Determination of object shape and reflectance based on Moiré system using multiple light sources and a reflection model

2006 ◽  
Vol 37 (6) ◽  
pp. 32-43
Author(s):  
Shoichi Naganuma ◽  
Norio Tagawa ◽  
Akihiro Minagawa ◽  
Tadashi Moriya
Keyword(s):  
Light Sources ◽  
Object Shape ◽  
Reflection Model

scholarly journals Multivariate Analysis of Photoacoustic Spectra for the Detection of Short-Chained Hydrocarbon Isotopologues

Molecules ◽  
2020 ◽  
Vol 25 (9) ◽  
pp. 2266 ◽  
Author(s):  
Alain Loh ◽  
Marcus Wolff
Keyword(s):  
Multivariate Analysis ◽  
Continuous Wave ◽  
Light Sources ◽  
Least Squares Regression ◽  
Detection Scheme ◽  
Concentration Determination ◽  
Multiple Measurements ◽  
Interband Cascade Lasers ◽  
Cascade Lasers

We report, to our knowledge, the first optical detection scheme for short-chained hydrocarbon isotopologues. The sensor system is based on photoacoustic spectroscopy (PAS). Two continuous wave, thermoelectrically cooled, distributed feedback interband cascade lasers (DFB-ICLs) with emission wavelengths around 3.33 and 3.38 μm, respectively, served as light sources. The investigations comprised the main stable carbon isotopologues of methane (12CH4, 13CH4), ethane (12CH3-12CH3, 13CH3-12CH3, 13CH3-13CH3), and propane (12CH3-12CH2-12CH3, 13CH3-12CH2-12CH3). They were selected because of their importance for numerous applications from climate and planetary research to natural gas exploration. Multiple measurements of single components in nitrogen and synthetic mixtures were conducted at room temperature and atmospheric pressure. Depending on the investigated hydrocarbon isotopologue, detection limits ranging from 0.043 ppmv to 3.4 ppmv were achieved. For a selective concentration determination, multivariate analysis (MVA) was applied. Partial least-squares regression (PLSR) was used to calculate concentrations from the PA spectra. The implementation of MVA has shown that the PA setup in principle works reliably and that the selective concentration determination of short-chained hydrocarbon isotopologues is possible.

Bubble Behaviour in Viscous Flows: Experimental and Numerical Determination of 3D-Trajectories

2006 ◽  
Author(s):  
Sylvain Chaminade ◽  
Jean Toutain ◽  
Stefan Dilhaire ◽  
Eric Arquis ◽  
Christine Marraud ◽  
...  
Keyword(s):  
Viscous Flows ◽  
Coupling Model ◽  
Light Sources ◽  
Visualization Method ◽  
Air Bubble ◽  
Video Cameras ◽  
Silicon Oil ◽  
Selection Of ◽  
Bubble Behaviour

We studied the air bubble behavhiour in viscous flows. A one-way coupling model was developed, based on lagrangian method. In order to validate this model, experiments were carried out. Our experimental installation was based on shadow visualization method. Bubbles were introduced in a transparent Plexiglas tank filling with viscous fluid (e.g. silicon oil) and were illuminated by diffused lights. In order to reconstruct 3D-trajectories, two video cameras, orthogonally placed, took pictures of shape bubbles and a post treatment of images acquired allowed us to determine the position of the center and the radius of each bubble. Thus, from this information of each plane, we could determine the 3D parameters of bubbles. Superluminescent LEDs with different wave-lengths were used as light sources. The choice of the wavelengths for each plane illumination and the selection of appropriated RGB filter of CCD sensor allowed us to prevent dissymmetry of bubble shape which was due to parasitic orthogonal illumination. Numerical results agree with experimental data.

Study on Organic Triplet Exciton Emission and Quenching Processes by Low-temperature Photo- and Electroluminescence Spectroscopy

2008 ◽  
Vol 1115 ◽  
Author(s):  
Nils Asmus Kristian Kaufmann ◽  
Frank Jessen ◽  
M. Heuken ◽  
Herbert Boerner ◽  
Holger Kalisch ◽  
...  
Keyword(s):  
Low Temperature ◽  
Charge Carrier ◽  
Carrier Density ◽  
Organic Materials ◽  
Energy Levels ◽  
Triplet Exciton ◽  
Light Sources ◽  
Charge Carrier Density ◽  
Electrical Excitation

AbstractOrganic light emitting diodes (OLED) are efficient light sources based on organic semiconductors. Unlike inorganic LEDs which are more or less point sources, OLED are planar light sources with up to 1 m2 in area. By using organic materials, they are cheap to produce and economical to use. The determination of triplet exciton energy levels is of interest for the development of efficient OLED, based on the fact that electrical excitation usually creates three times as many triplets as singlets. Additionally, the knowledge of these energy levels is crucial for the design and choice of emitter matrix materials and exciton blocking layers. These values are normally determined by photoluminescence (PL) measurements in solution for materials which show intersystem crossing (ISC) between singlet and triplet states. For some materials, the triplet levels cannot be measured this way because some materials prohibit ISC. In this work, a method is presented which allows the determination of the energy levels using low-temperature electroluminescence (EL) spectroscopy. The dependence on ISC is avoided by creating triplets directly with electrical excitation and this allows to measure a large class of organic materials. A low-temperature EL spectrum is presented for N,N'-bis(3-methylphenyl)-N,N'-diphenyl-[1,1'-biphenyl]-4,4'-diamine (TPD) in a 3-phenyl-4-(1‘-naphthyl)-5-phenyl-1,2,4-triazole (TAZ) matrix (TPD/TAZ 1:3) at 77 K. Triplet emission is only observed at very low charge carrier density (0.5 μA/mm2). Quenching processes are analyzed using combined EL and PL measurements and unipolar devices. Two factors can be the cause of the quenching: A strong quenching based on a low concentration of electrically activated impurities could explain the dependency. The other explanation points to a quenching based on electrons in the emitting layer. This might be explained with triplet-polaron quenching (TPQ). TPQ is proportional to the charge carrier density and contributes the dominant part to the quenching at low current densities.

Simple spectrophotometric determination of sulfate free radicals

2018 ◽  
Vol 10 (28) ◽  
pp. 3470-3474 ◽  
Author(s):  
Chen Wang ◽  
Rui Chen ◽  
Ruyu Zhang ◽  
Naidong Zhang
Keyword(s):  
Free Radicals ◽  
Spectrophotometric Determination ◽  
Sulfate Radical ◽  
Light Sources ◽  
Sulfate Radicals ◽  
Simple Method

A rapid and simple method for sulfate radical determination was described and the generation rates of sulfate radicals generated by photolysis of persulfate under different light sources were studied.

scholarly journals Nonlinear Spatial Localized Strain Waves

2018 ◽  
Vol 183 ◽  
pp. 02030
Author(s):  
Vladimir I. Erofeev ◽  
Sergey I. Gerasimov ◽  
Alexey O. Malkhanov
Keyword(s):  
Equations Of State ◽  
Numerical Models ◽  
Hydrodynamic Instability ◽  
Light Sources ◽  
Third Order ◽  
Simultaneous Excitation ◽  
Wave Guides ◽  
Determination Of Parameters ◽  
The Waves

A possible way of study of single waves in solids is discussed. The soliton is one of these waves without shape and parameters varying. Soliton deformation parameters are connected with the elastic moduli of the third order that allows defining values of these moduli by means of the measured solitondeformation parameters in various type waveguides made of the same material. The conditions under which a soliton can exist in a rod are analytically determined. For simultaneous excitation of loading in several wave guides two new energetic photosensitive structures (the mixtures are given) initiated by means of short light impulses of noncoherent light sources are proposed. Conditions of excitation of the waves on the basis of multipoint optical initiation loading impulses are described. As a technique for registration the shadowgraph visualization is proposed. It is discussed, how the problem connected to the use of energetic initiation structures consisting in the power background illumination can be solved. The shadow scheme with the use of a tiny dot explosive light source (Tbr ~41 kK) allows to carry out modelling experiments on research of slabbing actions, jet formations, fluffings, hydrodynamic instability during shock-wave loading of investigated samples, which makes it attractive for determination of parameters in equations-of-state for investigated materials, creation of numerical models and their validation. Some examples showing basic possibility of application of the declared techniques are included.

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