排序方式: 共有70条查询结果,搜索用时 15 毫秒
1.
2.
3.
4.
5.
采用密度泛函理论系统研究了超薄氧化物膜/金属体系FeO/Pt和FeO2/Pt及其表面不同区域(FCC,HCP和TOP)的几何结构、电子性质及氧的活性.研究发现,表面O-Fe高度差δz作为一个重要的特征结构参数直接影响局域表面静电势和表面氧的结合能: δz越大,静电势越大,氧的结合能越弱.计算发现,在FeO/Pt体系中,δz顺序为FCC > HCP > TOP,而FeO2/Pt中是FCC > TOP > HCP.此外,在FeO/Pt中,电荷转移方向是从氧化物膜到衬底,Fe的表观价态为+2.36,表面功函较纯Pt(111)的变化可忽略; 而FeO2/Pt中,电荷转移的方向是从衬底到氧化物,Fe的表观价态为+2.95,表面功函较纯Pt增加1.24 eV.进一步分析了电荷转移和表面偶极对电子性质的作用机制.这些研究结果对于认识超薄氧化物薄膜对表面几何结构、电子性质、表面氧活性的调制具有重要的启示意义. 相似文献
6.
电磁波导的半解析辛分析 总被引:18,自引:1,他引:18
根据电磁波导的Hamilton体系,辛几何可用于任意各向异性材料,而且便于处理不同区段的界面条件,横向的电场和磁场构成了对偶向量.基于Hamilton变分原理用半解析法进行横向离散应当保持体系的辛结构.离散后可以运用应用力学的有效算法,求解其辛本征值问题.每段波导可以引入两端Riccati矩阵,用精细积分法求解其方程组. 相似文献
7.
Richard A. Stern Richard W. Babbitt John Borowick Gerald Mikucki William Bayha 《International Journal of Infrared and Millimeter Waves》1985,6(10):999-1016
This paper describes the theoretical and experimental results of a novel leaky-wave antenna incorporating a homogeneous dielectric transmission line and radiating aperture into a single structure. The primary objective of this investigation is to demonstrate the ability to control aperture radiation by simply cutting slots into a metal-free dielectric transmission line. Experimental line source antennas with identical periodic slots were designed to operate in the 35 GHz frequency region. The successful performance of these antennas resulted in the design of a dielectric line source antenna with a symmetrical amplitude taper which provided a lower sidelobe level. The design represents a significant breakthrough in achieving affordable, low-loss, lightweight antennas in the millimeter wave region. The most significant applications for this type of antenna include radar surveillance and tactical missile-seeker terminal guidance. 相似文献
8.
9.
室内声场计算机仿真是近年来在声学领域颇受重视的研究方向。近来波导网络法、自适应声束跟踪法和神经网络法开始被引入,并逐渐受到重视。着重介绍这三种新方法的基本思想和优缺点。 相似文献
10.