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Xiangdong Liu Hongwei Liu Kexu Yuan Huiping Du 《International Journal of Infrared and Millimeter Waves》1991,12(9):1023-1034
According to the angular-spectrum method, a radiation beam of an antenna horn in the Fresnal region is decomposed into the plane waves with the fast Fourier transform algorithm and the waves diffracted from a reflection grating are superposed as a diffracted beam. Compared with the reflected beam from the same size mirror, the radiation half width of the diffracted beam from a grating is narrower and its lateral shape is shift. These performances have been experimentally verified at Ka-band by: (1). The relative diffraction efficiencies in the first order with two triangular gratings which is put along propagating direction of a beam produced by a conical lens-horn. (2). H-plane lateral width with power—3dB lapsed of the focus beam from a grating and a mirror in a grating spectrometer for millimeter waves (25–100 GHz). 相似文献
24.
The IR finite one-loop box scalar integral with massless internal lines has been recalculated. The result is very compact,
simple and valid for arbitrary values of the relevant kinematic variables. It is given in terms of only two dilogarithms and
a few logarithms, all of very simple arguments.
Received: 31 January 2002 / Published online: 26 April 2002 相似文献
25.
Hongwei Yu 《General Relativity and Gravitation》1991,23(3):297-304
By solving the coupled SU(5) Einstein-Yang-Mills-Higgs equations, we obtain the exact Reissner-Nordstrom type gravitational field of a family of spherically symmetric SU(5) dyons with magnetic charge 1/2e. 相似文献
26.
Wang Yongqian Liao Xianbo Diao Hongwei Cheng Wenchao Li Guohua Chen Changyong Zhang Shibin Xu Yanyue Chen Weide Kong Guanglin 《中国科学A辑(英文版)》2002,45(10):1320-1328
A set of a-SiOx:H (0.52 <x< 1.58) films are fabricated by plasma-enhanced-chemical-vapor-deposition (PECVD) method at the substrate temperature
of 250°C. The microstructure and local bonding configurations of the films are investigated in detail using micro-Raman scattering,
X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR). It is found that the films are
structural inhomogeneous, with five phases of Si, Si2O:H, SiO:H, Si2O3:H and SiO2 that coexist. The phase of Si is composed of nonhydrogenated amorphous silicon (a-Si) clusters that are spatially isolated.
The average size of the clusters decreases with the increasing oxygen concentration x in the films. The results indicate that
the structure of the present films can be described by a multi-shell model, which suggests that a-Si cluster is surrounded
in turn by the subshells of Si2O:H, SiO:H, Si2O3:H, and SiO2. 相似文献
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郑州工程学院数理系 《数学物理学报(A辑)》2004,24(3):329-336
该文考虑一类新的非线性方程(|ut|r-2ut)t-Δutt-Δu-ρ(t)Δut=f(u) 的初边值问题,利用小扰动法证明了整体弱解的
存在性,借用位势井的概念得到了解的稳定性.〖HT5”H〗关键词:〖HT5”SS〗非线性发展方程;初边值问题;整体弱解;稳定性. 相似文献
29.
Suppose that the signal X to be estimated is a diffusion process in a random medium W and the signal is correlated with the observation noise. We study the historical filtering problem concerned with estimating the signal path up until the current time based upon the back observations. Using Dirichlet form theory, we introduce a filtering model for general rough signal X
W
and establish a multiple Wiener integrals representation for the unnormalized pathspace filtering process. Then, we construct a precise nonlinear filtering model for the process X itself and give the corresponding Wiener chaos decomposition. 相似文献
30.
取代对苯二酚醚化物的合成研究 总被引:2,自引:0,他引:2
本文从取代的对苯三酚3出发、利用Williamson醚化反应合成了一系列它的醚化产物4a-4H,给出了它们的核磁共振数据(氢谱和碳谱)。讨论了影响醚化反应的一些因素,比较了不同烷化剂发生醚化反应的活泼性。 相似文献