材料期刊网

Identification of the constituents of double-walled carbon nanotubes using Raman spectra taken with different laser-excitation energies

Journal of Materials Research

Double-walled carbon nanotubes (DWNTs), synthesized by the catalytic decomposition of methane, were explored by resonance Raman spectroscopy using different energies for laser excitation. Based on the radial breathing mode frequencies, the indices of the two layers of a DWNT were approximately assigned, depending on the interlayer separation of the two coaxial layers of the DWNT, which ranged from 0.34 to 0.40 nm. From the tentatively assigned results, it was found that the two walls of the DWNT are not strongly selected by chirality and diameter. The results, however, suggest that, for the tubes that are resonant with the available laser excitation energies, most of the outer layers of the observed DWNTs in our samples are semiconducting, while the inner layers of the observed DWNTs are either semiconducting or metallic based on the assembled DWNTs. The characteristics of the G, D, and G' band of the DWNTs are discussed, and a double peak feature in the D and G' band, originating from the inner and outer layers of the DWNTs, is reported.

关键词: scattering

基于空心球壳结构的吸波平板的吸波性能研究

李宝毅 , 段玉平 , 刘顺华

功能材料

对炭黑包覆发泡聚苯乙烯（EPS）颗粒的吸波性能进行了研究。讨论其吸波机理表明,谐振损耗和散射损耗对这种空心球壳结构的吸波体具有重要的意义。调节导电层厚度和球体半径可以控制吸波体的吸收强度和谐振频率。将其应用于水泥基吸波平板中发现它可以显著提高复合材料的吸波性能,特别是低频段的吸波性能,而且降低了材料密度。因此,炭包EPS颗粒是一种轻质高效的吸波填料,具有广泛的发展前景。

关键词: 空心球壳 , 吸波性能 , 谐振 , 散射