The development of materials with excellent microwave absorption(MWA)and electromagnetic interference(EMI)shielding performances has currently received attention.Herein,mesophase pitch-based carbon foam(MPCF)with 3D i...The development of materials with excellent microwave absorption(MWA)and electromagnetic interference(EMI)shielding performances has currently received attention.Herein,mesophase pitch-based carbon foam(MPCF)with 3D interconnected pore structure was prepared through the high pressure pyrolysis of mesophase coal tar pitch.It is found that the 3D interconnected cellular pores of MPCF facilitate multiple reflections of electromagnetic waves,which results in the minimum reflection loss(RLmin)value of MPCF reaches-37.84 dB with the effective absorption bandwidth(EAB)of 5.44 GHz at a thickness of 2.70 mm,and the total average electromagnetic shielding effectiveness(SE_(T))under 3.00 mm thickness achieves 26.52 dB in X-band.Subsequently,MPCF is activated by KOH to obtain activated carbon foam(A-MPCF).The average SE_(T)of A-MPCF achieves 103.00 dB for abundant nanopores on the pore cell walls,which leads to a transition from the multiple reflections of electromagnetic waves on the walls to diffuse reflection.Unfortunately,the reflection coefficient(R)of A-MPCF increases from 0.78 to 0.90.To reduce the R value,Fe_(3)O_(4)/A-MPCF was fabricated via the in situ growth of nano Fe_(3)O_(4)on A-MPCF.Consequently,the R value of Fe_(3)O_(4)/A-MPCF was reduced from 0.90 to 0.74,whereas the MWA performance was only slightly decreased.This work proposes a simple strategy for simultaneously adjusting MWA and EMI shielding performances of materials.展开更多
The multi-satellite electromagnetic formation flight system is nonlinear and strongly coupled,which makes modeling and optimization challenging.To simplify electromagnetic force evaluation and dynamics modeling,we int...The multi-satellite electromagnetic formation flight system is nonlinear and strongly coupled,which makes modeling and optimization challenging.To simplify electromagnetic force evaluation and dynamics modeling,we introduce a reference frame consistent with each satellite body frame,in which the electromagnetic dipoles and electromagnetic forces are represented as two-dimensional vectors.Then,the maneuver time is divided into time intervals,and different satellite sets are activated in each interval,converting the multi-satellite formation reconfiguration problem into an optimal trajectory problem of each two-satellite subsystem.To this end,a token-based dynamic programming method with a switching penalty of active satellite sets is proposed to determine the sequence of satellite sets participating in each time interval,thereby enabling all satellites to reach their desired states.For the two-satellite subsystem with the objectives of minimizing maneuver time and energy consumption,the Gauss pseudo-spectral method is employed to generate the optimal reconfiguration trajectory.Numerical simulations verify the effectiveness of the proposed optimization method.展开更多
This study investigates prescribed-time position tracking control for electromagnetic satellite formations subject to model uncertainties and external disturbances.Using the Clohessy-Wiltshire equations as the relativ...This study investigates prescribed-time position tracking control for electromagnetic satellite formations subject to model uncertainties and external disturbances.Using the Clohessy-Wiltshire equations as the relative motion dynamics model,a prescribed time output feedback control strategy is proposed.A prescribed-time extended state observer is designed to estimate the relative velocity and external disturbances.The disturbance estimates are then used as the feedforward component of the controller.Building on this framework,a novel prescribed-time active disturbance rejection control strategy for position tracking is developed via a backstepping control design.The convergence of the extended state observer and the stability of the closed-loop system are rigorously analyzed using Lyapunov stability theory.Numerical simulations are performed to validate the effectiveness of the proposed controller.展开更多
Biochar and biochar composites are versatile materials that can be used in many applications.In this study,biochar was prepared from sawdust and combined with the yttrium iron garnet(YIG)nanocrystal to investigate the...Biochar and biochar composites are versatile materials that can be used in many applications.In this study,biochar was prepared from sawdust and combined with the yttrium iron garnet(YIG)nanocrystal to investigate the shielding effectiveness of the composite structure.Firstly,the effect of the pyrolysis temperature on the shielding effectiveness of biochar was investigated.Secondly,biochars combined with YIG nanocrystals with different contents and shielding effectiveness of the composites were investigated.The electromagnetic effectiveness of the samples was investigated within the X band(8-12 GHz).The findings indicate that biochar demonstrates enhanced absorption properties with elevated pyrolysis temperatures.Biochars demonstrated an approximate 40 d B shielding effectiveness,while YIG exhibited approximately 7 d B,corresponding to absorption at 8 GHz.However,the combination of biochar and YIG exhibited exceptional absorption,reaching 67.12 d B at 8 GHz.展开更多
A methodology for the reduction of radar cross section(RCS)of cambered platforms within the target airspace is presented,which utilizes a dual-polarized ultra-wide-angle artificial electromagnetic absorbing surface.By...A methodology for the reduction of radar cross section(RCS)of cambered platforms within the target airspace is presented,which utilizes a dual-polarized ultra-wide-angle artificial electromagnetic absorbing surface.By applying the theory of generalized Brewster complex wave impedance matching,five distinct unit cell designs are developed to attain more than95%absorption rate for dual-polarized incident waves within five angular ranges:0°-30°,30°-50°,50°-60°,60°-70°,and 70°-80°.To optimally reduce the RCS of a cambered platform,the five types of units can be evenly distributed on the surface based on the local incident angles of plane waves originating from the target airspace.As an illustrative example,the leading edge of an airfoil is taken into account,and experimental measurements validate the efficiency of the proposed structure.Specifically,the absorbing surface achieves more than 10 dB of RCS reduction in the frequency ranges from 5-10 GHz(about66.7%relative bandwidth)for dual polarizations.展开更多
Transient electromagnetic methods are increasingly adopted for field investigation of oil pollution because they provide rapid,non-invasive imaging of subsurface electrical conductivity across depths relevant to vados...Transient electromagnetic methods are increasingly adopted for field investigation of oil pollution because they provide rapid,non-invasive imaging of subsurface electrical conductivity across depths relevant to vadose-zone impacts,groundwater plumes,and coastal transition zones.This review synthesizes recent advances that have expanded TEM(Transient Electromagnetic Method)’s environmental applicability,including higher dynamic range receivers,multi-moment acquisition that improves shallow-to-deep sensitivity,and diversified deployment platforms spanning ground,mobile/towed,airborne,and coastal/marine configurations,with emerging UAV(Unmanned Aerial Vehicle)options for constrained access.We emphasize the electrical and geochemical basis of hydrocarbon-related signatures,showing why fresh releases may appear resistive through NAPL(Non-Aqueous Phase Liquid)displacement of conductive pore water,whereas aged contamination often produces conductive responses driven by biodegradation,redox evolution,and elevated ionic strength.Because these responses are non-unique and can be confounded by clay-rich lithology,salinity gradients,temperature variability,and cultural infrastructure,contemporary interpretation has shifted toward process-consistent conceptual site models and uncertainty-aware products that communicate depth of investigation and resolution limits.A thematic synthesis of field applications indicates TEM is most reliable for mapping hydrogeological architecture,delineating plausible plume corridors,prioritizing intrusive sampling,and supporting monitoring where repeatability and background variability are controlled.The review concludes that TEM delivers the greatest decision value when integrated in a weight-of-evidence framework with hydrogeology,geochemistry,and targeted ground truth,and it highlights future needs in standardized reporting,robust time-lapse appraisal,and stronger petrophysical links to hydrocarbon transformation.展开更多
With the rapid development of intelligent electronic and military equipment,multifunctional flexible materials that integrat electromagnetic interference(EMI)shielding,temperature sensing,and information encryption ar...With the rapid development of intelligent electronic and military equipment,multifunctional flexible materials that integrat electromagnetic interference(EMI)shielding,temperature sensing,and information encryption are urgently required.This study presents a bio-inspired hierarchical composite foam fabricated using supercritical nitrogen foaming technology.This material exhibits a honeycomb structure,with pore cell sizes controllable within a range of 30–92μm by regulating the filler.The carbon fiber felt(CFf)provides efficient reflection of electromagnetic waves,while the chloroprene rubber/carbon fiber/carbon black foam facilitates both wave absorption and temperature monitoring through its optimized conductive network.This synergistic mechanism results in an EMI shielding effectiveness(SE)of 60.06 d B with excellent temperature sensing performance(The temperature coefficient of resistance(TCR)is-2.642%/℃)in the 24–70℃ range.Notably,the material has a thermal conductivity of up to 0.159 W/(m·K),and the bio-inspired layered design enables information encryption,demonstrating the material's potential for secure communication applications.The foam also has tensile properties of up to 5.13 MPa and a tear strength of 33.02 N/mm.This biomimetic design overcomes the traditional limitations of flexible materials and provides a transformative solution for next-generation applications such as flexible electronics,aerospace systems and military equipment,which urgently need integrated electromagnetic protection,thermal management and information security.展开更多
The advancement of next-generation high-frequency communication systems and stealth detection technologies necessitate the development of efficient,multi-spectrum compatible shielding materials.However,the achievement...The advancement of next-generation high-frequency communication systems and stealth detection technologies necessitate the development of efficient,multi-spectrum compatible shielding materials.However,the achievement of simultaneous high efficiency and low reflectivity across microwave,terahertz,and infrared spectra remains a formidable challenge.Herein,a carbonized MXene/polyimide(C-MXene/PI)aerogel material integrating a spatially coupled hierarchically anisotropic structure with stepwise conductivity gradients was constructed.Electromagnetic waves propagate through the top-down vertical disordered horizontal architecture and progressive conductivity gradient of C-MXene/PI aerogel,undergoing stepwise absorption-dissipation-re-dissipation processes.The C-MXene/PI aerogel exhibits an average electromagnetic interference(EMI)shielding effectiveness of91.0 dB in X-band and a reflection coefficient of 0.40.In the terahertz frequency band,the average EMI shielding performance reaches66.2 dB with a reflection coefficient of 0.33.Furthermore,the heterolayered porous architecture of C-MXene/PI aerogels exhibits low thermal conductivity and reduced infrared emissivity,enabling exceptional infrared stealth capability across the 2-16μm wavelength spectrum.This study provides an feasible strategy for constructing low-reflectivity multi-spectrum compatible shielding materials.展开更多
A three-dimensional(3D)electromagnetic(EM)inversion algorithm based on the nonlinear conjugate gradient(NLCG)method and a two-color plane Gauss-Seidel(GS)multigrid(MG)forward solver is developed to improve inversion e...A three-dimensional(3D)electromagnetic(EM)inversion algorithm based on the nonlinear conjugate gradient(NLCG)method and a two-color plane Gauss-Seidel(GS)multigrid(MG)forward solver is developed to improve inversion efficiency.The results indicate that the computational efficiency of each inversion can be improved by approximately a factor of three by using the proposed MG solver.First,the accuracy of the MG solver is validated through a test on a synthetic model.Next,the numerical performance of the inversion algorithm is evaluated using this model.Finally,the inversion algorithm is applied to a field EM data collected at the Beiya gold polymetallic ore district.A 3D resistivity model is obtained,and the formation process of the metal ore is analyzed.展开更多
In this study,an architecture featuring a gradient conductive network structure and three-dimensional dual-continuous network structure is constructed in a carbon nanotubes/cellulose-boron nitride/poly(vinyl alcohol)(...In this study,an architecture featuring a gradient conductive network structure and three-dimensional dual-continuous network structure is constructed in a carbon nanotubes/cellulose-boron nitride/poly(vinyl alcohol)(CNT/cellulose-BN/PVA)composite.Using cellulose aerogel as a template,CNT were incorporated into the cellulose template by vertically impregnating the CNT suspension.Following the impregnation of BN/PVA and high-pressure compression,three-dimensional dual-continuous network structure was successfully constructed in the CNT/cellulose-BN/PVA composite.The comprehensive performance of the composite,including electromagnetic interference(EMI)shielding and Joule heating performance,was investigated.The results indicate that the total EMI shielding effectiveness(SE)for the CNT/cellulose-BN/PVA composite reveals similar values for electromagnetic waves incident from different directions,but totally different shielding mechanisms.For the CNT/cellulose-BN/PVA composite with three impregnation cycles of CNT,the EMI SE values exceeded 39 dB for electromagnetic waves incident from both the high-and low-CNT-content sides.93%of the microwaves were reflected when electromagnetic waves were incident from the high-CNT-content side,while the reflection coefficient decreased to 0.44 for the transverse direction.In addition,the construction of the dual-continuous network structure enabled the composite to exhibit both excellent electrical conductivity and good thermal conductivity simultaneously,endowing the material with good Joule heating performance.CNT/cellulose-BN/PVA composite films have significant potential for application as EMI shielding materials in extremely cold weather.展开更多
A 3D mathematical model was established to investigate the gas-liquid two-phase flow in Ruhrstahl-Heraeus(RH)vacuum refining process.The flow characteristics of molten steel were calculated using the coupled standard...A 3D mathematical model was established to investigate the gas-liquid two-phase flow in Ruhrstahl-Heraeus(RH)vacuum refining process.The flow characteristics of molten steel were calculated using the coupled standard k-εmodel and volume of fluid model.The bubble distribution was tracked by discrete phase model.Electromagnetic field was applied in the up-leg snorkel to enhance the effect of vacuum refining.The effect of swirling flow nozzles combined with electromagnetic stirring(EMS)on the flow characteristics of molten steel and bubble distribution was analyzed.The erosion of the up-leg snorkel was compared.The results show that when the swirling flow nozzles are used,the bubbles exhibit a distinct adherent rising behavior,and the refining efficiency decreases.In addition,the electromagnetic field can significantly improve the refining efficiency,but it brings stronger erosion to the up-leg snorkel.Nevertheless,when using the swirling flow nozzles combined with EMS,the refining performance is further optimized,and the erosion of the up-leg snorkel is also reduced due to its characteristic of bubble distribution.Compared to conventional nozzles,the mixing time was shortened by 16.2%,the recirculation rate increased by 12.5%.and the swirling intensity was strengthened by 8.9%.展开更多
The electromagnetic wave absorption of silicon carbide nanowires is improved by their uniform and diverse cross-structures.This study introduces a sustainable and high value-added method for synthesizing silicon carbi...The electromagnetic wave absorption of silicon carbide nanowires is improved by their uniform and diverse cross-structures.This study introduces a sustainable and high value-added method for synthesizing silicon carbide nanowires using lignite and waste silicon powder as raw materials through carbothermal reduction.The staggered structure of nanowires promotes the creation of interfacial polarization,impedance matching,and multiple loss mechanisms,leading to enhanced electromagnetic absorption performance.The silicon carbide nanowires demonstrate outstanding electromagnetic absorption capabilities with the minimum reflection loss of-48.09 d B at10.08 GHz and an effective absorption bandwidth(the reflection loss less than-10 d B)ranging from 8.54 to 16.68 GHz with a thickness of 2.17 mm.This research presents an innovative approach for utilizing solid waste in an environmentally friendly manner to produce broadband silicon carbide composite absorbers.展开更多
To address increasing electromagnetic interference and pollution problems,this study proposes a component regulation strategy.Hollow magnetic microspheres derived from metal-organic frameworks(MOFs)were incorporated i...To address increasing electromagnetic interference and pollution problems,this study proposes a component regulation strategy.Hollow magnetic microspheres derived from metal-organic frameworks(MOFs)were incorporated into carbon fibers(Co@CNFs)through electrospinning technology,forming a sugar-gourd-like heterostructure.This structure promotes the synergy between dielectric and magnetic losses.The full utilization of multi-component synergy and the well-designed heterogeneous interfaces enhances interfacial polarization and optimizes the balance between impedance and high loss.The hollow structure of magnetic microspheres facilitates multiple scattering of electromagnetic waves(EMW).Additionally,the change of heat treatment temperature offers a viable method to adjust the dielectric properties of composites.The results indicate that the Co@CNFs exhibit outstanding EMW attenuation capability,even at an ultralow filler loading of 3 wt%,achieving a reflection loss of-39.7 dB and an effective absorption bandwidth of 7.6 GHz.This study demonstrates the effectiveness of component regulation and offers a viable approach for lightweight,high-performance EMW absorption materials.展开更多
To shield electronics from complicated electromagnetic environments caused by wireless electromagnetic waves,achieving elaborately structural manufacturing while not sacrificing electromagnetic interference shielding ...To shield electronics from complicated electromagnetic environments caused by wireless electromagnetic waves,achieving elaborately structural manufacturing while not sacrificing electromagnetic interference shielding performances remains crucial challenges.Herein,we propose a hierarchical manufacturing method that combines the use of 3D printing shear flow field and layer-by-layer assembly for fabricating the structurally customizable and multifunctional polylactic acid@graphene nanoparticle(PLA@GNs)materials.The dynamic behavior of polymer fluids is firstly explored via computational fluid dynamic simulation,and a Weissenberg number is employed to quantitatively analyze the disordered-to-ordered structural evolution of molecular chains and nanoparticles,allowing to tailor the micro-scale ordered structures.Subsequently,the macro-scale 3D architectures of PLA@GNs modules are fabricated by layer-by-layer assembly.Owing to the aligned GNs,the shielding performance reaches 41.2 d B,simultaneously accompanied by a directional thermal conductivity of 3.2 W m^(-1)K^(-1).Moreover,the potential application of 3D-printed shielding modules in specific civilian frequency bands such as 4G(1800–2100 MHz),Bluetooth(2402–2480 MHz),and 5G(3300–3800 MHz)is fully demonstrated.Overall,this work not only establishes a universal methodology about 3D printing shear flow field-driven orientation of two-dimensional nanoparticles within polymer fluids,but also gives a scientific method for advanced manufacturing of the next-generation electromagnetic functional modules for smart electronics.展开更多
How to transform an electromagnetic field across non-inertial frames of reference is a common challenge encountered in electromagnetic space measurements and analyses.Finding clear and precise ways to evaluate transfo...How to transform an electromagnetic field across non-inertial frames of reference is a common challenge encountered in electromagnetic space measurements and analyses.Finding clear and precise ways to evaluate transformation formulas can be difficult.This study presents results of a thorough theoretical investigation that has yielded universal transformation formulas;these transformations are successfully applied to two specific scenarios.We find that,for space plasmas,if the relative velocities of structures are significantly lower than the speed of light,Galilean transformations are suitable.The transformations presented in this paper are applicable,in low speed situations,to electromagnetic fields,electric potentials and magnetic vector potentials,and to charge density and current density,measured in various non-inertial reference frames.Truncation errors associated with these simplified transformations are calculated and shown to be acceptable.These findings have broad implications for space physics measurements and analyses.We address two key issues related to non-inertial frame transformations:first,how to derive a general formula for the rotational electric potential of planets with intrinsic magnetic fields;second,how to verify rigorously the calculation of charge density from MMS(Magnetospheric Multiscale)electrostatic field measurements.We suggest that,due to the validity of the Coulomb gauge,the Poisson equation can be applied in situations of low-speed motion,allowing MMS measurement data to be used to calculate minimal-error charge density.展开更多
The rapid development of electronic devices and communication technologies has resulted in increasingly severe electromagnetic-wave(EW)pollution.Efficient EW absorption(EWA)materials are essential to mitigate their im...The rapid development of electronic devices and communication technologies has resulted in increasingly severe electromagnetic-wave(EW)pollution.Efficient EW absorption(EWA)materials are essential to mitigate their impact and ensure human safety in modern society.Fe-based EWA materials have garnered significant attention owing to their cost-effectiveness,high saturation magnetization,and superior magnetic loss capabilities.This review begins with an introduction to Fe-based EWA materials,followed by a brief description of their EWA mechanisms.Various pristine Fe-based absorbers,such as carbonyl iron powder,ferrite-based materials,Fe-based alloys,Fe-based high-entropy alloys(HEAs),and Fe-based layered ternary transition-metal borides,have been systematically reviewed.Key strategies to enhance the performance of Fe-based composite absorbers,including doping,in-situ oxidation,porous structuring,and composite construction,are critically discussed.Finally,the review presents a summary and future perspectives in this field,highlighting the synergy between Fe-based and high-entropy materials in advancing next-generation EWA for applications in stealth technology,wear-able electronics,and harsh environments.展开更多
With the increasing requirements of electromagnetic wave(EMW)absorption,developing EMW absorbers with high-efficiency anti-corrosion performance which can be effectively applied in extreme corrosive environments is im...With the increasing requirements of electromagnetic wave(EMW)absorption,developing EMW absorbers with high-efficiency anti-corrosion performance which can be effectively applied in extreme corrosive environments is imperative and constitutes a hot issue in the current research.Herein,based on the composition modulation of ZrO_(2)and SiO_(2)layer,the dual-oxides confined carbonyl iron(CI@ZrO_(2)/SiO_(2))composite displays a minimum reflection loss(RLmin)of-48.58 dB@1.9 mm and an effective absorption bandwidth(EAB)of 7.62 GHz@1.6 mm.Besides,the CI@ZrO_(2)/SiO_(2)displays superior corrosion resistance with corrosion current density(i_(corr))of 8.62×10^(-7)A/cm^(2)and polarization resistance(Rp)of 3.64×10^(5)Ω.This work proposes a strategy to optimize the broadband EMW absorption properties as well as the mass production toward the corrosion resistance applications.展开更多
Three-dimensional(3D)-printedgraphene aerogels hold promise for electromagneticwave absorption(EWA)engineering due to itsultralow density,outstanding electromagnetic dissipationwith the flexibility and precision of ma...Three-dimensional(3D)-printedgraphene aerogels hold promise for electromagneticwave absorption(EWA)engineering due to itsultralow density,outstanding electromagnetic dissipationwith the flexibility and precision of manufacturingstrategies.However,their high conductivitycauses severe impedance mismatch,limiting EWAperformance.3D printing requirements also constrainthe dielectric properties of printable grapheneinks,hindering the integration of high-performanceabsorbers with advanced manufacturing.This studyproposes a polyacrylic acid(PAA)gel-mediated3D porous graphene oxide(GO)aerogel multiscaleregulation strategy.Precise gel content control enablesdual-gradient tuning of the rheology(Benefitingdirect ink writing(DIW))and dielectric loss(Enhancing EWA)of GO/PAA composites and reduces aerogel density(6.9 mg cm^(-3)from28.2 mg cm^(-3)).Thermal reduction decomposes PAA into amorphous carbon nanoparticles anchored on reduced graphene oxide(rGO),enhancingimpedance matching and absorption via synergistic 0D/2D interfacial polarization and conductive loss.The optimized rGO/PAA aerogelachieves a minimum reflection loss(RL)of-39.86 dB at 2.5 mm and an effective absorption bandwidth(EAB)of 8.36 GHz(9.64-18 GHz)at3.2 mm.Combining DIW and this aerogel,we design a metamaterial absorber(MA)with dual material(dielectric loss)and structural gradients.This MA exhibits an ultrawide EAB of 14 GHz(4-18 GHz)with a total thickness of 7.8 mm.This work establishes a coupled design paradigmof“composition-structure-performance,”providing an engineerable solution for developing lightweight,broadband EWA materials.展开更多
The development of multifunctional electromagnetic wave-absorbing materials is essential for next-generation flexible electronics and intelligent protection systems.Herein,a novel three-dimensional porous MXene-based ...The development of multifunctional electromagnetic wave-absorbing materials is essential for next-generation flexible electronics and intelligent protection systems.Herein,a novel three-dimensional porous MXene-based film integrated with metallic nickel nanoparticles(Ni-PMF)is designed and synthesized with the potential to address the urgent need for multifunctional electromagnetic wave-absorbing materials in next-generation intelligent systems.By using polystyrene spheres as sacrificial templates,a hierarchical porous architecture is constructed to prevent MXene nanosheet restacking,extend electromagnetic wave propagation paths,and optimize impedance matching.Simultaneously,uniformly distributed Ni nanoparticles introduce abundant heterogeneous interfaces,enhancing interfacial polarization and magnetic loss,which significantly improve electromagnetic wave attenuation.The Ni-PMF film achieves a minimum reflection loss of–64.7 d B and a broad effective absorption bandwidth of 7.2 GHz,covering the full Ku-band and outperforming most reported MXene thin film absorbers.In addition to superior electromagnetic wave absorption,the film demonstrates excellent electrothermal conversion and flexible strain-sensing capabilities,enabling integrated protection and real-time sensing functions.This multifunctional material offers promising potential for next-generation smart flexible electronic systems.展开更多
The demand for high-temperature electromagnetic wave absorption(EWA)materials has significantly increased alongside advancements in aerospace and communication technologies.Although traditional magnetic absorbers,such...The demand for high-temperature electromagnetic wave absorption(EWA)materials has significantly increased alongside advancements in aerospace and communication technologies.Although traditional magnetic absorbers,such as ferrites and metal powders,show excellent magnetic loss performance at room temperature,they have significant limitations in harsh environments due to their high density,low Curie temperature,and susceptibility to oxidation.In contrast,carbon-containing materials have emerged as promising candidates for high-temperature EWA applications,owing to their high melting point,low density,tunable dielectric loss mechanisms,and superior thermal stability.Unlike magnetic materials,carbon-based systems primarily dissipate electromagnetic energy through conductance loss,dipole polarization,and interfacial polarization,thereby avoiding performance degradation at elevated temperatures.However,several critical challenges remain,including insufficient oxidation resistance,mechanical reliability issues,and the need for stable impedance matching.To address these limitations,recent strategies such as defect engineering,heterointerface construction,and metamaterial design have been proposed to enhance thermal stability and functional performance.This review provides a systematic summary of recent advances in carbon-containing absorbers,with a focus on dielectric loss mechanisms,optimization strategies,and multiscale structural design principles.By elucidating the structure–property relationships of carbon materials,carbide ceramics,and novel carbon hybrids,this study aims to offer theoretical and technical guidance for the development of advanced high-temperature electromagnetic wave absorbers,thereby promoting their practical applications in aerospace and telecommunications.展开更多
基金Supported by the National Natural Science Foundation of China(22378181).
文摘The development of materials with excellent microwave absorption(MWA)and electromagnetic interference(EMI)shielding performances has currently received attention.Herein,mesophase pitch-based carbon foam(MPCF)with 3D interconnected pore structure was prepared through the high pressure pyrolysis of mesophase coal tar pitch.It is found that the 3D interconnected cellular pores of MPCF facilitate multiple reflections of electromagnetic waves,which results in the minimum reflection loss(RLmin)value of MPCF reaches-37.84 dB with the effective absorption bandwidth(EAB)of 5.44 GHz at a thickness of 2.70 mm,and the total average electromagnetic shielding effectiveness(SE_(T))under 3.00 mm thickness achieves 26.52 dB in X-band.Subsequently,MPCF is activated by KOH to obtain activated carbon foam(A-MPCF).The average SE_(T)of A-MPCF achieves 103.00 dB for abundant nanopores on the pore cell walls,which leads to a transition from the multiple reflections of electromagnetic waves on the walls to diffuse reflection.Unfortunately,the reflection coefficient(R)of A-MPCF increases from 0.78 to 0.90.To reduce the R value,Fe_(3)O_(4)/A-MPCF was fabricated via the in situ growth of nano Fe_(3)O_(4)on A-MPCF.Consequently,the R value of Fe_(3)O_(4)/A-MPCF was reduced from 0.90 to 0.74,whereas the MWA performance was only slightly decreased.This work proposes a simple strategy for simultaneously adjusting MWA and EMI shielding performances of materials.
文摘The multi-satellite electromagnetic formation flight system is nonlinear and strongly coupled,which makes modeling and optimization challenging.To simplify electromagnetic force evaluation and dynamics modeling,we introduce a reference frame consistent with each satellite body frame,in which the electromagnetic dipoles and electromagnetic forces are represented as two-dimensional vectors.Then,the maneuver time is divided into time intervals,and different satellite sets are activated in each interval,converting the multi-satellite formation reconfiguration problem into an optimal trajectory problem of each two-satellite subsystem.To this end,a token-based dynamic programming method with a switching penalty of active satellite sets is proposed to determine the sequence of satellite sets participating in each time interval,thereby enabling all satellites to reach their desired states.For the two-satellite subsystem with the objectives of minimizing maneuver time and energy consumption,the Gauss pseudo-spectral method is employed to generate the optimal reconfiguration trajectory.Numerical simulations verify the effectiveness of the proposed optimization method.
文摘This study investigates prescribed-time position tracking control for electromagnetic satellite formations subject to model uncertainties and external disturbances.Using the Clohessy-Wiltshire equations as the relative motion dynamics model,a prescribed time output feedback control strategy is proposed.A prescribed-time extended state observer is designed to estimate the relative velocity and external disturbances.The disturbance estimates are then used as the feedforward component of the controller.Building on this framework,a novel prescribed-time active disturbance rejection control strategy for position tracking is developed via a backstepping control design.The convergence of the extended state observer and the stability of the closed-loop system are rigorously analyzed using Lyapunov stability theory.Numerical simulations are performed to validate the effectiveness of the proposed controller.
基金support provided by the Center for Fabrication and Application of Electronic Materials at Dokuz Eylül University,Türkiye。
文摘Biochar and biochar composites are versatile materials that can be used in many applications.In this study,biochar was prepared from sawdust and combined with the yttrium iron garnet(YIG)nanocrystal to investigate the shielding effectiveness of the composite structure.Firstly,the effect of the pyrolysis temperature on the shielding effectiveness of biochar was investigated.Secondly,biochars combined with YIG nanocrystals with different contents and shielding effectiveness of the composites were investigated.The electromagnetic effectiveness of the samples was investigated within the X band(8-12 GHz).The findings indicate that biochar demonstrates enhanced absorption properties with elevated pyrolysis temperatures.Biochars demonstrated an approximate 40 d B shielding effectiveness,while YIG exhibited approximately 7 d B,corresponding to absorption at 8 GHz.However,the combination of biochar and YIG exhibited exceptional absorption,reaching 67.12 d B at 8 GHz.
基金supported by the National Key Research and Development Program of China(2023YFB3907304-3)the National Natural Science Foundation of China(NSFC)(62271050)。
文摘A methodology for the reduction of radar cross section(RCS)of cambered platforms within the target airspace is presented,which utilizes a dual-polarized ultra-wide-angle artificial electromagnetic absorbing surface.By applying the theory of generalized Brewster complex wave impedance matching,five distinct unit cell designs are developed to attain more than95%absorption rate for dual-polarized incident waves within five angular ranges:0°-30°,30°-50°,50°-60°,60°-70°,and 70°-80°.To optimally reduce the RCS of a cambered platform,the five types of units can be evenly distributed on the surface based on the local incident angles of plane waves originating from the target airspace.As an illustrative example,the leading edge of an airfoil is taken into account,and experimental measurements validate the efficiency of the proposed structure.Specifically,the absorbing surface achieves more than 10 dB of RCS reduction in the frequency ranges from 5-10 GHz(about66.7%relative bandwidth)for dual polarizations.
文摘Transient electromagnetic methods are increasingly adopted for field investigation of oil pollution because they provide rapid,non-invasive imaging of subsurface electrical conductivity across depths relevant to vadose-zone impacts,groundwater plumes,and coastal transition zones.This review synthesizes recent advances that have expanded TEM(Transient Electromagnetic Method)’s environmental applicability,including higher dynamic range receivers,multi-moment acquisition that improves shallow-to-deep sensitivity,and diversified deployment platforms spanning ground,mobile/towed,airborne,and coastal/marine configurations,with emerging UAV(Unmanned Aerial Vehicle)options for constrained access.We emphasize the electrical and geochemical basis of hydrocarbon-related signatures,showing why fresh releases may appear resistive through NAPL(Non-Aqueous Phase Liquid)displacement of conductive pore water,whereas aged contamination often produces conductive responses driven by biodegradation,redox evolution,and elevated ionic strength.Because these responses are non-unique and can be confounded by clay-rich lithology,salinity gradients,temperature variability,and cultural infrastructure,contemporary interpretation has shifted toward process-consistent conceptual site models and uncertainty-aware products that communicate depth of investigation and resolution limits.A thematic synthesis of field applications indicates TEM is most reliable for mapping hydrogeological architecture,delineating plausible plume corridors,prioritizing intrusive sampling,and supporting monitoring where repeatability and background variability are controlled.The review concludes that TEM delivers the greatest decision value when integrated in a weight-of-evidence framework with hydrogeology,geochemistry,and targeted ground truth,and it highlights future needs in standardized reporting,robust time-lapse appraisal,and stronger petrophysical links to hydrocarbon transformation.
基金financially supported by the Natural Science Foundation of Shandong Province(No.ZR2024QE446)。
文摘With the rapid development of intelligent electronic and military equipment,multifunctional flexible materials that integrat electromagnetic interference(EMI)shielding,temperature sensing,and information encryption are urgently required.This study presents a bio-inspired hierarchical composite foam fabricated using supercritical nitrogen foaming technology.This material exhibits a honeycomb structure,with pore cell sizes controllable within a range of 30–92μm by regulating the filler.The carbon fiber felt(CFf)provides efficient reflection of electromagnetic waves,while the chloroprene rubber/carbon fiber/carbon black foam facilitates both wave absorption and temperature monitoring through its optimized conductive network.This synergistic mechanism results in an EMI shielding effectiveness(SE)of 60.06 d B with excellent temperature sensing performance(The temperature coefficient of resistance(TCR)is-2.642%/℃)in the 24–70℃ range.Notably,the material has a thermal conductivity of up to 0.159 W/(m·K),and the bio-inspired layered design enables information encryption,demonstrating the material's potential for secure communication applications.The foam also has tensile properties of up to 5.13 MPa and a tear strength of 33.02 N/mm.This biomimetic design overcomes the traditional limitations of flexible materials and provides a transformative solution for next-generation applications such as flexible electronics,aerospace systems and military equipment,which urgently need integrated electromagnetic protection,thermal management and information security.
基金supported by the Fundamental Research Funds for the Central Universities under No.2024KQ130the National Natural Science Foundation of China(No.52373259)。
文摘The advancement of next-generation high-frequency communication systems and stealth detection technologies necessitate the development of efficient,multi-spectrum compatible shielding materials.However,the achievement of simultaneous high efficiency and low reflectivity across microwave,terahertz,and infrared spectra remains a formidable challenge.Herein,a carbonized MXene/polyimide(C-MXene/PI)aerogel material integrating a spatially coupled hierarchically anisotropic structure with stepwise conductivity gradients was constructed.Electromagnetic waves propagate through the top-down vertical disordered horizontal architecture and progressive conductivity gradient of C-MXene/PI aerogel,undergoing stepwise absorption-dissipation-re-dissipation processes.The C-MXene/PI aerogel exhibits an average electromagnetic interference(EMI)shielding effectiveness of91.0 dB in X-band and a reflection coefficient of 0.40.In the terahertz frequency band,the average EMI shielding performance reaches66.2 dB with a reflection coefficient of 0.33.Furthermore,the heterolayered porous architecture of C-MXene/PI aerogels exhibits low thermal conductivity and reduced infrared emissivity,enabling exceptional infrared stealth capability across the 2-16μm wavelength spectrum.This study provides an feasible strategy for constructing low-reflectivity multi-spectrum compatible shielding materials.
基金financially supported by the National Science and Technology Major Project,China(No.2024ZD1002100)the National Natural Science Foundation of China(Nos.42330801,42474112,42504062)+1 种基金the China Postdoctoral Science Foundation(No.2024M761704)Shuimu Tsinghua Scholar Program of Tsinghua University,China(No.2024SM114)。
文摘A three-dimensional(3D)electromagnetic(EM)inversion algorithm based on the nonlinear conjugate gradient(NLCG)method and a two-color plane Gauss-Seidel(GS)multigrid(MG)forward solver is developed to improve inversion efficiency.The results indicate that the computational efficiency of each inversion can be improved by approximately a factor of three by using the proposed MG solver.First,the accuracy of the MG solver is validated through a test on a synthetic model.Next,the numerical performance of the inversion algorithm is evaluated using this model.Finally,the inversion algorithm is applied to a field EM data collected at the Beiya gold polymetallic ore district.A 3D resistivity model is obtained,and the formation process of the metal ore is analyzed.
基金financially supported by the National Natural Science Foundation of China(No.52103127)the Opening Project of the State Key Laboratory of Polymer Materials Engineering(Sichuan University)(No.sklpme2022-4-10)Shaanxi Provincial Science and Technology Department(No.2025GH-YBXM-042).
文摘In this study,an architecture featuring a gradient conductive network structure and three-dimensional dual-continuous network structure is constructed in a carbon nanotubes/cellulose-boron nitride/poly(vinyl alcohol)(CNT/cellulose-BN/PVA)composite.Using cellulose aerogel as a template,CNT were incorporated into the cellulose template by vertically impregnating the CNT suspension.Following the impregnation of BN/PVA and high-pressure compression,three-dimensional dual-continuous network structure was successfully constructed in the CNT/cellulose-BN/PVA composite.The comprehensive performance of the composite,including electromagnetic interference(EMI)shielding and Joule heating performance,was investigated.The results indicate that the total EMI shielding effectiveness(SE)for the CNT/cellulose-BN/PVA composite reveals similar values for electromagnetic waves incident from different directions,but totally different shielding mechanisms.For the CNT/cellulose-BN/PVA composite with three impregnation cycles of CNT,the EMI SE values exceeded 39 dB for electromagnetic waves incident from both the high-and low-CNT-content sides.93%of the microwaves were reflected when electromagnetic waves were incident from the high-CNT-content side,while the reflection coefficient decreased to 0.44 for the transverse direction.In addition,the construction of the dual-continuous network structure enabled the composite to exhibit both excellent electrical conductivity and good thermal conductivity simultaneously,endowing the material with good Joule heating performance.CNT/cellulose-BN/PVA composite films have significant potential for application as EMI shielding materials in extremely cold weather.
基金support from the National Natural Science Foundation of China(No.52174305).
文摘A 3D mathematical model was established to investigate the gas-liquid two-phase flow in Ruhrstahl-Heraeus(RH)vacuum refining process.The flow characteristics of molten steel were calculated using the coupled standard k-εmodel and volume of fluid model.The bubble distribution was tracked by discrete phase model.Electromagnetic field was applied in the up-leg snorkel to enhance the effect of vacuum refining.The effect of swirling flow nozzles combined with electromagnetic stirring(EMS)on the flow characteristics of molten steel and bubble distribution was analyzed.The erosion of the up-leg snorkel was compared.The results show that when the swirling flow nozzles are used,the bubbles exhibit a distinct adherent rising behavior,and the refining efficiency decreases.In addition,the electromagnetic field can significantly improve the refining efficiency,but it brings stronger erosion to the up-leg snorkel.Nevertheless,when using the swirling flow nozzles combined with EMS,the refining performance is further optimized,and the erosion of the up-leg snorkel is also reduced due to its characteristic of bubble distribution.Compared to conventional nozzles,the mixing time was shortened by 16.2%,the recirculation rate increased by 12.5%.and the swirling intensity was strengthened by 8.9%.
基金supported by the National Natural Science Foundation of China(No.52436008)the Inner Mongolia Science and Technology Projects,China(Nos.JMRHZX20210003 and 2023YFCY0009)+3 种基金the Huaneng Group Co Ltd.,China(No.HNKJ23-H50)the National Natural Science Foundation of China(No.22408044)the China Postdoctoral Science Foundation(No.2024M761877)the National Key R&D Program of China(No.SQ2024YFD2200039)。
文摘The electromagnetic wave absorption of silicon carbide nanowires is improved by their uniform and diverse cross-structures.This study introduces a sustainable and high value-added method for synthesizing silicon carbide nanowires using lignite and waste silicon powder as raw materials through carbothermal reduction.The staggered structure of nanowires promotes the creation of interfacial polarization,impedance matching,and multiple loss mechanisms,leading to enhanced electromagnetic absorption performance.The silicon carbide nanowires demonstrate outstanding electromagnetic absorption capabilities with the minimum reflection loss of-48.09 d B at10.08 GHz and an effective absorption bandwidth(the reflection loss less than-10 d B)ranging from 8.54 to 16.68 GHz with a thickness of 2.17 mm.This research presents an innovative approach for utilizing solid waste in an environmentally friendly manner to produce broadband silicon carbide composite absorbers.
基金supported by the National Natural Science Foundation of China(Grant No.52172117,52202105)the Natural Science Basic Research Program of Shaanxi Province(Grant No.2025JC-QYCX-040)。
文摘To address increasing electromagnetic interference and pollution problems,this study proposes a component regulation strategy.Hollow magnetic microspheres derived from metal-organic frameworks(MOFs)were incorporated into carbon fibers(Co@CNFs)through electrospinning technology,forming a sugar-gourd-like heterostructure.This structure promotes the synergy between dielectric and magnetic losses.The full utilization of multi-component synergy and the well-designed heterogeneous interfaces enhances interfacial polarization and optimizes the balance between impedance and high loss.The hollow structure of magnetic microspheres facilitates multiple scattering of electromagnetic waves(EMW).Additionally,the change of heat treatment temperature offers a viable method to adjust the dielectric properties of composites.The results indicate that the Co@CNFs exhibit outstanding EMW attenuation capability,even at an ultralow filler loading of 3 wt%,achieving a reflection loss of-39.7 dB and an effective absorption bandwidth of 7.6 GHz.This study demonstrates the effectiveness of component regulation and offers a viable approach for lightweight,high-performance EMW absorption materials.
基金financially supported by the National Natural Science Foundation of China(52303036)the Natural Science Foundation of Guangxi(2024GXNSFBA010123)+2 种基金the International Science&Technology Innovation Cooperation Project of Sichuan Province(2024YFHZ0232)the International Science&Technology Cooperation Project of Chengdu(2021-GH03-00009-HZ)the Opening Project of State Key Laboratory of Polymer Materials Engineering(Sichuan University)(Sklpme2023-3-18)。
文摘To shield electronics from complicated electromagnetic environments caused by wireless electromagnetic waves,achieving elaborately structural manufacturing while not sacrificing electromagnetic interference shielding performances remains crucial challenges.Herein,we propose a hierarchical manufacturing method that combines the use of 3D printing shear flow field and layer-by-layer assembly for fabricating the structurally customizable and multifunctional polylactic acid@graphene nanoparticle(PLA@GNs)materials.The dynamic behavior of polymer fluids is firstly explored via computational fluid dynamic simulation,and a Weissenberg number is employed to quantitatively analyze the disordered-to-ordered structural evolution of molecular chains and nanoparticles,allowing to tailor the micro-scale ordered structures.Subsequently,the macro-scale 3D architectures of PLA@GNs modules are fabricated by layer-by-layer assembly.Owing to the aligned GNs,the shielding performance reaches 41.2 d B,simultaneously accompanied by a directional thermal conductivity of 3.2 W m^(-1)K^(-1).Moreover,the potential application of 3D-printed shielding modules in specific civilian frequency bands such as 4G(1800–2100 MHz),Bluetooth(2402–2480 MHz),and 5G(3300–3800 MHz)is fully demonstrated.Overall,this work not only establishes a universal methodology about 3D printing shear flow field-driven orientation of two-dimensional nanoparticles within polymer fluids,but also gives a scientific method for advanced manufacturing of the next-generation electromagnetic functional modules for smart electronics.
基金supported by the National Natural Science Foundation of China(Grants No.42130202(CS),42564008(YJ))the National Key Research and Development Program of China(Grant No.2022YFA1604600(CS))+2 种基金supported by the Shenzhen Technology Project(Grant no.JCYJ20241202123905008)Ningxia Natural Science Foundation(No.2024AAC03080)the International Space Science Institute(ISSI)in Bern,through ISSI International Team project#556(Cross-scale energy transfer in space plasmas).
文摘How to transform an electromagnetic field across non-inertial frames of reference is a common challenge encountered in electromagnetic space measurements and analyses.Finding clear and precise ways to evaluate transformation formulas can be difficult.This study presents results of a thorough theoretical investigation that has yielded universal transformation formulas;these transformations are successfully applied to two specific scenarios.We find that,for space plasmas,if the relative velocities of structures are significantly lower than the speed of light,Galilean transformations are suitable.The transformations presented in this paper are applicable,in low speed situations,to electromagnetic fields,electric potentials and magnetic vector potentials,and to charge density and current density,measured in various non-inertial reference frames.Truncation errors associated with these simplified transformations are calculated and shown to be acceptable.These findings have broad implications for space physics measurements and analyses.We address two key issues related to non-inertial frame transformations:first,how to derive a general formula for the rotational electric potential of planets with intrinsic magnetic fields;second,how to verify rigorously the calculation of charge density from MMS(Magnetospheric Multiscale)electrostatic field measurements.We suggest that,due to the validity of the Coulomb gauge,the Poisson equation can be applied in situations of low-speed motion,allowing MMS measurement data to be used to calculate minimal-error charge density.
基金support from the National Natural Science Foundation of China (Nos.52377026 and52301192)Taishan Scholars and Young Experts Program of Shandong Province,China (No.tsqn202103057)+2 种基金Natural Science Foundation of Shandong Province,China (Nos.ZR2024ME046 and ZR2024QE313)Natural Science Basic Research Program of Shaanxi,China (No.2025JC-YBMS-396)Postdoctoral Science Foundation of China (No.2024M761554)
文摘The rapid development of electronic devices and communication technologies has resulted in increasingly severe electromagnetic-wave(EW)pollution.Efficient EW absorption(EWA)materials are essential to mitigate their impact and ensure human safety in modern society.Fe-based EWA materials have garnered significant attention owing to their cost-effectiveness,high saturation magnetization,and superior magnetic loss capabilities.This review begins with an introduction to Fe-based EWA materials,followed by a brief description of their EWA mechanisms.Various pristine Fe-based absorbers,such as carbonyl iron powder,ferrite-based materials,Fe-based alloys,Fe-based high-entropy alloys(HEAs),and Fe-based layered ternary transition-metal borides,have been systematically reviewed.Key strategies to enhance the performance of Fe-based composite absorbers,including doping,in-situ oxidation,porous structuring,and composite construction,are critically discussed.Finally,the review presents a summary and future perspectives in this field,highlighting the synergy between Fe-based and high-entropy materials in advancing next-generation EWA for applications in stealth technology,wear-able electronics,and harsh environments.
基金the financial support by the Ningbo Key Research and Development Program(No.2022Z192)Jiangxi Provincial Major Science and Technology Project(No.20233AAE02007)+1 种基金the Key Research and Development Program of Zhejiang Province(No.2024C01157)the National Natural Science Foundation of China(No.52102370)。
文摘With the increasing requirements of electromagnetic wave(EMW)absorption,developing EMW absorbers with high-efficiency anti-corrosion performance which can be effectively applied in extreme corrosive environments is imperative and constitutes a hot issue in the current research.Herein,based on the composition modulation of ZrO_(2)and SiO_(2)layer,the dual-oxides confined carbonyl iron(CI@ZrO_(2)/SiO_(2))composite displays a minimum reflection loss(RLmin)of-48.58 dB@1.9 mm and an effective absorption bandwidth(EAB)of 7.62 GHz@1.6 mm.Besides,the CI@ZrO_(2)/SiO_(2)displays superior corrosion resistance with corrosion current density(i_(corr))of 8.62×10^(-7)A/cm^(2)and polarization resistance(Rp)of 3.64×10^(5)Ω.This work proposes a strategy to optimize the broadband EMW absorption properties as well as the mass production toward the corrosion resistance applications.
基金supported by ZJNSF LZ25E030006Zhejiang Provincial Key Research and Development Program(2024C01157)+2 种基金NSFC under Grant Nos.52473267 and 52401249the National Key Research and Development Program of China under Grant No.2021YFB3501504Zhejiang University Ningbo“Five in One”Campus Project(K-20213539)。
文摘Three-dimensional(3D)-printedgraphene aerogels hold promise for electromagneticwave absorption(EWA)engineering due to itsultralow density,outstanding electromagnetic dissipationwith the flexibility and precision of manufacturingstrategies.However,their high conductivitycauses severe impedance mismatch,limiting EWAperformance.3D printing requirements also constrainthe dielectric properties of printable grapheneinks,hindering the integration of high-performanceabsorbers with advanced manufacturing.This studyproposes a polyacrylic acid(PAA)gel-mediated3D porous graphene oxide(GO)aerogel multiscaleregulation strategy.Precise gel content control enablesdual-gradient tuning of the rheology(Benefitingdirect ink writing(DIW))and dielectric loss(Enhancing EWA)of GO/PAA composites and reduces aerogel density(6.9 mg cm^(-3)from28.2 mg cm^(-3)).Thermal reduction decomposes PAA into amorphous carbon nanoparticles anchored on reduced graphene oxide(rGO),enhancingimpedance matching and absorption via synergistic 0D/2D interfacial polarization and conductive loss.The optimized rGO/PAA aerogelachieves a minimum reflection loss(RL)of-39.86 dB at 2.5 mm and an effective absorption bandwidth(EAB)of 8.36 GHz(9.64-18 GHz)at3.2 mm.Combining DIW and this aerogel,we design a metamaterial absorber(MA)with dual material(dielectric loss)and structural gradients.This MA exhibits an ultrawide EAB of 14 GHz(4-18 GHz)with a total thickness of 7.8 mm.This work establishes a coupled design paradigmof“composition-structure-performance,”providing an engineerable solution for developing lightweight,broadband EWA materials.
基金financially supported by the NNSF of China(Grant Nos.12074095,12374392,and 52403351)the Joint Guidance Project of the Natural Science Foundation of Heilongjiang Province(LH2023A012)。
文摘The development of multifunctional electromagnetic wave-absorbing materials is essential for next-generation flexible electronics and intelligent protection systems.Herein,a novel three-dimensional porous MXene-based film integrated with metallic nickel nanoparticles(Ni-PMF)is designed and synthesized with the potential to address the urgent need for multifunctional electromagnetic wave-absorbing materials in next-generation intelligent systems.By using polystyrene spheres as sacrificial templates,a hierarchical porous architecture is constructed to prevent MXene nanosheet restacking,extend electromagnetic wave propagation paths,and optimize impedance matching.Simultaneously,uniformly distributed Ni nanoparticles introduce abundant heterogeneous interfaces,enhancing interfacial polarization and magnetic loss,which significantly improve electromagnetic wave attenuation.The Ni-PMF film achieves a minimum reflection loss of–64.7 d B and a broad effective absorption bandwidth of 7.2 GHz,covering the full Ku-band and outperforming most reported MXene thin film absorbers.In addition to superior electromagnetic wave absorption,the film demonstrates excellent electrothermal conversion and flexible strain-sensing capabilities,enabling integrated protection and real-time sensing functions.This multifunctional material offers promising potential for next-generation smart flexible electronic systems.
基金supported by the National Natural Science Foundation of China(52572086 and 52502371)the Natural Science Foundation of Henan(242300421010)+2 种基金Scientific and Technological Innovation Talents in Colleges and Universities in Henan Province(22HASTIT001)the Henan Province Natural Science Foundation Outstanding Youth Fund Project(242300421009)the Henan Province science and technology research project(252102320354and 252102230037)。
文摘The demand for high-temperature electromagnetic wave absorption(EWA)materials has significantly increased alongside advancements in aerospace and communication technologies.Although traditional magnetic absorbers,such as ferrites and metal powders,show excellent magnetic loss performance at room temperature,they have significant limitations in harsh environments due to their high density,low Curie temperature,and susceptibility to oxidation.In contrast,carbon-containing materials have emerged as promising candidates for high-temperature EWA applications,owing to their high melting point,low density,tunable dielectric loss mechanisms,and superior thermal stability.Unlike magnetic materials,carbon-based systems primarily dissipate electromagnetic energy through conductance loss,dipole polarization,and interfacial polarization,thereby avoiding performance degradation at elevated temperatures.However,several critical challenges remain,including insufficient oxidation resistance,mechanical reliability issues,and the need for stable impedance matching.To address these limitations,recent strategies such as defect engineering,heterointerface construction,and metamaterial design have been proposed to enhance thermal stability and functional performance.This review provides a systematic summary of recent advances in carbon-containing absorbers,with a focus on dielectric loss mechanisms,optimization strategies,and multiscale structural design principles.By elucidating the structure–property relationships of carbon materials,carbide ceramics,and novel carbon hybrids,this study aims to offer theoretical and technical guidance for the development of advanced high-temperature electromagnetic wave absorbers,thereby promoting their practical applications in aerospace and telecommunications.
