South Russia State Technical University

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Novocherkassk, Russia
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Chernyshev V.M.,South Russia State Technical University | Astakhov A.V.,South Russia State Technical University | Starikova Z.A.,RAS Nesmeyanov Institute of Organoelement Compounds
Tetrahedron | Year: 2010

Reaction of 3,5-diamino-1-R-1,2,4-triazoles (R=Ph, Bn) with β-keto esters results in the reversible formation of N-(5-amino-1-R-1,2,4-triazol-3-yl)-substituted enaminoesters (8). Subsequent transformations depended on the reaction conditions. Compounds 8 undergo intermolecular reactions of condensation and amidation in the absence of solvent. However, in the presence of acetic acid they form 3-amino-5-oxo-2-R-2,5-dihydro-[1,2,4]triazolo[4,3-a]pyrimidin-4-ium-8-id es (10) followed by rearrangement to 3-amino-1-R-[1,2,4]triazolo[4,3-a]pyrimidin-5-ones (11). The transformation of 10 into 11 represents a new type of rearrangement in the azolopyrimidine series. Heating of enaminoesters 8 in ethanol with sodium ethoxide present, proved to be a suitable method for the preparation of the mesoionic compounds 10. © 2010 Elsevier Ltd. All rights reserved.


Talanov V.M.,South Russia State Technical University | Shirokov V.B.,Russian Academy of Sciences
Acta Crystallographica Section A: Foundations of Crystallography | Year: 2012

The possible distortions in the spinel structure resulting from rotation of the tetrahedra and octahedra have been investigated by a group-theoretical method. The possibility of the existence of 28 phases of rotation of the tetrahedra and five phases of rotation of the octahedra has been shown. In all these phases the polyhedra are equivalent, but their orientation can be different. Among the phases of the tetrahedra rotation there is one phase of pure rotation, i.e. not accompanied by additional (not rotation) distortions of the structure. Of the five phases of the rotation of the octahedra three phases can be obtained only by pure rotation of the octahedra. © 2012 International Union of Crystallography Printed in Singapore-all rights reserved.


Mukovnin A.A.,South Russia State Technical University | Talanov V.M.,South Russia State Technical University
Solid State Communications | Year: 2012

Within the framework of the phenomenological theory of the second-order phase transitions for the crystals undergoing structural transformations, induced by irreducible representations with symmetry group L=3m, all possible types of phase diagrams are constructed. Conditions of realization of each type of phase diagrams are found in the approach of the thermodynamic potential of the sixth power of expansion on order parameter components. The equations for calculation of tricritical and triple point coordinates are received. In the case of spinel-type structure, qualitative agreement between the results of theoretical calculations of phase diagrams and experimental phase diagrams is observed. © 2012 Elsevier Ltd. All rights reserved.


Nekrasov S.A.,South Russia State Technical University
Russian Journal of Electrochemistry | Year: 2013

The problems of distribution of ion concentrations, electric field, and Lorentz force in the flux of the solution of electrolyte under external magnetic field are solved. The existence of the diffuse ion layer in magnetic flow of the dilute electrolyte is established and its characteristics are studied. © Pleiades Publishing, Ltd., 2013.


Talanov V.M.,South Russia State Technical University | Shirokov V.B.,South Russia State Technical University
Acta Crystallographica Section A: Foundations and Advances | Year: 2014

Group-theoretical methods of the Landau theory of phase transitions are used to investigate the structures of ordered spinels. The possibility of the existence is determined of 305 phases with different types of order in Wyckoff position 8a (including seven binary and seven ternary cation substructures), 537 phases in Wyckoff position 16d (including eight binary and 11 ternary cation substructures), 595 phases in Wyckoff position 32e (including seven binary and four ternary anion substructures) and 549 phases with simultaneous ordering in Wyckoff positions 8a and 16d (including five substructures with binary order in tetrahedral and octahedral sublattices, two substructures with ternary order in both spinel sublattices, and nine substructures with different combined types of binary and ternary order). Theoretical results and experimental data are compared. Calculated structures of the spread types of ordered low-symmetry spinel modifications are given. © 2014 International Union of Crystallography.


Yatsenko E.A.,South Russia State Technical University
Glass Physics and Chemistry | Year: 2011

The compositions of single-layer low-melting white enamels with a decreased (no higher than 720°C) firing temperature without toxic and expensive components have been developed. The mechanisms of formation of the developed single-layer low-melting enamels on a steel preliminarily treated by means of deposition of copper, nickel, and zinc films through electroplating, as well as by boronizing, have been investigated. © 2011 Pleiades Publishing, Ltd.


Dovzhenko I.G.,South Russia State Technical University
Glass and Ceramics (English translation of Steklo i Keramika) | Year: 2014

The effect of metallurgical slag on the drying properties of ceramic bodies is investigated. It is shown experimentally that fine-grain slag makes the raw clay material less sensitive to drying. It is confirmed by means of electron microscopy, infrared spectroscopy and simultaneous thermal analysis that slag grains possess a highly developed porous surface. As a result some of the water introduced during the formation of ceramic bodies is adsorbed on the surface of the slag grains. It is shown that fine-grain metallurgical slag is an effective thinner in ceramic bodies. © 2014 Springer Science+Business Media New York.


Ivanov V.V.,South Russia State Technical University | Talanov V.M.,South Russia State Technical University
Crystallography Reports | Year: 2010

The principle of modular crystal structure has been formulated and the possibility of choosing a module of a specified structure type for its subsequent modular design is discussed. The modular characteristics of some structure types based on cubic close packing (fundamental and basic modules and the module that can be used to obtain a certain variety of modular structures related to the initial parent type) are described. Possible ways to obtain such a module and the algorithm for choosing it are considered. A comparative analysis of the theoretically derived module with the modules of experimentally determined modular structures is performed by the example of spinelloids (materials with spinel-like structure). © 2010 Pleiades Publishing, Ltd.


Talanov V.M.,South Russia State Technical University | Mukovnin A.A.,South Russia State Technical University
European Physical Journal B | Year: 2013

The detailed research of phase diagrams is carried out for Landau's thermodynamic potential with ℒ = 3m symmetry group. All possible types of phase diagrams for the sixth-order expansion of thermodynamic potential in terms of the order parameter components are received. Realization conditions for each type of phase diagrams are established, conditions of the multicritical point splitting are studied, and the equations for calculation of tricritical and triple points coordinates are obtained. Surfaces of order parameter components as functions of thermodynamic potential parameters are designed. Qualitative correspondence of phase diagrams theoretical calculations results and an experimental phase diagram is noted at the example of spinel structural type. © 2013 EDP Sciences, SIF, Springer-Verlag Berlin Heidelberg.


Mukovnin A.A.,South Russia State Technical University | Talanov V.M.,South Russia State Technical University
Russian Journal of Physical Chemistry A | Year: 2012

The breakup of multicritical points is studied in detail within the phenomenological theory of second-order phase transitions for a thermodynamic potential invariant with respect to the C3v (3m) group of transformations. The general conditions of this breakup are obtained and possible types of derived diagrams are plotted from a parent phase diagram containing a multicritical point. Examples of experimental phase diagrams are given that qualitatively confirm the results from theoretical and computer simulations of phase equilibria. © Pleiades Publishing, Ltd., 2012.

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