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The absorbing properties of Fe_(73.5) Cu_1 Nb_3Si_(13.5)B_9 amorphous powder/S-glass fiber-reinforced epoxy composite panels

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Rare Metals 2013年第3期32卷 294-298页

作者： Xia-Lian Zheng Zheng-Hou Zhu Xiao-Min Li School of Materials Science and Engineering Nanchang University Physics Science and Engineering Technology Institute Yichun College

Fe73.5Cu1Nb3Si13.5B9 （or FeCuNbSiB） powder/ S-glass fiber-reinforced epoxy composite panels were pre- pared by mold pressing method. Metallographic analysis shows that the amorphous powders are evenly distributed between the layers of S-glass fibers. The effects of the Fe- CuNbSiB powder mass fraction on the complex permittivity, complex permeability, and microwave absorption of the composite panels have been studied in the frequency range of 2.6-18.0 GHz. The complex permittivity of the composite panels with different mass fractions of the FeCuNbSiB powders shows several peaks in the 2.6-18.0 GHz fre- quency range. The complex permeability of the composites decreases with the increasing frequency in the frequency range of 8-18 GHz. The composite with FeCuNbSiB/epoxy mass ratio of 2.5：1.0 has excellent microwave absorption properties of a minimum reflection loss value -30.5 dB at 10.93 GHz for a thickness of 2 mm. A reflection loss exceeding -10 dB can be obtained in a broad frequency range of 3.2-18.0 GHz with a thickness of 1.15-5.00 mm. For the FeCuNbSiB composites, the magnetic loss is the dominant term for microwave absorption. The FeCuNbSiB powders are a possible candidate for high-performance microwave absorption filler.

关键词： Amorphous powders Composites Permeability Permittivity absorbing properties

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Electroless plating of carbon nanotubes and their millimeter-wave absorbing properties

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Journal of Beijing Institute of Technology 2012年第4期21卷 551-557页

作者：尹艳华付民赵京磊王春芳 The Institute of Ecosystem Industry School of Chemical Engineering and EnvironmentBeijing Institute of Technology

A method of electroless plating was utilized to deposit Cu, Ni, Co, Ag on the surface of carbon nanotubes （CNTs） respectively, in order to prepare millimeter-wave absorbing materials. Field emission scanning electron microscope （FE-SEM） and energy dispersive spectrometer （EDS） were used to observe morphologies and chemical compositions of the samples respectively. Millime- ter-wave radiometer imaging detection was employed to measure the absorbing properties of the sam- ples. FE-SEM and EDS results demonstrate the effectiveness of successful metal deposition. The re- suits of millimeter-wave radiometer imaging detection reveal that the millimeter-wave absorbing properties of electroless-silver plating are better than other kinds of samples.

关键词： carbon nanotubes electroless plating millimeter wave absorbing properties

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Engineering of dielectric composites on electromagnetic and microwave absorbing properties for operation in the X-band

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Journal of Advanced Dielectrics 2021年第1期11卷 1-5页

作者： Bhoopendra Singh Vivek Pratap Mohit Katiyar S.M.Abbas Y.K.Sharma A.M.Siddiqui N.Eswara Prasad Department of Postgraduate Studies and Research in Physics and Electronics Rani Durgavati Vishwavidyalaya Jabalpur Madhya Pradesh Pachpedi Jabalpur 482001 Madhya PradeshIndia Department of Physics Jamia Millia Islamia Jamia Nagar New Delhi 110025NCT DelhiIndia Defence Materials and Stores Research and Development Establishment(DMSRDE)PO DMSRDE GT RoadKanpur 208013Uttar PradeshIndia

In this study,carbon black(CB)powder-loaded polyurethane(PU)composites(CB-PU composites)were prepared by melt mixing method with different volume percentages(45,50,55,58 and 61 vol.%)of CB in the PU *** prepared CB-PU composites had been further studied for surface morphology using the field-emission scanning electron microscopy(FESEM)*** properties in terms of real permittivity(ε′)and imaginary permittivity(ε′′)of the fabricated composites were computed using an Agilent E8364B vector network analyzer in the frequency range of 8-12 GHz(X-band).Dielectric loss factor of the prepared CB-PU composites was computed in terms of the dielectric loss tangent(tanδ_(e)=ε′′/ε′).Microwave absorbing properties were appraised in terms of the reflection loss(RL)which in turn was calculated for varying thicknesses of the prepared composites from the measured real and imaginary permittivity *** minimum RL was observed as−20.10 dB for the absorber with a thickness of 2.2 mm and the bandwidth achieved was 1.92 GHz for RL≤−10 *** on the above results these CB-PU composites have potential use as effective microwave absorbers in 8-12-GHz(X-band)frequency range.

关键词： Carbon black dielectric materials polymeric composites complex permittivity absorbing properties

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Physical-Chemical and Pharmacological Research on New Lignin Enterosorbent

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Journal of Pharmacy and Pharmacology 2014年第11期2卷 642-651页

作者： Mokhinur G. Ismailovat Khamida G. Yunuskhodjaeva Pazaat L. Ismailova Inessa B. Boyko Department of Biotechnology Tashkent Pharmaceuticallnstitute Tashkent 100015 Uzbekistan Laboratory on Natural Pharmaceuticals and Medical Sorbents Uzbek Chemical and Pharmaceutical Research Institute Tashkent100125 Uzbekistan Department of Pharmaco-toxicology Tashkent MedicalAeademy Tashkent 100047 Uzbekistan

The technology on obtaining enterosorbent from local feedstock--hydrolyzed lignin of cotton seed hulls named Zerotox was developed. The purpose of this research is to conduct a complex study on its physical-chemical and pharmacological properties. Samples of cotton hydrolyzed lignin based enterosorbent Zerotox were investigated, wood hydrolyzed lignin based enterosorbent Polifepan （Russia） was used as a comparison drug. The technology of new medical enterosorbent Zerotox, based on cotton hydrolyzed lignin, has been developed with its physical-chemical and pharmacological characteristics being researched. Comparative research on adsorbing capacity of sorbent Zerotox （80 mg/g） and its analogue--Polipefan （55 mg/g）, which is obtained from wood hydrolyzed lignin, has displayed advantages of the new sorbent. IR-spectroscopy research on lignin sorbent Zerotox has shown presence of oxygen-containing functional groups which determine its high absorbing capacity due to its chemisorption. Atomic-adsorptive method has proved high absorbing capacity of the sorbent towards heavy metals ions. Acute and chronic toxicity and antidiarrheal activity of enterosorbent Zerotox have also been studied.

关键词： Medical sorbents cotton hydrolyzed lignin detoxification absorbing properties adsorbing capacity functional groups atomic-adsorptive method pharmacological research.

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Li-Fe-O Nanocrystals Grown on Graphene: Synthesis and Their Electromagnetic Performance

Li-Fe-O Nanocrystals Grown on Graphene: Synthesis and Their ...

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中国化学会第九届全国无机化学学术会议

作者： Hong Wu Jin Tang Kangdi Lu Huifeng Li Genban Sun Xiaojing Yang College of Chemistry Beijing Normal University

Recently, the increasingly serious electromagnetic radiation and rapid development of stealth technology have put forward the severe test to synthetize new-type wave absorbing materials1. Lithium ferrites, especially Li Fe O2 and Li Fe5O8, as one of the most promising representative iron-based materials, with the advantage of environmental friendliness, low cost and light weight, are considered as the potential absorbing materials.2,3 Graphene is an excellent substrate due to its large surface area, high conductivity, and chemical stability, and also a kind of dielectric loss material.4 Hence, in order to meet the impedance matching of Zm=Z0（μr/ r）1/2, and obtain excellent absorbing performance, we constructed the composites of lithium ferrites（magnetic loss material） and graphene.5 Hereon, we firstly synthetized Li-Fe-O/graphene nanocomposites with high dispersity via a facile one-pot strategy under different reaction conditions and examined their electromagnetic performance. Different nanocrystals were assembled by simply controlling the reaction temperature and changing the solvent with the same precursors: when oleylamine was used as solvent, α-Li Fe O2 nanocrystals were obtained and when solvent was changed to NMP, β-Li Fe5O8 nanocrystals were formed. The as-formed β-Li Fe5O8 and α-Li Fe O2 nanocrystals with a diameter of ca. 5 and 7 nm, respectively, were densely and uniformly anchored on the graphene sheets. Compared with β-Li Fe5O8 and α-Li Fe O2 nanocrystals, the nanocomposites exhibit excellent microwave absorbability. By studying the mechanism of wave-absorption, we found that the size, crystal form and dispersity of the nanocrystals were associated with the absorbing properties.6

关键词： lithium ferrites graphene high dispersity absorbing properties nanocomposites

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