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
"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
The paper examines the main approaches to the modeling of scientific and technical progress. Details the conditions and change the model postulates technological structure , its main provisions . Put tasks that are of great interest for scientists involved in the modeling of scientific and technological progress , and for economists who are interested in the practical application of these results . Values of other well-known models of STP . The variants of modernization and the possible synthesis of these approaches to modeling change tehnologichekogo order.
Keywords: scientific and technological progress, advanced technology, changing technological way of practical experience, the elasticity of factor capital
The work in the Internet is impossible without the use of search systems. The quality of the responses to user’s requests to a large extent depends on the keywords. However, due to some circumstances the user is not able to accurately enough to formulate a request and the number of received responses is great. In these situations, additional feature relevant answers selection can be text documents belonging to a particular implicit group. Implicitness group is shown in the fact that the text belongs to it is determined not by direct comparison with the reference (key) words, but by matching the semantic features, the wording of which is absent in the search text. Implementation of text classification can be made on the basis of the frequency characteristics of N-grams. The purpose of the work is to assess the possibility of using the frequency characteristics of N-gram of the websites text fragments to improve search engine based on a study of their information content. In this work designed a method based on the selection of informative indicators of N-gram with low computational requirements and with application of the correlation analysis. Based on its application has been shown that the frequency characteristics of N-grams have sufficient information content to improve search engines. The developed method has many common with systems of writing, because it relies not only on the alphabetic systems.
Keywords: N-gram, request, semantic features, search engine
In the article was discusses the problem of assessing the effectiveness of marketing research with the help of different methods; was done an attempt to identify the approaches to determining the effectiveness of marketing research based on their goals. Also was developed the formulas for quantitative evaluation of the effectiveness of marketing research.
Keywords: the efficiency of marketing research, assessment of marketing researches, economic efficiency of marketing research
The article deals with the question of the influence of monocentric spatial organization on the development of the city of Rostov -on-Don , and as determined by the solutions to the problems connected with it . The relevance lies in the fact that describes the current status of the spatial organization of Rostov-on - Don in the context of the global trend of de-urbanization . The concept of environmental focus in determining the spatial organization of the urban environment. The main idea of which - to ensure the harmonious coexistence of the city and the environment, humans and nature , and the main problems of the current situation of urban structure of the city Rostov- on-Don. The important is to identify solutions to problems related to the monocentric organization of the city, as a first step - the creation of a suburban low-rise building with a separate infrastructure
Keywords: Spatial organization, the development of the urban structure, Seachange, polycentric
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 possibilities of waveguide elements realization in the structure of multilayered integrated chips of centimeter and millimeter ranges with SIW (Substrate Integrated Waveguide)-technology application are considered. The approaches allowing effectively using in new structures the algorithms and techniques of the electrodynamic analysis and synthesis of passive devices on classical all-metal waveguides are offered. Advantages of use in SIW structure the waveguides of complex cross-section are considered on the example of the microwave band-pass filter.
Keywords: A.A. Gadzieva, V.V. Zemlyakov, S.V. Krutiev
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 methods of forming the program of technical and economic feasibility of reconstruction. The program is based on the technical and economic calculations which justify the need for its development. It is important to take into account the technical and economic indices which provide a minimal amount of construction works. During the development of technical and economic parameters, it is necessary to take into account the organization of construction, the terms of energy saving, heating, water supply, drainage and industrial waste water, human resources, the environment, the effectiveness of capital investments. All questions are considered for the perspective of the development of science and technology.
Keywords: site renovation, technical-and-economic indexes
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 article presents the new technologies and design tools for опиливания of machine parts. A number of new technical solutions in the field of innovative Metalworking tool for опиливания parts of machines, with a complex of technical and economic advantages over existing analogues. Shows the five variants of constructions and technologies for the production of files and надфилей, based on the use of hard coating. New tools are characterized by a low-cost, low labour-intensiveness of manufacturing and high performance.
Keywords: tribology, the filing of a painful, spraying, carbide coatings, wear, self-sharpening, reversible cutting plates
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
In this work researches of structural and electrophysical properties of ferroelectric films of lead zirconate titanate (PZT) which afterwards is planned to apply in hybrid sensor systems are done. Values of capacities of the received samples are in the range from 200 to 1100 pF, the range of thickness of the received films is 300-1000 nanometers. X-ray analysis showed direct dependence of the quantitative maintenance of crystalline PZT in film structure from partial pressure of oxygen in the camera. By results of research the range of polarization of samples are in the range 0,06 – 2,2 µC/cm2, and values of calculated piezoelectric modules are in the range 0,04*10-12 – 13,3*10-12 C/N.
Keywords: sensors, segnetoelektric films, touch systems, piezoelectric modules.
The integrated sensor LR-type on the basis of carbon nanotube is described. Are offered a method of processing of the sensor signals. Results of modelling are represented.
Keywords: Еlement base, microelectromechanical system, design, sensor, gyroscope, accelerometer.