Search results for "electronics"

Effect of irradiation temperature on the radiation induced attenuation of Ge-doped fibers

2016

International audience; The UV-visible radiation induced attenuation (RIA) was studied in Ge-doped optical fibers, during X-ray (10 keV) irradiations at different temperatures. By comparing the spectra recorded in dissimilarly irradiated samples we evidenced the impact of the irradiation temperature. In details, we highlighted that, from a certain dose, increasing the temperature the RIA decreases for wavelengths lower than 470 nm, whereas at higher wavelengths the RIA depends only on the dose. Such findings suggest that it is possible to distinguish the irradiation temperature by comparing the signal at two different wavelengths. From the microscopic point of view, it appears that the RIA …

Surface Acoustic Waves Propagation at Lossy Metasurfaces: Experimental and Theoretical Characterization of Complex Dispersion Relations

2016

International audience; While metasurfaces properties are known to govern the dispersion relation of Surface Acoustic Wave (SAW) that mimics surface plasmon phenomena, little attention has been paid to the effects of micro-structural dissipation on that dispersion relation. Here we report the experimental and theoretical characterization of both SAW propagation and attenuation in the presence of a lossy metasurface. The latter consists of quarter-wavelength resonators embedded in a rigid board and arranged periodically in a square lattice. Complex SAW wavenumbers are retrieved experimentally using a spatial Laplace Transform, and experimental results are compared with those from an analytic…

Convergences des logiques sociales de la collaboration et des communautés en ligne

2012

How to create and / or control a group online, in or outside the boundaries of the organization so that it contributes to economic development of the company? This question functionalist concerns us, as sociologists and researchers in CIS, the hypothetical convergence of marketing and managerial logics in building community online. Fruits of political knowledge management, management of the symbolic and innovation processes in the organization in part, and an effective marketing strategy of intermediation between the user / consumer / innovator and consumer product for another part, the convergent approach and instrumental group online is sure to redefine the contours of the process of soci…

Oblique angle co-deposition of nanocolumnar tungsten thin films with two W sources: Effect of pressure and target current

2022

Two series of tungsten thin films are sputtered on silicon and glass substrates by oblique angle co-deposition technique with an original configuration. Two opposite distinct tungsten targets are simultaneously used, both tilted with an oblique angle of 80°. The growth is performed at low (0.33 Pa) and high (1.5 Pa) argon sputtering pressure and the current intensity applied to the targets varies between 50 and 250 mA. The effect of these deposition parameters on the films microstructure and electrical properties is investigated by scanning and transmission electron microscopy, X-ray diffraction and pole figures, and van der Pauw method. Due to self-shadowing effect, all tungsten sputtered …

Multicriteria optimization of 3D printed wing using PLA reinforced with carbon fiber

2021

The purpose of this work is the optimal conception of a wing built using fused deposition modeling (FDM),<br&gtwhich is one of the main additive manufacturing (AM) process. PLA reinforced with carbon fiber was selected for the<br&gtfilament as we have defined their mechanical properties in previous work. The optimization approach use hybrid strategy<br&gtbased on surface response method with kriging model and a heuristic method to avoid to be trapped in local<br&gtminimization/maximization. The objective functions for this optimization are the weight, the drag (functions to minimize)<br&gtand the lift (function to maximize) with respect to the failure criteria of the composite material used…

Ballistic and thermalized regimes to tune structure and conducting properties of W-Mo thin films

2022

Detection of Indoor Air Pollutants Using Reactive Sputtering/GLAD of Tin Oxide Thin Films

2021

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Guidance of surface elastic waves along a linear chain of pillars

2016

International audience; The propagation of surface elastic waves, or surface phonons, is considered along a linear and periodic chain of cylindrical pillars sitting on a semi-infinite solid substrate. A variety of guided modes, some of them exhibiting a very low group velocity, are shown to exist at frequencies close to the resonance frequencies of the pillars. Although the pillar diameter is typically smaller than half the relevant wavelength, lateral radiation on the surface is found to be canceled. Surface guidance is explained by the hybridization of the resonating pillars with the continuum of elastic waves of the substrate.

Guiding and confinement of interface acoustic waves in solid-fluid pillar-based phononic crystals

2016

International audience; Pillar-based phononic crystals exhibit some unique wave phenomena due to the interaction between surface acoustic modes of the substrate and local resonances supported by pillars. In this paper, we extend the investigations by taking into account the presence of a liquid medium. We particularly demonstrate that local resonances dramatically decrease the phase velocity of Scholte-Stoneley wave, which leads to a slow wave at the solid/fluid interface. Moreover, we show that increasing the height of pillars introduces a new set of branches of interface modes and drastically affects the acoustic energy localization. Indeed, while some modes display a highly confined pres…

Specificity and Sensitivity Characterization of a Gallium Arsenide Resonant Bio-Sensor

2018

International audience; The characterization of the performances of a Gallium Arsenide (GaAs) based biosensor, in terms of sensitivity and specificity, is reported. The design of the sensor consists in a resonant membrane fabricated in GaAs crystal that operates at shear modes of bulk acoustic waves generated by lateral field excitation. The transducer element was fabricated by using typical clean room microfabrication techniques. The backside of the membrane is functionalized by a self-assembled monolayer (SAM) of alkanethiols to immobilize bio-receptors, which will allow the specific capture of the analyte of interest. The theoretical sensitivity of the sensor had been determined by model…