The implementation of ultrahigh-Ni cathodes in high-energy lithium-ion batteries(LIBs)is constrained by significant structural and interfacial degradation during cycling.In this study,doping-induced surface restructur...The implementation of ultrahigh-Ni cathodes in high-energy lithium-ion batteries(LIBs)is constrained by significant structural and interfacial degradation during cycling.In this study,doping-induced surface restructuring in ultrahigh-nickel cathode materials is rapidly facilitated through an ultrafast Joule heating method.Density functional theory(DFT)calculations,synchrotron X-ray absorption spectroscopy(XAS),and single-particle force test confirmed the establishment of a stable crystal framework and lattice oxygen,which mitigated H2-H3 phase transitions and improved structural reversibility.Additionally,the Sc doping process exhibits a pinning effect on the grain boundaries,as shown by scanning transmission electron microscopy(STEM),enhancing Li~+diffusion kinetics and decreasing mechanical strain during cycling.The in situ development of a cation-mixing layer at grain boundaries also creates a robust cathode/electrolyte interphase,effectively reducing interfacial parasitic reactions and transition metal dissolution,as validated by STEM and time-of-flight secondary ion mass spectrometry(TOF-SIMS).These synergistic modifications reduce particle cracking and surface/interface degradation,leading to enhanced rate capability,structural integrity,and thermal stability.Consequently,the optimized Sc-modified ultrahigh-Ni cathode(Sc-1)exhibits 93.99%capacity retention after 100 cycles at 1 C(25℃)and87.06%capacity retention after 100 cycles at 1 C(50℃),indicating excellent cycling and thermal stability.By presenting a one-step multifunctional modification approach,this research delivers an extensive analysis of the mechanisms governing the structure,microstructure,and interface properties of nickel-rich layered cathode materials(NCMs).These results underscore the potential of ultrahigh-Ni cathodes as viable candidates for advanced lithium-ion batteries(LIBs)in next-generation electric vehicles(EVs).展开更多
Achieving high-level integration of composite micro-nano structures with different structural characteristics through a minimalist and universal process has long been the goal pursued by advanced manufacturing researc...Achieving high-level integration of composite micro-nano structures with different structural characteristics through a minimalist and universal process has long been the goal pursued by advanced manufacturing research but is rarely explored due to the absence of instructive mechanisms.Here,we revealed a controllable ultrafast laser-induced focal volume light field and experimentally succeeded in highly efficient one-step composite structuring in multiple transparent solids.A pair of spatially coupled twin periodic structures reflecting light distribution in the focal volume are simultaneously created and independently tuned by engineering ultrafast laser-matter interaction.We demonstrated that the generated composite micro-nano structures are applicable to multi-dimensional information integration,nonlinear diffractive elements,and multi-functional optical modulation.This work presents the experimental verification of highly universal all-optical fabrication of composite micro-nano structures with independent controllability in multiple degrees of freedom,expands the current cognition of ultrafast laser-based material modification in transparent solids,and establishes a new scientific aspect of strong-field optics,namely,focal volume optics for composite structuring transparent solids.展开更多
Metal additive manufacturing(MAM)enables near-net shape production of components with minimized waste and excellent mechanical performance based on multi-scale microstructural heterogeneity.Espe-cially,the dislocation...Metal additive manufacturing(MAM)enables near-net shape production of components with minimized waste and excellent mechanical performance based on multi-scale microstructural heterogeneity.Espe-cially,the dislocation cell network that often bears elemental segregation or precipitation of a secondary phase contributes to enhancing the strength of additively manufactured materials.The cell boundaries can also act as active nucleation sites for the formation of precipitates under post-MAM heat treatment,as the chemical heterogeneity and profuse dislocations generate a driving force for precipitation.In this work,we subjected a Co_(18)Cr_(15)Fe_(50)Ni_(10)Mo_(6.5)C_(0.5)(at%)medium-entropy alloy fabricated by laser powder bed fusion(LPBF)to post-LPBF annealing at 900℃for 10 min.Microstructural investigation revealed that the cell boundaries of the as-built sample,which were decorated by Mo segregation,are replaced byμphase andM_(6)C typecarbide precipitatesduringannealingwhile thegrainstructureand sizeremain unaffected,indicating that the post-LPBF annealing delivered the proper amount of heat input to alter only the cell structure.The yield strength slightly decreased with annealing due to a reduction in the strengthening effect by the cell boundaries despite an increased precipitation strengthening effect.How-ever,the post-LPBF annealing improved the strain hardenability and the ultimate tensile strength was enhanced from∼1.02 to∼1.15 GPa owing to reinforced back stress hardening by the increased disloca-tion pile-up at the precipitates.Our results suggest that the cell structure with chemical heterogeneity can be successfully controlled by careful post-MAM heat treatment to tailor the mechanical performance,while also providing insight into alloy design for additive manufacturing.展开更多
Advancing aqueous zinc-ion batteries(AZIBs)are significantly challenged by the need to find cathode materials that can provide both high capacity and fast reaction kinetics.Tellurium telluride,a topological insulator,...Advancing aqueous zinc-ion batteries(AZIBs)are significantly challenged by the need to find cathode materials that can provide both high capacity and fast reaction kinetics.Tellurium telluride,a topological insulator,has emerged as a promising cathode candidate for AZIBs,garnering increasing attention.However,the complete understanding of its electrochemical reaction mechanism and its unsatisfactory energy storage performance are major obstacles to the practical use.In this work,we synthesize a bimetallic bismuth-nickel telluride with Te vacancies,defined as Bi_(2)Te_(3-x)/NiTe_(2),which forms a topological insulator/topological Dirac semimetal heterostructure through a hydrothermal approach.The electrochemical reaction mechanism of Bi_(2)Te_(3-x)/NiTe_(2),along with its phase and structural changes are elucidated by using in-situ X-ray diffraction,various electrochemical techniques,and ex-situ characterizations.The influences of Bi_(2)Te_(3-x)/NiTe_(2)on the electronic structure,interracial electron transfer,migration barrier,and ion adsorption energy are investigated by using density functional theory calculations.Our findings reveal that Bi_(2)Te_(3-x)/NiTe_(2)exhibits excellent specific capacity,stable cycling,and superior rate capability as a cathode material for AZIBs.Moreover,further studies demonstrate that Bi_(2)Te_(3-x)/NiTe_(2)maintains exceptional performance at low temperatures of-15 and-5℃,and also retains stability and flexibility when integrated into flexible battery packs.展开更多
Currently,the Al_(2)O_(3)content in the high-alumina slag systems within blast furnaces is generally limited to 16wt%–18.5wt%,making it challenging to overcome this limitation.Unlike most studies that concentrated on...Currently,the Al_(2)O_(3)content in the high-alumina slag systems within blast furnaces is generally limited to 16wt%–18.5wt%,making it challenging to overcome this limitation.Unlike most studies that concentrated on managing the MgO/Al_(2)O_(3)ratio or basicity,this paper explored the effect of equimolar substitution of MgO for CaO on the viscosity and structure of a high-alumina CaO-MgO-Al_(2)O_(3)-SiO_(2)slag system,providing theoretical guidance and data to facilitate the application of high-alumina ores.The results revealed that the viscosity first decreased and then increased with higher MgO substitution,reaching a minimum at 15mol%MgO concentration.Fourier transform infrared spectroscopy(FTIR)results found that the depths of the troughs representing[SiO_(4)]tetrahedra,[AlO_(4)]tetrahedra,and Si-O-Al bending became progressively deeper with increased MgO substitution.Deconvolution of the Raman spectra showed that the average number of bridging oxygens per Si atom and the X_(Q^(3))/X_(Q^(2))(X_(Q^(i))is the molar fraction of Q^(i) unit,and i is the number of bridging oxygens in a[SiO_(4)]tetrahedral unit)ratio increased from 2.30 and 1.02 to 2.52 and 2.14,respectively,indicating a progressive polymerization of the silicate structure.X-ray photoelectron spectroscopy(XPS)results highlighted that non-bridging oxygen content decreased from 77.97mol% to 63.41mol% with increasing MgO concentration,whereas bridging oxygen and free oxygen contents increased.Structural analysis demonstrated a gradual increase in the polymerization degree of the tetrahedral structure with the increase in MgO substitution.However,bond strength is another important factor affecting the slag viscosity.The occurrence of a viscosity minimum can be attributed to the complex evolution of bond strengths of non-bridging oxygens generated during depolymerization of the[SiO_(4)]and[AlO_(4)]tetrahedral structures by CaO and MgO.展开更多
Based on inspection data,the authors analyze and summarize the main types and distribution characteristics of tunnel structural defects.These defects are classified into three types:surface defects,internal defects,an...Based on inspection data,the authors analyze and summarize the main types and distribution characteristics of tunnel structural defects.These defects are classified into three types:surface defects,internal defects,and defects behind the structure.To address the need for rapid detection of different defect types,the current state of rapid detection technologies and equipment,both domestically and internationally,is systematically reviewed.The research reveals that surface defect detection technologies and equipment have developed rapidly in recent years.Notably,the integration of machine vision and laser scanning technologies have significantly improved detection efficiency and accuracy,achieving crack detection precision of up to 0.1 mm.However,the non-contact rapid detection of internal and behind-the-structure defects remains constrained by hardware limitations,with traditional detection remaining dominant.Nevertheless,phased array radar,ultrasonic,and acoustic vibration detection technologies have become research hotspots in recent years,offering promising directions for detecting these challenging defect types.Additionally,the application of multisensor fusion technology in rapid detection equipment has further enhanced detection capabilities.Devices such as cameras,3D laser scanners,infrared thermal imagers,and radar demonstrate significant advantages in rapid detection.Future research in tunnel inspection should prioritize breakthroughs in rapid detection technologies for internal and behind-the-structure defects.Efforts should also focus on developing multifunctional integrated detection vehicles that can simultaneously inspect both surface and internal structures.Furthermore,progress in fully automated,intelligent systems with precise defect identification and real-time reporting will be essential to significantly improve the efficiency and accuracy of tunnel inspection.展开更多
The utilization of iron coke provides a green pathway for low-carbon ironmaking.To uncover the influence mechanism of iron ore on the behavior and kinetics of iron coke gasification,the effect of iron ore on the micro...The utilization of iron coke provides a green pathway for low-carbon ironmaking.To uncover the influence mechanism of iron ore on the behavior and kinetics of iron coke gasification,the effect of iron ore on the microstructure of iron coke was investigated.Furthermore,a comparative study of the gasification reactions between iron coke and coke was conducted through non-isothermal thermogravimetric method.The findings indicate that compared to coke,iron coke exhibits an augmentation in micropores and specific surface area,and the micropores further extend and interconnect.This provides more adsorption sites for CO_(2) molecules during the gasification process,resulting in a reduction in the initial gasification temperature of iron coke.Accelerating the heating rate in non-isothermal gasification can enhance the reactivity of iron coke.The metallic iron reduced from iron ore is embedded in the carbon matrix,reducing the orderliness of the carbon structure,which is primarily responsible for the heightened reactivity of the carbon atoms.The kinetic study indicates that the random pore model can effectively represent the gasification process of iron coke due to its rich pore structure.Moreover,as the proportion of iron ore increases,the activation energy for the carbon gasification gradually decreases,from 246.2 kJ/mol for coke to 192.5 kJ/mol for iron coke 15wt%.展开更多
With vigorous developments in nanotechnology,the elaborate regulation of microstructure shows attractive potential in the design of electromagnetic wave absorbers.Herein,a hierarchical porous structure and composite h...With vigorous developments in nanotechnology,the elaborate regulation of microstructure shows attractive potential in the design of electromagnetic wave absorbers.Herein,a hierarchical porous structure and composite heterogeneous interface are constructed successfully to optimize the electromagnetic loss capacity.The macro–micro-synergistic graphene aerogel formed by the ice template‑assisted 3D printing strategy is cut by silicon carbide nanowires(SiC_(nws))grown in situ,while boron nitride(BN)interfacial structure is introduced on graphene nanoplates.The unique composite structure forces multiple scattering of incident EMWs,ensuring the combined effects of interfacial polarization,conduction networks,and magnetic-dielectric synergy.Therefore,the as-prepared composites present a minimum reflection loss value of−37.8 dB and a wide effective absorption bandwidth(EAB)of 9.2 GHz(from 8.8 to 18.0 GHz)at 2.5 mm.Besides,relying on the intrinsic high-temperature resistance of SiC_(nws) and BN,the EAB also remains above 5.0 GHz after annealing in air environment at 600℃ for 10 h.展开更多
To expand the study on the structures and biological activities of the anthracyclines anticancer drugs and reduce their toxic side effects,the new anthraquinone derivatives,9‑pyridylanthrahydrazone(9‑PAH)and 9,10‑bisp...To expand the study on the structures and biological activities of the anthracyclines anticancer drugs and reduce their toxic side effects,the new anthraquinone derivatives,9‑pyridylanthrahydrazone(9‑PAH)and 9,10‑bispyridylanthrahydrazone(9,10‑PAH)were designed and synthesized.Utilizing 9‑PAH and 9,10‑PAH as promising anticancer ligands,their respective copper complexes,namely[Cu(L1)Cl_(2)]Cl(1)and{[Cu_(4)(μ_(2)‑Cl)_(3)Cl_(4)(9,10‑PAH)_(2)(DMSO)_(2)]Cl_(2)}_(n)(2),were subsequently synthesized,where the new ligand L1 is formed by coupling two 9‑PAH ligands in the coordination reaction.The chemical and crystal structures of 1 and 2 were elucidated by IR,MS,elemental analysis,and single‑crystal X‑ray diffraction.Complex 1 forms a mononuclear structure.L1 coordinates with Cu through its three N atoms,together with two Cl atoms,to form a five‑coordinated square pyramidal geometry.Complex 2 constitutes a polymeric structure,wherein each structural unit centrosymmetrically encompasses two five‑coordinated binuclear copper complexes(Cu1,Cu2)of 9,10‑PAH,with similar square pyramidal geometry.A chlorine atom(Cl_(2)),located at the symmetry center,bridges Cu1 and Cu1A to connect the two binuclear copper structures.Meanwhile,the two five‑coordinated Cu2 atoms symmetrically bridge the adjacent structural units via one coordinated Cl atom,respectively,thus forming a 1D chain‑like polymeric structure.In vitro anticancer activity assessments revealed that 1 and 2 showed significant cytotoxicity even higher than cisplatin.Specifically,the IC_(50)values of 2 against HeLa‑229 and SK‑OV‑3 cancer cell lines were determined to be(5.92±0.32)μmol·L^(-1)and(6.48±0.39)μmol·L^(-1),respectively.2 could also block the proliferation of HeLa‑229 cells in S phase and significantly induce cell apoptosis.In addition,fluorescence quenching competition experiments suggested that 2 might interact with DNA by an intercalative binding mode,offering insights into its underlying anticancer mechanism.CCDC:2388918,1;2388919,2.展开更多
Brazing filler metals are widely applied,which serve as an industrial adhesive in the joining of dissimilar structures.With the continuous emergence of new structures and materials,the demand for novel brazing filler ...Brazing filler metals are widely applied,which serve as an industrial adhesive in the joining of dissimilar structures.With the continuous emergence of new structures and materials,the demand for novel brazing filler metals is ever-increasing.It is of great significance to investigate the optimized composition design methods and to establish systematic design guidelines for brazing filler metals.This study elucidated the fundamental rules for the composition design of brazing filler metals from a three-dimensional perspective encompassing the basic properties of applied brazing filler metals,formability and processability,and overall cost.The basic properties of brazing filler metals refer to their mechanical properties,physicochemical properties,electromagnetic properties,corrosion resistance,and the wettability and fluidity during brazing.The formability and processability of brazing filler metals include the processes of smelting and casting,extrusion,rolling,drawing and ring-making,as well as the processes of granulation,powder production,and the molding of amorphous and microcrystalline structures.The cost of brazing filler metals corresponds to the sum of materials value and manufacturing cost.Improving the comprehensive properties of brazing filler metals requires a comprehensive and systematic consideration of design indicators.Highlighting the unique characteristics of brazing filler metals should focus on relevant technical indicators.Binary or ternary eutectic structures can effectively enhance the flow spreading ability of brazing filler metals,and solid solution structures contribute to the formability.By employing the proposed design guidelines,typical Ag based,Cu based,Zn based brazing filler metals,and Sn based solders were designed and successfully applied in major scientific and engineering projects.展开更多
As-forged WSTi6421 titanium alloy billet afterβannealing was investigated.Abnormally coarse grains larger than adjacent grains could be observed in the microstructures,forming abnormal grain structures with uneven si...As-forged WSTi6421 titanium alloy billet afterβannealing was investigated.Abnormally coarse grains larger than adjacent grains could be observed in the microstructures,forming abnormal grain structures with uneven size distribution.Through electron backscattered diffraction(EBSD),the forged microstructure at various locations of as-forged WSTi6421 titanium alloy billet was analyzed,revealing that the strength of theβphase cubic texture generated by forging significantly influences the grain size afterβannealing.Heat treatment experiments were conducted within the temperature range from T_(β)−50°C to T_(β)+10°C to observe the macro-and micro-morphologies.Results show that the cubic texture ofβphase caused by forging impacts the texture of the secondaryαphase,which subsequently influences theβphase formed during the post-βannealing process.Moreover,the pinning effect of the residual primaryαphase plays a crucial role in the growth ofβgrains during theβannealing process.EBSD analysis results suggest that the strength ofβphase with cubic texture formed during forging process impacts the orientation distribution differences ofβgrains afterβannealing.Additionally,the development of grains with large orientations within the cubic texture shows a certain degree of selectivity duringβannealing,which is affected by various factors,including the pinning effect of the primaryαphase,the strength of the matrix cubic texture,and the orientation relationship betweenβgrain and matrix.Comprehensively,the stronger the texture in a certain region,the less likely the large misoriented grains suffering secondary growth,thereby aggregating the difference in microstructure and grain orientation distribution across different regions afterβannealing.展开更多
It is of great scientific significance to construct a 3D dynamic structural color with a special color effect based on the microlens array.However,the problems of imperfect mechanisms and poor color quality need to be...It is of great scientific significance to construct a 3D dynamic structural color with a special color effect based on the microlens array.However,the problems of imperfect mechanisms and poor color quality need to be solved.A method of 3D structural color turning on periodic metasurfaces fabricated by the microlens array and self-assembly technology was proposed in this study.In the experiment,Polydimethylsiloxane(PDMS)flexible film was used as a substrate,and SiO2 microspheres were scraped into grooves of the PDMS film to form 3D photonic crystal structures.By adjusting the number of blade-coated times and microsphere concentrations,high-saturation structural color micropatterns were obtained.These films were then matched with microlens arrays to produce dynamic graphics with iridescent effects.The results showed that by blade-coated two times and SiO2 microsphere concentrations of 50%are the best conditions.This method demonstrates the potential for being widely applied in the anticounterfeiting printing and ultra-high-resolution display.展开更多
With the increasing complexity of the current electromagnetic environment,excessive microwave radi-ation not only does harm to human health but also forms various electromagnetic interference to so-phisticated electro...With the increasing complexity of the current electromagnetic environment,excessive microwave radi-ation not only does harm to human health but also forms various electromagnetic interference to so-phisticated electronic instruments.Therefore,the design and preparation of electromagnetic absorbing composites represent an efficient approach to mitigate the current hazards of electromagnetic radiation.However,traditional electromagnetic absorbers are difficult to satisfy the demands of actual utilization in the face of new challenges,and emerging absorbents have garnered increasing attention due to their structure and performance-based advantages.In this review,several emerging composites of Mxene-based,biochar-based,chiral,and heat-resisting are discussed in detail,including their synthetic strategy,structural superiority and regulation method,and final optimization of electromagnetic absorption ca-pacity.These insights provide a comprehensive reference for the future development of new-generation electromagnetic-wave absorption composites.Moreover,the potential development directions of these emerging absorbers have been proposed as well.展开更多
As the proportion of composite materials used in aircraft continues to increase, the electromagnetic Shielding Effectiveness (SE) of these materials becomes a critical factor in the electromagnetic safety design of ai...As the proportion of composite materials used in aircraft continues to increase, the electromagnetic Shielding Effectiveness (SE) of these materials becomes a critical factor in the electromagnetic safety design of aircraft structures. The assessment of electromagnetic SE for Slotted Composite Structures(SCSs) is particularly challenging due to their complex geometries and there remains a lack of suitable models for accurately predicting the SE performance of these intricate configurations. To address this issue, this paper introduces SCS-Net, a Deep Neural Network (DNN) method designed to accurately predict the SE of SCS. This method considers the impacts of various structural parameters, material properties and incident wave parameters on the SE of SCSs. In order to better model the SCS, an improved Nicolson-Ross-Weir (NRW) method is introduced in this paper to provide an equivalent flat structure for the SCS and to calculate the electromagnetic parameters of the equivalent structure. Additionally, the prediction of SE via DNNs is limited by insufficient test data, which hinders support for large-sample training. To address the issue of limited measured data, this paper develops a Measurement-Computation Fusion (MCF) dataset construction method. The predictions based on the simulation results show that the proposed method maintains an error of less than 0.07 dB within the 8–10 GHz frequency range. Furthermore, a new loss function based on the weighted L1-norm is established to improve the prediction accuracy for these parameters. Compared with traditional loss functions, the new loss function reduces the maximum prediction error for equivalent electromagnetic parameters by 47%. This method significantly improves the prediction accuracy of SCS-Net for measured data, with a maximum improvement of 23.88%. These findings demonstrate that the proposed method enables precise SE prediction and design for composite structures while reducing the number of test samples needed.展开更多
The stability and electrocatalytic efficiency of transition metal oxides for water splitting is determined by geometric and electronic structure,especially under high current densities.Herein,a newly designed lamella-...The stability and electrocatalytic efficiency of transition metal oxides for water splitting is determined by geometric and electronic structure,especially under high current densities.Herein,a newly designed lamella-heterostructured nanoporous CoFe/CoFe_(2)O_(4) and CeO_(2−x),in situ grown on nickel foam(NF),holds great promise as a high-efficient bifunctional electrocatalyst(named R-CoFe/Ce/NF)for water splitting.Experimental characterization verifies surface reconstruction from CoFe alloy/oxide to highly active CoFeOOH during in situ electrochemical polarization.By virtues of three-dimensional nanoporous architecture and abundant electroactive CoFeOOH/CeO_(2−x) heterostructure interfaces,the R-CoFe/Ce/NF electrode achieves low overpotentials for oxygen evolution(η_(10)=227 mV;η_(500)=450 mV)and hydrogen evolution(η_(10)=35 mV;η_(408)=560 mV)reactions with high normalized electrochemical active surface areas,respectively.Additionally,the alkaline full water splitting electrolyzer of R-CoFe/Ce/NF||R-CoFe/Ce/NF achieves a current density of 50 mA·cm^(−2) only at 1.75 V;the decline of activity is satisfactory after 100-h durability test at 300 mA·cm^(−2).Density functional theory also demonstrates that the electron can transfer from CeO_(2−x) by virtue of O atom to CoFeOOH at CoFeOOH/CeO_(2−x) heterointerfaces and enhancing the adsorption of reactant,thus optimizing electronic structure and Gibbs free energies for the improvement of the activity for water splitting.展开更多
The rapid development of 5G communication technology and smart electronic and electrical equipment will inevitably lead to electromagnetic radiation pollution.Enriching heterointerface polarization relaxation through ...The rapid development of 5G communication technology and smart electronic and electrical equipment will inevitably lead to electromagnetic radiation pollution.Enriching heterointerface polarization relaxation through nanostructure design and interface modifica-tion has proven to be an effective strategy to obtain efficient electromagnetic wave absorption.Here,this work implements an innovative method that combines biomimetic honeycomb superstructure to constrain hierarchical porous heterostructure composed of Co/CoO nano-particles to improve the interfacial polarization intensity.The method effectively controlled the absorption efficiency of Co^(2+)through de-lignification modification of bamboo,and combined with the bionic carbon-based natural hierarchical porous structure to achieve uniform dispersion of nanoparticles,which is conducive to the in-depth construction of heterogeneous interfaces.In addition,the multiphase struc-ture brought about by high-temperature pyrolysis provides the best dielectric loss and impedance matching for the material.Therefore,the obtained bamboo-based Co/CoO multiphase composite showed excellent electromagnetic wave absorption performance,achieving excel-lent reflection loss(RL)of-79 dB and effective absorption band width of 4.12 GHz(6.84-10.96 GHz)at low load of 15wt%.Among them,the material’s optimal radar cross-section(RCS)reduction value can reach 31.9 dB·m^(2).This work provides a new approach to the micro-control and comprehensive optimization of macro-design of microwave absorbers,and offers new ideas for the high-value utiliza-tion of biomass materials.展开更多
High-temperature microwave absorbing materials(MAMs)and structures are increasingly appealing due to their critical role in stealth applications under harsh environments.However,the impedance mismatch caused by increa...High-temperature microwave absorbing materials(MAMs)and structures are increasingly appealing due to their critical role in stealth applications under harsh environments.However,the impedance mismatch caused by increased conduction loss often leads to a significant decline in electromagnetic wave absorp-tion(EMWA)performance at elevated temperatures,which severely restricts their practical application.In this study,we propose a novel approach for efficient electromagnetic wave absorption across a wide temperature range using reduced graphene oxide(RGO)/epoxy resin(EP)metacomposites that integrate both electromagnetic parameters and metamaterial design concepts.Due to the discrete distribution of the units,electromagnetic waves can more easily penetrate the interior of materials,thereby exhibiting stable microwave absorption(MA)performance and impedance-matching characteristics suitable across a wide temperature range.Consequently,exceptional MA properties can be achieved within the tem-perature range from 298 to 473 K.Furthermore,by carefully controlling the structural parameters in RGO metacomposites,both the resonant frequency and effective absorption bandwidth(EAB)can be optimized based on precise manipulation of equivalent electromagnetic parameters.This study not only provides an effective approach for the rational design of MA performance but also offers novel insights into achieving super metamaterials with outstanding performance across a wide temperature spectrum.展开更多
Cells,tissues,and organs are constantly subjected to the action of mechanical forces from the extracellular environment-and the nervous system is no exception.Cell-intrinsic properties such as membrane lipid compositi...Cells,tissues,and organs are constantly subjected to the action of mechanical forces from the extracellular environment-and the nervous system is no exception.Cell-intrinsic properties such as membrane lipid composition,abundance of mechanosensors,and cytoskeletal dynamics make cells more or less likely to sense these forces.Intrinsic and extrinsic cues are integrated by cells and this combined information determines the rate and dynamics of membrane protrusion growth or retraction(Yamada and Sixt,2019).Cell protrusions are extensions of the plasma membrane that play crucial roles in diverse contexts such as cell migration and neuronal synapse formation.In the nervous system,neurons are highly dynamic cells that can change the size and number of their pre-and postsynaptic elements(called synaptic boutons and dendritic spines,respectively),in response to changes in the levels of synaptic activity through a process called plasticity.Synaptic plasticity is a hallmark of the nervous system and is present throughout our lives,being required for functions like memory formation or the learning of new motor skills(Minegishi et al.,2023;Pillai and Franze,2024).展开更多
In the present work,by virtue of the synergistic and independent effects of Janus structure,an asymmetric nickel-chain/multiwall carbon nanotube/polyimide(Ni/MWCNTs/PI)composite foam with absorption-dominated electrom...In the present work,by virtue of the synergistic and independent effects of Janus structure,an asymmetric nickel-chain/multiwall carbon nanotube/polyimide(Ni/MWCNTs/PI)composite foam with absorption-dominated electromagnetic interference(EMI)shielding and thermal insulation performances was successfully fabricated through an ordered casting and directional freeze-drying strategy.Water-soluble polyamic acid(PAA)was chosen to match the oriented freeze-drying method to acquire oriented pores,and the thermal imidization process from PAA to PI exactly eliminated the interface of the multilayered structure.By controlling the electro-magnetic gradient and propagation path of the incident microwaves in the MWCNT/PI and Ni/PI layers,the PI composite foam exhibited an efficient EMI SE of 55.8 dB in the X-band with extremely low reflection characteristics(R=0.22).The asymmetric conductive net-work also greatly preserved the thermal insulation properties of PI.The thermal conductivity(TC)of the Ni/MWCNT/PI composite foam was as low as 0.032 W/(m K).In addition,owing to the elimination of MWCNT/PI and Ni/PI interfaces during the thermal imidization process,the composite foam showed satisfactory compressive strength.The fabricated PI composite foam could provide reliable electromagnetic protection in complex applications and withstand high temperatures,which has great potential in cuttingedge applications such as advanced aircraft.展开更多
Cholesteric liquid crystals(CLCs)exhibit unique helical superstructures that selectively reflect circularly polarized light,enabling them to dynamically respond to environmental changes with tunable structural colors....Cholesteric liquid crystals(CLCs)exhibit unique helical superstructures that selectively reflect circularly polarized light,enabling them to dynamically respond to environmental changes with tunable structural colors.This dynamic color-changing capability is crucial for applications that require adaptable optical properties,positioning CLCs as key materials in advanced photonic technologies.This review focuses on the mechanisms of dynamic color tuning in CLCs across various forms,including small molecules,cholesteric liquid crystal elastomers(CLCEs),and cholesteric liquid crystal networks(CLCNs),and emphasizes the distinct responsive coloration each structure provides.Key developments in photochromic mechanisms based on azobenzene,dithienylethene,and molecular motor switches,are discussed for their roles in enhancing the stability and tuning range of CLCs.We examine the color-changing behaviors of CLCEs under mechanical stimuli and CLCNs under swelling,highlighting the advantages of each form.Following this,applications of dynamic color-tuning CLCs in information encryption,adaptive camouflage,and smart sensing technologies are explored.The review concludes with an outlook on current challenges and future directions in CLC research,particularly in biomimetic systems and dynamic photonic devices,aiming to broaden their functional applications and impact.展开更多
基金supported by the National Key R&D Program of China(2022YFB3803501)the National Natural Science Foundation of China(22179008,22209156)+5 种基金support from the Beijing Nova Program(20230484241)support from the China Postdoctoral Science Foundation(2024M754084)the Postdoctoral Fellowship Program of CPSF(GZB20230931)support from beamline BL08U1A of Shanghai Synchrotron Radiation Facility(2024-SSRF-PT-506950)beamline 1W1B of the Beijing Synchrotron Radiation Facility(2021-BEPC-PT-006276)support from Initial Energy Science&Technology Co.,Ltd(IEST)。
文摘The implementation of ultrahigh-Ni cathodes in high-energy lithium-ion batteries(LIBs)is constrained by significant structural and interfacial degradation during cycling.In this study,doping-induced surface restructuring in ultrahigh-nickel cathode materials is rapidly facilitated through an ultrafast Joule heating method.Density functional theory(DFT)calculations,synchrotron X-ray absorption spectroscopy(XAS),and single-particle force test confirmed the establishment of a stable crystal framework and lattice oxygen,which mitigated H2-H3 phase transitions and improved structural reversibility.Additionally,the Sc doping process exhibits a pinning effect on the grain boundaries,as shown by scanning transmission electron microscopy(STEM),enhancing Li~+diffusion kinetics and decreasing mechanical strain during cycling.The in situ development of a cation-mixing layer at grain boundaries also creates a robust cathode/electrolyte interphase,effectively reducing interfacial parasitic reactions and transition metal dissolution,as validated by STEM and time-of-flight secondary ion mass spectrometry(TOF-SIMS).These synergistic modifications reduce particle cracking and surface/interface degradation,leading to enhanced rate capability,structural integrity,and thermal stability.Consequently,the optimized Sc-modified ultrahigh-Ni cathode(Sc-1)exhibits 93.99%capacity retention after 100 cycles at 1 C(25℃)and87.06%capacity retention after 100 cycles at 1 C(50℃),indicating excellent cycling and thermal stability.By presenting a one-step multifunctional modification approach,this research delivers an extensive analysis of the mechanisms governing the structure,microstructure,and interface properties of nickel-rich layered cathode materials(NCMs).These results underscore the potential of ultrahigh-Ni cathodes as viable candidates for advanced lithium-ion batteries(LIBs)in next-generation electric vehicles(EVs).
基金financially supported by the National Key Research and Development Program of China(No.2021YFB2802001)the National Natural Science Foundation of China(Grant Nos.12304349,U20A20211,62275233)the Postdoctoral Fellowship Program of CPSF(GZB20230628,GZC20241465)。
文摘Achieving high-level integration of composite micro-nano structures with different structural characteristics through a minimalist and universal process has long been the goal pursued by advanced manufacturing research but is rarely explored due to the absence of instructive mechanisms.Here,we revealed a controllable ultrafast laser-induced focal volume light field and experimentally succeeded in highly efficient one-step composite structuring in multiple transparent solids.A pair of spatially coupled twin periodic structures reflecting light distribution in the focal volume are simultaneously created and independently tuned by engineering ultrafast laser-matter interaction.We demonstrated that the generated composite micro-nano structures are applicable to multi-dimensional information integration,nonlinear diffractive elements,and multi-functional optical modulation.This work presents the experimental verification of highly universal all-optical fabrication of composite micro-nano structures with independent controllability in multiple degrees of freedom,expands the current cognition of ultrafast laser-based material modification in transparent solids,and establishes a new scientific aspect of strong-field optics,namely,focal volume optics for composite structuring transparent solids.
基金supported by the National Research Founda-tion of Korea(NRF)grant funded by the Korean government(MSIT)(Nos.2021R1A2C3006662 and RS-2023-00281246)supported by the Principal R&D project(contract no.PNK9950)of the Korean Institute of Materials Science(KIMS).
文摘Metal additive manufacturing(MAM)enables near-net shape production of components with minimized waste and excellent mechanical performance based on multi-scale microstructural heterogeneity.Espe-cially,the dislocation cell network that often bears elemental segregation or precipitation of a secondary phase contributes to enhancing the strength of additively manufactured materials.The cell boundaries can also act as active nucleation sites for the formation of precipitates under post-MAM heat treatment,as the chemical heterogeneity and profuse dislocations generate a driving force for precipitation.In this work,we subjected a Co_(18)Cr_(15)Fe_(50)Ni_(10)Mo_(6.5)C_(0.5)(at%)medium-entropy alloy fabricated by laser powder bed fusion(LPBF)to post-LPBF annealing at 900℃for 10 min.Microstructural investigation revealed that the cell boundaries of the as-built sample,which were decorated by Mo segregation,are replaced byμphase andM_(6)C typecarbide precipitatesduringannealingwhile thegrainstructureand sizeremain unaffected,indicating that the post-LPBF annealing delivered the proper amount of heat input to alter only the cell structure.The yield strength slightly decreased with annealing due to a reduction in the strengthening effect by the cell boundaries despite an increased precipitation strengthening effect.How-ever,the post-LPBF annealing improved the strain hardenability and the ultimate tensile strength was enhanced from∼1.02 to∼1.15 GPa owing to reinforced back stress hardening by the increased disloca-tion pile-up at the precipitates.Our results suggest that the cell structure with chemical heterogeneity can be successfully controlled by careful post-MAM heat treatment to tailor the mechanical performance,while also providing insight into alloy design for additive manufacturing.
基金supported by the National Natural Science Foundation of China(No.52372223)the Science Foundation of Shaanxi Province(No.2023-JC-ZD-03 and 2022GD-TSLD-15)Shaanxi Fundamental Science Research Project for Mathematics and Physics(No.23JSQ005)。
文摘Advancing aqueous zinc-ion batteries(AZIBs)are significantly challenged by the need to find cathode materials that can provide both high capacity and fast reaction kinetics.Tellurium telluride,a topological insulator,has emerged as a promising cathode candidate for AZIBs,garnering increasing attention.However,the complete understanding of its electrochemical reaction mechanism and its unsatisfactory energy storage performance are major obstacles to the practical use.In this work,we synthesize a bimetallic bismuth-nickel telluride with Te vacancies,defined as Bi_(2)Te_(3-x)/NiTe_(2),which forms a topological insulator/topological Dirac semimetal heterostructure through a hydrothermal approach.The electrochemical reaction mechanism of Bi_(2)Te_(3-x)/NiTe_(2),along with its phase and structural changes are elucidated by using in-situ X-ray diffraction,various electrochemical techniques,and ex-situ characterizations.The influences of Bi_(2)Te_(3-x)/NiTe_(2)on the electronic structure,interracial electron transfer,migration barrier,and ion adsorption energy are investigated by using density functional theory calculations.Our findings reveal that Bi_(2)Te_(3-x)/NiTe_(2)exhibits excellent specific capacity,stable cycling,and superior rate capability as a cathode material for AZIBs.Moreover,further studies demonstrate that Bi_(2)Te_(3-x)/NiTe_(2)maintains exceptional performance at low temperatures of-15 and-5℃,and also retains stability and flexibility when integrated into flexible battery packs.
基金financially supported by the National Natural Science Foundation of China(Nos.52425408 and 52304345)the Fundamental Research Funds for the Central Universities,China(No.2023CDJXY-016)the Postdoctoral Science Foundation of Chongqing(No.CSTB2023NSCQ-BHX0174)。
文摘Currently,the Al_(2)O_(3)content in the high-alumina slag systems within blast furnaces is generally limited to 16wt%–18.5wt%,making it challenging to overcome this limitation.Unlike most studies that concentrated on managing the MgO/Al_(2)O_(3)ratio or basicity,this paper explored the effect of equimolar substitution of MgO for CaO on the viscosity and structure of a high-alumina CaO-MgO-Al_(2)O_(3)-SiO_(2)slag system,providing theoretical guidance and data to facilitate the application of high-alumina ores.The results revealed that the viscosity first decreased and then increased with higher MgO substitution,reaching a minimum at 15mol%MgO concentration.Fourier transform infrared spectroscopy(FTIR)results found that the depths of the troughs representing[SiO_(4)]tetrahedra,[AlO_(4)]tetrahedra,and Si-O-Al bending became progressively deeper with increased MgO substitution.Deconvolution of the Raman spectra showed that the average number of bridging oxygens per Si atom and the X_(Q^(3))/X_(Q^(2))(X_(Q^(i))is the molar fraction of Q^(i) unit,and i is the number of bridging oxygens in a[SiO_(4)]tetrahedral unit)ratio increased from 2.30 and 1.02 to 2.52 and 2.14,respectively,indicating a progressive polymerization of the silicate structure.X-ray photoelectron spectroscopy(XPS)results highlighted that non-bridging oxygen content decreased from 77.97mol% to 63.41mol% with increasing MgO concentration,whereas bridging oxygen and free oxygen contents increased.Structural analysis demonstrated a gradual increase in the polymerization degree of the tetrahedral structure with the increase in MgO substitution.However,bond strength is another important factor affecting the slag viscosity.The occurrence of a viscosity minimum can be attributed to the complex evolution of bond strengths of non-bridging oxygens generated during depolymerization of the[SiO_(4)]and[AlO_(4)]tetrahedral structures by CaO and MgO.
文摘Based on inspection data,the authors analyze and summarize the main types and distribution characteristics of tunnel structural defects.These defects are classified into three types:surface defects,internal defects,and defects behind the structure.To address the need for rapid detection of different defect types,the current state of rapid detection technologies and equipment,both domestically and internationally,is systematically reviewed.The research reveals that surface defect detection technologies and equipment have developed rapidly in recent years.Notably,the integration of machine vision and laser scanning technologies have significantly improved detection efficiency and accuracy,achieving crack detection precision of up to 0.1 mm.However,the non-contact rapid detection of internal and behind-the-structure defects remains constrained by hardware limitations,with traditional detection remaining dominant.Nevertheless,phased array radar,ultrasonic,and acoustic vibration detection technologies have become research hotspots in recent years,offering promising directions for detecting these challenging defect types.Additionally,the application of multisensor fusion technology in rapid detection equipment has further enhanced detection capabilities.Devices such as cameras,3D laser scanners,infrared thermal imagers,and radar demonstrate significant advantages in rapid detection.Future research in tunnel inspection should prioritize breakthroughs in rapid detection technologies for internal and behind-the-structure defects.Efforts should also focus on developing multifunctional integrated detection vehicles that can simultaneously inspect both surface and internal structures.Furthermore,progress in fully automated,intelligent systems with precise defect identification and real-time reporting will be essential to significantly improve the efficiency and accuracy of tunnel inspection.
基金financially supported by the National Science Foundation of China(Nos.51974212 and 52274316)the China Baowu Low Carbon Metallurgy Innovation Foundation(No.BWLCF202116)+1 种基金the Science and Technology Major Project of Wuhan(No.2023020302020572)the Foundation of Key Laboratory for Ferrous Metallurgy and Resources Utilization of Ministry of Education(No.FMRUlab23-04)。
文摘The utilization of iron coke provides a green pathway for low-carbon ironmaking.To uncover the influence mechanism of iron ore on the behavior and kinetics of iron coke gasification,the effect of iron ore on the microstructure of iron coke was investigated.Furthermore,a comparative study of the gasification reactions between iron coke and coke was conducted through non-isothermal thermogravimetric method.The findings indicate that compared to coke,iron coke exhibits an augmentation in micropores and specific surface area,and the micropores further extend and interconnect.This provides more adsorption sites for CO_(2) molecules during the gasification process,resulting in a reduction in the initial gasification temperature of iron coke.Accelerating the heating rate in non-isothermal gasification can enhance the reactivity of iron coke.The metallic iron reduced from iron ore is embedded in the carbon matrix,reducing the orderliness of the carbon structure,which is primarily responsible for the heightened reactivity of the carbon atoms.The kinetic study indicates that the random pore model can effectively represent the gasification process of iron coke due to its rich pore structure.Moreover,as the proportion of iron ore increases,the activation energy for the carbon gasification gradually decreases,from 246.2 kJ/mol for coke to 192.5 kJ/mol for iron coke 15wt%.
基金sponsored by National Natural Science Foundation of China(No.52302121,No.52203386)Shanghai Sailing Program(No.23YF1454700)+1 种基金Shanghai Natural Science Foundation(No.23ZR1472700)Shanghai Post-doctoral Excellent Program(No.2022664).
文摘With vigorous developments in nanotechnology,the elaborate regulation of microstructure shows attractive potential in the design of electromagnetic wave absorbers.Herein,a hierarchical porous structure and composite heterogeneous interface are constructed successfully to optimize the electromagnetic loss capacity.The macro–micro-synergistic graphene aerogel formed by the ice template‑assisted 3D printing strategy is cut by silicon carbide nanowires(SiC_(nws))grown in situ,while boron nitride(BN)interfacial structure is introduced on graphene nanoplates.The unique composite structure forces multiple scattering of incident EMWs,ensuring the combined effects of interfacial polarization,conduction networks,and magnetic-dielectric synergy.Therefore,the as-prepared composites present a minimum reflection loss value of−37.8 dB and a wide effective absorption bandwidth(EAB)of 9.2 GHz(from 8.8 to 18.0 GHz)at 2.5 mm.Besides,relying on the intrinsic high-temperature resistance of SiC_(nws) and BN,the EAB also remains above 5.0 GHz after annealing in air environment at 600℃ for 10 h.
文摘To expand the study on the structures and biological activities of the anthracyclines anticancer drugs and reduce their toxic side effects,the new anthraquinone derivatives,9‑pyridylanthrahydrazone(9‑PAH)and 9,10‑bispyridylanthrahydrazone(9,10‑PAH)were designed and synthesized.Utilizing 9‑PAH and 9,10‑PAH as promising anticancer ligands,their respective copper complexes,namely[Cu(L1)Cl_(2)]Cl(1)and{[Cu_(4)(μ_(2)‑Cl)_(3)Cl_(4)(9,10‑PAH)_(2)(DMSO)_(2)]Cl_(2)}_(n)(2),were subsequently synthesized,where the new ligand L1 is formed by coupling two 9‑PAH ligands in the coordination reaction.The chemical and crystal structures of 1 and 2 were elucidated by IR,MS,elemental analysis,and single‑crystal X‑ray diffraction.Complex 1 forms a mononuclear structure.L1 coordinates with Cu through its three N atoms,together with two Cl atoms,to form a five‑coordinated square pyramidal geometry.Complex 2 constitutes a polymeric structure,wherein each structural unit centrosymmetrically encompasses two five‑coordinated binuclear copper complexes(Cu1,Cu2)of 9,10‑PAH,with similar square pyramidal geometry.A chlorine atom(Cl_(2)),located at the symmetry center,bridges Cu1 and Cu1A to connect the two binuclear copper structures.Meanwhile,the two five‑coordinated Cu2 atoms symmetrically bridge the adjacent structural units via one coordinated Cl atom,respectively,thus forming a 1D chain‑like polymeric structure.In vitro anticancer activity assessments revealed that 1 and 2 showed significant cytotoxicity even higher than cisplatin.Specifically,the IC_(50)values of 2 against HeLa‑229 and SK‑OV‑3 cancer cell lines were determined to be(5.92±0.32)μmol·L^(-1)and(6.48±0.39)μmol·L^(-1),respectively.2 could also block the proliferation of HeLa‑229 cells in S phase and significantly induce cell apoptosis.In addition,fluorescence quenching competition experiments suggested that 2 might interact with DNA by an intercalative binding mode,offering insights into its underlying anticancer mechanism.CCDC:2388918,1;2388919,2.
基金National Natural Science Foundation of China(U22A20191)。
文摘Brazing filler metals are widely applied,which serve as an industrial adhesive in the joining of dissimilar structures.With the continuous emergence of new structures and materials,the demand for novel brazing filler metals is ever-increasing.It is of great significance to investigate the optimized composition design methods and to establish systematic design guidelines for brazing filler metals.This study elucidated the fundamental rules for the composition design of brazing filler metals from a three-dimensional perspective encompassing the basic properties of applied brazing filler metals,formability and processability,and overall cost.The basic properties of brazing filler metals refer to their mechanical properties,physicochemical properties,electromagnetic properties,corrosion resistance,and the wettability and fluidity during brazing.The formability and processability of brazing filler metals include the processes of smelting and casting,extrusion,rolling,drawing and ring-making,as well as the processes of granulation,powder production,and the molding of amorphous and microcrystalline structures.The cost of brazing filler metals corresponds to the sum of materials value and manufacturing cost.Improving the comprehensive properties of brazing filler metals requires a comprehensive and systematic consideration of design indicators.Highlighting the unique characteristics of brazing filler metals should focus on relevant technical indicators.Binary or ternary eutectic structures can effectively enhance the flow spreading ability of brazing filler metals,and solid solution structures contribute to the formability.By employing the proposed design guidelines,typical Ag based,Cu based,Zn based brazing filler metals,and Sn based solders were designed and successfully applied in major scientific and engineering projects.
基金Key Research and Development Plan of Shaanxi Province(2023-YBGY-493)。
文摘As-forged WSTi6421 titanium alloy billet afterβannealing was investigated.Abnormally coarse grains larger than adjacent grains could be observed in the microstructures,forming abnormal grain structures with uneven size distribution.Through electron backscattered diffraction(EBSD),the forged microstructure at various locations of as-forged WSTi6421 titanium alloy billet was analyzed,revealing that the strength of theβphase cubic texture generated by forging significantly influences the grain size afterβannealing.Heat treatment experiments were conducted within the temperature range from T_(β)−50°C to T_(β)+10°C to observe the macro-and micro-morphologies.Results show that the cubic texture ofβphase caused by forging impacts the texture of the secondaryαphase,which subsequently influences theβphase formed during the post-βannealing process.Moreover,the pinning effect of the residual primaryαphase plays a crucial role in the growth ofβgrains during theβannealing process.EBSD analysis results suggest that the strength ofβphase with cubic texture formed during forging process impacts the orientation distribution differences ofβgrains afterβannealing.Additionally,the development of grains with large orientations within the cubic texture shows a certain degree of selectivity duringβannealing,which is affected by various factors,including the pinning effect of the primaryαphase,the strength of the matrix cubic texture,and the orientation relationship betweenβgrain and matrix.Comprehensively,the stronger the texture in a certain region,the less likely the large misoriented grains suffering secondary growth,thereby aggregating the difference in microstructure and grain orientation distribution across different regions afterβannealing.
文摘It is of great scientific significance to construct a 3D dynamic structural color with a special color effect based on the microlens array.However,the problems of imperfect mechanisms and poor color quality need to be solved.A method of 3D structural color turning on periodic metasurfaces fabricated by the microlens array and self-assembly technology was proposed in this study.In the experiment,Polydimethylsiloxane(PDMS)flexible film was used as a substrate,and SiO2 microspheres were scraped into grooves of the PDMS film to form 3D photonic crystal structures.By adjusting the number of blade-coated times and microsphere concentrations,high-saturation structural color micropatterns were obtained.These films were then matched with microlens arrays to produce dynamic graphics with iridescent effects.The results showed that by blade-coated two times and SiO2 microsphere concentrations of 50%are the best conditions.This method demonstrates the potential for being widely applied in the anticounterfeiting printing and ultra-high-resolution display.
基金supported by the Surface Project of Local De-velopment in Science and Technology Guided by Central Govern-ment(No.2021ZYD0041)the National Natural Science Founda-tion of China(Nos.52377026 and 52301192)+3 种基金the Natural Science Foundation of Shandong Province(No.ZR2019YQ24)the Taishan Scholars and Young Experts Program of Shandong Province(No.tsqn202103057)the Special Financial of Shandong Province(Struc-tural Design of High-efficiency Electromagnetic Wave-absorbing Composite Materials and Construction of Shandong Provincial Tal-ent Teams)the“Sanqin Scholars”Innovation Teams Project of Shaanxi Province(Clean Energy Materials and High-Performance Devices Innovation Team of Shaanxi Dongling Smelting Co.,Ltd.).
文摘With the increasing complexity of the current electromagnetic environment,excessive microwave radi-ation not only does harm to human health but also forms various electromagnetic interference to so-phisticated electronic instruments.Therefore,the design and preparation of electromagnetic absorbing composites represent an efficient approach to mitigate the current hazards of electromagnetic radiation.However,traditional electromagnetic absorbers are difficult to satisfy the demands of actual utilization in the face of new challenges,and emerging absorbents have garnered increasing attention due to their structure and performance-based advantages.In this review,several emerging composites of Mxene-based,biochar-based,chiral,and heat-resisting are discussed in detail,including their synthetic strategy,structural superiority and regulation method,and final optimization of electromagnetic absorption ca-pacity.These insights provide a comprehensive reference for the future development of new-generation electromagnetic-wave absorption composites.Moreover,the potential development directions of these emerging absorbers have been proposed as well.
基金supported by the National Natural Science Foundation of China(Nos.62101020 and 62141405)the Special Scientific Research Project of Civil Aircraft,China(No.MJZ5-2N22).
文摘As the proportion of composite materials used in aircraft continues to increase, the electromagnetic Shielding Effectiveness (SE) of these materials becomes a critical factor in the electromagnetic safety design of aircraft structures. The assessment of electromagnetic SE for Slotted Composite Structures(SCSs) is particularly challenging due to their complex geometries and there remains a lack of suitable models for accurately predicting the SE performance of these intricate configurations. To address this issue, this paper introduces SCS-Net, a Deep Neural Network (DNN) method designed to accurately predict the SE of SCS. This method considers the impacts of various structural parameters, material properties and incident wave parameters on the SE of SCSs. In order to better model the SCS, an improved Nicolson-Ross-Weir (NRW) method is introduced in this paper to provide an equivalent flat structure for the SCS and to calculate the electromagnetic parameters of the equivalent structure. Additionally, the prediction of SE via DNNs is limited by insufficient test data, which hinders support for large-sample training. To address the issue of limited measured data, this paper develops a Measurement-Computation Fusion (MCF) dataset construction method. The predictions based on the simulation results show that the proposed method maintains an error of less than 0.07 dB within the 8–10 GHz frequency range. Furthermore, a new loss function based on the weighted L1-norm is established to improve the prediction accuracy for these parameters. Compared with traditional loss functions, the new loss function reduces the maximum prediction error for equivalent electromagnetic parameters by 47%. This method significantly improves the prediction accuracy of SCS-Net for measured data, with a maximum improvement of 23.88%. These findings demonstrate that the proposed method enables precise SE prediction and design for composite structures while reducing the number of test samples needed.
基金sponsored by the National Natural Science Foundation of China(Nos.5210125 and 52375422)the Science Research Project of Hebei Education Department(No.BJK2023058)the Natural Science Foundation of Hebei Province(Nos.E2020208069,B2020208083 and E202320801).
文摘The stability and electrocatalytic efficiency of transition metal oxides for water splitting is determined by geometric and electronic structure,especially under high current densities.Herein,a newly designed lamella-heterostructured nanoporous CoFe/CoFe_(2)O_(4) and CeO_(2−x),in situ grown on nickel foam(NF),holds great promise as a high-efficient bifunctional electrocatalyst(named R-CoFe/Ce/NF)for water splitting.Experimental characterization verifies surface reconstruction from CoFe alloy/oxide to highly active CoFeOOH during in situ electrochemical polarization.By virtues of three-dimensional nanoporous architecture and abundant electroactive CoFeOOH/CeO_(2−x) heterostructure interfaces,the R-CoFe/Ce/NF electrode achieves low overpotentials for oxygen evolution(η_(10)=227 mV;η_(500)=450 mV)and hydrogen evolution(η_(10)=35 mV;η_(408)=560 mV)reactions with high normalized electrochemical active surface areas,respectively.Additionally,the alkaline full water splitting electrolyzer of R-CoFe/Ce/NF||R-CoFe/Ce/NF achieves a current density of 50 mA·cm^(−2) only at 1.75 V;the decline of activity is satisfactory after 100-h durability test at 300 mA·cm^(−2).Density functional theory also demonstrates that the electron can transfer from CeO_(2−x) by virtue of O atom to CoFeOOH at CoFeOOH/CeO_(2−x) heterointerfaces and enhancing the adsorption of reactant,thus optimizing electronic structure and Gibbs free energies for the improvement of the activity for water splitting.
基金supported by the National Key R&D Program of China(Nos.2023YFE0108300 and 2023YFD2202103)the National Natural Science Foundation of China(No.32371972)+2 种基金the Natural Science Foundation of Jiangsu Province,China(No.BK20221336)Jiangsu Agricultural Science and Technology Independent Innovation Fund,China(No.CX(23)3060)Jiangxi Forestry Bureau Forestry Science and Technology Innovation Special Project,China(No.202240).
文摘The rapid development of 5G communication technology and smart electronic and electrical equipment will inevitably lead to electromagnetic radiation pollution.Enriching heterointerface polarization relaxation through nanostructure design and interface modifica-tion has proven to be an effective strategy to obtain efficient electromagnetic wave absorption.Here,this work implements an innovative method that combines biomimetic honeycomb superstructure to constrain hierarchical porous heterostructure composed of Co/CoO nano-particles to improve the interfacial polarization intensity.The method effectively controlled the absorption efficiency of Co^(2+)through de-lignification modification of bamboo,and combined with the bionic carbon-based natural hierarchical porous structure to achieve uniform dispersion of nanoparticles,which is conducive to the in-depth construction of heterogeneous interfaces.In addition,the multiphase struc-ture brought about by high-temperature pyrolysis provides the best dielectric loss and impedance matching for the material.Therefore,the obtained bamboo-based Co/CoO multiphase composite showed excellent electromagnetic wave absorption performance,achieving excel-lent reflection loss(RL)of-79 dB and effective absorption band width of 4.12 GHz(6.84-10.96 GHz)at low load of 15wt%.Among them,the material’s optimal radar cross-section(RCS)reduction value can reach 31.9 dB·m^(2).This work provides a new approach to the micro-control and comprehensive optimization of macro-design of microwave absorbers,and offers new ideas for the high-value utiliza-tion of biomass materials.
基金supported by the National Nature Science Foundation of China(Nos.22305066 and 52372041).
文摘High-temperature microwave absorbing materials(MAMs)and structures are increasingly appealing due to their critical role in stealth applications under harsh environments.However,the impedance mismatch caused by increased conduction loss often leads to a significant decline in electromagnetic wave absorp-tion(EMWA)performance at elevated temperatures,which severely restricts their practical application.In this study,we propose a novel approach for efficient electromagnetic wave absorption across a wide temperature range using reduced graphene oxide(RGO)/epoxy resin(EP)metacomposites that integrate both electromagnetic parameters and metamaterial design concepts.Due to the discrete distribution of the units,electromagnetic waves can more easily penetrate the interior of materials,thereby exhibiting stable microwave absorption(MA)performance and impedance-matching characteristics suitable across a wide temperature range.Consequently,exceptional MA properties can be achieved within the tem-perature range from 298 to 473 K.Furthermore,by carefully controlling the structural parameters in RGO metacomposites,both the resonant frequency and effective absorption bandwidth(EAB)can be optimized based on precise manipulation of equivalent electromagnetic parameters.This study not only provides an effective approach for the rational design of MA performance but also offers novel insights into achieving super metamaterials with outstanding performance across a wide temperature spectrum.
基金supported by PTDC-01778/2022-NeuroDev3D,iNOVA4Health(UIDB/04462/2020 and UIDP/04462/2020)LS4FUTURE(LA/P/0087/2020)。
文摘Cells,tissues,and organs are constantly subjected to the action of mechanical forces from the extracellular environment-and the nervous system is no exception.Cell-intrinsic properties such as membrane lipid composition,abundance of mechanosensors,and cytoskeletal dynamics make cells more or less likely to sense these forces.Intrinsic and extrinsic cues are integrated by cells and this combined information determines the rate and dynamics of membrane protrusion growth or retraction(Yamada and Sixt,2019).Cell protrusions are extensions of the plasma membrane that play crucial roles in diverse contexts such as cell migration and neuronal synapse formation.In the nervous system,neurons are highly dynamic cells that can change the size and number of their pre-and postsynaptic elements(called synaptic boutons and dendritic spines,respectively),in response to changes in the levels of synaptic activity through a process called plasticity.Synaptic plasticity is a hallmark of the nervous system and is present throughout our lives,being required for functions like memory formation or the learning of new motor skills(Minegishi et al.,2023;Pillai and Franze,2024).
基金supported by the Natural Science Foundation of Shanxi Province(Nos.20210302123015 and 20210302123035)the Opening Project of State Key Laboratory of Polymer Materials Engineering(Sichuan University)(No.sklpme2022-4-06)the Open Foundation of China-Belarus Belt and Road Joint Laboratory on Electromagnetic Environment Effect(No.ZBKF2022030301).
文摘In the present work,by virtue of the synergistic and independent effects of Janus structure,an asymmetric nickel-chain/multiwall carbon nanotube/polyimide(Ni/MWCNTs/PI)composite foam with absorption-dominated electromagnetic interference(EMI)shielding and thermal insulation performances was successfully fabricated through an ordered casting and directional freeze-drying strategy.Water-soluble polyamic acid(PAA)was chosen to match the oriented freeze-drying method to acquire oriented pores,and the thermal imidization process from PAA to PI exactly eliminated the interface of the multilayered structure.By controlling the electro-magnetic gradient and propagation path of the incident microwaves in the MWCNT/PI and Ni/PI layers,the PI composite foam exhibited an efficient EMI SE of 55.8 dB in the X-band with extremely low reflection characteristics(R=0.22).The asymmetric conductive net-work also greatly preserved the thermal insulation properties of PI.The thermal conductivity(TC)of the Ni/MWCNT/PI composite foam was as low as 0.032 W/(m K).In addition,owing to the elimination of MWCNT/PI and Ni/PI interfaces during the thermal imidization process,the composite foam showed satisfactory compressive strength.The fabricated PI composite foam could provide reliable electromagnetic protection in complex applications and withstand high temperatures,which has great potential in cuttingedge applications such as advanced aircraft.
基金financially supported by the National Natural Science Foundation of China(Nos.52233001,51927805,and 52173110)the Innovation Program of Shanghai Municipal Education Commission(No.2023ZKZD07)the Shanghai Rising-Star Program(No.22QA1401200)。
文摘Cholesteric liquid crystals(CLCs)exhibit unique helical superstructures that selectively reflect circularly polarized light,enabling them to dynamically respond to environmental changes with tunable structural colors.This dynamic color-changing capability is crucial for applications that require adaptable optical properties,positioning CLCs as key materials in advanced photonic technologies.This review focuses on the mechanisms of dynamic color tuning in CLCs across various forms,including small molecules,cholesteric liquid crystal elastomers(CLCEs),and cholesteric liquid crystal networks(CLCNs),and emphasizes the distinct responsive coloration each structure provides.Key developments in photochromic mechanisms based on azobenzene,dithienylethene,and molecular motor switches,are discussed for their roles in enhancing the stability and tuning range of CLCs.We examine the color-changing behaviors of CLCEs under mechanical stimuli and CLCNs under swelling,highlighting the advantages of each form.Following this,applications of dynamic color-tuning CLCs in information encryption,adaptive camouflage,and smart sensing technologies are explored.The review concludes with an outlook on current challenges and future directions in CLC research,particularly in biomimetic systems and dynamic photonic devices,aiming to broaden their functional applications and impact.
