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991.
992.
Cecile Baudin Christophe Pean Bruno Pellizzari Andree Gadelle Florence Fauvelle Jean-Claude Debouzy Jean-Pierre Dalbiez Bruno Perly 《Journal of inclusion phenomena and macrocyclic chemistry》2000,38(1-4):287-296
We report on the synthesis,characterization and ionic complexation properties ofhexakis (2-O-acetyl-3,6-anhydro)cyclomaltohexaose and hexakis (2-O-methyl-3,6-anhydro) cyclomaltohexaose usingthin-layer chromatography and Nuclear MagneticResonance spectroscopy. The selectivity towardscations depends on chemical modification of thehydroxyl groups and a very high specificity can beobtained in the case of lead for methylatedderivatives. 相似文献
993.
In the realm of topological automorphisms of totally disconnected locally compact groups, the scale function introduced by Willis in [19] is compared with the topological entropy. We prove that the logarithm of the scale function is always dominated by the topological entropy and we provide examples showing that this inequality can be strict. Moreover, we give a condition equivalent to the equality between these two invariants. Various properties of the scale function, inspired by those of the topological entropy, are presented. 相似文献
994.
995.
M. Durante C. Bruno 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2010,60(1):215-218
Exposure to cosmic radiation is today acknowledged as a major obstacle to
human missions to Mars. In fact, in addition to the poor knowledge on the
late effects of heavy ions in the cosmic rays, simple countermeasures are
apparently not available. Shielding is indeed very problematic in space,
because of mass problems and the high-energy of the cosmic rays, and
radio-protective drugs or dietary supplements are not effective. However,
the simplest countermeasure for reducing radiation risk is to shorten the
duration time, particularly the transit time to Mars, where the dose rate is
higher than on the planet surface. Here we show that using nuclear electric
propulsion (NEP) rockets, the transit time could be substantially reduced to
a point where radiation risk could be considered acceptable even with the
current uncertainty on late effects. 相似文献
996.
In this paper, we initiate the study of the Givental group action on Cohomological Field Theories in terms of homotopical algebra. More precisely, we show that the stabilisers of Topological Field Theories in genus 0 (respectively in genera 0 and 1) are in one-to-one correspondence with commutative homotopy Batalin–Vilkovisky algebras (respectively wheeled commutative homotopy BV-algebras). 相似文献
997.
Dispersion of silica nanoparticles bearing perfluorohexyl units into fluorinated copolymers
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Nelly Durand Jean‐Pierre Habas Bernard Boutevin Bruno Améduri 《Journal of polymer science. Part A, Polymer chemistry》2015,53(12):1512-1522
This study aims at determining the compatibility behavior of nanoparticles surface with fluorinated matrices to obtain a homogenous dispersion and better composites properties. First, modified silica nanoparticles by C6F13I and C6F13‐C2H4‐SH led to various fluorinated silica of different massic concentrations and grafting rates. The dispersion of these nanoparticles (in 5 wt %) into molten poly(VDF‐co‐HFP) and poly(TFE‐co‐HFP) matrices were studied as well as the hydrophobic, mechanical, and thermal properties of both fluorinated copolymers and resulting composites. In both series, the storage modulus of nanocomposites increased while the melting (Tm) and decomposition (T10%) temperatures varied with the polymer matrix. They increased for poly(VDF‐co‐HFP) composites (Tm= 134 to 144 °C and T10%= 441 to 464 °C) but decreased for poly(TFE‐co‐HFP) nanocomposites (Tm= 276 to 268 °C and T10%= 488 to 477 °C). © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015 , 53, 1512–1522 相似文献
998.
Carlos Bruno Barreto Luna Danilo Diniz Siqueira Edcleide Maria Araújo Emanuel Pereira do Nascimento Joo Baptista da Costa Agra de Melo 《先进技术聚合物》2022,33(1):111-124
Polypropylene (PP) blends with acrylonitrile-butadiene-styrene (ABS) were prepared using the styrene-ethylene-butylene-styrene copolymer (SEBS) as a compatibilizing agent. The blends were prepared in a co-rotational twin-screw extruder and injection molded. Torque rheometry, Izod impact strength, tensile strength, heat deflection temperature (HDT), differential scanning calorimetry, thermogravimetry, and scanning electron microscopy properties were investigated. The results showed that there was an increase in the torque of PA6/ABS blends with SEBS addition. The PP/ABS/SEBS (60/25/15%) blend showed significant improvement in impact strength, elongation at break, thermal stability, and HDT compared with neat PP. The elastic modulus and tensile strength have not been significantly reduced. The degree of crystallinity and the crystalline melting temperature increased, indicating a nucleating effect of ABS. The PP/ABS blends compatibilized with 12.5% and 15% SEBS presented morphology with well-distributed fine ABS particles with good interfacial adhesion. As a result, thermal stability has been improved over pure PP and the mechanical properties have been increased, especially impact strength. In general, the addition of the SEBS copolymer as the PP/ABS blend compatibilizer has the advantage of refining the blend's morphology, increasing its toughness and thermal stability, without jeopardizing other PP properties. 相似文献
999.
1000.
Bruno Bassan Claudia Ceci 《Stochastics An International Journal of Probability and Stochastic Processes》2013,85(3-4):633-649
We consider optimal stopping problems for Markov processes with a semicontinuous reward function g , and we show that under suitable conditions the value function w = w [ g ] is itself semicontinuous and is a viscosity solution of the associated variational inequality. 相似文献