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991.
Nano-Micro Letters - A facile and rapid method to synthesize graphene/layered double hydroxide (LDH) nanohybrids by a microwave technique is demonstrated. The synthesis procedure involves... 相似文献
992.
Toughening of poly(lactide) using polyethylene glycol methyl ether acrylate: Reactive versus physical blending 下载免费PDF全文
Georgio Kfoury Jean‐Marie Raquez Fatima Hassouna Philippe Leclère Valérie Toniazzo David Ruch Philippe Dubois 《Polymer Engineering and Science》2015,55(6):1408-1419
To design high‐performance poly(lactide)‐based materials (PLA‐based) with improved toughness, two approaches based on the reactive extrusion (REx) process are investigated and compared in the present study. The first approach relies upon a two‐step procedure using a REx‐polymerized poly(ethylene glycol) methyl ether acrylate, i.e., poly(AcrylPEG), as a highly‐branched and compatible impact modifier for PLA. The free‐radical polymerization proves to be very efficient with a peroxide initiator concentration of 1 wt%. The as‐produced poly(AcrylPEG) is then melt‐blended with PLA by extrusion. The resulting materials exhibit largely increase impact resistance (ca. 35 kJ/m2) in presence of 20 wt% poly(AcrylPEG) in comparison with neat PLA (2.7 kJ/m2), while moderate ductility (tensile elongation at break <40%) and limited plasticization effect are observed. The second “one‐step” approach consists in in situ grafting of AcrylPEG onto PLA backbone via a one‐stage REx. The resulting materials exhibit substantially improved impact resistance (ca. 102 kJ/m2) for AcrylPEG loading of 20 wt%, high ductility (tensile elongation at break of ca. 150%) and efficient plasticization. A detailed characterization of the morphology of the materials has been performed using PF‐QNM‐AFM to better elucidate the structure‐property relationships. POLYM. ENG. SCI., 55:1408–1419, 2015. © 2015 Society of Plastics Engineers 相似文献
993.
994.
Ciprian Teodorov Luka Le Roux Zo Drey Philippe Dhaussy 《Software Testing, Verification and Reliability》2016,26(7):516-542
Model‐checking enables the automated formal verification of software systems through the explicit enumeration of all the reachable states. While this technique has been successfully applied to industrial systems, it suffers from the state‐space explosion problem because of the exponential growth in the number of states with respect to the number of interacting components. In this paper, we present a new reachability analysis algorithm, named Past‐Free[ze], that reduces the state‐space explosion problem by freeing parts of the state‐space from memory. This algorithm relies on the explicit isolation of the acyclic parts of the system before analysis. The parallel composition of these parts drives the reachability analysis, the core of all model‐checkers. During the execution, the past states of the system are freed from memory making room for more future states. To enable counter‐example construction, the past states can be stored on external storage. To show the effectiveness of the approach, the algorithm was implemented in the OBP Observation Engine and was evaluated both on a synthetic benchmark and on realistic case studies from automotive and aerospace domains. The benchmark, composed of 50 test cases, shows that in average, 75% of the state‐space can be dropped from memory thus enabling the exploration of up to 14 times more states than traditional approaches. Moreover, in some cases, the reachability analysis time can be reduced by up to 25%. In realistic settings, the use of Past‐Free[ze] enabled the exploration of a state‐space 4.5 times larger on the automotive case study, where almost 50% of the states are freed from memory. Moreover, this approach offers the possibility of analyzing an arbitrary number of interactions between the environment and the system‐under‐verification; for instance, in the case of the aerospace example, 1000 pilot/system interactions could be analyzed unraveling an 80 GB state‐space using only 10 GB of memory. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
995.
The microstructural analysis of 1,4-cis- and of 1,4-trans-polymyrcene was conducted by means of thorough investigations at a very high field NMR (21.1T, 900 MHz). A set of 1D and 2D experiments helped to entirely assign the resonances of the spectra for both stereoisomers. A simple method to distinguish between each stereoisomer by NMR spectroscopy is finally provided. 相似文献
996.
Hassen Bouchékif Deniz Tunc Cédric Le Coz Alain Deffieux Philippe Desbois Stéphane Carlotti 《Polymer》2014
The controlled synthesis of polyamide 6 chemical networks by anionic ring-opening copolymerization of ε-caprolactam (CL) with synthesized bis-ε-caprolactam derived from α-amino-ε-caprolactam, i.e. N-functionalized α-amino-ε-caprolactam bis-monomers, using sodium ε-caprolactamate as an initiator and hexamethylene-1,6-dicarbamoylcaprolactam as di-functional fast activator was examined in bulk at 140 °C. An urea-based bis-monomer and CL were first shown to copolymerize with a decreasing polymerization rate due to side reactions. On the contrary, quantitative copolymerization of CL with various amounts of bis-N(2-oxo-3-azepanyl)-1,6-tetramethylenediamide, an amide-based bis-monomer, leads to fast kinetics similar to the homopolymerization of CL. Crosslinked PA6 with network exhibiting elastic or viscoelastic behaviors, depending on the amount of crosslinker, were observed and characterized by swelling in hexafluoroisopropanol, dynamic mechanical analysis and rheology measurements. Crystallinity and swelling were shown to decrease with the increasing content of the crosslinking agent. 相似文献
997.
Le Cloarec MF Bonté P Lefèvre I Mouchel JM Colbert S 《The Science of the total environment》2007,375(1-3):125-139
The activity of environmental radionuclides ((7)Be, (210)Pb and (137)Cs) was monitored in nested catchments, inside the Seine River basin. Suspended matter data was collected at 8 different watersheds, ranging from order 1 to order 7, and ranging in size over 4 orders of magnitude. Suspended matter was analyzed for (210)Pb, (137)Cs and (7)Be, and used to calculate the flux of sediments out of each watershed. Monthly atmospheric flux data of (210)Pb and (7)Be was analyzed to assess the input flux of each into the watersheds, taking into account the rainfall during sampling periods. Taking advantage of the different half-lives of (7)Be (53 days) and (210)Pb (22 years), a two-box model was built for each of the catchments following a methodology previously developed by Dominik et al. [Dominik J, Burrus D, Vernet JP. Transport of the environmental radionuclides in alpine watershed. Earth Planet Sci Letters 1987; 84: 165-180.]. The model divides the watershed into a soil box and a rapid reservoir and provides insight into the removal rate of suspended matter from the surrounding watershed. The model enables the assessment of the surface area and the residence time of slow and rapid reservoirs to describe the fate of contaminants of atmospheric origin inside the river basin. The model was improved by considering the dissolved fraction in the total flux and adding the (137)Cs inventory as an additional constraint. The effects of these changes are discussed. Residence times in the soil box, characterized by low transport velocity, range between 4800 years at Melarchez (order 1) to about 30000 years at Andresy and Poses (order 7). They remain constant in each watershed over a large range of variation of atmospheric fluxes of (7)Be and (210)Pb during the whole study, but are sensitive to SM variations. The residence time in the rapid box, which includes the surface of the river and immediate surroundings, is less than one year, while its surface area is in the range 0.6% to 2.2% of the total catchment area. They are sensitive to (7)Be atmospheric flux variations. The two-box model was used to estimate the amount of the radionuclides in each reservoir. Inventories appear to be constant from one watershed to the next. The (7)Be inventory ratio in the rapid and slow boxes expresses the rate of particle-reactive atmospheric pollutants that will be rapidly delivered to the river. 相似文献
998.
This study investigates the effect of various dietary saturated fatty acid (SFA) profiles on plasma lipid parameters and tissue
fatty acid composition in rats. The experiment was designed to monitor polyunsaturated fatty acids (PUFA) levels, while examining
different amounts and types of SFA. Four isocaloric diets were prepared, containing 10–11 mol% of fatty acids (FA) as linoleic
acid (LNA) and 2.5 mol% as α-linolenic acid (ALA), leading to an identical and well-balanced LNA/ALA ratio. The initial rapeseed
oil/corn oil mixture providing ALA and LNA was enriched with olive oil to prepare the olive oil diet. The butterfat diet was
supplemented with butterfat, containing short-chain SFA (C4:0–C10:0, 17 mol% of FA), lauric acid (C12:0, 3.2 mol%), myristic
acid (C14:0, 10.5 mol%) and palmitic acid (C16:0, 14.5 mol%). The saturates diet was supplemented with trilaurin, trimyristin
and tripalmitin to obtain the same level of lauric, myristic and palmitic acids as the butterfat diet, without the short-chain
SFA. The trimyristin diet was enriched with trimyristin only. The results showed that the butterfat diet contributed to specific
effects, compared to the olive oil diet and the saturates and trimyristin diets: a decrease in plasma total, LDL- and HDL-cholesterol,
higher tissue storage of ALA and LNA, and a higher level of (n-3) highly unsaturated fatty acids in some tissues. This study
supports the hypothesis that in diets with identical well-balanced LNA/ALA ratios, short chain SFA may decrease circulating
cholesterol and increase tissue polyunsaturated fatty acid content in the rat. 相似文献
999.
Edouard Kraffe Jacques Grall Elena Palacios Citlali Guerra Philippe Soudant Yanic Marty 《Lipids》2010,45(5):437-444
The present study aimed to elucidate the effective phylogenetic specificity of distribution of a cis-4,7,10, trans-13-22:4 (22:4(n-9)Δ13trans) among pectinids. For this purpose, we extended the analysis of membrane glycerophospholipids FA composition to 13 species
of scallops, covering 11 genera and 7 tribes representatives of the three subfamilies Chlamydinae, Palliolinae and Pectininae
and the subgroup Aequipecten. In species belonging to the subfamily Pectininae and the Aequipecten subgroup, 22:4(n-9)Δ13trans was found in substantial amounts, but it was absent in other species belonging to the subfamilies Chlamydinae and Palliolinae.
Homologous non-methylene-interrupted (NMI) FA, also hypothesized to differ along phylogenetic lines in bivalves, were totally
absent or present only in trace amounts in representatives of the Aequipecten subgroup but ranged from 0.3 to 4.5% of the
total FA in Pectinidae, Chlamydinae, and Palliolinae subfamilies. The species-specific occurrence of NMI and 22:4(n-9)Δ13trans FA in membrane lipids of pectinids agrees with the most recent phylogenies based on shell morphology and molecular characteristics.
We examined the potential timing of the appearance of 22:4(n-9)Δ13trans in pectinids on a geologic time scale. 相似文献
1000.
Jean‐Philippe Laviolette Gregory S. Patience Jamal Chaouki 《American Institute of Chemical Engineers》2010,56(11):2850-2859
A novel spectroscopic method was developed to measure quantitatively and simultaneously solids volume fraction (1?ε) and gaseous species composition (Yi) in a gas/solid system. The method was comprised of an FT‐IR coupled to a fiber‐optic probe that could perform real‐time and in situ measurements of absorbance. The effect of (1?ε) and Yi on the absorbance spectra were additive and could be independently calibrated. Experiments were conducted with alkane/nitrogen mixtures and two types of particles: sand and FCC. Fuel mole fractions and (1?ε) were varied between 1.8–10.1 mol % and 0–0.45, respectively. The relative errors for Yi time‐averaged measurements were below 6% and the error increased significantly with decreasing beam intensity. A proof of concept for a novel application in fluidized beds was also completed: the fiber‐optic probe was used to measure the molar fraction of a tracer gas inside the emulsion and bubble phases during gas tracer experiments. © 2010 American Institute of Chemical Engineers AIChE J, 2010 相似文献