National College Autonomous

Tiruchirappalli, India

National College Autonomous

Tiruchirappalli, India
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Shanmugam P.,National College Autonomous | Pari S.,National College Autonomous
Optik | Year: 2016

Single crystals of undoped and rhodamine-B doped l-alanine acetate have grown from solution by slow evaporation method at room temperature (30 °C). The title samples were synthesized and purified by repeated re-crystallization process. Solubility of the samples in water was found at different temperatures. The crystals were characterized by single crystal X-ray diffraction and Fourier Transform Infrared Spectroscopic (FTIR) analysis. The range and percentage of optical transmission was ascertained by recording UV-vis-NIR spectra and the optical band gap was determined. The second harmonic generation behavior of the samples was tested by Kurtz-Perry powder technique. Mechanical hardness, yield strength and stiffness constant were estimated by Vickers microhardness method. Laser damage threshold values were found out using Nd:YAG laser for the grown crystals. EDAX analysis was done to identify elements present in the undoped and rhodamine-B doped l-alanine acetate crystals. Dielectric constant and dielectric loss of the samples were estimated to understand the polarization processes and insulating behavior in the samples. TG/DTA studies were carried out to find the thermal stability and photoluminescence spectra were recorded for the samples to find the optical emission bands. © 2015 Elsevier GmbH. All rights reserved.

Senthamilselvi V.,Kunthavai Naachiyaar Government College for Women Autonomous | Senthamilselvi V.,AVVM Sri Pushpam College Autonomous | Saravanakumar K.,AVVM Sri Pushpam College Autonomous | Anandhi R.,AVVM Sri Pushpam College Autonomous | And 3 more authors.
Journal of Materials Science: Materials in Electronics | Year: 2012

CdS films were fabricated using Successive Ionic Layer Adsorption and Reaction (SILAR) technique from starting solutions having S:Cd ratio 1:1, 3:1, 5:1 and 7:1 and their structural, surface morphological and optical properties were investigated and compared with that of their chemical bath deposited counterparts. The X-ray diffraction profiles showed that the films have cubic crystal structure with preferential orientation along the (111) plane and the intensity of the (111) plane increases for both the techniques as the S:Cd ratio increases. The energy dispersive X-ray analysis revealed that for SILAR deposited films, the S/Cd ratio in the sample increases from 0.8308 (for S:Cd 1:1) to 1.04 (for S:Cd 7:1) as the molar concentration of sulphur in the starting solution increases. But for CBD films, the S/Cd is only ∼0.80 for all concentrations of sulphur in the starting solution. The optical band gap increases with the increase in S:Cd ratio in the starting solution in both the techniques. © 2011 Springer Science+Business Media, LLC.

PubMed | Bharathidasan University, Autonomous University of Puebla and National College Autonomous
Type: Journal Article | Journal: Acta crystallographica. Section E, Crystallographic communications | Year: 2016

In the title compound, C

Senthamilselvi V.,Kunthavai Naachiyaar Government College for Women Autonomous | Senthamilselvi V.,P.A. College | Saravanakumar K.,P.A. College | Anandhi R.,P.A. College | And 2 more authors.
Optoelectronics and Advanced Materials, Rapid Communications | Year: 2011

Good quality CdS films were deposited on glass substrates by the simple and inexpensive SILAR (Successive Ionic Layer Adsorption and Reaction) technique from aqueous solutions having different S:Cd ratios (1:1, 3:1, 5:1 and 7:1). The annealing induced changes in the structural, surface morphological, elemental and optical properties were studied and reported. The X-ray diffraction studies revealed that a phase transformation from cubic or mixed phase to the pure hexagonal phase was caused by the annealing process at 350°C and the degree of crystallinity was enhanced very much due to annealing. The recrystallization induced by the annealing process improved the S/Cd ratio in the films and thereby made the films to acquire good stoichiometry suitable for photovoltaic applications. The annealed films found to have better transmittance (>85 %) in the visible region and enhanced optical band gap (2.50 eV).

Mangaiyarkarasi K.,National College Autonomous | Ravichandran A.T.,National College Autonomous
International Journal of ChemTech Research | Year: 2014

L-Phenylalaninium Acetate single crystal was grown by conventional method.L- Phenylalanine and Acetic acid was taken in 1:1 ratio and dissolved in distilled water, the saturated solution was prepared by the magnetic stirrer, Then the solution was kept for controlled evaporation after 20 days the LPAA single crystals were harvested. The grown crystal was examined by Powder XRD, FTIR, UV, TG/DTA and Microhardnes test and the results were discussed. From the XRD the structure of the crystal and the parameters of the crystal were founded. From UV the transparency and the cut-off wavelength were calculated. The stability of the crystal was confirmed by TG/DTA analysis.

Ravichandran A.T.,National College Autonomous | Catherine Siriya Pushpa K.,National College Autonomous | Ravichandran K.,AVVM Sri Pushpam College Autonomous | Karthika K.,AVVM Sri Pushpam College Autonomous | And 3 more authors.
Superlattices and Microstructures | Year: 2014

Undoped and Al (2-10 mol.%) doped ZrO2 nanopowders were synthesized using solution combustion method having glycine as the fuel in a pre-heated furnace of around 500 °C. XRD study reveals that the synthesized nanopowders exhibit tetragonal phase of ZrO2 and also confirm the decrease in the crystallite size with the increase in the Al doping level. The lattice fringes observed from the HRTEM image substantiate the phase of the synthesized material. EDAX study confirms the presence of the elements Zr, Al, O in the nanopowders and the appropriate increase in the Al proportion in the final product. The FTIR and the absorption spectra clearly confirm that the product is ZrO2 with tetragonal structure. The band gap of the synthesized nanopowders is found to be around 5.1 eV. From PL spectra, the defect levels present in the product are analyzed and reported. © 2014 Elsevier Ltd. All rights reserved.

Sekar K.G.,National College Autonomous | Periyasamy S.K.,National College Autonomous
Arabian Journal of Chemistry | Year: 2013

The kinetics of oxidation of thioglycolic, thiolactic and thiomalic acids by quinaldinium fluorochromate [QnFC] has been studied in non aqueous medium. The oxidation kinetics was followed spectrophotometrically in the temperature range of 30-60 °C. The reaction shows unit order dependence each with respect to substrate and oxidant. The reaction is catalysed by hydrogen ions. The hydrogen ion dependence takes the form kobs = a + b [H+]. The reaction rate decreases with increasing the concentration of Mn2+ ions. The reaction does not induce polymerization of acrylonitrile. A plausible mechanism has been proposed for the formation of a thioester and its decomposition which occur in the slow step. © 2013 King Saud University.

Ramasamy R.,National College Autonomous
Journal of Applied Spectroscopy | Year: 2013

Solid phase FTIR and FT-Raman spectra of pyridoxazinone have been recorded in regions of 4000-50 cm-1 and 3500-100 cm-1 respectively. The spectra were interpreted by normal coordinate analysis following full structure optimizations and force field calculations based on density functional theory (DFT) using the standard B3LYP/6-31G* and B3LYP/6-311+G** method and basis set combinations. The results of the calculations are applied to simulate infrared and Raman spectra of the title compound, which showed excellent agreement with the observed spectra. © 2013 Springer Science+Business Media New York.

Vivekanandan K.,National College Autonomous | Lakshmi Narayanan R.,National College Autonomous
Der Pharma Chemica | Year: 2016

The oxidation of an essential amino acid like lysine by nicotinium dichromate in aqueous medium in the presence of perchloric acid was studied. The reaction was first order with respect to oxidant, fractional order with respect to substrate and second order with respect to perchloric acid. The increase in ionic strength had negligible effect on the rate. Amino acid was converted to the corresponding carbonyl compound. No polymerisation was observed with acrylonitrile. The addition of Mn2+ ion had a noticeable catalytic effect on the rate. The rates were determined at four different temperatures and the thermodynamic parameters were evaluated.

Muruganantham G.,P.A. College | Ravichandran K.,P.A. College | Saravanakumar K.,P.A. College | Ravichandran A.T.,National College Autonomous | Sakthivel B.,P.A. College
Superlattices and Microstructures | Year: 2011

Undoped and fluorine doped tin oxide films were deposited from starting solutions having different values of solvent volume (10-50 ml) by employing a low cost and simplified spray technique using perfume atomizer. X-ray diffraction studies showed that there was a change in the preferential orientation from (2 1 1) plane to (1 1 0) plane as the volume of the solvent was increased. The sheet resistance (Rsh) of undoped SnO2 film was found to be minimum (13.58 KΩ/□) when the solvent volume was lesser (10 ml) and there was a sharp increase in Rsh for higher values of solvent volume. Interestingly, it was observed that while the R sh increases sharply with the increase in solvent volume for undoped SnO2 films, it decreases gradually in the case of fluorine doped SnO2 films. The quantitative analysis of EDAX confirmed that the electrical resistivity of the sprayed tin oxide film was mainly governed by the number of oxygen vacancies and the interstitial incorporation of Sn atoms which in turn was governed by the impinging flux on the hot substrate. The films were found to have good optical characteristics suitable for opto-electronic devices. © 2011 Elsevier Ltd. All rights reserved.

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