Net emission coefficients were calculated for a two-dimensional HID light source in accordance with the composition, the local temperature, and the radiation relative to the rest of the discharge which can be absorbed in the same volume of an element. All important line-broadening mechanisms were included, and the effects of emission and absorption on the net emission coefficient were accounted for on a line-by-line basis. Particular attention has been paid to the effect of pressure on the net emission of the 253.7 nm resonance line and the visible lines.
This paper shows the implementation of the Discrete Ordinates Method for handling radiation problems in High Intensity Discharge (HID) lamps. Therefore, we start with presenting this rigorous method for treatment of radiation transfer in a two-dimensional, axisymmetric HID lamp. Furthermore, the finite volume method is used for the spatial discretization of the Radiative Transfer Equation. The atom and electron densities were calculated using temperature profiles established by a 2D semi-implicit finite-element scheme for the solution of conservation equations relative to energy, momentum, and mass. Spectral intensities as a function of position and direction are first calculated, and then axial and radial radiative fluxes are evaluated as well as the net emission coefficient. The results are given for a HID mercury lamp on a line-by-line basis. A particular attention is paid on the 253.7 nm resonance and 546.1 nm green lines.
In this work, Al2O3 coating effect on morphology, structure and optoelectronic properties of Si/SnO2/Al2O3 porous matrix composites (PMCs) were investigated. A three-staked thin layers deposited on a ⟨100⟩ oriented silicon substrate made these composites. First, porous silicon layers were achieved by electrochemical etching method. Then Al2O3 and SnO2 layers were successively deposited by physical and chemical vapor deposition, respectively. Morphological and micro-structural properties of the as prepared composites were evaluated by Scanning electron microscope, energy dispersive X-ray spectroscopy and X-ray diffraction. Results proved that Al2O3 concentration alters notably the porosity of the PMCs.Variable angle spectroscopic ellipsometry (SE) revealed a high correlation between the optical constants (n, k) and the PMC microstructure. Impedance spectroscopy revealed a semiconductor-metallic transition at high frequency in the temperature range between 340 to 410°C.
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