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Journal of Materials Science & Technology 2023年第13期144卷 81-92页

作者： Siyuan Zhang Jinlei Tao Rui Sun Shipeng Hu Jian Jiao Northwestern Polytechnical University Xi’an 710072China

Excellent impedance matching and high conduction loss are important factors for the preparation of high-performance electromagnetic wave(EMW)absorbing materials,but these two properties are of-ten *** this work,three absorbers with unique hollow structures,H-Ag/CuO@CuS,H-O-Ag/CuO@CuS,and H-P-Ag/CuO@CuS,are designed and synthesized by adopting hollow CuO@CuS with double shell as carrier and silver nitrate as the structural *** more voids coming from hol-low structures,window-opened structures,and stacked pores improve the impedance matching of these absorbers,and the introduction of elemental Ag effectively regulates the conduction ***,a balance between impedance matching and conduction loss is achieved to improve the reflection loss(RL)value and broadens the absorbing band of the *** comparison to H-Ag/CuO@CuS and H-O-Ag/CuO@CuS(hollow structure with open window)in which elemental Ag is uniformly dispersed in the CuO layer,H-P-Ag/CuO@CuS exhibits more excellent EMW absorption performance due to more voids and an optimized conductive network arising from Ag/CuO pieces distributed between the hol-low Ag/CuO@CuS particles and Ag distributed in the CuS *** the thickness is 2.3 mm,H-P-Ag/CuO@CuS provides an ultra-wide electromagnetic absorption band of 8.56 GHz(9.44-18 GHz),in which the RL<-10 dB and the minimum reflection loss of-41 dB.

关键词： Elemental sliver impedance matching Conduction loss Electromagnetic wave absorption

Synthesis of carbon-coated cobalt ferrite core-shell structure composite:A method for enhancing electromagnetic wave absorption properties by adjusting impedance matching

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Chinese Journal of Chemical Engineering 2022年第7期35卷 206-217页

作者： Jing Gao Zhijun Ma Fuli Liu Cunxin Chen School of Mining Liaoning Technical UniversityFuxin 123000China School of Chemical and Environmental Engineering China University of Mining and TechnologyBeijing 100083China

Cobalt ferrite has problems such as poor impedance matching and high density,which results in unsatisfactory electromagnetic wave(EMW)absorption *** this study,the CoFe_(2)O_(4)@C core-shell structure composite was synthesized by a two-step hydrothermal method.X-ray diffraction,transmission electron microscopy,Fourier transform infrared spectroscopy,thermogravimetric analysis,and vector network analysis et *** used to test the structure and EMW absorption properties of CoFe_(2)O_(4)@C *** results show that the reflection loss(RL)of the CoFe_(2)O_(4)@C composite reaches the maximum value of25.66 dB at 13.92 GHz,and the effective absorbing band(EAB)is 4.59 GHz(11.20-15.79 GHz)when the carbon mass content is 6.01%.The RL and EAB of CoFe_(2)O_(4)@C composite are increased by 219.55%and 4.59 GHz respectively,and the density is decreased by 20.78%compared with the cobalt *** enhanced EMW absorption properties of CoFe_(2)O_(4)@C composite are attributed to the attenuation caused by the strong natural resonance of the cobalt ferrite,moreover,the carbon coating layer adjusts the impedance matching of the composite,and the introduced dipole polarization and interface polarization can cause multiple Debye relaxation processes.

关键词： Cobalt ferrite Core-shell structure composite Electromagnetic wave absorption impedance matching

Rational design of hollow rice-grainedα-Fe_(2)O_(3)/carbon nanofibers with optimized impedance matching for electromagnetic wave absorption enhanced

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Nano Research 2023年第4期16卷 5676-5684页

作者： Jingshen Xu Na Lu Mengwei Yuan Genban Sun Beijing Key Laboratory of Energy Conversion and Storage Materials College of ChemistryBeijing Normal UniversityBeijing 100875China Center for Advanced Materials Research Beijing Normal UniversityZhuhai 519087China

Electromagnetic wave absorption materials are widely used in electronic equipment and military ***,high cost and complex preparation processes become a major obstacle in promoting popularization in the civil *** solve the problems above,researchers have made great efforts to develop Fe-based carbon ***,most of the typical composites require a high filling ratio while achieving excellent ***,in this study,carbon nanofibers(CNFs)combined with the hollow rice-grainedα-Fe_(2)O_(3)nanoparticles were prepared by the in-situ transformation *** rational microstructure design provided a solution for reducing the filling ratio,optimizing impedance matching,and improving electromagnetic wave absorption *** strong reflection loss value(−38.1 dB)and broad effective absorption bandwidth(4.6 GHz)for Fe_(2)O_(3)/CNFs composites were achieved with a low filling ratio(20 wt.%),and the analysis of electromagnetic parameters validated that the microstructure of Fe_(2)O_(3)/CNFs plays a crucial role in the performance *** the optimized impedance matching and simple preparation method,Fe_(2)O_(3)/CNFs have broad application prospects in electromagnetic wave absorption.

关键词： electromagnetic wave absorption Fe-based carbon nanofibers impedance matching

Optimizing impedance matching by a dual-carbon Co-regulation strategy of Co_(3)O_(4)@rGO/celery stalks derived carbon composites for excellent microwave absorption

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Journal of Materials Science & Technology 2023年第2期133卷 1-11页

作者： Xiubo Xie Yukun Wang Xueqin Sun Heshan Wang Ronghai Yu Wei Du Hongjing Wu School of Environmental and Material Engineering Yantai UniversityYantai 264005China MOE Key Laboratory of Material Physics and Chemistry under Extraordinary School of Physical Science and TechnologyNorthwestern Polytechnical UniversityXi’an 710072China Key Laboratory of Aerospace Materials and Performance(Ministry of Education) School of Materials Science and EngineeringBeihang UniversityBeijing 100191China

Both macroscopic composition and microstructure should be considered for reasonable microwave ab-sorbent *** this study,Co_(3)O_(4)@reduced graphene oxide(rGO)/Celery stalks derived carbon(CDC)was prepared by loading Co_(3)O_(4) particles into rGO and biomass-derived carbon mixture through oxidation *** changing the mass ratio of rGO to CDC,the dielectric and impedance matching proper-ties of the composites can be easily *** RL min value of Co_(3)O_(4)@rGO/CDC_(13) composite(weight ratio for rGO:CDC is 1:3)reaches-84.3 dB with a thickness of 4.6 mm,and the widest effective band-width can be obtained at 4.5 GHz with a matching thickness of 2.8 *** Co_(3)O_(4)@rGO/CDC_(13) compos-ite with multiple components(Co_(3)O_(4),CDC,rGO)and 3D net structure produces magnetic/dielectric loss combinations,interfacial polarization,and multiple reflections and scattering,and the CDC with half tube and half sheet structure is conducive to the optimization of impedance *** strategy of co-regulating dielectric properties of materials with double carbon provides a novel pathway for the prepa-ration of lightweight,low-cost,and high-performance absorbers.

关键词： Microwave absorption Graphene Co_(3)O_(4) Biomass carbon impedance matching

impedance matching for the reduction of signal reflection in high speed multilevel three-dimensional integrated chips

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Journal of Semiconductors 2014年第1期35卷 121-128页

作者：刘晓贤朱樟明杨银堂王凤娟丁瑞雪 School of Microelectronics Xidian University Key Laboratory of Wide Band-Gap Semiconductor Materials and Devices

In high speed three-dimensional integrated circuits （3D ICs）, through silicon via （TSV） insertion causes impedance discontinuities along the interconnect-TSV channel that results in signal reflection. As demonstrated for a two-plane interconnect structure connected by a TSV, we incorporate an appropriate capacitance at the junction to mitigate the signal reflection with gigascale frequencies. Based on 65 nm technology and S-parameter analysis, the decrease of signal reflection can be 189% at the tuned frequency of 5 GHz. Extending this method to the five-plane interconnect structure further, the reduction of signal reflection can achieve 400%. So we could broaden this method to any multilevel 3D interconnect structures. This method can also be applied to a circuit with tunable operating frequencies by digitally connecting the corresponding matching capacitance into the circuit through switches. There are remarkable improvements of the quality of the transmitting signals.

关键词： 3D integration TSV signal reflection impedance matching S-parameter

impedance matching Algorithm for Selection of Suitable Explosives for Any Rock Mass-A Case Study

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Journal of Geological Resource and Engineering 2020年第2期8卷 55-65页

作者： Ajay Kumar Jha BioID GmbH Nürnberg 90489Germany

Proper selection of the explosive is an important part of blast *** judicious selection of explosives is governed by economic considerations and site/field *** mine management desires to select an explosive that will give the lowest cost per unit of rock broken,while assuring that fragmentation,fragment size distribution,muck pile profile,muck pile diggability,displacement of the rock,onset of movement,face movement,burden relief rate,ground vibration and noise remains within control *** which influence the selection of an explosive include explosive cost,charge diameter,cost of drilling,fragmentation difficulties and fragment size requirement with loose muck pile condition,water conditions,atmospheric temperature,propagating ground,storage considerations,sensitivity considerations,explosive atmospheres and nearness of communities from *** these concerns can be handled effectively by using the impedance matching technology where explosive impedance is matched with rock impedance for optimal blast performance with due concern to productivity,economics and *** paper discusses a case study in limestone mines where rock impedance was determined by carrying out surface refraction test and a patented algorithm was used to estimate the explosives’properties ***(velocity of detonation)and density of explosives required.

关键词： Explosive selection impedance matching rock impedance explosive impedance

Adaptive impedance-matching with Quantum Genetic Algorithm and Quantum Interference

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Adaptive Impedance-Matching with Quantum Genetic Algorithm a...

Single-atom Zn confined in hierarchical hollow microstructure as an acid/base-resistant microwave absorption materials

第十四届全国容错计算学术会议(CFTC'2011)

作者： Chen Saihua~1 Tan Yanghong~2 Yi Rufang~3 Xiong Zhiting~4 College of Electrical & Information Engineering,Hunan Univ.,Changsha Hunan 410082,China

＜正＞In Radio Frequency（RF） systems,we often want to transmit maximum power to antennas. So impedance matching is vital for transmitter and receiver antennas,as antennas input impedances will vary with external application occasions.A Quantum Genetic Algorithm（QGA） is proposed to realize automatic antenna impedance matching with Pi-network on the basis of Conventional Genetic Algorithm（CGA）.In this proposed QGA,we adopted real code *** cumulative effect of quantum rotation operation and a quantum interference strategy are also adopted thus the program converges to its balance points in real time. Experiment results indicate that the QGA is characterized of effective,high efficiency and time saving,and can avoid premature.

关键词： impedance matching CGA QGA

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Nano Research 2024年第8期17卷 6785-6794页

作者： Yue Lou Jiao Li Xiaokun Li Zhenyu Zhu Zhan Shi Biao Xu School of Chemistry and Chemical Engineering Nanjing University of Science and TechnologyNanjing 210094China State Key Laboratory of Inorganic Synthesis and Preparative Chemistry College of ChemistryJilin UniversityChangchun 130012China

Developing acid/base-resistant and low-price microwave-absorbing materials with lighter weight is highly desired for practical applications in extreme ***,we demonstrate the successful synthesis of the N-doped porous carbon(NC)material with hierarchical pore structure by the spray pyrolysis *** large specific surface area(SBET=707.53 m^(2)·g^(−1))of materials enables multiple scattering of incident electromagnetic waves,and N doping greatly enhances the electrical conductivity of the ***,single-atom Zn can adjust the local electronic structure of adjacent sites such as carbon and nitrogen atoms,induce the center of polarization,and thus change the dielectric and electronic properties of the host *** porous carbon coating of single-atom Zn avoids the deterioration of electromagnetic parameters caused by the accumulation of magnetic particles under high-temperature *** the same time,they can also be used in various complex environments,such as acidic and basic ***,NC-1000,with high surface area,low density,and good chemical stability,obtained a minimum reflection loss(RLmin)of−50.5 dB and an effective absorption bandwidth(EAB)exceeding 5.1 GHz at the thickness of 1.9 *** soaking in the strong acid and base solution,the electromagnetic wave absorption performance of the material decreased by<15%.Widely available raw materials and a simple preparation scheme are expected to expedite industrial mass production for this novel type of materials.

关键词： hierarchical hollow microstructure microwave absorption metal-organic framework(MOF) impedance matching singleatom Zn acid/base-resistant

Flower-like CuS/γ-Fe_(2)O_(3) van der Waals heterostructures with highefficient electromagnetic wave absorption

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Nano Research 2024年第4期17卷 3324-3333页

作者： Na Lu Jingshen Xu Mengwei Yuan Genban Sun Beijing Key Laboratory of Energy Conversion and Storage Materials Institution College of ChemistryBeijing Normal UniversityBeijing 100875China Center for Advanced Materials Research Beijing Normal UniversityZhuhai 519087China

The escalating electromagnetic(EM)pollution issues and the demand to elevate military stealth technology make it imperative to develop cost-effective and high-performance electromagnetic wave(EMW)absorbing *** this paper,the flower-like CuS/γ-Fe_(2)O_(3) van der Waals(vdW)heterostructures have been synthesized via a facile two-step solvothermal *** flower-like CuS skeleton increases the attenuation path of EMW while reducing the material *** contents ofγ-Fe_(2)O_(3) nanoparticles anchor between the flower-like CuS nanosheets to constitute a heterogeneous structure,which enables dielectric and magnetic loss synergistically to optimize impedance matching and remarkably improve the EMW absorption *** minimum reflection loss(RLmin)is-49.36 dB with a thickness of only 1.6 mm and the effective absorption bandwidth(EAB)reaches 4.64 GHz(13.36–18 GHz).By adjusting the thickness of the absorber,the EAB can cover 96%of the GHz ***,the superior absorption of-61.53 dB at middle frequency band can be obtained by adjusting the amount of Fe_(2)O_(3) *** this study,the adjustment of EM parameters and the optimization of impedance matching have been achieved by constructing a novel vdW heterogeneous structure,which provides fresh ideas and references for the design of high-performance EMW absorbing materials.

关键词： flower-like CuS γ-Fe_(2)O_(3) van der Waals heterostructures impedance matching electromagnetic wave absorption

Facile fabrication of graphene/g-C_(3)N_(4) for electromagnetic wave absorption

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Nano Research 2024年第3期17卷 1687-1698页

作者： Qiang Su Yunfei He Dongdong Liu Daguang Li Long Xia Xiaoxiao Huang Bo Zhong School of Materials Science and Engineering Harbin Institute of Technology WeihaiWeihai 264209China Weihai Yunshan Technology Co. Ltd.Weihai 264200China State Key Laboratory on Integrated Optoelectronics College of Electronic Science&EngineeringJilin UniversityChangchun 130012China School of Materials Science and Engineering Harbin Institute of TechnologyHarbin 150001China

With the development of the miniaturization of electronic equipment and lightweight weapon equipment,there are new requirements for electromagnetic wave absorption material(EMWAM).EMWAM has outstanding electromagnetic wave absorption properties and lightweight characteristics become an important direction of *** this study,graphene/g-C_(3)N_(4)(GGCN)EMWAM was first synthesized in situ by simple heat treatment,in which the g-C_(3)N_(4) had a porous structure and dispersed on the surface of *** impedance matching of the GGCN was well adjusted by decreasing the dielectric constant and attenuation constant due to the g-C_(3)N_(4) semiconductor property and the graphite-like *** EMW loss mechanism of GGCN was also analyzed by simulating GGCN’s electric field mode distribution and resistance loss power *** analysis result shows that the distribution of g-C_(3)N_(4) among GGCN sheets can produce more polarization effects and relaxation effects by increasing the lamellar ***,the polarization loss of GGCN could be increased successfully by porous g-C_(3)N_(4).Ultimately,the EMW absorption property of GGCN is optimized significantly,and GGCN exhibits excellent EMW absorption *** the thickness is 2 mm,the effective absorption bandwidth(EAB)can reach 4.6 GHz,and when the thickness is 4.5 mm,the minimum reflection loss(RLmin)at 4.56 GHz can reach-34.69 ***,the practical application of EMWAM was studied by radar cross-section(RCS)simulation,showing that GGCN has a good application prospect.

关键词： graphene/g-C_(3)N_(4) impedance matching simulation analysis dielectric loss excellent electromagnetic wave absorption