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基于简单紧束缚方法理论,利用一维碳纳米管的量子化周期边界条件得到了碳纳米管的电子能级结构关系.并结合已报道的碳纳米管中电子与声子相互作用的实验结果,得到了碳纳米管能够辐射太赫兹波的结论.通过数值结果验证了碳纳米管在外场作用下能够产生太赫兹波,并对数值计算结果中太赫兹波的振荡现象给予合理的解释.其结果为进行碳纳米管产生太赫兹辐射的实验研究提供深入的理论基础.
关键词:
太赫兹波
碳纳米管 相似文献
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Numerical modelling on the transient electromagnetic scattering by a two-dimensional (21)) cylinder located on a time-evolving rough surface is presented by using time-domain integral equations. The proposed special choice of a tapered Gauss pulse incident wave removes the truncation error from the rough surface. Additionally, a two-level averaging technique is utilized to overcome the instability from the time marching procedure of solving integral equations. Excellent correspondences between the surface current distributions, as well as the far-zone fields, computed by the proposed method and that obtained by the traditional method of moments associated with the inverse discrete Fourier transformation scheme demonstrate the accuracy of the modelling. 相似文献
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An analytical solution is presented for the electromagnetic scattering from an infinite-length metallic carbon nanotube and a carbon nanotube bundle.The scattering field and scattering cross section are predicted using a modal technique based on a Bessel and Hankel function for the electric line source and a quantum conductance function for the carbon nanotube.For the particular case of an isolated armchair (10,10) carbon nanotube,the scattered field predicted from this technique is in excellent agreement with the measured result.Furthermore,the analysis indicates that the scattering pattern of an isolated carbon nanotube differs from that of the carbon nanotube bundle of identical index (m,n) metallic carbon nanotubes. 相似文献
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Characterization of the radiation from single-walled zig-zag carbon nanotubes at terahertz range 下载免费PDF全文
This paper investigates the radiation characteristics of
metal single-walled zig-zag carbon nanotubes as a dipole antenna at
terahertz wave range. The current distribution, input impedance and
mutual impedance are calculated for various geometrical parameters
of vertically-aligned carbon nanotubes. The numerical results
demonstrate the properties of the antenna depending strongly on the
geometrical parameters such as the radius, the lengths of carbon
nantobues, and the spacing between nanotubes. It is found that the
zig-zag carbon nanotubes exhibit very high input impedance and the
mutual impedances for antenna array applications. These unique high
impedance properties are different from the conventional metal thin
wire antenna. The far-field patterns and gain of antenna array are
also calculated. The maximum gain of array of 100-element array is
up to 20.0~dB, which is larger than the gain of 0.598~dB of single
dipole antenna at distance d = 0.5\lambda . 相似文献
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An analytical solution is presented for the electromagnetic scattering from an infinite-length metallic carbon nanotube and a carbon nanotube bundle. The scattering field and scattering cross section are predicted using a modal technique based on a Bessel and Hankel function for the electric line source and a quantum conductance function for the carbon nanotube. For the particular case of an isolated armchair (10, 10) carbon nanotube, the scattered field predicted from this technique is in excellent agreement with the measured result. Furthermore, the analysis indicates that the scattering pattern of an isolated carbon nanotube differs from that of the carbon nanotube bundle of identical index (m, n) metallic carbon nanotubes. 相似文献
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研究了线电流源平行放置在无耗异向介质层覆盖的无限长导体圆柱附近模型的电磁特性.首先,给出了电磁模型描述,求出此电磁模型的精确解.其次,利用精确解进行数值计算,得到几何参数和电磁参数不同情况下电磁模型的近场图形,并通过方向性系数和归一化辐射阻抗研究其远场特性.利用异向介质的负折射特性,在异向介质层的近场图形内得到明显的“焦点”,这个焦点在普通介质层中是不存在的.该电磁模型同前人方法进行了比较,验证了本电磁模型的有效性.
关键词:
线电流源
异向介质
方向性系数
辐射阻抗 相似文献