The fluxes of CN neutrinos from the Sun in case of mixing in a spherical layer in the solar core

The results of the calculation are presented for the fluxes of CN neutrinos from the Sun in case of mixing in a spherical layer in the solar core, consistent with the seismic data and with the measured solar neutrino fluxes. It is shown that a substantial increase of the flux of $^{13}N$ neutrinos can be gained in this case. The possible implications for experiment are discussed.Comment: 7 pages, 5 figures, minor correction

Superconductivity and Stoichiometry in the BSCCO-family Materials

We report on magnetization, c-axis and ab-plane resistivity, critical current, electronic band structure and superconducting gap properties. Bulk measurements and photoemission data were taken on similar samples.Comment: 4 pages, latex, to be published in Journal of Superconductivity. two figures available from Jian Ma at [email protected]

Phase Behavior of Type-II Superconductors with Quenched Point Pinning Disorder: A Phenomenological Proposal

A general phenomenology for phase behaviour in the mixed phase of type-II superconductors with weak point pinning disorder is outlined. We propose that the ``Bragg glass'' phase generically transforms via two separate thermodynamic phase transitions into a disordered liquid on increasing the temperature. The first transition is into a glassy phase, topologically disordered at the largest length scales; current evidence suggests that it lacks the long-ranged phase correlations expected of a ``vortex glass''. This phase has a significant degree of short-ranged translational order, unlike the disordered liquid, but no quasi-long range order, in contrast to the Bragg glass. This glassy phase, which we call a ``multi-domain glass'', is confined to a narrow sliver at intermediate fields, but broadens out both for much larger and much smaller field values. The multi-domain glass may be a ``hexatic glass''; alternatively, its glassy properties may originate in the replica symmetry breaking envisaged in recent theories of the structural glass transition. Estimates for translational correlation lengths in the multi-domain glass indicate that they can be far larger than the interline spacing for weak disorder, suggesting a plausible mechanism by which signals of a two-step transition can be obscured. Calculations of the Bragg glass-multi-domain glass and the multi-domain glass-disordered liquid phase boundaries are presented and compared to experimental data. We argue that these proposals provide a unified picture of the available experimental data on both high-T$_c$ and low-T$_c$ materials, simulations and current theoretical understanding.Comment: 70 pages, 9 postscript figures, modified title and minor changes in published versio

Specific heat of the high Tc{T_c} organic superconductor κ−(ET)2Cu[N(CN)2]Br\kappa - ({\rm ET})_2{\rm Cu[N(CN)}_2]{\rm Br}

No abstract availabl

Achieving high strain rate superplasticity in Al-Mg-Sc-Zr alloys after severe plastic deformation

The application of severe plastic deformation to metallic alloys via the procedure of equal-channel angular pressing (ECAP) leads to significant grain refinement and an opportunity for achieving superplastic deformability at very high strain rates (10–2 s–1). The development of high-strain-rate superplastic alloys is important because it provides the possibility for making use of superplastic forming for the rapid fabrication of complex components. Experiments were conducted to evaluate the mechanical properties of a series of Al–Mg– Sc–Zr alloys after ECAP. The results demonstrate that some of these alloys exhibit exceptionally high tensile ductilities (elongations up to &gt; 2000%) at very rapid strain rates.<br/

On a Possible Reason of Tc\mathsf{_c} Suppression with Oxygen Doping in Tl2\mathsf{_2}Ba2\mathsf{_2}CuO6+x\mathsf{_{6+x}}

Magnetic susceptibility and $^{63}$Cu and $^{205}$Tl nuclear spin-lattice relaxation rates have been measured in Tl$_2$Ba$_2$CuO$_{6+x}$ high-temperature superconductor to establish the mechanism of decreasing the transition temperature with oxygen doping. The experiments have revealed the presence of localized paramagnetic centers (LPC) whose concentration grows with increasing oxygen content. These centers can give rise to magnetic scattering of the Cooper pairs and thus be responsible for the $T_{\rm c}$ suppression. This assumption is supported by the pair-breaking effects observed in the NMR Knight shift and relaxation rate behavior in the superconducting state