Search results for "E-F"
showing 10 items of 836 documents
High efficiency of Pt2+ - CeO2 novel thin film catalyst as anode for proton exchange membrane fuel cells
2016
Abstract The elevated price of Pt limits the large-scale implementation of commercial proton exchange membrane fuel cells, which effectively convert chemical energy into electricity. In order to increase the cost-efficiency in proton-exchange membrane fuel cells, we have designed a family of novel anode catalysts consisting of thin films of ceria with low Pt loadings sputtered on a nanostructured carbon support. Remarkably, only such small amounts of Pt are necessary for achieving power density values comparable to the reference commercial catalysts, which results in excellent specific activities of our samples. By combining photoelectron spectroscopy and catalytic performance analysis, we …
Les cimetières celtiques du Bassin parisien (VIIe-IIe siècle av. J.-C.) : systèmes typologique et chronologique
2016
International audience; Les cimetières celtiques du Bassin parisien ont livré un riche ensemble d’artefacts. Leur analyse est restée longtemps difficile en l’absence de nomenclature utilisable. Luc Baray offre ici une synthèse complète des systèmes typologique et chronologique, s’appuyant sur plusieurs centaines d’objets mis au jour dans 1 500 sépultures, qui ont été décrits et classés en 905 types différents. Fondée sur une analyse morphométrique fine, cette étude propose six grands systèmes de classement typologiques pour les céramiques, les parures (torques, bracelets, bagues, anneaux de cheville, boucles d’oreilles, perles, pendeloques), les accessoires vestimentaires (fibules, ceinture…
Therapeutic implications of Cancer Initiating Cells.
2009
Background: Until few years ago, all neoplastic cells within a tumour were suggested to have tumorigenic capacity, but recent evidences hint to the possibility that such feature is confined to a subset of Cancer Initiating Cells (CICs), also called Cancer Stem Cells (CSCs). These cells are the reservoir of the heterogeneous populations of differentiated cancer cells constituting the tumour bulk. Mechanisms shared with somatic stem cells, such as quiescence, self-renewal ability, asymmetric division and multidrug resistance, allow to these cells to drive tumour growth and to evade conventional therapy. Objective: Here, we give a brief overview on the origin of CICs, the mechanisms involved i…
Clostridium baratii bacteremia associated with Kawasaki syndrome. First case report
2007
We experienced a case of a 3-year-old boy who presented signs and symptoms of Kawasaki syndrome. Two blood culture sets were processed by the hospital microbiology laboratory using a standard blood culturing system. The anaerobic bottles gave a positive result at day 3 after inoculation. The biochemical profiles produced by the RapID ANA II System showed that the organism was Clostridium baratii with a probability of 99%. Our case highlights the importance of C. baratii as a potential human pathogen and reports the associations with manifestations, which, to our knowledge, have not been previously described concomitantly with a clostridial infection.
Complexes de métaux de transition avec des ligands carbènes N-hétérocycliques : synthèses et réactivité
2015
The purpose of this work is the synthesis of complexes containing imine-functionalized protic NHC ligands in order to further develop synthetic methodologies giving access to pNHC, C-bound ‘anionic’ imidazolide, and homo- and heterodinuclear complexes. In the case of imidazoles without functional group, deprotonation with n-butyl lithium afforded (1-aryl-1H-imidazol-2-yl)lithium in good yield. Reaction of (1-aryl-1H-imidazol-2-yl)lithium with [Ir(cod)(μ-Cl)]2 or [Rh(cod)(μ-Cl)]2 yielded a doubly C2,N3-bridged dinuclear complex. In the case of imine-functionalized imidazole, the Ir(I) N-bound imidazole complex can tautomerize to Ir(I) imine-functionalized pNHC complex chloride abstraction at…
An optimized mass storage FFT for vector computers
1995
Abstract The performance of a segmented FFT algorithm which allows the out-of-core computation of the Fourier transform of a very large mass storage data array is presented. The code is particularly optimized for vector computers. Tests performed mainly on a CONVEX C210 vector computer showed that, for very long transforms, tuning of the main parameters involved leads to computation speed and global efficiency better than for FFTs performed in-core. The use of tunable parameters allows optimization of the algorithm on machines with different configurations.
Interphase Model and Phase-Field Approach for Strain Localization
2020
Quasi-brittle materials subjected to a high level of mechanical solicitations see the development in relatively narrow zone of micro-cracks that coalesce into stress free cracks. In this work, the problem of strain localization in elastoplastic materials exhibiting softening has been approached by applying the interphase model together with the phase-field theory. In particular, the narrow zone where strains concentrate, usually named process zone or localization band, is kinematically modeled using the interphase model, while the phase-field variable is introduced to regularize the contact strains at the interface between the plastic strain band and the surrounding material. This correspon…
Solid state NMR investigation of the roman Acqualadroni rostrum: tenth year assessment of the consolidation treatment of the wooden part
2020
Abstract: This work follows a previous one dealing with the state of conservation study of the wooden part of the roman Acqualadroni rostrum soon after its finding in the seabed of Acqualadroni (Messina, Italy). The archaeological survey and recovery were particularly relevant since this artefact is one of the two rostrums, nowadays known,found together with its wooden part. Following the recovery, it was consolidated by immersion in a melamine-formaldehyde resin (Kauramin) aqueous solution for eight months at the “Centro di Restauro del Legno Bagnato” (Pisa, Italy). The present investigation is aimed to determine at microscopic scale the wood state of conservation and to highlight interact…
An evolutionary method for complex-process optimization
2010
10 páginas, 7 figuras, 7 tablas
Area-efficient FPGA-based FFT processor
2003
A novel architecture for computing the fast Fourier transform on programmable devices is presented. Main results indicate that the use of one CORDIC operator to perform the multiplication by all the ‘twiddle factors’ sequentially leads to an area saving up to 35% with respect to other cores.