Aplicações de medidas de fase do efeito fotoacustico
AUTOR(ES)
Osvaldo Pessoa Junior
DATA DE PUBLICAÇÃO
1985
RESUMO
This work consists in the development of two methods of studying optical and thermal properties of materials, based on the phase of the signal of the photoacoustic effect. The method for spectra phase separation (MSf) is a simple way to isolate the photoacoustic spectra of two superimposed layers, each with a distinct absorption spectrum, using the fact that the signal of each layer has a different phase-lag. We applied this technique to biological materials (leaf and kernel of corn), and distinguished between a simple case where the method has direct application, and a general one where corrections have to be introduced. The two beam phase technique (T2F) is a new and simple method for measuring the thermal diffusivity of opaque samples based on the phase-lag between the photoacoustic signals resulting from two different chopped beams, each inciding in opposite directions. This technique was applied to six semiconducting plane-shaped samples, and the results are in good agreement with the values in literature
ASSUNTO(S)
materiais propriedades termicas analise espectral
