El Instituto Politécnico Nacional
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http://repositoriodigital.ipn.mx/handle/123456789/11572| Título : | Differential sensor in front |
| Palabras clave : | magnitude differential methods |
| Fecha de publicación : | 16-ene-2013 |
| Editorial : | JOURNAL OF PHYSICS D: APPLIED PHYSICS |
| Descripción : | In this paper the theory of the differential front photopyroelectric technique is developed. The
thermal effusivity measurements of a sample through photopyroelectric direct (no-differential)
experiments do not have sufficient resolution and accuracy to detect small changes in the
thermal effusivity. To assess minor variations in this thermal magnitude, differential methods
should be used. These methods compare properties of a reference sample and another
unknown sample, which are placed separately in both halves of the differential cell. It is
shown that in order to achieve better metrological properties of the differential measurement
and electromagnetic interference immunity, the signals of both halves must be subtracted
directly at the output of the two parallel connected pyroelectric sensors. The thickness of the
samples should have the maximum possible value, at least 10 times higher than the thermal
diffusion length for minimum frequency. The results of numerical simulations for the
amplitude, phase, real and imaginary parts with water as a reference sample and the other
sample with a thermal effusivity very close to that of water (contaminated water) are
presented. These results show that measurements should be made in the nearly ideal voltage
mode, which ensures a better signal-to-noise ratio than the ideal current mode Instituto politecnico Nacional CONACYT |
| URI : | http://www.repositoriodigital.ipn.mx/handle/123456789/11572 |
| Otros identificadores : | http://hdl.handle.net/123456789/1112 |
| Aparece en las colecciones: | Doctorado |
Ficheros en este ítem:
| Fichero | Descripción | Tamaño | Formato | |
|---|---|---|---|---|
| JPD_Marin_2008.pdf | 35.03 kB | Adobe PDF | Visualizar/Abrir |
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