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1.
Tokeer Ahmad Kandalam V. Ramanujachary Samuel E. Lofland Ashok K. Ganguli 《Journal of Chemical Sciences》2006,118(6):513-518
Nanoparticles of complex manganites (viz. LaMnO3, La0.67Sr0.33MnO3 and La0.67Ca{0.33}MnO3) have been synthesized using the reverse micellar route. These manganites are prepared at 800‡C and the monophasic nature
of all the oxides has been established by powder X-ray diffraction studies. TEM studies show an average grain size of 68,
80 and 50 nm for LaMnO3, La0.67Sr0.33MnO3 and La0.67Ca{0.33}MnO3respectively. Ferromagnetic ordering is observed at around 250 K for LaMnO3, 350 K for La0.67Sr0.33MnO3 and 200 K for La0.67Ca{0.33}MnO3. These Curie temperatures correspond well with those reported for bulk materials with similar composition. 相似文献
2.
Sankar Prasad Bhuniya Safikur Rahman Anshul J. Satyanand Mahendrasinh M. Gharia Ashok M. Dave 《Journal of polymer science. Part A, Polymer chemistry》2003,41(11):1650-1658
Maize starch was modified by allyl chloride adopting an interfacial reaction technique with cetyltrimethyl ammonium bromide as a phase‐transfer catalyst and pyridine as an acid acceptor. The degree of substitution was determined from an increasing carbon content of the modified starch. The percentage of carbon and hydrogen of the allyl‐modified starch was estimated by elemental analysis (C, H, and N), and the product characterization was done through 1H NMR and 13C NMR analyses. The allyl‐modified starch was then copolymerized with methacrylic acid and a combination of methacrylic acid and acrylamide at 50 and 70 °C with potassium persulfate as an initiator. The copolymer thus formed swelled in distilled water after neutralization with sodium carbonate. The percentage of absorption capacity of the hydrogels was determined with distilled water and 0.9% NaCl solution. The highest percentage of absorption, 6500%, was achieved for the developed hydrogel containing allyl starch and acrylic monomer in a 1.7:1 w/w ratio and acrylic monomer, namely, methacrylic acid and acrylamide in a 3.2:1 w/w ratio. The study on biodegradability of the developed hydrogel showed that the hydrogel is degradable in the presence of diastase (amylase). © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 1650–1658, 2003 相似文献
3.
An efficient synthesis of [1,3]oxazino[2,3-a]quinoline derivatives via a three-component reaction of quinoline, DMAD and carbonyl compounds is described. 相似文献
4.
Anshu Dandia Ruby Singh Dharmendra Singh Ashok Laxkar Asha Sivpuri 《Phosphorus, sulfur, and silicon and the related elements》2013,188(12):2472-2479
A dry media procedure has been developed for the synthesis of a series of new class of pyrazolo [4,3-c][1,5]benzothiazepines 6 under microwave irradiation using montmorillonite K10 as solid support. The catalyst can be recovered and reused. Thus, the procedure provides a simple and green synthetic methodology under environmentally friendly conditions. Antifungal screening of synthesized compounds has shown promising activity. Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file. 相似文献
5.
Thermal expansion measurements have been carried out on Fe substituted superconducting compounds Y1Ba2(Cu1−x
Fe
x
)3O
y
(0<x<4%) using a high resolution dilatometer employing the three terminal capacitance technique. The experimental set up is sensitive
enough to detect changes in α of less than 10−8K−1. Results show that the jump Δα in the coefficient of linear thermal expansion at the superconducting transition temperature,T
c, increases almost linearly with Fe concentration. The normal state thermal expansion coefficient α first decreases, attains
a minimum value aroundx=1% and then increases for higher Fe concentrations. The oxygen content per unit formula is almost constant up tox=1% and then increases rapidly withx. It has also been observed that the anomalous behaviour of α around 260 K observed by Meingastet al [22] for Fe concentrationx=5% is due to inadequate annealing of the sample. 相似文献
6.
S K Deshpande S M Chaudhari Ashok Pimpale A S Nigavekar S B Ogale V G Bhide 《Pramana》1991,37(4):373-385
An automated linear laboratory EXAFS spectrometer of the Johansson type has been indigenously developed. Only two translational
motions are required to achieve the necessary Rowland circle configuration for the (fixed) X-ray source, the dispersing and
focusing bent crystal and the receiving slit. With the available crystals the spectral region from 5 to 25 keV can be scanned.
The linear motions of the crystal and receiving slit including the detector assembly are achieved by employing software-controlled
DC motors and utilizing optical encoders for position sensing. The appropriate rotation of the crystal is achieved by the
geometry of the instrument. There is a facility to place the sample alternately in the path of the X-ray beam and out of the
path to record both the incident X-ray intensityI
0 and the transmitted intensityI employing the scintillation detector. An arrangement with a two-window proportional detector before the sample to measureI
0 and the scintillation detector to recordI is also developed; in this case it is not necessary to oscillate the sample. Fast electronic circuits are employed to minimize
counting errors. The instrument is user-friendly and it is operated through a menu-driven IBM compatible PC. EXAFS spectra
of high resolution have been recorded using the spectrometer and employing the Si(111) reflecting planes; the X-ray source
being a Rigaku 12 kW rotating anode with Cu target. We describe the spectrometer and discuss its performance with a few representative
spectra. 相似文献
7.
The high spin yrast states uptoJ=22+ in182,184,186Os are studied in a microscopic variational approach with number-conserved projected states. The energy spectra, quadrupole,
moments andB (E2) values are calculated by employing the Hamiltonian with quadrupole plus pairing interactions. The results of the calculations
are in fair agreement with the available experimental data. 相似文献
8.
The high spin yrast states up toJ=20+ in184, 186Pt and190, 192, 194Pt are studied in a microscopic approach of variation with number-conserved projected states. The energy spectra, quadrupole
moments andB(E2) values are calculated by employing the Hamiltonian with quadrupole plus pairing interactions. The results of the calculations
are in fair agreement with the available experimental data. 相似文献
9.
10.
A four-noded rectangular element with seven degrees of freedom at each node is developed for buckling analysis of laminated plate structures having any number of layers with a constant thickness of individual layers. The displacement model is so chosen that it can explain adequately the parabolic distribution of transverse shear stresses and the non-linearity of in-plane displacements across the thickness. A geometrical stiffness matrix is developed using in-plane stresses. A wide range of plates from thick to thin are examined under uniaxial loading conditions. The results are compared with the existing analytical and numerical solutions. The present formulations confirm its applicability for buckling analysis of a wide range of plates. 相似文献