Search results for "Epos"
showing 10 items of 1649 documents
Implications for paleomobility studies of the effects of quaternary volcanism on bioavailable strontium: a test case in North Patagonia (Argentina)
2020
Strontium isotopes (⁸⁷Sr/⁸⁶Sr) are used as geochemical tracers for paleomobility studies because they display predictable and stable patterns in ecosystems primarily controlled by the underlying geological regimes. While bedrock geology is stable over thousands of years, geomorphological processes can influence the ⁸⁷Sr/⁸⁶Sr in ecosystems over archeologically relevant timescales. Among these geomorphological processes, the deposition and reworking of volcanic sediments over Quaternary timescales are little studied but could be an important control of ⁸⁷Sr/⁸⁶Sr variations in many archeological regions. North Patagonia is a key archeological region to address animal and human movements, and a…
Enquête sur les archives ouvertes françaises menée par Couperin en 2019 : résultats et analyses
2020
French Higher Education Institutions (HEIs) are, for 89% of the respondents to the survey, now having their own open repository, or declaring to be in the implementation phase (compared to 82% in 2017 and only 62% in 2014). It can therefore be considered that almost all HEIs now offer a green open access repository or signalling solution to their researchers. The « still in progress » or suspended projects are rather related to the current recomposition of the Higher Education landscape. The most obvious obstacles to the latest implementations remain both the low involvement of researchers in the project and the human resources allocated. There is a slight but real increase in the rate of i…
Enquête Archives Ouvertes COUPERIN 2017 : résultats de l’enquête
2017
Les archives ouvertes s’inscrivent de plus en plus solidement et durablement dans le paysage documentaire de l’enseignement supérieur. Si les organismes de recherche ont été précurseurs pour la création d’archives ouvertes, les grandes écoles, mais surtout les universités ont désormais massivement rejoint le mouvement. Signe de cette progression notable, 82 % des répondants disposent en 2017 d’une archive en production ou en cours de mise en œuvre, contre 62 % en 2014. L’adoption majoritaire de la plate-forme HAL (qui représente 79 % des archives en production et 84 % des archives des universités parmi les répondants) se renforce encore depuis 2014. La structuration d’un réseau des utilisat…
Les archives ouvertes : état des lieux en 2017
2018
International audience; Les archives ouvertes s’inscrivent de plus en plus solidement et durablement dans le paysage documentaire de l’enseignement supérieur. Si les organismes de recherche ont été précurseurs pour la création d’archives ouvertes, les grandes écoles, mais surtout les universités ont désormais massivement rejoint le mouvement. Signe de cette progression notable, 82 % des répondants disposent en 2017 d’une archive en production ou en cours de mise en œuvre, contre 62 % en 2014. L’adoption majoritaire de la plate-forme HAL (qui représente 79 % des archives en production et 84 % des archives des universités parmi les répondants) se renforce encore depuis 2014. La structuration …
Area‐Selective Atomic Layer Deposition on Functionalized Graphene Prepared by Reversible Laser Oxidation
2022
Publisher Copyright: © 2022 The Authors. Advanced Materials Interfaces published by Wiley-VCH GmbH. Area-selective atomic layer deposition (ALD) is a promising “bottom-up” alternative to current nanopatterning techniques. While it has been successfully implemented in traditional microelectronic processes, selective nucleation of ALD on 2D materials has so far remained an unsolved challenge. In this article, a precise control of the selective deposition of ZnO on graphene at low temperatures (<250 °C) is demonstrated. Maskless femtosecond laser writing is used to locally activate predefined surface areas (down to 300 nm) by functionalizing graphene to achieve excellent ALD selectivity (up to…
<title>Electrochromism in oxyfluoride thin films</title>
1994
Oxyfluoride films based on W and Ti were prepared by reactive sputtering in plasmas containing O2 + CF4. The deposition rate was large, particularly when chemical sputtering was promoted by heating the target. The films could show large charge insertion/extraction, high coloration efficiency, and good cycling durability.© (1994) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
Confident methods for the evaluation of the hydrogen content in nanoporous carbon microfibers
2012
Abstract Nanoporous carbon microfibers were grown by chemical vapor deposition in the vapor-liquid solid mode using different fluid hydrocarbons as precursors in different proportions. The as-grown samples were further treated in argon and hydrogen atmospheres at different pressure conditions and annealed at several temperatures in order to deduce the best conditions for the incorporation and re-incorporation of hydrogen into the microfibers through the nanopores. Since there are some discrepancies in the results on the hydrogen content obtained under vacuum conditions, in this work, we have measured the hydrogen content in the microfibers using several analytical methods in ambient conditi…
A new approach to the growth of ZnO by vapour transport
2005
The crystal growth of ZnO by vapour transport is classically made in presence of additional species which enhance the growth process. Usually, additional species have been considered as chemical transport agents that promote a typical CVT (Chemical Vapour Transport) process. Recently, we have proposed a new interpretation of the chemical role of some of these species. This new interpretation considers that, in some cases, the additional species promote a partial consumption of the O2 provided by the ZnO decomposition and, consequently, a Zn excess is generated. This excess of Zn pressure activates the ZnO decomposition and the growth rate is enhanced. Among those species, carbon shows an ad…
Observations of atmospheric chemical deposition to high Arctic snow
2017
Abstract. Rapidly rising temperatures and loss of snow and ice cover have demonstrated the unique vulnerability of the high Arctic to climate change. There are major uncertainties in modelling the chemical depositional and scavenging processes of Arctic snow. To that end, fresh snow samples collected on average every 4 days at Alert, Nunavut, from September 2014 to June 2015 were analyzed for black carbon, major ions, and metals, and their concentrations and fluxes were reported. Comparison with simultaneous measurements of atmospheric aerosol mass loadings yields effective deposition velocities that encompass all processes by which the atmospheric species are transferred to the snow. It is…
The AeroCom evaluation and intercomparison of organic aerosol in global models
2014
This paper evaluates the current status of global modeling of the organic aerosol (OA) in the troposphere and analyzes the differences between models as well as between models and observations. Thirty-one global chemistry transport models (CTMs) and general circulation models (GCMs) have participated in this intercomparison, in the framework of AeroCom phase II. The simulation of OA varies greatly between models in terms of the magnitude of primary emissions, secondary OA (SOA) formation, the number of OA species used (2 to 62), the complexity of OA parameterizations (gas-particle partitioning, chemical aging, multiphase chemistry, aerosol microphysics), and the OA physical, chemical and op…