共查询到19条相似文献,搜索用时 156 毫秒
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刘伟张捷张婷王东红雷忆三 《安全与电磁兼容》2017,(5):65-70
碳纳米材料具有独特的微观结构和介电性能,将这类材料与磁损耗材料复合可以有效提高吸波性能。从制备方法、吸波性能和吸波机理等方面,综述了石墨烯、碳纳米管、碳纳米纤维等碳纳米材料与磁性材料复合的吸波特性的最新研究成果,并对其发展前景进行了展望。 相似文献
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随着无线电通信技术和各种电子设备的广泛应用,电磁污染日益严重,具有三维多孔结构的电磁波吸收材料成为科学研究的热点。总结了碳基气凝胶复合材料的研究进展,详细介绍了石墨烯气凝胶、生物质衍生的碳气凝胶和聚合物衍生的碳气凝胶的多种制备方法,碳气凝胶与磁性颗粒、碳化硅、碳纳米管和MXene复合而成的复合碳基气凝胶吸波材料的吸波性能。简要阐述了吸波材料的损耗机理,讨论了碳基气凝胶复合材料的组分、微观结构和损耗机制对吸波性能的影响。最后,就目前研究现状总结了碳基气凝胶复合材料在制备和性能提升方面的挑战,展望了碳基气凝胶复合材料的研究重点和发展方向。 相似文献
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随着社会的快速发展和电子设备的普及,电磁辐射污染问题变得尤为突出,也带来了潜在的危害。因此,开发高效的电磁波吸收材料以解决电磁辐射污染问题迫在眉睫。铁基金属有机框架(Fe-MOFs)具有高度不饱和的铁金属中心离子和多样的结构类型。通过将Fe-MOFs作为前驱体进行碳化,可以制备出铁/铁氧化物/铁碳化物均匀分布的衍生碳基化合物。这些Fe-MOFs衍生碳基化合物表现出较高的介电损耗和磁损耗能力,可有效克服当前吸波材料存在的吸收频带窄、阻抗匹配性差等问题,成为近年来备受关注的一种新型吸波材料。首先简要介绍了电磁波吸收机制,然后综述了近年来关于单金属、双金属、三金属Fe-MOFs以及由Fe-MOFs与其他材料(包括碳材料、导电聚合物、MXene和生物质)复合制备的衍生碳基吸波材料的研究进展,最后对MOFs衍生碳基吸波材料的未来发展方向进行了展望。 相似文献
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作为单原子厚度的碳材料,石墨烯因具有低密度、高比表面积和电子迁移率的特性,易于满足吸波材料所需的要求。目前,单一的吸波材料难以达到多波段、宽频带的吸收效果,为了拓宽其红外吸收频带,通过将氧化石墨烯与纳米γ-Al2O3复合,并采用水合肼原位还原制备石墨烯基吸波材料。利用Raman、XRD、FT-IR、EDX和SEM对复合材料的结构与形貌进行了分析,同时测试了烟幕对1.06 m激光和8~12 m波段的红外消光特性,结果表明,石墨烯基吸波材料对红外激光系统以及红外热像仪均具有一定的干扰作用。 相似文献
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碳纳米管和石墨烯等新型碳纳米材料具有优异的电学、光学和力学特性,在柔性电子器件领域具有广阔的应用前景。从碳纳米材料的制备和器件的构建角度出发,本文介绍了基于碳纳米管和石墨烯的薄膜晶体管器件的最新研究进展。我们将已有碳基薄膜晶体管器件的构建方法分为固相法、液相法和气相法三类,重点讨论和比较了不同方法的技术特点和发展潜力,指出了碳纳米管和石墨烯材料在柔性电子器件领域中可能的实际应用前景和趋势展望。 相似文献
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复合多层吸波材料除具备“薄、轻、宽、强”等要求外,快速有效的设计方法可大大缩短其研发应用时间周期,利于技术迭代升级。本文基于传输线理论和逐级匹配技术,控制复合多层吸波材料界面的电磁传输特性,设计实现满足材料应用指标要求的复合多层吸波材料。本文方法基于单频点提出,适用于单频及宽带设计要求。通过对实验室制备的多层吸波材料进行测试,得到在目标单频点反射率-30 dB及目标频带内平均反射率-35 dB的实测结果,验证了本文提出方法的正确性和有效性。本方法有望成为快速有效研发复合多层吸波材料的有效手段之一。 相似文献
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Jiacheng Wang Changshu Xiang Qian Liu Yubai Pan Jingkun Guo 《Advanced functional materials》2008,18(19):2995-3002
A series of novel, dense, and interesting ordered mesoporous carbon (OMC)/fused silica composites with different carbon contents has been prepared by a controllable but simple sol‐gel method followed by hot‐pressing. In the as‐sintered OMC/fused silica composites the carbon particles still exist in the form of perfectly ordered carbon nanowires. Conductivity measurements on the composites indicate that these novel composites are electrically conductive and have a typical percolation threshold of 3.5–5 vol% OMC. The electromagnetic interference (EMI) shielding efficiency (SE) of an OMC/fused silica composite containing 10 vol% OMC is as high as 40 dB in the X band which is higher than that of a carbon nanotube (CNT)/ fused silica composite with the same carbon content (~30 dB). This indicates that these conductive OMC/fused silica composites are very suitable for an application as EMI shielding materials. Upon increasing the volume content of OMC in the composite the overall contribution as well as the increase rate of the microwave absorption are larger than those of the microwave reflection, which suggest that OMC/fused silica composites may also be promising electromagnetic (EM) wave absorbing materials. Based on the promising properties of these composites this work will hopefully lead to the development of new low‐cost and highly efficient EMI shielding or EM wave absorbing materials. 相似文献
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In this paper, we systematically report the preparation of carbon‐nanotube (CNT)‐reinforced Zr‐based bulk metallic glass (BMG) composites. The physical and mechanical properties of the composites were investigated. Compressive testing shows that the composites still display high fracture strength. Investigation also shows that the composites have strong ultrasonic attenuation characteristics and excellent wave absorption ability. The strong wave absorption implies that CNT‐reinforced Zr‐based BMG composites, besides their excellent mechanical properties, may also have significant potential for applications in shielding acoustic sound or environmental noise. 相似文献
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采用Bessel和Hankel函数级数模技术,对不同多壁碳纳米管在红外波段的电磁散射特性进行了研究.结果表明,不同半径、不同纳米管数目对入射的横磁波与横电波的散射现象产生不同的影响.在横磁波垂直入射时,不同结构多壁碳纳米管对其频率的选择性不明显,相同半径纳米管对横磁波的散射强度随纳米管数目的增加而增强,但其峰值不变;而在横电波入射时,不同结构多壁碳纳米管表现出强烈的频率选择性,其散射强度随半径、管数目的增加而明显增强.研究结果对利用碳纳米管进行红外波段的探测具有一定意义. 相似文献
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A. V. Solnyshkin I. L. Kislova A. N. Belov A. V. Sysa A. A. Stroganov V. I. Shevjakov M. V. Silibin A. A. Mihalchan A. A. Lysenko 《Semiconductors》2017,51(13):1702-1706
The results of a study of film composites based on polyvinylidene fluoride with carbon nanotubes (CNTs) by dielectric relaxation spectroscopy are presented. For composite samples containing more than 0.5 wt % of nanotubes, nonlinear current–voltage characteristics are obtained. The concentration dependences of the electrical conductivity of the composites are examined and the percolation threshold for the samples under study is determined. It is shown that an insignificant increase in the electrical conductivity of the composites is observed even upon filling with 0.2 wt % of CNTs, whereas the electrical conductivity becomes three orders of magnitude higher upon the introduction of 1 wt% of CNTs and is seven orders of magnitude higher at more than 3 wt %, compared with the unfilled polymer. This confirms that CNTs are promising for the development of electrically conducting composites and film materials on the basis of polyvinylidene fluoride. 相似文献
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综述了尖晶石型铁氧体/TiO2复合材料的水热法制备与性能研究进展,包括零维、一维结构的尖晶石型铁氧体/TiO2复合材料和特殊形貌的尖晶石型铁氧体/TiO2/石墨烯复合材料的水热法制备研究现状,以及复合材料电化学性能、光催化性能、吸波性能的研究进展。总结了二元或三元复合材料由于充分发挥了各组分材料间的协同作用以及复合材料具有的独特结构,使复合材料具有优异的电化学性能、光催化性能和吸波性能。指明未来应以水热法制备尖晶石型铁氧体/TiO2/石墨烯三元复合材料为目标,向着引入中空过渡层以及制备具有特殊结构的三元复合材料方向发展。 相似文献
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RaviPrakash Magisetty Anuj Shukla Balasubramanian Kandasubramanian 《Journal of Electronic Materials》2018,47(11):6335-6365
Functional radiation absorbent materials (RAMs) can transform incident microwave energy into heat energy, hence being essential to impede reflections of microwaves generated by modern radars in military, aerospace, and commercial applications. For such applications, use of composites is imperative to maintain an optimum bandwidth, enhance the magnetoelectric functional activity, ensure a flexible design, and reduce weight, which can be achieved by tuning the volume fractions of such materials. Use of ferrites is widely recommended for microwave (MW) suppression due to their appropriate magnetodielectric characteristics. This review first describes the requirements for an ideal MW absorber and accurate measurements for quantification of MW absorption. Then, the significance, applications, approaches, and experimental developments of magnetodielectric polymer composite RAMs are presented. Moreover, such composites facilitate exploration of nanoscale functional properties to achieve efficient RAMs. The permeability and permittivity at microwave frequencies, magnetic properties induced by unique elemental doping mechanisms, as well as physical and chemical properties of these composites are also presented. The resonance-dependent absorption condition for different families of magnetic ferrites, as well as the dependence of their magnetic properties on the resonant frequency and their absorption bandwidth (spinels up to 30 GHz, hexaferrites 1 GHz to 100 GHz), are presented for applications. Furthermore, magnetodielectric composites decorated with carbon fillers (carbon nanotubes/multiwall carbon nanotubes, graphene, reduced graphene oxide, etc.) with enhanced microwave absorption properties are discussed. Additionally, core–shell magnetodielectric materials are also discussed in detail. Finally, this review highlights the importance of magnetodielectric polymer composites decorated with conducting materials and core–shell magnetodielectric materials as effective broadband RAMs achieving the primary application requirement of broadband absorption of at least ?10 dB with reduced thickness. 相似文献
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基于短切碳纤维、碳纳米纤维、石墨烯及炭黑,分析研究碳基复合材料中吸收剂形状比对电磁特性,尤其是吸波性能的影响。采用矢量网络分析仪测试基于不同形状比吸收剂形成碳基复合材料的电磁参数,并且计算出样品理论反射损耗。结果发现,随着频率的增加,碳基复合材料的介电常数逐渐减小;碳纳米纤维样品厚度为2 mm,在8 GHz时反射损耗达到-8 d B;炭黑与石墨烯质量比为1∶1时,在0. 5~12. 8 GHz频段内损耗角正切tanδ随频率的增大而增大且样品厚度为2mm时,其在12~16. 2 GHz反射损耗小于-10 d B,且在12. 8 GHz时反射损耗达到-22. 5 d B。通过对不同形状比吸收剂形成碳基复合材料的电磁参数分析,发现具有一定长径比或较大比表面积的吸收剂复合有利于提升碳基复合材料的吸波性能。 相似文献