1 Introduction In deeper study of HTSC, it is found that Y<sub>1</sub>Ba<sub>2</sub>Cu<sub>3</sub>O<sub>7-δ</sub> has an unusualproperty of absorbing hydrogen. The abso...1 Introduction In deeper study of HTSC, it is found that Y<sub>1</sub>Ba<sub>2</sub>Cu<sub>3</sub>O<sub>7-δ</sub> has an unusualproperty of absorbing hydrogen. The absorption process could be described by a gen-eral equation （x/2） H<sub>2</sub> + Y<sub>1</sub>Ba<sub>2</sub>Cu<sub>3</sub>O<sub>7-δ</sub>→H<sub>x</sub>Y<sub>1</sub>Ba<sub>2</sub>Cu<sub>3</sub>O<sub>7-δ</sub>.A structural analysis indicates that absorbed hydrogen is located on the Cu-Osurface and its state change with temperature. As an isotope of hydrogen,deuterium can have simlar effects. Therefore we have experimentally studied展开更多
Electromagnetic(EM)metamaterial absorbers(MMAs)with broadband absorption are of growing interest for applications such as stealth and EM interference mitigation.In this work,we present a novel 3D-printed MMA based on ...Electromagnetic(EM)metamaterial absorbers(MMAs)with broadband absorption are of growing interest for applications such as stealth and EM interference mitigation.In this work,we present a novel 3D-printed MMA based on a fused annular microfluidic metaatom(FAMMA)architecture,designed for W-band absorption.The FAMMA structure features three kinds of orthogonally fused annual meta-atoms,forming a complex 3D microfluidic meta-atom with intricate architecture.Fabricated via high-precision micro 3D printing technology,the FAMMA-based MMA exploits the synergistic solid-liquid coupling effect of the unique three-dimensional orthogonal structure to achieve strong broadband absorption.Three representative FAMMAs with different geometric dimensions have achieved ultra-low reflection loss(RL of-42.1 dB),ultra-broadband effective absorption bandwidth(EAB of 31.3 GHz),and dual-band absorption(in 76.0-85.3 and 99.1-105.6 GHz),respectively.The underlying absorption mechanisms are elucidated by impedance matching theory and electromagnetic field distribution analyses.Application demonstrations show that the FAMMA-based MMA significantly suppresses radar echo power and renders metallic targets undetectable to both radar detector and radar imaging systems,highlighting its potential in stealth technology.Overall,this work establishes a new design concept for high-performance broadband millimeter wave MMAs,opening new avenue for future applications such as high-speed communication,through-wall sensing,and drone detection.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
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
Materials exhibiting broadband nonlinear optical responses are critically important for ultrafast photonics applications,particularly as saturable absorbers(SAs)that facilitate broadband optical pulse generation.In th...Materials exhibiting broadband nonlinear optical responses are critically important for ultrafast photonics applications,particularly as saturable absorbers(SAs)that facilitate broadband optical pulse generation.In this study,tea polyphenolpolyvinyl alcohol(TP-PVA)composite films are synthesized via a polymer embedding method and employed as SAs to initiate ultrafast pulse operation in fiber lasers.The TP-PVA SA film exhibits excellent broadband saturable absorption performance at wavelengths of 1.0μm,1.5μm,and 2.0μm,with modulation depths of 54.21%,41.41%,and 51.16%,respectively.Stable passively mode-locked pulses with pulse widths of 588 fs,419 fs,and 743 fs are generated in Yb-,Er-,and Tm-doped fiber lasers,respectively.This work confirms the effective performance of TP-PVA as a broadband SA,and establishes a foundation for the integration of novel and sustainable materials within ultrafast photonic systems.The approach paves the way for developing compact broadband ultrafast laser systems operating in the near-infrared spectral region.展开更多
Though the formation of polysulfide is desirable,as it contributes to the capacity build-up,it must not leak into the electrolyte.The loss of polysulfide causes capacity fade,a change in the local chemistry of the ele...Though the formation of polysulfide is desirable,as it contributes to the capacity build-up,it must not leak into the electrolyte.The loss of polysulfide causes capacity fade,a change in the local chemistry of the electrolyte,and anode poisoning.Constant efforts are in progress to find suitable polysulfide-absorbing materials;however,the magical polysulfide absorber is yet to be discovered or developed.Experimental methods alone often fall short in accelerating the investigations may be due to the complex Nature of the testing.This review focuses on the importance of computational methods,particularly density functional theory(DFT),in screening suitable polysulfide absorbers.It highlights the critical role of anchoring materials in improving Na-S battery performance,including pristine and doped graphene,metal–organic frameworks,carbon Nanofibers,vanadium disulfide,MXenes,and metal sulfides.By examining adsorption energies,charge transfer mechanisms,and catalytic properties,this review provides insights into the design of advanced materials that can effectively immobilize polysulfides and enhance battery stability.The review aims to guide future research efforts toward the development of high-performance RT Na-S batteries through a comprehensive understanding of the polysulfide-absorbing materials.展开更多
Since the view that the localized rail third-order bending mode can cause high-order polygonization(mainly 18-23)of high-speed train wheels was put forward in 2017,many scholars have attempted to link a connection bet...Since the view that the localized rail third-order bending mode can cause high-order polygonization(mainly 18-23)of high-speed train wheels was put forward in 2017,many scholars have attempted to link a connection between the localized rail bending modes and wheel polygonization phenomenon and polygonal wheel passing frequency.This paper first establishes a flexible track model considering the structural and parametric characteristics of fasteners,verifies the model by using vehicle tracking test data,then investigates the influence of fastener parameter matching on the localized rail bending modes,and obtains the following conclusions:(1)There is nearly a 1:1 mapping relationship between the localized rail bending modal frequency and polygonal wheel passing(PWP)frequency,which supports that the localized rail bending mode is one of the causes of wheel polygonization.(2)The iron plate of the fastener system plays a role of dynamic vibration absorber in the vehicle-rail coupled system,and the fastener parameters significantly influence the localized rail bending modal vibration.Finally,this paper proposes a design principle of a high-frequency vibration-absorbing fastener,which provides a feasible solution to mitigate the localized rail bending modal vibration and high-order wheel polygonization.Meanwhile,it points out that this measure may induce other high-frequency vibration problems,e.g.,aggravating modal vibration above 800 Hz.Further,this paper proposes a concept of differentiated arrangement of fasteners,suggesting that different high-frequency vibration-absorbing fasteners be installed in different sections of the whole line to make the localized rail bending modal frequency of the whole line disordered,thus disrupting and further mitigating the development of the wheel polygonization.展开更多
UV-absorbing additives have recently been demonstrated to be effective interfacial modifiers that simultaneously enhance the UV stability and crystallization of halide perovskite.However,the underlying mechanisms conc...UV-absorbing additives have recently been demonstrated to be effective interfacial modifiers that simultaneously enhance the UV stability and crystallization of halide perovskite.However,the underlying mechanisms concerning UV absorption,defect passivation,and efficacy optimization of these additives remain unresolved.Herein,two UV tautomeric absorbers(UV320 and UV327)are selected as defect-passivators for perovskites.The keto-enol tautomeric evolution processes and corresponding defect passivation performance/mechanism of both the original molecules and their tautomers are thoroughly compared and elucidated through experimental characterizations and density functional theory calculations.The additional carbonyl(-C=O)groups generated through the keto-enol tautomeric process triggered by the Cl atom in UV327 ultimately provide superior chemical coordination and enhanced defect-passivation capability compared to the original counterparts.Moreover,the versatility of K-UV327 is further demonstrated by its optimization of SnO_(2)film quality,interfacial energy band alignment,charge extraction efficiency,and defect state suppression.The photodetector optimized by UV327's tautomer achieves an ultralow dark current density of 3.22×10^(-10)A cm^(-2),an enhanced linear dynamic range of 94.14 d B,and a fast response time of 23.35/26.19μs.Notably,unencapsulated devices maintain a stable response at 3900 Hz following 300 h exposure to 40%±5%relative humidity and 30 h UV irradiation.展开更多
The emergence of precision electronic devices and wearable electronic products urgently requires high-performance multifunctional electromagnetic wave(EMW)absorbers to meet the applicability and versatility in various...The emergence of precision electronic devices and wearable electronic products urgently requires high-performance multifunctional electromagnetic wave(EMW)absorbers to meet the applicability and versatility in various applications.Herein,a dual-network(DN)gel was successfully prepared using acrylamide and sodium lignosulphonate as the basic units by simple chemical cross-linking and physical cross-linking methods.Specifically,the hydrogel forms two types of cross-linking networks through metal coordination and hydrogen bonding.Benefiting from the combined effects of dipole polarization and conductivity loss,the gel achieves an effective absorption bandwidth(EAB)of 6.74 GHz at a thickness of only 1.89 mm,demonstrating excellent EMW absorption performance.In addition,this unique structural configuration endows the EMW absorber with multifunctional features,such as remarkable tensile strength,good environmental compatibility,ultraviolet(UV)resistance,and excellent adhesion.Integrating multiple functional features into the EMW gels displays a broad application prospect in a variety of application scenarios.This research reveals the significance of DN structure design in the electromagnetic wave absorption(EWA)performance of gel-based materials,providing a substantial foundation for the multifunctional design of gel-based absorbers.展开更多
OBJECTIVE:To eliminate ineffective or interfering compounds from the eight absorbed compounds(8ACs),identify the primary ACs that represent the multifunctional therapeutic effects of Zhiqiao(Fructus Aurantii Submaturu...OBJECTIVE:To eliminate ineffective or interfering compounds from the eight absorbed compounds(8ACs),identify the primary ACs that represent the multifunctional therapeutic effects of Zhiqiao(Fructus Aurantii Submaturus)and Houpo(Cortex Magnoliae Officinalis)(FM),along with elucidating their underlying mechanisms.METHODS:Key multifunctional ACs were screened through ex vivo-to-in vitro extrapolation(ex vivo dose=serum concentration)and validated in vivo,with efficacy assessed via contribution(dose=FM content).Functional magnetic resonance imaging analyzed brain regions's blood oxygen level-dependent(BOLD)changes,and the molecular mechanisms were analyzed by transcriptome of the dentate gyrus(DG).RESULTS:The results showed that representative 2ACs(Nobiletin+Magnolol)and 3ACs(Nobiletin+Magnolol+Meranzin hydrate)screened on ex vivo experiment by the criteria of contribution ranking contributed 80.72%-126.74%of the antidepressant and prokinetic effects of the FM(improvement of depressive-like behaviours,gastrointestinal disorder,monoamine neurotransmitters,ghrelin,endocrine hormones,pro-inflammatory factors,oxidative stress indicators).In addition,3ACs demonstrated superiority over 2ACs in improving depression and levels of multiple stress mediators.Zhiqiao(Fructus Aurantii Submaturus)(FRA)reduced acute stress-induced hyperactivation of the cingulate cortex,thalamus,hypothalamus,and entorhinal cortex and elevated BOLD signaling in the insular cortex,temporal association cortex.Furthermore,FRA upregulated pathways of neurotransmitter receptor activity and serotonergic synaptic function and downregulated inflammation-related pathways at the genetic level.CONCLUSION:2ACs and 3ACs closely reflected FM's multifunctional effect in antidepressant and prokinetic.FRA restores stress-impaired neural connectivity in functional brain regions and improves synaptic plasticity and neurogenesis at the genetic level.展开更多
We discuss recent progress in using machine-learning(ML)-enabled inverse design techniques applied to photonic devices and components.Specifically,we highlight the design of optical sources,including fiber and semicon...We discuss recent progress in using machine-learning(ML)-enabled inverse design techniques applied to photonic devices and components.Specifically,we highlight the design of optical sources,including fiber and semiconductor lasers,as well as Raman and semiconductor optical amplifiers.Although inverse design approaches for optical detectors remain relatively underexplored,we examine optical layers,particularly metamaterial absorbers,as promising candidates for high-performance optical detection.In addition,we underscore advancements in inverse designing passive optical components,including beam splitters,gratings,and optical fibers.These optical blocks are fundamental in developing next-generation standalone optical communication systems and optical sensing networks,including integrated sensing and communication technologies.While categorizing various reported deep learning architectures across five paradigms,we offer a paradigm-based perspective that reveals how different ML techniques function within modern inverse design methods and enable fast,data-driven solutions that significantly reduce design time and computational demands compared with traditional optimization methods.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
The rapid development of modern 5G technology has significantly increased the demand for multifunctional electromagnetic interference(EMI)shielding and wave-absorbing materials.Hence,a densification strategy was propo...The rapid development of modern 5G technology has significantly increased the demand for multifunctional electromagnetic interference(EMI)shielding and wave-absorbing materials.Hence,a densification strategy was proposed to fabricate multifunctional rigid polyimide(PI)composite foam.As a result,the composite PI foam exhibits excellent mechanical properties,with tensile and bending strengths of 4.7 and 21.1 MPa,respectively.Moreover,the composite PI foam achieves a promising EMI shielding performance with a high absorption coefficient(A)of 0.71,coupled with an X-band(8.2–12.4 GHz)EMI rating of 44 dB(2 mm)due to its high conductivity(20.29 ms/mm).Satisfyingly,the composite PI foam also has an optimal reflection loss(RL)of up to−46.4 dB and an effective absorption bandwidth(EAB)(RL<−10 dB)that covers the entire X-band.Meanwhile,the fabricated foam demonstrates a Joule heating performance of 89.2°C under supply voltages(3–9 V)and rapid response time(within 20 s)for stable and reproducible performance in long-term cycling.This work provides a versatile strategy for the development of lightweight and high-strength materials for EMI shielding and microwave absorption,demonstrating great potential for aerospace,microelectronics,and energy conversion applications.展开更多
Coating uniform,compact and thin nanoshells on micro-sized particles is critical to various applications including anticorrosive broadband microwave absorbing materials(MAMs),yet effective processing methods remain la...Coating uniform,compact and thin nanoshells on micro-sized particles is critical to various applications including anticorrosive broadband microwave absorbing materials(MAMs),yet effective processing methods remain lacking.In this work,a turbulent sol-gel method is developed to coat the desired SiO2 nanoshells on flaky carbonyl iron(FCI)particles.The adding millimeter-sized zirconia balls,driven by the orbital shaking,squeeze the solution and create significant relative motion between the liquid and balls,which generates turbulent flows.This significantly promotes the heterogeneous nucleation rate and high nucleation density,ultimately forming highly compact and uniform SiO2 nanoshells covering FCI particles to enhance the electromagnetic absorption and anticorrosion properties.The as-obtained core-shell particles minimize the interface polarization and retain high magnetic loss,resulting in an improved impedance matching and a reflection loss<−10 dB with a bandwidth of 6.5 GHz at a thin thickness of 1 mm.Moreover,they also show a substantial order-of-magnitude improvement in anticorrosion performance.This work provides a promising method to fabricate anticorrosive,broadband and thin-thickness MAMs.The turbulent sol-gel method developed herein offers a facile and effective approach for fabricating uniform compact nanoshells on micro-sized particles.展开更多
In this paper, we have demonstrated an Er-doped ultrafast laser with a single mode fiber-gradient index multimode fiber-single mode fiber(SMF-GIMF-SMF, SMS) structure as saturable absorber(SA), which can generate not ...In this paper, we have demonstrated an Er-doped ultrafast laser with a single mode fiber-gradient index multimode fiber-single mode fiber(SMF-GIMF-SMF, SMS) structure as saturable absorber(SA), which can generate not only stable single-pulse state, but also special mode-locked pulses with the characteristics of high energy and noisy behaviors at proper pump power and cavity polarization state. In addition, we have deeply investigated the real-time spectral evolutions of the mode-locked pulses through the dispersive Fourier transformation(DFT) technique. It can be found that the pulse regime can actually consist of a lot of small noise pulses with randomly varying intensities. We believe that these results will further enrich the nonlinear dynamical processes in the ultrafast lasers.展开更多
Gels and conductive polymer composites,including hydrogen bonds(HBs),have emerged as promising materials for electro-magnetic wave(EMW)absorption across various applications.However,the relationship between conduction...Gels and conductive polymer composites,including hydrogen bonds(HBs),have emerged as promising materials for electro-magnetic wave(EMW)absorption across various applications.However,the relationship between conduction loss in EMW-absorbing materials and charge transfer in HB remains to be fully understood.In this study,we developed a series of deep eutectic gels to fine-tune the quantity of HB by adjusting the molar ratio of choline chloride(ChCl)and ethylene glycol(EG).Owing to the unique properties of deep eutectic gels,the effects of magnetic loss and polarization loss on EMW attenuation can be disregarded.Our results indicate that the quantity of HB initially increases and then decreases with the introduction of EG,with HB-induced conductive loss following similar pat-terns.At a ChCl and EG molar ratio of 2.4,the gel labeled G22-CE2.4 exhibited the best EMW absorption performance,characterized by an effective absorption bandwidth of 8.50 GHz and a thickness of 2.54 mm.This superior performance is attributed to the synergistic ef-fects of excellent conductive loss and impedance matching generated by the optimal number of HB.This work elucidates the role of HB in dielectric loss for the first time and provides valuable insights into the optimal design of supramolecular polymer absorbers.展开更多
With the booming development of electronic information science and 5G communication technology,electromagnetic radi-ation pollution poses a huge threat and damage to humanity.Developing novel and high-performance elec...With the booming development of electronic information science and 5G communication technology,electromagnetic radi-ation pollution poses a huge threat and damage to humanity.Developing novel and high-performance electromagnetic wave(EMW)ab-sorbers is an effective method to solve the above issue and has attracted the attention of many researchers.As a typical magnetic material,ferrite plays an important role in the design of high-performance EMW absorbers,and related research focuses on diversified synthesis methods,strong absorption performance,and refined microstructure development.Herein,we focus on the synthesis of ferrites and their composites and introduce recent advances in the high-temperature solid-phase method,sol-gel method,chemical coprecipitation method,and solvent thermal method in the preparation of high-performance EMW absorbers.This review aims to help researchers understand the advantages and disadvantages of ferrite-based EMW absorbers fabricated through these methods.It also provides important guidance and reference for researchers to design high-performance EMW absorption materials based on ferrite.展开更多
Cu_(2)ZnSn(S,Se)_(4)(CZTSSe)is considered to be the most potential light-absorbing material to replace CuInGaSe_(2)(CIGS),but the actual photoelectric conversion efficiency of such cells is much lower than that of CIG...Cu_(2)ZnSn(S,Se)_(4)(CZTSSe)is considered to be the most potential light-absorbing material to replace CuInGaSe_(2)(CIGS),but the actual photoelectric conversion efficiency of such cells is much lower than that of CIGS.One of the reasons is the high recombination rate of carriers at the interface.In this paper,in order to reduce the carrier recombination,a new solar cell structure with double absorber layers of Al-doped ZnO(AZO)/intrinsic(i)-ZnO/CdS/CZTS_(x1)Se_(1−x1)(CZTSSe_(1))/CZTS_(x2)Se_(1−x2)(CZTSSe_(2))/Mo was proposed,and the optimal conduction band offsets(CBOs)of CdS/CZTSSe_(1) interface and CZTSSe_(1)/CZTSSe_(2) interface were determined by changing the S ratio in CZTSSe_(1) and CZTSSe_(2),and the effect of thickness of CZTSSe_(1) on the performance of the cell was studied.The efficiencies of the optimized single and double absorber layers reached 17.97%and 23.4%,respectively.Compared with the single absorber layer structure,the proposed structure with double absorber layers has better cell performance.展开更多
Carbon-based foams with a three-dimensional structure can serve as a lightweight template for the rational design and control-lable preparation of metal oxide/carbon-based composite microwave absorption materials.In t...Carbon-based foams with a three-dimensional structure can serve as a lightweight template for the rational design and control-lable preparation of metal oxide/carbon-based composite microwave absorption materials.In this study,a flake-like nickel cobaltate/re-duced graphene oxide/melamine-derived carbon foam(FNC/RGO/MDCF)was successfully fabricated through a combination of solvo-thermal treatment and high-temperature pyrolysis.Results indicated that RGO was evenly distributed in the MDCF skeleton,providing ef-fective support for the load growth of FNC on its surface.Sample S3,the FNC/RGO/MDCF composite prepared by solvothermal method for 16 h,exhibited a minimum reflection loss(RL_(min))of-66.44 dB at a thickness of 2.29 mm.When the thickness was reduced to 1.50 mm,the optimal effective absorption bandwidth was 3.84 GHz.Analysis of the absorption mechanism of FNC/RGO/MDCF revealed that its excellent absorption performance was primarily attributed to the combined effects of conduction loss,multiple reflection,scattering,in-terface polarization,and dipole polarization.展开更多
The increase in the utilization of infrared heat detection technology in military applications necessitates research on composites with improved thermal transmission performance and microwave absorption capabilities.T...The increase in the utilization of infrared heat detection technology in military applications necessitates research on composites with improved thermal transmission performance and microwave absorption capabilities.This study satisfactorily fabricated a series of MoS_(2)/BN-xyz composites(which were characterized by the weight ratio of MoS_(2)to BN,denoted by xy:z)through chemical vapor depos-ition,which resulted in their improved thermal stability and thermal transmission performance.The results show that the remaining mass of MoS_(2)/BN-101 was as high as 69.25wt%at 800℃under air atmosphere,and a temperature difference of 31.7℃was maintained between the surface temperature and the heating source at a heating temperature of 200℃.Furthermore,MoS_(2)/BN-301 exhibited an im-pressive minimum reflection loss value of-32.21 dB at 4.0 mm and a wide effective attenuation bandwidth ranging from 9.32 to 18.00 GHz(8.68 GHz).Therefore,these simplified synthesized MoS_(2)/BN-xyz composites demonstrate great potential as highly efficient con-tenders for the enhancement of microwave absorption performance and thermal conductance.展开更多
文摘1 Introduction In deeper study of HTSC, it is found that Y<sub>1</sub>Ba<sub>2</sub>Cu<sub>3</sub>O<sub>7-δ</sub> has an unusualproperty of absorbing hydrogen. The absorption process could be described by a gen-eral equation （x/2） H<sub>2</sub> + Y<sub>1</sub>Ba<sub>2</sub>Cu<sub>3</sub>O<sub>7-δ</sub>→H<sub>x</sub>Y<sub>1</sub>Ba<sub>2</sub>Cu<sub>3</sub>O<sub>7-δ</sub>.A structural analysis indicates that absorbed hydrogen is located on the Cu-Osurface and its state change with temperature. As an isotope of hydrogen,deuterium can have simlar effects. Therefore we have experimentally studied
基金support by the National Key Research and Development Program of China(Xiaosheng Zhang:No.2022YFB3206100)the National Natural Science Foundation of China(Yi Zhang:No.62271107,Qiye Wen:No.62235004,62311530115,Shaomeng Wang:T2241002)+2 种基金the Natural Science Foundation of Sichuan Province(Yi Zhang:No.2025ZNSFSC0464)the Key R&D Program of Mianyang(Xiaosheng Zhang:No.2023ZYDF019)the Fundamental Research Funds for the Central Universities(Yi Zhang:No.ZYGX2022YGRH007).
文摘Electromagnetic(EM)metamaterial absorbers(MMAs)with broadband absorption are of growing interest for applications such as stealth and EM interference mitigation.In this work,we present a novel 3D-printed MMA based on a fused annular microfluidic metaatom(FAMMA)architecture,designed for W-band absorption.The FAMMA structure features three kinds of orthogonally fused annual meta-atoms,forming a complex 3D microfluidic meta-atom with intricate architecture.Fabricated via high-precision micro 3D printing technology,the FAMMA-based MMA exploits the synergistic solid-liquid coupling effect of the unique three-dimensional orthogonal structure to achieve strong broadband absorption.Three representative FAMMAs with different geometric dimensions have achieved ultra-low reflection loss(RL of-42.1 dB),ultra-broadband effective absorption bandwidth(EAB of 31.3 GHz),and dual-band absorption(in 76.0-85.3 and 99.1-105.6 GHz),respectively.The underlying absorption mechanisms are elucidated by impedance matching theory and electromagnetic field distribution analyses.Application demonstrations show that the FAMMA-based MMA significantly suppresses radar echo power and renders metallic targets undetectable to both radar detector and radar imaging systems,highlighting its potential in stealth technology.Overall,this work establishes a new design concept for high-performance broadband millimeter wave MMAs,opening new avenue for future applications such as high-speed communication,through-wall sensing,and drone detection.
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.
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supported by the Opening Foundation of Hubei Key Laboratory for New Textile Materials and Applications Research(Grant No.FZXCL202410)the Key Project of Science and Technology Research Program of Hubei Provincial Department of Education,China(Grant No.D20231704)+1 种基金Wuhan Textile University(Grant No.523058)the Foundation of Wuhan Textile University(Grant No.K24058)。
文摘Materials exhibiting broadband nonlinear optical responses are critically important for ultrafast photonics applications,particularly as saturable absorbers(SAs)that facilitate broadband optical pulse generation.In this study,tea polyphenolpolyvinyl alcohol(TP-PVA)composite films are synthesized via a polymer embedding method and employed as SAs to initiate ultrafast pulse operation in fiber lasers.The TP-PVA SA film exhibits excellent broadband saturable absorption performance at wavelengths of 1.0μm,1.5μm,and 2.0μm,with modulation depths of 54.21%,41.41%,and 51.16%,respectively.Stable passively mode-locked pulses with pulse widths of 588 fs,419 fs,and 743 fs are generated in Yb-,Er-,and Tm-doped fiber lasers,respectively.This work confirms the effective performance of TP-PVA as a broadband SA,and establishes a foundation for the integration of novel and sustainable materials within ultrafast photonic systems.The approach paves the way for developing compact broadband ultrafast laser systems operating in the near-infrared spectral region.
基金supported by the Indian Institute of Technology Delhi (IIT Delhi)
文摘Though the formation of polysulfide is desirable,as it contributes to the capacity build-up,it must not leak into the electrolyte.The loss of polysulfide causes capacity fade,a change in the local chemistry of the electrolyte,and anode poisoning.Constant efforts are in progress to find suitable polysulfide-absorbing materials;however,the magical polysulfide absorber is yet to be discovered or developed.Experimental methods alone often fall short in accelerating the investigations may be due to the complex Nature of the testing.This review focuses on the importance of computational methods,particularly density functional theory(DFT),in screening suitable polysulfide absorbers.It highlights the critical role of anchoring materials in improving Na-S battery performance,including pristine and doped graphene,metal–organic frameworks,carbon Nanofibers,vanadium disulfide,MXenes,and metal sulfides.By examining adsorption energies,charge transfer mechanisms,and catalytic properties,this review provides insights into the design of advanced materials that can effectively immobilize polysulfides and enhance battery stability.The review aims to guide future research efforts toward the development of high-performance RT Na-S batteries through a comprehensive understanding of the polysulfide-absorbing materials.
基金supported by the National Natural Science Foundation of China(Grant Nos.:52202423,U2268211,and 52475136)the China Postdoctoral Science Foundation(Grant Nos.:2022M712636 and 2023T160546)+1 种基金the Natural Science Foundation of Sichuan Province(Grant No.:2025ZNSFSC0398)the Independent R&D Project of the State Key Laboratory of Traction Power(Grant No.:2023TPL-T14).
文摘Since the view that the localized rail third-order bending mode can cause high-order polygonization(mainly 18-23)of high-speed train wheels was put forward in 2017,many scholars have attempted to link a connection between the localized rail bending modes and wheel polygonization phenomenon and polygonal wheel passing frequency.This paper first establishes a flexible track model considering the structural and parametric characteristics of fasteners,verifies the model by using vehicle tracking test data,then investigates the influence of fastener parameter matching on the localized rail bending modes,and obtains the following conclusions:(1)There is nearly a 1:1 mapping relationship between the localized rail bending modal frequency and polygonal wheel passing(PWP)frequency,which supports that the localized rail bending mode is one of the causes of wheel polygonization.(2)The iron plate of the fastener system plays a role of dynamic vibration absorber in the vehicle-rail coupled system,and the fastener parameters significantly influence the localized rail bending modal vibration.Finally,this paper proposes a design principle of a high-frequency vibration-absorbing fastener,which provides a feasible solution to mitigate the localized rail bending modal vibration and high-order wheel polygonization.Meanwhile,it points out that this measure may induce other high-frequency vibration problems,e.g.,aggravating modal vibration above 800 Hz.Further,this paper proposes a concept of differentiated arrangement of fasteners,suggesting that different high-frequency vibration-absorbing fasteners be installed in different sections of the whole line to make the localized rail bending modal frequency of the whole line disordered,thus disrupting and further mitigating the development of the wheel polygonization.
基金the financial support from Xingdian Creative Industry Talent Project of Yunnan Province(No.XDYC-CYCX-2024-0025)Science and Technology Special Projects of Southwest United Graduate School and Innovative Team of Yunnan Province。
文摘UV-absorbing additives have recently been demonstrated to be effective interfacial modifiers that simultaneously enhance the UV stability and crystallization of halide perovskite.However,the underlying mechanisms concerning UV absorption,defect passivation,and efficacy optimization of these additives remain unresolved.Herein,two UV tautomeric absorbers(UV320 and UV327)are selected as defect-passivators for perovskites.The keto-enol tautomeric evolution processes and corresponding defect passivation performance/mechanism of both the original molecules and their tautomers are thoroughly compared and elucidated through experimental characterizations and density functional theory calculations.The additional carbonyl(-C=O)groups generated through the keto-enol tautomeric process triggered by the Cl atom in UV327 ultimately provide superior chemical coordination and enhanced defect-passivation capability compared to the original counterparts.Moreover,the versatility of K-UV327 is further demonstrated by its optimization of SnO_(2)film quality,interfacial energy band alignment,charge extraction efficiency,and defect state suppression.The photodetector optimized by UV327's tautomer achieves an ultralow dark current density of 3.22×10^(-10)A cm^(-2),an enhanced linear dynamic range of 94.14 d B,and a fast response time of 23.35/26.19μs.Notably,unencapsulated devices maintain a stable response at 3900 Hz following 300 h exposure to 40%±5%relative humidity and 30 h UV irradiation.
基金supported by the National Natural Science Foundation of China(Nos.52231007,51872238,52074227,and 21806129)the Fundamental Research Funds for the Central Universities(Nos.3102018zy045,3102019AX11,and 5000220455)the Natural Science Basic Research Plan in Shaanxi Province of China(Nos.2017JQ5116 and 2020JM-118).
文摘The emergence of precision electronic devices and wearable electronic products urgently requires high-performance multifunctional electromagnetic wave(EMW)absorbers to meet the applicability and versatility in various applications.Herein,a dual-network(DN)gel was successfully prepared using acrylamide and sodium lignosulphonate as the basic units by simple chemical cross-linking and physical cross-linking methods.Specifically,the hydrogel forms two types of cross-linking networks through metal coordination and hydrogen bonding.Benefiting from the combined effects of dipole polarization and conductivity loss,the gel achieves an effective absorption bandwidth(EAB)of 6.74 GHz at a thickness of only 1.89 mm,demonstrating excellent EMW absorption performance.In addition,this unique structural configuration endows the EMW absorber with multifunctional features,such as remarkable tensile strength,good environmental compatibility,ultraviolet(UV)resistance,and excellent adhesion.Integrating multiple functional features into the EMW gels displays a broad application prospect in a variety of application scenarios.This research reveals the significance of DN structure design in the electromagnetic wave absorption(EWA)performance of gel-based materials,providing a substantial foundation for the multifunctional design of gel-based absorbers.
基金Supported by the Jiangsu Province’s Colleges and Universities(Integration of Chinese and Western Medicine)the National Natural Science Foundation of China[Methanism on Molecular and Hippocampus-Thalamus Neurocircuitry of Rapid Prokinetic and Antidepressant by Shugan Following Acute Stress(81973589)]The Relationship Between Stress,Ghrelin Signaling,Liver-Soothing and Antidepressant Prokinetic Mechanisms(81573797)。
文摘OBJECTIVE:To eliminate ineffective or interfering compounds from the eight absorbed compounds(8ACs),identify the primary ACs that represent the multifunctional therapeutic effects of Zhiqiao(Fructus Aurantii Submaturus)and Houpo(Cortex Magnoliae Officinalis)(FM),along with elucidating their underlying mechanisms.METHODS:Key multifunctional ACs were screened through ex vivo-to-in vitro extrapolation(ex vivo dose=serum concentration)and validated in vivo,with efficacy assessed via contribution(dose=FM content).Functional magnetic resonance imaging analyzed brain regions's blood oxygen level-dependent(BOLD)changes,and the molecular mechanisms were analyzed by transcriptome of the dentate gyrus(DG).RESULTS:The results showed that representative 2ACs(Nobiletin+Magnolol)and 3ACs(Nobiletin+Magnolol+Meranzin hydrate)screened on ex vivo experiment by the criteria of contribution ranking contributed 80.72%-126.74%of the antidepressant and prokinetic effects of the FM(improvement of depressive-like behaviours,gastrointestinal disorder,monoamine neurotransmitters,ghrelin,endocrine hormones,pro-inflammatory factors,oxidative stress indicators).In addition,3ACs demonstrated superiority over 2ACs in improving depression and levels of multiple stress mediators.Zhiqiao(Fructus Aurantii Submaturus)(FRA)reduced acute stress-induced hyperactivation of the cingulate cortex,thalamus,hypothalamus,and entorhinal cortex and elevated BOLD signaling in the insular cortex,temporal association cortex.Furthermore,FRA upregulated pathways of neurotransmitter receptor activity and serotonergic synaptic function and downregulated inflammation-related pathways at the genetic level.CONCLUSION:2ACs and 3ACs closely reflected FM's multifunctional effect in antidepressant and prokinetic.FRA restores stress-impaired neural connectivity in functional brain regions and improves synaptic plasticity and neurogenesis at the genetic level.
基金the School of Engineering and Built Environment at Anglia Ruskin University,UK,for the supportthe support of IRC-CSS and the Electrical Engineering Department,KFUPM,Saudi Arabia。
文摘We discuss recent progress in using machine-learning(ML)-enabled inverse design techniques applied to photonic devices and components.Specifically,we highlight the design of optical sources,including fiber and semiconductor lasers,as well as Raman and semiconductor optical amplifiers.Although inverse design approaches for optical detectors remain relatively underexplored,we examine optical layers,particularly metamaterial absorbers,as promising candidates for high-performance optical detection.In addition,we underscore advancements in inverse designing passive optical components,including beam splitters,gratings,and optical fibers.These optical blocks are fundamental in developing next-generation standalone optical communication systems and optical sensing networks,including integrated sensing and communication technologies.While categorizing various reported deep learning architectures across five paradigms,we offer a paradigm-based perspective that reveals how different ML techniques function within modern inverse design methods and enable fast,data-driven solutions that significantly reduce design time and computational demands compared with traditional optimization methods.
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support from the Postgraduate Innovation Foundation of Xi'an Polytechnic University(No.chx2024034)the Natural Science Foundation of Shaanxi Province(No.2022JQ-362,2021JQ-677)the Scientific Research Program Funded by Shaanxi Provincial Education Department(No.21JK20180911).
文摘The rapid development of modern 5G technology has significantly increased the demand for multifunctional electromagnetic interference(EMI)shielding and wave-absorbing materials.Hence,a densification strategy was proposed to fabricate multifunctional rigid polyimide(PI)composite foam.As a result,the composite PI foam exhibits excellent mechanical properties,with tensile and bending strengths of 4.7 and 21.1 MPa,respectively.Moreover,the composite PI foam achieves a promising EMI shielding performance with a high absorption coefficient(A)of 0.71,coupled with an X-band(8.2–12.4 GHz)EMI rating of 44 dB(2 mm)due to its high conductivity(20.29 ms/mm).Satisfyingly,the composite PI foam also has an optimal reflection loss(RL)of up to−46.4 dB and an effective absorption bandwidth(EAB)(RL<−10 dB)that covers the entire X-band.Meanwhile,the fabricated foam demonstrates a Joule heating performance of 89.2°C under supply voltages(3–9 V)and rapid response time(within 20 s)for stable and reproducible performance in long-term cycling.This work provides a versatile strategy for the development of lightweight and high-strength materials for EMI shielding and microwave absorption,demonstrating great potential for aerospace,microelectronics,and energy conversion applications.
基金supported by the Innovation Team in Key Areas of the Innovation Talent Promotion Plan(2021)of MOST,Chinathe National Natural Science Foundation of China(Nos.52473078,52071239,52311530074)the Cultivation Program of Wuhan Institute of Photochemistry and Technology(No.GHY2023KF004).
文摘Coating uniform,compact and thin nanoshells on micro-sized particles is critical to various applications including anticorrosive broadband microwave absorbing materials(MAMs),yet effective processing methods remain lacking.In this work,a turbulent sol-gel method is developed to coat the desired SiO2 nanoshells on flaky carbonyl iron(FCI)particles.The adding millimeter-sized zirconia balls,driven by the orbital shaking,squeeze the solution and create significant relative motion between the liquid and balls,which generates turbulent flows.This significantly promotes the heterogeneous nucleation rate and high nucleation density,ultimately forming highly compact and uniform SiO2 nanoshells covering FCI particles to enhance the electromagnetic absorption and anticorrosion properties.The as-obtained core-shell particles minimize the interface polarization and retain high magnetic loss,resulting in an improved impedance matching and a reflection loss<−10 dB with a bandwidth of 6.5 GHz at a thin thickness of 1 mm.Moreover,they also show a substantial order-of-magnitude improvement in anticorrosion performance.This work provides a promising method to fabricate anticorrosive,broadband and thin-thickness MAMs.The turbulent sol-gel method developed herein offers a facile and effective approach for fabricating uniform compact nanoshells on micro-sized particles.
基金supported by the Guangdong Basic and Applied Basic Research Foundation (No.2023A1515010093)the Shenzhen Fundamental Research Program (Stable Support Plan Program)(Nos.JCYJ20220809170611004, 20231121110828001 and 20231121113641002)the National Taipei University of Technology-Shenzhen University Joint Research Program (No.2024001)。
文摘In this paper, we have demonstrated an Er-doped ultrafast laser with a single mode fiber-gradient index multimode fiber-single mode fiber(SMF-GIMF-SMF, SMS) structure as saturable absorber(SA), which can generate not only stable single-pulse state, but also special mode-locked pulses with the characteristics of high energy and noisy behaviors at proper pump power and cavity polarization state. In addition, we have deeply investigated the real-time spectral evolutions of the mode-locked pulses through the dispersive Fourier transformation(DFT) technique. It can be found that the pulse regime can actually consist of a lot of small noise pulses with randomly varying intensities. We believe that these results will further enrich the nonlinear dynamical processes in the ultrafast lasers.
基金supported by the National Nat-ural Science Foundation of China(Nos.51872238,52074227,and 21806129)the Fundamental Research Funds for the Central Universities,China(Nos.3102018zy045 and 3102019AX11)+2 种基金the Guangdong Basic and Applied Basic Research Foundation,China(No.2024A1515010298)the Natural Science Basic Research Plan in Shaanxi Province of China(Nos.2017JQ5116 and 2020JM-118)the Key Laboratory of Icing and Anti/De-icing of CARDC(No.IADL20220401).
文摘Gels and conductive polymer composites,including hydrogen bonds(HBs),have emerged as promising materials for electro-magnetic wave(EMW)absorption across various applications.However,the relationship between conduction loss in EMW-absorbing materials and charge transfer in HB remains to be fully understood.In this study,we developed a series of deep eutectic gels to fine-tune the quantity of HB by adjusting the molar ratio of choline chloride(ChCl)and ethylene glycol(EG).Owing to the unique properties of deep eutectic gels,the effects of magnetic loss and polarization loss on EMW attenuation can be disregarded.Our results indicate that the quantity of HB initially increases and then decreases with the introduction of EG,with HB-induced conductive loss following similar pat-terns.At a ChCl and EG molar ratio of 2.4,the gel labeled G22-CE2.4 exhibited the best EMW absorption performance,characterized by an effective absorption bandwidth of 8.50 GHz and a thickness of 2.54 mm.This superior performance is attributed to the synergistic ef-fects of excellent conductive loss and impedance matching generated by the optimal number of HB.This work elucidates the role of HB in dielectric loss for the first time and provides valuable insights into the optimal design of supramolecular polymer absorbers.
基金supported by the National Natural Science Foundation of China(No.52377026)Taishan Scholars and Young Experts Program of Shandong Province,China(No.tsqn202103057)the Natural Science Foundation of Shandong Province,China(No.ZR2024ME046).
文摘With the booming development of electronic information science and 5G communication technology,electromagnetic radi-ation pollution poses a huge threat and damage to humanity.Developing novel and high-performance electromagnetic wave(EMW)ab-sorbers is an effective method to solve the above issue and has attracted the attention of many researchers.As a typical magnetic material,ferrite plays an important role in the design of high-performance EMW absorbers,and related research focuses on diversified synthesis methods,strong absorption performance,and refined microstructure development.Herein,we focus on the synthesis of ferrites and their composites and introduce recent advances in the high-temperature solid-phase method,sol-gel method,chemical coprecipitation method,and solvent thermal method in the preparation of high-performance EMW absorbers.This review aims to help researchers understand the advantages and disadvantages of ferrite-based EMW absorbers fabricated through these methods.It also provides important guidance and reference for researchers to design high-performance EMW absorption materials based on ferrite.
基金supported by the Science and Technology Innovation Development Program(No.70304901).
文摘Cu_(2)ZnSn(S,Se)_(4)(CZTSSe)is considered to be the most potential light-absorbing material to replace CuInGaSe_(2)(CIGS),but the actual photoelectric conversion efficiency of such cells is much lower than that of CIGS.One of the reasons is the high recombination rate of carriers at the interface.In this paper,in order to reduce the carrier recombination,a new solar cell structure with double absorber layers of Al-doped ZnO(AZO)/intrinsic(i)-ZnO/CdS/CZTS_(x1)Se_(1−x1)(CZTSSe_(1))/CZTS_(x2)Se_(1−x2)(CZTSSe_(2))/Mo was proposed,and the optimal conduction band offsets(CBOs)of CdS/CZTSSe_(1) interface and CZTSSe_(1)/CZTSSe_(2) interface were determined by changing the S ratio in CZTSSe_(1) and CZTSSe_(2),and the effect of thickness of CZTSSe_(1) on the performance of the cell was studied.The efficiencies of the optimized single and double absorber layers reached 17.97%and 23.4%,respectively.Compared with the single absorber layer structure,the proposed structure with double absorber layers has better cell performance.
基金support of the Key Science Research Project in Colleges and Universities of Anhui Province,China(No.2022AH050813)the Medical Special Cultivation Project of Anhui University of Science and Technology,China(No.YZ2023H2A002).
文摘Carbon-based foams with a three-dimensional structure can serve as a lightweight template for the rational design and control-lable preparation of metal oxide/carbon-based composite microwave absorption materials.In this study,a flake-like nickel cobaltate/re-duced graphene oxide/melamine-derived carbon foam(FNC/RGO/MDCF)was successfully fabricated through a combination of solvo-thermal treatment and high-temperature pyrolysis.Results indicated that RGO was evenly distributed in the MDCF skeleton,providing ef-fective support for the load growth of FNC on its surface.Sample S3,the FNC/RGO/MDCF composite prepared by solvothermal method for 16 h,exhibited a minimum reflection loss(RL_(min))of-66.44 dB at a thickness of 2.29 mm.When the thickness was reduced to 1.50 mm,the optimal effective absorption bandwidth was 3.84 GHz.Analysis of the absorption mechanism of FNC/RGO/MDCF revealed that its excellent absorption performance was primarily attributed to the combined effects of conduction loss,multiple reflection,scattering,in-terface polarization,and dipole polarization.
基金supported by the Science and Technology Department of Qinghai Province,China(No.2022-ZJ-932Q).
文摘The increase in the utilization of infrared heat detection technology in military applications necessitates research on composites with improved thermal transmission performance and microwave absorption capabilities.This study satisfactorily fabricated a series of MoS_(2)/BN-xyz composites(which were characterized by the weight ratio of MoS_(2)to BN,denoted by xy:z)through chemical vapor depos-ition,which resulted in their improved thermal stability and thermal transmission performance.The results show that the remaining mass of MoS_(2)/BN-101 was as high as 69.25wt%at 800℃under air atmosphere,and a temperature difference of 31.7℃was maintained between the surface temperature and the heating source at a heating temperature of 200℃.Furthermore,MoS_(2)/BN-301 exhibited an im-pressive minimum reflection loss value of-32.21 dB at 4.0 mm and a wide effective attenuation bandwidth ranging from 9.32 to 18.00 GHz(8.68 GHz).Therefore,these simplified synthesized MoS_(2)/BN-xyz composites demonstrate great potential as highly efficient con-tenders for the enhancement of microwave absorption performance and thermal conductance.
