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Trimetallic MOFs derived NiFe_(2)O_(4)/MoNi_(4)-NC Schottky heterojunctions with abundant defects and dielectric-magnetic coupling for electromagnetic response 被引量:1
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作者 Ya Ning Xiao Jiang +2 位作者 Jun Huang Yanfeng Gao Xiaojun Zeng 《Journal of Materials Science & Technology》 2025年第10期1-13,共13页
There is limited research reported on the multiple loss mechanism of electromagnetic waves(EMW)and the development of interface models.Dielectric loss and magnetic loss,as the two primary attenuation mechanisms in EMW... There is limited research reported on the multiple loss mechanism of electromagnetic waves(EMW)and the development of interface models.Dielectric loss and magnetic loss,as the two primary attenuation mechanisms in EMW absorbers,still pose challenges,especially in elucidating the correlation between composition,morphology,interface,and performance.Here,we construct 3D hierarchical porous conducting network structures and Schottky heterojunctions(MoNi_(4)@NC-NiFe_(2)O_(4)@NC)with a high density of defects,using trimetallic NiMoFe-MOFs.Synergistic enhancement of the dielectric and magnetic losses is realized through manipulation of the defects,interfaces,phase engineering,and magnetic resonance.In particular,the even dispersion of magnetic MoNi_(4) and NiFe_(2)O_(4)nanoparticles(NPs)within the carbon matrix triggers the creation of multiple heterogeneous interfaces.These inseparable interfaces,along with oxygen vacancies,play a role in enhancing dielectric polarization,while the closely spaced interactions among magnetic units contribute to magnetic loss.After optimizing the interfacial structure,NiFe_(2)O_(4)/MoNi_(4)-NC exhibits remarkable EMW absorption properties.A reflection loss(RL)value of-67.91 dB can be achieved at an ultra-thin thickness of 1.95 mm,and the effective absorption bandwidth(EAB,RL≤-10 dB)is as high as 5.76 GHz.Furthermore,we conducted radar scattering cross-section(RCS)simulations using computer simulation technology(CST)software,which revealed that NiFe_(2)O_(4)/MoNi_(4)-NC exhibits an RCS reduction value of 39.1 dB m^(2).Hence,this work provides comprehensive guidance for the construction of Schottky heterojunctions for lightweight EMW absorbers from a mechanistic point of view. 展开更多
关键词 Trimetallic NiMoFe-MOFs Multiple loss mechanisms Heterogeneous interfaces Schottky heterojunctions electromagnetic response
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The electromagnetic response of composition-regulated honeycomb structural materials used for broadband microwave absorption 被引量:11
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作者 Huifang Pang Yuping Duan +4 位作者 Xuhao Dai Lingxi Huang Xuan Yang Tuo Zhang Xiaoji Liu 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2021年第29期203-214,共12页
The undesirable absorption bandwidth is the main limitation for the application of microwave absorbing materials.Noting that the design of structure and composition of absorbing coating allows it to obtain a satisfyin... The undesirable absorption bandwidth is the main limitation for the application of microwave absorbing materials.Noting that the design of structure and composition of absorbing coating allows it to obtain a satisfying absorption bandwidth and to avoid weight increasing,honeycomb and its sandwich structures coated by various absorbant have been developed and measured using an arch measurement system over2-18 GHz.To further understand the absorption mechanisms of honeycomb structural materials,simulation based on finite element method and transmission line theory is performed to analyze the different responses to the applied microwave between honeycomb structural materials and uniform-medium slab materials.The proper composition design allows control over the microwave loss mechanisms,which optimize the coating to possess both of the dielectric and magnetic advantages.For the honeycomb structural materials,the magnetic resonation is found for the first time,which is resulting from the periodic honeycomb walls on both sides of the dielectric cavity(consisting of the aramid paper interlayer and vacuum hexagonal prisms).In addition,the conversion of structure from solid to honeycomb brings about changes in impedance,propagating path,effective wavelength,effective attenuation area,microwave phases,and inductive coupling effect,etc.,which result in a better microwave absorbing performance.The honeycomb sandwich structure coated by CIP/CB/EP with the weight ratio of 4:0.03:1 shows the absorption bandwidth of~9.8 GHz for reflection loss(RL)lower than-10 dB which covers part of the S and C bands and almost the whole X and Ku bands. 展开更多
关键词 Microwave absorption Structural materials HONEYCOMB electromagnetic response
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Crystal structure and electromagnetic responses of tetragonal GdAlGe
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作者 Cong Wang Yong-Quan Guo +1 位作者 Tai Wang Shuo-Wang Yang 《Chinese Physics B》 SCIE EI CAS CSCD 2020年第12期469-474,共6页
The ternary rare-earth aluminum germanide GdAlGe with tetragonal structure is systematically studied by x-ray diffraction,magnetic and electric measurements.The magnetic and electric properties of GdAlGe are strongly ... The ternary rare-earth aluminum germanide GdAlGe with tetragonal structure is systematically studied by x-ray diffraction,magnetic and electric measurements.The magnetic and electric properties of GdAlGe are strongly related to its special magnetic structure formed by magnetic Gd3 isosceles triangles△s.The GdAlGe orders ferromagnetically at 21 K due to the exchanging interaction of Gd3△↑-△↑Gd3.The mechanism of magnetic transport originates from the slip scattering induced by Stoner spin fluctuation in the magnetic ordering region and the spin wave scattering induced by the thermal photon excitation and phonon scattering in the paramagnetic region.The positive magnetoresistance is observed in GdAlGe,which might be due to the disordered magnetic scatter induced by magnetic anisotropy in GdAlGe. 展开更多
关键词 GdAlGe Weyl semimetal magnetic isosceles triangle electromagnetic response
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High-frequency gravitational waves having large spectral densities and their electromagnetic response
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作者 李芳昱 文毫 方祯云 《Chinese Physics B》 SCIE EI CAS CSCD 2013年第12期104-112,共9页
Various cosmology models, brane oscillation scenarios, interaction of interstellar plasma with intense electromagnetic radiation, and even high-energy physics experiments (e.g., Large Hadron Collider (LHC)) all pr... Various cosmology models, brane oscillation scenarios, interaction of interstellar plasma with intense electromagnetic radiation, and even high-energy physics experiments (e.g., Large Hadron Collider (LHC)) all predict high frequency gravitational waves (HFGWs, i.e., high-energy gravitons) in the microwave band and higher frequency region, and some of them have large energy densities. Electromagnetic (EM) detection to such HFGWs would be suitable due to very high frequencies and large energy densities of the HFGWs. We review several typical EM detection schemes, i.e., inverse Gertsenshtein effect (G-effect), coupling of the inverse G effect with a coherent EM wave, coupling of planar superconducting open cavity with a static magnetic field, cylindrical superconducting closed cavity, and the EM sychro-resonance system, and discuss related minimal detectable amplitudes and sensitivities. Furthermore, we give some new ideas and improvement ways enhancing the possibility of measuring the HFGWs. It is shown that there is still a large room for improvement for those schemes to approach and even reach up the requirement of detection of HFGWs expected by the cosmological models and high-energy astrophysical process. 展开更多
关键词 high-frequency gravitational waves electromagnetic response of high-frequency gravitational waves superconducting microwave cavities synchro-resonance system
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Electromagnetic response function for the semi-annual variations estimated by the single-station method using the night-time values of the geomagnetic fields
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作者 陈伯舫 《Acta Seismologica Sinica(English Edition)》 CSCD 2000年第3期316-324,共9页
The geomagnetic night-time values were used to estimate the electromagnetic response function Q1 for half-year period. If the spatial structure of the source field can be described by the approximation, one can estim... The geomagnetic night-time values were used to estimate the electromagnetic response function Q1 for half-year period. If the spatial structure of the source field can be described by the approximation, one can estimate the Q1 value using the single-station Z/H method. This technique enables us to carry out regional deep gcomagnetic sounding by the method. The data used for analyses are geomagnetic night-time values for about, typically, 26 years from 5 good-quality stations and for several years from 34 stations distributed over the globe. The results indicate that the night-time values yield more reliable response estimates for half-year period compared to the usual estimates obtained from daily means. It implies that the approximation for the night-time fields holds good for the half-year period, but the daily means are not suitable for estimating the response function of the semi-annual variations by using the single-station method. Source field analyses for daily means data and night-time means data have also been carried out in this paper. 展开更多
关键词 geomagnetic night-time data semi-annual variations electromagnetic response functions single-station Z/H method
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MXene Hybridized Polymer with Enhanced Electromagnetic Energy Harvest for Sensitized Microwave Actuation and Self‑Powered Motion Sensing
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作者 Yu‑Ze Wang Yu‑Chang Wang +3 位作者 Ting‑Ting Liu Quan‑Liang Zhao Chen‑Sha Li Mao‑Sheng Cao 《Nano-Micro Letters》 SCIE EI CAS 2025年第3期265-279,共15页
Polymeric microwave actuators combining tissue-like softness with programmablemicrowave-responsive deformation hold great promise for mobile intelligentdevices and bionic soft robots. However, their application is cha... Polymeric microwave actuators combining tissue-like softness with programmablemicrowave-responsive deformation hold great promise for mobile intelligentdevices and bionic soft robots. However, their application is challenged by restricted electromagneticsensitivity and intricate sensing coupling. In this study, a sensitized polymericmicrowave actuator is fabricated by hybridizing a liquid crystal polymer with Ti3C2Tx(MXene). Compared to the initial counterpart, the hybrid polymer exhibits unique spacechargepolarization and interfacial polarization, resulting in significant improvements of230% in the dielectric loss factor and 830% in the apparent efficiency of electromagneticenergy harvest. The sensitized microwave actuation demonstrates as the shortenedresponse time of nearly 10 s, which is merely 13% of that for the initial shape memory polymer. Moreover, the ultra-low content of MXene (upto 0.15 wt%) benefits for maintaining the actuation potential of the hybrid polymer. An innovative self-powered sensing prototype that combinesdriving and piezoelectric polymers is developed, which generates real-time electric potential feedback (open-circuit potential of ~ 3 mV) duringactuation. The polarization-dominant energy conversion mechanism observed in the MXene-polymer hybrid structure furnishes a new approachfor developing efficient electromagnetic dissipative structures and shows potential for advancing polymeric electromagnetic intelligent devices. 展开更多
关键词 Microwave absorption electromagnetic response Energy harvest SELF-SENSING Soft actuator
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Experimental study on transient electromagnetic conductivity logging in cased well
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作者 Shen Yong-Jin Su Yuan-Da 《Applied Geophysics》 2025年第2期422-431,558,共11页
A cased well model consists of a coaxial tank and casing,which houses coaxially installed transmitting and receiving coils.The transmitting coil is excited by the current produced by the transmitting circuit,and trans... A cased well model consists of a coaxial tank and casing,which houses coaxially installed transmitting and receiving coils.The transmitting coil is excited by the current produced by the transmitting circuit,and transient electromagnetic responses occur in the casing,including direct coupling and casing responses.As the range between the transmitting and receiving coils increases,direct coupling responses decay rapidly,are less than the casing response at 0.3 m,and disappear at 0.7 m.By contrast,a casing response increases rapidly and then declines slowly after reaching a peak and changes little within a specifi c range.The peak decreases slowly with range.The continuous addition of water to the tank causes slight changes in transient electromagnetic responses,so the diff erence which are subtracted from the response without water is used.Moreover,the diff erences at the time of rapid increase in response and the time of rapid decrease in response are large,forming a peak and a trough.Given that the conductivity of water in a full tank changes after the addition of salt,the diff erence in the peak is linear with the increase in the conductivity of water.This result provides an experimental basis for the design of a transient electromagnetic logging instrument that measures the conductivity of formation in cased well. 展开更多
关键词 transient electromagnetic response cased well conductivity logging COIL model experiment
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Comparison of the time-domain electromagnetic field from an infinitesimal point charge and dipole source 被引量:3
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作者 周楠楠 薛国强 王贺元 《Applied Geophysics》 SCIE CSCD 2013年第3期349-356,359,共9页
An electromagnetic field is generated through the accelerating movement of two equal but opposite charges of a single dipole. An electromagnetic field can also be generated by a time-varying infinitesimal point charge... An electromagnetic field is generated through the accelerating movement of two equal but opposite charges of a single dipole. An electromagnetic field can also be generated by a time-varying infinitesimal point charge. In this study, a comparison between the electromagnetic fields of an infinitesimal point charge and a dipole has been presented. First, the time-domain potential function of a point source in a 3D conductive medium is derived. Then the electric and magnetic fields in a 3D homogeneous lossless space are derived via the relation between the potential and field. The field differences between the infinitesimal point charge and the dipole in the step-off time, far-source, and near-source zones are analyzed, and the accuracy of the solutions from these sources is investigated. It is also shown that the field of the infinitesimal point charge in the near-source zone is different from that of the dipole, whereas the far-source zone fields of these two sources are identical. The comparison of real and simulated data shows that the infinitesimal point charge represents the real source better than the divole source. 展开更多
关键词 Infinitesimal point charge dipole source TIME-DOMAIN electromagnetic response near-source zone.
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Morphology-controlled CoNi/C hybrids with bifunctions of efficient anti-corrosion and microwave absorption 被引量:8
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作者 Jianwen Ge Yu Cui +3 位作者 Jiaxin Qian Li Liu Fandi Meng Fuhui Wang 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2022年第7期24-35,共12页
Till now,fewer literatures have investigated the corrosion resistance of microwave absorbers,especially mental@C/carbon matrix derived from MOF composites,although it is known that carbon shells possess a protective e... Till now,fewer literatures have investigated the corrosion resistance of microwave absorbers,especially mental@C/carbon matrix derived from MOF composites,although it is known that carbon shells possess a protective effect.Herein,three kinds of morphology-controlled CoNi/C-N doped architectures were suc-cessfully fabricated via a sequence of processing,namely coprecipitation for ZIF-67,subsequent Ni^(2+) ex-change and ultimate carbonization.Apart from composition characterization,the effects of microstructure tailoring and temperature controlling on electromagnetic response as well as attenuation performance were revealed,where dodecahedron-shaped composites possessed the highest permittivity.By contrast,rod-shaped composites(CoNi/C-r-550 and CoNi/C-r-700)were endowed with superior comprehensive ab-sorption properties,e.g.,RL_(min):-49.8 dB and-64.0 dB;EAB:5.7 GHz and 4.8 GHz,respectively.Besides,samples CoNi/C-d-700 and CoNi/C-r-700 present higher corrosion potential(E_(corr))and lower corrosion current(I corr).Hence,these corrosion-resistant microwave absorbers with outstanding absorption stabil-ity,wetting effect as well as environmental adaptability,can be used as a candidate/raw material for intelligent devices. 展开更多
关键词 electromagnetic response Morphological-anisotropic ANTICORROSIVE ZIF-67
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Carrier Density and Plasma Frequency of Alummum Nanofilms
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作者 HaoDU JunGONG +4 位作者 ChaoSUN RongfangHUANG lISHIWEN W.Y.Cheung S.P.Wong 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2003年第4期365-367,共3页
In this work, the prerequisite and mode of electromagnetic response of Al nanof ilms to electromagnetic wave field was suggested. Reflectance, transmittance in infrared region and carrier density of the films was meas... In this work, the prerequisite and mode of electromagnetic response of Al nanof ilms to electromagnetic wave field was suggested. Reflectance, transmittance in infrared region and carrier density of the films was measured. With the carrier density of the films, the dependence of their plasma frequencies on the film thickness was obtained. On the other hand, the dependence of absorptance on the frequency of electromagnetic wave field was set up by using the measured reflectance and transmittance, which provided plasma frequency-film thickness relation as well. Similarity of both plasma frequency-film thickness relations proved plasma resonance as a mode of electromagnetic response in Al nanofilms. 展开更多
关键词 Aluminum nanofilm electromagnetic response Size effect
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Design strategies for wave-absorbing polymer-based electromagnetic shielding materials:a review
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作者 Yehan Yang Ruhui He +2 位作者 Le Yang Hao Zhang Zhu Luo 《Science China Materials》 2025年第6期1735-1756,共22页
Traditional electromagnetic shielding materials primarily enhance reflection and absorption losses by increasing conductivity.While this approach improves shielding effectiveness,it also leads to issues such as impeda... Traditional electromagnetic shielding materials primarily enhance reflection and absorption losses by increasing conductivity.While this approach improves shielding effectiveness,it also leads to issues such as impedance mismatch,increased surface reflectivity,and irreversible secondary electromagnetic pollution.Consequently,the development of environmentally friendly electromagnetic interference(EMI)shielding materials with high efficiency and low reflectivity has become a key focus of research.This review examines the critical evaluation criteria and factors that influence the performance and reflectivity of EMI shielding materials.It also highlights recent advances in material tuning mechanisms and structural design strategies for the development of low-reflectivity,sustainable EMI shielding materials.By integrating material and structural design considerations,this review provides a comprehensive overview of strategies for constructing polymer-based low-reflectivity shielding materials,identifies persistent challenges in material design,and discusses future research directions in this field. 展开更多
关键词 low reflectivity electromagnetic interference shielding structural design polymer matrix composites electromagnetic response
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