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Le rôle des polymères dans les batteries tout-solide et leur mise à l'échelle
No full textThe imperative transition toward renewable energy sources and the ongoing electrification of transportation position battery technologies at the forefront of this transformation. While the lithium-ion technology is already well-established, the quest for higher energy density has drawn significant attention to the emerging solid-state batteries (SSBs). Their working principle is based on ion and electron transfers through solid-solid contacts, which are complex to master and sustain, giving rise to most of the challenges associated with their realisation. Especially, the capability to scale up SSBs' fabrication process is critical for future implementation and calls for a shift from pellet-type to sheet-type assembly. Thus, this doctoral research delved into the role of polymers in facilitating this transition by exploring two strategies differing on the binder's ability to conduct lithium ions. In the first approach, we capitalised on the polymer electrolyte PEO:LiTFSI favourable mechanical properties to prepare self-standing films of hybrid solid electrolyte with a high content of Li6PS5Cl, using a dry process. However, the instability between the organic and inorganic phases resulted in a resistive interphase that prevents a shared conduction mechanism within the hybrid. After that, we pursued a simpler approach to fabricate self-standing SSBs by employing a conventional non-conductive binder, PVDF-HFP, and using a slurry-based tape casting process. The thorough optimisation of the formulation and preparation of the electrodes and solid-state separators gave promising results, closely approaching the electrochemical performance of binder-free reference SSBs, even under low operating pressure. The reliability of our fabrication process thus paves the way for assembling self-standing solid-state full cells, integrating high energy density anodes such as lithium metal.Dans un contexte de transition vers les énergies renouvelables et d'électrification de la mobilité, les batteries sont un rouage indispensable à cette transformation. Alors que la technologie lithium-ion est aujourd'hui largement établie, la course à la performance en matière de densité d'énergie mise sur les batteries tout-solide, encore à l'état de prototype. Elles sont basées sur le principe du transfert de charge au travers de contacts purement solides, complexes à former et à maintenir, et donc sources de nombreux problèmes associés à leur fonctionnement. La mise à l'échelle des procédés de fabrication des batteries tout-solide est particulièrement critique et nécessite un changement de stratégie d'assemblage, en abandonnant le format en pastille pour tendre vers un montage en feuillets. Dans ce contexte, nos travaux de recherche ont porté sur le rôle des polymères dans l'adaptation du procédé d'assemblage, en tant que liant des particules inorganiques. Nous avons exploré deux stratégies qui se distinguent par rapport à la nature de ce liant, pouvant être conducteur ou non des ions lithium. Dans une première approche, l'électrolyte polymère PEO:LiTFSI a été utilisé pour préparer des films autosupportés d'électrolyte hybride à haut taux de charges inorganiques Li6PS5Cl, suivant un procédé à sec. L'instabilité des deux électrolytes en contact génère cependant une interphase trop résistive pour assurer une conduction ionique conjointe au sein de l'hybride. Dans un souci de simplification du système, une nouvelle approche a été adoptée, se basant sur un liant non conducteur, le PVDF-HFP, pour la préparation et le coulage en bande d'une encre afin d'obtenir des films d'électrodes et de séparateurs. Une optimisation minutieuse des paramètres a permis d'obtenir des résultats encourageants puisque que proches du système de référence ne contenant pas de liant, et ce même à basse pression de cyclage. La fiabilité du procédé développé au cours de cette thèse ouvre maintenant la voie vers l'assemblage de cellules tout-solide complètes, intégrant une anode à haute densité d'énergie telle que le lithium métal
Downregulation of V-ATPase V(0) Sector Induces Microvillus Atrophy Independently of Apical Trafficking in the Mammalian Intestine
No full textInternational audienc
Omenology as choreography: remarks on the ritual nature of political action in response to eclipses in early imperial China
No full textInternational audienceWell before the first empire (221–206 B.C.), the Chinese practised a form of uranomancy, or portent astrology, so similar to what we find in Mesopotamia as to invite conjecture about their common origins. The metaphysical basis is, in short, that as the world came into being through mitosis from a state of singularity, the ‘ten thousand things’ on earth saw themselves reflected in the myriad forms among the stars, the strands of destiny connecting them and projecting, through sympathy, terrestrial disturbances upon the sky. Due to its modern classification as a ‘pseudo-science’, twentieth-century scholarship on the subject tended to focus on fakery: on political manipulations and historical fabrications. It is only in the last decade, most notably in the work of Chen Kanli, that we have begun to shift our attention to the ways in which this science was earnestly developed and integrated into classical scholarship, ethics, and ritual at the imperial court. Building upon this, I will present the results of a statistical study of imperial decrees issued in response to solar eclipses from A.D. 25 to 581. Examined en masse, we will see that that throne’s historical words and actions are formulaic and concerned principally with virtue, lending themselves to comparison with the classical drum ceremony held to drive away the eclipse. In other words, setting aside the questions of scepticism and belief, I suggest that we think of omens, in early imperial China, as occasions for ritual action to reinforce ethical norms
Onset of collectivity for argon isotopes close to N=32
No full textInternational audienceThe shell closure at N=32 has been investigated by a first spectroscopy of the N=31 nucleus Ar49 at the Radioactive Isotope Beam Factory. Using the Ar50(p,pn) reaction channel in inverse kinematics, Ar50 projectiles at 217 MeV/nucleon impinged on a 150 mm long liquid hydrogen target, part of the MINOS device. Prompt deexcitation γ rays were measured with the NaI(Tl) array DALI2+. Reaction products were analyzed with the SAMURAI spectrometer, which allowed the measurement of the momentum distributions and angular momentum transfer. Data were compared to state-of-the-art theoretical predictions, including shell-model, energy-density functional, and ab initio calculations. An onset of collectivity is suggested besides the spherical configuration typical of a closed shell nucleus, such as for Ca52
Une symphonie des pouvoirs judiciaires à Byzance: Le rôle de l'Église dans l'administration de la justice (Xe-XVe siècle)
No full textInternational audienceL’Église prend-elle le contrôle de l’administration de la justice à Byzance en obtenant des compétences nouvelles ? Quelles sont les affaires réellement jugées par les tribunaux ecclésiastiques ? Pourquoi le laïc byzantin a-t-il recours à eux ? Tout en donnant un aperçu des litiges quotidiens des Byzantins comme des affaires d’État les plus graves, cet ouvrage permet de mieux caractériser la relation entre le droit écrit byzantin et son application dans les tribunaux. Il met en lumière le rôle actif des clercs dans la résolution des conflits à Byzance dans les tribunaux impériaux et dans leurs activités notariales et arbitrales. Enfin, il s’intéresse aussi à l’indépendance des juges ecclésiastiques vis-à-vis de l’empereur. Romain Goudjil montre ainsi que, loin d’être un juge suprême pour tous les Byzantins, l’Église ne cherche jamais à prendre le contrôle de l’administration judiciaire byzantine. Elle joue le rôle qui lui est attribué en droit et sert les intérêts de l’empereur
Memory-based modes of presentation
No full textInternational audienceTo deal with memory-based modes of presentation I propose a couple of revisions to the standard criterion of difference for modes of presentation attributed to Frege. First, we need to broaden the scope of the criterion so that not merely the thoughts of a given subject at a given time may or may not involve the same way of thinking of some object, but also the thoughts of a subject at different times. Second, we need to ‘relativize’ the criterion of difference to particular subjects in particular situations. Thanks to these revisions, we can make sense of Evans’ notion of a dynamic mode of presentation that persists through time despite lower-level changes. A dynamic mode of presentation is a complex mode of presentation involving several epistemically rewarding relations to the reference successively (in contrast to composite modes of presentation, which involve several epistemically rewarding relations simultaneously). I show how this idea can be cashed out in the mental file framework, and how, in that framework, we can provide a straightforward answer to the question: when is a mode of presentation based on a memory M the same as the mode of presentation based on the perception P from which the memory derives? The answer appeals to the distinction between anchored and unanchored memories
Retinal damage promotes mitochondrial transfer in the visual system of a mouse model of Leber hereditary optic neuropathy
No full textInternational audienceLenadogene nolparvovec is a gene therapy which has been developed to treat Leber hereditary optic neuropathy (LHON) caused by a point mutation in the mitochondrial NADH dehydrogenase 4 (ND4) gene. Clinical trials have demonstrated a significant improvement of visual acuity up to 5 years after treatment by lenadogene nolparvovec but, surprisingly, unilateral treatment resulted in bilateral improvement of vision. This contralateral effect – similarly observed with other gene therapy products in development for MT-ND4-LHON – is supported by the migration of viral vector genomes and their transcripts to the contralateral eye, as reported in animals, and post-mortem samples from two patients. In this study, we used an AAV2 encoding fluorescent proteins targeting mitochondria to investigate whether these organelles themselves could transfer from the treated eye to the fellow one. We found that mitochondria travel along the visual system (optic chiasm and primary visual cortex) and reach the contralateral eye (optic nerve and retina) in physiological conditions. We also observed that, in a rotenone-induced model of retinal damage mimicking LHON, mitochondrial transfer from the healthy to the damaged eye was accelerated and enhanced. Our results thus provide a further explanation for the contralateral beneficial effect observed during clinical studies with lenadogene nolparvovec