Search results for "Technology"
showing 10 items of 30343 documents
Comparaison expérimentale de techniques de caractérisation en intensité et phase d'impulsions optiques ultracourtes
2006
Nous comparons experimentalement les resultats de la caracterisation en intensite et en phase d'impulsions optiques ultracourtes obtenus par differentes techniques employant un montage auto/inter-correlateur en intensite et un analyseur de spectre. Nous employons pour ces tests une impulsion en limite de Fourier, une impulsion affectee par l'auto-modulation de phase et une impulsion similariton.
A Study of Milk Particles Size Variation with pH Change using Dynamic Light Scattering
2019
A very simple experimental setup for a Dynamic Light Scattering measurement was used to measure the average size of the milk proteins in aqueous suspensions at 20 °C. The PH of the suspensions was adjusted using Calcium lactate, in its most common form of pentahydrate C6H10CaO6•5H2O. The mean size variation of the suspended particles in time has been monitored and reveals a fast increase over a time interval of less than ten of seconds.
Polarization-driven spin precession of mesospheric sodium atoms: publisher's note.
2018
This publisher's note corrects an error in the author listing of Opt. Lett.43, 5825 (2018)OPLEDP0146-959210.1364/OL.43.005825.
Estimation des incertitudes de mesure sur bras polyarticulé portable par méthode de Monte Carlo
2013
International audience; Les bras polyarticulés portables ont progressivement évolué et sont de plus en plus utilisés dans l’industrie. Cependant, à l’heure actuelle, la traçabilité de ces dispositifs est difficile à effectuer et les incertitudes de mesures relatives à l’utilisation de ces appareils ne sont pas quantifiées. Le travail mené consiste à déterminer les incertitudes de mesures associées à la quantification, par un bras polyarticulé portable, des caractéristiques géométriques et dimensionnelles d’une pièce mécanique. Les travaux visant à élaborer un modèle d’incertitude de mesure, sont basés sur la méthode de Monte Carlo du supplément 1 du Guide pour l'expression de l'incertitude …
Effective characterization of the phase and intensity profiles of asymmetrically distorted light pulses in optical fiber systems
2009
International audience; We address the problem of characterization of light pulses that propagate in long-haul high-bit-rate optical communication systems under strongly perturbed conditions. We show that the conventional technique for characterization of the phase and intensity profile of such pulses becomes qualitatively inconsistent when the pulse's profile is asymmetrically distorted with respect to its center of mass. We resolve these inconsistencies by partially reformulating the conventional technique by means of appropriate pulse parameters, which we call upgraded parameters, that allow a fair characterization of the intensity and phase of all types of light pulses, including those …
Supercontinuum generation in titanium dioxide waveguides
2019
International audience; Optical supercontinua are a fundamental topic that has stimulated a tremendous practical interest since the early works of Alfano et al. in the 70’s in bulk components. Photonic crystal fibers have then brought some remarkable potentialities in tailoring the dispersive properties of a waveguide while maintaining a high level of confinement over significant propagation distances. The next breakthrough is to further reduce the footprint of the nonlinear component and to achieve the generation of optical supercontinuum on a photonic chip. To reach this aim, several platforms have been successfully investigated such as silicon, silicon germanium, silicon nitride, chalcog…
Climatic conditions influence emerging mycotoxin presence in wheat grown in Romania – A 2-year survey
2017
Abstract The correlation between the occurrence of four enniatins (ENA, ENA1, ENB, and ENB1) and beauvericin (BEA) and the weather parameters during anthesis and preharvest period was studied in 97 wheat samples collected in 2014 and 2015 across three counties from central and south Romania (Brasov, Dâmboviţa, and Teleorman). The highest mean values of ENA (16.1 μg kg −1 ) and ENB (147.1 μg kg −1 ) were measured in the samples from Brasov county in the harvest year 2015, whereas for ENA1 and ENB1 the highest means (55.2 μg kg −1 , and 108.0 μg kg −1 , respectively) were noted in samples from Teleorman county in 2014. Statistically significant differences ( P r s = 0.8745 and r s = 0.9326;…
Les enjeux de la sécurité des objets connectés et applications de santé
2016
International audience; The challenges of security of connected objects and health applicationsThe market for connected objects and health applications is booming and is expected to be several billion euros in revenue in the coming years. Their development will have a similar impact to what we experienced with the development of internet earlier this century but even more it should disrupt the organization of our health system, profoundly change the management of care and revolutionize prevention, but it could also call into question medical confidentiality and protection of personal data. This article analyses the societal implications of OCS, the need for a dual medical and ethical evalua…
2,4,5-Triaryl imidazole probes for the selective chromo-fluorogenic detection of Cu(II). Prospective use of the Cu(II) complexes for the optical reco…
2019
The sensing behaviour toward metal cations and biothiols of two 2,4,5-triarylimidazole probes (3a and 3b) is tested in acetonitrile and in acetonitrile-water. In acetonitrile the two probes present charge-transfer absorption bands in the 320-350 nm interval. Among all cations tested only Cu(11) is able to induce bathochromic shifts of the absorption band in the two probes, which is reflected in marked colour changes. Colour modulations are ascribed to the formation of 1:1 Cu(II)-probe complexes in which the cation interacts with the imidazole acceptor heterocycle. Besides, the two probes present intense emission bands (at 404 and 437 nm for 3a and 3b respectively) in acetonitrile that are q…
9,10-Phenanthrenedione as Visible-Light Photoredox Catalyst: A Green Methodology for the Functionalization of 3,4-Dihydro-1,4-Benzoxazin-2- Ones thro…
2018
A visible-light photoredox functionalization of 3,4-dihydro-1,4-benzoxazin-2-ones through a Friedel-Crafts reaction with indoles using an inexpensive organophotoredox catalyst is described. The reaction uses a dual catalytic system that is formed by a photocatalyst simple and cheap, 9,10-phenanthrenedione, and a Lewis acid, Zn(OTf)2. 5W white LEDs are used as visible-light source and oxygen from air as a terminal oxidant, obtaining the corresponding products with good yields. The reaction can be extended to other electron-rich arenes. Our methodology represents one of the most valuable and sustainable approach for the functionalization of 3,4-dihydro-1,4-benzoxazin-2-ones, as compared to th…