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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 134
1.

Recent Trends in Experimental and Theoretical Investigations of Chemisorptions on Metal-Electrolyte Interface.  In Situ Spectroscopic Studies and the Density Functional Theory Calculations

V. A. Marichev*

 

Department of Chemistry, University of Western Ontario, London, N6A 5B7, Ontario, Canada

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Received May 14, 2007

 
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.

 

PACS numbers: 68.43.-h, 78.30.-j

DOI: 10.1134/S2070205109010018
11/02/2009 | 954 Посещения | Печать

2.

Equilibrium Adsorption of Stilbenoids at Metal Oxides

P. N. Kolotilov, K. E. Polunin, I. A. Polunina, and A. V. Larin

 

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

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Received February 02, 2008

 

Abstract — The isotherms of adsorption of trans-hydroxystilbenes (stilbenoids) and hydroxybenzenes (phenols) from n-hexane–ethyl acetate (1 : 1) at nanodispersed aerogels of aluminum and titanium oxides were measured under static conditions. The adsorption isotherms can be approximated well by the Freundlich equation for the model of localized adsorption at energetically heterogeneous solids. It was found that the adsorption value of both stilbenoids and phenols is improved with an increase in the number of OH groups in their molecules, being sensitive to the chemistry of the adsorbent surface. trans-Hydroxystilbenes adsorb at TiO2 better than do the corresponding phenols. The opposite pattern was observed for Al2O3. The adsorption of transhydroxystilbenes at TiO2 is irreversible and accompanied by the formation of colored surface compounds.

 

PACS numbers: 68.43.-h

DOI: 10.1134/S207020510901002X
11/02/2009 | 901 Посещения | Печать

3.

Hydrogen Overvoltage at Manganese in Ammonium-Bromide-Perchloric Solution

L. F. Kozin, N. V. Mashkova, and F. D. Manilevich

 

Institute of General and Inorganic Chemistry, National Academy of Sciences of Ukraine,
pr. Palladina 32–34, Kiev, 252142 Ukraine

Received July 3, 2007

 

Abstract — Kinetic characteristics of electrochemical hydrogen evolution at manganese rotating disc electrode in ammonium-bromide-perchloric solution at 18, 40, and 60°C are determined (the overvoltage, Tafel slopes, exchange currents, and activation energy). The zero-charge potential is found. Mechanism of the electrode process is suggested. It is shown that S-shaped bends in the polarization curves of hydrogen evolution can be entailed with changes in the electrode surface charge. The overvoltage and current density corresponding to beginning of the activationless range of electrochemical hydrogen evolution are determined.

 

PACS numbers: 82.45.Hk, 82.45.Qr

DOI: 10.1134/S2070205109010031
11/02/2009 | 908 Посещения | Печать

4.

Kinetics of Phase Transformations in a Binary Alloy Surface Layer at the Selective Dissolution. I. Theoretical Analysis

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

 

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

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Received April 10, 2008

 

Abstract — A procedure of estimating the formation rate of the individual phase of an electrochemically positive component B0 at the anodic selective dissolution or corrosion of an A–B alloy in a potential range above the critical potential of the development of a morphologically unstable surface is proposed and theoretically founded.

PACS numbers: 82.45.Qr

DOI: 10.1134/S2070205109010043
11/02/2009 | 1019 Посещения | Печать

5.

Adsorption of Copper Cations at Chitosan Samples Prepared by Lyophilic Drying

O. V. Solovtsova, T. Yu. Grankina, O. K. Krasil’nikova, N. V. Serebryakova, and S. M. Shinkarev*

 

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

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* All-Russia Research and Technological Institute for Biological Industry, B.O. Kashintsevo, Moscow oblast, 141142 Russia

Received September 15, 2007

 

Abstract—Supramolecular structures of copper complexes with chitosan were studied by spectroscopic methods to understand better the adsorption of metal cations by polysaccharides. Sublimation drying of chitosan was found to influence the adsorption of copper cations by the resulting polymer adsorbents with supramolecular structures. The conditions for preliminary drying of the water-swollen adsorbents (in particular, chitosan) are decisive for the relative positions of chains and the arrangement of adsorption amino sites. According to spectroscopic data, copper cations form various complexes with amino groups, depending on the supramolecular structure of chitosan. Sublimation drying of chitosan substantially enhances the adsorption of metal cations. The sorption capacities of chitosan samples prepared by sublimation drying, reprecipitation with soda and sublimation drying, and air drying were 5.1, 4.0, and 1.8 mmol/g, respectively. The resulting adsorption isotherms were described by the Dubinin–Radushkevich equation for a wide range of surface coverages. This made it possible to calculate the effective adsorption energies of the systems studied.

 

PACS numbers: 68.43.-h, 81.16.Fq

DOI: 10.1134/S2070205109010055
11/02/2009 | 984 Посещения | Печать

6.

The Effect of Transform PVC Surface Layers into Ethanol Cyclam Nanofilms on the Thermodynamic and Thermomechanical Properties of the Material

A. Ya. Fridman, A. Yu. Tsivadze, E. M. Morozova, N. P. Sokolova, M. R. Kiselev, I. I. Bardyshev,
A. M. Gorbunov, and O. P. Shapokhina

 

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

Received July 23, 2007

 

Abstract — The effect of forming a polymer–polymer “continuous rigid ethanol cyclam coating–ductile PVC support” system on the thermodynamic and thermomechanical characteristics is studied from the standpoint of variations in the surface layer structure and the ratio of ordered to disordered PVC forms. It is shown that the transforming surface layers of PVC materials in to rigid films provides possibilities for targeted modification of the materials properties by using the methods of nanotechnology.

 

PACS numbers: 68.47.Pe, 82.35.Gh

DOI: 10.1134/S2070205109010067
11/02/2009 | 1059 Посещения | Печать

7.

Inhibition Effects of Methionine and Tyrosine on Corrosion of Iron in HCl Solution: Electrochemical, FTIR, and Quantum-Chemical Study

S. Zor, F. Kandemirli, and M. Bingul

 

Department of Chemistry, Kocaeli University, Kocaeli, 41380, Turkey

Received October 26, 2007

 

Abstract — The inhibiting effect of methionine and tyrosine on the corrosion of iron is researched electrochemically in 0.1M HCl, Quantum chemical calculations were performed. The level of HF with the 6–311G(d,p)basis set for methionine and tyrosine. Corrosion current density has been determined by polarization measures and the inhibition effect was calculated. With an increase in the concentration of inhibitor, the effectiveness of inhibition increases. The highest inhibition is determined as 97.8% at 100 ppm methionine. The effect of temperature is determined by chronoammetric measures. Surface analysis is performed with FTIR spectroscopy. Methionine and tyrosine adsorb on the iron surface according to Langmiur isotherm. The highest occupied and the lowest unoccupied molecular orbital energy, as well as Mulliken and atomic charges with hydrogens summed into heavy atoms of C, N, O, S atoms and of methionine, tyrosine, and protonated forms have been examined.

 

PACS numbers: 81.65.Kn, 68.43.-h

DOI: 10.1134/S2070205109010079
11/02/2009 | 1050 Посещения | Печать

8.

Adsorption and Oxidation Processes in Modern Nanotechnologies

A. A. Revina

 

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

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Received July 10, 2007

 

Abstract — Among the fields in which Russian science can chalk up, of primary importance are nanotechnologies involving nanosized-particles-based modern materials with preset properties. The specific properties of metallic nanoparticles open up wide possibilities of preparing novel materials in electronics, effective catalysts, filtering elements, biosensors, medications with high biological activity for medical, biotechnological, and agricultural applications. Physical chemistry is extremely important in the creation of interdisciplinary basic foundation of nanochemistry and applied nanotechnology of XXI century [1–4]. The methods of synthesis, in inversed micelles, of metallic nanoparticles, stable in liquid phase and in nanocomposites and showing charac-teristic bands of optical UV–vis absorption, allow using modern physicochemical methods of studying the nanostructure formation, properties, and polyfunctional activity [5–10]. The results of the studies of adsorption processes of the metal nanosized aggregates in solutions, obtained by using chromatography (high-performance liquid chromatography, thin-layer chromatography, gas chromatography) and demonstrating the important role of active surface centers and molecular interactions, may serve as a theoretical basis in producing new nanocomposite materials with unique properties [10–12].

 

PACS numbers: 68.43.-h, 81.16.-c

DOI: 10.1134/S2070205109010080
11/02/2009 | 977 Посещения | Печать

9.

Chemical and Phase Composition of Nanosize Oxide and Passive Films on Niframe0Cr Alloys. I. XPS Studies of Films Obtained by Alloy Oxidation In Air

Yu. Ya. Andreev,* E. A. Skryleva, I. A. Safonov, and V. V. Dushik

 

Moscow State Institute of Steel and Alloys, Leninskii pr. 4, Moscow, 119991 Russia

* E-mail: Этот e-mail защищен от спам-ботов. Для его просмотра в вашем браузере должна быть включена поддержка Java-script

Received April 9, 2008

 

Abstract — XPS data for thin (less than 100 nm) oxide films obtained by oxidation of Ni–4 Cr and Ni–12.5 Cr alloys at 500°C (0.5 h) are discussed. Thermodynamic analysis of 3 NiO + 2 Cr = Cr2O3 + 3 Ni solid-phase reaction is given, in which both the Gibbs energy change in the thermochemical process and the change in the interface energy at the alloy–oxide film boundary are taken into account.

 

PACS numbers: 81.65.Mq, 81.07.-b

DOI: 10.1134/S2070205109010092
11/02/2009 | 932 Посещения | Печать

10.

Formation of Nanoporous Oxide at Aluminum Anodizing

A. I. Shcherbakov, I. B. Skvortsova, V. I. Zolotarevskii, G. P. Chernova, and V. E. Mashchenko

 

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

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Received May 26, 2008

 

Abstract — The effect of electrochemical anodic oxidation on the formation of porous anodic oxide films (PAOF) on a high-grade aluminum (99.99%) in a sulfuric acid solution is studied. Anodizing modes are chosen such as to obtain PAOF with ordered nanostructure. It is shown that under an atomic force microscope, the anodic film reveals a cellular structure. The parameters of the latter are as follows: diameters of a pore (30–35 nm) and a circle circumscribed around a hexahedral cell (90 nm). A possible mechanism of the formation of regular nanoporous structures of anodic aluminum oxide is proposed.

 

PACS numbers: 82.45.Cc, 81.71.-b

DOI: 10.1134/S2070205109010109
11/02/2009 | 949 Посещения | Печать

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