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101.
Lead scandium phosphate glasses (PbO-Sc2O3-P2O5) containing different concentrations of tungsten oxide (WO3) ranging from 0 to 5 mol% were prepared. A number of studies, viz. differential thermal analysis (DTA), infrared spectra, optical absorption, and electron spin resonance (ESR) spectra, have been carried out. The results of DTA indicated the highest glass forming ability for the glass containing 5 mol% of WO3. The results of spectroscopic studies have been analyzed in light of different oxidation states of tungsten ions. 相似文献
102.
Arvind Samariya S.N. Dolia Arun S. Prasad P.K. Sharma S.P. Pareek M.S. Dhawan Sudhish Kumar 《Current Applied Physics》2013,13(5):830-835
CaFe2O4 nanocrystalline powders were synthesized through sol–gel treatment in which the stoichiometric mixing of various nitrates involving calcium and iron in presence of citric acid was performed. Subsequently, the as prepared sample was annealed at various temperatures in order to obtain the fine distribution of size including the bulk counterpart. The samples were then characterized using powder X-ray diffraction followed by 57Fe Mössbauer spectroscopy, SQUID as well as vibrating sample magnetometry. The results of spectroanalyses revealed that the samples were formed in single phase cubic spinel structure and exhibits room temperature superparamagnetism, except the bulk one, which crystallizes in characteristic orthorhombic structure of CaFe2O4 and displays trivial coercivity and remanent magnetization at room temperature. 相似文献
103.
M. A. Sridhar N. K. Lokanath J. Shashidhara Prasad C. V. Yelammagad S. K. Varshney 《Liquid crystals》2013,40(1):45-49
The title compound, cholesteryl 6[4-(4-pentyloxyphenylethynyl)phenoxy]hexanoate (DMT5), a cholesterol-based dimesogen, crystallizes in the monoclinic space group P21 with the parameters a = 9.812(3) Å, b = 9.713(2) Å, c = 24.179(2) Å, β = 92.48(1)° V = 2302.2(9) Å3, Z = 2, F000 = 836, λ(MoKα) = 0.71069 Å, μ = 0.067 cm 1, final R = 0.0772. The structure has intermolecular hydrogen bonds; it is stabilized by the presence of intermolecular contacts whose spacings are less than van der Waals' radii. 相似文献
104.
105.
106.
E-2-Penten-4-yn-1-ol (3) has been utilized as a source for 1,3-diene systems by employing lithium amide induced alkylation, and curpous iodide catalysed Grignard coupling reaction as key steps. Its application for the synthesis of (Z,E)-9,11-tetradecadienyl acetate and (E,E)-10,12-hexadecadienal is described. 相似文献
107.
Organic halides absorbed without solvent onto sodium phenylsulfinate on alumina (1) gave phenylsulfones (2) under microwave or ultrasound activation. 相似文献
108.
109.
Synthesis and characterization of supramolecular optically active bisamides derived from amino acids
The synthesis and phase transitional behaviour of three pairs of enantiomeric supramolecular hexacatenar liquid crystals (LCs) derived from natural α-amino acids such as l/d-alanine, l/d-leucine and l/d-valine are described. Their preparation with high enantiomeric purity was accomplished by condensing optically active (amino acid residue containing) trialkoxy amines with a 3,4,5-trialkoxy cinnamic acid core using a peptide coupling reagent namely, 2-(1H-benzotriazol-1-yl)-1,1,3,3-tetramethyl-uronium hexafluorophosphate (HBTU). The mesomorphic behaviour of these self-complementing mesogens was ascertained by polarising optical microscopy, differential scanning calorimetry and X-ray diffraction. The compounds exhibit columnar (Col) phase over a wide thermal range. Particularly, a pair of enantiomers derived from l/d-leucine residues notably stabilize hexagonal Col (Colh) phase over a wide temperature range of ?5 °C to 180 °C. Circular dichroism (CD) and FTIR studies suggest the chiral (helical) organization of mesogens within the columns through intermolecular hydrogen bonding; thus, these enantiomers represent one of the rarely reported examples of LCs exhibiting supramolecular Colh phase at room temperature. The gelation studies reveal the ability of these bisamides to form stable supramolecular gels in ethanol caused through H-bonding interactions. 相似文献
110.