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Uthrakumar R.,Loyola College | Vesta C.,SDNB Vaishnav College | Robert R.,Government Arts College Men | Mangalam G.,Dr. M.G.R. Educational and Research Institute | Das S.J.,Loyola College
Physica B: Condensed Matter | Year: 2010

The bulk single crystal of tri-nitrophenol methyl p-hydroxybenzoate (TNMPHB) of length 90 mm and diameter 12 mm was obtained by employing unidirectional growth technique. Single crystal X-ray diffraction studies and powder XRD analysis have been carried out to confirm the identity of the crystal. The optical band gap of the grown crystal was calculated to be 4.91 eV from UV transmission spectrum. The mechanical strength of the grown crystal has been studied using Vicker's microhardness tester. Low dielectric loss shows that the grown crystal contains lesser defects authenticating the suitability of the crystal towards device applications. The surface morphology studies have been carried out on the grown crystal. © 2010 Elsevier B.V. All rights reserved. Source

Radha R.,SDNB Vaishnav College | Lakshman B.,Bhaktavatsalam Memorial College for Women
Proceedings - 2014 World Congress on Computing and Communication Technologies, WCCCT 2014 | Year: 2014

This paper demonstrates a method for the detection and extraction of features like optic disc and macula from the retinal images. Digital fundus images are becoming popular for the diagnosis of ophthalmic pathologies. Due to this, there is an increasing possibility of applying digital image processing techniques and methods in these images to m the make the diagnosis more easier. In this paper first bit plane separation is done to the pre-processed retinal image. To carry the vital information of the location of optic disc and macula are found by bit plane 0 and bit plane 1. The exact boundary is identified by applying mathematical morphology. The proposed algorithm is simple and has been evaluated on the images collected from a reputed eye hospital. An accuracy of 91% was obtained in extracting the optic disc and macula from the retinal image. © 2014 IEEE. Source

Subramanian K.G.,Universiti Sains Malaysia | Hemalatha S.,SDNB Vaishnav College | Venkat I.,Universiti Sains Malaysia
ACM International Conference Proceeding Series | Year: 2012

Motivated by Watson-Crick automata, we introduce here a grammar counterpart called a Watson-Crick regular grammar that has rules as in a regular grammar but involves double stranded strings. The language generated by this grammar consists of strings in the upper strands of the double stranded strings related by a complementarity relation. We obtain some properties of these grammars and also indicate an application to generation of chain code pictures. Copyright © 2012 ACM. Source

Uthrakumar R.,Loyola College | Vesta C.,SDNB Vaishnav College | Jose M.,Loyola College | Sugandhi K.,Loyola College | And 2 more authors.
Physica B: Condensed Matter | Year: 2010

The unidirectional crystal growth technique has been employed for the bulk growth of semi-organic nonlinear optical barium bis-para-nitrophenolate para-nitrophenol tetra hydrate single crystals along the (2 2 0) direction with almost high solutecrystal conversion efficiency. The grown crystal was subjected to single crystal and powder XRD analyses in order to confirm the crystal identity. Optical absorption studies reveal very high transmittance in the entire visible and near IR region. The presence of various functional groups is confirmed by FTIR analysis. Low dielectric loss at high frequency region is indicative of enhanced optical quality with lesser defects. Photoconductivity measurements carried out on the grown crystal reveal the negative photoconducting nature. © 2010 Elsevier B.V. All rights reserved. Source

Uthrakumar R.,Sterling | Uthrakumar R.,Sri Muthukumaran Institute of Technology | Vesta C.,SDNB Vaishnav College | Bhagavannarayana G.,National Physical Laboratory India | And 2 more authors.
Journal of Alloys and Compounds | Year: 2011

Optically transparent and bulk single crystal of bis(thiourea) cadmium zinc chloride was successfully grown by unidirectional crystal growth technique. The quality of the crystal was examined by high-resolution X-ray diffraction analysis. The cell parameters and the crystallinity of the grown crystal were estimated by the single-crystal and powder X-ray diffraction analyses, respectively. Optical transmittance of the crystal was recorded using the UV-vis-NIR spectrophotometer. The optical band gap and optical constant of the material were calculated by using transmission spectrum. Microhardness measurements were made for the grown crystal using Vicker's microhardness tester. The dielectric loss and dielectric constant measurements as a function of frequency and temperature were measured for the grown crystal. © 2010 Elsevier B.V. All rights reserved. Source

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