31 research outputs found
Effect of Radiation Absorption, Chemical Reaction and Non-Uniform Heat Source, MHD on Mixed Convective Heat and Mass Transfer Flow Past a Stretching Sheet
The objective of the present work is to investigate the combined influence of radiation absorption, chemical reaction and MHD on mixed convective heat and mass transfer flow of a viscous electrically conducting fluid past a stretching sheet in the presence of non-uniform heat source and Hall effects. The equations governing the flow of heat and mass transfer have been solved numerically employing Runge-Kutta fourth order technique together with the shooting technique. The velocity, temperature and concentration have been analyzed. The rate of heat and mass transfer on the plate has been evaluated numerically for different variations. Keywords: Hall Currents; Heat & Mass Transfer; Radiation absorption; Non-Uniform Heat Source; Soret and Dufour effects; Stretching sheet; Chemical reaction
Structural and vibrational study of pseudocubic CdIn2Se4 under compression
This document is the Accepted Manuscript version of a Published Work that appeared in final form in
Journal of Physical Chemistry C, copyright © American Chemical Society after peer review and technical editing by the publisher.
To access the final edited and published work see http://dx.doi.org/10.1021/jp5077565We report a comprehensive experimental and theoretical study of the structural and vibrational properties of a-CdIn2Se4 under compression. Angle-dispersive synchrotron X-ray diffraction and Raman spectroscopy evidence that this ordered-vacancy compound with pseudocubic structure undergoes a phase transition (7 GPa) toward a disordered rocksalt structure as observed in many other ordered-vacancy compounds. The equation of state and the pressure dependence of the Raman-active modes of this semiconductor have been determined and compared both to ab initio total energy and lattice dynamics calculations and to related compounds. Interestingly, on decreasing pressure, at similar to 2 GPa, CdIn2Se4 transforms into a spinel structure which, according to calculations, is energetically competitive with the initial pseudocubic phase. The phase behavior of this compound under compression and the structural and compressibility trends in AB(2)Se(4) selenides are discussed.This study was supported by the Spanish government MEC under Grant Nos: MAT2013-46649-C4-3-P, MAT2013-46649-C4-2-P, MAT2010-21270-C04-03/04, and CTQ2009-14596-C02-01, by MALTA Consolider Ingenio 2010 Project (CSD2007-00045) and by Generalitat Valenciana (GVA-ACOMP-2013-1012). A.M. and P.R-H. acknowledge computing time provided by Red Espanola de Supercomputacion (RES) and MALTA-Cluster, and also to S. Munoz-Rodriguez for providing a data-parsing application. J.A.S. acknowledges Juan de la Cierva fellowship program for financial support.Santamaría Pérez, D.; Gomis, O.; Pereira, ALJ.; Vilaplana Cerda, RI.; Popescu, C.; Sans Tresserras, JÁ.; Manjón Herrera, FJ.... (2014). Structural and vibrational study of pseudocubic CdIn2Se4 under compression. Journal of Physical Chemistry C. 118(46):26987-26999. https://doi.org/10.1021/jp5077565S26987269991184
Temperature behaviour of the tetragonal distortion and thermal expansion of Cu-III-VI2 chalcopyrite semiconductors
<span style="font-size: 22.0pt;mso-bidi-font-size:15.0pt;font-family:"Times New Roman","serif"; mso-bidi-font-weight:bold">Optical absorption and photoluminescence properties of Eu<sup><span style="font-size:17.5pt;mso-bidi-font-size:10.5pt; font-family:"Times New Roman","serif";mso-bidi-font-weight:bold">3</span></sup><sup><span style="font-size:17.0pt;mso-bidi-font-size:10.0pt;font-family:"Arial","sans-serif"; mso-bidi-font-weight:bold">+</span></sup><span style="font-size:17.0pt; mso-bidi-font-size:10.0pt;font-family:"Arial","sans-serif";mso-bidi-font-weight: bold"> <span style="font-size:22.0pt;mso-bidi-font-size:15.0pt; font-family:"Times New Roman","serif";mso-bidi-font-weight:bold">doped KF -B<span style="font-size:17.5pt;mso-bidi-font-size:10.5pt;font-family:"Times New Roman","serif"; mso-bidi-font-weight:bold"><sub>2</sub>O<sub>3</sub> <span style="font-size:22.0pt;mso-bidi-font-size:15.0pt;font-family:"Times New Roman","serif"; mso-bidi-font-weight:bold">glasses </span></span></span></span></span>
780-784<span style="font-size:
15.0pt;mso-bidi-font-size:8.0pt;font-family:" times="" new="" roman","serif""="">Several
physical, optical absorption and photoluminescence properties of Eu3+
doped
KF-B<span style="font-size:13.0pt;mso-bidi-font-size:6.0pt;
font-family:" times="" new="" roman","serif""="">2<span style="font-size:
13.0pt;mso-bidi-font-size:6.0pt;font-family:" times="" new="" roman","serif""="">O3
glasses
have been studied. From the measured intensities of various absorption bands of
these glasses the Judd-Ofelt parameters <span style="font-size:15.5pt;
mso-bidi-font-size:8.5pt;font-family:" arial","sans-serif""="">Ω2,
Ω4
and
Ω6,
<span style="font-size:15.0pt;mso-bidi-font-size:8.0pt;font-family:
" times="" new="" roman","serif""="">have been computed. The Judd-Ofelt theory has been
applied to characterize the photoluminescence spectra of these glasses. From
this theory various radiative properties like, transition probability (A),
branching ratio (βr) and emission cross-section (σpE)
for various emission levels of these glasses have been determined and reported.
</span
Dosimetric and kinetic parameters of lithium cadmium borate glasses doped with rare earth ions
Thermoluminescence (TL) characteristics of X-ray irradiated pure and doped with four different rare earth ions (viz., Pr3+, Nd3+, Sm3+ and Eu3+) Li2O–Cdo–B2O3 glasses have been studied in the temperature range 303–573 K; the pure glass has exhibited single TL peak at 466 K. When this glass is doped with different rare earth ions no additional peaks are observed but the glow peak temperature of the existing glow peak shifted gradually towards higher temperatures with gain in intensity of TL light output. The area under the glow curve is found to be maximum for Eu3+ doped glasses. The trap depth parameters associated with the observed TL peaks have been evaluated using Chen's formulae. The possible use of these glasses in radiation dosimetry has been described. The result clearly showed that europium doped cadmium borate glass has a potential to be considered as the thermoluminescence dosimeter. Keywords: Infrared spectra, Thermoluminescence, Borate glasses, Rare earth