63,851 research outputs found
12CaO.7Al2O3 ceramic: A review of the electronic and optoelectronic applications in display devices
The alumina-based compound, 12CaO.7Al2O3, is a ceramic material with a unique cage-like lattice. Such a structure has enabled scientists to extract various new characteristics from this compound, most of which were unknown until quite recently. This compound has the ability to incorporate different anionic species and even electrons to the empty space inside its cages, thereby changing from an insulator into a conductive oxide. The cage walls can also incorporate different rare earth phosphor elements producing an oxide-based phosphor. All these characteristics are obtained without a significant change in the structure of the lattice. It is, therefore, reasonable to expect that this compound will receive attention as a potential material for display applications. This review article presents recent investigations into the application of 12CaO.7Al2O3 ceramic in various display devices, the challenges, opportunities and possible areas of future investigation into the development of this naturally abundant and environmental friendly material in the field of display.LP Displays Ltd, Blackburn, UK for partial funding of the studentship at Queen Mary, University of London. Dr Lesley Hanna of Wolfson Centre for Materials Processing, Brunel University Londo
Vibrational spectroscopic studies on crystallisation of sol-gel derived thin films of calcia-alumina binary compound
An optimized sol-gel process has been developed to produce homogeneous thin films of calcium aluminate binary (12CaO·7Al2O3) compound, on magnesium oxide substrates via spin coating. Fourier transform infrared and Raman spectroscopies have been employed to investigate the effect of annealing temperature and duration on the phase transformations in the films. Heat treatment at 1,300 °C under air atmosphere for 2 h produced single-phase 12CaO·7Al2O3 films. However, annealing at a lower temperature of 1,100 °C in air for a period of 4 h in total resulted in the crystallization of 5CaO·3Al2O3 rather than 12CaO·7Al2O3. The X-ray photoelectron spectrum of the thin film annealed at 1,300 °C corresponds to the binding energies of C12A7 compound. The annealing temperature of 1,300 °C for 2 h is found to be sufficient for formulating single phase calcia-alumina binary films in correct stoichiometric ratio of 12:7. © 2014 Springer Science+Business Media New York
Galactic longitude dependent Galactic model parameters
We present the Galactic model parameters for thin disc estimated by Sloan
Digital Sky Survey (SDSS) data of 14 940 stars with apparent magnitudes
in six intermediate latitude fields in the first Galactic
quadrant. Star/galaxy separation was performed by using the photometric
pipeline and the isodensity contours in the two colour
diagram. The separation of thin disc stars is carried out by the bimodal
distribution of stars in the histogram, and the absolute magnitudes
were evaluated by a procedure presented in the literature Bilir et al. (2005).
Exponential density law fits better to the derived density functions for the
absolute magnitude intervals and , whereas
sech/sech laws are more appropriate for absolute magnitude intervals
and . We showed that the scaleheight and
scalelength are Galactic longitude dependent. The average values and ranges of
the scaleheight and the scalelength are pc ( pc)
and pc ( pc) respectively. This result would
be useful to explain different numerical values claimed for those parameters
obtained by different authors for the fields in different directions of the
Galaxy.Comment: 28 pages, including 12 figures and 7 tables, accepted for publication
in New Astronom
The Royal Free Hospital score: a calibrated prognostic model for patients with cirrhosis admitted to intensive care unit. Comparison with current models and CLIF-SOFA score
Prognosis for patients with cirrhosis admitted to intensive care unit (ICU) is poor. ICU prognostic models are more accurate than liver-specific models. We identified predictors of mortality, developed a novel prognostic score (Royal Free Hospital (RFH) score), and tested it against established prognostic models and the yet unvalidated Chronic Liver Failure-Sequential Organ Failure Assessment (CLIF-SOFA) model
- …