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The Influence of magnetic permeability on the Configuration of magnetic Field in Helimak Device

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Plasma Science and Technology 2003年第3期5卷 1799-1802页

作者：陈文革武松涛 Institute of Plasma Physics Chinese Academy of SciencesHefei 230031China

The Helimak of USA is a plasma physics experimental device designed and built by CASIPP. Its configuration of magnetic field is of very importance during the operation of this device. In this paper, the influence of magnetic permeability on configuration of magnetic field will be discussed due to the effect of weld metal in the vacuum vessel of Helimak, and some conclusion is useful for some engineering designs of the fusion experimental device.

关键词： magnetic permeability configuration magnetic field

Tappet Chill Depth Measuring by magnetic permeability and Inductance Displacement Meter

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Journal of Iron and Steel Research(International) 2001年第2期8卷 59-60页

作者： ZENG Hui WANG Xue-hua YAN Chun Wuhan University of Technology

It is possible to measure different position along the axle direction of tappet.According to the maximum output of signal,the boundary of white iron structure and mottled iron structure can be deduced,and at the same time,it is possible to use inductance displacement meter to show the chill depth which is the distance from the boundary to the end.

关键词： magnetic permeability chilled cast iron chill depth

调控磁导率以优化高熵合金的自旋电子排列实现高效析氧反应

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Science China Materials 2024年第2期67卷 598-607页

作者：陈正杰张涛吴佳静杨新春郑勇平唐永炳于海滨彭晶成会明 Faculty of Materials Science and Energy Engineering Institute of Technology for Carbon NeutralityShenzhen Institute of Advanced TechnologyChinese Academy of SciencesShenzhen 518055China Wuhan National High magnetic Field Center&School of Physic Huazhong University of Science and TechnologyWuhan 430074China Institute of Information Technology Shenzhen Institute of Information TechnologyShenzhen 518172China Shenzhen Key Laboratory of Energy Materials for Carbon Neutrality Shenzhen Institute of Advanced TechnologyChinese Academy of SciencesShenzhen 518055China Shenyang National Laboratory for Materials Science Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China

磁场触发的催化剂轨道电子自旋排列已成为促进析氧反应的一种有趣而可行的策略.然而,具有强d-d库仑相互作用的高熵合金(HEAs)催化剂中的磁场增强机制尚未得到充分挖掘.在此,我们设计了具有优异软磁性的高熵合金金属片,在微小磁场下表现... 详细信息

磁场触发的催化剂轨道电子自旋排列已成为促进析氧反应的一种有趣而可行的策略.然而,具有强d-d库仑相互作用的高熵合金(HEAs)催化剂中的磁场增强机制尚未得到充分挖掘.在此,我们设计了具有优异软磁性的高熵合金金属片,在微小磁场下表现出显著的磁场增强催化作用,其磁导率可作为评估磁场增强的描述因子.具体地,仅施加50 mT的磁场,(FeCoNi)_(82.5)Cr_(17.5)HEAs的过电位下降就超过了36mV@10 mA cm^(-2).此外,过电位的降低与HEA的磁导率呈线性关系.原位拉曼光谱与理论计算结果表明,施加磁场可显著提高自旋密度,改善催化剂的3d电子与*O自由基的2p轨道之间的自旋相互作用,从而有效降低速率决定步骤(*O→*OOH)的能量障碍,进而促进O-O的形成.

关键词： high-entropy alloy magnetic permeability magnetic field spin arrangement oxygen evolution reaction

Microwave Absorbing Properties of Polymer Composites Containing High-permeability magnetic Flake Particles in Quasi-microwave Frequency Band

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Microwave Absorbing Properties of Polymer Composites Contain...

Enhanced Microwave Absorption for High Filler Content Composite Molded from Polymer Coated Flaky Carbonyl Irons Modified by Silane Coupling Agents

2012 International Conference on Nano Materials and Electric Devices(ICNMED 2012)

作者： Sung-Soo Kim Department of Advanced Materials Engineering Chungbuk National University

This study investigates high-frequency magnetic, dielectric, and microwave absorbing properties of Sendust（Fe-Si-Al alloy） flake particles dispersed in rubber matrix for the design of thin microwave absorbers in quasi-microwave frequency band. At high particle loading（92% in weight） in the magnetic composite, reflection loss of-9 d B was obtained at 2 GHz with a small thickness of 1 mm. The result is attributed to the high values of magnetic permeability and dielectric constant of the composites resulting from a low eddy current loss（increase of permeability） of the flake particles and enhancement of space charge polarization（increase of permittivity） between the metallic particles. However, the investigation of impedance matching reveals that the magnetic permeability is still small to satisfy the zero-reflected condition at the quasi-microwave frequency band of 1-2 GHz with a composite thickness smaller than 1 mm. It is suggested that greater magnetic permeability（by control of composition and shape of magnetic particles） is required for more improved microwave absorbance at a quasi-microwave frequency.

关键词： Microwave absorbers Sendust particles magnetic permeability Polymer composites

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Journal of Wuhan University of Technology(Materials Science) 2023年第1期38卷 42-51页

作者：崔正明 MA Guoqing WANG Mengqi LUO Chuangyu CHEN Zhihong MA Huiru LI Qifan 李维 State Key Laboratory of Advanced Technology for Materials Synthesis and Processing School of Materials Science and EngineeringWuhan University of TechnologyWuhan 430070China School of Science Wuhan University of TechnologyWuhan 430070China Department of Chemistry School of ChemistryChemical Engineering and Life ScienceWuhan University of TechnologyWuhan 430070China School of Physics and Electronic Science Hubei UniversityWuhan 430062China

A microwave absorbing sheet with a high complex permeability and a relatively low complex permittivity is obtained by molding of the densely coated flaky carbonyl iron particles(FCIPs)by styrenebutadiene-styrene block copolymer(SBS)in the assistance of coupling agent modification.Direct molding of the core-shell FCIPs without adding extra binder results in a large permeability due to the high filling ratio(55vol%)of absorbents.Importantly,the permittivity is well suppressed by the dense insulate polymer shell on the FCIPs,avoiding the severe impedance mismatch problem of the high filler content microwave absorbing materials.Investigations show that modifying the surface of FCIPs by proper amount of silane coupling agent is critical for the coating quality of the SBS shell,which is verified by resistivity and corrosion current density measurements,and can be interpreted by improved interfacial compatibility between the modified FCIPs and SBS.The obtained microwave absorbing sheet shows a minimum reflection loss of-38.74 dB at 1.57 GHz and has an effective absorption bandwidth from 1.1 to 2.3 GHz at a relatively small thickness of 2 mm.

关键词： microwave absorber coating quality magnetic permeability permittivity low frequency

Microstructural,magnetic and dielectric performance of rare earth ion(Sm^(3+))-doped MgCd ferrites

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Chinese Physics B 2022年第7期31卷 643-647页

作者：文丹丹陈霞骆大森卢毅陈一鑫黎人溥崔巍 Doctoral Research Station of Chongqing Key Laboratory of Optoelectronic Information Sensing and Transmission Technology Chongqing University of Post and TelecommunicationsChongqing 400065China State Key Laboratory of Electronic Thin Films and Integrated Devices University of Electronic Science and Technology of ChinaChengdu 610054China Chongqing Key Laboratory of Autonomous Navigation and Microsystem Chongqing University of Post and TelecommunicationsChongqing 400065China

The combined effects of Sm^(3+)substitution together with the addition of 3 wt%Bi_(2)O_(3)endow Mg Cd ferrites with excellent magnetic permeability and dielectric permittivity.Various concentrations of Sm^(3+)(x=0,0.03,0.06,0.09,0.12and 0.15)were employed to modify the permeability(μ)and permittivity(ε)of the Mg Cd ferrites.X-ray diffraction,scanning electron microscopy(SEM),vibrating sample magnetometry and vector network analysis techniques were used to characterize the samples.The measurement results reveal that the ferrites processed a saturation magnetization of up to 36.8 emu/g and coercivity of up to 29.2 Oe via the conventional solid-state reaction method.The surface morphology SEM confirms that with increasing Sm^(3+)concentration,the grain shape changes from a polygon to a circle.Moreover,the dielectric permittivity can reach a value of 23.The excellent properties obtained in Sm^(3+)-substituted Mg ferrites suggest that they could be promising candidates for modern high-frequency antenna substrates or multilayer devices.

关键词： ferrites Sm^(3+)ions substitution magnetic permeability dielectric permittivity

Fabrication and electromagnetic wave absorption properties of amorphous Ni-P nanotubes

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Chinese Physics B 2011年第6期20卷 139-144页

作者：陆海鹏韩满贵蔡黎邓龙江 State Key Laboratory of Electronic Thin Films and Integrated Devices University of Electronic Science and Technology of China

Amorphous Ni-P nanotubes are fabricated through electroless chemical deposition inside an anodic aluminum oxide template. The hysteresis loops of Ni-P nanotube arrays are each found to exhibit an unusual isotropic behaviour, which is believed to be due to the competition results between the shape anisotropy and the magnetostatic interaction among nanotubes. The dynamic dependence of permittivity on the frequency spectrum is fitted to the Lorentzian-type dispersion law. The permeability dispersion behaviours have been fitted based on the Kittel equation. Electromagnetic wave absorption properties of Ni-P nanotubes/paraffin composites with different values of thickness （t） are clearly shown by a three-dimensional graph. Furthermore, the bandwidths of composites with different ＂t＂ values can be well presented by a two-dimensional contour graph, which is a novel presentation form. The results show that the composites each have a good microwave absorption performance with t larger than 5.5 mm and with the frequency around 8 gigahertz.

关键词： magnetic permeability permittivity microwave absorber magnetic nanotubes

Dynamic parameters of Tb-Dy-Fe giant magnetostrictive alloy

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Journal of Rare Earths 2010年第1期28卷 104-108页

作者：白夏冰蒋成保 School of Materials Science and Engineering Beihang University

Tb0.3Dy0.7Fe1.90 oriented rods were prepared by zone melting with unidirectional solidification.The magnetomechanical coupling factor(k33) was measured by magnetomechanical resonance under different DC bias fields up to 77.4 mT.An effective method was provided to calculate sonic velocity,elastic modulus and compliance constant through measuring resonate frequency(fr),and calculate dynamic magnetostriction(d33) via measuring magnetic permeability,magnetomechanical coupling factor(k33) and complia...

关键词： sonic velocity elastic modulus compliance constant magnetic permeability dynamic magnetostriction rare earths

Electromagnetic wave absorbing properties and hyperfine interactions of Fe–Cu–Nb–Si–B nanocomposites

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Chinese Physics B 2014年第8期23卷 50-54页

作者：韩满贵郭韦吴燕辉刘明 Magundappa L. Hadimanic State Key Laboratory of Electronic Thin Films and Integrated Devices University of Electronic Science and Technology of China Analytical and Testing Center Sichuan University Department of Electrical and Computer Engineering Iowa State University

The Fe-Cu-Nb-Si-B alloy nanocomposite containing two ferromagnetic phases （amorphous phase and nanophase phase） is obtained by properly annealing the as-prepared alloys. High resolution transmission electron microscopy （HR- TEM） images show the coexistence of these two phases. It is found that Fe-Si nanograins are surrounded by the retained amorphous ferromagnetic phase. Mossbauer spectroscopy measurements show that the nanophase is the D03-type Fe- Si phase, which is employed to find the atomic fractions of resonant 57Fe atoms in these two phases. The microwave permittivity and permeability spectra of Fe-Cu-Nb-Si-B nanocomposite are measured in the frequency range of 0.5 GHz- 10 GHz. Large relative microwave permeability values are obtained. The results show that the absorber containing the nanocomposite flakes with a volume fraction of 28.59% exhibits good microwave absorption properties. The reflection loss of the absorber is less than -10 dB in a frequency band of 1.93 GHz-3.20 GHz.

关键词： Mossbauer spectroscopy magnetic permeability nanocrystalline alloys