5,019 research outputs found

    Chemical effects of photonuclear reactions in the propyl bromides

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    When nuclear reactions occur in atoms in molecules chemical changes follow as a result of the recoil of the product atoms. The nature of these chemical changes has been studied intensively for a number of systems but in most cases the magnitude of the recoil energy has been about the same. In the present studies use was made of a much greater recoil energy than that normally used. The reaction Br(γ,η)Br* gives a recoil bromine2 atom with an energy of the order 105ev, compared to 102ev for the product of the Br(η,γ)Br* reaction which is usually used

    The effect of oxygen on the recoil reactions of carbon-11 in hydrocarbons

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    The recoil reactions of carbon-11 produced by the c 12 (y, n)C11 reaction in benzene, cyclohexane, and n-hexane have been studied. Using gas chromatography for the analysis, the yields of carbon-11 labeled methane, ethane, ethylene, and acetylene were determined. The effect of radiation dose and oxygen scavenger on these yields was investigated

    Growth and characterization of multiferroic BiMnO3_3 thin films

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    We have grown epitaxial thin films of multiferroic BiMnO3_3 using pulsed laser deposition. The films were grown on SrTiO3_3 (001) substrates by ablating a Bi-rich target. Using x-ray diffraction we confirmed that the films were epitaxial and the stoichiometry of the films was confirmed using Auger electron spectroscopy. The films have a ferromagnetic Curie temperature (TCT_C) of 85±\pm5 K and a saturation magnetization of 1 μB\mu_B/Mn. The electric polarization as a function of electric field (P−EP-E) was measured using an interdigital capacitance geometry. The P−EP-E plot shows a clear hysteresis that confirms the multiferroic nature of the thin films.Comment: 4 pages, 4 figures, submitted to J. Appl. Phy

    Surface resonance of the (2×1) reconstructed lanthanum hexaboride (001)-cleavage plane : a combined STM and DFT study

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    We performed a combined study of the (001)-cleavage plane of lanthanum hexaboride (LaB6) using scanning tunneling microscopy and density-functional theory (DFT). Experimentally, we found a (2×1) reconstructed surface on a local scale. The reconstruction is only short-range ordered and tends to order perpendicularly to step edges. At larger distances from surface steps, the reconstruction evolves to a labyrinthlike pattern. These findings are supported by low-energy electron diffraction experiments. Slab calculations within the framework of DFT show that the atomic structure consists of parallel lanthanum chains on top of boron octahedra. Scanning tunneling spectroscopy shows a prominent spectral feature at −0.6eV. Using DFT, we identify this structure as a surface resonance of the (2×1) reconstructed LaB6 (100) surface which is dominated by boron dangling bond states and lanthanum d states

    Some Materials And Methods For Teaching Forestry In North Carolina High Schools

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    This study was proposed (1) to teach high school students a basic course in forestry (2) to carry out an extensive study of units dealing with different methods, techniques and materials for teaching forestry and (3) to make recommendations concerning some methods and materials that are adaptable to teaching forestry in secondary schools of North Carolina

    Photoproduction of calcium-47*

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    The irradiation of highly enriched Ca 48co3 with a bremsstrahlung beam of maximum energy 46 Mev produced Ca47 with a yield of 1. 1 to 3 . O uc/mg Ca48 at half-saturation. The half-life of a sample measured through aluminum absorber to eliminate the contribution by the sc47 daughter was 4. 51 ±. 0 . 02 days . By comparison with the Cu63( 7, n)Cu62 reaction the integrated cross section from 0 to 46 Mev for the sum of the reactions ca48( 7, n)Ca47 and Ca48( 7\u27, p)K47 was calculated to be 29 Mev-mbarn. The Ca46 content of the sample calculated to the end of the bombardment was,.. 0. 040/o, probably the result of the Ca 48 ( ?\u27, 3n) and ( 7, p2n) reactions
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