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41.
42.
A canonical planar beta-hairpin peptide, stereochemically reengineered into a semicircular bracelet type motif by L-to-D stereochemical inversion in two pairs of its cross-strand neighbor residues, displays protein like ordering including two-state behavior in H2O, which is unusual for a small peptide of this size. 相似文献
43.
S. Kundu 《Ukrainian Mathematical Journal》2013,65(6):945-952
44.
This is a study of the completeness properties of the space C
ps
(X) of continuous real-valued functions on a Tychonoff space X, where the function space has the pseudocompact-open topology. The properties range from complete metrizability to the Baire
space property.
Dedicated to Professor Robert A. McCoy 相似文献
45.
The effect of lattice anharmonicity on the resonant modes of dilute impurities for Au-Cu, Au-Ag and W-Cr metallic systems
are studied from the poles of the double time temperature dependent impure Green’s function of these crystals. The third order
force constants used in the present work are derived assuming the systems to obey the Lennard-Jones potential. The inclusion
of lattice anharmonicity has been found to increase the resonant frequency which depends upon the mass defect, force constant
change parameter and the impurity concentration terms. Some interesting features about the phase shift and the change in width
of the vibrational spectrum are reported at room temperature for the isotopic defects and the defects interacting with host
atoms. The results are found to be in qualitative agreement with the experiments on the systems considered. 相似文献
46.
A simple theoretical analysis is presented for Mössbauer parameters and frequency moments of dilute57Fe impurities in different metallic hosts. These parameters have been evaluated for a general harmonic solid using Green's function method. Our results suggest that the contribution due to force constant change term is significant for the mean square displacement whereas that due to mass disordering term is predominating in the evaluations of mean square velocity. The variation of frequency moments for the impurity with host Debye-temperatures modified by the host to impurity mass ratios are shown for a number of solids. 相似文献
47.
Effect of polarization on two-dimensional carrier distribution in nitride quantum wells 总被引:1,自引:0,他引:1
Bidisha Lahiri Reshmee Datta Sudakshina Kundu 《Physica E: Low-dimensional Systems and Nanostructures》2005,25(4):449-455
Wide band-gap group-III nitrides are important for the design of optical devices in the blue and blue–green region. Owing to their wurtzite structure, these materials have a strong inherent polarization field that affects carrier distribution, exciton stability and hence influences the optical properties of the devices. So far, carriers have been assumed to have a sheet-like character. In this paper a non sheet-like distribution function for these quasi two-dimensional carriers is proposed that incorporates the effect of the polarization field. Here GaN/InGaN/GaN and AlGaN/GaN/AlGaN quantum wells have been studied. The polarization field causes the electron and hole wave functions to separate out, thus causing decrease of emission strength and strong reduction of exciton binding energy. This treatment explains well the qualitative nature of carrier distribution in the well. The polarization field changes with GaN mole fraction present in the tertiary nitride layer. The effect of mole fraction on carrier distribution has also been studied. It is found that, inside the well, the hole distribution changes a little more with change in mole fraction than the electron distribution, but for all practical purposes the net change in the distribution pattern is negligible. 相似文献
48.
Pradipta Sinha Moloy Banerjee Abhijit Kundu Sujit Roy 《Journal of Chemical Sciences》2002,114(4):277-283
The reaction of allyl halide and a carbonyl compound under the aegis of tetragonal tin(II) oxide and catalyticd
8,d10 metal complexes provides the corresponding homoallylic alcohol, via a novel allyl tin intermediate. 相似文献
49.
50.
Banerjee M Maiti S Kundu I Chakrabarti A Basu S 《Photochemistry and photobiology》2010,86(6):1237-1246
The carcinogenic drug 4-nitroquinoline-1-oxide (4NQO) has been found to bind with the protein hen egg white lysozyme as evident from fluorescence quenching experiments. The binding constant and stoichiometry have been determined. The values of the thermodynamic parameters indicate that the interaction is an enthalpy-driven spontaneous phenomenon. The experimental value of change in free energy is similar to that obtained from the docking study. The far UV circular dichroism spectra show some changes in the secondary structure of protein. The high value of bimolecular quenching constant leads to the possibility of Förster resonance energy transfer (FRET). Along with FRET, the photoinduced electron transfer (PET) from tryptophan residue of protein to 4NQO has also been evident from the transient absorption spectra obtained in laser flash photolysis experiments. The simultaneous occurrence of FRET and PET is the key factor for quenching of intrinsic fluorescence of the protein as it binds with the drug. 相似文献