The coronograph developed for the KORONAS-F orbital solar observatory

We present the design and optical scheme of the externally occulted coronograph developed for the KORONAS-F orbital solar observatory.     

Study of chromatographic characteristics of inorganic analytes in biopartitioning micellar chromatography with ion‐pair additives

The chromatographic behavior of model ions of biomedical and environmental significance was investigated by using nonionic micellar mobile phases modified with ion‐pair additives. The influence of concentrations of polyoxyethylene (23) lauryl ether and ornithine hydrochloride in the mobile phase on the retention factors of chromium (III), chromium (VI), iodide and bromide ions was studied. The possible mechanisms of retention of the mentioned ions in biopartitioning micellar chromatography with zwitter ion‐pair additives were proposed. Copyright © 2010 John Wiley & Sons, Ltd.     

Beam shear-Alfven instability in two-component tokamak

The authors consider from a theoretical standpoint the excitation of shear-Alfven waves in a tokamak in which the plasma contains a fast ion group. It is assumed that the fast ions are formed as a result of fast neutral atoms injected into the tokamak. An expression is derived for the growth rate of the shear-Alfven oscillations, with an arbitrary relationship between the transverse wave length and the dimension of the Larmor and drift orbits. The authors analyse the part played by the finite orbit effect in the case of a longitudinal beam with a small Maxwellian velocity spread and an arbitrary ratio between the directed velocityV ₀ and the Alfven velocityc _A . It is demonstrated that at a finite ratioV ₀/c _A two physically different types of oscillations may build up, corresponding to the two signs of the ratio/k _¦ ( is the oscillation frequency,k _¦ is the longitudinal wave number). The growth rate for perturbations with /k_¦<0 is greater than for /k>0.     

Physics of the amplification of vortex disturbances in shear flows

The physics of the linear mechanism of the amplification of vortex disturbances in shear flows, which is due to the nonorthogonality of the eigenfunctions of the problem in the linear dynamics, is described. To obtain the clearest and simplest picture, a parallel flow with a linear velocity shear is studied, and the vortex disturbances are represented in the form of plane waves — spatial Fourier harmonics. On this level our physical approach is consonant with the nonmodal mathematical analysis of linear processes in shear flows, which has been actively cultivated in the last few years. The physics presented explains the non-monotonic growth of vortex disturbances in time at the linear stage of evolution. Moreover, being universal, the “language” employed in this work can also be used to describe the amplification of potential (acoustic) disturbances. Pis’ma Zh. éksp. Teor. Fiz. 63, No. 7, 517–522 (10 April 1996)     

A two-sided Arnoldi algorithm with stopping criterion and MIMO selection procedure

In this paper we introduce a two-sided Arnoldi method for the reduction of high order linear systems and we propose useful extensions, first of all a stopping criterion to find a suitable order for the reduced model and secondly, a selection procedure to significantly improve the performance in the multi-input multi-output (MIMO) case. One application is in micro-electro-mechanical systems (MEMS). We consider a thermo-electric micro thruster model, and a comparison between the commonly used Arnoldi algorithm and the two-sided Arnoldi is performed.