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Coffee certification criterion using the photoacoustic technique
Microelectronics Journal, 2008The photoacoustic (PA) technique allows a spectroscopic analysis of organic opaque samples and its thermal characterization; so this technique gives information about the pigmentation and the roasting modelling parameters, important for industry and commercialization process, when it is applied to green and powdered coffee samples, respectively.
Fernando Gordillo Delgado +2 more
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Photoacoustics: a hundred years old technique revisited
Journal of Optics, 1980A sample is heated when it absorbs light. The authors investigate the different ways of detecting the temperature increase produced by this heating in the case of solids. If the light is modulated, one can either detect mechanical vibrations induced in the fluid surrounding the solid (photoacoustic effect) or measure the deflection undergone by a laser
J Badoz, D Fournier, A C Boccara
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Skin absorption studied by photoacoustic techniques
AIP Conference Proceedings, 2000In this work we propose for the particular problem of penetration of substance into skin, a setup which is based on the conventional photoacoustic cell. In order to avoid some problems, intrinsic to the material under study and the sensibility of the technique, we use the thermal effusivity of the skin-substance system to monitor this phenomenon, in ...
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Pulsed photoacoustic technique for thermal diffusivity determination
Proceedings of IEEE Ultrasonics Symposium ULTSYM-94, 1994The paper describes an automated facility designed to measure thermal diffusivity of solids by analyzing amplitude spectrum of photoacoustic signal through fast Fourier transform. The facility includes a pulsed laser, a gas-filled microphone cell, digital storage oscilloscope, and a control unit linked to a computer via a parallel interface.
null Korobov +3 more
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Moire displacement detection by the photoacoustic technique
SPIE Proceedings, 1991Moire effect produced by the two gratings under coherent illumination attracts a high level of interest in the mask and wafer alignment for X-ray lithographic system. In such reflection optical arrangement, the displacement signal is often affected by the light reflected directly from the mask grating.
Kazuhiro Hane, S. Watanabe, Toshio Goto
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Thermal Properties Measurement Photoacoustic Technique for Hardmetals
Materials Science Forum, 2006The open photoacoustic cell technique (OPC) was carried out in order to measure the thermal diffusivity of hardmetal. Hardmetal is usually processed by the conventional powder technology techniques: mix of WC + Co powders, compacting, and liquid phase sintering A new method to process hardmetal parts is hereby described.
F.A.L. Machado +5 more
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2018
Ultrasonically probing optical absorption, photoacoustic tomography (PAT) combines rich optical contrast with high ultrasonic resolution at depths beyond the optical diffusion limit. With consistent optical absorption contrast at different scales and highly scalable spatial resolution and penetration depth, PAT holds great promise as an important tool ...
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Ultrasonically probing optical absorption, photoacoustic tomography (PAT) combines rich optical contrast with high ultrasonic resolution at depths beyond the optical diffusion limit. With consistent optical absorption contrast at different scales and highly scalable spatial resolution and penetration depth, PAT holds great promise as an important tool ...
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Recent Progress on Infrared Photoacoustic Spectroscopy Techniques
Applied Spectroscopy Reviews, 2011Abstract Analogous to most new methods in science, photoacoustic spectroscopy (PAS) grew out of an advance in technology, in this case the dramatic improvement in novel light sources, modulators, and acoustic detectors, as well as signal recovery electronics, which in turn was made possible by the development of modern PAS techniques.
Jingsong Li, Weidong Chen, Benli Yu
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Combined Photoacoustic–Acoustic Technique for Crack Imaging
International Journal of Thermophysics, 2010Nonlinear imaging of a crack by combination of a common photoacoustic imaging technique with additional acoustic loading has been performed. Acoustic signals at two different fundamental frequencies were launched in the sample, one photoacoustically through heating of the sample surface by the intensity-modulated scanning laser beam and another by a ...
J. Zakrzewski +3 more
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Technique development for photoacoustic imaging guided interventions
SPIE Proceedings, 2015Laser-induced thermotherapy (LITT), i.e. tissue destruction induced by a local increase of temperature by means of laser light energy transmission, has been frequently used for minimally invasive treatments of various diseases such as benign thyroid nodules and liver cancer. The emerging photoacoustic (PA) imaging, when integrated with ultrasound (US),
Qian Cheng +5 more
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