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Infrared Spectral Range (infrared + spectral_range)

Distribution by Scientific Domains
Physics and Astronomy75%

Selected Abstracts

Particle surface temperature measurements with multicolor band pyrometry

AICHE JOURNAL, Issue 1 2009
Hong Lu
Abstract A noncontact, color-band pyrometer, based on widely available, inexpensive digital imaging devices, such as commercial color cameras, and capable of pixel-by-pixel resolution of particle-surface temperature and emissivity is demonstrated and described. This diagnostic instrument is ideally suited to many combustion environments. The devices used in this method include color charge-coupled device (CCD), or complementary metal oxide semiconductor (CMOS) digital camera, or any other color-rendering camera. The color camera provides spectrally resolved light intensity data of the image, most commonly for three color bands (Red, Green, and Blue,), but in some cases for four or more bands or for a different set of colors. The CCD or CMOS sensor-mask combination has a specific spectral response curve for each of these color bands that spans the visible and often near infrared spectral range. A theory is developed, based on radiative heat transfer and camera responsivity that allows quantitative surface temperature distribution calculation, based on a photograph of an object in emitted light. Particle surface temperature calculation is corrected by heat transfer analysis with reflection between the particle and reactor wall for particles located in furnace environments, but such corrections lead to useful results only when the particle temperature is near or below the wall temperatures. Wood particle-surface temperatures were measured with this color-band pyrometry during pyrolysis and combustion processes, which agree well with thermocouple measured data. Particle-surface temperature data simultaneously measured from three orthogonal directions were also mapped onto the surface of a computer generated 3-D (three-dimensional) particle model. © 2008 American Institute of Chemical Engineers AIChE J, 2009 [source]

Characterization of the respiration of 3T3 cells by laser-induced fluorescence during a cyclic heating process

LASER PHYSICS LETTERS, Issue 4 2010
J. Beuthan
Abstract The use of lasers in the near infrared spectral range for laser-induced tumor therapy (LITT) demands a new understanding of the thermal responses to repetitive heat stress. The analysis of laser-induced fluorescence during vital monitoring offers an excellent opportunity to solve many of the related issues in this field. The laser-induced fluorescence of the cellular coenzyme NADH was investigated for its time and intensity behavior under heat stress conditions. Heat was applied to vital 3T3 cells (from 22 °C to 50 °C) according to a typical therapeutical time regime. A sharp increase in temperature resulted in non-linear time behavior when the concentration of this vital coenzyme changed. There are indications that biological systems have a delayed reaction on a cellular level. These results are therefore important for further dosimetric investigations. (© 2010 by Astro Ltd., Published exclusively by WILEY-VCH Verlag GmbH & Co. KGaA) [source]

Optical properties of NiCrOx thin films

PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 5 2008
Nora Dahmouchène
Abstract The optical properties of thin NiCrOx layers were investigated by spectroscopic ellipsometry (SE). The layers were coated on float glass by magnetron sputtering at different oxygen partial pressures (20% to 30% oxygen in the sputtering gas) and the influence of the degree of oxidation was considered in details. The optical constants of the films n and k, in the visible to near infrared spectral range (0.35 to 1.7 mm), appear to be extremely sensitive to their chemical composition. Complementary studies were carried out using Fourier transform infrared ellipsometry (FTIR-SE) to determine the optical conductivity of the films and compare it with four-points-probe measurements. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Effect of form anisotropy of silicon nanocrystals on birefringence and dichroism in porous silicon

PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 6 2007
A. I. Efimova
Abstract Artificial anisotropic optical media based on nanostructured silicon formed by electrochemical porosifying of Si substrates are investigated. Strong birefringence and dichroism of surface silicon-hydrogen bonds vibrations are found in the infrared spectral range. A comprehensive analysis of the absorption bands corresponding to the deformation and stretching modes is performed. The experimental results are discussed in terms of an effective medium model, taking into account the morphological anisotropy of Si nanocrystals in porous Si layers. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]