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991.
992.
A. Chandra Shekhar A. Ravi Kumar G. Sathaiah K. Raju P. V. S. S. Srinivas P. Shanthan Rao B. Narsaiah 《Journal of heterocyclic chemistry》2014,51(5):1504-1508
A versatile synthetic route for the preparation of 2,3,6‐trisubstituted quinoxalines in excellent yield is developed from θ‐diamines and 1,2‐dicarbonyl compounds in which aqueous hydrofluoric acid was employed as the medium and catalyst. Other salient features of this protocol include milder conditions, absence of coupling agents, and easy workup procedures. 相似文献
993.
S. J. Sartandel S. Chinnaesakki S. V. Bara N. S. Krishna A. Vinod Kumar R. M. Tripathi 《Journal of Radioanalytical and Nuclear Chemistry》2014,299(1):337-342
Environmental gamma radiation levels around the new Bhabha Atomic Research Centre site at Visakhapatnam have been assessed. Natural and anthropogenic radionuclide activity concentrations in soil samples collected were determined using high-resolution gamma spectroscopy. Average activity concentrations of 238U, 226Ra, 232Th and 40K were found to be 38, 38, 230 and 520 Bq kg?1, respectively. No anthropogenic radionuclide except fallout 137Cs having mean concentration range ≤ 0.2–2.2 Bq kg?1 was detected in the soil samples. The observed values are compared with the values reported for different areas in India and other parts of the world. The annual total external gamma radiation dose to the members of public estimated using the above observations ranged from 0.13 to 0.38 mSv y?1 with an average of 0.25 mSv y?1. 相似文献
994.
995.
Venkata Giridhar Poosarla T. S. Chandra 《Applied biochemistry and biotechnology》2014,173(6):1375-1390
An aerobic xylanolytic moderately halophilic and alkali-tolerant bacterium, Gracilibacillus sp. TSCPVG, produces multiple xylanases of unusual halo-acid-alkali-thermo-stable nature. The purification of a major xylanase from TSCPVG culture supernatant was achieved by hydrophobic and gel permeation chromatographic methods followed by electroelution from preparatory PAGE. The molecular mass of the purified xylanase was 42 kDa, as analyzed by SDS-PAGE, with a pI value of 6.1. It exhibited maximal activity in 3.5 % NaCl and retained over 75 % of its activity across the broad salinity range of 0–30 % NaCl, indicating a high halo-tolerance. It showed maximal activity at pH 7.5 and had retained 63 % of its activity at pH 5.0 and 73 % at pH 10.5, signifying the tolerance to broad acid to alkaline conditions. With birchwood xylan as a substrate, K m and specific activity values were 21 mg/ml and 1,667 U/mg, respectively. It is an endoxylanase that degrades xylan to xylose and xylobiose and had no activity on p-nitrophenyl-β-d-xylopyranoside, p-nitrophenyl-β-d-glucopyranoside, p-nitrophenyl acetate, carboxymethylcellulose, and filter paper. Since it showed remarkable stability over different salinities, broad pH, and temperature ranges, it is promising for application in many industries. 相似文献
996.
997.
Y. Chandra R. Chowdhury S. Adhikari F. Scarpa 《Physica E: Low-dimensional Systems and Nanostructures》2011,44(1):12-16
In-plane elastic instability of bilayer graphene sheets is investigated using atomistic finite element approaches. The equivalent homogenised properties of graphene sheet are expressed in terms of the thickness, equilibrium lengths and force-field models used to represent the C–C bonds of the graphene lattice. The covalent bonds are represented as structural beams with stretching, bending, torsional and shear deformation, and the strain energies associated to affine deformation mechanisms. The overall mechanical properties and geometric configurations of the nano-structures represented as truss assemblies are then calculated minimising the total potential energy associated to the loading, thickness and average equilibrium lengths of the bonds. Different boundary conditions and aspect ratios are considered for both bilayer and single-layer graphene sheets. The bilayer graphene sheets are found to be offering remarkably higher buckling strengths as compared to single-layer sheets. 相似文献
998.
An access to different glycohybrids involving nucleophilic addition of N- and C-nucleophiles to the butenonyl glycosides followed by cyclization and subsequent reactions is reported. In the present communication, three different prototypes, β-D-glucopyranosylmethyl pyrazolines, β-D-glucopyranosylmethyl pyrimidines and β-D-glucopyranosylmethyl biphenyls, were prepared in moderate to good yields. 相似文献
999.
S. Parida N. Chandra R. Ghosh 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2011,65(3):303-329
The simultaneous emission of two electrons in photoionization, or in the non-radiative
spontaneous decay of an inner-shell vacancy, are two of the best known examples of the
failure of the independent-particle model of atoms and molecules. The later of these
provides also one of the two competitive processes, following inner-shell photoionization,
for producing three flying electrons which can, for example, be used in implementing many
protocols hitherto developed in quantum information. The correlation properties of the
three-particle system consisting of these two electrons plus the photoelectron are
analyzed using methods from quantum information theory. The entanglement of the consequent
tripartite spin-state is shown to be completely independent of the mechanism(s) which may
be responsible for the emission of these three electronic qubits in two different steps in
the absence of spin-orbit interaction. Our analysis shows that the tripartite state formed
in the present case is more like a |W〉 class of states possessing pairwise
entanglement. The experimental characterization of these states is fully achieved merely
by the measurements of the energies of three flying electrons, without requiring any
entanglement witness or other similar protocols hitherto developed in quantum information.
Changes in these entanglement properties of a tripartite state of electronic qubits on the
inclusion of the spin-orbit interaction have also been discussed. 相似文献
1000.