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(17/04) Курс “Анализ геномных данных”, Москва, 2 – 11 июля 2012
Уважаемые коллеги, Со 2 по 11 июля 2012 года Учебный центр Института биологии гена РАН организует практический десятидневный курс по статистическому анализу геномных дан...
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(12/03) Впервые получено изображение атомов, движущихся в молекуле
Исследователи из Университетов Огайо и Канзаса впервые смогли получить изображения атомов, движущихся в молекуле. С помощью ультрабыстрого лазера исследователи выбивали элек...
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(12/03) Наблюдение за распределением зарядов в молекуле
Исследователи из Швейцарии впервые с помощью экспериментов смогли визуализировать распределение зарядов отдельной молекуле. Предполагается, что результаты работы могут при...
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(22/01) Простой способ разделения углеродных нанотрубок
Существуют одностенные углеродные нанотрубки [single-walled carbon nanotubes (SWCNT)] с металлическим и полупроводниковым типом проводимости, однако для использования этих...
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Результаты 1 - 10 из 15

Recent Trends in Experimental and Theoretical Investigations of Chemisorption on Metal-Electrolyte Interface. II. Contact Electric Resistance Method1,2

V. A. Marichev


Department of Chemistry, University of Western Ontario, London, Ontario, Canada

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Abstract — New trends in experimental and theoretical investigations of chemisorption on electrodes are considered on examples of in situ spectroscopic studies and the density functional theory calculations. The partial charge transfer during ionic and molecular adsorption from aqueous solutions on coinage and platinum metals and the thermodynamic uncertainty regarding the direction of the charge transfer are discussed. The contact electric resistance technique (CER) was shown to offer a new approach to considering these problems. This technique provides information on the coefficient and direction of the charge transfer, the kinetics of the transformation of the electrode surface during the conversion of adsorbed ions to adatoms, and the role of competitive adsorption of water. It was examined how the charge transfer is related to the electrosorption valence of anions and what the role plays the tunneling of electrons in the generation of the CER signal. The CER was demonstrated to be dependent on the potential E, the coverage, and the residence charge of the adsorbate. For the adsorption of halide ions from aqueous solutions on 1B metals, the bell shaped CER vs. E dependences were obtained. The maxima in these dependences correspond to the onset of substantial charge transfer, their position and amplitudes being determined by the nature of the metal and anion and the concentration of the latter. At E< Emax, halide ions are adsorbed without appreciable charge transfer; within the range Emax (Emax 0.1 V), the charge transfer for silver and gold approaches 1, being far less for copper. For a given metal, Emax increases in the series frame0 < frame1 frame2 frame3 while for a given anion, Emax increases in the series Au < Ag frame4 Cu. Based on the measured CER-E dependences, a quantitative criterion of the substantial charge transfer during ionic and molecular adsorption was proposed. This criterion was demonstrated to be consistent with the published data on charge transfer in various adsorbate-adsorbent systems. In particular, it shows that the hydrophilicity and electronic properties of 1B metals differently influence charge transfer during ionic and molecular adsorption. New electrosorption equations have been proposed describing the partial charge transfer and screening of the adsorbate charge due to partial ionization of the surface atoms. An experimental approach to solve the “anion problem” in the density functional theory has been developed basing on the CER-measured values of Emax in corresponding electrochemical systems.

PACS numbers: 68.43.–h, 78.30.–j


DOI: 10.1134/S2070205109030010
22/06/2009 | 750 Посещения | Печать


Kinetics of Phase Transformations in a Binary Alloy Surface Layer at the Selective Dissolution. II. Agframe0Au|Ag+* System

O. A. Kozaderov, A. V. Vvedenskii, and O. V. Koroleva


Voronezh State University, Universitetskaya pl. 1, Voronezh, 394006 Russia

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Received April 12, 2008


Abstract — Based on the theoretical investigation [1], the conditions of phase transformation of gold on Ag–Au alloy surfaces, which are selectively dissolved in a nitrate environment at the overcritical anodic polarization, are experimentally found. Kinetic regularities of the formation of Au° individual gold phase on the alloy surface depending on the alloy composition and overpotential, as well as on the presence of surface active organic substances in the solutions and the passivating alloying additives in the alloy are determined.

PACS numbers: 82.45.Qr


DOI: 10.1134/S2070205109030022
22/06/2009 | 768 Посещения | Печать


Influence of the Composition of the Liquid Phase and the Concentration of Benzohydrazide on Its Effectiveness during Cadmium Electrodeposition from Waterframe0Acetone Perchlorate Electrolytes

V. V. Kuznetsov, L. M. Skibina, and R. R. Khalikov 


Department of Chemistry, Southern Federal University, ul. Zorge 7, Rostov-on-Don, 344090 Russia

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Received May 3, 2007


Abstract — Cadmium–benzohydrazide complexes (2 : 1) were found to be the main electroactive species in cadmium electrodeposition from water–acetone perchlorate baths. The discharge of these complexes is preceded by their dissociation at the cathode (zone of water structure stabilization) or in the bulk of the solution (zone of acetone structure stabilization). In the microheterogeneity zone of the mixed solvent, the complexes can be reduced from the adsorbed state. The process is best inhibited at low concentrations of benzohydrazide (frame1 = 10frame24 mol/l), when the electrode is covered with a very dense layer of adsorbed benzohydrazide and acetone molecules. With an increase in frame3, perchlorate anions become more adsorbable, which is accompanied by increasing facilitation of the discharge reaction ('-effect). The strongest depolarizing effect of Clframe4 anions is observed in the zone of acetone structure stabilization, which is due to selective solvation of the anion and the desalting effect of the mixed solvent.


PACS numbers: 82.45.-Qr

DOI: 10.1134/S2070205109030034
22/06/2009 | 833 Посещения | Печать


Comparative Analysis of the Adsorption of the Stereoisomers of Hydroxy- and Dihydroxyproline at Graphitized Thermal Soot

E. S. Kuznetsova, A. V. Ul’yanov, and A. K. Buryak


Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences,
Leninskii pr. 31, Moscow, 119991 Russia

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Received June 5, 2008


Abstract — The thermodynamic characteristics of the adsorption of proline and its derivatives at graphitized thermal soot (GTS) were determined. It was found that the arrangement of the hydroxy groups in the amino acid molecule influences its adsorption at GTS. The thermodynamic characteristics of the adsorption of the stereoisomers of hydroxy- and dihydroxyproline at GTS were calculated. The influence of the internal rotation angles in the molecules of proline and its derivatives on their adsorption at GTS was studied.


PACS number: 68.43.De

DOI: 10.1134/S2070205109030046
22/06/2009 | 788 Посещения | Печать


Determination of the Flory - Huggins Parameter for a Pair of Polymer Units from AFM Data for Thin Filmsof Block Copolymers

E. A. Men’shikov1,2, A. V. Bol’shakova2, and I. V. Yaminskii2


1 Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, Leninskii pr. 31, Moscow,
119991 Russia

2 Faculty of Physics, Moscow State University, Moscow, 119992 Russia

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Received March 6, 2008


Abstract — The structures of thin films of the polystyrene–polybutadiene–polystyrene (SBS) and polystyrene–poly(methyl acrylate)–polystyrene (SMAS) triblock copolymers were studied. The film morphology was found to depend on the conditions of film formation. The average domain sizes of these films and the period of the lamellar structure of SMAS films were determined. The Flory–Huggins parameter was estimated for a pair of styrene and methyl acrylate units.

PACS numbers: 87.64.Dz

DOI: 10.1134/S2070205109030058
22/06/2009 | 810 Посещения | Печать


Electrocrystallization and Physicochemical Properties of Nanosized Copper-Containing Powders

S. A. Chulovskaya1 and V. I. Parfenyuk2


1Institute of Chemistry of Solutions, Russian Academy of Sciences, Akademicheskaya 1, Ivanovo, 153045 Russia

2Ivanovo State University of Chemistry and Technology, pr. F. Engel’s 7, Ivanovo, 153000 Russia

Received November 16, 2007


Abstract — The electroctystallization mechanism of copper-containing powders from water–isopropanol solutions of copper dichloride is studied. The effect of the nature and concentration of solution components on the electroplating of cathodic deposits is considered. Morphological characteristics of particles of the synthesized powder are determined on a transmission electron microscope. The qualitative composition of synthesized powders is determined.


PACS number: 81.07.Wz, 81.07.-b

DOI: 10.1134/S207020510903006X
22/06/2009 | 772 Посещения | Печать


Corrosion Protection of Mild Steel by Applying TiO2 Nanoparticle Coating via Sol-Gel Method1

A. Shanaghi, A. R. Sabour, T. Shahrabi, and M. Aliofkhazraee


Surface Engineering Laboratory, Materials Engineering Department, Faculty of Engineering, Iran, Tehran, Tarbiat Modares
Unversity, P.O. Box: 14115–143

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Received November 2, 2007


Abstract — TiO2 nanoparticle coatings possess good thermal and electrical properties and they are resistant to oxidation, corrosion, erosion and wear in high temperature environments. This property is very important factor in the applications such as pipelines, castings and automotive industry. In this investigation a uniform TiO2 nanoparticle coating has been applied on mild steel, using sol-gel method. The coating was deposited on mild steel substrate by dip coating technique. The morphology and structure of the coating were analyzed using SEM, AFM and X-ray diffraction. The anticorrosion performances of the coating have been evaluated by using electrochemical techniques. It is worthy to note that the film uniformity was retained in high temperatures and no crack and flaking off from the substrate was observed. The Tafel polarization measurements provide an explanation to the increased resistance of TiO2 nanoparticle coated mild steel against corrosion and icorr was decreased from 18.621 to 0.174 A/cm2.


PACS numbers:

DOI: 10.1134/S2070205109030071
22/06/2009 | 786 Посещения | Печать


Composite Electrochemical Coatings: Preparation, Structure, Properties

V. N. Tseluikin


Engels Technological Institute (Affiliated Branch) of Saratov State Technical University,
pl. Svobody 17, Engels, Saratov Oblast’, 413100 Russia

Received May 19, 2008


Abstract — Results of studies in the field of electrochemical composition coatings (ECC) are presented. Methods of synthesis, functional properties, and structural peculiarities of the main types of ECC are considered.

PACS numbers: 81.05.Ni, 82.45.Qr

DOI: 10.1134/S2070205109030083
22/06/2009 | 879 Посещения | Печать


PbO2frame0TiO2 Composite Electrodes

A. B. Velichenko1, V. A. Knysh1, T. V. Luk’yanenko1, F. I. Danilov1, and D. Devilliers2


1 Ukrainian State University of Chemical Technology, pr. Gagarina 8, Dnepropetrovsk, 49005 Ukraine

2 Pierre and Marie Curie University (Paris 6), pl. Jussieu 4, Paris, 75252 France

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Received May 20, 2008


Abstract — Electrodeposition of composite PbO2-based materials containing titanium dioxide particles was studied. The TiO2 content of the composite depends on the bath composition and the deposition conditions. Inclusion of TiO2 particles in PbO2 substantially changes the morphology and structure of the deposit. The oxygen overpotential at composite materials increased but the rate of the conversion of 4-chlorophenol into nontoxic compounds remained virtually unchanged. The lifetime of the electrodes containing the inert TiO2 phase was found to be twice as long as that of traditional PbO2 anodes.

PACS numbers: 81.05.Ni, 82.45.Qr


DOI: 10.1134/S2070205109030095
22/06/2009 | 922 Посещения | Печать


Solving Modern Problems of a Coatingframe0Substrate System in a Viscoelastic Approximation

N. O. Gonchukova


Institute of Silicate Chemistry, Russian Academy of Sciences, nab. Adm. Makarova 2, St.-Petersburg, 199034 Russia

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Received November 19, 2007


Abstract — Calculated stresses in amorphous metallic coatings, which were produced by plasma spray method and chemical deposition, are discussed. These coatings may serve as wear- and corrosionresistant coatings and magnetic shields. The calculations of stresses are carried out for composites containing chalcogenide glasses, which are used in electronics and optics.

PACS numbers: 68.60.Bs


DOI: 10.1134/S2070205109030101
22/06/2009 | 885 Посещения | Печать

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