Fe-doped AlN nanorods were studied by means of x-ray absorption spectroscopy above the Fe K- and L2,3- edges. Theoretical simulations of the x-ray absorption spectra show that Fe atoms mainly substitute Al. A minor fraction of Fe interstitials or Fe-Al-N ternary alloy can be identified as well. Bader’s AIM analysis predicts that neutral substitutional FeAl defect is in 2+ charge state, though Al in pure AlN is in 3+ charge state. Fe L2,3 absorption spectra and photoluminescence data indicate the coexistence of Fe2+/Fe3+ in AlN:Fe nanorods so different charge states of substitutional FeAl should co-exist.
Keywords: diversification of management, production diversification, financial and economic purposes of a diversification, technological purposes of ensuring flexibility of production
In this paper we study of the local atomic and electronic structure of nanostructured condensed material for rechargeable current sources on the basis of 15mas.%V2O5/Fe/LiF nanocomposite within charge-discharge cycle. Principle component analysis (PCA) of the series of Fe K-edge spectra collected during 1 st charge showing the concentrations of the components Fe, FeF2 and V[FeV]O4. We found the changes in the V oxidation state from the analysis of the experimental Fe K- and V K- XANES spectra. Total and partial density of states of components are presented.
Keywords: nanostructured materials for rechargeable current sources, dynamics of local atomic and electronic structures, XANES, DFT
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)
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
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