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Effect of chemical vapor infiltration treatment on the wave-absorbing performance of carbon fiber/cement composites 被引量:4
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作者 Kezhi Li Chuang Wang Hejun Li Lingjun Guo Jihua Lu 《Journal of University of Science and Technology Beijing》 CSCD 2008年第6期808-815,共8页
Short carbon fibers were treated at high temperatures around 1100℃ through chemical vapor infiltration technology. A thinner layer ofpyrocarbon was deposited on the fiber surface. The dispersion of carbon fibers in a... Short carbon fibers were treated at high temperatures around 1100℃ through chemical vapor infiltration technology. A thinner layer ofpyrocarbon was deposited on the fiber surface. The dispersion of carbon fibers in a cement matrix and the mechanical properties of carbon fiber/cement composites were investigated by scanning electron microscopy (SEM) and other tests. The reflec- tivity of electromagnetic waves by the composites was measured in the frequency range of 8.0-18 GHz for different carbon fiber contents of 0.2wt%, 0.4wt%, 0.6wt%, and 1.0wt%. The results show that the reflectivity tends to increase with the increase of fiber content above 0.4wt%. The minimum reflectivity is -19.3 dB and the composites exhibit wave-absorbing performances. After pyrocarbon is deposited on the fiber, all the refiectivity data are far greater. They are all above -10 dB and display mainly wave-reflecting performances. 展开更多
关键词 carbon fibers chemical vapor infiltration CEMENT REFLECTIVITY wave-absorbing property
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Wave-absorbing Properties of a Cement-based Coating with MnO2/Activated Carbon Composite
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作者 刘润清 SUN Sihui +1 位作者 YANG Yunquan CHI Jun 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2018年第2期394-402,共9页
MnO_2/activated carbon composite(Mn-ACC) wave absorber was prepared by the reaction between Mn(CH_3COO)_2 and KMnO_4 on activated carbon. Then, a novel cement based composite absorbing coating(CB-CAC) was prepar... MnO_2/activated carbon composite(Mn-ACC) wave absorber was prepared by the reaction between Mn(CH_3COO)_2 and KMnO_4 on activated carbon. Then, a novel cement based composite absorbing coating(CB-CAC) was prepared by adding the Mn-ACC, manganese zinc ferrite and rubber particles into cement. XRD method was used to analyze the reaction products of the Mn-ACC. The tensile bond strength and the wave absorbing properties of the CB-CACs were also tested. The results showed that the crystallinity of MnO_2 formed in the Mn-ACC was poor. Adding Mn-ACC into the CB-CAC led to first increase and then decrease of the tensile bond strength. The tensile bond strength reached 1.89 MPa with 8.51% of the Mn-ACC. The CB-CACs obtained the optimal absorbing properties with the cement, manganese zinc ferrite, Mn-ACC, rubber particles and H_2O mass ratio of 7.5?7.5?1?1?5.5, respectively. The band width of the reflection below-10 dB was up to 8.8 GHz, which accounted for 57.14% of the test band. 展开更多
关键词 wave-absorbing coating wave-absorbing properties reflection
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Ultrahigh Density of Atomic CoFe-Electron Synergy in Noncontinuous Carbon Matrix for Highly Efficient Magnetic Wave Adsorption 被引量:7
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作者 Wenhuan Huang Qiang Qiu +5 位作者 Xiufang Yang Shouwei Zuo Jianan Bai Huabin Zhang Ke Pei Renchao Che 《Nano-Micro Letters》 SCIE EI CAS CSCD 2022年第6期192-205,共14页
Improving the atom utilization of metals and clarifying the M–M’interaction is both greatly significant in assembling high-performance ultra-light electromagnetic wave-absorbing materials.Herein,a high-temperature e... Improving the atom utilization of metals and clarifying the M–M’interaction is both greatly significant in assembling high-performance ultra-light electromagnetic wave-absorbing materials.Herein,a high-temperature explosion strategy has been successfully applied to assemble the hierarchical porous carbon sponge with Co–Fe decoration via the pyrolysis of the energetic metal organic framework.The as-constructed hybrid displays a superior reflection loss(RL)value of-57.7 d B and a specific RL value of-192 d B mg-1 mm-1 at 12.08 GHz with a layer thickness of 2.0 mm(loading of 15 wt%).The off-axis electron hologram characterizes the highly distributed numerous polarized nanodomain variable capacitors,demonstrating the dipole and interfacial polarization along the edges of the nanopores.More importantly,the X-ray absorption spectroscopy analysis verifies the mutual interaction between the metal cluster and carbon matrix and the electronic coupling responsible for the greatly improved electromagnetic wave absorption. 展开更多
关键词 Electromagnetic wave-absorbing materials Off-axis electron hologram M-M’interaction Hierarchical porous structure Energetic metal organic framework
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Green-Naghdi Theory,Part A:Green-Naghdi(GN) Equations for Shallow Water Waves 被引量:3
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作者 William C. Webster Wenyang Duan Binbin Zhao 《Journal of Marine Science and Application》 2011年第3期253-258,共6页
In this work, Green-Naghdi (GN) equations with general weight functions were derived in a simple way. A wave-absorbing beach was also considered in the general GN equations. A numerical solution for a level higher t... In this work, Green-Naghdi (GN) equations with general weight functions were derived in a simple way. A wave-absorbing beach was also considered in the general GN equations. A numerical solution for a level higher than 4 was not feasible in the past with the original GN equations. The GN equations for shallow water waves were simplified here, which make the application of high level (higher than 4) equations feasible. The linear dispersion relationships of the first seven levels were presented. The accuracy of dispersion relationships increased as the level increased. Level 7 GN equations are capable of simulating waves out to wave number times depth kd 〈 26. Numerical simulation of nonlinear water waves was performed by use of Level 5 and 7 GN equations, which will be presented in the next paper. 展开更多
关键词 Green-Naghdi (GN) equations dispersion relation wave-absorbing beach shallow-water waves
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