Alzheimer's disease is an incurable illness. It affects about half a million people in Russia, and due to the general trend towards aging of the population the number of Alzheimer's disease cases will steadily increase. Insoluble deposits of amyloid beta in the brain tissue (amyloid plaques) are the major morphological characteristic of Alzheimer's disease. It has been found that the increased concentration of copper in amyloid plaques results in copper ions bound to the protein. It is the presence of copper in the binding site triggers of the formation of amyloid plaques. Therefore, the study of the binding site in amyloid beta is of great scientific interest. The local atomic structure of the Cu(I) copper ion binding site in the amyloid beta peptide has been studied by means of XANES spectroscopy. Several model structures obtained by molecular mechanics and density functional theory (ADF code) have been tested. Theoretical analysis of X-ray absorption spectra based on the finite difference method implemented in FDMNES code was performed. An appropriate model structure of the Cu(I) copper ion binding site in amyloid beta peptide has been found.

Keywords: amyloid beta, binding site, Alzheimer's disease, the method of finite differences, Cu(I)

We study the problems in the propagation of acoustic waves of a sound range near the boundaries of media. The features of the wave processes occurring at the water-air interface, due to the influence of inhomogeneous waves. Considered in detail the properties and parameters of an inhomogeneous plane wave. The mathematical calculations of the transmission coefficients L.M. Brekhovskikh for spherical and cylindrical waves through this boundary, allowing to take into account the contribution of inhomogeneous components. It is shown that than the frequency of radiation of a source is lower and the closer it is located to water-air interface, the acoustic transparency of this border is higher. Study of the dependence of the transmission coefficient of the water-air interface at low frequencies can have important consequences in a number of fundamental and applied problems. Increase the transparency of the interface requires a reassessment of the feasibility of acoustic communication from water in the air, the detection of underwater sources without dipping into the water and acoustic monitoring of the physical processes occurring in the water.

Keywords: Inhomogeneous plane wave, water-air interface, transmission coefficient, wavelength, spherical wave, acoustic impedance.

This paper describes an in-situ experimental technique to study of ceria nanocatalysts by using X-ray absorption near edge spectroscopy XANES. This technique allows us to determine Ce3+ concentration inside ceria nanoparticles in the course of catalytic reaction based on the comparison and divergence minimization of the Ce L3 XANES spectrum of the ceria nanoparticles under catalysts (atmosphere, temperature) with a linear combination of two independent components corresponding to spectra of Ce4+ ion of the CeO2 structure and Ce3+ ion of the theoretical Ce2O3 structure. The calculated weight ratio determines the Ce3 + concentration in the sample during the catalytic reactions.

Keywords: in-situ X-ray absorption spectroscopy, HERFD, XAS, ceria nanoparticles, Ce-based catalysts, Ce3+ concentration

Solution for high-speed video transmission in hydroacoustic channel by amplitude modulation with orthogonal subcarriers is specified. Results of method experimental check are presented. Discussed method is doppler-tolerant and can be realized in many common DSPs.

Keywords: hydroacousitcs, video transmission, amplitude modulation

The analysis of temperature dependence of frequencies of lines  is conducted active in the spectrums of combination dispersion of  perchlorate of natrium. The theory analysis of spectrums is conducted.

Keywords: Perchlorat of natrium, anion, spectrums of combination dispersion, phase change

Information about authors of issue №4 (2013)

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The article gets application multi-element piezoelectric transducers for ultrasonic high-speed flaw  detection on railway tracks. The processing algorithm of echo-signals from multi-element piezoelectric transducers was offered to get additional information about defect location to apply solution considering risk level more validly and to increase crack detection probability. The obtained algorithm was realized as software package. A set of experiments was completed for fourth-elements inclined piezoelectric transducer on a standard pattern for various positions to verify the processing algorithm. The experiment has shown that the echo-signals behavior allows to use the obtained algorithm for multi-element transducers at the high-speed flaw detection. Also it has emerged that the echo-signal shape at one element of piezoelectric transducer strongly depends on refracting prism geometry and relation position elements on prism.

Keywords: multielement piezoelectric transducers; ultrasonic methods; echo-signal; high-speed flaw detection

  This paper discusses the problem of controlling the characteristics of sonar multibeam receiver antennas. Hydro acoustic means, such as side-scan sonar, profiler, sonar, multibeam sonar, are used extensively for remote determination of the parameters of media for environmental management. In the article the technique of controlling the phase-frequency characteristics of the receiving antennas multibeam echoes sounders. The study method allows the measurement of the phase-frequency characteristics of antennas in a hydro acoustic tank which size is less than length of a near field of the reception aerial.

Keywords: Conservancy, multibeam echo-sounder, seabed research, underwater acoustic

The values  the frequencies of the stretching vibrations of anions  SCN-,  NO2-, NO3-, CℓO4- in molten salts of alkali metals and their point group symmetry. There is a correlation with an increase in the frequency of symmetry  

Keywords: Raman Spectra; anions; molten solts; group symmetry.

In this paper we study the dynamics of the local atomic structure of new nanostructured condensed material for for rechargeable current sources on the basis of 15mas.%V2O5/Fe/LiF nanocomposite within charge-discharge cycle on the basis of X-ray diffraction (XRD), X-ray absorption spectroscopy (XANES) and of computer simulation. The analysis of the experimental data obtained during the first charge cycle reveals the transformation of iron to more than 50% of iron fluoride (II) , Li ions intercalate into the structure of amorphous V2O5 forming LiVO2 compound.

Keywords: diversification of management, production diversification, financial and economic purposes of a diversification, technological purposes of ensuring flexibility of production

Combined method which allows analyzing parameters of the nanoscale atomic and electronic structure of materials relying on three different methods (x-ray absorption spectroscopy (XAFS), x-ray diffraction (XRD) and Raman spectroscopy) was developed. The method was applied for the study of nickel oxide nanoparticles, which serve as an efficient catalyst for the artificial photosynthesis process. 

Keywords: solar energy, artificial photosynthesis, NiO, Raman, x-ray diffraction, XAFS

We have carried out the analysis on the scientific and technological literature on methods of calculation and analysis of the x-ray diffraction, x-ray absorption and Raman spectra used to analyse the structure of the materials for hydrogen storage under realistic operating conditions. The simulations were carried out for the series of small palladium nanoclusters with embedded hydrogen. Multiscale computer modelling was used to simulate the dynamics of structure of the materials during charge/discharge phases.

Keywords: hydrogen storage, XANES, x-ray diffraction, Raman scattering, fuel cell

Information about authors of issue №2 (2013)

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Information about authors of issue №4 p.2 (2012)

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Information about authors of issue №4 p.1 (2012)

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