Maharajas College

Ernakulam, India

Maharajas College

Ernakulam, India
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Lekshmi S.,Maharajas College | Lekshmi S.,SD College | Shaji N.,SD College
Annals of Physics | Year: 2017

We extend the definition of quantum discord as a quantifier of nonClassical correlations in a quantum state to the case where weak measurements are performed on subsystem A of a bipartite system AB. The properties of weak discord are explored for several families of quantum states. We find that in many cases weak quantum discord is identical to normal discord and in general the values of the two are very close to each other. Weak quantum discord reduces to discord in the appropriate limits as well. We also discuss the implications of these observations on the interpretations of quantum discord. © 2016 Elsevier Inc.

Sebastian R.M.,Maharajas College | Mohammed E.M.,Maharajas College
Indian Journal of Physics | Year: 2016

Nanoparticles of gadolinium substituted Mg–Zn ferrite, Mg0.75Zn0.25GdxFe2−xO4 (where x = 0.00, 0.05, 0.10, 0.15) have been prepared by the sol–gel technique. The lattice constant is found to increase with increase in the Gd3+ ion concentration. The observed variation of dielectric constant with frequency is explained on the basis of the Maxwell–Wagner two layer model and the electron hopping mechanism. The dielectric constant and dielectric loss decrease with Gd3+ ion substitution. The variation of AC conductivity with frequency suggests that the conduction is due to small polaron hopping. It is also noticed that the dielectric constant and the AC conductivity increase with temperature and it is explained in terms of the thermally enhanced drift mobility of the charge carriers. The observed low value of dielectric constant and also the dielectric loss factor obtained for gadolinium substituted ferrites make them desirable for high frequency applications. © 2016, Indian Association for the Cultivation of Science.

Rekha S.,Maharajas College | Rekha S.,Union Christian College | Anila E.I.,Union Christian College
AIP Conference Proceedings | Year: 2017

Cerium doped CaS nanophosphor was synthesized using solid state diffusion method. The structural and optical properties of the prepared nanophosphor were studied by X-ray diffractogram (XRD), diffuse reflectance spectrum (DRS) and photoluminescence (PL) spectrum. XRD pattern revealed the cubic structure of Ce doped CaS nanoparticles with average grain size 29 nm. The PL spectrum of CaS:Ce nanophosphor exhibited an emission peak at 500 nm with a shoulder peak at 556 nm which are due to the transition from 5D to 4F state of Ce3+ in the CaS crystal lattice. The optical bandgap of the sample was estimated from DRS and its value was found to be 4.59 eV. © 2017 Author(s).

Suma K.K.,Cochin University of Science and Technology | Suma K.K.,Maharajas College | Jacob S.,Cochin University of Science and Technology | Joseph R.,Cochin University of Science and Technology
Materials Science and Engineering B: Solid-State Materials for Advanced Technology | Year: 2010

Vinyl acetate-butyl acrylate (VAc-BuA) copolymer latex was prepared by emulsion polymerization. The polymerization conditions and the composition were optimized. The 85/15 wt.% (vinyl acetate/butyl acrylate) gave good tensile strength of the order of 15.6 MPa and a glass transition temperature (Tg) value of -6.49 °C. This copolymer was used as a binder in the paint formulation. In this formulation nanosized TiO2 sol was used as a pigment instead of conventional rutile TiO2. Nanosized TiO2 is prepared by wet process. These nanosized TiO2 rutile colloidal sol has improved properties such as photostability, UV shielding, dispersion stability, etc. The surface properties of paint were found to be superior compared to commercially used paint. © 2009 Elsevier B.V. All rights reserved.

Jacob B.P.,Kmm Government Womens College | Thankachan S.,Maharajas College | Xavier S.,Maharajas College | Mohammed E.M.,Maharajas College
Journal of Alloys and Compounds | Year: 2013

A series of NiTbxFe2-xO4 (x = 0.0, 0.1, 0.2, 0.3) nanoparticles with small size have been prepared using sol-gel technique. The effect of Tb3+ substitution on the crystalline phase, crystallite size and magnetic, electrical and dielectric properties has been investigated in detail. The lattice constant shows an increasing trend with increase in Tb3+ ion concentration. The high frequency tetrahedral vibration band m1 and the low frequency octahedral vibration band m2 in the FTIR spectra are in the reported range. The observed shift in m2 towards lower wave number side with increase in terbium concentration suggests the occupation of Tb3+ ions predominantly on octahedral sites. Saturation magnetization is found to decrease with terbium addition. Magnetic hysteresis loss is observed to decrease up to x = 0.2 and then increases. The room temperature resistivity values are found to increase with terbium content. The observed dielectric dispersion with frequency is explained on the basis of Maxwell-Wagner two-layer model and electron hopping mechanism which is responsible for conduction and polarization. Dielectric constant and dielectric loss are found to decrease by terbium addition and is explained in terms of the decrease in hopping rate due to the substitution of Fe3+ ions by Tb3+ ions on the octahedral sites. The increased resistivity and reduced dielectric loss attained in terbium doped ferrite is promising as it is desirable for high frequency applications. © 2013 Elsevier B.V. All rights reserved.

Suresh V.,Government Victoria College | Krishnakumar K.A.,Maharajas College | Asha V.V.,Rajiv Gandhi Center for Biotechnology
Biomedicine and Pharmacotherapy | Year: 2015

The existing screening systems for anti-hepatitis B virus (anti-HBV) drug discovery is time-consuming mainly due to the laborious detection system it is using. A new fluorescence based screening system for high throughput anti-HBV drug discovery was created by tagging hepatitis B surface antigen (HBsAg) with monomeric red fluorescent protein and hepatitis B virus (HBV) core protein with enhanced green fluorescent protein. The two constructs were co-transfected on to Hep3B cells and the transfection was stabilized by fluorescent activated cell sorter (FACS). The fusion proteins expressed through the secretory protein pathway as evidenced by localization with ER-Tracker and tubulin tracker. The new system has given analogues results like that of conventional enzyme-linked immunosorbent assay (ELISA). Hence it can be of very high potential for large scale drug screening systems. © 2015 Elsevier Masson SAS.

Thankachan S.,Maharajas College | Jacob B.P.,Maharajas College | Xavier S.,Maharajas College | Mohammed E.M.,Maharajas College
Journal of Magnetism and Magnetic Materials | Year: 2013

Samarium doped magnesium ferrite was prepared (MgSmxFe 2-xO4) by sol-gel method. X-ray diffraction analysis reveals that the samples are single phasic with crystallite sizes in the 13-25 nm regime. Increase in lattice parameter with doping concentration suggests the expansion in unit cell with Sm3+ doping. Fourier Transform Infrared Spectrum shows substitution of Sm3+ ions in octahedral B site. Transmission Electron Micrograph shows the spherical shape of nano-particles. Magnetic measurement shows a decrease in magnetization with doping which is explained using dependence on particle size. © 2013 Elsevier B.V.

Jacob B.P.,Maharajas College | Thankachan S.,Maharajas College | Xavier S.,Maharajas College | Mohammed E.M.,Maharajas College
Journal of Alloys and Compounds | Year: 2012

Terbium doped Ni-Zn ferrite, Ni 0.4Zn 0.6Tb xFe 2-xO 4 (x = 0, 0.05, 0.1, 0.15 and 0.2) have been prepared through sol-gel technique. Formation of single phase FCC spinel structure is identified in all the compositions using X-ray diffraction technique. The effect of Tb 3+ doping on the crystalline phase, crystallite size, dielectric properties and AC conductivity has been investigated in detail. Lattice constant is observed to increase with terbium content; but beyond certain concentration of terbium (x > 0.15), it decreased. DC resistivity measurements were carried out in the temperature range 300-523 K. All the compositions exhibited usual semiconducting nature of ferrites and the resistivity of the samples found to increase with terbium content up to x = 0.15. The metallic behavior of the doped samples observed in the lower temperature region is explained in terms of elastic and inelastic scattering due to the rare earth ions. The investigations on dielectric constant, dielectric loss and AC conductivity was carried out in the frequency range 100 Hz-20 MHz from room temperature to 563 K. Frequency dependence of dielectric constant showed normal behavior and is in good agreement with Koop's phenomenological theory of dielectric dispersion. AC conductivity measurements suggested conduction due to small polaron hopping. AC conductivity as well as dielectric constant is found to increase with temperature and which is due to thermally enhanced drift mobility of charge carriers. The observed decrease in dielectric loss with terbium content up to x = 0.15 is explained in terms of increase in resistivity. © 2012 Published by Elsevier B.V.

Varghese S.,Maharajas College | Muraleedharan Nair M.K.,Maharajas College
Research Journal of Pharmaceutical, Biological and Chemical Sciences | Year: 2010

The Schiff base 2-hydroxybenzilidene-3-aminophenol was synthesized and used for the preparation of coordination complexes with some transition and inner transition metals. All the compounds were characterized by elemental analysis, IR and UV spectral studies, and molar conductivity studies. The antimicrobial activities were checked against four different bacterial species E.coli, B.subtills, S.auereus and P.aeruginosa and also screened for activity against the fungus Rhizopus, the common bread mould.

Ajitha P.S.,Maharajas College | Muraleedharan Nair M.K.,Maharajas College
Research Journal of Pharmaceutical, Biological and Chemical Sciences | Year: 2010

Schiff base complexes of rare earth metals have been an interesting research field for the past few years due to their pharmacological, clinical, analytical and biological applications. Also the chemistry of antipyrine and its derivatives has been extensively investigated due to its physiological properties. The study of the metal complexes of antipyrine in antineoplastic medication, molecular biology and bioengineering has become hotspots in recent years. We report a new Schiff base formed from pyridoxal, a vitamin and 4-aminoantipyrine. Here we explore the antibacterial activity of the newly synthesized Schiff base formed from 4-aminoantipyrine with vitamin B. This Schiff base acts as a tridentate ligand, which form very stable complexes with the lanthanide metals La, Ce, Pr, Nd, Sm, Gd, Tb, Dy and Er. The structure of the ligand and complexes were characterized by elemental analysis, IR and UV spectral studies, magnetic susceptibility measurements, electrical conductance and thermo gravimetric analysis. The ligand is found to be chelating with the metal ion in a neutral tridentate manner through the carbonyl oxygen, azomethine nitrogen and the phenolic oxygen. The nitrate ions are monodentately coordinated to the metal ion. All complexes are found to have the formula, [ML2 (NO3)3]. All the studies reveal a coordination number of nine for the metals in all the complexes.

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