The advantages of Fe,Ni metals and one-dimensional(1D)carbon materials are combined in this study using a simple method to prepare FeNi/C nanofibers for electromagnetic microwave(EM)absorption.The prepared FeNi/C nano...The advantages of Fe,Ni metals and one-dimensional(1D)carbon materials are combined in this study using a simple method to prepare FeNi/C nanofibers for electromagnetic microwave(EM)absorption.The prepared FeNi/C nanofibers exhibit excellent EM absorption performance under dielectric/magnetic synergistic effect.At a frequency of 13.3 GHz,the minimum reflection loss(RLmin)reaches-57.15 dB,and effective absorption bandwidth(EAB)is as high as 4.0 GHz(12.5-16.5 GHz),with a thickness and filling rate of only 1.6 mm and 30 wt.%,respectively.Analysis shows that the EM absorption performance of FeNi/C nanofibers far exceeds that of single-component nanofibers and pure carbon fibers,and the excellent EM absorption performance is due to its unique microstructure and excellent electromagnetic properties.The FeNi alloy loaded on carbon nanofibers forms rich heterogeneous interfaces,and the three-dimensional(3D)conductive network composed of 1D carbon fibers increases the migration path of electrons.In addition,FeNi alloy,as an impedance regulation factor,strengthens the dielectricity of the carbon matrix while providing multidimensional magnetism,achieving impedance matching.This work is thought to contribute to the promotion of emerging absorbers by providing a novel strategy for the development of new 1D magnetic carbon-based high-performance EM absorbing materials.展开更多
Tetraamido-oxacalix[4]arene derivatives have been synthesized via the reactions of tetraamino-oxacalix[4]arene with excess butyryl chloride, octanoyl chloride, benzoyl chloride and p-toluenesulfonyl chloride, respecti...Tetraamido-oxacalix[4]arene derivatives have been synthesized via the reactions of tetraamino-oxacalix[4]arene with excess butyryl chloride, octanoyl chloride, benzoyl chloride and p-toluenesulfonyl chloride, respectively. JH NMR results suggest that these oxacalix[4]arene derivatives preferentially adopt the 1,3-alternate （saddle-like） con- formation in solution, which were also the case in the solid state as demonstrated by single crystal X-ray analysis. A dimerized slipped capsule could be formed by tetra-butyramido-oxacalix[4]arene in the solid state via intermolecu- lar hydrogen bond interactions under the assistance of two encapsulated methanol molecules. On the other hand, a molecular cavity was formed by tetra-p-toluenesulfonamido-oxacalix[4]arene which can encapsulate a solvent molecule of ethyl acetate.展开更多
基金supported by the Natural Science Foundation of Shandong Province(Nos.ZR2021ME019 and ZR2019BB063).
文摘The advantages of Fe,Ni metals and one-dimensional(1D)carbon materials are combined in this study using a simple method to prepare FeNi/C nanofibers for electromagnetic microwave(EM)absorption.The prepared FeNi/C nanofibers exhibit excellent EM absorption performance under dielectric/magnetic synergistic effect.At a frequency of 13.3 GHz,the minimum reflection loss(RLmin)reaches-57.15 dB,and effective absorption bandwidth(EAB)is as high as 4.0 GHz(12.5-16.5 GHz),with a thickness and filling rate of only 1.6 mm and 30 wt.%,respectively.Analysis shows that the EM absorption performance of FeNi/C nanofibers far exceeds that of single-component nanofibers and pure carbon fibers,and the excellent EM absorption performance is due to its unique microstructure and excellent electromagnetic properties.The FeNi alloy loaded on carbon nanofibers forms rich heterogeneous interfaces,and the three-dimensional(3D)conductive network composed of 1D carbon fibers increases the migration path of electrons.In addition,FeNi alloy,as an impedance regulation factor,strengthens the dielectricity of the carbon matrix while providing multidimensional magnetism,achieving impedance matching.This work is thought to contribute to the promotion of emerging absorbers by providing a novel strategy for the development of new 1D magnetic carbon-based high-performance EM absorbing materials.
基金Financial support from National Natural Science Foundation of China，Shanghai Commission for Science and Technology，"Strategic Priority Research Program" of the Chinese Academy of Sciences (No.XDA01020304) is acknowledged
文摘Tetraamido-oxacalix[4]arene derivatives have been synthesized via the reactions of tetraamino-oxacalix[4]arene with excess butyryl chloride, octanoyl chloride, benzoyl chloride and p-toluenesulfonyl chloride, respectively. JH NMR results suggest that these oxacalix[4]arene derivatives preferentially adopt the 1,3-alternate （saddle-like） con- formation in solution, which were also the case in the solid state as demonstrated by single crystal X-ray analysis. A dimerized slipped capsule could be formed by tetra-butyramido-oxacalix[4]arene in the solid state via intermolecu- lar hydrogen bond interactions under the assistance of two encapsulated methanol molecules. On the other hand, a molecular cavity was formed by tetra-p-toluenesulfonamido-oxacalix[4]arene which can encapsulate a solvent molecule of ethyl acetate.
