Search results for "ACOUSTIC"
showing 10 items of 1590 documents
Terpyridine-based metallopolymer thin films as active layer in ammonia sensor device
2016
International audience; A metal-containing polymer has been prepared by electropolymerization of an homoleptic Ru(II)-terpyridine complex bearing pyrrole heterocycles. The polymer is obtained as a thinfilm at the surface ofelectrodes, and has been characterized by electrochemical measurements, XPS and microscopy. It hasbeen shown that this polymer acts as an active gas sensitive layer since it enables the detection of anammonia gasflow through layer’s resistivity measurements.
Comparaison entre PESQ et MUSHRA pour l’estimation de la qualité audio d’un signal de parole enregistré par des microphones « non-conventionnels »
2022
Lorsque l'on parle, on génère non seulement du signal aérien, mais aussi des vibrations qui se propagent dans les différents éléments constituant notre tête. Ces vibrations contiennent l’information du signal de parole et peuvent être enregistrées. On appelle microphones « non conventionnels » tous les capteurs permettant d’enregistrer ces signaux se propageant dans notre corps. Les microphones non conventionnels sont souvent moins sensibles au bruit ambiant que les microphones acoustiques classiques, ils peuvent être utilisés dans des environnements difficiles et ils sont compatibles avec les équipements de tête tels que les masques de protection NRBC. Le plus ancien microphone « non conve…
PubPrivLands, une étude des effets combinés du bruit, de la pollution de l’air et des espaces verts en milieu urbain
2022
Les espaces verts urbains procurent une multitude de services écosystémiques. Les bénéfices pour la population sont de mieux en mieux connus, en particulier sur les aspects de bien-être, de pratique d’activité physique, de statut pondéral, et également de prévention des maladies cardiovasculaires. Cependant, en milieu urbain, d’autres expositions environnementales, notamment le bruit et la pollution de l’air, sont présentes et influencent le statut sanitaire de la population urbaine. La part relative des bénéfices liés aux espaces verts (proximité, accessibilité…) et des effets délétères en lien avec le bruit et la pollution de l’air reste à ce jour mal connue. L’objectif de l’étude est d’a…
Altérations des formants par l’utilisation de microphones « non conventionnels »
2022
Dans les environnements bruyants la communication à distance est un véritable défi. L’utilisation de microphones classiques enregistrant l’onde aérienne émise par la bouche et les narines peut poser problème tant sur le plan de l’ergonomie que sur celui de la robustesse dans l’acquisition du signal de parole. Les microphones non conventionnels (laryngophones, microphones à conduction osseuse, microphones intra-auriculaires …) qui mesurent le signal de parole se propageant au travers du corps, apportent une nouvelle solution. En effet, ils sont moins sensibles aux bruits environnants et sont compatibles avec des équipements de tête comme les masques à gaz. Cependant l’intelligibilité et la q…
On the analytical expression of the multicompacton and some exact compact solutions of a nonlinear diffusive Burgers’type equation
2018
International audience; We consider the nonlinear diffusive Burgers' equation as a model equation for signals propagation on the nonlinear electrical transmission line with intersite nonlinearities. By applying the extend sine-cosine method and using an appropriate modification of the Double-Exp function method, we successfully derived on one hand the exact analytical solutions of two types of solitary waves with strictly finite extension or compact support: kinks and pulses, and on the other hand the exact solution for two interacting pulse solitary waves with compact support. These analytical results indicate that the speed of the pulse compactons doesn't depends explicitly on the pulse a…
Generation of a 160-GHz transform-limited pedestal-free pulse train through multiwave mixing compression of a dual-frequency beat signal.
2002
International audience; We report the experimental generation of a 160-GHz picosecond pulse train at 1550 nm, using multiple four-wave mixing temporal compression of an initial dual-frequency beat signal in the anomalous-dispersion regime of a nonzero dispersion-shifted fiber. Complete intensity and phase characterizations of the pulse train were carried out by means of a frequency-resolved optical gating technique, showing that 1.27-ps transform-limited pedestal-free Gaussian pulses were generated.
Fabrication et usinage des guides en verre de tellurite pour l'optique non-linéaire intégrée
2021
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Design rules for nonlinear spectral compression in optical fibers
2016
International audience; We present comprehensive design rules to optimize the process of spectral compression arising from nonlinear pulse propagation in an optical fiber. Extensive numerical simulations are used to predict the performance characteristics of the process as well as to identify the optimal operational conditions within the space of system parameters. It is shown that the group-velocity dispersion of the fiber is not detrimental and, in fact, helps achieve optimum compression. We also demonstrate that near-transform-limited rectangular and parabolic pulses can be generated in the region of optimum compression.
Nonlinear sculpturing of optical pulses with normally dispersive fiber-based devices
2018
International audience; We present a general method to determine the parameters of nonlinear pulse shaping systems based on pulse propagation in a normally dispersive fiber that are required to achieve the generation of pulses with various specified temporal properties. The nonlinear shaping process is reduced to a numerical optimization problem over a three-dimensional space, where the intersections of different surfaces provide the means to quickly identify the sets of parameters of interest. We also show that the implementation of a machine-learning strategy can efficiently address the multi-parameter optimization problem being studied.
The 2014 Magnetism Roadmap
2014
Magnetism is a very fascinating and dynamic field. Especially in the last 30 years it has experienced many major advances in the full range from novel fundamental phenomena to new products. Applications such as hard disk drives and magnetic sensors are part of our daily life, and new applications, such as in non-volatile computer random access memory, are expected to surface shortly. Thus it is timely for describing the current status, and current and future challenges in the form of a Roadmap article. This 2014 Magnetism Roadmap provides a view on several selected, currently very active innovative developments. It consists of 12 sections, each written by an expert in the field and addressi…