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61.
The systems formed by neodymium sesquioxide with respectively yttrium sesquioxide and ytterbium sesquioxide showed several very extended solid solutions at high temperature, near the melting point. The phases determined “in situ” at high temperature are often different of those obtained in annealed or quenched samples. 相似文献
62.
Luc Doyen Laurent Najman Juliette Mattioli 《Journal of Mathematical Imaging and Vision》1995,5(3):219-230
The present paper provides some differential results dealing with the morphological dilation of a compact set in the nonregular case. Indeed the evolution of dilated sets with respect to time is characterized through mutational equations which are new mathematical tools extending the concept of differential equations to the metric space of all nonempty compact sets of
n
. Using this new tool, we prove that the mutation of the dilation is the normal cone which is a generalization of the classical notion of normal. This result clearly establishes that the dilation transforms this initial set in the direction of the normal at any point of the set. Furthermore, it does not require any regularity assumptions on the compact set. 相似文献
63.
Manuel Baca Emmanuel de la Rochefoucauld Emmanuelle Ambroise Jean-Marc Krafft Redouane Hajjar Pascal P. Man Xavier Carrier Juliette Blanchard 《Microporous and mesoporous materials》2008,110(2-3):232-241
Mesoporous aluminas of controlled pore sizes were synthesized by multiple grafting of Al isopropoxide in organic solvents on mesoporous silica SBA-15. These materials were characterized by N2 physisorption, TEM, XRD, 27Al NMR and their surface chemical properties were probed by DRIFT, cumene cracking and MoO3 thermal spreading. The results show that the chemical nature of the Al-grafted materials varies continuously with the number of grafting from pure silica to pure alumina. Typically, after three graftings, this original method of synthesis allows one to prepare ordered mesoporous aluminas with specific surface areas above 300 m2 g−1 and a narrow pore size distribution centered on ca. 60 Å. In addition to the characterizations, different models were developed to understand the evolution of the specific surface area and to discard a possible pore blocking. 相似文献
64.
65.
Preparation of Ru metal nanoparticles in mesoporous materials: influence of sulfur on the hydrogenating activity 总被引:4,自引:0,他引:4
Peng Tian Juliette Blanchard Katia Fajerwerg Michle Breysse Michel Vrinat Zhongmin Liu 《Microporous and mesoporous materials》2003,60(1-3):197-206
Hydrogenating catalysts were prepared by inserting Ru into the pores of mesoporous Al-MCM-41 materials by selective adsorption of [Ru(NH3)6]3+. Ru/support catalysts were obtained after reduction with H2. The activities of these catalysts in hydrogenation reactions were compared to those of Ru/HY and Ru/SiO2. The catalytic properties in the absence of sulfur were tested in benzene hydrogenation, and the intrinsic activities of all the catalysts (either supported on mesoporous materials or on zeolites) were identical. It was concluded from this result that the dispersion of the Ru metallic phase was similar for all these catalysts. These samples were tested in the tetralin hydrogenation in pure H2 and in the presence of H2S (330 ppm of H2S in H2). They were found to be much less active than the zeolite-supported catalysts in the presence of H2S. It is proposed that the lower activity of the catalysts supported on mesoporous materials is either due to their milder acidity, as evidenced by NH3-TPD, cumene cracking and pyridine desorption experiments, or to the localization of the Ru nanoparticles on alumina islands. 相似文献
66.
European Journal of Wood and Wood Products - Engineered hardwood floors are taking more and more market shares but remain underused in non-residential buildings such as public, heavy traffic areas... 相似文献
67.
This paper describes a new social networking site, Cloudworks, which aims to provide a dynamic environment for finding, sharing and discussing learning and teaching ideas and designs. The paper begins by discussing the mismatch between the potential application of technologies in education and their actual use in practice. It considers some of the reasons for this and suggests ways in which this gap might be addressed. It goes on to outline the vision behind the development of Cloudworks, the phases of development and findings to date. It then contextualises this work theoretically drawing in particular on the notion of ‘social objects’ and a framework for sociality. The paper concludes with a discussion of the implications of this work and future research plans. 相似文献
68.
Juliette Chevy Claude Fressengeas Mikhail Lebyodkin Vincent Taupin Pierre Bastie Paul Duval 《Acta Materialia》2010,58(5):1837-1849
Hard X-ray diffraction experiments have provided evidence of a strongly heterogeneous distribution of dislocation densities along the axis of cylindrical ice single crystals oriented for basal slip in torsion creep. The dislocation arrangements showed a complex scale-invariant character, which was analyzed by means of statistical and multifractal techniques. A trend to decreasing autocorrelation of the dislocation distribution was observed as deformation proceeds. At low strain levels, long-range spatial correlations control the distribution, but short-range correlations in relation with cross-slip progressively prevail when strain increases. This trend was reproduced by a model based on field dislocation dynamics, a theory accounting for both long-range elastic interactions and short-range interactions through transport of dislocation densities. 相似文献
69.
Relationships between soil organic matter, nutrients, bacterial community structure, and the performance of microbial fuel cells 总被引:2,自引:0,他引:2
Dunaj SJ Vallino JJ Hines ME Gay M Kobyljanec C Rooney-Varga JN 《Environmental science & technology》2012,46(3):1914-1922
Microbial fuel cells (MFCs) offer the potential for generating electricity, mitigating greenhouse gas emissions, and bioremediating pollutants through utilization of a plentiful renewable resource: soil organic carbon. We analyzed bacterial community structure, MFC performance, and soil characteristics in different microhabitats within MFCs constructed from agricultural or forest soils in order to determine how soil type and bacterial dynamics influence MFC performance. Our results indicated that MFCs constructed from agricultural soil had power output about 17 times that of forest soil-based MFCs and respiration rates about 10 times higher than forest soil MFCs. Agricultural soil MFCs had lower C:N ratios, polyphenol content, and acetate concentrations than forest soil MFCs. Bacterial community profile data indicate that the bacterial communities at the anode of the high power MFCs were less diverse than in low power MFCs and were dominated by Deltaproteobacteria, Geobacter, and to a lesser extent, Clostridia, while low-power MFC anode communities were dominated by Clostridia. These results suggest that the presence of organic carbon substrate (acetate) was not the major limiting factor in selecting for highly electrogenic bacterial communities, while the quality of available organic matter may have played a significant role in supporting high performing bacterial communities. 相似文献
70.
Coudrain P. Magnan P. Batude P. Gagnard X. Leyris C. Vinet M. Castex A. Lagahe-Blanchard C. Pouydebasque A. Cazaux Y. Giffard B. Ancey P. 《Electron Devices, IEEE Transactions on》2009,56(11):2403-2413
A new 3-D CMOS image sensor architecture is presented as a potential candidate for submicrometer pixels. To overcome the scaling challenge related to miniaturized pixel design rules, far beyond traditional 3-D stacking alignment capabilities, a sequential construction is applied. This paper gives a technical overview of this 3-D scheme and validates a part of its building blocks. As a consequence of a sequential process, the thermal budget is limited to ensure bottom device immunity. Subsequently, high-quality SOI film transfer above the first layer by direct bonding and etch back is demonstrated. Finally, the low-temperature processing of HfO2/TiN fully depleted silicon-on-insulator readout transistors is detailed and evaluated from a low frequency noise point of view. 相似文献