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Mitra A.K.,Government General Degree College | Sau A.,Saha Institute of Nuclear Physics | Bera S.C.,Saha Institute of Nuclear Physics | Basu S.,Saha Institute of Nuclear Physics
Journal of Fluorescence

We present here a detailed photophysical study of a recently synthesised fluorophore 8-methyl-8,9-dihydro-5H-[1,3]dioxolo[4,5-b]carbazol-6(7H)-one. This is a synthetic precursor of bio-active carbazole skeleton Clausenalene. Spectroscopic investigation of the fluorophore has been carried out in different protic and aprotic solvents, as well as in binary solvent mixtures, using absorption, steady-state and time-resolved fluorescence techniques. This fluorophore is particularly responsive to the hydrogen bonding nature as well as polarity of the solvent molecules. When considered in micelles and β-cyclodextrin, this behaves as a reporter of its immediate microenvironment. Steady state and time resolved fluorometric and circular dichroism techniques have been used to explore the binding interaction of the fluorophore with transport proteins, bovine serum albumin and human serum albumin. The probable binding sites of the fluorophore in the proteinous environments have been evaluated from fluorescence resonance energy transfer study. Laser flash photolysis experiments also have been performed to observe the triplet excited state interaction between the fluorophore and albumin proteins. © 2015 Springer Science+Business Media New York. Source

Anirban S.,University of Burdwan | Anirban S.,Government General Degree College | Paul T.,University of Burdwan | Dutta A.,University of Burdwan
RSC Advances

The oxygen vacancy evolution and ion dynamics in Dy doped nanoceria have been investigated with microstructural, optical and ionic conductivity studies. The influence of Dy3+ ions on the microstructures and the optical and ionic conductivity properties of these nanoparticles has been studied using X-ray diffraction, HR-TEM, EDAX, UV-vis, Raman and impedance spectroscopy. From Rietveld refinement of the XRD profiles, it has been found that the oxygen vacancies, lattice parameters and Ce-O bond lengths increase with Dy3+ ion concentration. The Rietveld analysis, together with HR-TEM, confirms the cubic fluorite structure with space group Fm3m of all the samples. The EDAX spectra show good stoichiometry of the different atoms in the samples. The direct band gap, calculated from UV-vis spectra, shows a red shift with increasing concentration of Dy3+ ions. Raman spectroscopy studies of the samples gave insight into their vibrational properties and pointed to the fact that the oxygen vacancy content increased significantly with the doping concentration. The number of oxygen vacancies and their interaction with dopant cations strongly influence the electrical properties of Dy doped ceria. This journal is © The Royal Society of Chemistry. Source

Das K.,Abnseal College | Acharya N.,Government General Degree College | Kundu P.K.,Jadavpur University
Alexandria Engineering Journal

The present paper investigates numerically the influence of melting heat transfer and thermal radiation on MHD stagnation point flow of an electrically conducting non-Newtonian fluid (Jeffrey fluid) over a stretching sheet with partial surface slip. The governing equations are reduced to non-linear ordinary differential equations by using a similarity transformation and then solved numerically by using Runge-Kutta-Fehlberg method. The effects of pertinent parameters on the flow and heat transfer fields are presented through tables and graphs, and are discussed from the physical point of view. Our analysis revealed that the fluid temperature is higher in case of Jeffrey fluid than that in the case of Newtonian fluid. It is also observed that the wall stress increases with increasing the values of slip parameter but the effect is opposite for the rate of heat transfer at the wall. © 2015 Faculty of Engineering, Alexandria University. Source

Singh M.K.,Tripura University | Das A.,Government General Degree College | Paul B.,Tripura University | Bhattacharjee S.,Tripura University | Sutradhar S.,Tripura University
Journal of the Indian Chemical Society

Mixed ligand complexes of NiII ion with 1,1-dicarboethoxyethylene-2,2- dithiolate [DED2- = {S2C=C(COOC2H5)2}2-] as a primary ligand and o-phenylenediamine (OPD), pyridine (py), α-picoline (α-pic), β-picoline (β-plc) or γ-picoline (γ-pic) as secondary ligands have been isolated and characterized by analytical data, molar conductance, magnetic susceptibility, electronic, infrared and fluorescence spectral studies. The molar conductance data reveal that the complexes have non-electrolytic nature in DMF solution. Magnetic and electronic spectral studies suggest distorted octahedral stereochemistry around NiII ion in its complexes. Infrared spectral studies suggest bidentate chelating behaviour of DED2- ion and OPD while other ligands show unidentate behaviour in their complexes. These complexes show fluorescence at room temperature in solid state. Source

Ghosh G.,Presidency University of India | Bose S.,Presidency University of India | Das K.,Hiroshima University | Dasgupta A.,Presidency University of India | And 5 more authors.
Journal of Structural Geology

Deformational, metamorphic, monazite age and fabric data from Rengali Province, eastern India converge towards a multi-scale transpressional deformational episode at ca. 498-521 Ma which is linked with the latest phase of tectonic processes operative at proto-India-Antarctica join. Detailed sector wise study on mutual overprinting relationships of macro-to microstructural elements suggest that deformation was regionally partitioned into fold-thrust dominated shortening zones alternating with zones of dominant transcurrent deformation bounded between the thrust sense Barkot Shear Zone in the north and the dextral Kerajang Fault Zone in the south. The strain partitioned zones are further restricted between two regional transverse shear zones, the sinistral Riamol Shear Zone in the west and the dextral Akul Fault Zone in the east which are interpreted as synthetic R and antithetic R' Riedel shear plane, respectively. The overall structural disposition has been interpreted as a positive flower structure bounded between the longitudinal and transverse faults with vertical extrusion and symmetric juxtaposition of mid-crustal amphibolite grade basement gneisses over low-grade upper crustal rocks emanating from the central axis of the transpressional belt. © 2016 Elsevier Ltd. Source

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