Time filter

Source Type

Toulouse, France

Al-Kattan A.,National Polytechnic Institute of Toulouse | Dufour P.,Institut Universitaire de France | Dexpert-Ghys J.,CEMES | Drouet C.,National Polytechnic Institute of Toulouse
Journal of Physical Chemistry C | Year: 2010

Luminescent colloidal nanosystems based on europium-doped biomimetic apatite were prepared and investigated. The colloids were synthesized by soft chemistry in the presence of a phospholipid moiety, 2-aminoethylphosphoric acid (AEP), with varying europium doping rates. Physicochemical features, including compositional, structural, morphological, and luminescence properties, were examined. Experimental evidence showed that suspensions prepared from an initial Eu/(Eu + Ca) molar ratio up to 2% consisted of singlephased biomimetic apatite nanocrystals covered with AEP molecules. The mean particle size was found to depend closely on the AEP content, enabling the production of apatite colloids with a controlled size down to ca. 30 nm. The colloids showed luminescence properties typical of europium-doped systems with narrow emission bands and long luminescence lifetimes of the order to the millisecond, and the data suggested the location of Eu3+ ions in a common crystallographic environment for all the colloids. These systems, stable over time and capable of being excited in close-to-visible or visible light domains, may raise interest in the future in the field of medical imaging. © 2010 American Chemical Society. Source

The hardening effect of a high concentration of substitutional solute atoms in iron has been investigated by means of in situ straining experiments in FeSi and FeCr alloys, between 100 and 300 K. The results show that both screw and edge dislocations interact with solute atoms. This interaction is, however, strongest on screw dislocations, as a result of the formation of superjogs in the vicinity of solute atoms. Under such conditions, hardening takes place above a transition temperature for which the local pinning at superjogs becomes stronger than the Peierls friction stress. © 2013 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved. Source

In situ straining experiments were carried out in various FeNi, FeSi and FeCr alloys, between 95 and 300 K, in order to determine the origin of the softening effect of a low concentration of substitutional solute atoms in iron. Dislocations multiply and annihilate by glide in {1 1 0} planes and cross-slip, as in pure Fe. Curved non-screw parts are highly mobile, though they are subjected to a frictional stress which has been estimated. Straight screw segments have a slow and steady motion at all temperatures, corresponding to a classical kink-pair mechanism. In particular, they do not exhibit the transition to jerky motion that has previously been observed in pure Fe at low temperatures, and which has been correlated with the hump in the stress-temperature curve. Under such conditions, the softening effect is interpreted as being due to the shift of the transition and corresponding hump to lower temperatures, as in FeC. © 2013 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved. Source

Meffre A.,INSA Toulouse | Lachaize S.,INSA Toulouse | Gatel C.,CEMES | Respaud M.,INSA Toulouse | Chaudret B.,INSA Toulouse
Journal of Materials Chemistry | Year: 2011

This article reports the synthesis of iron(0) nanoparticles at moderate temperature - from 120 °C to 150 °C - using the reduction of the organometallic iron(ii) precursor {Fe[N(SiMe3)2] 2}2 by hexadecylamine (HDA) in the absence of dihydrogen (H2). The nanoparticles are monodisperse in size and self-assemble into 2D super-lattices suitable for transport measurements. The nanoparticles are stabilized in mesitylene by a mixture of HDA and hexadecylammonium chloride (HDA·HCl). The resulting truncated single-crystalline nanocubes have a narrow size distribution and a high magnetization close to the bulk value. The products are characterized by transmission electronic microscopy (TEM and HRTEM), SQUID measurements, Mössbauer and Infra-Red spectroscopies. Fe(ii) reduction is accompanied by oxidation of amines into imines which was detected as a by-product. This reduction occurs at 120 °C and above. The temperature, in conjunction with the reaction time, allows for a fine control of the nano-objects final size. The latter can also be tuned with the HDA·HCl concentration. Finally, this one-pot synthesis produces high-quality magnetic nanoparticles with mean sizes in the range 6 to 10 nm depending on the conditions. © 2011 The Royal Society of Chemistry. Source

Home > Press > GrapheneCanada 2016 International Conference: Recent advances in technology developments and business opportunities in graphene commercialization Abstract: The 2nd edition of Graphene & 2D Materials Canada 2016 International Conference & Exhibition (www.graphenecanadaconf.com) will take place in Montreal (Canada): 18-20 October, 2016. Graphene Canada 2016 attractive and promising program features 40 high-level Keynote and Invited speakers from all over the world, with a perfect mixture of fundamental research and industrial perspective. Top industry leaders will discuss recent advances in technology developments and business opportunities in graphene commercialization. Not to be missed: - The plenary session - An industrial forum with focus on Graphene Commercialization (Abalonyx, Alcereco Inc, AMO GmbH, Avanzare, AzTrong Inc, Bosch GmbH, China Innovation Alliance of the Graphene Industry (CGIA), Durham University & Applied Graphene Materials, Fujitsu Laboratories Ltd., Hanwha Techwin, Haydale, IDTechEx, North Carolina Central University & Chaowei Power Ltd, NTNU&CrayoNano, Phantoms Foundation, Southeast University, The Graphene Council, University of Siegen, University of Sunderland and University of Waterloo) - Extensive thematic workshops in parallel (Materials & Devices Characterization, Chemistry, Biosensors & Energy and Electronic Devices) - A significant exhibition (Abalonyx, Go Foundation, Grafoid, Group NanoXplore Inc., Raymor | Nanointegris and Suragus GmbH) The GrapheneCanada 2016 will bring together, from a global perspective, scientists, researchers, end-users, industry, policy makers and investors in an environment of cooperation and sharing towards the challenges of Graphene commercialization. Organisers: Phantoms Foundation www.phantomsnet.net Catalan Institute of Nanoscience and Nanotechnology - ICN2 (Spain) | CEMES/CNRS (France) | GO Foundation (Canada) | Grafoid Inc (Canada) | Graphene Labs - IIT (Italy) | McGill University (Canada) | Texas Instruments (USA) | Université Catholique de Louvain (Belgium) | Université de Montreal (Canada) For more information, please click If you have a comment, please us. Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.

Discover hidden collaborations