Investigation on Comparative Optical Absorption and Luminescent Property of Cerium Doped Potassium Halide Single Crystals
The comparison of Optical absorption, Photoluminescence (PL), Thermoluminescence (TL) and other optical studies of X-ray irradiated Ce 3+ doped KBr and KI single crystals were discussed. Photoluminescence of these crystals exhibits characteristic Ce 3+ emission due to 5d-4f transition in both the studied material in addition to the host emission. Optical absorption and PL studies confirm the presence of Cerium ions in the trivalent state in both KBr and KI host .The characteristic emission due to Ce 3+ ions in the spectral distribution under optically stimulated emission and TL emission confirms the participation of Cerium ions in the recombination process in both host material. Trap parameters for the TL process are calculated and compared.
Handbook of Lasers
SOLID STATE LASERS Introduction Crystalline Paramagnetic Ion Lasers Glass Lasers Solid State Dye Lasers Color Center Lasers Semiconductor Lasers Polymer Lasers Solid State Excimer Lasers Raman Brillouin, and Soliton Lasers LIQUID LASERS Liquid Organic Dye Lasers Rare Earth Liquid Lasers Liquid Polymer Lasers Liquid Excimer Lasers GAS LASERS Introduction Neutral Atom Gas Lasers Ionized Gas Lasers Molecular Gas Lasers Far Infrared and Millimeter Wave Gas Lasers Commercial Gas Lasers Comments References OTHER LASERS Extreme Ultraviolet and Soft X-Ray Lasers Free Electron Lasers Nuclear Pumped Lasers Natural Lasers Inversionless Lasers Amplification of Core-Valence Luminescence APPENDICES Laser Safety Acronyms, Abbreviations, Initialisms, and Common Names for Types of Lasers, Laser Materials, Laser Structures and Operating Configurations, and Systems Involving Lasers Electron Configurations of Neutral Atoms in the Ground State Fundamental Constants
Surface roughness monitoring by singular spectrum analysis of vibration signals
Abstract This study assessed two methods for enhanced surface roughness (Ra) monitoring based on the application of singular spectrum analysis (SSA) to vibrations signals generated in workpiece-cutting tool interaction in CNC finish turning operations i.e., the individual analysis of principal components (I-SSA), and the grouping analysis of correlated principal components (G-SSA). Singular spectrum analysis is a non-parametric technique of time series analysis that decomposes a signal into a set of independent additive time series referred to as principal components. A number of experiments with different cutting conditions were performed to assess surface roughness monitoring using both of these methods. The results show that singular spectrum analysis of vibration signal processing discriminated the frequency ranges effective for predicting surface roughness. Grouping analysis of correlated principal components (G-SSA) proved to be the most efficient method for monitoring surface roughness, with optimum prediction and reliability results at a lower analytical-computational cost. Finally, the results show that singular spectrum analysis is an ideal method for analyzing vibration signals applied to the on-line monitoring of surface roughness.