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61.
Kasarapu Venkataramana K. Ravindranath Chittimadula Madhuri Ch Madhusudan N. Pavan Kumar C. Vishnuvardhan Reddy 《Ionics》2018,24(5):1429-1438
Nanocrystalline co-doped ceria Ce0.8Sm0.2?xYxO2?δ solid electrolytes for intermediate-temperature solid oxide fuel cells (IT-SOFCs) were synthesized through sol–gel auto-combustion method. The prepared samples were sintered via microwave sintering at 1200 °C for 1 h. The X-ray diffraction analysis of co-doped ceria system reveals formation of the samples with a single-phase cubic fluorite structure. The lattice parameter values were calculated from X-ray diffraction patterns. The calculated crystallite sizes of all the samples were found to be in the range of 17 and 28 nm. Surface morphologies and elemental analysis of all the samples were carried out by using SEM and EDS analysis. The existence of chemical bonding in the samples was studied by FTIR spectroscopy. The presence of oxygen vacancies and evaluation of their concentration in the material was carried out using Raman spectroscopy analysis. Electrical properties of all the samples were analyzed by impedance spectroscopy. It was found that microwave sintered co-doped ceria sample Ce0.8Sm0.1Y0.1O2?δ exhibits the highest total ionic conductivity with minimum activation energy among all the compositions and conventional sintered sample. Therefore, it can be concluded that the microwave sintered Ce0.8Sm0.1Y0.1O2?δ sample may be useful as a promising electrolyte material for the IT-SOFCs. 相似文献
62.
Wang SQ Ravindranath S Boukany P Olechnowicz M Quirk RP Halasa A Mays J 《Physical review letters》2006,97(18):187801
Large step shear experiments revealed through particle tracking velocimetry that entangled polymeric liquids display either internal macroscopic movements upon shear cessation or rupturelike behavior during shear. Visible inhomogeneous motions were detected in five samples with the number of entanglements per chain ranging from 20 to 130 at amplitudes of step strain as low as 135%. 相似文献
63.
64.
Summary A method for the volumetric determination of tetraalkyl thiuram disulphide is developed. It is based on its reaction with potassium cyanide in aqueous acetonitrile medium, when the corresponding tetraalkyl thiuram monosulphide and thiocyanate are formed. The former is removed by extraction with benzene and the latter converted into cyanogen bromide, which is estimated iodometrically.
Zusammenfassung Ein Verfahren zur volumetrischen Bestimmung von Tetraalkyl-thiuramdisulfid wird beschrieben. Es beruht auf der Reaktion mit Kaliumcyanid in wäßriger Acetonitrillösung, wobei das entsprechende Tetraalkyl-thiurammonosulfid und Thiocyanat gebildet werden. Ersteres wird durch Extraktion mit Benzol entfernt; das Thiocyanat wird in Bromcyan umgewandelt, das dann jodometrisch bestimmt wird.相似文献
65.
Françoise Van Gastel Lisa Agocs Andrew A. Cherkas John F. Corrigan Simon Doherty Ravindranath Ramachandran Nicholas J. Taylor Arthur J. Carty 《Journal of Cluster Science》1991,2(2):131-136
Thecloso octahedral cluster Ru4(CO)11(μ4-PPh)(μ4-S)1 and selenium and tellurium analogues, the first examples of unsaturated ruthenium clusters with a planar metal core and different main group 15 and 16 atoms have been synthesized fromnido Ru4(CO)13(μ3-PPh). An X-ray analysis of1 and Ru4(CO)10(μ4-PPh)(μ4-Se)(PEt3)2a has confirmed thetrans disposition of phosphorus and group 16 main group fragments. 相似文献
66.
N. Krishnamurthy B. Ravindranath T.N.Guru Row K. Venkatesan 《Tetrahedron letters》1982,23(21):2233-2236
The controversy with regard to the structures of the closely related polyisoprenylated phenolic compounds, garcinol, isogarcinol, camboginol, cambogin, xanthochymol and isoxanthochymol is cleared by X-ray crystallographic analysis of the naturally occurring isogarcinol. The unusual UV spectral characteristics of the chromophore of isogarcinol are discussed. 相似文献
67.
Chemical examination of the aerial parts of Cleistanthus collinus afforded the arylanphthalide lignans, cleistanone (1), diphyllin (2), cleistanthins A (3), C (4) and D (5), and 4-O-(3"-O-methyl-beta-D-glucopyranosyl)-diphyllin (6). The first compound is a new member of the rare group of arylnaphthalide lignans containing an alkoxy group on the lactone ring. The structure of the compound was determined from its spectral data, chemical transformations and partial synthesis from diphyllin (2). The new lignan, 1 and its acetyl derivative, 7 were found to exhibit cytotoxicity against MT(2) cell lines. 相似文献
68.
Krishnarao Sandhya 《Tetrahedron letters》2008,49(15):2435-2437
Fmoc-amino acids are conveniently and inexpensively linked to Wang resin using benzyloxybenzyl chloride resin without the problems normally associated with the traditional methods of preparation of Fmoc-amino acid loaded Wang resins, namely, low substitution, unacceptable racemization or use of expensive reagents. 相似文献
69.
Ravindranath Singh Rathore 《Crystal Research and Technology》2005,40(6):627-632
Crystal structure of a terminally blocked synthetic peptide, t‐Boc‐L‐Val‐Aib‐Gly‐L‐Leu‐OMe has been investigated. Two different conformers of peptide with one co‐crystallized water molecule, coexist in the crystal structure, in C2 space group. Both the conformers are stabilized by two intramolecular 1← 4 hydrogen bonds, between (Boc) C=O … HN (Gly) and (Val) C=O … HN (Leu), forming consecutive type II‐I' β‐turns. In the crystal, water interlinks peptide molecules, making a triangular bridge of pyramidal type. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
70.
T. Narasimhamurthy J. C. N. Benny K. Pandiarajan Ravindranath S. Rathore 《Acta Crystallographica. Section C, Structural Chemistry》2003,59(11):o620-o621
The structure of the title compound, C17H16OS, is primarily stabilized by T‐shaped and parallel‐displaced aromatic clusters. The distances between the centroids of the aromatic pairs are in the range 4.34–5.30 Å. In the crystal packing, the molecules dimerize by means of π–π interactions of both face‐to‐face and edge‐to‐face types, and the aromatic rings associate in a cyclic edge‐to‐face tetrameric arrangement of the herring‐bone type. These herring‐bone interactions appear to insulate hydrogen‐bond interactions in the crystal structure. 相似文献