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Sivaramamoorthy K.,Rajapalayam Rajus College | Asath Bahadur S.,Kalasalingam University | Kottaisamy M.,Kalasalingam University | Murali K.R.,CECRI
Crystal Research and Technology | Year: 2010

CdSxSe1-x films were deposited by the electron beam evaporation technique on glass substrates at different temperatures in the range 30-300 °C using the laboratory synthesized powders of different composition. The films exhibited hexagonal structure and the lattice parameters shifted from CdSe to CdS side as the composition changed from CdSe to CdS side. The bandgap of the films increased from 1.68 to 2.41 eV as the concentration of CdS increased. The root-mean-roughness (RMS) values are 3.4, 2.6, 1.2 and 0.6 nm as the composition of the films shifted towards CdS side. The conductivity varies from 30 ωcm-1 to 480 ωcm-1 as the 'x' value increases from 0 to 1. The films exhibited photosensitivity. The PL spectrum shifts towards lower energies with decreasing x, due to the decrease of the fundamental gap with Se composition. © 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.


Kobayashi A.,Osaka University | Subramanian B.,CECRI
Key Engineering Materials | Year: 2013

Chemical structure of hydroxyapatite (HA) is very close to human bone which makes it compatible with the tissue of the human body. Its good biocompatibility makes it to be used extensively in many prosthetic applications, especially as a porous material for optimal bone in growth. Currently, this material is being deposited on bio-inert metallic implants and used as recovery parts in human body. In this present study a high-power plasma jet known as gas tunnel type plasma torch (GTTP), was used to produce HA and YSZ reinforced HA coatings on stainless steel substrate. In this study, microstructure, tribological properties and bioactivity of the GTTP sprayed HA and YSZ reinforced HA coatings was investigated. The XRD spectra of the as-sprayed coatings showed that the as-sprayed pure HA coating retained its crystalline HA phase similar to the initial feed stock HA powder, even though there existed a possibility for occurrence of decomposition during its in-flight in high temperature plasma zone. In the present case the decomposition processes of in-flight HA could be well controlled by means of selective operating parameters and unique nature of GTTP jet. The presence of un-melted particles and pores inside the coating microstructure play a vital role in the bonding strength of the coating. © (2013) Trans Tech Publications, Switzerland.


John Berchmans L.,CECRI
Journal of Materials Science: Materials in Electronics | Year: 2013

Zn1-2xCoxMnxO (x = 0.03 and 0.05) bulk samples were synthesised by a standard high temperature solid state reaction technique at 1,400 C. Characterization techniques X-ray diffraction, Vibrating Sample Magnetometry and Scanning Electron Microscopy with Energy Dispersive Analysis of X-rays were used to investigate effect of transition metal element Co and Mn incorporated in the system using high temperature technique. The magnetic, structural, electron density distribution and bonding properties have been investigated for the samples prepared in this work. X-ray diffraction analysis of the synthesized samples showed a single phase ZnO wurtzite structure for x = 0.03 and very slight segregation of a spinel phase for x = 0.05. Magnetization measurements indicate no evidence of ferromagnetism in co-doped (Co and Mn) ZnO. The structural and electron density analysis presented in this work is based on the actual concentrations of Co and Mn ions introduced in the matrix which nearly coincide with the nominal concentrations. © 2013 Springer Science+Business Media New York.


Francis S.,Madura College | Saravanan R.,Madura College | Berchmans L.J.,CECRI
Journal of Electronic Materials | Year: 2013

In this study, Co-doped Zn1-x Co x O (x = 0.04, 0.06, 0.08, and 0.10, where x is the concentration of guest atom cobalt in the ZnO lattice) bulk samples were examined to determine the effect of doping on electronic, structural, magnetic, and optical properties. The samples were prepared using a standard high-temperature solid-state reaction technique. All samples were characterized by x-ray diffraction (XRD), magnetization measurements using vibrating-sample magnetometry (VSM), optical absorption spectroscopy, and scanning electron microscopy (SEM) with energy-dispersive x-ray spectroscopy (EDAX). The electron densities derived from the maximum-entropy method (MEM) show an improvement of electronic charge densities with Co impurity addition. The magnetic measurements at room temperature show variations in ferromagnetic behavior with respect to Co addition. The optical study shows a decrease in energy gap of ZnO with increasing cobalt content. © 2013 TMS.


Samir O.M.,Ibb University | Madhu S.,CECRI | Somashekar R.,University of Mysore
Fibers and Polymers | Year: 2010

The lowland and coastal regions are the areas where cotton is cultivated in Yemen. The land used for this purpose exceeds 120 acres and expandable in the upcoming seasons. We have selected the earlier two varieties of cotton fibers cultivated in two different areas Abyan and Zabid. Wide Angle X-ray Scattering (WAXS) data from these fibers have been recorded and analysed to obtain the micro-structural parameters with the application of Line Profile Analysis (LPA). Linked Atom Least Squares (LALS) program has been used to obtain molecular structure and packing in these fibers. For the first time micro-structural parameters of these cotton fibers cultivated in Yemen are computed and reported. This study will be of help to understand the structure-property relation in these cotton fibers. © 2010 The Korean Fiber Society and Springer Netherlands.

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