Within the framework of the dielectric continuum model and Loudon ＇s uniaxial crystal model, the properties of frequency dispersion of the propagating （PR） optical phonon modes and the coupling functions of electro...Within the framework of the dielectric continuum model and Loudon ＇s uniaxial crystal model, the properties of frequency dispersion of the propagating （PR） optical phonon modes and the coupling functions of electron-PR phonons interaction in an asymmetrical wurtzite quantum well （QW） are deduced and analyzed via the method of electrostatic potential expanding. Numerical calculation on an asymmetrical Alo.25Gao.75N/GaN/Alo.15Gao.ssN wurtzite QW were performed. The results reveal that there are infinite branches of PR phonon modes in the systems. The behaviors of frequency forbidden of PR modes in the asymmetric QWs have been clearly observed. The mathematical and physical origins for these features have been analyzed in depth. The PR optical phonon branches have been distinguished and labelled reasonably in terms of the oscillating properties of the PR modes in the well-layer material. Moreover, the amplitudes and frequency properties of the electron-PR modes coupling functions in the barrier and well materials have also been analyzed from both of the mathematical and physical viewpoints.展开更多
This paper examines the US public diplomacy toward China in the post-9/11 era. Although emphasizing more on promoting a positive American image in the Arabic world, the Bush administration also stepped up its pace on ...This paper examines the US public diplomacy toward China in the post-9/11 era. Although emphasizing more on promoting a positive American image in the Arabic world, the Bush administration also stepped up its pace on beaming the American message to China. Analyzing the public diplomatic behavior since 9/11, including the President＇s visit to the Olympics, the public diplomacy ambassador sent to China, the influence of the VOA, and the privatization of pubhc diplomacy, the author evaluates the effectiveness of the US public diplomacy toward China, which becomes more pragmatic than ideological. In the end, the divide of the American image in China illustrates the complexity of the US public diplomacy in China.展开更多
基金The project supported by the Science and Technology Project of Adwnced Academy of Guangzhou City under Grant No. 2060, National Natural Science Foundation of China under Grant Nos. 60276004 and 60390073, and the Scientific Research Foundation for the Returned 0verseas Chinese Scholars of the Ministry of Education of China
文摘Within the framework of the dielectric continuum model and Loudon ＇s uniaxial crystal model, the properties of frequency dispersion of the propagating （PR） optical phonon modes and the coupling functions of electron-PR phonons interaction in an asymmetrical wurtzite quantum well （QW） are deduced and analyzed via the method of electrostatic potential expanding. Numerical calculation on an asymmetrical Alo.25Gao.75N/GaN/Alo.15Gao.ssN wurtzite QW were performed. The results reveal that there are infinite branches of PR phonon modes in the systems. The behaviors of frequency forbidden of PR modes in the asymmetric QWs have been clearly observed. The mathematical and physical origins for these features have been analyzed in depth. The PR optical phonon branches have been distinguished and labelled reasonably in terms of the oscillating properties of the PR modes in the well-layer material. Moreover, the amplitudes and frequency properties of the electron-PR modes coupling functions in the barrier and well materials have also been analyzed from both of the mathematical and physical viewpoints.
文摘This paper examines the US public diplomacy toward China in the post-9/11 era. Although emphasizing more on promoting a positive American image in the Arabic world, the Bush administration also stepped up its pace on beaming the American message to China. Analyzing the public diplomatic behavior since 9/11, including the President＇s visit to the Olympics, the public diplomacy ambassador sent to China, the influence of the VOA, and the privatization of pubhc diplomacy, the author evaluates the effectiveness of the US public diplomacy toward China, which becomes more pragmatic than ideological. In the end, the divide of the American image in China illustrates the complexity of the US public diplomacy in China.
