Positron excess,luminous-dark matter unification and family structure

It is commonly assumed that dark matter may be composed of one or at most a few elementary particles. PAMELA data present a window of opportunity into a possible relationship between luminous and dark matter. Along with ATIC data the two positron excesses are interpreted as a reflection of dark matter family structure. In a unified model it is predicted that at least a third enhancement might show up at a different energy. The strength of the enhancements however depends on interfamily mixing angles.     

Observation of a spin gap in the normal state of superconducting Mo3Sb7

Magnetization, specific heat, and electrical resistivity measurements have been performed on the superconductor Mo(3)Sb(7). Two kinds of transitions are observed at 2.3 and 50 K, respectively. The former is superconducting transition, while the latter is attributed to spin-gap formation. From the analysis of the experimental data, excitation gap, intra- and interdimer interactions are estimated as Delta/k(b) approximately 120 K, J(0)/k(B) approximately 150 K, and J(1)/k(B) approximately 55 K. The electronic structure calculations using the LSDA approximation show nesting property in the Fermi surface, favoring the superconductivity.     

Application of citrate-stabilized gold-coated ferric oxide composite nanoparticles for biological separations

Gold-coated magnetic nanoparticles were synthesized with size ranging from 15 to 40 nm using sodium citrates as the reducing agent. Oxidized magnetites (Fe₃O₄) fabricated by co-precipitation of Fe²⁺ and Fe³⁺ in strong alkaline solution were used as magnetic cores. The structures of gold (Au) shell and magnetic core (Au–Fe) were studied by transmission electron microscopy (TEM) image and energy dispersive spectroscopy (EDS) spectrum. Results from high-resolution X-ray diffraction (HR XRD) show that the Au–Fe oxide nanoparticles have a face-centered cubic shape with the crystalline faces of {1 1 1}. The Au-coated magnetic nanoparticles exhibited a surface plasmon resonance peak at 528 nm. The nanoparticles are well dispersed in distilled water. A 3000 G permanent magnet was successfully used for the separation of the functionalized nanoparticles. Magnetic properties of the nanoparticles were determined by magnetic force microscope (MFM) in nanometric resolution and vibrating sample magnetometer (VSM). Magnetic separation of biological molecules using Au-coated magnetic oxide composite nanoparticles was examined after attachment of protein immunoglobulin G (IgG) through electrostatic interactions. Using this method, separation was achieved with a maximum yield of 35% at an IgG concentration of 400 ng/ml.     

Über die Struktur linear kompakter Ringe

Ohne Zusammenfassung     

Systematics of nuclear matter and finite nuclei properties in a non-linear relativistic mean field approach

A phenomenological non-linear relativistic mean field approach is used to investigate primarily the properties of nuclear matter. The dimensionless parameters are adjusted using different empirical quantities which are discussed in detail: saturation conditions, the incompressibility parameter, symmetry energy and surface energy. Particular attention is paid to the cubic and quartic terms in the self-interaction part of the scalar field. The effective parameters are then used to study doubly magic finite nuclei in the Dirac-Hartree approximation. Different ground-state properties, binding energies, rms radii, density distributions, are then systematically analyzed and discussed. A remarkable agreement with experimental quantities is found and further possibilities are suggested.     

Sur la mesure des constantes viscoélastiques des plaques de matériaux composites par les ultrasons

Sans résuméDocteur ès-science, maître de conférence, Laboratoire de Rhéologie I.S.M.C.M., 3, Rue Fernand Hainaut, F-93 Saint-Ouen (France).Avec 3 figures     

Nucleon-alpha potentials

The nucleon-alpha potential is calculated using a microscopic model with antisymmetrisation effects included from Brink and Boeker, Soper and Serber nucleon-nucleon interactions. The energy dependence of the potentials is also derived.     

Role of pore curvature on the thermal stability of gold nanoparticles in mesoporous silica

Pores arranged in a two-dimensional hexagonal structure inside spherical mesoporous silica particles help to prevent the thermal sintering of gold nanoparticles compared to straight pores in MCM-41.