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101.
The stability and local vibrational mode (LVM) of hydrogen related p-type AlN have been studied by first-principles calculations based on density functional theory. The stable and metastable microscopic geometries ofgroup-Ⅱ (Be, Mg, Ca, Sr, Ba)-H complexes have been investigated. The calculated results indicate that BCⅡ is the most stable configuration for isolated interstitial H+ and Be-H complexes, while it is ABN,⊥ for Mg-H, Ca-H, Sr-H and BaH complexes. Moreover, the vibrational frequencies and the values ofk and |α| for the H atom with LVM are calculated. Here, the values of k and |α| are used to describe the parameters of the harmonic and anharmonic contributions, re-spectively. The calculated results indicate that the larger the size of the doped ion is, the shorter the N-H bond length is, and the larger the potential energy, the vibrational frequencies, the values of k and |α| are. This implies that the size of the doped ion has an important influence on the vibrational properties of H. 相似文献
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针对当前高校工程训练教学管理系统页面风格杂乱以及后期维护不便的问题,提出运用最新的Evolutility4.0在原有的基础上对高校工程训练教学管理系统进行优化,使系统能够达到页面简洁统一、操作方便的效果,同时减少后期维护的不便。 相似文献
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曾青云 《南方冶金学院学报》1992,13(4):317-322
介绍了几种在IBM—PC机上采用西文BASIC而无需中文磁盘操作系统支持下,在屏幕上绘制科技图形时如何显示中文字符简单而实用的方法。 相似文献
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郭庆云 《石油化工腐蚀与防护》2002,19(3):59-61
该漏水检测技术采用听音杆、检漏仪和相关仪对地埋供水管道进行泄漏探测 ,最大测试距离可达5 0 0m ,可对泄漏点进行精确定位。文中详细论述了仪器的使用方法和应注意的问题 ,并列举了检测实例 相似文献
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In this paper, we propose a rapid code acquisition scheme for direct-sequence spread-spectrum (DS/SS) system basing on the improved seed accumulation of sequential estimation (ISASE). This method solves the problem that SASE scheme cannot work in the presence of carrier-frequency offset. The mean acquisition time of the ISASE scheme is derived by the generating function flow graph technique, and the tolerance of carrier-frequency offset is obtained in a closed-form expression. The performance of the proposed acquisition scheme is analytically evaluated in terms of the mean acquisition time. Analysis in theory and numerical results show that the proposed scheme yields improvement of the mean acquisition time over the RASE scheme by a factor of 2–15 times for the PN} period more than 255 in normal operating condition. For the important parameter-accumulating number m, we recommend to choose from 5 to 20 through the tradeoff of the tolerance of carrier-frequency offset and acquisition speed.
Jiachi Wang was born in September, 1971. He is a Phd candidate in department Electronics and Information Engineering, Huazhong University of Science and Technology. His research areas include spread spectrum and digital communication, and digital signal processing.
Xiulin Hu was born in 1945. He is a professor and Phd advisor in department Electronics and Information Engineering, Huazhong University of Science and Technology. His research areas include spread spectrum and digital communication.
Yunyu Zhang was born in 1948. She is a professor in department Electronics and Information Engineering, Huazhong University of Science and Technology. Her research areas include software radio and digital communication.
Qingyun Dai was born in 1977. She is a Phd candidate in department of Electronics and Information Engineering, Huazhong University of Science and Technology. Her research areas is wireless network. 相似文献