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  1. Structural instability in single crystals of the high-T/sub c/ superconductor La/sub 2-//sub x/ Sr/sub x/ CuO/sub 4/

    Single crystals superconducting La/sub 2-//sub x/Sr/sub x/CuO/sub 4/ (xapprox.0.08)= have been investigated in the temperature range 15--298 K and are found to undergo a structural phase transition below room temperature, but above 180 K. Detailed analysis of the diffraction-peak profiles obtained below the transition temperature indicates a breakup of the macroscopic crystals into multiple domains of different orientations. Several cooling and warming cycles always reverse the samples into one-domain single crystals at room temperature. Complicated peak profiles prevent the determination of the exact symmetry and structure below the phase transition.
  2. Effect of delaying radiation on wound healing

    The effect of postwounding local radiation was measured in an animal model. Tensile strength and histologic appearance of wounds irradiated on Day 0, 3, and 5 were studied. The irradiated wounds were all significantly weaker than the nonirradiated wounds, but delaying the radiation did not benefit wound healing.
  3. Recent progress in BEDT-TTF based synthetic metals

    BEDT-TTF based organic metals with tetrahedral and linear anions are reviewed. New (ET){sub 2}MX{sub 4} complexes, their electrical and ESR properties are reported (M = Ga, In, Tl, and X is halides). A novel solid state phase transformation from semiconducting {alpha} to superconducting {beta}-(ET){sub 2}IBr{sub 2} is presented.
  4. Comparison of carbonate, citrate, and oxalate chemical routes to the high-T/sub c/ metal oxide superconductors La/sub 2-x/Sr/sub x/CuO/sub 4/

    In this communication the authors compare the carbonate, citrate, and oxalate solution techniques for the synthesis of the high-T/sub c/ compounds La/sub 2-x/Sr/sub x/CuO/sub 4/. The superconducting properties of the compounds are determined as much by the oxygen stoichiometry as by the metal stoichiometry, and therefore, the sintering and annealing temperatures and O/sub 2/ partial pressures all influence the conductive properties of the materials.
  5. Synthesis, structure and superconductivity of single crystals of high-T/sub c La/sub 1. 85/Sr/sub 0. 15/CuO/sub 4/

    Single crystals in the La-Ba-Cu-O system (LBCO) have been prepared, and x-ray structural characterization and superconducting properties of the crystals are reported. The superconductivity of the sample was detected by rf penetration depth measurements at 500 kHz. The onset temperature for the superconductivity (Tc) was 8.5 - 9.0 K with a broad transition and a low signal response. These findings indicate that only a small fraction of the sample had bulk superconductivity, and the crystals possess a range of Tc values. 13 references, 1 figure, 1 table.
  6. Recent progress in BEDT-TTF (bis(ethylenedithio)-tetratiofulvalene) based synthetic metals

    BEDT-TTF based organic metals with tetrahedral and linear anions are reviewed. New (ET)/sub 2/MX/sub 4/ complexes, their electrical and ESR properties are reported (M = Ga, In, Tl, and X is halides). A novel solid state phase transformation from semiconducting ..cap alpha.. to superconducting ..beta..-(ET)/sub 2/IBr/sub 2/ is presented. 40 refs., 5 figs., 2 tabs.
  7. Simpson's neutrino and the singular see-saw

    The authors of this paper derive explicit forms for the neutrino and lepton mixing-matrices which describe the generic singular see-saw model. The dependence on the hierarchy parameter is contrasted with the non-singular case. Application is made to Simpson's 17 keV neutrino.
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"Allen, T.J."

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