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171.
GuangGuiDING 《数学学报(英文版)》2003,19(4):793-800
In this paper,we study the extension of isometries between the unit spheres of some Banach spaces E and the spaces C(Ω). We obtain that if the set sm.S1(E) of all smooth points of the unit sphere S1(E) is dense in S1(E),then under some condition,every surjective isometry V0 from S1(E) onto S1(C(Ω)) can be extended to be a real linearly isometric map V of E onto C(Ω).From this resultwe also obtain some corollaries. This is the first time we study this problem on different typical spaces,and the method of proof is also very different too. 相似文献
172.
S. É. Ivanova A. M. Tkachuk M.-F. Joubert Y. Guiout S. Gui 《Optics and Spectroscopy》2000,89(4):535-548
Nd3+:Na0.4Y0.6F2.2 (Nd3+:NYF) crystals are grown by the Stockbarger–Bridgman method for a stoichiometric mixture prepared by the solid-phase method and containing neodymium up to 20 at. %. The absorption spectrum of Nd3+:NYF crystals exhibits bands located in the emission region of laser diodes. The peak absorption cross section of the 796.8-nm band is σ a = 0.96 × 10–20 cm2 and the bandwidth is Δλ = 17.5 nm. The most intense luminescence band is located at 1.05 μ m and the radiative time of the 4F3/2 level is τ0 = τexp ~ 960 μ s. It is shown that the 2P3/2 and 4D3/2 levels of Nd3+:NYF crystals are also radiative with lifetimes τ exp equal to ~110 and 9.5 μ s, respectively. However, these radiative transitions are partially quenched due to nonradiative relaxation. The intensity parameters Ω t are determined by the Judd–Ofelt method to be Ω2 = 1.18 × 10–20, Ω4 = 1.55 × 10–20, and Ω 6 = 2.85 × 10–20 cm 2. Using these parameters, the probabilities of radiative transitions and branching ratios are calculated, and the probabilities of nonradiative transitions are estimated. A conclusion is made that Nd3+:NYF crystals are promising as active media for diode-pumped tunable lasers, in particular, up-conversion-pumped lasers. 相似文献
173.
采用微扰静态(PSS)模型近似处理极化和结合能效应,并引入了相对论效应、能量损失效应和库仑偏转效应修正的ECPSSR理论是描述直接库仑电离过程最成功的理论,但对于低能离子入射时, 其结果明显低于实验值. 采用联合分离原子(USA)模型替代ECPSSR中的PSS模型,考虑分子轨道效应得到了基于USA模型的电离理论——MECUSAR理论. 对部分碰撞系统进行了计算,得到的碰撞截面与实验结果基本符合. 结合OBKN(Oppenheimer-Brinkman-Kramers formulas of Nikolae
关键词:
X射线产生截面
离子-原子碰撞
电子俘获 相似文献
174.
In this paper, we evaluated the quasinormal modes of electromagnetic perturbation in a Schwarzschild black hole surrounded
by the static spherically symmetric quintessence by using the third-order WKB approximation when the quintessential state
parameter w
q
in the range of −1/3 < w
q
< 0. Due to the presence of quintessence, Maxwell field damps more slowly. And when at −1 < w
q
< −1/3, it is similar to the black hole solution in the ds/Ads spacetime. The appropriate boundary conditions need to be
modified. 相似文献
175.
研究了基于InP基的In0.65Ga0.35As/In0.52Al0.48As赝型高迁移率晶体管材料中纵向磁电阻的Shubnikov-deHaas(SdH)振荡效应和霍耳效应,通过对纵向磁电阻SdH振荡的快速傅里叶变换分析,获得了各子带电子的浓度,并因此求得了各子带能级相对于费米能级的位置.联立求解Schrdinger方程和Poisson方程,自洽计算了样品的导带形状、载流子浓度分布以及各子带能级和费米能级位置.理论计算和实验结果很好符合.实验和理论计算均表明,势垒层的掺杂电子几乎全部转移到了量子阱中,转移率在95%以上. 相似文献
176.
The Josephson effect of Bose condensates with a weak link created by superposing a far-off-resonant red-detuned laser beam on a double-well potential is theoretically considered. The numerical simulations show that there would be c/ear Josephson effect for this sort of three-well system. The present work gives a feasible scheme to study a new type of weak link which is crucial to investigate experimentally the Josephson effect. 相似文献
177.
We propose a simple scheme to generate an arbitrary photon-added coherent state of a travelling optical field by combining an array of degenerate parametric amplifiers and corresponding single-photon detectors. Particularly, when the single-photon-added coherent state is observed by developing the novel technique of Zavatta et al (2004 Science 306 660), we can simultar/eously obtain the generalized N-qubit W state. 相似文献
178.
Guofu Qiu Gui Yu Yunqi Liu Cheng Ye Jingui Qin Zhen Li 《Journal of polymer science. Part A, Polymer chemistry》2011,49(9):1977-1987
In this article, according to the concept of “suitable isolation group,” six new AB2‐type polytriazoles containing azo‐chromophore moieties, derived from the same hyperbranched polymer intermediate, were successfully prepared through click reaction under copper(I) catalysis by modifying the synthetic route, in which different isolation groups in different size were introduced to the periphery of the hyperbranched polymers as end‐capping moieties. With the different end‐capping groups, these hyperbranched polymers, P1 – P6 , exhibited different solubility and processability; also, their nonlinear optical properties were modified accordingly, realizing the adjustment of the properties of hyperbranched polymers through the structural design. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011 相似文献
179.
180.
A magnetically stabilized fluidized bed (MSFB, φ 500mm x 2100mm) was designed to study dust removal from flue gas. Based on the mechanism of dust removal in a fixed bed, the effects on collection efficiency of magnetic field intensity, ratio of flue gas velocity to minimum fluidization velocity, bed height, and particle average diameter, were investigated. Then feasible methods for MSFB to better remove dust were proposed. Over 95% of dust removal with MSFB can be achieved, when stable fluidization is maintained and when magnetic particles are frequently renewed. 相似文献