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Biomechanical finite element simulation of the pelvic organs under dynamic loading and validation against experimental data from magnetic resonance imaging
No full textInternational audienc
Critical points of solutions of elliptic equations in divergence form in planar non simply connected domains with smooth or nonsmooth boundary
No full textWe study the critical points of the solution of second elliptic equations in divergence and diagonal form with a bounded and positive definite coefficient, under the assumption that the statement of the Hopf lemma holds (sign assumptions on its normal derivatives) along the boundary. The proof combines the argument principle introduced in [4] for elliptic equations with the representation formula (using quasi-conformal mappings) for operators in divergence form in simply connected domains [5]. The case of a degenerate coefficient is also treated where we combine the level lines technique and the maximum principle with the argument principle. Finally, some numerical experiments on illustrative examples are presented
Le contentieux de l'abattage d'arbres d'alignement. L'exemple rennais.
No full textInternational audienc
Ultrasound-actuated microfluidic flow focusing allows control of bubble size and production rate
No full textInternational audienceMicrofluidic flow focusing is a promising tool for the creation of monodisperse microbubbles, such as ultrasound contrast agents. However, industrial-scale bubble production remains elusive due to a lack of control over bubble size and production rate in devices with paralellized flow-focusing nozzles. In this paper we introduce a way of fine-tuning the production rate and bubble size through the use of ultrasound excitation. We show that the production rate can be locked to the ultrasound driving frequency and that the bubble size depends on the acoustic driving pressure. These results may be exploited in particular to increase monodispersity in parallelized systems
Emerging vertical GaN-on-Silicon devices for next generation power electronics
No full textInternational audienceAlthough promising and qualified up to 650 V voltage operation, lateral GaN HEMT devices are subject to severe limitations for higher voltage applications such as a large device size, surface trap related reliability concerns or the absence of avalanche breakdown due to the peak electric field at the gate vicinity. This led to vertical GaN development, potentially enabling to overcome all the above-mentioned issues. State-of-the-art vertical GaN devices are fabricated on bulk GaN substrates owing to the reduced dislocation density and low impurity concentrations. However, native GaN substrates are prohibitively expensive, and only available in rather small size.In this talk, we will describe a unique approach and current status of GaN-based fully vertical devices grown on large diameter silicon substrate. Despite the common belief about the limited drift layer thickness or wafer diameter due to the large mismatch in coefficient of thermal expansion (CTE) between Si and GaN, we will show that a local substrate removal with suitable related growth and process optimization enabled outstanding initial achievements such as extremely low on-resistance in 1200 V-class fully vertical pn diodes with avalanche breakdown capability and high on-state current capability
Celebrating 75 Years of the IEEE Circuits and Systems Society Across Europe [CASS Conference Highlights]
No full textInternational audienceIn celebration of the 75th anniversary of the IEEE Circuits and Systems Society (CASS), a series of events were held across Eu-rope from November to December 2024, organized by local CASS chapters in countries including Turkey, France, Switzerland, Fin-land, Italy, Denmark, and the United Kingdom. Each event emphasized collaboration, innovation, and student engagement andcovered topics such as biomedical systems, integrated circuits, codecs, AI and IoT convergence, quantum electronics, and thesemiconductor industry. These gatherings brought together professionals, academics, students, and industry leaders to fosterknowledge exchange. The anniversary tour reinforced the society’s mission across Europe.Index Terms—Circuits and Systems Society, European CASS chapters, academic-industry collaboration in electronics
Stabilization of Nonlinear Systems via Subset-Based Membership Functions and Exact Polytopic Representation
No full textInternational audienceThis letter introduces a novel approach for ensuring the asymptotic stabilization of nonlinear systems by constructing an exact polytopic representation of the system in a region of interest using a trapezoidal partition. Unlike traditional methods, such as gain scheduling or piecewise approximations, the proposed approach does not rely on such approximations and ensures that the derived stabilization conditions are directly applicable to the original nonlinear system. A systematic iterative design algorithm is introduced to compute the control gains, guaranteeing asymptotic stabilization for the nonlinear system. The effectiveness of the proposed approach is demonstrated through numerical examples, highlighting its advantages over traditional methods
Réalisation d’une cellule en verre nanostructurée en HSQ. Infiltration par une vapeur de Césium. Application de physique fondamentale
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Recherche préliminaire pour le développement d'une méthodologie d'évaluation environnementale intégrant les performances mécaniques issues des procédés de fabrication additive métallique
No full textInternational audienceRecherche préliminaire pour le développement d'une méthodologie d'évaluation environnementale intégrant les performances mécaniques issues des procédés de fabrication additive métalliqu