225 research outputs found
Peculiarities of training foreign students in the masters program «International business in the field of trade and services»
Nowadays more and more foreigners choose Russia as a country where they can get education in a prestige University, knowledge o f Russian being not obligatory. Thus, to deliver lectures for foreign students Russian specialists should both professionally master English and consider their national and vocational peculiaritiesВ последние годы все больше иностранных граждан выбирают Россию в качестве страны, где можно получить образование в престижном университете, причем без знания русского языка. В этой связи для российских преподавателей важным является не только хорошее владение английским языком, а также профессиональных и национальных особенностей магистранто
Effect of anodic oxygen evolution on cell morphology of sulfuric acid anodic alumina films
The purpose of this work was to study and analyze the effect
of electrolyte temperature and anodization voltage on cell morphology
of thin films of sulfuric acid anodic alumina formed on substrates of
different nature, such as SiO2/Si, glass-ceramic, glass substrates, and
polished aluminum. The data obtained demonstrated that the thermal
conductivity of the substrate in the voltage range from 12 to 14 V
affected a pore diameter (dpore) in anodic films. Depending on the
substrate type, dpore increased in the following order: glass > glass-
ceramic > SiO2/Si > aluminum. It was found that the anodizing voltage
(Ua) of 16 V was a turning point for anodic films obtained in sulfuric
acid after which the slope of the lines for both dpore and Dinter
(interpore distance) vs. Ua changed. This behavior might be explained
by the occurrence of the overpotential enough for the beginning of the
oxygen evolution reaction. We assumed that the oxygen evolution on
aluminum oxide surface at the pore bottom at Ua> 16 V results in an
increase in acid concentration in the solution and, consequently, in rise
in acidic nature of the electrolyte and increase in the dissolution rate of
the oxide layer of pore walls
Photoluminescence and its damping kinetics of nanoporous alumina m embranes formed in solutions of various carboxylic acids
The article is devoted to the study of the photoluminescence of carbon-containing anodic alumina obtained in various electrolytes based on carboxylic (tartaric and oxalic) acids. We studied the emission and excitation spectra of luminescence, as well as the PL decay of nanostructured anodic alumina membranes. It is shown that such membranes exhibit photoluminescence (excitation wavelength 330 nm) in the wavelength range 350-600 nm with a maximum at 460 nm. They have two PL centers with maxima at 440 and 490 nm and lifetimes of 0.2 and 4.0 ns, respectively. It is shown that the PL peak at 440 nm can be related to the emission of COO– - ions, and the peak at 490 nm can be related to the PL of defects in partially oxidized amorphous carbon
The sorption of water molecules in the pores of anodic alumina films during aluminum anodizing in oxalic acid
The thermogravimetric analysis of membranes of anodic aluminum oxide (AAO) was carried out. The results showed that in the process of anodic growth, water molecules are adsorbed in the pores of Al2O3, the amount of which is determined by the anodizing voltage of aluminum. The relationship is revealed and the graphs of the relationship between anodizing voltage, annealing temperature, and weight loss of nanostructured membranes of AAO are presented. It has been established that the adsorption of water molecules on the surface of AAO is explained by the presence of a surface charge, which disappears after annealing at 200–300 °C. An increase in the amount of adsorbed water with an increase in the anodizing voltage from 20 to 40 V indicates a decrease in the surface charge density
Stored charge and its influence on properties of anodic alumina films
In porous and barrier-type anodic alumina films, the stored charge has electronic nature and it plays a significant role in the process of aluminum anodizing. The charge stored can modify the distribution of local field generated by a voltage applied and thus it can affect the oxide growth. The method for the investigation of thermally activated defects in anodic alumina films by reanodizing technique was also described. It was applied for computation of activation energy of electron traps in barrier layer for sulfuric and oxalic acid alumina films and concentration of the traps
Investigation of the features of the porous morphology of anodic alumina films at the initial stage of anodization
The work is devoted to the study of the porous structure formation of anodic alumina films at the initial stage of aluminium anodizing. SEM images of the surface morphology of the oxalic acid anodic films were analyzed. It was shown that at the initial stage, both major and minor pores are formed, the diameter ratio of which is about 1.16 and does not depend on the anodizing voltage. The results obtained indicate that the minor pores in the anodic films are located inside hexagonal cells composed of the major pores
Scientific Performance of the ISDC Quick Look Analysis
The INTEGRAL Science Data Centre (ISDC) routinely monitors the Near Real Time
data (NRT) from the INTEGRAL satellite. A first scientific analysis is made in
order to check for the detection of new, transient or highly variable sources
in the data. Of primary importance for this work is the Interactive Quick Look
Analysis (IQLA), which produces JEM-X and ISGRI images and monitors them for
interesting astrophysical eventsComment: 4 pages, 3 figures. Proceedings of 5th INTEGRAL Workshop: The
INTEGRAL Universe, Munich, 16-20 February 2004. Accepted for publication in
European Space Agency Special Publication 552. See paper for institute
affiliation
Study of microstructure of porous anodic alumina films formed in malonic acid in the wide range of aluminium anodizing voltages
In present paper the microstructure parameters of porous anodic alumina films formed by the anodizing of aluminum in the aqueous solution of malonic acid at different anodizing voltages was studied. The morphology of structured surface of aluminum film was studied using a scanning electron microscope after selective removal of anodic film. The results obtained for anodic films formed in malonic acid during anodizing in the range of 15-80 V allowed to determine that change in the interpore distance with the anodizing voltage is linear function with a slope of 1.45. The key conclusion was made that mechanical stress in anodic alumina layer is the main factor responsible for formation of the nanoporous structure of anodic alumina films
Monitoring of Electrode Temperature in Exothermic Electrochemical Process
In this paper the features of temperature control of aluminum electrode during the anodization are discussed. Temperature monitoring in this exothermic process is a necessary condition for obtaining a high ordered nanoporous structure. A new electrochemical cell with a Peltier device working in cooling or heating mode was proposed. Time dependences of the electrolyte and Peltier element temperatures without and during anodizing process were presented. The results demonstrated that the cell construction allows precise control of the electrode temperature
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