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101.
A. López-Ortega 《General Relativity and Gravitation》2006,38(12):1747-1770
Using the monodromy method we calculate the asymptotic quasinormal frequencies of an electromagnetic field moving in D-dimensional Schwarzschild and Schwarzschild de Sitter black holes (D ≥ 4). For the D-dimensional Schwarzschild anti-de Sitter black hole we also compute these frequencies with a similar method. Moreover, we calculate the electromagnetic normal modes of the D-dimensional anti-de Sitter spacetime. 相似文献
102.
BEPCⅡ500MHz超导腔是BEPCⅡ储存环的关键设备,腔中高次模的分布和阻抗将很大程度上直接影响束流的稳定.因此,研究BEPCⅡ超导腔的高次模分布和高次模吸收器的吸收效果对实现BEPCⅡ指标至关重要.为此,通过改变高次模吸收器的位置、铁氧体吸收材料的长度、厚度以及腔的渐变过渡波导的角度等对BEPCⅡ超导腔高次模阻抗抑制进行了模拟优化研究,从而找到并确定了吸收器对高次模阻抗抑制的最优值.同时,为证实模拟计算结果的正确性,对BEPCⅡ超导模型腔进行了高次模分布和吸收测量,得到了与计算一致的结果.结果表明,经过细致优化腔的高次模吸收器,腔中大部分高次模被深度吸收了,那些具有潜在危险的高次模阻抗值降到了阈值以下,满足BEPCⅡ束流阻抗要求 相似文献
103.
在一新型三维轴对称腔CO2激光器的基础上提出了一种对此激光器位相锁定的方法。通过在输出镜后放置一具有反射和整形作用的凹凸镜,让作为输出注入光束的谐振腔优先起振。此腔输出的光束到达凹凸镜时被其反射。利用重新定义光斑半径的方法,证明此光束能够覆盖其他放电管输出的光束,根据几何光学,此光束能反射进入各个放电管。然后利用光子简并度的概念证明了反射光束能够控制腔内的本征模式,并且数值分析了注入锁定后腔内模式匹配。在反射注入锁定的情况下,给出了数值计算的光强输出及其模拟,结果证明经位相锁定后,激光器输出光束的质量有了很大的提高。 相似文献
104.
We propose a two-color scheme of atom waveguides and one-dimensional (1D) optical lattices using evanescent wave fields of different transverse modes around an optical micro/nano-fiber. The atom guide potential can be produced when the optical fiber carries a red-detuned light with TE01 mode and a blue-detuned light with HEll mode, and the 1D optical lattice potential can be produced when the red-detuned light is transformed to the superposition of the TE01 mode and HE11 mode. The two trapping potentials can be transformed to each other for accurately controlling mode transformation for the red-detuned light. This might provide a new approach to realize flexible transition between the guiding and trapping states of atoms. 相似文献
105.
106.
H. Khosravi A.R. Bahrampour A. Bahari R. Farrahi N. Daneshfar 《Optics & Laser Technology》2008,40(6):779-784
Temporal and spatial analysis of dynamics of hybrid transversely excited atmospheric pressure (TEA)–CO2 lasers is studied using two different models with four and eight energy levels. These models are used for simulation of the laser and computing the output energy. Effects of several parameters such as input energies and gas mixture concentrations (especially presence of CO molecules) are also studied. 相似文献
107.
B. Sen B. Das P. Chatterjee 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2008,49(2):211-216
Nonlinear dust acoustic solitary waves in a dusty plasma are studied for nonzero kinematic viscosity. Sagdeev’s potential
can be obtain upto any order in ϕ. The existence of soliton solution is determined by pseudopotential approach. It is seen
that the electron inertia has a significant effect on the existence of solitary waves in presence of kinematic viscosity. 相似文献
108.
S. Mahmood N. Akhtar 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2008,49(2):217-222
Linear and nonlinear ion acoustic waves in the presence of adiabatically heated ions in magnetized electron-positron-ion plasmas
are studied. The Sagdeev potential approach is employed to obtain the energy integral equation in such a mulitcomponent plasma
using fluid theory. It is found that electron density humps are formed in the subsonic region in magnetized electron-positron-ion
plasmas. The amplitude of electron density hump is decreased with the increase of hot ion temperature in electron-positron-ion
plasmas. However, the increase in positron concentration and obliqueness of the wave increases the amplitude of nonlinear
structure. The increase in positron concentration also reduces the width of the nonlinear structure in a magnetized multicomponent
plasma. The numerical solutions in the form of solitary pulses are also presented for different plasma cases. The results
may be applicable to astrophysical plasma situations, where magnetized electron-positron-ion plasma with hot ions can exist. 相似文献
109.
Mitsuki Yamashita Yuna Kawasumi Yuki Tachibana Dr. Shinnosuke Horiuchi Dr. Koji Yamamoto Prof. Tetsuro Murahashi 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(5):1212-1216
Although small cyclic- and open-chain unsaturated hydrocarbon anions such as cyclopentadienide and open-chain pentadienide are used as the strongly electron-donating auxiliary ligands for metal complexes, more extended π-conjugated unsaturated hydrocarbon anions have rarely been used in coordination chemistry, despite their potential ability to serve as the multiply bridging π-ligands for metal clusters. This work reports isolation of metal chain clusters bearing the multi-dentate, open-chain extended unsaturated hydrocarbon anion ligands. The extended open-chain π-conjugated polyenyl ligands could effectively stabilize oxidized palladium chains, including an unprecedented [Pd4]4+ chain. 相似文献
110.
Reversible Activation of Water by an Air- and Moisture-Stable Frustrated Rhodium Nitrogen Lewis Pair
Dr. María Carmona Dr. Joaquina Ferrer Dr. Ricardo Rodríguez Dr. Vincenzo Passarelli Prof. Dr. Fernando J. Lahoz Dr. Pilar García-Orduña Dr. Laura Cañadillas-Delgado Prof. Dr. Daniel Carmona 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(60):13665-13670
[Cp*Rh(κ3N,N′,P- L )][SbF6] (Cp*=C5Me5), bearing a guanidine-derived phosphano ligand L , behaves as a “dormant” frustrated Lewis pair and activates H2 and H2O in a reversible manner. When D2O is employed, a facile H/D exchange at the Cp* ring takes place through sequential C(sp3)−H bond activation. 相似文献