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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 18
1.

A Theory of Pit Initiation. Part I. The Mechanism of Local Depassivation of Metals

Yu. A. Popov

State scientific center of the Russian Federation “Karpov Institute of Physical Chemistry,”
ul. Vorontsovo Pole 10, Moscow, 103064 Russia

Received June 13, 2006

 

Abstract — Electrochemical kinetics at a surface of newly initiated pits is analyzed; the effect of the surface energetical heterogeneity and the self-acceleration kinetics of the surface local depassivation are discussed.

Keywords: pitting, kinetics, potential, self-acceleration, equation, local character, passivity

PACS numbers: 82.45.Bb

DOI: 10.1134/S0033173207030010

09/09/2008 | 851 Посещения | Печать

2.

Conditions and Mechanism of the Ionization and Dissociation of Water. Predictions Based on Nonempirical Calculations

Yu. V. Novakovskaya

Laboratory of Quantum Mechanics and Molecular Structure, Chair of Physical Chemistry,
Faculty of Chemistry, Moscow State University, Leninskie gory, Moscow, 119992 Russia

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Received October 12, 2006

 

Abstract — Based on the results of quantum chemical modeling of neutral and charged water clusters, mechanisms of the ionization and dissociation of water explaining the regularities discovered in experiments are proposed. There are two possible ways of the water and ice ionization, namely, (i) directly from the ground elec-tronic state of the neutral system provided that the high-frequency stretching vibrations of molecules, which determine the formation of H3O+ and OHframe0 ionic fragments, are sufficiently excited, and (ii) via the intermediate transfer to the excited electronic state where hydronium radicals may appear at a certain excess energy. The formation of atomic hydrogen may also take place in the processes of two kinds, namely, (i) the dissociation of the electronically excited water clusters and (ii) the recombination of an electron, appeared upon ionization, with a hydronium cation that leads to the spontaneous detachment of a hydrogen atom. The processes may proceed either successively or simultaneously in a time period compared to the characteristic or even resolution time of the experiment, which may result in incorrect estimation of the quantum yields of hydrated electrons and hydrogen atoms in terms of standard procedures.

PACS numbers: 33.20.Lg; 33.20.Ni; 33.80.-b; 33.80.Rv

DOI: 10.1134/S0033173207030022

09/09/2008 | 746 Посещения | Печать

3.

The Selfconsistency of the Interface Atomic Relief and the Kinetics of Material Exchange between the Solid and Liquid or Gas Phases

Yu. V. Alekseeva, G. Yu. Alekseevb, and V. A. Bityurinb

a Karpov Institute of Physical Chemistry, Vorontsovo Pole 10, Moscow, 103064 Russia

b Institute of High Temperatures, Russian Academy of Sciences, Moscow, Russia

Received September 7, 2005

 

Abstract — Analyzing and clarifying the basic concepts of the statistical method in the theory of material exchange between the solid (ordered) and liquid (disordered) phases noticeably modifies the problem of the metal dissolution and deposition. Taking a surface position of an atom and accordingly the number of its closest neighbors in the phase as an elementary object of statistics, one can derive a system of kinetic equations relating the concentration of diverse positions. Solving the system in a steady-state case provides a selfconsistent description of the topography of the atomic relief and the metal dissolution rate. The problem is solved for a perfect crystal, but the method proposed enables one to formulate and solve the problems of the metal corrosion in the presence of linear and point-wise defects.

PACS numbers: 68.08.-p; 68.35.Ct; 82.45.Jn

DOI: 10.1134/S0033173207030034

09/09/2008 | 870 Посещения | Печать

4.

Specifities of Forming Electrochemical Dissolution Zones at Ferriteframe0Cementite-Structured Alloys in Sulfuric Acid Solutions

N. V. Tarasova and S. N. Saltykov

Lipetsk State Technical University, Lipetsk, Russia

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Received January 13, 2006

 

Abstract —  Specific features of the formation of electrochemical dissolution zones at steels CT20 and CT45 with a ferrite–cementite structure, were revealed by combining electrochemical and metallographic methods. A possibility of developing the self-dissolution process at the ferrite/cementite boundary is shown. A spontane ous sequence of the anodic dissolution of structural constituents of the alloys is found.

PACS numbers: 81.05.Bx

DOI: 10.1134/S0033173207030046

09/09/2008 | 821 Посещения | Печать

5.

New Concept of the Mechanism of Intergranular Corrosion of Stainless Steels

O. V. Kasparovaa and Yu. V. Baldokhinb

 

a State Scientific Center of the Russian Federation “Karpov Institute of Physical Chemistry,”
ul. Vorontsovo Pole 10, Moscow, 103064 Russia

b Semenov Institute of Chemical Physics, Russian Academy of Sciences, ul. Kosygina 4, Moscow, 117977 Russia

Received October 24, 2006

 

Abstract — The electronic structure of chromium–nickel austenite stainless steels of type X20H20 and X10H20, in particular, added with 4 to 6% Si, is studied using nuclear -resonant (Mössbauer) spectroscopy. The structure varies significantly depending on the chromium and silicon content. Low-chromium steels are used for the modeling of chromium-depleted boundary zones that neighbor chromium-rich excess phases. Eventually, a mechanism of the intergranular corrosion of stainless steels that takes into account the changes in the electronic structure of the chromium-depleted boundary zones is first suggested. These changes in the chemisorption interaction of the iron carcass ions with corrosive components of the medium, cannot but affect the zones’ stability. It is this interaction that synergistically intensifius the intergranular corrosion of austenite stainless steels containing combinations of silicon dopant and carbon impurity, or the phosphorus and carbon impurities.

PACS numbers: 33.45.+x; 82.45.In

DOI: 10.1134/S0033173207030058
09/09/2008 | 827 Посещения | Печать

6.

Inhibition of Zinc Dissolution in Borateframe0Sulfate Electrolytes by Benzoimidazoles

V. V. Ekilik, V. V. Chernyavina, and G. N. Ekili

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

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Received March 31, 2006

 

Abstract — The effects of the concentrations of sodium sulfate, benzoimidazole, and its derivatives on active and passive zinc dissolution and local depassivation were studied. The correlations between the effect of substituted benzoimidazoles and the basicity, polarizability, and hydrophobicity were determined.

 

PACS numbers: 81.65.Kn, 82.30.-b

DOI: 10.1134/S003317320703006X
09/09/2008 | 784 Посещения | Печать

7.

The Role of Electrochemical Factors in the Initial Stage of Fatigue-Corrosion Destruction of Stainless Steels

V. I. Pokhmursky and M. S. Khoma

 

Karpenko Physicomechanical Institute, National Academy of Sciences of Ukraine, ul. Naukova 5, Lvov, 79601 Ukraine

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Received April 13, 2006

 

Abstract — The corrosion-fatigue destruction of stainless steels of different classes is studied. It is shown that a decrease in their endurance limit in chloride media is determined by their structure, rather than chemical composition and strength. Based on the electrochemical studies of cyclic-deformed steel samples, their additional deformation dissolution during the period of cracks initiation was calculated. An electrochemical criterion of the susceptibility of corrosion-resistant steels to a corrosion fatigue is suggested and its characteristic analytical formula is derived. The criterion is based on the mutual correlation between the metals’ relative deformationdissolution at the strain equal to the fatigue limit on one hand and the degree of decrease in their endurance under the effect of environment on the other. The occurrence of physical limit of the corrosion fatigue for passive metals is demonstrated. A nondestructive method of determining the corrosion fatigue limit of corrosionresistant steels, based on the change in the sign of polarizing current is developed, and accelerates the tests by a factor of 10–15

 

PACS numbers: 81.65.Kn, 82.20.Wt

DOI: 10.1134/S0033173207030071
09/09/2008 | 817 Посещения | Печать

8.

Protection of Systems with Faulty Sealing by Volatile Corrosion Inhibitors

N. N. Andreev, N. V. Lavrinova, and N. A. Lebedeva

 

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

Received September 7, 2006

 

Abstract — Processes that initiate corrosion in systems with faulty sealing are analyzed in terms of a mathematical model developed to describe metal protection with volatile inhibitors in such systems. It was demonstrated that the protection times are often determined by the kinetics of dilution of an inhibitor with water coming from the atmosphere. The ways of enhancing the vapor-phase protection are proposed. It is found that the effectiveness of a VCI in incompletely sealed systems can be estimated in accelerated tests by decreasing its dosage and increasing the mass exchange surface since these factors stimulate corrosion without violating the similarity principle.

 

PACS numbers: 81.65.Kn

DOI: 10.1134/S0033173207030083
09/09/2008 | 853 Посещения | Печать

9.

Polyfunctional Effects of [1,3]Thiazino[3,2-a]benzoimidazol-4-ones  on Steel Corrosion

V. N. Chelyabievaa, O. I. Sizayaa, S. V. Gatsenkoa, A. N. Esipenkob, and V. N. Britsunb

 

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

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b Institute of Organic Chemistry, National Academy of Sciences of Ukraine, ul. Murmanskaya 5, Kiev, 02660 Ukraine

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Received February 27, 2006

 

Abstract — [1,3]Thiazino[3,2-a]benzoimidazol-4-ones were found to be effective inhibitors of the acid corrosion of steel 20 in 1 M HCl and 1 M H2SO4 (pH 0) and valuable polyfunctional additives that enhance the anticorrosion properties and stimulate the formation of an epoxy powder coating.

 

PACS numbers: 81.65.Kn, 82.30.-b

09/09/2008 | 866 Посещения | Печать

10.

Effects of Arylthio- and Arylseleno(methoxy)methanes on Acid Corrosion of CT3 Steel

I. N. Chernyad’ev, A. B. Shein, and A. N. Nedugov*

 

Perm State University, ul. Bukireva 15, Perm, 614990 Russia

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* Institute of Natural Sciences, Perm, Russia

Received November 29, 2005

 

Abstract — The effects of various arylthio- and arylseleno(methoxy)methanes on corrosion of CT3 steel in sulfuric and hydrochloric acid solutions were studied by gravimetric and voltammetric methods. Some compounds of theses classes were found to be effective inhibitors of the acid corrosion of CT3 steel. The presence of the X–CH2–O–CH3 groups (X = S or Se) in aromatic amines and their derivatives enhanced their inhibitive properties. However, because these groups are highly hydrophobic, the molecules of inhibitors should contain other fragments that ensure sufficient solubility.

 

PACS numbers: 81.65.Kn, 82.30.-b

DOI: 10.1134/S0033173207030101
09/09/2008 | 831 Посещения | Печать

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