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  • Display of the orthogonal projection of a four-dimensional hypersurface


    Problem research of display the orthogonal projection of four dimensional hypersurface defined by the equation in an implicit form one and two hyperplane. To communicate and bypass hypersurface Discriminants assumes that the hypersurface of the two-parameter family of two-dimensional display received surfaces in five-dimensional space. The analysis of kriminant four dimensional hypersurface orthogonal projection onto the coordinate hyperplane in two coordinate axes. The intersection of three dimensional hypersurfaces axiom (kriminant) defines a two-dimensional surface that is the envelope of the two-parameter family of two-dimensional surfaces. Are the necessary and sufficient conditions of existence of this envelope.
    The results obtained are used to study the Discriminants four-dimensional hypersurface, the display of two-parameter family of spheres in a five-dimensional space.  

    Keywords: a family of surfaces, hypersurface, envelope, the display features, а discriminant.

  • Liquid glass and aqueous solutions of silicates, as a promising basis for technological processes of new nanocomposite materials

    The properties of the water-soluble high-modulus silicate systems: based on alkali metal polysilicates called liquid glass and chain their transformation from lower to higher oligomers, with the subsequent formation of colloidal solutions - silica sol. The methods of preparation, properties and applications of water-soluble high-modulus silicate systems. The possibilities of their use as a binder and modifying agents for various nanostructured composite materials. The examples of promising areas of application of liquid glass and high modulus of aqueous solutions of silicates in construction and industry. In particular show the possibility of using liquid glass and aqueous solutions of silicates in the production of nanostructured silicate polymer. In space engineering for manufacturing water-destructed mandrels used in the manufacture of solid rocket motor casings and pressure vessels 'cocoon' of composite materials by winding. The application of the inorganic sol to obtain a nanocomposite ceramics and monolithic blocks of silicon oxide, which can be used in various fields of modern technology. The possibility of using silica sol as a binder for refractory ultra-lightweight shielding materials used to protect equipment from high impacts. The directions of development of the production of new acid-resistant materials and linings for protection of chemical equipment, parts and components operating in corrosive environments.

    Keywords: Keywords: water glass, silicate polymer concrete, additives, silicates organic bases tetrafurfuriloksisilan, furfural alcohol, nanostructure composite materials, water-soluble silicates, silica sol, sol-gel transition, cured xerogel water-destructed mandr

  • Synthesis and electrochemical properties of LiMn1/3Cr1/3Fe1/3O2 solid solution with the structure of α-NaFeO2

    The solid solution of  LiMn1/3Cr1/3Fe1/3O2 with the structure of α-NaFeO2  isostructural with the widely used LiCoO2  has been synthesized and investigated as a cathode material. Rated voltage of LiMn1/3Cr1/3Fe1/3O2  relative to the lithium is 4 V.  The possibility of charging − discharging the material to a specific capacity of 220-250 mAh/g at currents of C/15-C/50 without phase transformations has been experimentally demonstrated. 

    Keywords: lithium-ion batteries, cathode materials, Delafosse, solid solution, X-ray structural analysis, electrochemical properties

  • Stability analysis of deep loosening slopes.

    The results of calculations on the stability of slope lands treated in a new way. Device intrasoil walls combined with loosened intervals allows prevent subsurface runoff water, which reduces surface erosion slopes, improves the fertility of farmland returns a highly eroded areas in turn, eliminates the wetlands at the foot of the slopes. Established that the stability of the treated soil layer on the slope ample.

    Keywords: stability of sloping land, subsurface walls, soil subsurface runoff, soil erosion, wetlands, deep tillage, moisture saturation slope.

  • Some aspects of finnish language teaching russian as a foreign language and how family in Finland

    Based on the analysis of works of finnish experts shows that learning russian language with learning the finnish language as a foreign supports the development of bilingual identity and language readiness of students. 

    Keywords: russian, finnish, teaching.

  • Technique of optimization of tree cutting process via integrated machine

    The article suggests technique of optimization of tree cutting and skidding process via felling-skidding machines and felling-skidding-processing machines. The realization of this technique will allow reducing of time costs and raising of machine efficiency taking into account accessibility of stand cutting, relief features and technological working conditions.

    Keywords: integrated machine, cutting, tree, timber harvesting, skidding.

  • Local Atomic and Electronic Structure of the Fe dopants in AlN:Fe Nanorods

    Fe-doped AlN nanorods were studied by means of x-ray absorption spectroscopy above the Fe K- and L2,3- edges. Theoretical simulations of the x-ray absorption spectra show that Fe atoms mainly substitute Al. A minor fraction of Fe interstitials or Fe-Al-N ternary alloy can be identified as well. Bader’s AIM analysis predicts that neutral substitutional FeAl defect is in 2+ charge state, though Al in pure AlN is in 3+ charge state.  Fe L2,3 absorption spectra and photoluminescence data indicate the coexistence of Fe2+/Fe3+ in AlN:Fe nanorods so different charge states of substitutional FeAl should co-exist.

    Keywords: diversification of management, production diversification, financial and economic purposes of a diversification, technological purposes of ensuring flexibility of production

  • Long-term monitoring of human respiratory activity

    This article reviews systems of respiratory activity registration in relation to sports medicine. Attention is devoted to the use of miniature accelerometers that record the movement of the chest, as the optimal method for the diagnosis of the respiratory parameters. Other methods are based on piezo-resistive sensors, pressure and airflow sensors, and airways resistance sensors. The authors' developed device based on three-axis accelerometer is proposed. It recognizes episodes of apnea with sufficient accuracy for long-term monitoring. The algorithm of the accelerometer data processing is described. In order to minimize noise impact on the useful signal it is necessary to transform the three-dimensional cloud of accelerometer data into a flat sector. Then the relation of gravity vector deviation angle and the nominal position in time is determined. This presented device due to its ability to transmit data via Bluetooth technology, after appropriate software development for mobile phone and the receiving terminal of medical professional, will be able to organize a simple ergonomic long-term remote monitoring of respiratory activity.

    Keywords: systems of respiratory activity registration, long-term remote monitoring, three-axis accelerometer

  • The computational model thrust bearing with high load-bearing capacity, working on non-Newtonian lubricants with tailored support surface

    The ability to choose the right anti-wear additives [1-6 ] allows you to create lubricants , which are thin layers have different properties than in large volumes. It is commonly assumed that the additives are functioning only in the zone boundary lubrication and are outside the scope of the hydrodynamic theory of lubrication . However, the beneficial effect of additives as indicated in many studies [1-5 ] we have in the " thin layer" of hydrodynamic lubrication .As is well known , lubrication bearings operate on different types of lubricants which are composed of base oil and additive compositions that provide the required functional properties of the oil . Additives polymers with high molecular weight oils impart viscoelastic properties . Analysis of existing studies [ 7-9] on the calculation of bearings running on a viscoelastic lubricant , shows that they do not take into account the dependence of the viscosity and shear modulus of the pressure and temperature, and mode of friction is assumed laminar. It is known [ 10 ] , high-speed bearings operating in turbulent friction , higher pressure and higher temperature, and so the development of methods for calculating the bearings running on a viscoelastic lubricant requires consideration of the above factors.In connection with the above written shall first develop the computational model of thrust bearings running on micropolar lubricant with the viscosity characteristics of the lubricant on the pressure in contrast to the existing theoretical models do not take into account these dependencies (task 1).And then consider the calculation model of extra load -bearing capacity , working on a viscoelastic lubricant for the dependence of its characteristics on the pressure (objective 2).

    Keywords: thrust bearing with the abutment surface adapted, non-Newtonian lubricants

  • Local atomic and electronic structure of nanostructured condensed materials for rechargeable current sources on the basis of V2O5/Fe/LiF nanocomposite within charge-discharge cycle

    In this paper we study of the local atomic and electronic structure of nanostructured condensed material for rechargeable current sources on the basis of 15mas.%V2O5/Fe/LiF nanocomposite within charge-discharge cycle. Principle component analysis (PCA) of the series of Fe K-edge spectra collected during 1 st charge showing the concentrations of the components Fe, FeF2 and V[FeV]O4. We found the changes in the V oxidation state from the analysis of the experimental Fe K- and V K- XANES spectra. Total and partial density of states of components are presented.

    Keywords: nanostructured materials for rechargeable current sources, dynamics of local atomic and electronic structures, XANES, DFT

  • Comparative study of the catalytic activity Pt/C and PtхNi/C materials in the oxygen electroreduction

    The catalytic activity of Pt/C and PtxNi/C electrocatalysts prepared by  borohydride methode was studed. It was established that the specific activity  of fresh prepared Pt3,7Ni/C  catalyst  in oxygen  electroreduction  reaction is higher in compare with Pt/C material. After treatment of Pt3,7Ni/C material in the hot acid  nickel in the surface layers of nanoparticles was dissolved and the composition of nanoparticles was changed to Pt5,6Ni. The electrochemical surface area of the Pt5,6Ni catalyst and specific activity was slightly decreased after corrosion treatment. 

    Keywords: platinum electrocatalysts, corrosion stability of the nanoparticles, fuel cells, X-ray diffraction, borohydride synthesis

  • Development of a universal database structure and properties of chemical compounds to build models "structure-property" based on heuristic algorithms

    The problems of building the architecture and design of the database structure for the storage of the structure of the chemical compounds and their analysis using heuristic algorithms
    Proposed the structure of the database that allows you to store information about the structure of chemical compounds with varying degrees of detail. This approach simplifies forming of the structural descriptors used to build models of "structure-property" based on the genetic algorithms.

    Keywords: database architecture, chemicals, data mining, heuristics

  • UV photodetector based on nanorods and zinc oxide films

    With the use of pulsed laser deposition and carbothermal synthesis а photosensitive structure on the basis of the Schottky barrier Au/ZnO(nanorods)/ZnO(film)/ZnO(nanorods)/Au was obtained. The parameters of the carbothermal method of synthesis of nanorods ZnO were optimized. Under directly applied bias of 7V current sensitivity of luminous flux for this photodetector is observed in the UV and visible regions of the spectrum, and is 0.14 A/W - for 325 nm and 0.18 A/W - to 405 nm, which means that this structure has the ability of potential applications in various fields for the control of UV radiation (for example, for the monitoring of solar UV radiation, control of UV radiation in air and disinfecting water devices).

    Keywords: ZnO nanorods, Schottky barrier, photodetector, photosensitivity

  • Catalyst-free thermal synthesis of ZNO nanocrystals from zinc vapor by low temperature

    ZnO nanorod arrays have been synthesized on silicon wafers by chemical vapor deposition (CVD) technique with different  temperature modes, without metal catalyst.  With this method   vertically aligned ZnO nanostructures  were grown at the quite low temperatures.  Modification of the method allowed to place silicon substrates in areas with different  ratios of concentrations of the molecules in the vapor phase. Photoluminescence spectroscopy and electron microscopy studies have shown that morphologies and optical properties of nanorods depends on different ratios of concentrations of the molecules in the vapor phase.

    Keywords: ZnO nanorods,chemical vapor deposition (CVD), photoluminescence

  • Pulsed laser deposition of ZnO nanostructures

    The arrays of ZnO nanorods were obtained on the sapphire substrates by means of pulsed laser deposition under the high pressure of argon. The conditions of synthesis were optimized, and their influence on the morphology of  ZnO nanostructures were revealed. It is shown that the concentration of oxygen vacancies in ZnO nanorods can be changed by regulation of the synthesis temperature from 850 to 915 °. This process can be controlled by the ratio of intensities of the photoluminescence emission in the visible and ultraviolet regions. So, it allows to create nanostructures for UV photodetectors or chemosensors depending on the temperature choice.

    Keywords: ZnO nanorods, laser deposition, PLD, photoluminescence