Modification of mixed conducting Ba<Subscript>0.5</Subscript>Sr<Subscript>0.5</Subscript>Co<Subscript>0.8</Subscript>Fe<Subscript>0.2</Subscript>O<Subscript>3–δ</Subscript> by partial substitution of cobalt with tungsten

The Ba_0.5Sr_0.5Co_0.8–xW_xFe_0.2O_3–δ (х = 0–0.1) materials prepaMIECred by partial substitution of cobalt in BSCF with tungsten were studied. The tungsten solubility limit in the structure of cubic perovskite BSCF was shown to be ~2%. The doping with the highly charged W⁶⁺ (2%) cation improved the functional properties of BSCF: it increased the oxygen permeability and membrane stability in the CO₂-containing atmosphere and suppressed the cubic–hexagonal perovskite polymorphic transition. This stabilizes high oxygen fluxes during long-term stability tests.     

Possibility of electrochemical refining of uranium alloys with aluminum in chloride melts

Selectivity of liquid aluminum electrodes in separation of uranium from fission products was studied. The composition of a salt electrolyte and modes of electrolysis for electrorefining of uranium-aluminum alloys in molten chlorides were determined.     

Modelling and studying fuzzy dynamical systems

The goal of this paper is to further develop the Yu. P. Pyt'ev fuzzy set theory. Based on this, the author suggests a new class of differential equations for describing fuzzy dynamics. Translated from Sovremennaya Matematika i Ee Prilozheniya (Contemporary Mathematics and Its Applications), Vol. 53, Suzdal Conference-2006, Part 1, 2008.     

Formation of the Ni–CrOx/MgO and Ni/MgO Catalysts for Carbon Dioxide Reforming of Methane

Temperature-programmed reduction by hydrogen, temperature-programmed desorption of O₂, local X-ray spectral analysis, and scanning electron microscopy are used to study redox processes occurring on the Ni–Cr₂O₃/MgO and Ni/MgO catalysts for carbon dioxide reforming of methane. The reduction of Ni/MgO leads to the formation of nickel clusters distributed over the surface of MgO. During the reduction of NiO–Cr₂O₃/MgO, chromates are transformed into chromites, and then nickel is formed by the reduction of spinel NiCr₂O₄. Reoxidation leads to the oxidized structures NiO, NiCr₂O₄, and NiCrO₄.     

Numerical analysis of feasibility of the neutral stability conditions for shock waves in the problem of a van der waals gas flow past a wedge

By means of numerical calculations, the question is answered of the feasibility of the conditions of neutral stability for shock waves in the problem of a flow of real gases past a wedge.     

Absorption of electromagnetic waves in a nonmagnetic conductor-ferromagnet structure

The absorption coefficient of electromagnetic waves in the structure that consists of a nonmagnetic conducting layer having the width less than that of the skin layer and a ferromagnetic layer (ferrite) has been studied both analytically and numerically. The frequency dependences of the absorption coefficient of electromagnetic waves have been obtained. It has been shown that, for particular parameters of the structure, the absorption coefficient can be close to unity over a wide frequency range due to the formation of a standing electromagnetic wave in the upper conducting layer.     

Thermochemistry and Reactivity of Lattice Oxygen in V–Sb Oxide Catalysts for the Oxidative Dehydrogenation of Light Paraffins

Differential scanning calorimetry is used to study in situthe properties of strongly bound (lattice) oxygen in vanadium-containing supported catalysts for the oxidative dehydrogenation of paraffins C₂–C₄. Evidence is found that the process occurs via a stepwise redox mechanism with the participation of lattice oxygen from the catalyst. When the supported component is modified by an antimony additive, the amount of reactive oxygen increases and redox processes accelerate. Simultaneously, the rate of coke formation decreases. Additional modification by Bi and Ba leads to a further increase in the amount of reactive oxygen. In all cases, oxygen bound to vanadium atoms is responsible for the redox properties of the systems. The observed effects are analyzed from the standpoint of the ratio between different forms of active oxygen.     

A study of magnetic ordering in LaMnO<Subscript>3+δ</Subscript> single crystals

The magnetic state of LaMnO_3+δ single crystals with different contents of nonstoichiometric oxygen grown by electric deposition is studied by measuring the temperature and field dependences of magnetization for different orientations of a magnetic field. The results obtained are analyzed in terms of a two-phase magnetic-state model.