Silicon oxide thin films prepared by a photo-chemical vapour deposition technique

Wide band gap a-SiO_x:H films have been prepared by the photochemical decomposition of a SiH₄, CO₂ and H₂ gas mixture. Deposition parameters namely the CO₂ to SiH₄ gas flow ratio, H₂ dilution and chamber pressure were optimized in order to achieve highly photoconducting (1 × 10^-6 S cm^-1) films with an optical gap of 1.99 eV. The optical gap was found to increase with an increase in the CO₂ to SiH₄ flow ratio. A decrease in the photoconductivity, refractive index, spin g-value and a simultaneous increase in the spin density are attributed to an incorporation of oxygen into the films. Upon hydrogen dilution the photoconductivity of a-SiO_x:H films was observed to improve along with an increase of the optical gap. The spin density of a-SiO_x:H films was of the order of 10¹⁷ cm^-9. The optoelectronic properties of the films have been correlated with the bonding configurations in the film, deposition parameters and the growth kinetics. This revised version was published online in November 2006 with corrections to the Cover Date.     

Proposed modification to the CIECAM02 colour appearance model to include the simultaneous contrast effects

A modified CIECAM02 colour appearance model, named CIECAM02‐m2, is proposed to enable CIECAM02 to predict the simultaneous contrast effect. The structure of the CIECAM02‐m2 is a development from CIECAM02, and contains two different procedures for modifying the reference white; one is for lightness and the other is for hue. The model was tested using a data set accumulated in this study and the LUTCHI data. The CV values for three colour attributes between predictions and experimental data were used to evaluate the accuracy of the model. The low CV values obtained show the performance of the CIECAM02‐m2 model to predict the simultaneous contrast effect satisfactorily. © 2007 Wiley Periodicals, Inc. Col Res Appl, 32, 121 – 129, 2007     

Monitoring Chemical Changes in Cheddar Cheese During Aging by High Performance Liquid Chromatography and Gas Chromatography Techniques

The concentrations of several chemical metabolites in Cheddar cheese were monitored by various chromatographic techniques during the aging process to learn which metabolites were the best predictors of the glycolytic, lipolytic, and proteolytic age of the cheese. Pyruvic, lactic, acetic, and propionic acids were measured by ion-exchange high performance liquid chromatography; acetone, 2-butanone, ethanol, 2-pentanone, 2-butanol, and n-propanol were monitored by headspace gas chromatography; free fatty acids were quantitated (without derivatization) by gas chromatography; and free amino acids were determined as their o-phthaldehye derivatives by high performance liquid chromatography.The best predictors of the glycolytic age were propionic acid and acetic acid; the best predictors of lipolysis were the free fatty acids C₁₀, C₁₂, C₁₄, and C₁₆; and the best predictors of proteolysis were the free amino acids leucine, methionine, and glutamic acid. The volatile metabolites determined by headspace gas chromatography were not good indicators of aging; however, they did provide useful information related to flavor problems.Cheddar cheese aged at elevated temperatures produced propionic acid, acetic acid, and free amino acids at significantly faster rates than the other chemicals that were monitored.     

III–V super-lattice SPST/SPMT pin switches for THz communication: theoretical reliability and experimental feasibility studies

Microsystem Technologies - A physics-based Quantum-Modified CLassical Drift–Diffusion (QMCLDD) non-linear mathematical model has been developed for design and characterisation of GaN/AlGaN...