Structural and Magnetic Characteristics of Nanogranular Co–Al2O3 Single- and Multilayer Films Formed by the Solid-State Synthesis

The results of structural and magnetic investigations of nanogranular Co–Al₂O₃ films formed from Co₃O₄/Al thin-film layered structures upon vacuum annealing are reported. The Co₃O₄/Al films have been obtained by sequential reactive magnetron sputtering of a metallic cobalt target in a medium consisting of the Ar + O₂ gas mixture and magnetron sputtering of an aluminum target in the pure argon atmosphere. It is shown that such a technique makes it possible to obtain nanogranular Co–Al₂O₃ single- and multilayer thin films with a well-controlled size of magnetic grains and their distribution over the film thickness.

     

Graph model for calculating the properties of saturated monoalcohols based on the additivity of energy terms

A 16-constant additive scheme was derived for calculating the physicochemical properties of saturated monoalcohols CH₄O-C₉H₂₀O and decomposing the triangular numbers of the Pascal triangle based on the similarity of subgraphs in the molecular graphs (MGs) of the homologous series of these alcohols. It was shown, using this scheme for calculation of properties of saturated monoalcohols as an example, that each coefficient of the scheme (in other words, the number of methods to impose a chain of a definite length i ₁, i ₂, … on a molecular graph) is the result of the decomposition of the triangular numbers of the Pascal triangle. A linear dependence was found within the adopted classification of structural elements. Sixteen parameters of the schemes were recorded as linear combinations of 17 parameters. The enthalpies of vaporization L _{298 K}⁰ of the saturated monoalcohols CH₄O-C₉H₂₀O, for which there were no experimental data, were calculated. It was shown that the parameters are not chosen randomly when using the given procedure for constructing an additive scheme by decomposing the triangular numbers of the Pascal triangle.     

Nonlocal ion transport in a weakly ionized nonequilibrium plasma

Nonlocal ion transport in a weakly ionized plasma with a strong electric field is analyzed. It is assumed that charge-exchange interactions are the main mechanism of ion scattering. Ion density and drift velocity are determined for nonuniform time varying electric field by using both the direct solution of the kinetic equation and the Chapman-Enskog-type approach. The ion mean velocity is given by an integro-differential operator applied to the electric field. Ion density and drift velocity exhibit resonant behaviour when ω≃kW0, which corresponds to the resonance between ions moving with average velocity W₀ and wave traveling with the phase velocity ω/k     

Sorption of cadmium ions from aqueous solutions onto nanoporous modified carbon sorbents

Physicochemical properties of nanoporous modified carbon sorbents and sorption of cadmium ions (0.1–20 mg L^?1) onto them from nitrate solutions at pH 5–7 were studied. The acid-base nature of functional oxygen-containing groups on the carbon surface of the sorbents was determined. The ability to sorb cadmium ions depends on the kind of chemical modification of the sorbent surface.     

Influence of flow shear on localized Rayleigh–Taylor and resistive drift wave instabilities

The impact of velocity shear on the localized solutions of Rayleigh–Taylor (RT) and resistive drift wave (DW) instabilities has been investigated. Slab geometry is used, and the plasma density gradient is assumed to have a finite spatial structure. It demonstrates that the velocity shear has quite different effects on these instabilities: while it stabilizes RT instability and causes tilting of the eddies of equipotential contour, it has a very mild impact on the resistive DW instability and simply shifts the eddies with no tilting.     

Transport of meso-scale structures in tokamak edge plasmas

We review possible mechanisms of blobby transport in fusion-related plasmas. The models dealing with the effective plasma gravity and caused by both T _e and parallel shear of E × B drift instabilities are considered.Presented at the Workshop Electric Fields Structures and Relaxation in Edge Plasmas, Nice, France, October 26–27, 2004.     

Approximate similarity criterion for an arc of self-adjusting length burning in a plasma generator with vortex gas stabilization

Use of the theory of similarity to analyze experimental data on arc burning in plasma generators [1–3] has made possible a qualitative jump in methods of designing such devices. The success of this approach has raised the problem of finding similarity criteria giving a good generalization for each specific plasma generator model with allowance for the corresponding arc burning characteristics.We have obtained an approximate similarity criterion for the dimensionless potential drop along an arc burning in a plasma generator with vortex gas stabilization in the case when the length of the arc is determined by shunting [4], The results of an analysis of experimental data on arcs in plasma generators with air vortex stabilization are presented.In conclusion the author thanks B. A. Uryukov for his comments and A. D. Lebedev for assisting with the experiments. He is also grateful to M. F. Zhnkov for his constant interest.