10 research outputs found
Partial least squares regression as a tool to predict fluoropolymer surface modification by dielectric barrier discharge in a corona process configuration in a nitrogen-organic gaseous precursor environment
A dielectric barrier discharge in a corona process configuration is
used to treat the surface of fluoropolymers in a nitrogenâorganic precursor
environment. The surface chemistry, thickness, and water contact angle of the
deposited coatings are measured and used to build up an output matrix to be
correlated with an input matrix built using electrical parameters of the
discharge, the gas mixture chemical composition, and spectroscopic parameters
measured in both the infrared and ultravioletâvisible emission spectral regions.
A partial least-squares regression (PLSR) model enables determining the most
important plasma parameters to drive the coating physicochemical characteristics. From the PLSR model, it is determined that the plasma electrical
parameters drive the surface modification process, at the expense of other
plasma characteristics such as gas flow, gaseous precursor concentration,
nitrogen vibrational temperature, and the level of gaseous precursor conversion
within the plasma
In-situ regolith seismic velocity measurement at the InSight landing site on Mars
InSight's seismometer package SEIS was placed on the surface of Mars at about 1.2 m distance from the thermal properties instrument HP3 that includes a self-hammering probe. Recording the hammering noise with SEIS provided a unique opportunity to estimate the seismic wave velocities of the shallow regolith at the landing site. However, the value of studying the seismic signals of the hammering was only realised after critical hardware decisions were already taken. Furthermore, the design and nominal operation of both SEIS and HP3 are non-ideal for such high-resolution seismic measurements. Therefore, a series of adaptations had to be implemented to operate the self-hammering probe as a controlled seismic source and SEIS as a high-frequency seismic receiver including the design of a high-precision timing and an innovative high-frequency sampling workflow. By interpreting the first-arriving seismic waves as a P-wave and identifying first-arriving S-waves by polarisation analysis, we determined effective P- and S-wave velocities of vP = 114+43-20 m/s and vS = 60+11-7 m/s, respectively, from around 2,000 hammer stroke recordings. These velocities likely represent bulk estimates for the uppermost several 10's of cm of regolith. An analysis of the P-wave incidence angles provided an independent vP/vS ratio estimate of 1.84+0.89-0.35 that compares well with the traveltime based estimate of 1.92+0.52-0.28. The low seismic velocities are consistent with those observed for low-density unconsolidated sands and are in agreement with estimates obtained by other methods
Symétrie brisée et renforcement de contacts cellulaires
Nous avons Ă©tudiĂ© la croissance de contacts cellulaires asymĂ©triques: les jonctions adhĂ©rentes et les contacts focaux. Nous avons montrĂ© par des expĂ©riences d'imageries, de micromanipulation, et d'altĂ©ration des assemblages cellulaires, que la brisure de symĂ©trie des jonctions adhĂ©rentes entre des cellules apparemment identiques s'explique par des rĂŽles diffĂ©rents du cytosquelette d'actine des deux cellules formant le contact. Une cellule "donneuse" polymĂ©rise de l'actine, ce qui amĂšne les membranes cellulaires en contact. La cellule "receveuse" assemble des faisceaux contractiles d'acto-myosine qui exercent localement des forces sur les jonctions et rĂ©gulent leur longueur. Des courbes de croissance de ces jonctions adhĂ©rentes ont par ailleurs Ă©tĂ© mesurĂ©es pour des cellules soumises Ă des augmentations contrĂŽlĂ©es de force contractile par incubation dans le nocodazole. L'ajustement des courbes de croissance expĂ©rimentales par des lois thĂ©oriques a permis de dĂ©terminer les forces contractiles mises en jeu par la cellule "receveuse". Le tracĂ© du diagramme force-extension des jonctions adhĂ©rentes a pu donc ĂȘtre rĂ©alisĂ© pour la premiĂšre fois et par une mĂ©thode non-invasive. Les approches biologiques pour l'identification des assemblages en jeu et physiques pour l'ajustement des lois de croissance ont l'une et l'autre montrĂ© que les contacts entre cellules se renforcent localement Ă la maniĂšre des contacts focaux. Nous avons enfin observĂ© la dynamique interne des contacts focaux en croissance par TIRFM pour diffĂ©rentes protĂ©ines participant au contact (fibronectine, intĂ©grine, vinculine, actine) afin de proposer un mĂ©canisme de mĂ©canosension.GRENOBLE1-BU Sciences (384212103) / SudocSudocFranceF
Effect of glow DBD modulation on gas and thin film chemical composition: case of Ar/SiH 4
Adhesive Properties of Silicone-Coated Release Liner Paper Enhanced by Atmospheric Pressure Plasma Pre- and Post-Treatment
For release-liner preparation, coating stabilization of the silicone layer on base paper often requires pre- and post-treatment. In this study, we used atmospheric pressure diffuse coplanar surface barrier discharge in roll-to-roll configuration. The results of prepared coating showed that the A4 size clay-coated paper sprayed with silicone oil (0.25–0.50 mL) gradually decreased the tape peeling force (180°) with prolonged and repeated air plasma post-treatment. Best results showing increased hydrophobicity and significantly enhanced release factor of the coating were obtained after the plasma treatment in a nitrogen atmosphere. The silicone coating on the clay-coated paper reduced the reference release force from 5.5 N/cm to less than 1.5 N/cm after the repeated silicone spraying and short nitrogen plasma post-treatment. The results of X-ray photoelectron spectroscopy and scanning electron microscopy indicate silicone curing by plasma post-treatment and pore-closing of base paper without changes of the bulk material. The aging test lasting 3 months revealed the stability of the prepared coating
Feasibility of Antireflection and Passivation Coatings by Atmospheric Pressure PECVD
AbstractAn innovative method to obtain antireflection and passivation coatings on p-type crystalline silicon solar cells is presented. The method consists in the growth of hydrogenated silicon nitride films (SiNx:H) by atmospheric pressure plasma enhanced chemical vapor deposition (AP-PECVD). Compared to industrial process, using this kind of processing may allow an augmentation of the silicon solar cell production throughput and yield enabling a reduction of the cost of photovoltaic systems. The optical and passivation properties of the SiNx:H films grown by AP-PECVD are determined and compared with the standard low pressure plasma enhanced chemical vapor deposition (LP- PECVD) films. Minority carrier lifetime of 1ms was reached. Solar cells coated with AP-PECVD SiNx:H films were made, and their performances were compared with standard SiNx:H coated cells. The same cell efficiency is obtained for the two groups of cells proving the interest of the AP-PECVD for the solar cell industry
Faire lâhistoire de la RĂ©sistance
DĂšs la LibĂ©ration, « faire lâhistoire de la RĂ©sistance » a Ă©tĂ© perçu comme une tĂąche posant des problĂšmes spĂ©cifiques aux historiens. On ne peut comprendre les vicissitudes dâune historiographie Ă la fois riche et complexe sans prendre en compte les moyens mis en Ćuvre pour faire face Ă ce dĂ©fi, et notamment les travaux du ComitĂ© dâhistoire de la DeuxiĂšme Guerre mondiale, qui pilota jusquâen 1980 la plupart des travaux menĂ©s sur la RĂ©sistance. Pionnier par le recours aux enquĂȘtes orales, unique par lâutilisation dâun rĂ©seau de correspondants rĂ©gionaux, anciens rĂ©sistants pour beaucoup, ce ComitĂ© est le signe le plus visible dâun phĂ©nomĂšne plus gĂ©nĂ©ral : lâimplication des rĂ©sistants et de leurs associations dans lâhistoriographie de la RĂ©sistance. Celle-ci a donc Ă©tĂ© dĂšs lâorigine au cĆur de questions aujourdâhui ressassĂ©es : la relation conflictuelle entre histoire savante et mĂ©moire individuelle et collective, la possibilitĂ© mĂȘme dâune histoire du temps prĂ©sent, les risques dâune histoire officielle â sachant que le ComitĂ© nâen Ă©tait pas moins animĂ© et pilotĂ© par des historiens professionnels, et non des moindres puisque Lucien Febvre en fut le premier prĂ©sident. OrganisĂ© par la Fondation de la RĂ©sistance et lâinstitut dâĂ©tudes politiques de Lyon, ce colloque avait donc pour enjeu dâĂ©valuer le degrĂ© de pertinence de lâaffirmation courante selon laquelle on serait passĂ© progressivement « de la mĂ©moire Ă lâhistoire », de poser les jalons pour une Ă©tude dĂ©passionnĂ©e des relations entre historiens et acteurs en histoire contemporaine et du lien entre Ă©volution historiographique et demande sociale. Sans prĂ©tendre Ă lâexhaustivitĂ©, tant le champ couvert par le ComitĂ© fut vaste, les contributions rendent compte de sa genĂšse, de ses mĂ©thodes, de ses publications, des problĂšmes rencontrĂ©s pour accĂ©der aux archives. Pour mettre en perspective son apport, dâautres acteurs de cette historiographie ont Ă©tĂ© Ă©voquĂ©s aux niveaux rĂ©gional et national mais aussi international avec les travaux des historiens anglo-saxons et le regard des historiens allemands. Des comparaisons avec la Belgique et lâEspagne ont enfin permis de mieux mesurer les problĂšmes communs Ă lâĂ©tude des rĂ©sistances en Europe
Rapport dâactivitĂ©s 2018 â Laboratoire SantĂ© Environnement et Microbiologie.
Ce rapport prĂ©sente une synthĂšse des actions, et travaux rĂ©alisĂ©s par le laboratoire SantĂ© Environnement et Microbiologie pendant lâannĂ©e 2018. Les divers projets de recherche sont rĂ©sumĂ©s et les derniers dĂ©veloppements ou rĂ©sultats sont briĂšvement Ă©voquĂ©s. Les actions en tant que Laboratoire National de RĂ©fĂ©rence pour la Microbiologie des Coquillages et les activitĂ©s pour la coordination du rĂ©seau REMI sont Ă©galement prĂ©sentĂ©es