The market introduction of high temperature wide bandgap power semiconductor devices with junction temperature exceeding 200°C significantly accelerates the trend towards high power density and severe ambient temperature electronics applications. Such evolution may have a great impact in aeronautics applications, especially with the development of More Electric Aircraft (MEA), since it can allow to reduce the mass and volume of power electronics systems. As a consequence, the aircraft operating cost can decrease. However, for electronics used under such harsh conditions, the package reliability and the heat evacuation are very critical issues. The goal of this project is to design and fabricate high performance double sided cooled power electronics modules with optimized thermomechanical properties. The assembly is based on copper joints and a copper heat sink and integrates several technological breakthroughs. Three main technological bricks will be deeply addressed in order to reach the target: 1) Synthesis of nanoporous copper films, either freestanding or directly deposited on metallized substrates with controlled microstructure: In order to limit the risks, three independent strategies will be investigated during the project: the synthesis of nanoporous copper free standing films using melt-spinning and chemical dealloying techniques, the direct on-substrate electroforming of copper-alloy followed by anodic dealloying, and the direct growth of nanoporous structures without any additional treatment by tuning electrolyte formulation and plating parameters. 2) Thermocompression of the nanoporous copper films for die attach: Conventional heating will be achieved at low pressure and in inert/reductive atmosphere. An alternative method based on laser induced fast heating will also be evaluated to thermocompress the nanoporous copper in air. Both solutions allow to limit the oxidation copper issues. The underlying physical mechanisms taking place during the thermocompression of the various morphologies and microstructures of nanoporous copper films will be in-depth investigated. The joint stability under electro-thermo-mechanical aging conditions will be evaluated. 3) Deposition of thick copper layers for substrate/heatsink assembly using electroforming process: A thick dense metal layer will be deposited on a designed sacrificial polymer preform allowing to create a wide range of complex shapes directly on the metallized substrate with low residual stresses. This technology combined to virtual prototyping will allow us to fabricate high performance heat sink patterns (liquid forced convection without phase change) in terms of high local heat transfer coefficient and low pressure drop. The thermal-hydraulic performances of the heat sinks will be analyzed with an experimental setup. The robustness of the assembly (substrate/heat-sink) under repetitive temperature variations will be also evaluated. Silicon Carbide (SiC) devices based power modules (inverter phase leg) using the aforementioned technological bricks will be realized and evaluated in the project. Electrical, thermal and robustness tests are planned to estimate the module performances. The COPPERPACK project will contribute to validate and push our concept from Technology Readiness Level (TRL) 2 up to a TRL 3-4 with a functional technological demonstrator.

The context of wide bandgap power semiconductor devices necessitates to reinvent current packaging technologies. An innovative solution, based on the integration of power components within heat sinks, seems to be an excellent candidate to increase the power density of static converters. It is also highly modular, which makes it possible to envisage easier design and maintenance. In the DESTINI project, research works will be proposed to set up electrostatic, electrothermal and electromagnetic modeling methods of this kind of package. Reliability aspects will be addressed through the implementation of tools and methods for the study of damage. Technological works will be carried out to make test setups.

Oceanic convection remains poorly understood even though it is one of the main driver of the oceanic dynamics. Convection can be penetrative (entrain water from below the mixed layer) or non-penetrative. While it is reasonably straightforward to formulate conceptual parameterizations of non penetrative convection in idealized settings, it remains challenging to extend the formalism to realistic settings of penetrative convection even for state of the art ocean models. In fact the most advanced parameterization schemes for oceanic convection are still calibrated based on atmospheric data. Moreover these parameterizations do not take into account the rotation of the earth which can substantially impact the individual and collective behavior of convective plumes. The first objective of this proposal is to build an observational database of convective events on the Coriolis Platform (the largest rotating tank of the world). We will complement this dataset with numerical simulations to explore many types of surface forcing and initial conditions. We will then combine these observations and model outputs with a robust theoretical framework to build a consistent parameterization of oceanic convection. Then, we will overcome the constraints of the mathematical framework of existing parameterizations and propose a data-driven approach to formulate a more generic parameterization. Last, we will test these parameterizations in coarse resolution ocean models. We will perform a sensitivity analysis of the oceanic heat uptake as a function of the free parameters to asses how and where our parameterizations can reduce uncertainty of climate projections.

The cochlear implant (CI) in congenital deaf children is now widely considered as a highly efficient means to restore auditory functions. However, after several decades of retrospective analysis, it is clear that there is a large range of recuperation levels, and in extreme cases some CI recipients never develop adequate oral language skills. The major goal of HearCog to improve rehabilitation strategies in CI children, it is to better understand and circumscribe the origins of such variability in CI outcomes. The originality of HearCog project is to consider CI outcomes in a broad range of interdependent aspects, from speech perception to speech production and the associated cognitive mechanism embedded in executive functions. The novelty of the proposal is both theoretical and methodological. The goals will be first to evaluate the capacities of the visual and auditory system to respond to natural environmental stimuli and to analyse neuronal mechanisms induced by sensory loss and recovery through the CI using brain imaging techniques (Functional Near-Infrared Spectroscopy, fNIRS). In view of the co-structuration of speech perception and production during development, we will assess how deafness and CI recovery can alter speech production. But congenital deafness has deleterious impacts that extend beyond the auditory functions and encompass cognitive systems including higher-order executive processes. Based on the disconnecting model (Kral et al., 2016), our objective will be to relate neuronal assessment, using the fNIRS technique, of executive functions to auditory restoration in CI children. HearCog is based on longitudinal assessment on CI infants and age-matched controls, to search for prognosis factors of auditory restoration. We will also compare these measurements to data acquired in older CI children implanted for several years, and controls. In fine our goal is to acquire objective measures of brain reorganization that could be linked to variability in CI outcomes and therefore would constitute a predictive factor. HearCog is at the crossroad of cognitive neuropsychology, clinical research with a strong opening toward education. Consequently HearCog is translational and multidisciplinary with the unique objective to understand the compensatory mechanisms induced by congenital hearing loss to support both the social insertion as well as the insertion within the school system of cochlear implanted deaf children.

Replication of many viruses occurs in specialized compartments formed during infection and known as viral factories. The physicochemical nature of these factories and the molecular basis of their morphogenesis and organization are poorly understood. The Mononegavirales (MNV) order includes several important human pathogens (Rabies virus -RABV-, Measles Virus -MeV-, Ebola virus…). All these viruses have a single strand RNA genome of negative polarity which is encapsidated by the nucleoprotein (N) to form the ribonucleoprotein that is associated with the RNA dependent RNA polymerase and its cofactor the phosphoprotein (P). RABV factories are the Negri bodies (NBs) which are cytoplasmic inclusions housing the synthesis of viral RNA (mRNAs and genomic RNAs). We have demonstrated that NBs constitute a new category of membrane-less liquid organelles. Liquid organelles are formed by liquid-liquid phase separation (LLPS) and contribute to the cell compartmentalization. They are involved in a wide range of cellular processes. So far, the general principles leading to LLPS are poorly understood. Published experimental data indicate that the liquid nature of viral factories can be generalized to other MNVs. This is a paradigm shift which opens new research horizons in the field of MNV replication and invites us to revisit the interplay between viral factories and the components of the cellular innate immunity. This proposal aims to characterize the morphogenesis, the internal organization, the composition, the dynamics and the functions of RABV and MeV viral factories. It brings together 3 teams: a team of virologists and biochemists specialized in rhabdoviruses, another which develops new methods for cell biology on synchrotron radiation sources and a third one developing state-of-the-art solution state NMR and fluorescence approaches to investigate the dynamics and interactions of highly flexible proteins with a strong focus on negative strand RNA viruses structure. The project has six major objectives: 1) Using super-resolution microscopy and focused ion beam scanning electron microscopy, we will characterize the submicrometer organization of NBs and how it evolves all along the viral cycle. NBs ultrastructure will also be investigated by various methods developed on synchrotron radiation sources (e.g. scanning transmission X-ray microscopy or µ-SAXS coupled to correlative imaging). We will also determine viral proteins structural elements which are required for NBs formation. 2) Using in vitro reconstituted systems and a combination of fluorescence techniques and NMR, we will identify the physicochemical principles underlying the LLPS leading to the formation of the viral factory. 3) As LLPS enriches NBs in specific factors, we will characterize NBs’ proteome using a proximity biotinylation assay and identification of proteins by mass spectrometry. We will also identify RNAs which are NBs’ residents. 4) We will characterize the interplay between NBs and cellular innate immunity. Indeed, the sequestration of viral RNAs in NBs raises the question of their accessibility to pathogen recognition receptors such as RIG-I and MDA5. Alternatively, liquid factories might constitute a signature of viral infection and cells might have evolved a mechanism allowing the sensing of such structures and/or their destabilization. 5) Experimental data suggest that RABV factories might also harbor viral proteins translation. We will investigate where viral mRNAs are translated in infected cells and if they use an unconventional mechanism of translation initiation to escape the translation inhibition induced by innate immunity. 5) At some stage, the RNPs must leave the viral factory to form new virions. We will investigate the molecular bases of the processes by which this happens. Beyond its impact in virology and innate immunity, this project should have an impact in cellular biology by increasing our understanding of liquid organelles assembly.