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71.
Chowdhury Ipsita Hazra Ghosh Sourav Roy Mouni Naskar Milan Kanti 《Journal of Sol-Gel Science and Technology》2015,74(1):199-207
Journal of Sol-Gel Science and Technology - Silver nanoparticles (AgNPs) dispersible in water were synthesized at room temperature in the presence of carambola fruit extract at different pH. The... 相似文献
72.
73.
Damped transient dynamic elasto-plastic analysis of plate is investigated. A finite element model based on a C
0 higher order shear deformation theory has been developed. Nine noded Lagrangian elements with five degrees of freedom per
node are used. Selective Gauss integration is used to evaluate energy terms so as to avoid shear locking and spurious mechanisms.
Von Mises and Tresca yield criteria are incorporated along with associated flow rules. Explicit central difference time stepping
scheme is employed to integrate temporal equations. The mass matrix is diagonalized by using the efficient proportional mass
lumping scheme. A program is developed for damped transient dynamic finite element analysis of elasto-plastic plate. Several
numerical examples are studied to unfold different facets of damping of elasto-plastic plates. 相似文献
74.
Suraj P. Narula Sajeev Soni Meenu Puri Rishi D. Anand Jugal K. Puri 《Phosphorus, sulfur, and silicon and the related elements》2013,188(7):1647-1654
Si(NHC6H5-nFn)4.xTiCl4 [n = 2–5; x = 3,4] are obtained from the disproportionation reactions between (CF3CH2O)3SiNHC6H5-nFn (n = 2–5) and TiCl4 in petroleum ether (40–60°C) at 0°–10°C. These complexes are characterized by elemental analyses and IR, 1H, and 19F NMR spectroscopy. Unlike the reported5 complex Si(NHC6H4F-o)4.3TiCl4, these are non-ionic in nature. All complexes give double adducts with CH3NO2 and CH3CN within 24 h. 相似文献
75.
Krishnendu B. Sahu Arindam Maity Shyamal Mondal Rupankar Paira Pritam Saha Subhendu Naskar Abhijit Hazra Sukdeb Banerjee Nirup B. Mondal 《Journal of heterocyclic chemistry》2013,50(Z1):E148-E155
A basic alumina‐supported microwave assisted simple methodology has been developed for the synthesis of aryl‐heteroaryl methanes (benzylated quinolones) via transition metal catalyzed cross‐coupling reaction of halo substituted polynuclear oxa‐aza quinolones with benzyl indium, an organometallic reagent easily derived from commercially available benzyl bromide. 相似文献
76.
Dinabandhu Naskar Subhasish Neogi Amrita Roy Ashis Baran Mandal 《Tetrahedron letters》2008,49(48):6762-6764
Indoles can serve as substrates for the Petasis boronic acid-Mannich reaction, providing a practical synthetic route for C-C bond formation in α-(N-substituted indole)carboxylic acids. The scope and limitations of this method have been examined. 相似文献
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79.
A novel flavanonol (1), three new isoflavones (2-4) and a new flavan-3-ol (5) were isolated along with ten other known flavonoids (6-15) from the methanolic extract of propolis collected from Chitwan, Nepal. Their structures were determined on the basis of spectral analysis. 相似文献
80.
Dhungana S Harrington JM Gebhardt P Möllmann U Crumbliss AL 《Inorganic chemistry》2007,46(20):8362-8371
A complete characterization of the aqueous solution Fe(III) and Fe(II) coordination chemistry of a saccharide-based ferrichrome analogue, 1-O-methyl-2,3,6-tris-O-[4-(N-hydroxy-N-ethylcarbamoyl)-n-butyryl]-alpha-D-glucopyranoside (H3LN236), is reported including relevant thermodynamic parameters and growth promotion activity with respect to both Gram-negative and Gram-positive bacterial strains. The saccharide platform is an attractive backbone for the design and synthesis of ferrichrome analogues because of its improved water solubility and hydrogen-bonding capabilities, which can potentially provide favorable receptor recognition and biological activity. The ligand deprotonation constants (pKa values), iron complex (FeIII(LN236) and FeII(LN236)1-) protonation constants (KFeHxL-236-N), overall Fe(III) and Fe(II) chelation constants (beta110), and aqueous solution speciation were determined by spectrophotometric and potentiometric titrations, EDTA competition equilibria, and cyclic voltammetry. Log betaIII110 = 31.16 and pFe = 26.1 for FeIII(LN236) suggests a high affinity for Fe(III), which is comparable to or greater than ferrichrome and other ferrichrome analogues. The E1/2 for the FeIII(LN236)/FeII(LN236)1- couple was determined to be -454 mV (vs NHE) from quasi-reversible cyclic voltammograms at pH 9. Below pH 6.5, the E1/2 shifts to more positive values and the pH-dependent E1/2 profile was used to determine the FeII(LN236)1- protonation constants and overall stability constant log betaII110 = 11.1. A comparative analysis of similar data for an Fe(III) complex of a structural isomer of this exocyclic saccharide chelator (H3LR234), including strain energy calculations, allows us to analyze the relative effects of the pendant arm position and hydroxamate moiety orientation (normal vs retro) on overall complex stability. A correlation between siderophore activity and iron coordination chemistry of these saccharide-hydroxamate chelators is made. 相似文献