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51.
Wei Shi Yujie J. Ding Changshui Fang Qiwei Pan Qingtian Gu 《Optics and Lasers in Engineering》2002,38(6):361-371
Mode-matching and effective index methods are used to analyze single-mode operation of optical rib polymer waveguides. Their single-mode waveguiding conditions are determined. Single-mode rib waveguides fabricated from guest–host polyetherketone are presented. The estimated propagation loss of straight rib-waveguides is 0.7 dB/cm at 1.55 μm. Furthermore, by using the mode field-transfer matrix method, 2×2 and 4×4 polymer Mach–Zehnder interference switch operating at 1.55 μm wavelength has been designed based on optical multi-mode interference. 相似文献
52.
We derive an explicit autocorrelation function (ACF) formula of state of polarization for a fiber transmission system with polarization mode dispersion (PMD) and polarization dependent loss (PDL), which is found to agree well with Monte Carlo simulation. Then we use the new ACF to investigate the combined effect of PMD and PDL on the polarization multiplexed scheme. We find the performance of the polarization multiplexed scheme can be deteriorated more severely than the case without PDL. 相似文献
53.
The crystal structure, magnetic and magnetotransport properties of the variation of B′-site transition metal in Sr2FeMO6 (M=Mo, W) with double perovskites structure have been investigated systematically. Measurements of magnetization vs. temperature at H=5 T show that Sr2FeMoO6 is a ferromagnet and Sr2FeWO6 is an antiferromagnet with TN∼35 K. Additionally, the large magnetoresistance ratio (MR) of ∼22% (H=3 T) at room temperature (RT) was observed in the Sr2FeWO6 compound. However, the Sr2FeMoO6 compound did not show any significant MR even at high fields and RT (MR∼1%; H=3 T and 300 K). The implications of these findings are supported by band structure calculations to explain the interaction between the 4d(Mo) and 5d(W) orbitals of transition metal ions and oxygen ions. 相似文献
54.
Kunyu Guo 《Journal of Functional Analysis》2004,213(2):380-411
This paper mainly concerns defect operators and defect functions of Hardy submodules, Bergman submodules over the unit ball, and Hardy submodules over the polydisk. The defect operator (function) carries key information about operator theory (function theory) and structure of analytic submodules. The problem when a submodule has finite defect is attacked for both Hardy submodules and Bergman submodules. Our interest will be in submodules generated by polynomials. The reason for choosing such submodules is to understand the interaction of operator theory, function theory and algebraic geometry. 相似文献
55.
根据Co P非晶态合金结构的短程有序和结构中可能存在P -P相互作用的实验事实 ,选择了单磷原子簇模型ConP(n =1~ 5 )和双磷原子簇模型ConP2 (n =1~ 4 ) ,用密度泛函理论方法对其进行计算 .结果表明 ,在单磷Co2 P( 2 ) 、Co3 P( 1) 及Co4P( 2 ) 模型体系中 ,Co原子供给P原子电子 ,与电负性规则一致 ,同时Co和P之间具较强化学作用 ,可以形成稳定的原子簇 ;而在双磷和单磷原子簇Co5P( 1) 模型体系中 ,形成的原子簇不稳定 ,采用单磷Co2 P( 2 ) 、Co3 P( 1) 及Co4P( 2 ) 模型能较好地反映Co P非晶态合金的结构特点 . 相似文献
56.
This paper undertakes a systematic treatment of the low regularity local wellposedness and ill-posedness theory in Hs andHs for semilinear wave equations with polynomial nonlinearity in u and (e)u. This ill-posed result concerns the focusing type equations with nonlinearity on u and (e)tu. 相似文献
57.
58.
TANG Chen ZHANG Fang YAN Hai-Qing CHEN Zhan-Qing LUO Tao 《理论物理通讯》2005,44(3):435-439
We develop the three-step explicit and implicit schemes of exponential fitting methods. We use the three- step explicit exponential fitting scheme to predict an approximation, then use the three-step implicit exponential fitting scheme to correct this prediction. This combination is called the three-step predictor-corrector of exponential fitting method. The three-step predictor-corrector of exponential fitting method is applied to numerically compute the coupled nonlinear Schroedinger equation and the nonlinear Schroedinger equation with varying coefficients. The numerical results show that the scheme is highly accurate. 相似文献
59.
Song LI Guo Mao WANG Zhi Song LIU 《数学学报(英文版)》2005,21(6):1475-1486
The purpose of this paper is to investigate the mean size formula of wavelet packets in Lp for 0 〈 p ≤ ∞. We generalize a mean size formula of wavelet packets given in terms of the p-norm joint spectral radius and we also give some asymptotic formulas for the Lp-norm or quasi-norm on the subdivision trees. All results will be given in the general setting, 相似文献
60.
线性泛函方程解的振动性的新结果 总被引:1,自引:0,他引:1
本文研究高阶泛函方程x(g(t))=P(t)x(t)+Q1(t)x(g2(t))+…+Qk(t)x(gk+1(t))解的振动性,得到了一些新的振动条件.改进和推广了已有结果. 相似文献