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Développement de capteurs ultrasonores SAW basés sur des substrats piézoélectriques de type vitrocéramique pour des mesures de pression et d’humidité à haute température
No full textInternational audienc
High-speed integrated silicon germanium optical modulator with 3 GHz bandwidth in the 5-9 µm wavelength range
No full textInternational audienceMid-infrared spectroscopy is a powerful technique for identifying chemical and biological substances, increasing the demand for compact and cost-effective integrated systems. In this context, integrated electro-optic modulators are essential to implement advanced techniques such as synchronous detection or dual-comb spectroscopy. In this paper, we present a waveguide-integrated electro-optic modulator operating in a broad spectral range from 5 to 9 µm wavelength, based on a Schottky diode embedded in a graded silicon germanium waveguide. By using the free-carrier plasma absorption effect, the device achieves an extinction ratio of up to 1.9 dB at a wavelength of 9 µm. Two different methods have been used to evaluate the device speed. In both cases, high-speed operation up to 7 GHz is obtained, while the optical bandwidth is estimated to be around 3 GHz. These results represent a significant step forward in both the development of characterization techniques and in the performance of mid-IR integrated modulators, paving the way for high-performance on-chip spectroscopic systems
PHY/MAC Cross-Layer Design Using NOMA for Next Generation C-V2X
No full textInternational audienceAs vehicle-to-everything (V2X) communication becomes essential for autonomous and connected vehicle ecosystems, enhancing performance through advanced multiple access techniques is increasingly vital. This paper introduces a novel cross-layer design integrating non-orthogonal multiple access (NOMA) in the physical (PHY) and medium access control (MAC) layers of cellular V2X (C-V2X) systems, with a focus on improving system throughput, reliability, and resource efficiency. Through analytical modeling and simulation, we evaluate the impact of NOMA-based resource allocation and user pairing strategies compared to traditional orthogonal multiple access (OMA) methods. Simulation results confirm that NOMA significantly boosts throughput and spectral efficiency, particularly in low-to-moderate user densities; however, as the number of users rises beyond 10, interference among far users and the complexity of successive interference cancellation (SIC) for near users present performance trade-offs in packet error rate (PER) and throughput. These findings highlight the need for advanced power allocation, interference management, and hybrid solutions to sustain NOMA's advantages in dense vehicular environments.</div
Analysis of a one dimensional energy dissipating free boundary model with nonlinear boundary conditions. Existence of weak solutions
No full textThis work is part of a general study on the long-term safety of the geological repository of nuclear wastes. A diffusion equation with a moving free boundary in one dimension is introduced and studied. The model describes some mechanisms involved in corrosion processes at the surface of carbon steel canisters in contact with a claystone formation. The main objective of the paper is to prove the existence of weak solutions to the problem which are maximal in time. For this, a time semidiscrete minimizing movements scheme based on a Wasserstein-like distance is introduced. The existence of solutions to the scheme is proved. Then, using a priori estimates, it is shown that as the time step goes to zero these solutions converge up to extraction towards a maximal weak solution to the free boundary model
Digital Libraries and Archives. Analysing les Carnots (1780s'–1824), Newton Principia Geneva Edition ([1739–1742] 1822) and Galiani's Manuscripts Osservazioni on Principia (1700-1708): Sources, Texts, Translation, Commentaries. In: Commission on Bibliography, Archive and Records Symposium
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Preface to 'Newton, Principia, Newton Geneva Edition (17th –19th) and Modern Newtonian Mechanics: Heritage, Past-and–Present' Theme Issue
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Projet ImaginIRL : export de la base Omeka S
No full texthttps://meshs-omekas.univ-lille.fr/omeka-s/s/imaginirl/page/accuei
