Индекс цитирования

Авторизация






Забыли пароль?

Обложка журнала

НОВОСТИ

(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...
Read More ...
(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...
Read More ...
(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...
Read More ...
(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...
Read More ...

Ссылки

Нанометр


 

Результаты 1 - 10 из 118
1.

Chemical Deposition of Nanostructured Tungsten and Tungsten-Alloy Coatings from Gas Phase

Yu. V. Lakhotkin

Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences,
Leninskii pr. 31, 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 5, 2007

Abstract — The historical overview of the fluoride method for the low-temperature deposition of tungsten, its  alloys, and compounds in Russia is presented. The physicochemical fundamentals (thermodynamics, kinetics) of the deposition process are given. The most probable rout for homogeneous and heterogeneous reactions resulting in the formation of the tungsten metal at the substrate surface is theoretically substantiated. Based on  the experimental study of the initial crystallization stages, a basic mechanism of the active growth centers for-mation is formulated. Kinetic characteristics of the processes of tungsten codeposition with refractory transition metals, as well as the coatingsí physical-mechanical properties are given. Data on the deposition of solid tungsten-carbide films from gas phase onto low-temperature substrate are reported. Possible applications of the tungsten, tungsten alloys with transition metals, and tungsten carbide coatings are discussed.

PACS numbers: 81.16.Fg

DOI: 10.1134/S0033173208040024
03/09/2008 | 762 Посещения | Печать

2.

Chronovoltammetry of the Anodic Dissolution of Agframe0Au Alloys in Nitrate Environments

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

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

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

Received April 4, 2007

Abstract — A theory of quasi-reversible anodic chronovoltammetry of the selective dissolution of a homogeneous A–B alloy controlled by the solid-phase diffusion is proposed. The effects of the equilibrium solid-phase adsorption of the components and the roughness of the electrode surface with either homogeneously or statistically normally distributed microscopic irregularities of diverse kind on the shape of chronovoltammogram (the IA current dependence on the (t) overpotential) are successively taken into account. An expression for the IA,m current at the voltammogram maximum, which is a generalization of the Randles–Sevcik formula, is derived. A technique of estimating the recording-time boundaries of voltammograms, within which the surface roughness effect may be taken into account by simply multiplying the current by the roughness factor fr, is founded. Outside the time interval, the IA,m frame1 1/2 dependence ( is the potential scanning rate), which is criterion for the diffusion kinetics, is shown to be substantially nonlinear. The diffusion-zone parameters ( thickness and DAg heterodiffusion coefficient) obtained by processing the experimental data for Ag–Au alloys with a gold content of 15 or 20 at. % with the use of three models discussed are compared.

PACS numbers: 82.45.Qr

DOI: 10.1134/S0033173208040036
03/09/2008 | 815 Посещения | Печать

3.

 

 Thermodynamics of the Adsorption of 4-Nitrophenol from Aqueous Solutions at Activated Charcoal

O. K. Krasil’nikova, T. A. Kul’kova, and A. V. Larin

Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, eninskii pr. 31, 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 June 26, 2007

Abstract — The adsorption of 4-nitrophenol from aqueous solutions at activated FAS-1 charcoal was studied at

293, 308, 318, and 328 K. The experimental data obey the Dubinin–Astakhov–Stoeckli equation (a special case of the Dubinin–Radushkevich equation) for different exponents n. For experimental adsorption isotherms, the characteristic curve of the micropore volume filling theory was not temperature-invariant. However, these adsorption isotherms were described by the Dubinin–Radushkevich equation with n = 8 over a wide concentration range. This satisfacry description and the nonlinearity of the adsorption isotherms in the Dubinin–Asta-khov–Stoeckli coordinates (for different n values) for low filling values are probably associated with competitive adsorption of water and 4-nitrophenol molecules in small micropores of the adsorbent. The calculated isos-teric heats of adsorption increase with the adsorbed amount, which is also the case that the characteristic curve is not temperature-invariant.

PACS numbers: 68.43.-h

DOI: 10.1134/S0033173208040048

 

 

03/09/2008 | 820 Посещения | Печать

4.

Anodic Oxidation of Ag-Cu Alloys in Sulfuric Acid Solutions When Reaction Products are Unstable

A. V. Noskov, E. P. Grishina, and A. M. Pimenova

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

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

Received July 6, 2007

Abstract — Based on the impedance models of porous layer, anodic behavior of silver as a component of Ag–Cu alloys in aqueous sulfuric acid solutions is analyzed. It is shown that, in order to adequately describe the electrochemical process, chemical decomposition of superficial passivating silver-sulfate layer should be taken into account. Decomposition rate constants of the layer on silver–copper alloys of diverse composition are cal-culated.

PACS numbers: 82.45.Bb, 81.15Aa

DOI: 10.1134/S003317320804005X

03/09/2008 | 815 Посещения | Печать | Подробнее ...

5.

FTIR Spectroscopic Studies of Interactions of Stilbenes with Silicon Dioxide

K. E. Polunin, N. P. Sokolova, A. M. Gorbunov, R. A. Bulgakova, and I. A. Polunina

Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences,

Leninskii pr. 31, 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 June 26, 2007

Abstract—Adsorption interactions of trans-stilbene and its hydroxy and methoxy derivatives with the surface of nanodispersed SiO2 aerogel were studied by diffuse-reflection FTIR spectroscopy. Stilbenes were found to adsorb at the aerosil via hydrogen bonding to silanol OH groups. The deepest modification of these groups was produced by 3,5,4'-trihydroxystilbene (resveratrol). Although the stilbenes adsorbed reversibly, the absorption spectra of the starting and desorbed resveratrol proved to differ. UV irradiation ( = 285–305 nm) of adsorbed hydroxystilbenes changed the composition and properties of adsorbed layers. The changes include breaking of the hydrogen bonds between the hydroxystilbene molecules and the surface, destruction of the stilbenes involving cleavage of the double bond of the ethene fragment, dimerization, oxidation, and transformation into other compounds. The intensity of heterogeneous photolysis depends on the number and composition of functional groups in trans-stilbenes.

PACS numbers: 68.43.-h

DOI: 10.1134/S0033173208040061

03/09/2008 | 850 Посещения | Печать | Подробнее ...

6.

Heterogeneous Distribution of Adsorbed Water Molecules in NaX Zeolite Nanopores from the Data of Positron Spectroscopy

I. I. Bardyshev and A. A. Fomkin

Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences,

Leninskii pr. 31 / 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 June 26, 2007

Abstract — Adsorption techniques and positron annihilation method showed that the actual distribution of adsorbed water molecules in micropores of a crystalline NaX zeolite is substantially heterogeneous. Under atmospheric conditions when the whole micropore volume is thought of as filled with water, the main part of water molecules is found to be involved in the solvation shells of sodium cations, so that a substantial part of micropore volume, about 30%, remains free.

PACS numbers: 68.43.-h

DOI: 10.1134/S0033173208040073

03/09/2008 | 923 Посещения | Печать | Подробнее ...

7.

Synthesis of Carbon Nanomaterials with Porous Alumina as a Template

O. K. Krasil’nikova, A. S. Pogosyan, N. V. Serebryakova, T. Yu. Grankina, and A. N. Khodan

Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences,

Leninskii pr. 31, 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 October 12, 2007

Abstract — Single- and double-walled carbon nanotubes were obtained by template synthesis with foamed monolithic alumina as a template. The carbon materials obtained are homogeneous; their structures depend on the carbon precursor used. Double-walled nanotubes (with saccharose as a carbon precursor) have an average diameter of about 0.4 nm and a specific surface area of about 400 m2/g (from the BET isotherm). Single-walled carbon nanotubes (with a polymer based on furfuryl alcohol as a carbon precursor) have a diameter of 1.8 nm and a specific surface area of 580 m2/g.

PACS numbers: 68.43.-h

DOI: 10.1134/S0033173208040085

03/09/2008 | 864 Посещения | Печать | Подробнее ...

8.

The Effect of the Structure-Phase State of Iron-Cementite Nanocomposites on Local Activation Processes

A. V. Syugaev*, S. F. Lomaeva*, S. M. Reshetnikov**, A. S. Shuravin**,

E. F. Sharafeeva**, and D. V. Surnin*

*Physicotechnical Institute, Ural Division, Russian Academy of Sciences, ul. Kirova 132, Izhevsk, 426000 Russia

**Udmurtia State University, Universitetskaya 1, Izhevsk, 426034 Russia

Received June 21, 2007

Abstract — Studies of the local activation of iron–cementite nanocomposites (NC) revealed the step-wise increase in their resistance to pitting with an increase in the Fe3C content (~50 mass %) or with the formation of an ordered cementite network structure. The corrosion process is determined by the chemical state of carbon, namely, free or bound into carbides. The free carbon evolution leads to depassivation and the transition to structure-selective corrosion

PACS numbers: 81.07.Bc, 82.45 Bb

DOI: 10.1134/S0033173208040097

03/09/2008 | 837 Посещения | Печать | Подробнее ...

9.

Synthesis and Properties of Nickel Nanoparticles and Their Nanocomposites

S. V. Gornostaeva*, A. A. Revina**, L.D. Belyakova**, and O. G. Larionov**

*Mendeleev University of Chemical Engineering, Miusskaya pl. 9, Moscow, 125057 Russia

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

119991 Russia

Received July 2, 2007

Abstract — For the first time, nickel nanoparticles are synthesized in reverse micelles by a radiation-chemical method. The particles are shown to be spherical with sizes of an order of magnitude of 1–100 nm. Nickel particles are oxidized by air oxygen to nickel oxide nanoparticles, retaining their shape and nanoscale dimensions. Adsorption of nickel-metal nanoparticles on silica is studied by spectrophotometry.

PACS numbers: 68.43.-h

DOI: 10.1134/S0033173208040103

03/09/2008 | 807 Посещения | Печать | Подробнее ...

10.

The Effect of Heat Treatment on a Feframe023%Cr Alloy Hyperfine

Structure and Passivability

O. V. Kasparovaa, Yu. V. Baldokhinb, G. F. Potapovaa, and M. O. Anosovac

a FGUP State scientific center of the Russian Federation “Karpov Institute of Physical Chemistry”, ul. Vorontsovo Pole 10,

Moscow, 105064 Russia; e-mail: Этот e-mail защищен от спам-ботов. Для его просмотра в вашем браузере должна быть включена поддержка Java-script

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

c Moscow Institute of Steel and Alloys, Leninskii pr. 4, Moscow, 117936 Russia

Received April 18, 2007

Abstract — The stability of the passive state of a Fe–23%Cr alloy in 1 N H2SO4 solution at room temperature was studied as a function of the impurity-elements content and the heat treatment conditions, in particular, the quenching and ageing at 475frame1C (200 h) and 650frame2C (10 and 100 h). The alloys hyperfine structure was studied using Mössbauer spectroscopy. The observed cases of the passive state disturbance are explained by the solid solution separation (after the ageing at 475frame3C) and the chromium-based second precipitation during the quench cooling and ageing.

PACS numbers: 76.80.+y, 82.45.Bb

DOI: 10.1134/S0033173208040115

03/09/2008 | 804 Посещения | Печать | Подробнее ...

<< [Первая] < [Предыдущая] 1 2 3 4 5 6 7 8 9 10 [Следующая] > [Последняя] >>
  

Powered by AlphaContent 3.0.4 © 2005-2017 - All rights reserved