"This review covers various methods of synthesis LaMnO3 ferroics. The general analysis of the solid-phase synthesis reactions methods and wet methods (sol-gel, sorption, co-precipitation) are carred out. The original results of LaMnO3 syntheses from various precursors by means of the in situ method are showned. The advantages and disadvantages of different methods of synthesis are determined. The analysis of synthesis LaMnO3 ferroics published data is shown:
- the structure formation of LaMnO3 in perovskite-type phases occurs at different temperatures, depending on precursors states;
- LaMnO3 perovskite phases differ in symmetry and unit cells parameters at room temperature, depending on the preparation conditions;
- the highest synthesis temperature of LaMnO3 are typical for solid phase reactions method (950-1050 ° C), the lowest - for wet synthesis methods (500-700 ° C);
- the synthesis conditions effect the stoichiometry of LaMnO3 for oxygen content.
Our studies of structure formation processes of LaMnO3 by in situ method are allowed to define the role of precursors states at synthesis of solid phase reactions methods, adsorption, co-precipitation and sol-gel mixtures.
It is determined that in samples prepared by wet chemical methods, the formation processes of LaMnO3 perovskite phases occur at lower temperatures than by solid phase reaction (sol-gel precursor - 500 <T <600 ° C; precursors obtained by coprecipitation and sorption methods - at 600 <T <700 ° C and 700 <T <800 ° C, respectively).
Keywords: ferroics, LaMnO3, X-ray diffraction, solid-phase synthesis, sol-gel synthesis, sorption, co-precipitation
Oxide bronzes MxEO3 (M–Na,K; E – W,Mo) are the inorganic materials for technics and chemical technology. Its properties, for example stability in wide interval of temperatures, are of great practical interest (electrodes for fuel elements, electronic apparatuses and others). In this article the results of studies of thermostability of sodium and potassium tungsten and molybdenum bronzes in atmosphere and vacuum condition at the temperatures range 20-1110°C were found. The samples are prepared by electrolysis of melts of sodium and potassium isopolytungstates and molybdates. Dates for bronzes Na0.92WO3 , Na0.68WO3 , Na0.53WO3 , Na0.15MoO3, K0.3MoO3 were characterized by the termogravimetric-differential- thermal analysis (TG-DTA). Regions of stability of Na0.92WO3 : 20-700°C , of MxMoO3 : 300-500°C were founded. Conclusion about correlation of nonstoichiometry of chemical composition of EOx bronzes and oxides, which making important role in formation of less - common metal bronzes structure.
Keywords: oxide alkali bronzes, tungsten, molybdenum, thermostability, nonstoichiometry, thermal analysis
To the East Donbass agglomeration has developed thematic maps of subsiding soils, indicating their capacity, groundwater levels, surface subsidence above mining, landslide and erosion hazards. Sources of information were the materials of the geological surveys, maps and literature data, and numerical modeling. For the purposes of industrial and civil construction built the final map of the cumulative effects of geological hazards.
Keywords: geological hazard, modeling, geofiltration,subsidence, landslides, erosion, underflooding, agglomeration.
The article deals with the preparation of the leading schools of art of the early twentieth century in Germany and Russia. Determined the reasons for leaving between classical training and subsequent return to the system of art education to the academicism.
Keywords: coloristics, art education, color, professional education
In the article was shown the essence of the concept of "service" from the standpoint of marketing and logistic activities, the service dualism, the assessment of service of marketing and logistic positions. In the article was made an attempt to differentiate service operations to marketing or logistics activities in the aim of improving the management process of customer service and competitiveness of the company
Keywords: service, service management, logistics service, marketing service, service assessment
The especially the functioning of fluid catalytic cracking plant are considered. A mathematical model of a catalytic cracking plant is presented here. Implemented model identification based on experimental data. The predictive controller based on predictive control method for dynamic processes is developed. Effectiveness of the approach is confirmed by the results of catalytic cracking plant simulation.
Keywords: catalytic cracking, modeling, model predictive control, multivariate control system, optimization
This article is devoted to the analytical determination of deflections of beams with corrugated web. The reduced shear modulus which must be considered when determining the components deflection from of the shear strain in the beam with corrugated web is defined. Applying the energy method in the form of the Ritz, the problem of determining deflections with considering of bending strain and shear strain is solved. This article, as an example, is considered simply supported beam on both sides of constant and variable cross-section and are given to the final formulas according with three kinds of loading. The results of the calculation of the numerical examples for the three main shapes of corrugated web are submitted. Numerical results with great accuracy are consistent with calculations based on the finite element method.
Keywords: beams, corrugated web, energy, work, deflection, shear strain
The presented work extends the state-of-art of visualization construction simulations in three dimensions (3D). Classical computer graphics methods can be used to instrument construction models to automatically generate dynamic visualizations of any construction models. The visualization problem of FEM analysis is considered. A description is presented of programs of convertation and visualization of results of finite element method analysis of geodesic domes.
Keywords: simulation, computer graphics, geodesic domes, finite element method, convertation, visualization
Credit availability to construction sector entities determines for thin-capitalized construction firms the possibility of survival during the crisis and of efficient growth during the economic recovery. The main lenders for construction sector entities are commercial creditors (suppliers) and banks. Although their credit policies are similar, debt to commercial creditors dominate in the balance sheets of borrowers, because of customary business practices in construction industry and regulatory distinctions.
Keywords: information asymmetry, agency theory, trade credit
This article describes an algorithm for finding the linear functional quality that describes the order of preference on a set of technical systems. The basic idea, which implements the algorithm is to break the complex solutions of the preference (for many variables) into a number of simple solutions (in pairs of variables), followed by a formal synthesis of the overall solution.
Keywords: The algorithm for finding the linear functional quality of the order of preference on a set of technical systems, formal synthesis, the numerical value of the degree of competence of the individual experts
This paper presents key capital structure determinants of construction companies and their impact on fund raising and financing mix formation in accordance with the conditions of construction activity. It was found that profitability and tangibility have a positive effect on leverage, risk - the negative and the effect of company size, assets growth rate and taxes is ambiguous.
Keywords: capital structure determinants, profitability, risk, taxes, tangibility, construction companies
The article describes the main problems of circuit simulation. The problem of solving ill-conditioned systems of linear algebraic equations (SLAE) of large dimension. The modified algorithm is a linear algebraic solutions. Described a hybrid evolutionary algorithm for solving linear systems based on the proposed modified method. The results of the pilot study and comparison of the algorithm with the algorithms based on the traditional methods for solving linear algebraic equation, which confirm the advantages of the hybrid evolutionary algorithm.
Keywords: Genetic operators, evolutionary algorithm, the system of linear algebraic equations, computer-aided design.
The mathematical model of the potential distribution in the semiconductor surficial region in the presence of deep-lying levels in its forbidden zone which specified by multiple-charge impurity centers has been developed. The simulation results can be used for the width of the space charge region estimation, for the prognostication of the most probable mechanism of the charge carriers transfer in metal-semiconductor structure with multiple-charge deep-lying levels and also for the prognostication of the barrier capacitance value. It can be used in the development of solid-state electronic devices with improved values of some parameters.
Keywords: Poisson’s equation, multiple-charge impurity center, potential distribution, deep-lying levels
This paper is devoted to development of gas sensors air control. It is shown that copper oxides are the promising materials for high sensitive sensors. The CuOx film material was syntheses by means of citrate sol-gel technique. The sensors fabricated on the basis of CuOx film material were sensitive to ammonia gas in the range of 25-150 ppm. Working temperature was determined as 180 °C. Such sensors can be used for work area air control of industrial enterprises.
Keywords: gas-sensitive element, atmospheric air, sensors, copper oxides
Stability of sensors on the basis of inorganic oxide materials is one of the primary goals by working out of atmospheric air control devices. In this work long-term stability of a sensor response on the basis of the SiO2SnOxCuOy material to carbon oxide (II) exposure in a range of concentration 1-100 ppm is studied. It is shown that the sensor response differs high stability and reproducibility. Continuous heating within 21 days to working temperature (350°С) influence its value negligibly.
Keywords: stability of a response, sensor, carbon oxide, material of structure of SiO2SnOxCuOy.