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991.
分布在弱电介质溶液中的电磁力(Lorentz力),可以有效地控制边界层的流动.利用以转动水槽为主的实验系统和基于双时间步Roe格式的数值方法,对翼型绕流的电磁控制进行了实验和数值研究.结果表明,对于一定攻角的翼型,电磁力可以控制其绕流形态.当电磁力方向与流动方向相同时,可以抑制分离,消除涡街,其效果与减小攻角类似.当电磁力的方向与流动方向相反时,可在流场中形成大涡组成的涡街,增强流体的混合能力,其效果与增大攻角类似. 相似文献
992.
We report a high-power thin Nd:YAG slab laser with slab dimension of 1 × 10 ×60 (mm) partially edgepumped by diode laser arrays. Passive Q-switching is achieved with a Cr^4+ :YAG microchip adopted as the saturable absorber mirror. The pulse duration is around 10 ns while the pulse repetition rate is higher than 10 kHz. The average output power of 70 W is obtained with a slope efficiency of 36%. The diffraction limited beam quality in the thickness direction is obtained by controlling the pump beam diameter inside the slab. The laser head is very compact with size of only 60 × 74×150 (mm). 相似文献
993.
We report on hundred watts range ytterbium-doped all-fiber laser assembly based on the master oscillator power amplifier structure. It consisted of an oscillator and an amplifier with all-fiber components. And fiber fusion splice made the laser be an integrated fiber system. It generated up to 175.5 W of continuouswave (CW) output power at 1085 nm with more than 75% extraction efficiency in the amplifier when the total coupled pump power into the double clad fiber was 270 W. 相似文献
994.
Xe-Kr laser induced collisional ionization system and experimental preparation of its initial state: Four-photon resonant excitation 下载免费PDF全文
This paper proposes a novel one-colour Xe-Kr laser induced collisional ionization system. Considering the level scheme of the system, it finds that the initial state of the reaction--the four 4f levels with even J of Xe-can be prepared through method of four-photon resonant excitation by dye laser with wavelength of -440 nm. Absorption of an additional photon (the transfer laser) of the same wavelength will complete the laser induced collisional ionization process. The resonance enhanced ionization spectrum of Xe by four laser photons at -440nm is measured through time-of-flight mass spectrometry, this aims at the preparation of the initial state of the system proposed. The Stark broadening of the measured spectrum is observed and consistent with the previous study. Analysis of the measured resonance ionization spectrum implies the feasibility of -440 nm four-photon resonant excitation of the initial 4f state of the Xe Kr system proposed in this paper, which prepares for a further experiment of laser induced collisional ionization. 相似文献
995.
A protocol for controlled remote implementation of a partially unknown operation on an arbitrary quantum state is proposed.
In this protocol, a task can be performed using a GHZ state shared among three distant parties: Alice, Bob and the controller
Charlie. This protocol is also generalized to the multi-party control system based on sharing an N-qubit GHZ state.
Supported by the Natural Science Youth Teacher Foundation of Xuzhou Institute of Technology, China (Grant No. XKY2007317) 相似文献
996.
The emergent light distribution of a new type of contact laser scalpel is measured in three different states using a light sensor. The relationship between the angle and the light intensity is analyzed. The results show that the strongest light is emitted from two sides and the front of the scalpel. The light from the front mainly plays a role of cutting. The light from two sides contributes to stanch the wound so as to remain a clear visual field during the surgery. It also helps to increase the cutting efficiency. 相似文献
997.
We investigate intersubband Rabi flopping in modulation-doped semiconductor quantum wells with and without the propagation effects, respectively. It is shown that propagation effects have a larger impact on Rabi flopping than the nonlinearities rooted from electron-electron interactions in multiple quantum wells. By using ultrashort π pulses, an almost complete population inversion exists if the propagation effects are not considered; while no complete population inversion occurs in the presence of propagation effects. Furthermore, the magnitude of the impact of propagation effects may be controlled by varying the carrier density. 相似文献
998.
Ai Hua Fan 《Journal d'Analyse Mathématique》2002,86(1):271-287
Let β > 1 be a Pisot number andg be a positive Hölder continuous function with period one and g(0) = 1. The multiperiodic functionG(ξ)=Π n=0 ∞ g(ξ/βn) is studied and the asymptotic behaviour ofI G(T) = ∫ 0 T G(ξ)dξ investigated. We prove that the limit of logI(T)/ logT exists asT tends to infinity. We also provide a method to calculate this limit for the caseg(ξ) = cos2 2πξ, corresponding to the Fourier transform of the Bernoulli convolution associated to the golden number (or some of its generalizations). 相似文献
999.
For a sequence (cn) of complex numbers, the quadratic polynomials fcn:= z2 + Cn and the sequence (Fn) of iterates Fn: = fcn ο ⋯ ο fc1 are considered. The Fatou set F(Cn) is defined as the set of all
such that (Fn) is normal in some neighbourhood of z, while the complement J(Cn) of F(cn) (in
) is called the Julia set. The aim of this paper is to study the stability of the Julia set J(Cn) in the case where (cn) is bounded. A problem put forward by Brück is solved. 相似文献
1000.
Bao-Li An Jian-Xin ShiWai-Kwok Wong Kok-Wai CheahRong-Hua Li Yan-Sheng YangMeng-Lian Gong 《Journal of luminescence》2002,99(2):155-160
A novel organic ligand, 6-parachloroaniline carbonyl 2-pyridine carboxylic acid, and the corresponding europium complex, tris(6-parachloroaniline carbonyl-2-pyridine carboxylate) europium (III) have been designed and synthesized. The results showed that the synthesized product was a conjugated complex, emitting remarkable strong red luminescence, and was a good red luminescence material with good thermal stability. The 5D0 lifetime of Eu3+ in the complex was examined using time-resolved spectroscopic analysis. The lifetime values for 1.0×10−5 mol/l ethanol solution of the complex and for the complex solid were 0.49±0.01 and 1.94±0.01 ms, respectively. 相似文献