65 resultados para 738
Resumo:
Recognizing the computational difficulty due to the exponential behavior of the evanescent states in the calculations of the electron transmission in waveguide structures, the authors propose two transfer matrix methods and apply them to investigate the influence of the evanescent states on the electron wave propagation. The study shows that the effect of the evanescent states on the electron transport is obvious when the electron energy is close to the subband minima. The results show that the calculated transmissions are much enhanced if the evanescent states are omitted in the calculations. For the multiple-stub structures, it is found that the connecting channel length has a critical effect on the electron transmission depending on it larger or smaller than the attenuation lengths of evanescent states. Based on the study of the evanescent states, a new kind of waveguide structures which exhibit quantum modulated transistor action is proposed. (C) 1997 American Institute of Physics.
Resumo:
国家自然科学基金
Resumo:
其它基金
Study on the iron–silica interaction of a co-precipitated Fe/SiO2 Fischer–Tropsch synthesis catalyst
Resumo:
IEECAS SKLLQG
Resumo:
生态旅游可以简单地定义为发生在那些具有独特的风景、特殊的生态学价值和具有纯粹自然性的受保护区域的旅游活动,也可以被理解为广义旅游的一部分,即可为自然和文化资源保护提供经济支持的一种旅游。根据生态旅游协会的定义(1991),生态旅游是一种前往自然区域以...