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(474) Production(s) de l'année 2018
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Role of charge regulation and flow slip in the ionic conductance of nanopores: An analytical approach
Auteur(s): Manghi Manoel, Palmeri J., Yazda K., Henn F., Jourdain V.
(Article) Publié:
Physical Review E, vol. 98 p.012605 (2018)
Texte intégral en Openaccess :
Ref HAL: hal-01844602_v1
Ref Arxiv: 1712.01055
DOI: 10.1103/PhysRevE.98.012605
WoS: 000439065200005
Ref. & Cit.: NASA ADS
Exporter : BibTex | endNote
6 Citations
Résumé: The number of precise conductance measurements in nanopores is quickly growing. To clarify the dominant mechanisms at play and facilitate the characterization of such systems for which there is still no clear consensus, we propose an analytical approach to the ionic conductance in nanopores that takes into account (i) electro-osmotic effects, (ii) flow slip at the pore surface for hydrophobic nanopores, (iii) a component of the surface charge density that is modulated by the reservoir pH and salt concentration cs using a simple charge regulation model, and (iv) a fixed surface charge density that is unaffected by pH and cs . Limiting cases are explored for various ranges of salt concentration and our formula is used to fit conductance experiments found in the literature for carbon nanotubes. This approach permits us to catalog the different possible transport regimes and propose an explanation for the wide variety of currently known experimental behavior for the conductance versus cs .
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Colonization of non-biodegradable and biodegradable plastics by marine microorganisms
Auteur(s): Dussud Claire, Hudec Cindy
(Article) Publié:
Frontiers In Microbiology, vol. 9 p.1571 (2018)
Texte intégral en Openaccess :
Ref HAL: hal-01842397_v1
DOI: 10.3389/fmicb.2018.01571
WoS: 000439040500001
Exporter : BibTex | endNote
27 Citations
Résumé: Plastics are ubiquitous in the oceans and constitute suitable matrices for bacterial attachment and growth. Understanding biofouling mechanisms is a key issue to assessing the ecological impacts and fate of plastics in marine environment. In this study, we investigated the different steps of plastic colonization of polyolefin-based plastics, on the first one hand, including conventional low-density polyethylene (PE), additivated PE with pro-oxidant (OXO), and artificially aged OXO (AA-OXO); and of a polyester, poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), on the other hand. We combined measurements of physical surface properties of polymers (hydrophobicity and roughness) with microbiological characterization of the biofilm (cell counts, taxonomic composition, and heterotrophic activity) using a wide range of techniques, with some of them used for the first time on plastics. Our experimental setup using aquariums with natural circulating seawater during 6 weeks allowed us to characterize the successive phases of primo-colonization, growing, and maturation of the biofilms. We highlighted different trends between polymer types with distinct surface properties and composition, the biodegradable AA-OXO and PHBV presenting higher colonization by active and specific bacteria compared to non-biodegradable polymers (PE and OXO). Succession of bacterial population occurred during the three colonization phases, with hydrocarbonoclastic bacteria being highly abundant on all plastic types. This study brings original data that provide new insights on the colonization of non-biodegradable and biodegradable polymers by marine microorganisms.
Commentaires: article 1571
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Size-characterization of natural and synthetic polyisoprenes by Taylor dispersion analysis
Auteur(s): Biron Jean-Philippe, Bonfils Frédéric, Cipelletti L., Cottet Hervé
(Article) Publié:
Polymer Testing, vol. 66 p.244-250 (2018)
Texte intégral en Openaccess :
Ref HAL: hal-01837505_v1
DOI: 10.1016/j.polymertesting.2018.01.017
WoS: 000428824000029
Exporter : BibTex | endNote
Résumé: Non-aqueous Taylor dispersion analysis (TDA) was used for the size-characterization of natural and synthetic polyisoprenes (4 × 103–2 × 106 g/mol molar mass). Not only the weight-average hydrodynamic radius (Rh), but also the probability distribution of the hydrodynamic radius, were both derived from the Taylorgrams by a simple integration of the elution profile and by a more sophisticated constrained regularized linear inversion of the Taylorgram, respectively. Results in terms of size characterization (hydrodynamic radii between 2 and 100 nm) were compared to size exclusion chromatography coupled to a refractive index-based mass detector. Multimodal size distributions were resolved by TDA for industrial and natural polyisoprenes, with the advantage over the chromatographic technique that, in TDA, there is no abnormal elution of microaggregates (hydrodynamic radii ∼ 40–50 nm). Considering the importance and the difficulty of characterizing polyisoprene microaggregates, TDA appears as a promising and simple technique for the characterization of synthetic and natural rubber.
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Translational and Rotational Dynamical Heterogeneities in Granular Systems
Auteur(s): Kou Binquan, Cao Yixin, Li Jindong, Xia Chengjie, Li Zhifeng, Dong Haipeng, Zhang Ang, Zhang Jie, Kob W., Wang Yujie
(Article) Publié:
Physical Review Letters, vol. 121 p.018002-1 (2018)
Texte intégral en Openaccess :
Ref HAL: hal-01833984_v1
DOI: 10.1103/PhysRevLett.121.018002
WoS: 000437746100006
Exporter : BibTex | endNote
8 Citations
Résumé: We use X-ray tomography to investigate the translational and rotational dynamical heterogeneitiesof a three dimensional hard ellipsoids granular packing driven by oscillatory shear. We find thatparticles which translate quickly form clusters with a size distribution given by a power-law withan exponent that is independent of the strain amplitude. Identical behavior is found for particles that are translating slowly, rotating quickly, or rotating slowly. The geometrical properties of these four different types of clusters are the same as those of random clusters. Different cluster types are considerably correlated/anticorrelated, indicating a significant coupling between translational androtational degrees of freedom. Surprisingly these clusters are formed already at time scales that aremuch shorter than theα−relaxation time, in stark contrast to the behavior found in glass-forming systems.
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Large nonlocality in macroscopic Hall bars made of epitaxial graphene
Auteur(s): Nachawaty A., Yang M., Nanot S., Kazazis D., Yakimova R., Escoffier Walter, Jouault B.
(Article) Publié:
Physical Review B, vol. 98 p.045403 (2018)
Texte intégral en Openaccess :
Ref HAL: hal-01833590_v1
DOI: 10.1103/PhysRevB.98.045403
WoS: 000437110900005
Exporter : BibTex | endNote
1 Citation
Résumé: We report on nonlocal transport in large-scale epitaxial graphene on silicon carbide under an applied external magnetic field. The nonlocality is related to the emergence of the quantum Hall regime and persists up to the millimeter scale. The nonlocal resistance reaches values comparable to the local (Hall and longitudinal) resistances. At moderate magnetic fields, it is almost independent on the in-plane component of the magnetic field, which suggests that spin currents are not at play. The nonlocality cannot be explained by thermoelectric effects without assuming extraordinary large Nernst and Ettingshausen coefficients. A model based on counterpropagating edge states backscattered by the bulk reproduces quite well the experimental data.
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BOBINES HOMOGÈNES POUR LA RÉSONANCE MAGNÉTIQUE NUCLÉAIRE PORTABLE (RMN) APPLIQUÉE À L'AGROÉCOLOGIE
Auteur(s): Alibert E., Cardoso Maida, Coillot C., Hamdaoui K.El, Gatineau F., Goze-Bac C., Grondin A., Nativel Eric, de Pellegars Pauline, Rousset S., Sidi-Boulenouar R., Simon J., Techer A., Verdeil J. L., Zanca M.
Conference: Journées Thématiques Capteurs Magnétiques du GDR Ondes (GRENOBLE, FR, 2018-05-31)
Texte intégral en Openaccess :
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Energy scale of Dirac electrons in Cd3As2
Auteur(s): Hakl M., Tchoumakov S., Crassee I., Akrap A., Piot B. A., Faugeras C., Nateprov A., Arushanov E., Teppe F., Sankar R., Lee Wei-Li, Debray Jérôme, Caha O., Novak J., Goerbig M. O., Potemski M., Orlita M.
(Article) Publié:
Physical Review B, vol. 97 p.115206 (2018)
Texte intégral en Openaccess :
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