unprecedented abilities,e.g.alignment-free fabrication,micro-and nanoscale capabilities,and rapid prototyping of almost arbitrary complex 3D nanostructures.In this review,we emphasize the importance of the criteria for optical performance evaluation of imaging devices,discuss material properties relevant to TPL,fabrication techniques,and highlight the application of TPL in optical imaging.As the first panoramic review on this topic,it will equip researchers with foundational knowledge and recent advancements of TPL for imaging optics,promoting a deeper understanding of the field.By leveraging on its high-resolution capability,extensive material range,and true 3D processing,alongside advances in materials,fabrication,and design,we envisage disruptive solutions to current challenges and a promising incorporation of TPL in future optical imaging applications.
基金supported by the National Key Research and Development Program of China(No.2022YFB4602600)the National Natural Science Foundation of China(No.52221001)Hunan Provincial Innovation Foundation for Postgraduate(No.CX20220406)。
文摘There is an urgent need for novel processes that can integrate different functional nanostructures onto specific substrates,so as to meet the fast-growing need for broad applications in nanoelectronics,nanophotonics,and fexible optoelectronics.Existing direct-lithography methods are difficult to use on fexible,nonplanar,and biocompatible surfaces.Therefore,this fabrication is usually accomplished by nanotransfer printing.However,large-scale integration of multiscale nanostructures with unconventional substrates remains challenging because fabrication yields and quality are often limited by the resolution,uniformity,adhesivity,and integrity of the nanostructures formed by direct transfer.Here,we proposed a resist-based transfer strategy enabled by near-zero adhesion,which was achieved by molecular modification to attain a critical surface energy interval.This approach enabled the intact transfer of wafer-scale,ultrathin-resist nanofilms onto arbitrary substrates with mitigated cracking and wrinkling,thereby facilitating the in situ fabrication of nanostructures for functional devices.Applying this approach,fabrication of three-dimensional-stacked multilayer structures with enhanced functionalities,nanoplasmonic structures with~10 nm resolution,and MoS2-based devices with excellent performance was demonstrated on specific substrates.These results collectively demonstrated the high stability,reliability,and throughput of our strategy for optical and electronic device applications.
基金National Key Research and Development Program of China (2022YFE0206300)National Natural Science Foundation of China (U21A2081,22075074, 22209047)+3 种基金Guangdong Basic and Applied Basic Research Foundation (2024A1515011620)Hunan Provincial Natural Science Foundation of China (2024JJ5068)Foundation of Yuelushan Center for Industrial Innovation (2023YCII0119)Student Innovation Training Program (S202410532594,S202410532357)。
文摘Hard carbon (HC) has been considered as promising anode material for sodium-ion batteries (SIBs).The optimization of hard carbon’s microstructure and solid electrolyte interface (SEI) property are demonstrated effective in enhancing the Na+storage capability,however,a one-step regulation strategy to achieve simultaneous multi-scale structures optimization is highly desirable.Herein,we have systematically investigated the effects of boron doping on hard carbon’s microstructure and interface chemistry.A variety of structure characterizations show that appropriate amount of boron doping can increase the size of closed pores via rearrangement of carbon layers with improved graphitization degree,which provides more Na+storage sites.In-situ Fourier transform infrared spectroscopy/electrochemical impedance spectroscopy (FTIR/EIS) and X-ray photoelectron spectroscopy (XPS) analysis demonstrate the presence of more BC3and less B–C–O structures that result in enhanced ion diffusion kinetics and the formation of inorganic rich and robust SEI,which leads to facilitated charge transfer and excellent rate performance.As a result,the hard carbon anode with optimized boron doping content exhibits enhanced rate and cycling performance.In general,this work unravels the critical role of boron doping in optimizing the pore structure,interface chemistry and diffusion kinetics of hard carbon,which enables rational design of sodium-ion battery anode with enhanced Na+storage performance.
基金National Key Research and Development Program of China(2022YFE0206300)National Natural Science Foundation of China(U21A2081,22075074,22209047)+2 种基金Guangdong Basic and Applied Basic Research Foundation(2024A1515011620)Hunan Provincial Natural Science Foundation of China(2024JJ5068)Foundation of Yuelushan Center for Industrial Innovation(2023YCII0119)。
文摘Changes to the microstructure of a hard carbon(HC)and its solid electrolyte interface(SEI)can be effective in improving the electrode kinetics.However,achieving fast charging using a simple and inexpensive strategy without sacrificing its initial Coulombic efficiency remains a challenge in sodium ion batteries.A simple liquid-phase coating approach has been used to generate a pitch-derived soft carbon layer on the HC surface,and its effect on the porosity of HC and SEI chemistry has been studied.A variety of structural characterizations show a soft carbon coating can increase the defect and ultra-micropore contents.The increase in ultra-micropore comes from both the soft carbon coatings and the larger pores within the HC that are partially filled by pitch,which provides more Na+storage sites.In-situ FTIR/EIS and ex-situ XPS showed that the soft carbon coating induced the formation of thinner SEI that is richer in NaF from the electrolyte,which stabilized the interface and promoted the charge transfer process.As a result,the anode produced fastcharging(329.8 mAh g^(−1)at 30 mA g^(−1)and 198.6 mAh g^(−1)at 300 mA g^(−1))and had a better cycling performance(a high capacity retention of 81.4%after 100 cycles at 150 mA g^(−1)).This work reveals the critical role of coating layer in changing the pore structure,SEI chemistry and diffusion kinetics of hard carbon,which enables rational design of sodium-ion battery anode with enhanced fast charging capability.
基金upported by the Guangdong Provincial Pearl River Talents Program(Grant No.2019ZT08Z779)the National Natural Science Foundation of China(Grant Nos.U21A20509 and 62205124).
文摘Metal micro-nano grating has received much attention due to its ability to provide high-efficiency light absorption.However,the current research scales of these metal gratings are focused on subwavelengths,and little attention has been paid to the absorption properties of metal gratings at other scales.We investigate the absorption properties of metal gratings based on surface plasmon resonance(SPR)across the scales from superwavelength to subwavelength.Under grazing incidence,we observe continuous strong absorption phenomena from superwavelength to subwavelength Al triangle-groove gratings(TGGs).Perfect absorption is realized at the subwavelength scale,whereas the maximum absorption at all other scales exceeds 74%.The electric field distribution gives the mechanism of the strong absorption phenomenon attributed to SPR on the surface of Al TGGs at different scales.In particular,subwavelength Al TGGs have perfectly symmetric absorption properties for different blaze angles,and the symmetry is gradually broken as the grating period’s scale increases.Furthermore,taking Al gratings with varying groove shapes for example,we extend the equivalence rule of grating grooves to subwavelength from near-wavelength and explain the symmetric absorption properties in Al TGGs.We unify the research of metal grating absorbers outside the subwavelength scale to a certain extent,and these findings also open new perspectives for the design of metal gratings in the future.
基金supported by the Guangdong Province Basic and Applied Basic Research Fund Project(Grant No.2024A1515240062)the Key R&D Program of Jiangxi Province(Grant No.20243BBG71017)+1 种基金the National Natural Science Foundation of China(Grant No.62463020)the Teaching Reform Project of Changsha University of Science and Technology(Grant No.XJG24-048)。
文摘A finite-time adaptive sliding mode controller is designed to improve the trajectory tracking capability of a quadrotor unmanned aerial vehicle(UAV)in the presence of model uncertainties and unmodeled external disturbances.By applying adaptive nonsingular fast terminal sliding mode control(ANFTSMC)to the quadrotor UAV system,rapid response,finite-time convergence,and high-precision steady-state control are achieved under uncertainties and external disturbances,while also avoiding singularities and reducing the effect of chattering.Furthermore,the adaptive strategy is designed to estimate the upper bounds of model uncertainties and external disturbances without requiring prior bounded information.The finite-time convergence capability of the system is rigorously analyzed using the Lyapunov stability framework.Extensive simulation studies and experimental validations collectively demonstrate the efficacy of the designed control scheme.Notably,stable flight in the presence of wind disturbances and control of the contact force in experiments with wind turbine blades underscore the applicability of the strategy for achieving reliable quadrotor UAV operations in complex environments.
基金supported by the National Natural Science Foundation of China(Grant Nos.62575099,62075059,61405058)Guangdong Basic and Applied Basic Research Foundation(Grant No.2024A1515011353)+2 种基金Open Project of the State Key Laboratory of Advanced Optical Communication Systems and Networks of China(Grant No.2024GZKF20)the Natural Science Foundation of Hunan Province(Grant Nos.2020JJ4161 and 2017JJ2048)Scientific Research Foundation of Hunan Provincial Education Department(Grant No.21A0013)。
文摘The strong connection between braids and knots provides valuable insights into studying the topological state and phase classification of various physical systems.The phenomenon of non-Hermitian(NH)two-and three-band braiding has received widespread attention.However,a systematic exploration and visualization of non-Abelian braiding and the associated knot transformations in four-band systems remains unexplored.Here,we propose a theoretical model of NH four-band braiding,provide its phase diagram,and establish its trivial,Abelian,and non-Abelian braiding rules.Additionally,we report on special knots,such as the Hopf and Solomon links in braided knots,and reveal that their transformations are accompanied by and mediated through exceptional points.Our work provides a detailed case for studying NH multiband braiding and knot structures in four-band systems,which could offer insights for topological photonics and analog information processing applications.
基金supported in part by the National Natural Science Foundation of China(62473142,62203161)Special Funding Support for the Construction of Innovative Provinces in Hunan Province(2021GK1010)+1 种基金Guangdong Basic and Applied Basic Research Foundation(2024A1515011579),Project of State Key Laboratory of Advanced Design and Manufacturing Technology for Vehicle(72275007).
文摘In this paper,a novel data-driven bipartite consensus control scheme is proposed for the rotation problem of large workpieces with multi-robot systems(MRSs)under a directed communication topology.The rotation of a large workpiece is described as the MRSs with cooperation and antagonism interaction.By the signed graph theory,it is further transformed into a bipartite consensus control problem,where all followers are uniformly degenerated into the general nonlinear systems based on the lateral error model.To augment the flexibility of control protocol and improve control performance,a higher-dimensional full form dynamic linearization(FFDL)technique is committed to the MRSs.The control input criterion function consists of the data model based on FFDL and the bipartite consensus error based on the signed graph theory,and the proposed control protocol is given by optimizing this criterion function.In this way,this scheme has a higher degree of freedom and better adaptive adjustment capability while not excessively increasing the control method complexity,and it can also be compatible with other forms of dynamic linearization techniques in MRSs.Further,three matrix norm lemmas are introduced to deal with the challenges of stability analysis caused by higher matrix dimensions and more robots.Finally,the effectiveness of the proposed method is verified by numerical simulations.
基金supported by the National Natural Science Foundation of China(Grant Nos.61405058 and 62075059)the Natural Science Foundation of Hunan Province(Grant Nos.2017JJ2048 and 2020JJ4161)+2 种基金the Scientific Research Foundation of Hunan Provincial Education Department(Grant No.21A0013)the Open Project of the State Key Laboratory of Advanced Optical Communication Systems and Networks of China(Grant No.2024GZKF20)the Guangdong Basic and Applied Basic Research Foundation(Grant No.2024A1515011353)。
文摘Hybrid skin-topological effect(HSTE)in non-Hermitian systems exhibits both the skin effect and topological protection,offering a novel mechanism for localization of topological edge states(TESs)in electrons,circuits,and photons.However,it remains unclear whether the HSTE can be realized in quasicrystals.
基金supported by the National Natural Science Foundation of China (Grant Nos.61405058 and 62075059)the Natural Science Foundation of Hunan Province (Grant Nos.2017JJ2048 and 2020JJ4161)+2 种基金the Scientific Research Foundation of Hunan Provincial Education Department (Grant No.21A0013)the Open Project of State Key Laboratory of Advanced Optical Communication Systems and Networks of China (Grant No.2024GZKF20)the Guangdong Basic and Applied Basic Research Foundation (Grant No.2024A1515011353)。
文摘We have introduced a new approach to calculate the orbital angular momentum(OAM)of bound states in continuum(BICs)and below-continuum-resonance(BCR)modes in the rotational periodic system nested inside and outside by transforming the Bloch wave number from the translational periodic system.We extensively classify and study these BICs and BCR modes,which exhibit high-quality(high-Q)factors,in different regions relative to the interface of the system.These BICs and BCR modes with a high-Q factor have been studied in detail based on distinctive structural parameters and scattering theory.The outcomes of this research break the periodic limitation of interface state-based BICs,and realize more and higher symmetry interface state-based BICs and BCR modes.Moreover,we can control the region where light is captured by adjusting the frequency,and show that the Q factor of BICs is more closely related to the ordinal number of rings and the rotational symmetry number of the system.
基金The Top ten Technological Breakthrough Projects in Hunan Province(grant no.2023GK1050),the National Key R&D Program of China(grant no.2021YFA1500900)the National Natural Science Foundation of China(NSFC+9 种基金grant nos.22102053,21825201,22172047,and U19A2017)the Provincial Natural Science Foundation of Hunan,China(grant nos.2024JJ2012,2019GK2031,2016TP1009,2020JJ5045,and 2021JJ30089)the Science and Technology Innovation Program of Hunan Province,China(grant nos.2020RC2020 and 2022RC1036)Shenzhen Science and Technology Program,China(grant no.JCYJ20210324122209025)Changsha Municipal Natural Science Foundation,China(grant no.kq2007009)Changsha Municipal Natural Science Foundation,China(grant no.kq2007009)Basic and Applied Basic Research Foundation of Guangdong Province-Regional joint fund project,China(grant no.2021B1515120024)Guangdong Basic and Applied Basic Research Foundation,China(grant no.2024A1515012889)Shenzhen Science and Technology Program,China(grant no.JCYJ20210324122209025)Major Program of the Natural Science Foundation of Hunan Province,China(grant no.2021JC0006).
文摘Ruthenium(Ru)is a promising electrocatalyst for hydrogen oxidation reaction(HOR)due to the similar metal hydrogen bond energy to Pt.However,Ru is easily deactivated or dissolved under an oxidation potential,which makes it unavailable in proton exchange membrane fuel cells.In this work,ultrastable Ru-based electrocatalysts for HOR in high-temperature polymer electrolyte membrane fuel cells(HTPEMFCs)were developed by Mo doping.Under the operation conditions of HT-PEMFCs,thermal reduction inhibited the production of amorphous Ru oxide(RuO_(2))in the Ru-based electrocatalysts during the HOR.Mo doping significantly improved the stability of the electrocatalyst by decreasing the reduction temperature of RuO_(2)and accelerating the HOR by reducing the adsorption of H*.RuMo/C exhibited excellent HOR activity at high temperatures due to thermal reduction inhibition of electrooxidation;the fabricated HT-PEMFCs exhibited long-term stability and a 1050 mW cm^(−2)peak power density,comparable to the commercial Pt catalyst.This work provides a novel strategy for designing electrocatalysts by combining material intrinsic properties and work conditions,which could promote the development of advanced electrocatalysts for HT-PEMFCs.
基金the support from the National Key Research and Development Program of China(Nos.2021YFA1300400 and 2022YFF1002000)Shenzhen Science and Technology Innovation Commission(No.2021Szvup037)the Natural Science Foundation of Hunan Province(Nos.2022RC1015 and 2023RC1050).
文摘The plant defense hormone jasmonates not only play important roles in plant growth,development,and resistance,but also hold promise for bringing new strategies in plant protection and cancer therapy.Recently,de novo biosynthesis of natural and unnatural jasmonates in refactored yeast with integration of 15 heterologous genes and 3 native genes deleted was reported.Here,we highlight the feasible and sustainable platform to efficiently produce jasmonates,which would benefit both agriculture and human health.
基金supported by the Guangdong Basic and Applied Basic Research Foundation,China(Grant 2024A1515012548)supported by the National Natural Science Foundation of China(Grant 12401567)+1 种基金by the 2023 Guangzhou Basic and Applied Basic Research Project(Grant 2023A04J0035)by the Talent Special Projects of School-level Scientific Research Programs under Guangdong Poiytechnic Normal University(Grant 2022SDKYA025).
文摘In the paper,a reduced basis(RB)method for time-dependent nonlocal problems with a special parameterized fractional Laplace kernel function is proposed.Because of the lack of sparsity of discretized nonlocal systems compared to corresponding local partial differential equation(PDE)systems,model reduction for nonlocal systems becomes more critical.The method of snapshots and greedy(MOS-greedy)algorithm of RB method is developed for nonlocal problems with random inputs,which provides an efficient and reliable approximation of the solution.A major challenge lies in the excessive influence of the time domain on the model reduction process.To address this,the Fourier transform is applied to convert the original time-dependent parabolic equation into a frequency-dependent elliptic equation,where variable frequencies are independent.This enables parallel computation for approximating the solution in the frequency domain.Finally,the proposed MOS-greedy algorithm is applied to the nonlocal diffusion problems.Numerical results demonstrate that it provides an accurate approximation of the full order problems and significantly improves computational efficiency.
基金supported by the National Natural Science Foundation of China(62375081,U22A20138,52372146,62090035,52221001,and 52402181)the National Key R&D Program of China(2022YFA1204300 and 2022YFA1402501).
文摘Flexible photodetector(PD)arrays have the potential to replace the rods and cones in the retina,converting external light signals into electrical signals and offering hope for blind patients to regain vision.However,issues like discontinuous electrode surfaces and incompletely crystallized perovskites can cause cracks and degrade the performance of flexible PDs during repeated bending,hindering their development and applications.In this study,we employ a combination of radio frequency magnetron sputtering and angular ion beam polishing to achieve an ultrathin,ultrasmooth platinum(Pt)electrode film(UTPF)with a thickness of less than 10 nm.Building on this,a vapor deposition method with dynamically regulated evaporation rates is developed to obtain a dense-gradient PbI_(2)precursor.This funnel-shaped vertical structure precursor facilitates the penetration of CH_(3)NH_(3)I solution,ultimately resulting in a dense and uniform perovskite film with large grains and strong interfacial bonding with UTPF.The results indicate that the flexible PD arrays exhibit excellent optoelectronic performances,characterized by high sensitivity,detectivity and a large on/off current ratio.Furthermore,benefitting from their exceptional flexibility and electrical stability,the devices retain 92.53%of the original photocurrent after 4000 bending cycles at large angles.Notably,the integrated 10×10 flexible PD arrays demonstrate good uniformity in dark current and photocurrent,along with high imaging resolution,showing the reliable imaging capabilities of the flexible arrays and their potential applications in artificial retina.
基金supported by the National Natural Science Foundation of China(U20A20247,51922038,22302065 and 12104434)the National Key Research and Development Program of the Ministry of Science and Technology(2022YFA1402504)+2 种基金the Guangdong Basic and Applied Basic Research Foundation(2023A1515012176)the Science and Technology Innovation Program of Hunan Province(2024RC3081)the Hunan Natural Science Foundation(2023JJ40140 and 2024JJ4009).
文摘Prussian blue analogues(PBAs)are increasingly recognized as promising cathode materials for potassium-ion batteries(PIBs)owing to their low cost,distinctive open structure,and high theoretical capacity.However,PBAs still face challenges related to low crystallinity and elevated crystal water content,adversely affecting their performance as cathodes.This study proposes a straightforward low-temperature synthesis method for PBAs termed cryo-synthesized PBAs.The nucleation and growth processes were effectively slowed down by precisely controlling the synthesis temperature.This approach successfully yields PBAs with enhanced crystallinity and uniform particle size.The PBA electrode utilized as the cathode in PIBs demonstrates remarkable long-term cycling stability over 10,000 cycles at a current density of 2000 mA g^(-1).We believe these findings will promote the widespread adoption of PBAs in aqueous PIBs,paving the way for large-scale,cost-effective applications.
基金supported by the National Nature Science Foundation of China(Nos.U20A20247 and 52101252)the National Key Research and Development Program of Ministry of Science and Technology(2022YFA1402504)+1 种基金the Guangdong Basic and Applied Basic Research Foundation(No.2023A1515030196)support through the R.A.Bowen Endowed Professorship funds.
文摘The poor electronic conductivity of conversion-type materials(CMs)and the dissolution/diffusion loss of transition metal(TM)ions in electrodes seriously hinder the practical applications of potassium ion batteries.Simply optimizing the electrode materials or designing the electrode components is no longer effective in improving the performance of CMs.Binders,as one of the elec-trode components,play a vital role in improving the electrochemical per-formance of batteries.Here we rationally designed FeF_(2) electrodes for the first time by optimizing electrode materials with the introduction of carbon na-notubes(CNTs)and combined with a sodium alginate(SA)binder based on strong interactions.We show that the FeF_(2)@CNTs-SA cathode does not suffer from TM ion dissolution and delivers a high capacity of 184.7 mAh g^(-1) at 10 mA g^(-1).Moreover,the capacity of FeF_(2)@CNTs-SA is as high as 99.2 mAh g^(-1) after 100 cycles at 100 mA g^(-1),which is a twofold increase compared to FeF_(2)@CNTs-PVDF.After calculating the average capacity decay rate per cycle of them,we find that FeF_(2)@CNTs-SA is about one-third lower than FeF_(2)@CNTs-PVDF.Therefore,the SA binder can be broadly used for electrodes comprising several CMs,providing meaningful insights into mechanisms that lead to their improved electrochemical performances.
基金supported by the National Natural Science Foundation of China(Grant Nos.U22B20104,52407080,52277090,52207097)the International Science and Technology Cooperation Program of China(Grant No.2022YFE0129300)+2 种基金the Science and Technology Innovation Program of Hunan Province(Grant No.2023RC3102)the Excellent Innovation Youth Program of Changsha of China(Grant No.kq2209010)the Key Research and Development Program of Hunan Province(Grant No.2023GK2007)。
文摘Islanded microgrids(IMGs)offer a viable and efficient energy self-sustaining solution for distributed resources in remote areas.While without utility grid support,the frequency of IMG is susceptible to mismatches between demand and generation.Moreover,IMGs encounter uncertain and nonlinear load disturbances together with system parameter perturbation,which further compromises frequency stability.To this aim,this paper proposes a robust multi-virtual synchronous generators(multi-VSGs)coordinated control strategy for distributed secondary frequency regulation(DSFR)in IMGs,which exhibits minimal model dependency and avoids reliance on global information.Two critical methods are developed:(1)a robust VSG control framework that incorporates the linear active disturbance rejection control(LADRC)technique,which enables the estimation and effective elimination of uncertain load disturbances and system's parameter perturbations;(2)a novel secondorder consensus algorithm-based control law for robust secondary frequency regulation,which is featured with proper power sharing among different participants,suppressed power oscillation caused by response disparities,and reduced reliance on complex communication system.Building on methods(1)and(2),a novel multi-VSGs coordinated control strategy is proposed,providing a robust solution for IMG's frequency restoration,and its dynamic characteristics are explored in detail.The correctness and effectiveness of the proposal are verified by both simulation and the hardware-in-the-loop(HIL)experiment results across typical scenarios.
