J. Phys. IV France 125 (2005) 781-783
Photoacoustic monitoring of Methylene blue irradiatedL.D. Lima1, F.R. Marciano1, M.S. Costa1, M.D. Silva2, P.R. Barja1 and D. Acosta-Avalos1
1 Instituto de Pesquisa & Desenvolvimento (IP & D), Universidade do Vale do Paraíba (UNIVAP), Av. Shishima Hifumi 2911, São José dos Campos 12244-000, SP, Brazil
2 Instituto de Pesquisas Espaciais (INPE), Av. dos Astronautas, São José dos Campos, SP, Brasil
The photoacoustic signal of methylene blue irradiated with red light (640 nm), by 1 minute, was monitored in time. It was observed that the PA signal increase with time, fact related with the diminution of the thermal effusivity of the methylene blue after irradiation. It was also observed that the signal undulates with periodicity of about 5 minutes. This behaviour is under study to better understand it.
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