- Preparation of Bi-based high-Tc superconducting films from methacrylate solutions
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Bi2Sr2CaCu2Ox superconducting films containing minor amounts of Bi2Sr2Ca2Cu3Ox were prepared by spray pyrolysis of methacrylate solutions on LaAlO3 substrates. The best superconducting properties (Tc ? 80 K, ΔTc ? 10 K) were shown by the films annealed at 850°C, which consisted mainly of platelike crystallites with a high degree of [001] orientation. The composition, content, and morphology of the calcium strontium cuprates and oxides present as impurity phases were found to correlate with the annealing temperature and film thickness.
- Men'shikh,Geras'kina,Prutchenko,Rybakova,Tomashpol'skii
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p. 517 - 520
(2008/10/08)
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- Preparation of 2,5-dimethyl-4-hydroxy-2,3-dihydrofuran-3-one
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A process for the preparation of the sought-after scent 2,5-dimethyl-4-hydroxy-2,3-dihydrofuran-3-one, and novel intermediates for the preparation of this compound. 2,5-Dimethyl-4-hydroxy-2,3-dihydrofuran-3-one is prepared by first epoxidizing hex-3-ene-2,5-diol in the liquid phase with hydrogen peroxide to give the novel compound 3,4-epoxy-hexane-2,5-diol, which at 40°-280° C. is converted, by means of a catalytic amount of an acid, to the novel compound 2,5-dimethyl-3,4-dihydroxy-tetrahydro-furan. The latter is dehydrogenated by means of oxygen over a silver catalyst or copper catalyst to give the nove compound 2,5-dimethyl-4-hydroxy-tetrahydrofuran-3-one, which is oxidized by means of bismuth oxide, in concentrated acetic acid solution, to give the desired compound 2,5-dimethyl-4-hydroxy-2,3-dihydrofuran-3-one.
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