Caracterização de propriedades opticas e termicas de materiais por espectroscopia fotoacustica

AUTOR(ES)
DATA DE PUBLICAÇÃO

1991

RESUMO

The photoacoustic thermal characterization of some quartz, glasses and higt-Tc superconductor samples is discussed. The physical quantity used as a thermal monitoring parameter is the thermal diffusivity, which is measured using the photoacoustic phase data. A simple "Open-Cell" configuration photoacoustic X-ray detector is experimentally demonstrated. The front air chambre of a commercial electret microphone is used as the transducer medium of conventional photoacoustic. The observed signal is well discussed by the thermal diffusion model for the photoacoustic signal. Thermal diffusivity, specific heat and electrical resistivity measurements were performed on Palladium foils with several Hydrogen concentration for one cycle and also for X = O,2H/Pd as function of the cycling number. It is shown that repeating the hydrogenation process with the sample induces aging effects heading erroneous results. The results for the thermal properties measurements on single cycled palladium samples reflected the phase transition between a-phase and b-phase as the hydrogen concentration is increased

ASSUNTO(S)

analise espectral calor - transmissão

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