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Sawitree Saengkaew Tawatchai Charinpanitkul Hathaichanok Vanisri Loïc Mees Gérard Grehan 《Optics Communications》2006,259(1):7-13
To measure the temperature of individual droplets or the average temperature in a section of a spray, the analysis of the light scattered around the rainbow angle provides an attractive approach. Up to now, the analysis of recorded rainbow signals has been carried out in the framework of the full Lorenz-Mie theory or of the Airy theory. In this paper, we consider four approaches (Lorenz-Mie, Debye, Airy and Nussenzveig approaches) to compute the light scattered around the rainbow angle, and we compare them in terms of accuracy and time-consumption. It is shown that the Complex Angular Momentum (CAM) theory proposed by Nussenzveig, modified by using empirical coefficients, allows one to accurately compute the light scattered around the rainbow angle in a large angular domain for particles with diameters as small as 10 μm. 相似文献
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Sawitree Saengkaew Tawatchai Charinpanitkul Hathaichanok Vanisri Wiwut Tanthapanichakoon Yves Biscos Nicolas Garcia Gérard Lavergne Loïc Mees Gérard Gouesbet Gérard Grehan 《Experiments in fluids》2007,43(4):595-601
The rainbow refractrometry, under its different configurations (classical and global), is an attractive technique to extract
information from droplets in evaporation such as diameter and temperature. Recently a new processing strategy has been developed
which increases dramatically the size and refractive index measurements accuracy for homogeneous droplets. Nevertheless, for
mono component as well as for multicomponent droplets, the presence of temperature and/or of concentration gradients induce
the presence of a gradient of refractive index which affects the interpretation of the recorded signals. In this publication,
the effect of radial gradient on rainbow measurements with a high accuracy never reached previously is quantified. 相似文献
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β‐Elimination coupled with strong cation‐exchange chromatography for phosphopeptide analysis
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Jiajie?Wang Gérard?GréhanEmail author Yiping?Han Sawitree?Saengkaew Gérard?Gouesbet 《Experiments in fluids》2011,51(1):149-159
The measurement of droplet temperature and size distribution in sprays is a difficult task. To reach this aim, the global
rainbow technique (GRT) has been developed on the assumption that the synthetic rainbow created by a large number of droplets
is insensitive to the non-sphericity of droplets if the droplets’ orientations were sufficiently random. In order to test
this assumption, numerical as well as experimental analyses of GRT are carried out by our team. As a companion to the work
done in experiments, the objective of this work is to quantify the sensitivity of the GRT to the non-sphericity of droplets
from a numerical aspect. Light scattering properties around the rainbow angle are investigated by using the Null-field method
within a T-matrix formulation, both for a single spheroid in an arbitrary orientation and for an ensemble of spheroids in
random orientations illuminated by a plane wave. Refractive index and size distribution of droplets are extracted from simulated
global rainbow signals so as to quantify the sensitivity of the GRT to the non-sphericity. Exemplifying results are compiled
and presented. Additionally, comparisons between the Null-field method and the generalized Lorenz-Mie theory for spheroids
are also provided in this paper. 相似文献
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Xuecheng Wu Siegfried Meunier-Guttin-Cluzel Yingchun Wu Sawitree Saengkaew Denis Lebrun Marc Brunel Linghong Chen Sébastien Coetmellec Kefa Cen Gerard Grehan 《Optics Communications》2012,285(13-14):3013-3020
Holography is an ‘old’ technique for studying the behavior of clouds of droplets which finds a new interest with CCD cameras and real-time numerical reconstruction. Furthermore, the continued progress in camera characteristics (sensitivity, pixel number, digitalization level, and so on) opens the way to more accurate recording of the interference field. To gain a deep understanding of the technique, as well as an evaluation of the performance and limitations of digital holographic particle measurements under various conditions, standard holograms are required. In this paper, a general numerical standard of holograms of fields of particles based on rigorous near-field Lorenz–Mie scattering theory is presented. This theory makes possible the computation of holograms of fields of particles with an arbitrary number of particles of arbitrary size, arbitrary refractive index, arbitrary recording distance (near-field or far-field), and an arbitrary collecting angle (forward, off-axis, or backward scattering light). Several calculation examples are also given for the code validation and possible applications, including a new possible way to simultaneously measure the size, location, and refractive index of particles. 相似文献
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Phannee Saengkaew Armin DadgarJuergen Blaesing Thomas HempelPeter Veit Juergen ChristenAlois Krost 《Journal of Crystal Growth》2009,311(14):3742-3748
We present MOVPE-grown, high-quality AlxGa1−x N layers with Al content up to x=0.65 on Si (1 1 1) substrates. Crack-free layers with smooth surface and low defect density are obtained with optimized AlN-based seeding and buffer layers. High-temperature AlN seeding layers and (low temperature (LT)/high temperature (HT)) AlN-based superlattices (SLs) as buffer layers are efficient in reducing the dislocation density and in-plane residual strain. The crystalline quality of AlxGa1−xN was characterized by high-resolution X-ray diffraction (XRD). With optimized AlN-based seeding and SL buffer layers, best ω-FWHMs of the (0 0 0 2) reflection of 540 and 1400 arcsec for the (1 0 1¯ 0) reflection were achieved for a ∼1-μm-thick Al0.1Ga0.9N layer and 1010 and 1560 arcsec for the (0 0 0 2) and (1 0 1¯ 0) reflection of a ∼500-nm-thick Al0.65Ga0.35N layer. AFM and FE-SEM measurements were used to study the surface morphology and TEM cross-section measurements to determine the dislocation behaviour. With a high crystalline quality and good optical properties, AlxGa1−x N layers can be applied to grow electronic and optoelectronic device structures on silicon substrates in further investigations. 相似文献
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