<Emphasis Type=Italic>Y</Emphasis> and <Emphasis Type=Italic>Z</Emphasis> luminescence of polycrystalline cadmium telluride

The properties of polycrystalline CdTe with a grain size of 5–30 μm have been investigated using the microphotoluminescence methods of spectral analysis and topography. This material has been prepared by direct synthesis in a vapor flow of components at a low temperature. The dominance of the Y and Z bands in the spectra reflects a nonequilibrium character of the crystallization processes. The superlinear dependences of the luminescence intensity on the level of the band-to-band excitation indicate the exciton nature of the corresponding transitions. The activation energies for temperature quenching of luminescence in the temperature range T = 100–150 K are found to be 120 meV for the Y luminescence and 180 meV for the Z luminescence, which correspond to the dissociation of excitons bound to defects with the transition of charge carriers to the conduction and valence bands. The monochromatic topography data indicate that Y and Z defects have different material bases.     

Cosmology based on <Emphasis Type=Italic>f</Emphasis>(<Emphasis Type=Italic>R</Emphasis>) gravity with <Emphasis Type=Italic>O</Emphasis>(1)eV sterile neutrino

We confront different up to date cosmological data with different gravity models of the Universe with one additional massive sterile neutrino [1].     

Static spherically symmetric solutions in <Emphasis Type=Italic>F</Emphasis>(<Emphasis Type=Italic>R</Emphasis>) gravity

A Lagrangian derivation of the Equations of Motion (EOM) for static spherically symmetric metrics in F(R) modified gravity is presented. For a large class of metrics, our approach permits one to reduce the EOM to a single equation and we show how it is possible to construct exact solutions in F(R)-gravity. All known exact solutions are recovered. We also exhibit a new non-trivial solution with non-constant Ricci scalar.     

<Emphasis Type=Italic>T</Emphasis>-solutions of different types and their relations to <Emphasis Type=Italic>R</Emphasis>-solutions

Different types of T-solutions are investigated. The conditions at which one region of space-time can be described only by a statistic R-solution and another region can be described only by a T-solution are obtained. The common metric for R- and T-solutions is obtained where the spatial and temporal variables are interchanged. The T-solution which has the same mass function as for the internal static Schwarzschild solution is obtained.     

Idempotents as <Emphasis Type=Italic>J</Emphasis>-Projections

Let B(H) ^Id be the set of all bounded idempotents on a Hilbert space H. Fix p∈B(H) ^Id . The aim of the paper is to show a set of symmetries J on H for which p is a J-projection.     

Unitarity of the tree approximation to the Glauber <Emphasis Type=Italic>AA</Emphasis> amplitude for large <Emphasis Type=Italic>A</Emphasis>

The nucleus-nucleus Glauber amplitude in the tree approximation is studied for heavy participant nuclei. It is shown that, contrary to previous published results, it is not unitary for realistic values of nucleon-nucleon cross sections.     

Astrophysical <Emphasis Type=Italic>S</Emphasis>-factor of radiative <Emphasis Type=Italic>p</Emphasis><Superscript>6</Superscript>Li capture at low energies

A possibility of describing experimental data for the astrophysical S-factor of p⁶Li capture at low energies is discussed within the potential cluster model with forbidden states.     

Anisotropic distributions of electrical currents in high-<Emphasis Type=Italic>T</Emphasis><Subscript><Emphasis Type=Italic>c</Emphasis></Subscript> grain-boundary junctions

We developed a self-consistent method for the calculation of spatial current distributions in high-T _c grain-boundary junctions. It is found that crystallographic anisotropy of high-T _c superconducting electrodes results in the effects, which previously were not taken into account for interpretations of experimental data. Among them is a significant redistribution of electrical currents in superconducting electrodes in the vicinity of a grain boundary. In particular in the case of [100]-tilt bicrystal junctions, this current redistribution results in a substantial focusing to the top or bottom part of a thickness of the grain boundary, depending on “roof”- or “valley”-type of the grain boundary. This redistribution is accompanied by generation of vortex currents around the grain boundary, which leads to self-biasing of grain-boundary junctions by magnetic field nucleated by these vortex currents. It is shown that twinning or variation of geometrical shape of the high-T _c electrode may also result in intensive redistribution of electrical currents and nucleation of local magnetic fields inside a high-T _c superconducting electrodes.