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Anionic Polymerization of Butadiene Using Lithium/Potassium Multi-metallic Systems:Influence on Polymerization Control and Polybutadiene Microstructure

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Chinese Journal of Polymer Science 2020年第4期38卷 357-362,I0006页

作者： Antoine Forens Kevin Roos Charlotte Dire Benoit Gadenne Stephane Carlotti Univ.Bordeaux CNRSBordeaux INPLCPOUMR 5629F-33600PessacFrance MFP Michelin Centre de Technologie/Ladoux23 Place des Carmes Dechaux63040 Clermont-Ferrand cedex 9France

Thermal,mechanical,and viscoelastic properties of polybutadiene-based rubber materials are highly dependent on polybutadiene *** use of polar modifier in association with alkyllithium is a well-known method to obtain polybutadiene with a high vinyl con *** approach is to use bimetallic initiating species such as alkyllithium combined to heavier alkali metal alkoxide(RONa,ROK...).The polymerization control is n evertheless not achieved and several parameters were found to influe nee *** bimetallic in itiating systems based on alkyllithium and a potassium alkoxide,alkyllithium structure,initiator preformation time,and initiator composition were identified as parameters influencing the anionic polymerization process of butadiene and/or polybutadiene *** addition,the use of trimetallic systems based on alkyllithium,potassium alkoxide,and alkylaluminum was investigated in order to prevent side reactions regardless of the[K]/[Li]ratio and of the initiator preformation time.

关键词： Polybutadiene Anionic polymerization Microstructure (Multi)metallic systems Lithium/potassium-based systems

A practical path guiding method for participating media

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Computational Visual Media 2020年第1期6卷 37-51页

作者： Hong Deng Beibei Wang Rui Wang Nicolas Holzschuch Nanjing University of Science and Technology Nanjing 210094China State Key Lab of CAD&CG Zhejiang UniversityHangzhou 310058China Univ.Grenoble-Alpes InriaCNRSGrenoble INPLJK38000 GrenobleFrance

Rendering translucent materials is costly:light transport algorithms need to simulate a large number of scattering events inside the material before reaching *** cost is especially high for materials with a large albedo or a small mean-freepath,where higher-order scattering effects *** simple terms,the paths get lost in the *** guiding has been proposed for surface rendering to make convergence faster by guiding the sampling *** this paper,we introduce a path guiding solution for translucent *** learn an adaptive approximate representation of the radiance distribution in the volume and use it to sample the scattering direction,combining it with phase function sampling by resampled importance *** proposed method significantly improves the performance of light transport simulation in participating media,especially for small lights and media with refractive *** method can handle any homogeneous participating medium,with high or low scattering,with high or low absorption,and from isotropic to highly anisotropic.

关键词： Monte Carlo ray tracing path guiding volume light transport participating media rendering

Time-dependent behaviour of the Callovo-Oxfordian claystone-concrete interface

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Journal of Rock Mechanics and Geotechnical Engineering 2020年第1期12卷 89-101页

作者： Eleni Stavropoulou Matthieu Briffaut Frédéric Dufour Guillaume Camps Univ.Grenoble Alpes CNRSGrenoble INP3SRF-38000GrenobleFrance Agence Nationale pour la gestion des Déchets Radioactifs(Andra) Chatenay-MalabryFrance

In the context of the Cigeo project,the French National Radioactive Waste Management Agency(Andra)is studying the behaviour of a deep geological facility for radioactive waste deposit in the CallovoOxfordian(COx)*** assessment of durability of this project requires the prediction of irreversible strain over a large time *** mechanical interaction of the host rock and the concrete support of tunnels must be investigated to ensure the long-term sustainability of the *** instantaneous and time-dependent behaviour of the claystone-concrete interface is experimentally investigated with direct shear tests and long-duration shear tests of a few *** mechanical and structural state of the claystone which is affected after interaction with concrete reflects to the response of the claystone-concrete interface,and thus different types of COx claystone-concrete interfaces are *** delayed deformation of the interface is found to be linked to the level of the normal loading and the loading history while a different response of the interface was observed from the short-and long-duration tests,indicating a possible progressive modification of interface under long-duration loadings.

关键词： Callovo-Oxfordian(COx)claystone Interfaces Time-dependent behaviour

Electrochemical hydrogen compression and purification versus competing technologies: Part Ⅱ. Challenges in electrocatalysis

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Chinese Journal of Catalysis 2020年第5期41卷 770-782页

作者： Marine Trégaro Maha Rhandi Florence Druart Jonathan Deseure Marian Chatenet Univ.Grenoble Alpes Univ.Savoie Mont BlancCNRSGrenoble-INPLEPMI38000 GrenobleFrance

Hydrogen will be at the basis of the World’s energy policy in forthcoming decades, owing to its decarbonized nature, at least when produced from renewables. For now, hydrogen is still essentially produced from fossil feedstock(and to a minor extent from biomass);in consequence the present hydrogen gas on the market is containing non-negligible amounts of impurities that prevent its immediate usage in specialty chemistry or as an energy carrier in fuel cells, e.g. in transportation applications(cars, buses, trains, boats, etc.) that gradually spread on the planet. For these purposes, hydrogen must be of sufficient purity but also sufficiently compressed(at high pressures, typically 70 MPa), rendering purification and compression steps unavoidable in the hydrogen cycle. As shown in the first part of this contribution "Electrochemical hydrogen compression and purification versus competing technologies: Part I. pros and cons", electrochemical hydrogen compressors(EHCs), which enable both hydrogen purification and compression, exhibit many theoretical(thermodynamic) and practical(kinetics) advantages over their mechanical counterparts. However, in order to be competitive, EHCs must operate in very intensive conditions(high current density and low cell voltage) that can only be reached if their core materials, e.g. the membrane and the electrodes/electrocatalysts, are optimized. This contribution will particularly focus on the properties electrocatalysts must exhibit to be used in EHCs: they shall promote(very) fast hydrogen oxidation reaction(HOR) in presence of impurities, which implies that they are(very) tolerant to poisons as well. This consists of a prerequisite for the operation of the anode of an EHC used for the purification-compression of hydrogen, and the materials developed for poison-tolerance in the vast literature on low-temperature fuel cells, may not always satisfy these two criteria, as this contribution will review.

关键词： Electrochemical hydrogen compression Electrochemical hydrogen purification Electrocatalysts Hydrogen oxidation Poison tolerance

Oil and fatty acid accumulation during coriander (Coriandrum sativum L.) fruit ripening under organic cultivation

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The Crop Journal 2015年第4期3卷 366-369页

作者： Quang-Hung Nguyen Thierry Talou Mureil Cerny Philippe Evon Othmane Merah Université Fédérale de Toulouse Midi-Pyrénées INP-ENSIACET Laboratoire de Chimie Agro-industrielle Institut National de Recherche Agronomique UMR 1010 CAI

To evaluate the accumulation of oil and fatty acids in coriander during fruit ripening, a field experiment was conducted under organic cultivation conditions in Auch(near Toulouse,southwestern France) during the 2009 cropping season. The percentage and composition of the fatty acids of coriander were determined by gas chromatography. Our results showed that rapid oil accumulation started in early stages(two days after flowering, DAF). Twelve fatty acids were identified. Saturated and polyunsaturated acids were the dominant fatty acids at earlier stages(2–12 DAF), but decreased after this date. After this stage,petroselinic acid increased to its highest amount at 18 DAF. In contrast, palmitic acid followed the opposite trend. Saturated and polyunsaturated fatty acids decreased markedly and monounsaturated fatty acids increased during fruit maturation. It appears that the fruit of coriander may be harvested before full maturity.

关键词： Oil content Petroselinic acid Coriander Organic cultivation Fatty acid accumulation

Impact of mycotoxin on immune response and consequences for pig health

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Animal Nutrition 2016年第2期2卷 63-68页

作者： Alix Pierron Imourana Alassane-Kpembi Isabelle P.Oswald INRA UMR 1331 ToxAlim Research Centre in Food Toxicology Universite de Toulouse INP UMR 1331 ToxAlim BIOMIN Research Center

Mycotoxins are fungal secondary metabolites detected in many agricultural commodities, especially cereals. Due to their high consumption of cereals, pigs are exposed to these toxins. In the European Union, regulations and/or recommendations exist in pig feed for aflatoxins, ochratoxin A, fumonisins,zearalenone, and trichothecenes, deoxynivalenol and T-2 toxin. These mycotoxins have different toxic effects, but they all target the immune system. They have immunostimulatory or immunosuppressive effects depending on the toxin, the concentration and the parameter investigated. The immune system is primarily responsible for defense against invading organisms. The consequences of the ingestion of mycotoxin-contaminated feed are an increased susceptibility to infectious diseases, a reactivation of chronic infection and a decreased vaccine efficacy. In this review we summarized the data available on the effect of mycotoxins on the immune system and the consequences for pig health.

关键词： Pig Mycotoxins Feed contamination Susceptibility to disease Immunity Vaccine efficacy

XPS characterization and corrosion resistance of cerium-treated magnesium coatings

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Rare Metals 2011年第4期30卷 368-373页

作者： Samia Ben Hassen Latifa Bousselmi Patrice Berot El Mustafa Rezrazi Ezzeddine Triki Unité de Recherche Corrosion & Protection des Métalliques ENITBP 37Tunis-BelvédèreTunisie Institut UTINAM CNRS UMR 6213Université de Franche-Comté16 route de Gray 25030 Besanon CedexFrance Laboratoire Traitement et Recyclage des Eaux CERTEBorj CedriaTunisie

Cerium conversion treatment was applied on magnesium coatings in a solution containing CeC13. The composition ot the cenum conversion layer on magnesium was investigated using X-ray photoelectron spectroscopy （XPS）, It was revealed that the composition predominately consisted of a three-valent state cerium compound with a relative abundance around 90%. Some of Ce^3＋ was oxidized to Ce^4＋. Electrochemical impedance spectroscopy results revealed that the total impedance of cerium-treated samples increased for a short immersion time in NaC1 solution before coating deteriorating. This deterioration was due to the coating porosity increasing and the breakdown of the conversion layer

关键词： cerium compounds magnesium coatings X-ray photoelectron spectroscopy corrosion resistance

Improvement in corrosion resistance of magnesium coating with cerium treatment

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Rare Metals 2009年第3期28卷 277-283页

作者： Samia Ben Hassen Latifa Bousselmi Patrice Berot El Mustafa Rezrazi Ezzeddine Triki Unité de Recherche Corrosion & Protection des Métalliques ENITBP 37Tunis-BelvédèreTunisia Institut UTINAM CNRS UMR 6213Université de Franche-Comté16 route de Gray 25030 Besanon CedexFrance Laboratoire Traitement et Recyclage des Eaux CERTEBorj CedriaTunisia

Corrosion protection afforded by a magnesium coating treated in cerium salt solution on steel substrate was investigated using open circuit potential, polarization curves, and electrochemical impedance spectroscopy （EIS） in 0.005 M sodium chloride solution （NaCl）. The morphology of the surface was characterized by scanning electron microscopy （SEM）, energy dispersive spectroscopy （EDS）, and X-ray diffraction （XRD）. The cerium treated coating was obtained by immersion in CeCl3 solution. The results showed that the corrosion resistance of the treated magnesium coating was improved. The corrosion potential of the treated coating was found to be nobler than that of the untreated magnesium coating and the corrosion current decreased significantly. Impedance results showed that the cerium treatment increased corrosion protection. The improvement of anti-corrosion properties was attributed to the formation of cerium oxides and hydroxides that gave rise to a physical barrier effect.

关键词： magnesium coating cerium corrosion protection impedance spectroscopy

Stability of a Viscous Liquid Film in a Rotating Cylindrical Cavity under Angular Vibrations

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Fluid Dynamics & Materials Processing 2024年第12期20卷 2693-2707页

作者： Victor Kozlov Alsu Zimasova Nikolai Kozlov Laboratory of Vibrational Hydromechanics Perm State Humanitarian Pedagogical UniversityPerm614990Russia Institut de Mécanique des Fluides de Toulouse Toulouse INPToulouse31400France

The behavior of a viscous liquid film on the wall of a rapidly rotating cylinder subjected to angular vibrations is experimentally *** cavity is filled with an immiscible low-viscosity liquid of lower *** the absence of vibrations,the high viscosity liquid covers the inner surface of the cylinder with a relatively thin axisymmetric film;the low-viscosity liquid is located in the cavity *** is found that with an increase in the amplitude of rotational vibrations,the axisymmetric interphase boundary loses *** azimuthally periodic 2D“frozen wave”appears on the film surface in a threshold *** is shown that the frozen wave excitation is associated with the oscillatory Kelvin—Helmholtz instability,and the stability threshold depends on a vibrational *** new vibrational effects in rotating cavities are studied accordingly:the stability(critical value of vibrational parameter)grows with decreasing the contrast in liquids viscosity;the rotation(the Coriolis force)stabilizes the interface–the critical value of vibrational parameter grows with the dimensionless rotation rate,the threshold is characterized by the product of the aforementioned vibrational parameter and the dimensionless rotation rate to some *** discovered phenomena can be useful for vibrational control of interfaces in many technological processes,especially in the field of materials science.

关键词： Rotation oscillations immiscible fluids interface viscosity contrast “frozen wave”instability