Leptonic constant of the pseudoscalar <Emphasis Type="Italic">B</Emphasis><Subscript><Emphasis Type="Italic">c</Emphasis></Subscript> meson

We calculate the leptonic constant for the pseudoscalar ground state of the B _c meson in the framework of a QCD-motivated potential model taking into account the two-loop anomalous dimension for the heavy quark current in nonrelativistic QCD as matched with full QCD.     

基于成像机理的小波包变换多聚焦图像融合

由于可见光成像系统的聚焦范围有限,因而在成像过程中,除聚焦良好的物体能生成清晰的图像外,该物体前后一定距离外的所有物体都将呈现不同程度的模糊.为了获得场景内所有物体均清晰的图像,在分析了多聚焦图像成像机理的基础上,提出了一种基于小波包变换的融合方法.它是将成像系统先聚焦在一部分对象上,得到其清晰的图像;然后再将其聚焦在另一部分对象上,得到另一清晰的图像;最后把这两幅实验图像加以融合,从而获得场景内所有物体均清晰的图像.实验结果表明,基于小波包变换的融合方法能够将信号的频带进行多层次划分,对高频成分也能进一步地分解,可有效综合多聚焦图像.     

An asymptotic solution of the Cauchy problem for the Davey-Stewartson-I equation

We construct and asymptotic solution of the Cauchy problem for the Davey-Stewartson-I equation as t→∞. The solution, which is of order t⁻¹, is rapidly oscillating. The envelope of the oscillations can be defined by an integral equation. Translated from Teoreticheskaya i Matematicheskaya Fizika, Vol. 114, No. 1, pp. 104–114, January, 1998.     

Lasing of iodine in the fullerene-oxygen-iodine system

The possibility of lasing in the fullerene-oxygen-iodine system with optical excitation of fullerene is studied. Laser radiation with an energy of 25 mJ and a pulse duration of 5–10 ms is obtained.     

Pressure recovery system for a high-power HF/DF laser: implementation practice

The matter of development of a high-performance pressure recovery system (PRS) for a high-power HF/DF laser is discussed. A sequence of design steps is proposed, which involves estimation of basic characteristics of PRS components with the help of one-dimensional integral and semi-empirical procedures; simulation, to be performed using three-dimensional non-stationary Navier — Stokes equations; experimental modelling aimed at verification of the calculation procedures and at refinement of obtained parameters; and a fullscale experiment. An ejector-type system providing for recovery of pressure from 12 Torr to atmospheric pressure in the gas-dynamic system of an HF/DF laser of several-tens-kilowatt power is developed. Matching conditions for parameters of individual PRS components as well as joint functioning of the PRS with a continuous chemical laser in an integral complex are analysed. Conditions for minimization of mass-dimensional characteristics of the laser-PRS complex necessary for the development of ground-based mobile systems are identified.