autoionizing levels in Ca: laser optogalvanic spectroscopy and theoretical analysis

We report the even parity J =4,5 autoionizing spectra of calcium below the 3d threshold, investigated by two-step laser excitation from the 3d4s metastables through the 3d4p , intermediate states and subsequent optogalvanic detection. The 3d4s states are populated by electronic collisions in a d.c. glow discharge sustained in a Ca heat-pipe. More than a hundred resonant transitions have been measured with an accuracy of for the narrow ones using standard laser calibration techniques. The high lying levels are assigned to all expected autoionizing series. Moreover, some levels are observed. The theoretical interpretation is achieved by a combination of the nearly ab initio eigenchannel R-matrix and multichannel quantum-defect (MQDT) methods as well as by an empirical determination of the MQDT parameters in the phase-shifted formulation. Theoretical energy level positions and excitation profiles are compared with the experimental data confirming the identification of the observed structures. Strong mixing between series is found, while the ones do not couple with the series. Further insight into the strong channel mixing in the studied energy range is provided by a comprehensive review of the excitation profiles in the vicinity of the 4p5p perturber as obtained from a number of intermediate levels used in the present and in earlier experiments. Systematic electron correlation trends for series of , and are discussed. Received: 20 November 1997 / Accepted: 15 January 1998     

Luminescence centers in thin films of lead and bismuth tungstates

Luminescence spectra of thin films of PbWO₄ and Bi₂WO₆ are invesigated. The Alentsev-Fock method is used to separate the spectra into elementary components. The emission bands with maxima at 2.8 eV in PbWO₄ and at 2.93 eV in Bi₂WO₆ luminescence spectra are interpreted as the emission of self-localized Frenkel excitons. The bands with maxima at 2.35 and 1.75 eV in PbWO₄ and at 2.35 and 1.9 eV in Bi₂WO₆ are related to oxygen vacancies. L’vov State University, 50, Dragomanov St., L'vov, 290005, Ukraine. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 65, No. 1, pp. 143–145, January–February, 1998.     

具有截断势的空间齐次Boltzmann方程的L2逼近

本文证明了在一定条件下,粘性Boltzmann方程■_tf=Q(f,f) δ△_vf的解当粘性系数δ趋于0~ 时,依L_k~2范数逼近于齐次方程■_tf=Q(f,f)的解。     

Phase properties of a Jaynes-Cummings model with Stark shift and Kerr medium

Phase properties of the field interacting with a two-level atom in a lossless cavity Jaynes-Cummings model, taking into account the level shifts produced by Stark effect with an additional Kerr medium for one-mode are studied using the phase formalism of Pegg and Barnett. It is shown in particular that phase properties of the field reflect the collapse and revival phenomena. The results for the time evolution of the phase probability distribution and the phase fluctuations are obtained. The effect of Stark shift on the phase properties in both the absence and presence of a Kerr medium is analyzed. Phase localization is found for certain choice of the parameters. Received: 27 March 1998 / Revised: 8 June 1998 / Accepted: 9 June 1998     

关于相对论动量定义式的推导方法

指出部分大学物理教材中，用完全非弹性碰撞方法推导相对论动量定义式时，必须附加系统质量守恒这一“预期论据”，从而存在着违反逻辑规则等问题．     

(n,p)和(n,α)激发函数半经验计算方法

在En≤20MeV的情况下,忽略了粒子的二次发射过程,认为复合系统的形成截面是能量相关的,得到了理论模型清晰、公式形式简单的半经验计算方法.在靶核23≤A≤209的范围内,利用大量(n,p)和(n,α)反应的截面实验数据对可调参数进行了研究,得到了参数对靶核的N和Z以及入射能量的依赖关系.对得到的参数做了定性的解释,利用普适参数对(n,p)和(n,α)反应的激发函数做了预言,预言值在其误差范围内与实验数据一致. To simplify the calculation, some assumptions are considered at present work. The preequilibrium emission is the first step in the equilibrium process, which is characterized by exciton n=3 and "never come back" are considered at the preequilibrium emission process; the proton and alpha emissions are only competed with the neutron emission, the second particle emission is neglected. A semiempirical method of the cross section for (n, p ) and (n, α) reactions were obtained on the basis of evaporatio...     

Dynamics of an elastic cylindrical shell with a gas–liquid medium subject to two-frequency vibrational excitation

The paper presents experimental results on nonlinear dynamic processes such as the deformation of the elastic wall of a cylindrical shell filled with a fluid and the formation and clustering of gas bubbles, which interact under two-frequency excitation Translated from Prikladnaya Mekhanika, Vol. 44, No. 11, pp. 112–122, November 2008.     

竖直振动颗粒床中的倍周期运动

实验研究了竖直振动颗粒床中颗粒对容器底部的压力随振动强度的变化情况.发现压力随振动加速度的增加经历倍周期分岔，典型的分岔序列为：2P，4P，混沌，3P，6P，混沌，4P，8P，混沌.观察表明，伴随倍周期分岔现象，在颗粒床底部出现颗粒的聚集态.聚集态内颗粒密堆积在一起并作整体的上下运动.采用完全非弹性蹦球模型分析了颗粒对容器底的冲击力，并给出了倍周期分岔现象的一种解释. 关键词： 颗粒物质 混沌 倍周期分岔 非弹性碰撞     

带电多重数赝快度密度对碰撞对心度依赖关系研究

以核-核碰撞的独立源理论为基础，讨论了(S_NN)^1/2＝１３０ GeV的Au+Au碰撞中，中心快度区带电多重数赝快度密度dn_ch/dη对碰撞对心度的依赖关系.理论结果较好地反映了实验事实. 关键词： 重离子碰撞 带电多重数 赝快度密度 碰撞对心度     

Absorption in a LiF-OH−∶F 2 + crystal induced by flash pumping

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