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Patna, India

The National Institute of Technology Patna , formerly Bihar School of Engineering and Bihar College of Engineering, is a public engineering institution located in Patna in the Indian state of Bihar. It was renamed to NIT Patna, by the Government of India on January 28, 2004. It is an autonomous institute functions directly under Ministry of Human Resource Development, Government of India. Wikipedia.

Mahato D.K.,National Institute of Technology, Patna | Sinha T.P.,Bose Institute of India
Journal of Materials Science: Materials in Electronics | Year: 2013

The polycrystalline praseodymium zinc zirconate Pr2ZnZrO 6 (PZZO) is synthesized at 1,150 C by means of solid state reaction technique. X-ray structural analysis confirmed the formation of a single phase monoclinic structure at room temperature. The nonzero intercept in the Nyquist plot indicates the presence of an arc for frequency higher than the maximum frequency measured (1 MHz). Comparative study of the impedance and modulus plot confirm the contribution from grain and grain-boundary and grain-boundary contribution dominates in the material. The activation energy of the compound calculated from imaginary part of impedance plot is found to be 0.442 eV which suggests that the polaron hopping is responsible for conduction mechanism in PZZO. Semiconducting behavior of the material is observed. Summerfield scaling shows a quite satisfying overlap of the data at different temperatures on a single master curve. © 2013 Springer Science+Business Media New York.

Mahato D.K.,National Institute of Technology, Patna | Sinha T.P.,Bose Institute of India
Journal of Alloys and Compounds | Year: 2015

Sample of Pr2CoZrO6 (PCZ) was synthesized through the standard solid state reaction method. X-ray diffraction experiments and least square-like analysis reveal that the material crystallizes in an orthorhombic structure. SEM image displayed well-defined regular shaped spherical grains with average grain-size 0.615 μm. Frequency dependence of impedance and electric modulus properties are studied over a wide frequency range of 44 Hz to 1 MHz at various temperatures to confirm the contribution from grain and grain-boundary. Impedance data are presented in the Nyquist plot which is used to identify an equivalent circuit and fundamental circuit parameters. Scaling behavior of the impedance data suggests that the relaxation describes the same mechanism at various temperatures. The ac conductivity data has been analyzed by fitting the data into Jonscher power law and the conduction in this system is interpreted as due to small polaron hopping. Summerfield scaling plot is used to investigate Arrhenius temperature dependence of conductivity. © 2015 Published by Elsevier B.V.

Choudhary M.,National Institute of Technology, Patna | Patel R.N.,A.P.S. University | Rawat S.P.,A.P.S. University
Journal of Molecular Structure | Year: 2014

Three new copper (II) complexes viz. [Cu(L1)(bipy)] ×2H2O 1, [Cu(L1)(dmp)]×CH3CN 2, [Cu(L1)(phen)] 3 where L1H2 = 2-{[(Z)-(5-bromo-2-hydroxyphenyl)methylidene]amino}benzoic acid, bipy = 2,2′-bipyridine; dmp = 2,9-dimethyl 1,10-phenanthroline, phen = 1,10-phenanthroline have been synthesized and characterized by physic-chemical and spectroscopic methods. The solid-state structures of 1 and 2 were determined by single crystal X-ray crystallography, which revealed distorted square pyramidal geometry. In solid-state structure, 1 is self-assembled via intermolecular π.π stacking and the distances between centroids of aromatic ring is 3.525 Å. L1H2 is a diprotic tridentate Schiff base ligand having ONO donor site. Infrared spectra, ligand field spectra and magnetic susceptibility measurements agree with the observed crystal structures. The EPR spectra of these complexes in frozen DMSO solutions showed a single at g ca. 2. The trend in g-value (g|| > g ⊥ > 2.0023) suggests that the unpaired electron on copper (II) has dx2-y2 character. Copper (II) complexes 1-3 yielded an irreversible couple corresponding to the Cu (II)/Cu (I) redox process. Superoxide dismutase activity of all these complexes has been revealed to catalyze the dismutation of superoxide (O2-) and IC50 values were evaluated and discussed. Antimicrobial and antifungal activities of these complexes were also investigated. © 2013 Elsevier B.V. All rights reserved.

Khan M.N.,Indian Institute of Technology Patna | Pal S.,Indian Institute of Technology Patna | Parvin T.,National Institute of Technology, Patna | Choudhury L.H.,Indian Institute of Technology Patna
RSC Advances | Year: 2012

In this paper, we have described a simple and convenient method for the one-pot multicomponent reaction of aldehydes, malononitrile and thiols in the presence of a catalytic amount of Bronsted base potassium hydroxide for the efficient synthesis of highly functionalized pyridines. The notable features of this protocol are the simple experimental procedure, short reaction time, broad substrate scope and good yields using a catalytic amount of readily available and cheap base. The photophysical behaviours of the synthesized pyridines have been investigated by UV-Vis and fluorescence spectroscopy and some of the synthesized substituted pyridines exhibit promising fluorescence quantum yields. © 2012 The Royal Society of Chemistry.

Mahato D.K.,National Institute of Technology, Patna | Dutta A.,Bose Institute of India | Sinha T.P.,Bose Institute of India
Physica B: Condensed Matter | Year: 2011

Double perovskite oxide holmium zinc zirconate Ho2ZnZrO 6 (HZZ) is synthesized by solid state reaction technique under a calcination temperature of 1100°C. The crystal structure has been determined by powder X-ray diffraction, which shows monoclinic phase at room temperature. The variation of dielectric constant (ε′) and loss tangent (tan δ) with frequency is carried out assuming a distribution of relaxation times. The frequency corresponding to loss tangent peak is found to obey an Arrhenius law with activation energy of 89.7 meV. The frequency-dependant electrical data are analyzed in the framework of conductivity and electric modulus formalisms. Both these formalisms show qualitative similarities in relaxation times. The scaling behaviour of imaginary electric modulus shows the temperature-independent nature of the distribution of relaxation times. Nyquist plots are drawn to identify an equivalent circuit and to know the bulk and interface contributions. © 2011 Elsevier B.V. All rights reserved.

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