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31.
A. Wnuk M. Kaczkan R. Piramidowicz R. Mahiou G. Bertrand M.-F. Joubert 《辐射效应与固体损伤》2013,168(1-6):469-473
The dynamics of up-conversion, green emission under excitation at different infra-red wavelength in Ho3? doped ZBLAN fiber is reported. Under infrared, 890 nm quasi cw pumping the complicated temporal behavior of the up-conversion signal is strongly influenced by the intermediate 5I5 state cross relaxation. The mechanisms of the observed up-conversion processes are proposed and the time evolution of the 5S2 population is described by the rate equation model. Parameters of the model are determined and numerical simulations of the excited state dynamics are performed. 相似文献
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Norio Kondo 《国际流体数值方法杂志》2012,70(2):158-185
We present numerical results for in‐line and cross‐flow vibrations of a circular cylinder, which is immersed in a uniform flow and is elastically supported by damper‐spring systems to compute vibrations of a rigid cylinder. In the case of a circular cylinder with a low Scruton number, it is well‐known that two types of self‐excited vibrations appear in the in‐line direction in the range of low reduced velocities. On the other hand, a cross‐flow vibration of the circular cylinder can be excited in the range of high reduced velocities. Therefore, we compute the flow‐induced vibrations of the circular cylinder in the wide range of the reduced velocities at low and high Scruton numbers and discuss about excitation mechanisms in the in‐line and cross‐flow directions. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
35.
The steady state and time domain spectroscopy of 9-aminoacridinium hydrochloride have been studied. 9-aminoacridine (I), 9-aminoacridinium
(II) and the double protonated ion (III) follow Waterman’s principle with respect to their spectra and lifetimes. It is established
that the excimer formation in (II) is from the ground state dimers which undergo either thermally-activated radiationless
excimer conversion or a geometrical rearrangement in the excited state at room temperature. The quenching of monomer emission
by dimers or foreign quenchers (KI) is found to be of transient nature as suggested by the continuum model.
The authors felicitate Prof. D S Kothari on his eightieth birthday and dedicate this paper to him on this occasion. 相似文献
36.
The evolution of nonlinear Langmuir waves in the interplanetary medium is investigated by appropriately accounting for the
random density irregularities of the medium. A pair of modified Zakharov equations, which describe these waves, is solved
numerically as an initial value problem for large scale (≫ 102 km) initial pertubations. For an ion acoustic-Langmuir solitary wave, the random irregularities damp the Langmuir wave by
way of scattering and let the ion density perturbation radiate away in a few days. However an initial solitary or shock-like
Langmuir wave excites the ion density perturbations within a fraction of a second, and then itself gets damped. These effects
will strongly decelerate the collapse of large scale Langmuir waves. The possibility of detecting these processes, by means
of interplanetary scintillation, is discussed.
The authors felicitate Prof. D S Kothari on his eightieth birthday and dedicate this paper to him on this occasion. 相似文献
37.
本文根据空心阴极放电中电子能量分布的物理图象,分析了原子从低激态向高激态弛豫的可能途径。建立高低激态集居数密度增量的关系。讨论高激态集居数密度增量获得可观量的条件。根据此条件分别选取钠原子的基态3s~2S_(1/2)和铜原子的亚稳态4s~2D_(3/2)为与激光共振的下能级,并激发具有较大自发发射几率的3s~2S_(1/2)→3p~2P°_(1/2)(和3p~2P°_(3/2))和4s~2D_(3/2)→4p~2P°_(1/2)跃迁,在远离上能级的高激态上观测到敏化荧光,并精确测得这些态的自发发射系数比值,而在更高激态上没有观测到敏化荧光,表明讨论中提出的条件是合理的。 相似文献
38.
GaAs:Cr探测器中子辐照改性研究 总被引:3,自引:0,他引:3
介绍了一种新型脉冲辐射探测器以及提高其性能的一种方法,并报告了探测器性能与中子积分通量关系的实验结果。 相似文献
39.
40.
Hai Ming Yu Liu Hui Nie Baorui Ren Jianping Xie Jingren Qian 《Chinese Journal of Lasers》1993,2(5):393-397
Amplification of spontaneous emission(ASE) in 4m Nd~(3 )-doped fiber pumped by Ti : Al~2O_3 tunable laser is studied theoretically and experimentally. The output of 2.64mW from ASE source pumped at 833 nm is obtained and the experimental results of ASE source are compared with that of Nd~(3 )-doped fiber ring laser. 相似文献