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Yekaterinburg, Russia

Leontyev V.,RAS Institute of Metallurgy
Physica Status Solidi (B) Basic Research | Year: 2013

Nanoparticles of pure Ni and Ni-Cu solid solution were synthesized by the sol-gel method at 400-600°C. The particle sizes and values of specific surface of powders were dependent on the synthesis temperature. The magnetization of the obtained powders was studied using a high-temperature magnetic balance. The Curie temperature for particles of pure nickel did not depend on their size but the specific magnetization at 300K decreased linearly with increasing specific surface area of particles. For particles of the Ni-Cu binary solid solutions, the Curie temperature and values of magnetization increased with decreasing particle size for particles with diameters up to values less than 100nm. The amount of adsorbed copper on the particles surface, the change of nickel concentration in the volume of the particles and the Curie temperatures, depending on the Cu (Ni) concentration in a volume of particles, were calculated using the Gibbs equation. The calculations made in the framework of a perfect solution showed qualitative agreement between experimental and calculated values of the Curie temperature for the system Ni-Cu. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Source

Nechaev Y.S.,RAS Institute of Metallurgy
International Journal of Hydrogen Energy | Year: 2011

Thermodynamic and experimental backgrounds of the condensed hydrogen storage problem are considered. It results in developing an effective method of producing a high-density solid hydrogen carrier by means of hydrogen intercalation in carbonaceous nanomaterials at relevant temperatures and pressures (at the cost of the hydrogen association energy). This is a much more technological method, in comparison with the current megabar compression dynamic and static methods. As is also shown, one of the known processes of chemisorption of hydrogen in some carbonaceous nanostructures can be related to formation of graphane-like (i.e., carbohydride-like) nanoregions. By using gravimetric and electron microscopy data, the density values ( ρH=0.7±0.2g(H2)/cm3(H 2),ρH=0.28±0.08g(H2)/cm3(system)), of the intercalated solid molecular (i.e., reversible) hydrogen in graphane-like nanofibers (≥ 17 wt% H2) has been defined. It corresponds to a much more efficient hydrogen storage technology, in comparison with the current ones, and relevance to the U.S. DOE requirements and targets for 2015. © 2011, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved. Source

Korzhuev M.A.,RAS Institute of Metallurgy
Journal of Electronic Materials | Year: 2010

Symmetry analysis has been applied to thermoelectric energy converters [thermoelectric generators (TEG), coolers (TEC), and heaters (TEH)] with inhomogeneous legs. The features of the crystallographic symmetry of thermoelectric materials and the symmetry of legs, thermocouples, and modules are studied. The effect of symmetry on the figure of merit Z of thermoelectric energy converters is considered. A general rule for proper placement of legs in thermoelectric converters is developed. A modified tetratomic classification for thermoelectric energy converters with inhomogeneous legs (TEG a, TEG b, TEC, and TEH) is proposed. An increase in Z for thermoelectric energy converters with inhomogeneous legs is due to the bulk thermoelectric effect. An increase in Z gives the reduction of irreversible processes in the modules (Joule heating and thermal conductivity), accompanying breaking of the symmetry of the legs. It is found that violations of the symmetry requirements can lead to significant energy losses in converters. © 2010 TMS. Source

Pogorelova A.V.,RAS Institute of Metallurgy
Proceedings of the 10th (2012) ISOPE Pacific/Asia Offshore Mechanics Symposium, PACOMS 2012 | Year: 2012

This paper studies the three-dimensional unsteady problem of the hydroelastic behavior of a floating infinite plate under the impact of waves generated by moving loads on ice plate in conditions of sloped bottom. An analytic solution of the problem is found by integral transformations and asymptotic expansions. The amplitude is analyzed for various values of bottom slope, basin depth, plate thickness, vehicle length, deceleration and acceleration coefficients. © 2012 by International Society of Offshore and Polar Engineers. Source

Belousov V.V.,RAS Institute of Metallurgy
Corrosion Science | Year: 2010

An electrochemical mechanism of hot corrosion of the Bi2O3-deposited copper is proposed. Oxygen ion transport across the oxide scale with liquid-channel grain-boundary structure (LGBS) is the rate-limiting step in the overall mechanism. The calculated and experimental values of the rate constant for hot corrosion of Bi2O3-deposited copper are of the same order of magnitude, which shows agreement between theory and experiment. © 2009 Elsevier Ltd. All rights reserved. Source

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