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Shrivastava R.,Shri Shankaracharya Engineering College | Singh R.S.,Government D T College | Singh A.K.,Government Vyt Pg Autonomous College
Materials Research Express | Year: 2015

In this paper, a comparative study of CdZnS nano-crystalline films with two different capping agents, CTAB and TSC, deposited by chemical bath deposition method has been made using x-ray diffraction, scanning electron microscope, transmission electron microscopy and atomic frequency microscopy. The structure of CdZnS nano-crystalline films with capping agents CTAB and TSC was observed by XRDtechnique and found to be both hexagonal and cubic. SEM micrographs show the cabbage-like structure of CdZnS nano-crystalline films when prepared in the presence of capping agents. TheAFM image shows the presence of nanorods in the samples. TheTEMdiffraction pattern indicates a nanocrystalline structure with the presence of various crystal planes. Elemental analysis has also been made and it has been found that no impurity was present in the film. © 2015 IOP Publishing Ltd. Source


Gupta N.,Government Vyt Pg Autonomous College | Pillai A.K.,Government Vyt Pg Autonomous College | Parmar P.,Shri Shankaracharya Engineering College
Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy | Year: 2015

A novel, sensitive, selective and simple kinetic spectrophotometric method has been developed for determination of trace levels of carbaryl based on its inhibitory effect on the oxidation of rhodamine-B by chlorine and bromine released from reaction of potassium bromate with hydrochloric acid in micellar medium. A linear relationship was observed between the inhibitory effect and the concentration of the compound. The absorbance was monitored at the maximum wavelength of 555 nm. The effect of different parameters such as pH, temperature and concentration of rhodamine-B, potassium bromate and surfactant on the reaction were investigated and optimum conditions were established. Under the selected experimental conditions, carbaryl was determined in the range of 0.04-0.4 μg mL-1. Sandell's sensitivity and molar absorptivity were found to be 0.00055 μg cm-2 and 3.658 × 105 L mol-1 cm-1 respectively. The proposed method was applied satisfactorily for the determination of carbaryl in water and different grain samples. The results were compared with those obtained by reference method and were found to be in agreement. © 2014 Elsevier B.V. All rights reserved. Source


Shrivastava R.,Shri Shankaracharya Engineering College | Singh R.S.,Government D T College | Singh A.K.,Government Vytpg Autonomous College
Indian Journal of Physics | Year: 2015

Cerium-doped cadmium zinc sulfide nanoparticles (CdZnS:Ce) were synthesized by chemical bath deposition method with three different concentrations of cerium (1.2, 2.5 and 3.84 mol%). X-ray diffraction pattern revealed the formation of cadmium zinc sulfide nanoparticles with cubic and hexagonal structure. It was observed that the presence of ceria did not alter the structure of CdZnS. Average crystallite size was measured from X-ray diffraction data by using Scherrer’s formula. From the study of absorption spectra, band-to-band absorption was obtained at 455 and 470 nm, respectively, for the Ce-doped (2.5 and 3.84 mol%) CdZnS nanoparticles. Energy band gap for undoped and Ce-doped CdZnS varied from 3.45 to 3.15 eV with error ±0.05 eV. The presence of cerium was confirmed by energy-dispersive analysis of X-rays. The effect of dopant concentration on the photoluminescence intensity was also studied. The photoluminescence emission peak was observed at 520, 540 and 560 nm, respectively, for the Ce-doped (1.2, 2.5 and 3.84 mol%) CdZnS nanoparticles. X-ray diffraction and photoluminescence analysis demonstrated that the Ce3+ ions uniformly substituted Cd2+ sites or interstitial sites in CdZnS lattice, which influenced the optical properties. An increase in the concentration of cerium shifted the UV–Vis absorption spectra and photoluminescence emission spectra toward the higher wavelength side. Particle size and the crystallinity of CdZnS:Ce nanoparticles were confirmed through transmission electron microscopy and selected area electron diffraction patterns. © 2015, Indian Association for the Cultivation of Science. Source


Shrivastava R.,Shri Shankaracharya Engineering College
Bulletin of Materials Science | Year: 2015

Tin (Sn)-doped cadmium zinc sulphide nanoparticles (CdZnS: Sn) were synthesized by the chemical bath deposition method with two different concentrations of Sn (2 and 4 mol%). X-ray diffraction (XRD) pattern reveals the formation of CdZnS nanoparticles with cubic and hexagonal structure. It was observed that the presence of Sn does not alter the structure of CdZnS. Average crystallite size was measured from XRD data by using Scherrer's formula. From the study of absorption spectra, band-to-band absorption was obtained at 460 and 490 nm, respectively, for the Sn-doped (2 and 4 mol%) CdZnS nanoparticles. Energy bandgap for undoped and Sn-doped CdZnS varies from 3.5 to 2.9 eV with error ± 0.05 eV. The presence of Sn was confirmed by energy-dispersive X-ray analysis. The effect of dopant concentration on the photoluminescence (PL) intensity has also been studied. The PL emission peak has been observed at 540, 550 and 560 nm for the Sn-doped (CdZnS, CdZnS 2 mol% and CdZnS 4 mol%), respectively, nanoparticles. XRD and PL analyses demonstrate that the Sn2+ ions uniformly substitute Cd2+ sites or interstitial sites in CdZnS lattice, which influence the optical properties. Increase in the concentration of Sn shifts the UV-vis absorption spectra and PL emission spectra towards higher wavelength side. Particle size and the crystallinity of CdZnS: Sn nanoparticles were confirmed through atomic force microscopy. © 2015 Indian Academy of Sciences. Source


Goswami G.K.,Kalyan Post Graduate College | Yadav A.K.,Galgotias University | Mishra M.,Shri Shankaracharya Engineering College
International Journal of Theoretical Physics | Year: 2014

In the present work, we have searched the existence of ΛCDM-type cosmological model in anisotropic Heckmann-Schucking space-time. The matter source that is responsible for the present acceleration of the universe consist of cosmic fluid with p = ωiρ, where ωi is the equation of state parameter for different cosmic fluids. The Einstein’s field equations have been solved explicitly under some specific choice of parameters that isotropizes the model under consideration. It has been found that the derived model is in good agreement with recent SN Ia observations. Some physical aspects of the model has been discussed in detail. © 2014, Springer Science+Business Media New York. Source

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