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Search Results: 1 - 10 of 171354 matches for " Yu.O. Kulyk "
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Porous structure of carbon-based materials studied by means of X-ray small angle scattering method
B.Ya. Venhryn,I.I. Grygorchak,Yu.O. Kulyk,S.I. Mudry
Optica Applicata , 2008,
Abstract: The porous structure of carbon-graphite materials: styrene-divinylbenzene copolymer (SBC) and fruit stones (FS) has been studied by means of X-ray small angle scattering method. The angular dependences of scattered intensities have been obtained and analyzed by means of the Guinier method. The main parameters of porous structure have been determined (inertia radius, pore size distribution functions, specific surface areas).
Changes in the fractal and electronic structures of activated carbons produced by ultrasonic radiation and the effect on their performance in supercapacitors
B.Ya. Venhryn,I.I. Grygorchak,Z.A. Stotsko,Yu.O. Kulyk
Archives of Materials Science and Engineering , 2012,
Abstract: Purpose: Effect of ultrasonic irradiation on change of electron structure as well as fractal one of activated carbons and motivation that these changes are most responsible for the improvement of functional parameters in supercapacitors, were the aim of this paper.Design/methodology/approach: Experimental studies were carried out by means of impedance spectroscopy, cyclic voltammetry, X-Ray diffraction, small angle X-Ray diffraction, X-Ray photoelectron spectroscopy, IR-spectroscopy, Micro-Raman spectroscopy and galvanostatic cycling methods.Findings: Ultrasonic modification of carbon is effective method to increase the specific capacitance as well as power of carbon-based supercapacitors. Changes of parameters of double electric layer are tightly related with change of fractal dimension and allow increasing the percolate mobility of charge carries.Research limitations/implications: This research is a complete and accomplished work.Practical implications: Carbon materials, modified by ultrasonic irradiation, can be used as promising electrode materials in energy storage devices of new generation.Originality/value: This work is of urgent importance for studying of physical and chemical processes in energy storage systems. It is shown that method of ultrasonic irradiation is highly effective for modification of carbon-based materials as electrodes in supercapacitors.
Reparative osteogenesis at hyperhomocysteinemia (experimental study)
Bezsmertnyi Yu.O.
Морфолог?я , 2013,
Abstract: On the model of fracture of the femur studied peculiarities of reparative osteogenesis at hyperhomocysteinemia and demonstrated the possibility of its correction drugs with hypohomocysteinemia effect. It is established, that hyperhomo-cysteinemia induces dysregulation of reparative osteogenesis with the formation of large areas of necrosis and degeneration at the fracture site. Metabolic correction of hyperhomocysteinemia preparations with hypohomocystinemic action (decamevitum, glutarginum) optimizes for reparative regeneration of the fracture.
Early thyroid gland dysfunction and biorhythmic activity disturbance in patients with cardiovascular pathology and atrial fibrillation
Baurina Yu.O.,Mayskova Е.А.,Shvarts Yu.G.
Saratov Journal of Medical Scientific Research , 2012,
Abstract: The review deals with the problem of combined pathology of the thyroid gland and cardiovascular system, the state of thyroid homeostasis in atrial fibrillation. The main mechanisms of action of thyroid hormones on the heart and blood vessels, particularly changes in the cardiovascular system with hypo-or hyperthyroidism; the possibility of substitution therapy in subclinical disease have been presented in the article. Characteristics of daily rhythmic activity of thyroid gland in normal and various pathological conditions with persistent and paroxysmal atrial fibrillation have been considered.
Self-Assembly of Low-Dimensional 3D Titanium Systems During Quasi-Equilibrium Steady-State Condensation
O.А. Mokrenko,Yu.O. Kosminska,V.I. Perekrestov
Journal of Nano- and Electronic Physics , 2011,
Abstract: Structure formation mechanisms of low-dimensional porous systems are explained on the ground of different growth rates at local condensate areas and partial coalescence of the structural fragments. By means of scanning and transmission electron microscopy the formation mechanisms of porous Ti condensates on glass and KCl cleaved facets are studied. It is shown by the example of self-assembly of porous Ti layers that the factors underlying such process are self-organization of time-constant critically low effective supersaturation and continuous sequence of interdependent structure and morphology changes of the growth surface that cause the appearance of active centers for attaching adatoms.
Modeling Diffusion Interaction in the bi-Phase Systems with Using Different Types of the Effective Kinetic Coefficients
L.I. Gladka,Yu.O. Lyashenko
Journal of Nano- and Electronic Physics , 2012,
Abstract: The analysis of basic and combined models for calculation of effective kinetic coefficients required to describe diffusion processes in two-phase heterogeneous environments is conducted. For a transition zone that grows between two interacting diffusion phases was built a new model of effective medium. In this model the effective kinetic coefficient depends on the kinetic coefficients in each of the phases, volumetric particle phases and additional free parameter, which generally characterizes the type of structure of a bi-phase zone. It is shown that the combined model is constructed to describe the percolation behavior of effective medium. The phenomenological approach describes the formation and development of bi-phase zones in ternary systems which including streams through both phases and the analysis of the impact of the model on the resulting effective medium diffusion zone.
Hybrid Hydrogel Materials with Incorporated Nanoparticles
Samchenko Yu.M.,Kryklia S.O.,Poltoratska T.P.,Isheikina Yu.O.
Proceedings of the International Conference Nanomaterials : Applications and Properties , 2013,
Abstract: Synthesis and physico-chemical studies of new promising hybrid hydrogels based on polyvinyl alcohol (PVA) acetales and copolymer hydrogels based on vynil monomers have been studied. Acrylamide and Acrylnitrile were used as some of components that carry various fillers . Sponge acetales of polyvinyl alcohol were used as enforcing net. The synthesized composites demonstrated high strength as compared to standard hydrogels- Yung-module varied in the range of 80 to 300 kPa depending on the extent of PVA acetale matrix filling with hydrogel component. The materials showed high sorbability to water and water solutions. Study of swelling kinetics as compared to solvents of various nature (water, ethanol, sunflower oil ) was carried out.
Cardiac biopotentials influence on central nervous system functioning: first steps in hypothesis verification
Shvarts Yu.G.,Cherkasova S.A.,Kondal'skaya Yu.O.
Saratov Journal of Medical Scientific Research , 2012,
Abstract: The research goal is to verify the hypothesis on influence of cardiac biopotentials on central nervous system. Materials: 20 healthy individuals aged 18-26 years old have been participated in the investigations. Two groups composed of 10 patients each have been formed. Double increase in heart biopotentials by means of artificial impulse insertion between natural cardiac contractions has been modeled. Artificial impulses have been similar to unaffected ones, produced in a normal heart work. Additional impulses have been generated using external pacemaker and have been linked up with electrodes on the chest. They have been synchronized with the heart rhythm and located in-between R waves. The duration of those impulses has been fully matched to ventricular complex. Their amplitude has been adjusted individually depending on the height of R wave. Nervous system mobility has been used as the indicator reflecting the central nervous system functioning. Degree of mobility has been defined on the basis of tapping test results. The test has been repeated at specific intervals. Groups have been exposed to two adverse testing modes. Additional impulses have been conducted to the patients of group I within an hour over a period of the first and the third 15-minute intervals and to the patients of group II over a period of the second and the fourth 15-minute intervals. In the middle and in the end of each time interval tapping test has been carried out. After preliminary analysis two other modes of stimulation have been tested. The stimulation has been performed within the 40-minute course: over a period of the first 20-minute interval and vice versa. Results: Detailed evaluation has revealed that short-time increase of nervous processes has been checked in combination with decrease in their stability. Conclusion: The data obtained have shown that there is possible influence on central nervous system functioning. The article ends with prospects of further investigation.
Structure and electroconductivity of the nanocrystalline CoNi thin film alloys
V.B. Loboda,V.O. Kravchenko,Yu.O. Shkurdoda
Journal of Nano- and Electronic Physics , 2009,
Abstract: Structure, phase composition and electroconductivity of nanocrystalline CoNi thin film alloys are investigated. During the I-st cycle of thermal stabilization the grain size increases from approximately 5 nm to 110-200 nm. Films with Co content less than 70 mass % have the single-phase composition with the fcc-lattice. Increase in the lattice parameter, which can be described by the Vegard's rule, is observed with the growth of Co concentration. At Co content more than 75 mass % the annealed films have the two-phase fcc-hcp composition. Quadratic temperature dependence of the resistivity, which is also observed for the single-layer films of pure ferromagnetic metals, is inherent to the films of a given alloy. Using analysis of the size dependences of electroconductivity the concentration dependence of the resistivity is plotted.
Structure and magnetoresistive properties of three-layer film systems CoNi/Ag(Cu)/FeNi
V.B. Loboda,V.O. Kravchenko,Yu.O. Shkurdoda
Journal of Nano- and Electronic Physics , 2009,
Abstract: We present the investigation results of the structure-phase state and magnetoresistive properties (anisotropic and giant magnetoresistances) of three-layer nanocrystalline film systems CoNi/Ag(Cu)/FeNi in conditions of ultrahigh oil-free vacuum.
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