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Li3B5O8(OH)2 crystals were obtained in the system Li2O B2O3 H2O under hydrothermal conditions at fairly lower PT conditions. The crystals obtained were characterized through various techniques: XRD, wet chemical analysis and the measurement of ionic conductivity. 相似文献
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The whole plant of Phyllanthus wightianus (PW) was investigated for the antioxidant effects of three successive extracts: hexane (PWHE), chloroform (PWCE) and methanol (PWME), using standard in vitro models. The PWME exhibited a strong scavenging effect on 2,2-diphenyl-2-picryl hydrazyl (DPPH) free radicals and nitric oxide radical inhibition activity, due to possessing the highest content of tannins. The free radical scavenging effect of PWME was comparable with that of reference antioxidants. The extracts were subjected to isolation of their compounds: isomeric sterol mixture (1) [stigmasterol (1a), compesterol (1b) and β-sitosterol (1c)], fredilin (2), lupeol (3), gallic acid (4), bergenin (5), geraniin (6), corilagin (7) and ellagic acid (8) were established through the use of column chromatographic methods and spectral data. The percentage of tannins was also determined and estimated using the HPLC method. The data suggest that tannins are the active antioxidant compounds of P. wightianus. This study provides proof for the ethnomedical claims and reported biological activities of this plant. The plant therefore has very good therapeutic potential. 相似文献
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K. Namratha S. Suresha M. B. Nayan K. Byrappa 《Research on Chemical Intermediates》2011,37(2-5):531-539
Hydrothermal synthesis of silver-doped modified ZnO was carried out in the presence of a surface modifier. The experimental conditions were maintained constant (ZnO = 4 M; T = 250 °C; P = autogenous; Solvent = 1 N HCl; Duration = 24 h). Caprylic acid was used as a surface modifier with varying concentration from 0.1 to 2 mL. The experiments were carried out with Ag doping from 1 to 5 wt%. Hydrophobic silver-doped ZnO modified with caprylic acid was subjected to a systematic characterization using powder XRD, SEM, FTIR, and photocatalytic properties using Indigo Carmine dye. 相似文献
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K. Namratha K. Byrappa 《Progress in Crystal Growth and Characterization of Materials》2012,58(1):14-42
Novel solution routes covering a wide range of processes like hydrothermal, solvothermal and supercritical techniques have been described in detail with reference to the processing of a wide range of advanced inorganic nanocrystalline materials and organic-inorganic hybrid nanocrystalline materials. The significance of the thermochemical calculations, in situ surface modification and the experimental parameters has been discussed. One step in situ fabrication of advanced functional nanocrystalline materials by soft solution processing has also been discussed briefly. Synthesis of nanocrystals of metal oxides and hybrid nanocrystals and also processing several nanocomposites like carbon nanotubes: metal oxide, activated carbon: metal oxide, etc. has been reviewed in relation to various process parameters. The effect of doping, size, shape and quality on the properties of nanocrystalline materials has been discussed in relation to the photoluminescence and photocatalytic characteristics. 相似文献
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S. H. Patil S. I. Patil S. R. Patil S. M. Kadam B. K. Chougule K. Byrappa 《Czechoslovak Journal of Physics》1992,42(3):339-343
The variation of magnetization as a function of Zn concentration in the Mg-Zn system is measured using a high-field loop tracer at liquid nitrogen temperature. The XRD studies show that the lattice parameter increases linearly with increase in the zinc content. The magnetization is found to increase with the zinc concentration, reaches a maximum atx=0.2 and thereafter falls to zero for non magnetic zinc ferrite, which is the behaviour similar to other zinc containing ferrites. The variation of magnetization as a function of zinc content suggests the existence of a canted type of spin arrangement in this system. The cation distribution is suggested.The authers are thankful to Professor R. N. Patil for encouragement 相似文献
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