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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 14
1.

Corrosion of Uranium and Its Low Content Zr, Nb, and Ru Alloys in Aqueous Solutions

V. F. Peretrukhin, A. G. Maslennikov, A. Yu. Tsivadze, C. H. Delegard*, A. B. Yusov, V. P. Shilov,  A. A. Bessonov, K. E. German, A. M. Fedoseev, L. P. Kazanskii, N. Yu. Budanova, A. V. Kareta, A. V. Gogolev, K. N. Gedgovd, and G. S. Bulato

 

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

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*Pacific Northwest National Laboratory, P. O. Box 999, Richland, WA, USA

Received August 14, 200

 

Abstract — Corrosion of uranium and its alloys with low content (0.5–5.0 at %) of Zr, Nb, and Ru in water and bicarbonate aqueous solutions is studied; the effect of hydrogen peroxide, the main product of radiation pro-cesses, on the corrosion rate is elucidated. The rate of the primary corrosion process U + (2 + n)H2O = UO2 · nH2O + 2H2 is measured by electrochemical methods in anaerobic and aerobic conditions for uranium metal and its alloys containing 0.5 to 5.0 at % of Zr, Nb, and Ru. It is shown that the corrosion rates for the alloys are lower than that of reactor-grade uranium; however, the difference is rather close to the measurement error. The corrosion mechanism is studied; U(III) is shown to be rather unstable in neutral solutions when uranium(III) hydroxide is precipitated and no significant amount of U(III) and UH3 is present among the products of the metallic uranium corrosion in water. The kinetics of the second corrosion stage U(IV) + O2 frame0 U(VI) is studied by spectrophotometric method. It is shown that the reaction of U(IV) oxidation by atmospheric oxygen is similar in weakly acid solutions (pH 1.5–4.0) and in bicarbonate media: in particular, it has an induction period for uranium (IV) accumulation, after which the reaction accelerates; it is formally a first-order reaction with respect to uranium. The reaction mechanisms differ in the two media: in weakly acid solutions, after the appearance of U(VI), the reproportionation reaction proceeds; thus formed U(V) interacts with O2 faster than U(IV). In the bicarbonate medium, the acceleration of the reaction is due to the formation of a [U(IV)sumU(VI)] complex whose reactivity is higher than that of uranium (IV). In the absence of bicarbonate, of great importance is the formation of a copolymer of U(IV) and U(VI), which at pH 4 prevents formation of U(V). It is shown that on the introduction of hydrogen peroxide to aqueous solutions, the metallic uranium surface becomes transpassive, which increases the rate of corrosion process by at least an order of magnitude,. The introducing of oxidants and platinum mesh lowers the hydrogen accumulation at 120frame1150frame2C and, hence, the hydrogen-explosion danger of the uranium–water–corrosion-products system. Methods of deposition of metal oxide (Tc, Ru, Mo, W)  films onto uranium surfaces by immersing uranium metal into Tc(VII), Ru(VI), or Mo and W heteropoly compound solutions are studied.

PACS numbers: 82.45.Bb, 81.65.Kh

DOI: 10.1134/S0033173208030016
03/09/2008 | 920 Посещения | Печать

2.

Estimating the Minimum Pore Size in Globular Systems with Capillary Hysteresis

Yu. K. Tovbin and A. G. Petukhov

 

Karpov Institute of Physical Chemistry, ul Vorontsovo Pole 10, Moscow, 105064 Russia

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Received June 15, 2007

 

Abstract — A technique of estimating the minimum size of pores in regular globular structures, the isotherms of which may have a hysteresis loop that indicates the capillary condensation, is proposed. As a criterion of the minimum pore size, the contribution from the middle pore volume unaffected by the wall potential, which was found from the experimental data for infinitely long cylindrical channels, is used. The estimates for regular globular structures are compared to the similar estimates for spherical and cubic pores. The ways of taking into account the restricted size of pores in the case of irregular globular packing are discussed.

PACS numbers: 47.55.nb

DOI: 10.1134/S003317320803003X
03/09/2008 | 859 Посещения | Печать

3.

Molecular Statistics Calculations of Thermodynamic Characteristics of the Adsorption of Isomeric Amino Acids on Graphitized Thermal Black

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

Received June 26, 2007

 

Abstract — Thermodynamic characteristics of the adsorption of several isomeric amino acids on graphitized thermal black (GTB) are calculated by a molecular statistics method. Parameters of the potential function of the intermolecular pair interaction between an O atom of amino acid and a C atom of graphite are calculated.

PACS numbers: 68.43.De

DOI: 10.1134/S0033173208030041
03/09/2008 | 905 Посещения | Печать

4.

Adsorption of Inhibitors Based on Vegetable Raw Materials at Steel

O. I. Sizaya, O. N. Savchenko, A. A. Korolev, and V. G. Ushakov

 

Chernigov State Technological University, ul. Shevchenko 95, Chernigov, 14027 Ukraine

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Received April 3, 2007

 

Abstract — The adsorption mechanism of corrosion inhibitors prepared from the modified vegetable oil (MGframe0ChDTU and MGS) and the water-soluble fraction of vegetable product wastes (FES) was studied. It was found that the inhibitors both chemisorb and physically adsorb at steel to form polymolecular protective layers.

PACS numbers: 82.45.B

DOI: 10.1134/S0033173208030053
03/09/2008 | 936 Посещения | Печать

5.

Electrochemical Synthesis of Ultradispersed Copper-Containing Powders Obtained from Solutions of Copper Nitrates in Aqueous Propan-2-ol

V. I. Parfenyuk*,** and M. V. Tesakova*

 

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

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** Ivanovo State University of Chemical Technology, pr. F. Engel’sa 7, Ivanovo, 153000 Russia

Received October 25, 2006

 

Abstract — Nanosized copper-containing powders were obtained by electrochemical synthesis in aqueous organic solutions of electrolytes. The size and shape of the resulting particles were determined by TEM. It was found that the electrochemical crystallization of copper-containing deposits is substantially influenced by the solvent nature. Adding an organic solvent to the electrolyte increased the dispersivity of the powders. A quali-tative analysis of the compounds obtained was carried out by electron diffraction analysis.

PACS numbers: 81.07.Wx, 82.45.Qr

DOI: 10.1134/S0033173208030065
03/09/2008 | 850 Посещения | Печать

6.

The Mechanism of Formation of Thin Oxide Coatings and Nanopowders at the Anodic Oxidation of Zirconium in Molten Salts

L. A. Elshina, V. Ya. Kudyakov, V. B. Malkov, N. G. Molchanov, and B. D. Antonov

 

Institute of High-Temperature Electrochemistry, Ural Division, Russian Academy of Science, Ekaterinburg, Russia

Received February 16, 2007

 

Abstract — At the oxidation of zirconium in molten salts up to 813–1073 K, the growth of oxide phases is found to proceed chiefly due to the diffusion of oxygen ions via the oxide film toward the metal–oxide interface. An oxide film formed in the initial period of zirconium oxidation in a chloride–nitrate melt decelerates the process but does not prevent the ion exchange at the metal–melt boundary. As the oxide formation proceeds and the steady-state conditions of the corrosion process are reached, the oxidation rate becomes limited by the diffusion of oxygen ions from the film surface deep into the metal. Along with the diffusion of O2frame0 ions at temperatures of 813 to 1073 K, zirconium ions can also migrate in the metal, which makes interpreting the whole process much more difficult. At the oxidation, the films of various colors (from black to light gray) with diverse corrosion and protective properties, as well as fine-dispersed powder of zirconium dioxide with a mean size of particles up to 30 nm, are formed.

PACS numbers: 81.07Wx, 82.45.Qr

DOI: 10.1134/S0033173208030077
03/09/2008 | 921 Посещения | Печать

7.

Multiphase Anodic Layers and Prospects of Their Application

V. S. Rudnev

Institute of Chemistry, Far East Division, Russian Academy of Sciences,
pr. Stoletiya Vladivostoka 159, Vladivostok, 690022 Russia

Received November 1, 2006

Abstract—Information on preparing multiphase layers on valve metals by the plasma-electrochemical oxidation and deposition from aqueous electrolytes containing polyphosphate and fluoride metal complexes, iso- and heteropolyoxoanions, as well as electrolytes evolving solid precipitates, is summarized. Possible application fields of the metal/multiphase PEOD surface structure compositions are considered.

PACS numbers: 82.45.Cc, 81.15.Pg

DOI: 10.1134/S0033173208030089
03/09/2008 | 940 Посещения | Печать

8.

Study of Heteroligand Complex Compounds of Metals with Citric Acid and o-Nitrobenzoylhydrazinein Aqueous Solutions

G. V. Tsintsadze, N. B. Zhorzholiani, I. A. Beshkenadze, and M. A. Gogaladze

 

YuLPP P. Melikishvili Institute of Physical and Organic Chemistry, ul. Dzhikiya 5, Tbilisi 86, 0186 Georgia

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Received October 10, 2007

PACS numbers: 82.60.Hc, 82.80.-d

DOI: 10.1134/S0033173208030090
03/09/2008 | 860 Посещения | Печать

9.

Adsorption Characteristics of Nanoporous Montmorillonite Activated with Orthophosphoric Acid

L. I. Bel’chinskaya*, K. A. Kozlov*, S. S. Chitechan*, A. V. Bondarenko**,
G. A. Petukhova***, and M. L. Gubkina***

 

* Voronezh State Wood Technology Academy, ul Timiryazeva 8, Voronezh, 394613 Russia

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** Lipetsk State Technical University, ul. Moskovskaya 30, Lipetsk, 398600 Russia

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

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Received June 7, 2007

 

Abstract — A comparative effect of the preliminary treatment of lamellar silicate with sulfuric and orthophosphoric acids on the subsequent phenol sorption is carried out. Mechanisms of the phenol adsorption on specimens treated with different acid solutions are found to be different. It is shown that orthophosphoric acid is preferable as an activator of montmorillonite, which can then be used in biochemical decontamination of the sewage of by-product coke industry.

PACS numbers: 68.43.–h

DOI: 10.1134/S0033173208030107
03/09/2008 | 879 Посещения | Печать

10.

Effect of Alcohol on the Corrosion of Al Alloys1 in 1 N H2SO4 Solution Part I

 

A. Buyuksagisa and A. A. Aksutb

a Afyon Kocatepe University, Science and Art Faculty, Afyon,Turkey

b Ankara University Science Faculty, Ankara, Turkey

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Received March 12, 2007

 

Abstract — The aim of this paper is to examine the effects of alcohol (1-buten–3-ol-l, 2-methyl–3-butyn–2-ol, 3-methyl–2-buten–1-ol, 3-methyl–3-buten–1-ol, 3-methyl–1-pentyn–3-ol, 5-hexen–1-ol) on the corrosion of Alalloys. The inhibiting effect of alcohol was investigated by electrochemical current-potential curves, atomic absorption spectrometry (AAS), metal microscopy,SEM and EDS. The results showed that alcohol (1-buten–3-ol, 2-methyl–3-butyn–2-ol, 3-methyl–2-buten–1-ol, 3-methyl–3-buten–1-ol, 3-methyl–1-pentyn–3-ol, 5frame0hexen–1-ol) had an inhibiting effect on the corrosion of aluminium alloys. Experimental results show that corrosion of alloys in H2SO4 solution have been effected by elements in alloys such as Cu, Zn, Mg and adsorp-tion of alcohol on the surface of alloys in H2SO4 solution obeys Temkin adsorption isotherm. The use of alcohol in H2SO4 solution were shifted corrosion potentials (Ecor) to more negative values and acted as cathodic inhibitors on the aluminum alloys. EDS analysis of alloys displayed different intermetallic compounds on the surface of alloys, which might have changed the activity of alcohols depending on the surface morphology of alloys. This paper has showed that these alcohol inhibited corrosion of aluminium alloys in H2SO4 solution. The concentration of 20 mM alcohol was shown that above 90% inhibition was achieved, which is a rather high value.

PACS numbers: 81.65.Kn

DOI: 10.1134/S0033173208030119
03/09/2008 | 867 Посещения | Печать

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