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Rational construction of graphene oxide with MOF- derived porous NiFe@C nanocubes for high-performance microwave attenuation

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Nano Research 2016年第12期9卷 3671-3682页

作者： Zhihong Yang Hualiang Lv Renbing WU College of Materials Science and Technology Nanjing University of Aeronautics and Astronautics Nanjing 211100 China Department of Materials Science Fudan University Shanghai 200433 China

Exploring lightweight microwave attenuation materials with strong and tunable wideband microwave absorption is highly desirable but remains a significant challenge. Herein, three-dimensional （3D） porous hybrid composites consisting of NiFe nanoparticles embedded within carbon nanocubes decorated on graphene oxide （GO） sheets （NiFe@C nanocubes@GO） as high-performance microwave attenuation materials have been rationally synthesized. The 3D porous hybrid composites are fabricated by a simple method, which involves one-step pyrolysis of NiFe Prussian blue analogue nanocubes in the presence of GO sheets. Benefiting from the unique structural features that exhibit good magnetic and dielectric losses as well as a proper impedance match, the resulting NiFe@C nanocubes@GO composites show excellent microwave attenuation ability. With a minimum reflection loss （RL） of -51 dB at 7.7 GHz at a thickness of 2.8 mm and maximum percentage bandwidth of 38.6% for RL 〈 -10 dB at a thickness of 2.2 mm, the NiFe@C nanocubes@GO composites are superior to the previously reported state-of-the-art carbon-based microwave attenuation materials.

关键词： hybrid dielectric loss magnetic loss microwave attenuation

STUDIES OF THE VERTICAL STRUCTURE MODEL AND THE microwave attenuation OF CLOUDS AND PRECIPITATION OVER TROPICAL OCEAN AREA

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Acta meteorologica Sinica 1998年第4期12卷 400-409页

作者：张凌窦贤康刘锦丽 LAGEO Institute of Atmospheric Physics.Chinese Academy of Sciences.Beijing 100029 Dept.of Sciences of Earth and Space University of Science and Technology of China.Hefei 230026 LAGEO Institute of Atmospheric PhysicsChinese Academy of Sciences.Beijing 100029

Using radiosonde data and other related observations in the TOGA-COARE IOP(from November 1,1992 to February 28,1993),the microwave attenuation of non-precipitating clouds is investigated based on microwave radiative transfer model(MRTM)at the specific frequencies of 6.8,10.65,13.9,19.35,22.235,37.0,85.5 and 90.0 ***,utilizing the data of the airborne radar and radiometer at 13.8 GHz in the IOP(Intensive Observation Period),vertical structure models for different types of precipitating clouds are obtained,and also the microwave attenuation of precipitating cloud is *** statistical characteristics of 13.8 GHz microwave path integrated attenuation for stratiform and convective precipitating clouds are *** results given here are valuable for the spaceborne microwave remote sensing of precipitation,and the cloud and precipitation attenuation corrections in the spaceborne microwave remote sensing of earth surface over tropical ocean area.

关键词： spaceborne remote sensing microwave remote sensing microwave attenuation

Adjustable character of microwave attenuation in BaTiO3 electrorheological fluids

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Progress in Natural Science:Materials International 2002年第10期 35-40页

作者： FAN Jijun, ZHAO Xiaopeng , HUANG Min, GUAN Litao and WEN Lishi(1. Institute of Electrorheological Technology, 141# Northwestern Polytechnical University, Xi'an710072, China 2. Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110015, China) Institute of Electrorheological Technology 141# Northwestern Polytechnical University Xi'an 710072 China Institute of Metal Research Chinese Academy of Sciences Shenyang 110015 China

The behavior of microwave attenuation in BaTiO3 electrorheological fluids is studied when considering microwave propagation in the directions perpendicular and parallel to the particle chains, respectively. In the former case, the microwave attenuation increases with field strength when the particle concentration is low, and the increase of the particle concentration can also increase the microwave attenuation. However, when the particle concentration exceeds a critical value, the attenuation will first increase then decrease with field strength. At the same time, the higher the field strength, the greater the change of microwave attenuation. Moreover, there is a saturation field strength. When the field strength is lower than the saturated one, the change of microwave attenuation is fast. On the other hand, in the case of microwave propagation parallel to the particle chains, the microwave attenuation increases with the field strength monotonously. In addition, the variation of microwave attenuation wi

关键词： electrorheological fluids BaTiO3 microwave attenuation relaxation effect.

Computation of Electromagnetic Properties of Mildly Overexpanded and Underexpanded Rocket Exhaust Plume

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Journal of Beijing Institute of Technology 2000年第2期9卷 217-224页

作者：刘青云黄振宇张平徐文灿北京理工大学机电控制工程系北京100081

An improved near far field divided coupled method was established to investigate the electromagnetic properties of mildly overexpanded and underexpanded rocket exhaust plumes. Firstly, axisymmetric Navier Stokes equations incorporated with k ε two equation turbulence models were solved using time dependent approach to calculate the pressure of the near filed. Secondly, parabolized axisymmetric Navier Stokes equations incorporated with finite rate chemical kinetics models were marching on the detailed pressure map of the near field. The termination of the near field would yield the initial line for the far field. In addition, in the far field, the spatial marching method was directly used under the constant pressure condition, but considering more complicated chemically reacting process. Finally, the electromagnetic parameters of the whole plume were calculated with the electron conductive model. The calculated results of the overexpanded and underexpanded rocket exhaust plume were discussed. The predicted microwave attenuation accorded with the experimental results. This improved method is feasible for calculating the microwave attenuation characteristics of mildly non fully expanded rocket exhaust plumes.

关键词： rocket exhaust plume microwave attenuation numerical simulation

PREPARATION AND PROPERTIES OF ULTRAFINE COMPOSITE POWDERS OF Fe_3O_4 AND Ni/MICA

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China Particuology 2005年第3期3卷 187-190页

作者： YuchengWu JiaqinLiu RujunXue GuozhongWang LideZhang FacultyofMaterialsScienceandEngineering HefeiUniversityofTechnologyHefei230009P.R.China//InstituteofSolidStatePhysicsChineseAcademyofSciencesHefei230031P.R.China FacultyofMaterialsScienceandEngineering HefeiUniversityofTechnologyHefei230009P.R.China InstituteofSolidStatePhysics ChineseAcademyofSciencesHefei230031RR.China

This paper presents the preparation of ultrafine powders of Fe3O4 and Ni by a chemical method, followed by mixing the prepared powders with mica and other ultrafine powders for synthesizing microwave absorption coatings. The microwave attenuation rate of the coatings was measured by the microwave Network Analyzer in the frequency range of 8-12 GHz at room temperature. The results indicate that microwave could be absorbed by the coatings with an effectiveness strongly dependent on the powder sort and content and the coating thickness.

关键词： ultrafine powders coating microwave attenuation