PCSS, V.14, №4, 2013

Abstracts

B.M. Ruvinskii¹, M.A. Ruvinskii²

On the Nonlinear ac Conductivity in Doped Graphene

¹Ivano-Frankivsk National Technical University of Oil and Gas, 15, Carpatska Str., Ivano-Frankivsk, 76000, Ukraine, bruvinsky@gmail.com
² Vasyl Stefanyk Precarpathian National University, 57 Shevchenko Str., Ivano-Frankivsk, 76000, Ukraine

The interband and intraband conductivities of doped graphene were theoretically investigated beyond the linear response. The new dependences of induced currents on frequency and amplitude of external electric field, the graphene temperature and chemical potential were determined for sufficiently strong electric fields in the resonant approximation. Particularly, the saturation of induced currents and the non-linear increase of optical transparency with wave intensity growth were obtained for arbitrary temperatures and doped situation. As contrasted to increase for the interband transitions at fixed intensity, the transmission coefficient of intraband mechanism decreases with rise of the chemical potential and temperature.
Keywords: doped graphene, ac conductivity, post-linear response, resonant interaction.

М.А. Ruvinskii¹, B.М. Ruvinskii²

On the Hypersonic Absorption in Straight-line Graphene Ribbons

¹Vasyl Stefanyk Precarpathian National University 57 Shevchenko str., Ivano-Frankivsk, 76000, Ukraine
²Ivano-Frankivsk National Technical University of Oil and Gas 15 Karpatska str., Ivano-Frankivsk, 76000, Ukraine bruvinsky@gmail.com

We have investigated the intraband and interband electron mechanisms of hypersonic absorption in straight-line graphene ribbons. The absorption coefficients of confined hypersonic phonons, taking into account the screening of deformative electron-phonon interaction with charge carriers and the dispersion laws of Dirac electron states, have been determined.
Keywords: straight-line graphene wire, confined acoustic phonons, intraband and interband electron transitions, hypersonic absorption.

Z.P. Chornij¹, I.B. Pirko², V.M. Salapak¹, N.V. Djachuk¹

Color Centers in CaF₂-Na and CaF₂-Lі Crystals. II. Results of Experimental Research

¹Department of Physics, National Forestry University of Ukraine, 105 Gen. Chuprynky St., Lviv, 79057, Ukraine
²Department of Computer Engineering and Modeling Processes, National Forestry University of Ukraine, 103 Gen. Chuprynky St., Lviv, 79057, Ukraine, e-mail:pirko1966@mail.ru

In the one-dimensional model of ionic crystals the parameters of the radiation sensitivity of the crystals fluorites doped with alkali metal: w1 - probability of formation of color centers in the crystal lattice; w2 – vysvitlyuvalnoyi probability of radiation. Th e adsorbed concentration of color centers in the crystal at low temperatures (T < 200 K) C1 = ½ ( w1 / (w1 + w2), and at temperatures T > 250 K C2 = ¼ ( C, where C – concentration of impurities in the crystal. The dependence of the concentration of color centers on the content of alloying elements in the crystal and the structure of color centers. The calculations of fluorite crystals radiation parameters were conducted in the frame work of ionic crystal one dimensional model. The theoretical results were compared with experimental data.
Keywords: fluorite, impurity-vacancy dipoles, color centers, thermally depolarization, one-dimensional model.

Т.О. Parashchuk

Heat Capacity and Debye Temperature of ZnTe, ZnSe, ZnS Crystals

Vasyl Stefanyk PreCarpathian National University 57, Shevchenko Str., 76018, Ivano-Frankivsk, Ukraine, E-mail:taras-parashchuk@i.ua

Based on the results of ab initio quantum-chemical calculations of the crystal structure of molecular clusters the temperature dependence of the specific heat of ZnTe, ZnSe, ZnS crystals at constant volume CV have been defined. Computer calculations of thermodynamic parameters was carried out by density functional theory (DFT), using the B3LYP valence hybrid basic set. Also the analytical expressions of presented temperature dependences of the thermodynamic parameters have been gotten, and based on them , using the mathematical package Maple 14, the Debye temperature for these materials have been calculated.
Keywords: cluster model, quantum chemistry, zinc sulfide, thermodynamic parameters.

D.M. Zayachuk¹, O.S. Ilyina¹, V.I. Mikityuk², V.V. Shlemkevych², D. Kaczorowski³, and A. Csik⁴

Small Eu Complexes into the Bulk and the Surface Layers of PbTe:Eu Crystals Doped With Different Impurity Concentration

¹Lviv Polytechnic National University, 12 Bandera St, Lviv, Ukraine, e-mail:zayachuk@polynet.lviv.ua
²Yuri Fedkovich Chernivtsy National University, 2 Kotsyubynsky St, Chernivtsy, Ukraine
³Institute of Low Temperature and Structure Research, Polish Academy of Sciences, 50-950 Wroclaw 2, P. O. Box 1410, Poland
⁴Institute for Nuclear Research, Hungarian Academy of Sciences, H-4026 Debrecen, Bem ter 18/C Hungary

We present the results of the first experimental evidence of inverse distribution of small magnetic complexes of Eu impurity along the bulk axis and the lateral surfaces of the PbTe:Eu crystal ingots grown from doped melts with significantly different initial concentrations of doping impurity Nint(Eu) in the melt. If the Eu concentration is high enough, that the doping impurity enters into the bulk of doped ingot during the process of its growth (Nint(Eu) = 1•1020 cm-3), the mainly small complexes of Eu are formed in the beginning of the ingot and probability of their formation decreases towards the end of ingot. If the Eu concentration is low enough, that the doping impurity is pushed out onto the surface of doped ingot during its growth (Nint(Eu) = 1•1019 cm-3), probability of the complex formation is minimal in the beginning of ingot and increases towards the ingot’s end. An eventual role of the background impurity of Oxygen in formation of the revealed peculiarities of Eu doping impurity distributions in PbTe:Eu crystals is discussed.
Keywords: IV-VI semiconductors, crystals, impurities, doping, rare earth elements, magnetization, magnetic susceptibility

Z.D. Kovalyuk¹, V.B. Boledzyuk¹, Z.R. Kudrynskyi¹, A.D. Shevchenko²

Ferromagnetism in Cobalt-Intercalated In₂Se₃ Layered Crystals

¹Frantsevich Institute for Problems of Materials Science of National Academy of Sciences of Ukraine, Chernivtsi Branch, str. Iryny Vilde 5, 58001 Chernivtsi, Ukraine, e-mail:kudrynskyi@gmail.com
²Kurdyumov Institute for Metal Physics of National Academy of Sciences of Ukraine, pr. Acad. Vernadsky, 36, Kyiv-142, 03680, Ukraine

We report on the impact of cobalt intercalation on properties of In2Se3 layered crystals. It is shown that electrochemical intercalation of Co atoms into the In2Se3 layered crystals does not cause any changes in structural type of the crystals and is accompanied by a decrease in the lattice constant in the direction perpendicular to the base plane. In the case of the Co0.15In2Se3 intercalation compound, obtained by intercalation in constant magnetic field, we manifested ferromagnetic properties at room temperature. The dependence of magnetic moment on magnetic field strength has a shape of hysteresis loop. This dependence was not observed in the case of Co intercalation into In2Se3 without magnetic field. Keywords: In2Se3, layered crystals, cobalt, intercalation, ferromagnetism.

B.K. Ostafiychuk¹, S.L. Revo², М.М. Kuzyshyn¹, I.M. Budzulyak¹, B.I. Rachiy¹

Influence of Degree of Compression on the Electrical Conductivity of the Composite Material

¹Vasyl Stefanyk Precarpathian National University,57 Shevchenko Street Ivano-Frankivsk, 76025, Ukraine, bogdan_rachiy@ukr.net
²Kyiv National Taras Shevchenko University, 64 Volodymyrska Street, Kyiv, 01601, Ukraine, revo@univ.kiev.ua,

In this article are presented the results of researching of composite materials (CM) nanoporous carbon (NPC) - thermally expanded graphite (TEG) their electrical and physical properties depending on the degree of compaction. It was found out that the electrical conductivity of CM depends on the packing density and the TEG particle size. In particular, for samples of TEG with no equal particle size greater than the size of the NPC particles (> 315 microns) observed a sharp decrease of the electrical conductivity of the CM with increasing degree of compaction, and for samples with TEG particle sizes compared with a NPC particle size and their approximation to the identical morphology, value of electrical conductivity was increasing with increasing degree of compaction.
Keywords: nanoporous carbon, thermally expanded graphite, composite material, degree of compaction, density, electrical conductivity.

O.B. Piven’¹, O.B. Piven’¹, Yu.M. Lopatkin²

Research Herschel of Laser Effect in a Constant Electric Field

¹Cherkasy State Technological University, Cherkasy, Ukrainee-mail:abpiven@ukr.net
²Sumy State University, Sumy, Ukraine e-mail:yu_lopatkin@ukr.net

For the first time it was found that the simultaneous action of the constant electric field and IR-radiation of laser causes the transition of the amorphous silver to the crystalline one with forming of the new center of the latent image at the surface of microcrystals of AgBr. The quantity of absorbed energy of the laser IR-radiation influences at the crystallization of amorphous silver.
Keywords: Laser Effect, Microcrystal of AgBr, Electric Field, Crystallization of Amorphous Silver.

A.I. Savchuk, I.D. Stolyarchuk, O.A. Shporta, V.I. Tkachuk

Optical and Magneto-Optical Properties of Pb1-xMеxI2 (Me: Mn, Fe) Semimagnetic Semiconductor Nanocrystals

Yuriy Fed’kovych Chernivtsi National University, 2 Kotsubynskiy str, 58012, Chernivtsi, Ukraine, e-mail:a.savchuk@chnu.edu.ua

Nanocrystals of Pb1-xMеxI2 (Me: Mn, Fe) have been studied by optical absorption, photoluminescence and electron paramagneric resonance. The exciton structure of absorption spectra of nanoparticles exhibit blue shift due to quantum confinement effect. In photoluminescence spectra of nanoparticles two main peaks were revealed, which are attributed to the band-edge transitions and defects states. The substitutional incorporation of transitions metal ions at lead sites is finding in EPR studies. Isolated as well as interacting Fe3+ ions are exhibited in EPR spectra of Pb1-xFexI2 nanocrystals.
Keyword: semimagnetic semiconductor, nanocrystal, nanoparticle, absorption, photoluminescence, electron paramagnetic resonance.

N.I. Nagirna¹, V.I. Mandzyuk¹, R.P. Lisovskуу², Yu.O. Kulyk³

The Structure, Morphology and Electrochemical Properties of Chemically Washed Porous Carbon Materials

¹Vasyl Stefanyk Precarpathian National University, 57 Shevchenko Str., Ivano-Frankivsk, 76018, Ukraine
²G.V. Kurdyumov Institute for Metal Physics of the NASU, 36 Academician Vernadsky blvd., Kyiv, 03680, Ukraine
³Ivan Franko National University, 8 Kyrylo and Mefodiy Str., Lviv, 79005, Ukraine

The effect of chemical treatment of porous carbon material (PCM) on its structure, morphology and electrochemical parameters it is explored in work by the methods of small-angle X-ray scattering, low- temperature porometry, galvanostatic discharge, cyclic voltamperometry and galvanostatic intermittent titration technique. It is set, that chemical treatment of PCM in salt, hydrofluoric and nitric acids result in considerable reduction of specific surface and pore volume and increase of their sizes comparatively with initial material. It is shown, that the indicated changes predetermine also reduction of specific energy parameters of lithium power sources on the PCM basis, electrochemical introduction of lithium ions in which has an irreversible character. The coefficient of the electro-stimulated diffusion of lithium ions in PCM is calculated.
Keywords: porous carbon material, chemical treatment, small-angle X-ray scattering, low-temperature porometry, lithium ions electrochemical insertion.

A.N. Ponyavina, E.E. Tselesh, A.D. Zamkovets

Optical Properties of Planar Densely-Packed Plasmonic Nanocomposites

Institute of Physics, National Academy of Sciences of Belarus, Nezavisimosti Ave., 68, Minsk, 220072; e-mail:a.zamkovets@dragon.bas-net.by

For planar nanocomposites Ag-LiF and Ag-KCl which were fabricated by the thermal vacuum evaporation and characterized by a high volume part of a metal phase (p = 0,4 - 0,8), the concentration features of the surface plasmon absorption band were established and analyzed. Based on the probabilistic approach to the description of a nanocomposite structure, the new combined model of the effective medium is proposed.
Keywords: optical spectra, plasmonic nanocomposites, silver nanoparticles, effective medium approximation.

A.I. Mostovyi¹, V.V. Brus^1,2, P.D. Maryanchuk¹, O.A. Parfenyuk¹

Physical Properties of TiO₂ and TiO₂:Mn Thin Films

¹Yuriy Fedkovych Chernivtsi National University, 2 Kotsybynsky str., 58012, Chernivtsi, Ukraine, e-mail:mostovysya@mail.ru
²Helmholtz-Zentrum Berlin für Materialien und Energie, D-12489 Berlin, Germany

The envelope method was employed to determine optical constants of TiO2 and TiO2:Mn thin films deposited by electron-beam evaporation in vacuum. The effect of thermal treatment on the optical and electrical properties of the thin films was investigated.
Keywords: TiO2, optical properties, electrical properties, doping, envelope method.

Y.P. Saliy, D.M. Freik, L.Yo. Mezylovska, I.S. Bylina, I.M. Freik

Orientation Aspect and Simple Crystallographic form Nanostructures in Vapor-Phase Condensates PbTe: Sb on Ceramics

Vasyl Stefanyk Precarpathian National University, 57, Shevchenko Str., Ivano-Frankivsk, 76000, Ukraine, Е-mail: freik@pu.if.ua

Lead telluride (PbTe) is an advanced semiconductive material in manufacturing optoelectronics devices related to infrared spectrum area, as well as in termoelectronics of medium frequency temperature (500-850) K. Vapor-phase nanostructures on glass ceramics lining have been received from vapor-phase procedure due to open evaporation in vacuum environment ahead of obtaining synthesized compound PbTe:Sb that contains 0.25 at% in different time τ = (15-240) с and temperatures Тs=(420-520) К deposition, according to evaporation temperature Тe = 970 К. The results of research orientation processes of structure formation in the vapor-phase condensates PbTe: Sb / Sital obtained by open evaporation under vacuum at deposition temperatures Ts = (420-520) К and deposition time τ = (15-240) s. Found that on the surface of Sital are formed individual nanoobjects up to 300 nm, which are formed by the crystallographic structure of combinations of faces {100} and {110} crystal structure of NaCl and presented their hnomostereohrafic projections for our case. Defined angles between the normal to the face of nanostructures, which are 45 º, 60 º, 90 º, 120 º and 135 º. The features attributed to crystalline forms electrically neutral state crystallographic planes and the nature of Sital.
Keywords: nanostructures, Lead Telluride, crystalline form, the polar and azimuthal angles.

V.Yu. Loya¹ , M.I. Kozak², A.M. Solomon¹, I.I. Petrichinez³, V.M. Krasilinetz¹

Production AND Studies OF THE Vitreous As2S3 – Based Thin - Film

¹Institute of Electron Physics, Ukr. Nat. Acad. Sci., Uzhgorod, 88000, Ukraine
²Uzhhorod National University, Uzhgorod, 88000, Ukraine 3Institute of Materials Research, Slovak Academy of Sciences, Kosice, 04001, Slovak Republic

Interference transmission spectra of the As2S3 – based thin-film structures and the influence of X-ray radiation on them have been shiclied and the refraction index has been found. The As2S3 – based thin-film structures deposited onto the KCl cleavages have also been shiclied using the scanning electron microscope technigue and the point EDS analysis. The results obtained indicate formation of the amorphous structure with the inclusion of nano-structure inhomogeneities.

R.R. Romanyuk^1,2

Peculiarities of the Energy Gap of Amorphous GeSe Films with Impurities of Bi

¹Western Scientific Centre, 4, Mateyko Str., Lviv, 79007, Ukraine, е-mail: rrr_roman@rambler.ru
²Ivan Franko L'viv National University, 8, Kyryl and Mephodiy Str., Lviv, 79005, Ukraine

The influence of Bi additions on the photoelectrical and optical properties of amorphous (GeSe)1-хBiх films (0(х(0.15) has been investigated. Bi impurities lead to changes of the electron-defect subsystem of condensates. The energy location of localized states in energy gap of amorphous (GeSe)1-хBiх films was calculated. The main topological reactions of defects centres formation were proposed as well as the model of transformation of energy gap under adding Bi. Changes of the physical properties are explained in the framework of the heterogeneous structure of the condensates and defect states in the mobility gap.
Keywords: GeSe, Bi, amorphous films, localized states.

M.F. Bulanyi, O.V. Kovalenko, A.R. Omelchuk, K.Yu. Polozov, O.V. Skuratovska

Receiving ZnO Films, Fused on alternative substrates CVD and MOCVD Methods

Oles’ Gonchar Dnipropetrovsk National university, Ukraine e-mail:koval@mail.dsu.dp.ua

The paper analyzes the physical properties of the films ZnO grown on GaAs (100) substates by CVD at T = 350 °C in a flow of gas mixture of air: nitrogen = 5 : 1, and films of ZnO grown on ceramic substrates by MOCVD at T = 300 °C in in a flow of gas mixture of argon: oxygen = 9 : 1. The thickness of the ZnO films was ~ 1 µm. In the PL spectra of samples grown we observed UV PL band with a maximum at λmax = 380 – 400 nm, which is associated with the radiative recombination of electrons and holes localized in shallow donor and acceptor levels. The wide PL band with λmax = 570 – 580 nm and λmax = 500 – 510 nm for films ZnO grown by CVD and MOCVD, respectively, most likely due to various structural defects of zinc oxide. Among these defects are most likely oxygen vacancies and interstitial zinc. Red PL band with λmax = 670 nm can be associated with surface dislocation, the presence of uncontrolled impurities of lithium and iron, as well as interstitial zinc. Synthesized ZnO films had a polycrystalline structure with a grain size of 40 to 60 nm (method CVD) and from 90 to 110 nm (method MOCVD), in turn, grains have a hexagonal structure with lattice parameters: a = 3,2811 Å; c = 5,2066 Å with a low degree of microstrain: M = 1,09 • 10-3 %.

D.M. Freik¹, V.V. Moklyak², B.S. Dzundza¹, Ya.S. Yavorskyy¹, O.B. Kostyuk¹, O.M. Matkivskyy¹

Transport Phenomena in the Vapor-Phase Condensates PbTe-Sb2Te3 on Sital

1Vasyl Stefanyk PreCarpathian National University 57, Shevchenko Str., Ivano-Frankivsk, 76025, Ukraine
²Instytut Metal Physics H.V.Kurdyumova NAS Ukraine, Academician Vernadsky Avenue 36, Kyiv, 03680, Ukraine

Dependence of the structural characteristics and electrical properties of thin films of solid solutions PbTe-Sb2Te3 warehouses 1,3,5 ml. % Sb2Te3, deposited in an open vacuum on the sital substrates on their thickness d = (0,2-2) microns were studied. Effective mean free path λ of charge carriers and installed the dominant mechanism of scattering were definitely. Within the two-layer Petritz model made assessment of the extent of thermoelectric parameters of surface layers. Found that the condensate has a stable n-type conductivity and there is diffuse scattering on the surface, which leads to a significant decrease in relation to the volume of a film magnitude of mobility (μs), conductivity (σs), and increasing the Seebeck coefficient (Ss). The results are explained by the influence of atmospheric oxygen acceptor and throttling carriers for potential barrier intergrain limits Keywords: film of solid solution PbTe-Sb2Te3, thermoelectric properties, scattering mechanisms.

I.R. Iatsunskyi, V.А. Smyntyna, М.М. Pavlenko, О.V. Sviridova, О.А. Rimashevskiy

Morphological Features of Nanosilicon Fabricated by Metal – Assisted Chemical Etching

Odessa I.I. Mechnikov National University, Department of Experimental Physics, 65023, Ukraine, Odessa, Pastera str. 42, yatsunskiy@gmail.com

In this work the mechanisms of nanosilicon formation method by metal-assisted chemical etching are investigated. The dependence of the properties and topology of the porous surface from the proportion of etchant and oxidant in solution is demonstrated.
Keywords: nanosilicon, metal-assisted chemical etching.

O. Kondrat¹, N. Popovych¹, N. Golomb¹, O. Petrachenkov¹, V. Lyamayev², N. Tsud^2,3, V. Mitsa¹

Self-Organization Processes in As40Se60 Thin Film Nanolayers Stored Under Ambient Conditions and Under Laser Irradiation

¹Instytut Physics and Chemistry of Solids, Uzhgorod National University, Ukraine
²Synhrotron Elettra, Area Science Park, Basovizza (Trieste), Italy
³Charles University, Faculty of Mathematics and Physics, Department of Surface and Plasma Science,Prague, Czech Republic

Near order structure of the surface nanolayers of the thin amorphous films a-As40Se60 under ambient conditions and its changes under the influence of near bandgap laser illumination, investigated by X-ray photoelectron spectroscopy. The shape and energy position of the photoemission peaks of As 3d and Se 3d in amorphous and laser-irradiated a-As40Se60 films were analyzed. Identified and described the differences in the intensity peak components, stimulated by laser irradiation. The estimated relative contributions of As and Se atoms in the As 3d and Se 3d spectra, their structural nature and composition of the surface nanolayers calculated. The atomic model of the stimulated self-organization processes in As40Se60 thin film surface nanolayers is proposed.
Keywords: X-ray photoelectron spectroscopy, amorphous film, laser irradiation, structural units.

H.O. Sirenko, L.M. Soltys

Physico-Chemistry of Phenomenon of Selective Transfer of Copper in the Dynamic Contact of Solids (Review)

Vasyl Stefanyk’ Precarpathian National University, 57, Shevchenko Str., Ivano-Frankivsk, 76018, Ukraine, e-mail:orijant@gmail.com

The main factors that determine the friction and wear of the contacting solids and methods to increase their antifriction and wear resistance have been reviewed. Among them became a prominent place phenomenon of selective transfer of metals, mainly copper, in the dynamic contact of two surfaces. The types of arbitrarily appearance of systems of autocompensation processes of wear and reducing friction in selective transfer of metal have been shown. Mechanisms of formation of protective film on friction surfaces during lubrication by glycerol in the presence of atoms of copper and copper compounds have been analyzed.
Keywords: selective transfer of copper, protective film, friction, wear, dynamic contact.

A.A. Kravchenko, E.M. Demianenko, A.G. Grebenyuk, V.V. Lobanov

Quantum Chemical Investigations on the Сationic Form of Silanol Groups on Silica Surface

Chuiko Institute of Surface Chemistry of National Academy of Sciences of Ukraine, 03164, 17 General Naumov Str., Kyiv, Ukraine, e-mail:kravchenkoandrew7@gmail.com

A quantum chemical analysis of the structure of HF, HCl and HBr hydrated complexes on the silica surface has been carried out by means of Density Functional Theory method with use of extended basis set (6-31++G**). Dissociation constants of the cationic form of a silanol group have been calculated for the complexes with halogen anions of different nature.

M.D. Raransky, V.N. Balazyuk, M.I. Melnyk, I.G. Kurek, O.M. Gorda, M.M. Gunko

Chemical Bond, Anisotropy and Structural Stability of Single Crystals

Yu. Fedkovych Chernivtsi National University, 2, Kotsybinsky Str., 50012 Chernivtsi, Ukraine, (0372)-54-44-00, e–mail: ftt2010@bigmir.net

The determination of the nature of chemical bonding in crystals with diamond and sphalerite type of lattice by acoustic method is proposed. It is shown that forming chemical bond in the binary compounds is accompanied by a corresponding alignment of bond lengths d and change of bond angles θ, which directly affect the elastic properties of single crystals. The analytical expressions for determining the degree of ionicity on the Phillips, Born and Keating scales depending on the elastic anisotropy factor A were obtained.

M.P. Melnik, M.V. Uvarov, V.M. Uvarov

Electron Structure Research of Perovskite YMeО₃ ( Me = V, Ni) Oxides: X-ray Photoelectron Spectrum and Ab-Initio Calculation

G.V. Kurdyumov Institute for Metal Physics of the NASU, 36 Academician Vernadsky blvd., Kyiv, 03680, Ukraine

Using X-ray photoelectron spectroscopy as well as ab-initio band structure calculations by means of LAPW-method, complex research of electron structure and magnetic properties of YVO3 and YNiO3 oxides has been carried out. The distribution of total and partial electron densities in the valence and conductive bands as well as charge and spin states of constituent atoms were determined, and the mechanism of formation of the chemical bonds and band-gap in the energy spectra of the YMeO3 (Me =V, Ni) oxides was elucidated

D.М. Freik¹, S.І. Мudry², І.V. Gorichok¹, O.S. Krunutcky³, O.M. Matkivsky¹, T.S. Lyba¹, T.O. Semko¹

Phase Composition of Thermoelectric Materials Based on Solid Solutions PbTe-Sb₂Te3, PbTe-Bi2Te3

¹Vasyl Stefanyk Prekarpathian University, Shevchenko Str., 57, Ivano-Frankivsk, 76025, Ukraine, e-mail: fcss@pu.if.ua
²Ivan Franko National University of Lviv, Kyryla and Mefodiya Str., 8, Lviv, 79005 Ukraine 3Ivano-Frankivsk National Technical University of Oil and Gas, 15, Carpathian Str., Ivano-Frankivsk, 76001, Ukraine

X-ray investigation of thermoelectric materials based on solid solutions PbTe-Bi2Te3, PbTe-Sb2Te3 in the range of 0-5 ml. % Bi2Te3 (Sb2Te3) made it possible to establish dependences between the phase and structural state of the system on one side and the conditions of heat treatment and chemical composition of the samples on the other.

O.B. Tymoshuk, O.O. Kostyrko

Signs and Receipt of Multispin Metal- Radical Systems

Bogomolets National Medical University, Department of Medical and General Chemistry, Ukraine

The work is devoted to the synthesis of new polynuclear complexes of composition [Fe2 (III) M (II) O (p-NNPhCOO) 6 (MeCN) 3 ] • 2 MeCN ( M = Mn, Co, Ni). The results of mass spectrometry and infrared spectroscopy derived compounds that are allowed to establish their composition and structure. In the study of dependence of the magnetic susceptibility of complexes found between metal ions threenucleus skeleton [Fe2 (III) M (II) O] are antiferromagnetic interaction , and the presence nitronilnitroksil anions in the molecule complexes contribute to the magnetic exchange between two ions of iron ( III).
Keywords: synthesis, complexes, ligands d- metals, free radicals, magnetic properties, crystal structure, electronic structure.

V.М. Tomashyk¹, А.S. Stanetska¹, Z.F. Tomashyk¹, І.B. Stratiychuk¹, S.I. Budzuliak¹, S.M. Kalytchuk¹, S.М. Galkin²

Formation of Polished Surface of Undoped and Doped ZnSe crystals by H2O2–HBr– Ethylene Glycol Etchants

V. Lashkaryov Institute of Semiconductor Physics, National Academy of Sciences of Ukraine, 41 Nauki Ave., Kyiv, e-mail:tomashyk@isp.kiev.ru
²Institute for Scintillation Materials, National Academy of Sciences of Ukraine, 60 Lenin Ave, Kharkiv

The process of chemical polishing of the undoped and doped ZnSe crystals surface with H2O2 – HBr – ethylene glycol bromine emerging etchants has been studied. The dependence of the samples polishing rate on the concentration of H2O2 in basic solution, its stirring and temperature have been investigated. The phase diagrams of "etchants compositions – etching rate" have been constructed. The concentration regions of polishing solutions and the surface state after chemical etching have been established using atomic force, electron microscopy and low temperature photoluminescence. It was shown that the zinc selenide crystals surface state is improved after chemical etching. The concentration regions of polishing solutions for various types of ZnSe treatment have been found: to remove the damaged layer, to control the etching rate, to obtain samples of a given thickness.

J. Burunkova¹, I. Denisiuk¹ , C. Hegedus², L. Daroczi³, S. Charnovich³ , S. Kokenyesi³

Fabrication and Characterization of Gold/Acrylic Polymer Nanocomposites

¹ITMO, St.Petersburg, Russia, e-mail:burunj@list.ru, denisiuk@mail.ifmo.ru
²Faculty of Dentistry, University of Debrecen, Hungary, e-mail:chegedus@edu.unideb.hu
³Institute of Physics, University of Debrecen, Hungary, ldaroczi@tigris.klte.hu

We report the method of incorporation of preformed gold nanoparticles (AuNP) into the acrylic polymer (AP) matrices and optical, TEM characterization of AuNP/AP bulk and film composite. It was shown that incorporation of dodecanethiol-covered AuNP can be enhanced in the presence of SiO2 nanoparticles, enabling at the same time a wider range of tailoring of composite properties for optical processing or medical applications.
Keywords: Nanocomposite, acrylic polymer, gold nanoparticles, structure, optical recording.

А. Pidluzhna¹, I. Grygorchak¹, M. Nykypanchuk², S. Voitovych³

The Influence of Talc Intercalation Modification by Malladrite on Thermodynamic and Kinetic Parameters of Lithium-Intercalation Current Generation in Talc-Based Cathodes

¹Department of Applied Physics and Nanomaterial Science, Institute for Applied Mathematics and Fundamental Sciences, Lviv Polytechnic National University,
Kotlyarevsky str. 1, Lviv, 79013 Ukraine, e-mail:ussurian@yahoo.com
²Departmento of General Chemistry, Institute of Chemistry and Chemical Technologies, Lviv Polytechnic National University, Kotlyarevsky str. 1, Lviv, 79013 Ukraine 3Department for Biophysics, Informatics and Computers, Ivano-Frankivsk National Medical University, Galytska str 2, 76018 Ivano-Frankivsk, Ukraine

Natural talc was modified in two modes by annealing with malladrite at 400 0C and 800 0C for 2 h followed by washing with 0.1 M solution of nitric acid and distilled water. The effect of the modification on the parameters of lithium intercalation in talc based cathodes was investigated. As it was found the best mode of talc modification is the annealing with malladrite at 400 0C. It reduces the charge transfer resistance and leads to increase in specific capacity up to 650 mAh/g.
Keywords: talc, lithium electrochemical intercalation, impedance spectroscopy.

V.A. Mechnik

Evolution of Metal Bonding and Transition Zone Structure of Diamond(Fe-Cu-Ni-Sn and Diamond(Fe-Cu-Ni-Sn-CrB2

V.N. Bakul Institute for Superhard Materials. NAS of Ukraine, Kiev, 04074, Ukraine

Investigated evolution of metal bonding and transition zone structure of diamond ( Fe – Cu – Ni - Sn and diamond ( Fe – Cu – Ni – Sn - CrB2 sintered in molds in a muffle furnace with subsequent hot pressing. The mechanisms that contribute to the improvement of mechanical properties of such composites depending on their production technology have been elucidated.
Keywords: diamond, iron, copper, nickel, tin, interaction layer, transition zone, phase, composite, decarburization, pressure, temperature, structure, properties, wear resistance.

S.G. Orlovskaya

High Temperature Heat and Mass Transfer of Metal Particles with Account of Stefan Flow

Odessa National I.I. Mechnikov’s University, Odessa, Ukraine, Dvoryanskaya 2, 65082, (048) 723-62-27, svetor@rambler.ru

High temperature oxidation of metal particles is studied numerically: heat and mass transfer is modeled with account of metal oxide evaporation and Stefan flow at the particle surface. Analytical expressions for Stefan flow velocity, heat and mass flux at the surface are developed. Effect of Stefan flow on heat and mass transfer characteristics, including critical parameters of the particle extinction is analyzed numerically.
Keywords: heat and mass transfer, Stefan Flow, meal oxides, tungsten, molybdenum, ignition, extinction.

O.O.Sapyanenko¹, L.S.Dzubenko¹, P.P.Gorbyk¹, M.V.Tsebrenko², I.A.Mel’nyk², N.M.Rezanova²

The Influence of Nanodispersed Bactericidal Addition of Silver/Alumina on the Polypropylene Fibers’ Properties
¹O.O.Chuiko Institute of Surface Chemistry, NAS of Ukraine, 03164, Kyiv-164, 17, Generala Naumova Str., e-mail: ryash@i.ua
²Kyiv National University for Technologies and Design, 01011, Kyiv, Ukraine, 2, Nemyrovycha-Danchenko Str., e-mail: mfibers@ukr.net

There were polypropylene fibers containing addition combined of Ag/Al2O3 prepared. There was influence of addition on rheological behavior of polypropylene (PP) melt, crystalline structure forming and physico-mechanical properties of composite fibers. It is established, that fibers are containing particles of silver, and, at least, part of ones is nanodispersed. The presence of Ag/Al2O3 isn’t changing the PP flow mode, but leads to increase of melt viscosity and maximal possible spinneret drawing. It is established, that those fracture strength and elasticity modulus of composite fibers are increased. The influence of Ag/Al2O3 on structure consists in temperature range expansion of PP melting and increase of main peak temperature (Тпл or Tm). This shows on, that the most part of PP crystallites were formed at increased temperatures, i.e., at conditions, mostly approximated to equilibrium ones, assisting formation of larger and perfect crystallites.

M.M. Martyniuk, N.I. Domantsevych, B.P. Yatsyshyn

Structural and Defect Formation of Polymer, Modified by Secondary Raw Materials

Structural investigations and mechanical tests of polymer materials, modified by dye and secondary raw supplies, were carried out. Peculiarity of the structure formation, depending on amount and types adding, also as defect engender, were determined by electronic microscopic explorations.

A.B. Lysenko, I.V. Zagorulko, Т.V. Kalinina, A.A. Kazantseva

Conditions of Crystal Nucleation Processes Suppression at the Quenching from a Liquid State

Dnieprodzerzhinsk State Technical University, 51918, Dnieprodzerzhinsk, Dnieprostroevska str., 2, e-mail:ablysenko@ukr.net

The estimation method of the melt critical cooling rate at which the nucleation processes are completely suppressed and fixed truly amorphous structure that does not contain "quenched nuclei" crystalline phase, is suggested. The calculations of values were performed for materials with significantly different glass forming ability: pure metals (Al, Ni), alloy Fe80B20 and the bulk amorphized alloys (Mg65Cu25Y10 and Zr41.2Ti13.8Cu12.5Ni10Be22.5). It is shown that to prevent the crystallization in the pure metals melts are necessary cooling rates ~ 1013 - 1014 K•s-1. Applied to the bulk amorphized alloys values are decreased up to ~ 104 K•s-1 that indicates the principal possibility of truly amorphous states obtaining in the products of rapid quenching with the cross sections to about ~ 130 μm.
Keywords: quenching from a liquid state, melt cooling rate, truly amorphous state, nucleation frequency.

B.K. Ostafiychuk¹, I.М. Budzulyak¹, N.Y. Ivanichok¹, R.P. Lisovski², B.I. Rachiy¹

The Effect of Thermal Modification on Development of Carbon Materials Microporous Structure

1Vasyl Stefanyk Precarpathian National University, 57 Shevchenko Str., Ivano-Frankivsk, 76018, Ukraine 2G.V. Kurdyumov Institute for Metal Physics of the NASU, 36 Academician Vernadsky blvd., Kyiv, 03680, Ukraine

A comparison of the characteristics of microporous structure of both initial and thermally modified (673 K, 180 min) carbon material from raw material of plant origin is realized. These characteristics of the porous system are calculated by different methods based on low-temperature isotherms (77 K) of nitrogen adsorption-desorption. It is found out that thermal modification promotes the development of surface (from 361 m2/g to 673 m2/g), increasing the total pore volume (from 0,166 cm3/g to 0,477 cm3/g) and micropore volume (from 0,127 cm3/g to 0,173 cm3/g). The most effective thermal modification promotes the formation of nanopores with diameter of 0,75 nm, 1,25 nm, and 4 nm. Keywords: porous carbon material, thermal modification, low-temperature porometry, structural and adsorption characteristics.

A.S. Zavojco, S.N. Novicov

Mechanization Processes Electric Sparking-Over Ligature in Connection Reaction of Gas

¹Chernivtsi department of NTU "KPI", Chernivtsi, 58000, Ukraine
²Yuriy Fedkovych National University, Chernivtsi, 58012, Ukraine

This article considered the new basic physical-technical obtained and strengthening with help double processes electric lightning ligature and gas connection condensation on steel in the new picture. This two process penetration the theory binding material, electrodynamics frictional induction electrode material on steel basic and developed practical making gas solution dipping with the obtained new composite types will continue of protective coatings based on metals with new mechanical and physics-chemical processes process of need . Special priority rating in future research will be given to working out theoretical bases and production processes of obtaining height-strength materials reinforced with metal and ways of predetermining lasting stress-strain characteristics with a view to establishing principles of designing composite materials with clear-cut anisotropic characteristics, outlining new spheres of national economy which could use composite materials; theoretical and experimental research in materials for outer space; studying process which take place in materials under the effect of vacuum, low temperatures, various types of radiation and meteoritic particles; developing materials for space engineering, machine interpolice contact ligature in steel. In this article considered categories of materials differ from each other by their microstructure, precipitation-strength honed composition have a microstructure whitch constitutes a matrics of a basic electric ligature substance or alloy with uniformly dispersed particles 0,01 to 0,1 μm in size in the amount of 1 to 15 % of a volume part. The chapter of the article will inform the reader of how new protective ligature coatings prolong service life of machines, mechanisms, instruments and other equipment, and will tell you about the main task materials and their use in systems and structures that determine the level of the modern scientific and technical progress of the obtained in new equipment, power-plant.
Keywords: process electric lightning ligature, gas condensation, binding material, electrodynamics frictional induction, protective coating, height-strength materials.

R.I. Nykyruy

Technology of ZnS Nanostructures: Deposition from Gas-Dynamic Stream of Steam

Vasyl Stefanyk Precarpathian national University, 57, Shechenko Str., Ivano-Frankivsk, Ukraine e-mail:freik@pu.if.ua

There are the analytical expressions for the basic parameters of gas-dynamic stream of steam into the cylindrical chamber and calculated their profiles for zinc sulfide, depending on the geometrical dimensions of the camera temperature gradient along its walls, the nature of the material and its temperature evaporation.

I.V. Gorichok¹, A.I. Tkachuk^1,2, O.S. Krunutcky², O.M. Matkivsky¹

Determination of Semiconductors Thermal Conductivity by Radial Heat Flow

¹Vasyl Stefanyk PreCarpathian National University 57, Shevchenko Str., Ivano-Frankivsk, 76018, Ukraine, E-mail:fcss@pu.if.ua
²Ivano-Frankivsk National Technical University of Oil and Gas, 15, Karpatska Str., Ivano-Frankivsk, 76019, Ukraine

Depicting setting for measuring the thermal conductivity of semiconductor materials by radial heat flow. The technique has been tested on samples of thermoelectric lead telluride. Keywords: thermal conductivity, heat flow, research methods.

L.A. Frolov, О.A. Pivovarov, E.G. Tsopych

Preparation of Nickel Ferrite Concentrated Wastewater

Ukrainian State University of Chemical Technology", Dnipropetrovsk,Ukraine, e-mail:ugxtu@dicht.dnepropetrovsk.ua

Possibility of receipt of ferrit of nickel from the concentrated sewages by a hydrothermal method is investigated. Kinetics of process is studied. Influence of basic parameters of процеса is considered on phase composition of the got powders
Keywords: sewages, cleaning chart, ferrit of nickel

T.B. Gheplynskiy, О.К. Serkiz

The Dependence of Microhardness 6 mm Float Glass Sheet on the Conditions of its Determination

Lviv Polytechnic National University Lviv, 79013, Ukraine

It was investigated the change of microhardness values of 6 mm float glass, depending on the measurement conditions. It was established that the value of microhardness depends on surface moisture, the load on indentor and duration time. It were chosen the optimal parameters of microhardness measurement of 6 mm float glass.
Keywords: microhardness, conditions of measurement, surface humidity, load on indentor, float glass.

V.О. Kotsyubynsky¹, V.V. Moklyak², A.B. Hrubiak¹

Sol-Gel Citrate Synthesis of Mesoporous Iron Oxides. I. Hydrolysis and Polycondensation

¹Vasyl Stefanyk Precarpathian National University, 57 Shevchenko Str., Ivano-Frankivsk, 76025, Ukraine, v_kotsuybynsky@mail.ru
²Institute of Metal Physics, National Academy of Science, 36 Aс. Vernadsky Boulevard., Kyiv, 03680, Ukraine, mvvmcv@mail.ru

The detailed analysis of the citrate sol-gel synthesis progress of iron oxides was made. The stages of Fe (III) hydrocomplexes formation and polycondensation was studied and citrate anions influence on these processes was discussed. It was found that at pH = 2-3 unstable mononuclear bidentate iron citrate complexes are formed, whereas at pH> 7-8 the tridentate mononuclear complex ions are dominated. The improving of Ostromyslenskoho-Zhoba method are presented and a equilibrium constant of bidentate iron citrate complexes formation reaction was obtained.
Keywords: iron oxide, iron citrate, hydrolysis, the hydrocomplexes, polycondensation, the sol-gel method.

R.A. Pelensky

Prospects for Solar Energy

Lviv Polytechnic National University

The article analyses solar energy engineering growth opportunities based on carbon nanostructures {growth opportunities for solar energy engineering}.Ukraines energy supply through the development of the solar power plants becomes a reality.