No abstract available

[en] Full text: Many groups of Latvian University scientists are participants in European Fusion Development Agreement projects. This work needs good contacts with other groups. With purpose of saving time and money EFDA develops different remote participation facilities, using information technologies and progress in high speed Internet accessibility. Some remote participation methods possibly will be demonstrated

No abstract available

[en] Full text: The interacting boson model (IBM-1) is characterized by several groups of symmetry -U(5), SU(3), SU(3)'', O(6), corresponding in the limiting cases of this model to the definite nuclear shape (spherical, prolate and oblate axially symmetric deformed, triaxial). The precise analysis of the extended Casten triangle version of IBM-1 for the classical energy functional E(N, ^eta^, χ, β) has been performed according to the phase transition theory, and the conditions on model parameters for the transitions between nuclear shapes and for the coexistence between shapes has been studied

[en] Full text: Condensed matter is able to accumulate light energy in excited (ionised) luminescence centres from which electrons or holes are realized and localized in the traps. These active centres may be impurity atoms (ions) or intrinsic defects. Light energy accumulation occurs when luminescence centres are excited by radiation able to realise electrons or holes from centres. In traps localized electrons or holes can be realised from them by rising temperature or infrared irradiation. Light emission occurs when from traps realised electrons or holes return to the excited luminescence centres. From practical viewpoint it is necessary to increase the concentration of active centres in the condensed matter. To use this substance as light accumulator, it will be necessary to convert practically all atoms in the condensed matter to active centres

[en] Full text: Particle sizing problem arises in many fields of science, technology and material production. Methods based on X-ray diffraction lines broadening cover size interval of 10-100 nm and are well documented. Larger crystallites demonstrate no line broadening and require alternative methods for size determination. When crystallites are relatively large (10-500 mkm) and a small volume of the sample is irradiated the diffraction pattern exhibits discrete spots instead of continuous diffraction lines. We base our approach on the linear correlation between average crystallite's size and diffraction spots dimensions which is valid for crystallite size above 5 mkm. Thus the aim of this work is to extract the crystallite size distribution function from the analysis of the spot size distribution

[en] Full text: Al and Cu coatings on glass, copper and steel substrates were obtained by the method of a rotating wire brush. Such a treatment makes both cutting out metal particles from bulk metal specimen and transferring them to the substrate in conditions of severe dynamical shear deformation. At the micro level, the scheme of deformation is similar to that for the friction test. The procedure is performed in air and involves intensive oxidation of transferred metal particles. The results of secondary ion mass spectrometry (SIMS) show the presence of oxygen compounds of metals practically throughout the coating. The AFM and X-ray diffraction studies of coatings showed that transferred metals have a nonhomogeneous, thermally stable nano structure with a grain size from 30 to 200 nm. The microhardness of the coatings was by a factor of 8-10 higher than that for the source metals. The coatings show high adhesion and good wear resistance. Such properties are determined by nano structure of coatings, stabilized by the presence of oxide interlayers

[en] Full text: X-ray absorption spectroscopy (EXAFS and XANES) provides with unique information on electronic, atomic and dynamic structure of materials. Standard EXAFS and XANES analysis is based on relatively simple structural models as Gaussian / normal distribution. However, there are many compounds as glasses and nanocrystalline materials in which atoms of the same type occupy structural sites with different local environments. Therefore, special approach is required to access properly the case of configurational disorder. In this work we present recent developments for such problem

[en] Full text: The development of III-V group nitride materials is of considerable interest for semiconductor electronic and optical device applications. The band gaps of III-V group nitrides range from 1.9 eV for wurtzitic InN to greater than 6.2 eV for cubic BN, making these materials well suited for optical applications throughout the visible and into the near-UV region. Investigation of BN thin film cathodoluminescence has been performed. Thickness of BN thin film received from Rostock colleagues was 0.77 μm, and was grown on Si substrate. Cathodoluminescence of BN thin film characterizes with dominant luminescence band at 330 nm and some other less intensive luminescence bands. The same bands are observed in spectra of photoluminescence and they are typical for hexagonal structures of BN. In further research it is recommendable to perform investigations on thicker BN films to obtain more intensive luminescence for precise and detail determination of luminescence parameters

[en] Full text: Nowadays, there is paid a big attention to researches related to new energy sources and renewable energy usage in entire world. However, the investigation problem also concerns to energy storage, transport, usage, hereto, all process has to be as cheep and easy as possible. Hydrogen energy is one of the leading and most promising investigation objects. Metalhydrides are materials with very suitable qualities for hydrogen absorption, storage and desorption. There is important to know and investigate characteristics, kinetics and thermodynamics of new metalhydride alloys to comparison with known, classical ones, because of possible better processes and cheaper obtaining. In this work was investigated hydrogen absorption - desorption rate and amount of La rich metal (Mm) in comparison to the same metalhydride composite with other materials (SiO₂, C, WO₃, B₂O₃) by using thermogravimetric balance. Experiment in the same way was repeated just with change material. Gained data was treated and conclusions were made