209 results on '"Alain Léger"'
Search Results
2. Theia: science cases and mission profiles for high precision astrometry in the future
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Fabien Malbet, Lucas Labadie, Alessandro Sozzetti, Gary Mamon, Mike Shao, Renaud Goullioud, Alain Léger, Mario Gai, Alberto Riva, Deborah Busonero, Thierry Lépine, Manon Lizzanna, Alexis Brandeker, and Eva Villaver
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Earth and Planetary Astrophysics (astro-ph.EP) ,Cosmology and Nongalactic Astrophysics (astro-ph.CO) ,Astrophysics - Solar and Stellar Astrophysics ,Astrophysics of Galaxies (astro-ph.GA) ,FOS: Physical sciences ,Astrophysics - Instrumentation and Methods for Astrophysics ,Astrophysics - Astrophysics of Galaxies ,Instrumentation and Methods for Astrophysics (astro-ph.IM) ,Solar and Stellar Astrophysics (astro-ph.SR) ,Astrophysics - Cosmology and Nongalactic Astrophysics ,Astrophysics - Earth and Planetary Astrophysics - Abstract
High-precision astrometry well beyond the capacities of Gaia will provide a unique way to achieve astrophysical breakthroughs, in particular on the nature of dark matter, and a complete survey of nearby habitable exoplanets. In this contribution, we present the scientific cases that require a flexibly-pointing instrument capable of high astrometric accuracy and we review the best mission profiles that can achieve such observations with the current space technology as well as within the boundary conditions defined by space agencies. We also describe the way the differential astrometric measurement is made using reference stars within the field. We show that the ultimate accuracy can be met without drastic constrains on the telescope stability., Comment: SPIE Conference : "Space Telescopes and Instrumentation 2022: Optical, Infrared, and Millimeter Wave", 17-22 July 2022, Montr\'eal
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- 2022
3. L-band nulling interferometry at the VLTI with Asgard/Hi-5: status and plans
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Denis Defrère, Azzurra Bigioli, Colin Dandumont, Germain Garreau, Romain Laugier, Marc-Antoine Martinod, Olivier Absil, Jean-Philippe Berger, Emilie Bouzerand, Benjamin Courtney-Barrer, Alexandre Emsenhuber, Steve Ertel, Jonathan Gagne, Adrian M. Glauser, Simon Gross, Michael J. Ireland, Harry-Dean Kenchington Goldsmith, Jacques Kluska, Stefan Kraus, Lucas Labadie, Victor Laborde, Alain Léger, Jarron Leisenring, Jérôme Loicq, Guillermo Martin, Johan Morren, Alexis Matter, Alexandra Mazzoli, Kwinten Missiaen, Salman Muhammad, Marc Ollivier, Gert Raskin, Hélène Rousseau, Ahmed Sanny, Simon Verlinden, Bart Vandenbussche, Julien Woillez, Merand, A, Sallum, S, and Sanchez-Bermudez, J
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Technology ,Science & Technology ,high contrast imaging ,optical fibers ,exozodiacal disks ,FOS: Physical sciences ,CONSTRAINTS ,Optics ,DUST ,Astronomy & Astrophysics ,VLTI ,long baseline interferometry ,exoplanets ,Physical Sciences ,Nulling interferometry ,DISCS ,Astrophysics - Instrumentation and Methods for Astrophysics ,Instrumentation and Methods for Astrophysics (astro-ph.IM) ,Instruments & Instrumentation ,high angular resolution - Abstract
Hi-5 is the L'-band (3.5-4.0 $\mu$m) high-contrast imager of Asgard, an instrument suite in preparation for the visitor focus of the VLTI. The system is optimized for high-contrast and high-sensitivity imaging within the diffraction limit of a single UT/AT telescope. It is designed as a double-Bracewell nulling instrument producing spectrally-dispersed (R=20, 400, or 2000) complementary nulling outputs and simultaneous photometric outputs for self-calibration purposes. In this paper, we present an update of the project with a particular focus on the overall architecture, opto-mechanical design of the warm and cold optics, injection system, and development of the photonic beam combiner. The key science projects are to survey (i) nearby young planetary systems near the snow line, where most giant planets are expected to be formed, and (ii) nearby main sequence stars near the habitable zone where exozodiacal dust that may hinder the detection of Earth-like planets. We present an update of the expected instrumental performance based on full end-to-end simulations using the new GRAVITY+ specifications of the VLTI and the latest planet formation models., Comment: 16 pages, 9 figures, SPIE 2022 "Astronomical Telescopes and Instrumentation" manuscript 12183-16
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- 2022
4. Extending Web Service Composition Languages with Semantic Data Flow.
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Freddy Lécué, Alexandre Delteil, and Alain Léger
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- 2009
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5. Optimizing Causal Link Based Web Service Composition.
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Freddy Lécué, Alexandre Delteil, and Alain Léger
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- 2008
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6. DL Reasoning and AI Planning for Web Service Composition.
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Freddy Lécué, Alain Léger, and Alexandre Delteil
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- 2008
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7. Towards the composition of stateful and independent semantic web services.
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Freddy Lécué, Alexandre Delteil, and Alain Léger
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- 2008
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8. Applying Abduction in Semantic Web Service Composition.
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Freddy Lécué, Alexandre Delteil, and Alain Léger
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- 2007
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9. The Semantic Web from an Industry Perspective.
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Alain Léger, Johannes Heinecke, Lyndon J. B. Nixon, Pavel Shvaiko, Jean Charlet, Paola Hobson, and François Goasdoué
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- 2006
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10. Semantic Web Service Composition through a Matchmaking of Domain.
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Freddy Lécué and Alain Léger
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- 2006
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11. Semantic Web Service Composition Based on a Closed World Assumption.
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Freddy Lécué and Alain Léger
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- 2006
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12. A Formal Model for Web Service Composition.
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Freddy Lécué and Alain Léger
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- 2006
13. A Formal Model for Semantic Web Service Composition.
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Freddy Lécué and Alain Léger
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- 2006
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14. Semantic Web applications: Fields and Business cases. The Industry challenges the research.
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Alain Léger, Lyndon J. B. Nixon, Pavel Shvaiko, and Jean Charlet
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- 2005
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15. On Identifying Knowledge Processing Requirements.
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Alain Léger, Lyndon J. B. Nixon, and Pavel Shvaiko
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- 2005
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16. An Ontology-based Mediation Architecture for E-commerce Applications.
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óscar Corcho, Asunción Gómez-Pérez, Alain Léger, Christophe Rey, and Farouk Toumani
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- 2003
17. Technology Survey on Knowledge Based Multilinguality.
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Alain Léger and Malek Boualem
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- 2003
18. sslGolog: When conditional compositions of web services meet semantic links and causal laws.
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Freddy Lécué, Alexandre Delteil, and Alain Léger
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- 2011
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19. Self-Organization and Learning in MultiAgent Based Brokerage Services.
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Marie-Pierre Gleizes, Alain Léger, Eleutherios Athanassiou, and Pierre Glize
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- 1999
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20. Abrose: A Cooperative Multi-agent Based Framework for Marketplace.
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Eleutherios Athanassiou, Peter Barrett, Delia Chirichescu, Marie-Pierre Gleizes, Pierre Glize, Dimitrios Katsoulas, Alain Léger, José Ignacio Moreno, and Hans Schlenker
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- 1999
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21. JPEG-1 standard 25 years: past, present, and future reasons for a success.
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Graham Hudson, Alain Léger, Birger Niss, Istvan Sebestyén, and Jørgen Vaaben
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- 2018
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22. Towards a Semantic State Transition System for Automated Generation of Data Flow in Web Service Composition.
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Freddy Lécué, Alexandre Delteil, and Alain Léger
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- 2009
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23. Web Service Composition as a Composition of Valid and Robust Semantic Links.
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Freddy Lécué, Alexandre Delteil, Alain Léger, and Olivier Boissier
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- 2009
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24. Les web services sémantiques, automate et intégration I. Introduction, éléments et scénarios, découverte de services web.
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Mohand-Said Hacid, Freddy Lécué, Alain Léger, Christophe Rey, and Farouk Toumani
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- 2009
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25. Les web services sémantiques, automate et intégration II. Composition de services web, technologies et plateformes, applications industrielles.
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Freddy Lécué, Alain Léger, and R. Hassen
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- 2009
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26. Conceptual Modelling for Information Filtering in Broadcast Interactive Video Applications.
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Yamina Abiza, Alain Léger, and Marion Créhange
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- 1996
27. On automating Web services discovery.
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Boualem Benatallah, Mohand-Said Hacid, Alain Léger, Christophe Rey, and Farouk Toumani
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- 2005
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28. The Workshops at the Twentieth National Conference on Artificial Intelligence.
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Diego Mollá Aliod, Eduardo Alonso, Srinivas Bangalore, Joseph E. Beck, Bir Bhanu, Jim Blythe, Mark S. Boddy, Amedeo Cesta, Marko Grobelnik, Dilek Hakkani-Tür, Sanda M. Harabagiu, Alain Léger, Deborah L. McGuinness, Stacy Marsella, Natasa Milic-Frayling, Dunja Mladenic, Daniel Oblinger, Paul E. Rybski, Pavel Shvaiko, Stephen F. Smith, Biplav Srivastava, Sheila Tejada, Hannes Högni Vilhjálmsson, Kristinn R. Thórisson, Gökhan Tür, José Luis Vicedo González, and Holger Wache
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- 2005
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29. Semantic Difference in ALN.
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Alain Léger, Christophe Rey, and Farouk Toumani
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- 2007
30. A General Framework for Covering Concepts using Terminologies.
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Boualem Benatallah, Mohand-Said Hacid, Alain Léger, Christophe Rey, and Farouk Toumani
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- 2007
31. Faint objects in motion: the new frontier of high precision astrometry
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Jordi Portell, Ariel Goobar, Alain Léger, Barbara McArthur, Renaud Goullioud, Pat Scott, Carme Jordi, Katherine Freese, Douglas Spolyar, Antonaldo Diaferio, John A. Tomsick, Gary A. Mamon, Luisa Ostorero, Glenn J. White, Rory Barnes, Paulo J. V. Garcia, Eva Villaver, L. Chemin, Torsten A. Enßlin, Berry Holl, Warren R. Brown, Conrado Albertus, Malcolm Fridlund, Hamish A. Clark, Miguel de Val-Borro, Christophe Le Poncin-Lafitte, Fabien Malbet, Mariateresa Crosta, Jean-Pierre Prost, Ummi Abbas, Erik Høg, Celine Boehm, Morgane Fortin, Sergei A. Klioner, Ariane Lançon, Oleg Y. Gnedin, D. L. Harrison, Lukasz Wyrzykowski, Alcione Mora, Laura L. Watkins, Aldo S. Bonomo, Daniel Michalik, Philippe Thebault, Frederic Courbin, Nigel Hambly, Andrew D. Holland, Lucas Labadie, Micaela Oertel, Melvyn B. Davies, Manuel A.V. Ribeiro da Silva, Hervé Bouy, Andreas Quirrenbach, Alberto Krone-Martins, Wesley A. Traub, Rosemary F. G. Wyse, Vitor Cardoso, J. Schneider, Xavier Luri, Jeremy Darling, Marco Castellani, Arnaud Siebert, André Moitinho de Almeida, Matthew W. Muterspaugh, Mario G. Lattanzi, Neil J. Murray, A. J. Falcão, David Hobbs, Paulo Gordo, Mario Damasso, Monica Valluri, António Amorim, Jacques Laskar, Yoshiyuki Yamada, Mario Gai, Alexandre C. M. Correia, Leonidas A. Moustakas, João Alves, Alexis Brandeker, David Hall, Antonio da Silva, Guillem Anglada-Escudé, Nicholas A. Walton, Antoine Crouzier, Alessandro Sozzetti, M. Shao, A. Mourao, Malbet, F [0000-0002-8029-4226], Apollo - University of Cambridge Repository, National Aeronautics and Space Administration (US), Swiss National Science Foundation, Polish National Agency for Academic Exchange, Swedish National Space Agency, Fundação para a Ciência e a Tecnologia (Portugal), Australian Research Council, Agenzia Spaziale Italiana, Ministerio de Ciencia, Innovación y Universidades (España), Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Centre National d'Études Spatiales [Toulouse] (CNES)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Météo-France -Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Météo-France, School of Physics [Sydney], The University of Sydney, CENTRA, Universidade de Lisboa, Queen Mary University of London (QMUL), Stockholm University, Ecole Polytechnique Fédérale de Lausanne (EPFL), Max Planck Institute for Astrophysics, Max-Planck-Gesellschaft, UNINOVA / CTS, Campus FCT/UNL, University of Texas at Austin [Austin], Observatoire Astronomique de l'Université de Genève (ObsGE), Université de Genève = University of Geneva (UNIGE), University of Cologne, Institut d'astrophysique spatiale (IAS), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales [Paris] (CNES), Institut d'Astrophysique de Paris (IAP), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Aurora Technology BV, Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), INAF - Osservatorio Astrofisico di Torino (OATo), Istituto Nazionale di Astrofisica (INAF), Centro de Astrobiologia [Madrid] (CAB), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Universidad de Granada = University of Granada (UGR), University of Vienna [Vienna], Department of Astronomy [Seattle], University of Washington [Seattle], Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Harvard-Smithsonian Center for Astrophysics (CfA), Harvard University-Smithsonian Institution, INAF - Osservatorio Astronomico di Roma (OAR), University of Antofogasta, Department of Physics, University of Coimbra, Universidade de Coimbra [Coimbra], Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics (LESIA), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), University of Colorado [Boulder], Lund University [Lund], Dipartimento di Fisica [Torino], Università degli studi di Torino = University of Turin (UNITO), Istituto Nazionale di Fisica Nucleare, Sezione di Torino (INFN, Sezione di Torino), Istituto Nazionale di Fisica Nucleare (INFN), Copernicus Astronomical Center of the Polish Academy of Sciences (CAMK), Polish Academy of Sciences (PAN), Leiden Observatory [Leiden], Universiteit Leiden, Chalmers University of Technology [Gothenburg, Sweden], Faculdade de Engenharia da Universidade do Porto (FEUP), Universidade do Porto = University of Porto, University of Michigan [Ann Arbor], University of Michigan System, The Open University [Milton Keynes] (OU), University of Edinburgh, Institute of Astronomy [Cambridge], University of Cambridge [UK] (CAM), Lund Observatory, Niels Bohr Institute [Copenhagen] (NBI), Faculty of Science [Copenhagen], University of Copenhagen = Københavns Universitet (UCPH)-University of Copenhagen = Københavns Universitet (UCPH), Institut de Ciencies del Cosmos (ICCUB), Universitat de Barcelona (UB), Lohrmann Observatory, Technische Universität Dresden = Dresden University of Technology (TU Dresden), Observatoire astronomique de Strasbourg (ObAS), Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Systèmes de Référence Temps Espace (SYRTE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), ESA - ESTEC (Netherlands), Columbia State Community College, Laboratoire Univers et Théories (LUTH (UMR_8102)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Thales Alenia Space [Toulouse] (TAS), THALES [France], Heidelberg University, University of Queensland [Brisbane], Imperial College London, Instítuto de Astrofísica e Ciências do Espaço [Lisboa], Faculdade de Ciencias da Universidade de Lisboa, Space Sciences Laboratory [Berkeley] (SSL), University of California [Berkeley] (UC Berkeley), University of California (UC)-University of California (UC), Planetary Science Institute [Tucson] (PSI), European Space Agency (Baltimore) Space Telescope Science Institute (ESA), Space Science and Technology Department [Didcot] (RAL Space), STFC Rutherford Appleton Laboratory (RAL), Science and Technology Facilities Council (STFC)-Science and Technology Facilities Council (STFC), Astronomical Observatory [Warsaw], Faculty of Physics [Warsaw] (FUW), University of Warsaw (UW)-University of Warsaw (UW), Johns Hopkins University (JHU), Department of Physics [Kyoto], Kyoto Sangyo University, Theia, ANR-11-LABX-0013,FOCUS,Des détecteurs pour Observer l'Univers(2011), European Project: 787886,COSMICLENS, Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA), Université de Genève (UNIGE), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), University of Granada [Granada], Smithsonian Institution-Harvard University [Cambridge], Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), Università degli studi di Torino (UNITO), Universiteit Leiden [Leiden], Universidade do Porto, University of Copenhagen = Københavns Universitet (KU)-University of Copenhagen = Københavns Universitet (KU), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), Thales Alenia Space [Cannes], Thales Alenia Space, University of California [Berkeley], University of California-University of California, Université Paris-Sud - Paris 11 (UP11)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7), Observatoire de Paris - Site de Paris (OP), Centre National de la Recherche Scientifique (CNRS)-Observatoire de Paris, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)
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Computer science ,[SDU.ASTR.CO]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO] ,[SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP] ,PLANET ,shape ,01 natural sciences ,Space mission ,Local universe ,galaxies ,010303 astronomy & astrophysics ,media_common ,Earth and Planetary Astrophysics (astro-ph.EP) ,High Energy Astrophysical Phenomena (astro-ph.HE) ,[SDU.ASTR.HE]Sciences of the Universe [physics]/Astrophysics [astro-ph]/High Energy Astrophysical Phenomena [astro-ph.HE] ,Exoplanets ,James Webb Space Telescope ,Astrophysics::Instrumentation and Methods for Astrophysics ,Local Group ,Astrometry ,Cosmology ,neutron-stars ,EQUATION-OF-STATE ,16. Peace & justice ,GALAXIES ,SHAPE ,[SDU.ASTR.GA]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Galactic Astrophysics [astro-ph.GA] ,Astrophysics::Earth and Planetary Astrophysics ,Astrophysics - Instrumentation and Methods for Astrophysics ,Astrophysics - High Energy Astrophysical Phenomena ,Astrophysics - Cosmology and Nongalactic Astrophysics ,Cosmology and Nongalactic Astrophysics (astro-ph.CO) ,NEUTRON-STARS ,black-hole ,equation-of-state ,media_common.quotation_subject ,Milky Way ,FOS: Physical sciences ,Astrophysics::Cosmology and Extragalactic Astrophysics ,MASS ,0103 physical sciences ,DARK-MATTER ,[PHYS.PHYS.PHYS-INS-DET]Physics [physics]/Physics [physics]/Instrumentation and Detectors [physics.ins-det] ,010306 general physics ,Instrumentation and Methods for Astrophysics (astro-ph.IM) ,Astrophysics::Galaxy Astrophysics ,[SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR] ,Astronomy ,Astronomy and Astrophysics ,Astrophysics - Astrophysics of Galaxies ,Galaxy ,Redshift ,Universe ,[SDU.ASTR.IM]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Instrumentation and Methods for Astrophysic [astro-ph.IM] ,HYPERVELOCITY STARS ,dark-matter ,planet ,Space and Planetary Science ,Sky ,Astrophysics of Galaxies (astro-ph.GA) ,BLACK-HOLE ,GALACTIC-HALO ,mass ,galactic-halo ,[PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph] ,hypervelocity stars ,Astrophysics - Earth and Planetary Astrophysics - Abstract
The authors would like to thank the researchers and engineers who are not coauthors of this paper but who have taken part and have brought their contribution to the proposed missions to ESA successive calls: NEAT (M3), micro-NEAT (S1), and Theia (M4 and M5). An extensive list of supporters for the science objectives is given in [17]. We thank also Arianna Gallo for her contribution in our investigation of the shape of the MilkyWay dark matter halo and Krzysztof A. Rybicki who generated the plots from Fig. 14. We are grateful to the anonymous referee who helped to improve the quality of the paper with his/her remarks. Concerning the funding of our work, we would like to acknowledge the support of many agencies or programs. R.B. acknowledges support from NASA’s Virtual Planetary Laboratory lead team under cooperative agreements NNA13AA93A. A.C.M.C. acknowledges support from CFisUC strategic project (UID/FIS/04564/2019). F.C. acknowledges support by the Swiss National Science Foundation (SNSF) and by the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation program (COSMICLENS: grant agreement No. 787886). M.F. received support from Polish National Science Centre (NCN) under Grant No. 2017/26/D/ST9/00591. M.F. gratefully acknowledge the support of the Swedish National Space Agency (DNR 65/19, 174/18). D.H. thanks the Swedish National Space Agency (SNSA/Rymdstyrelsen) for their support. A.M. thanks the Portugese Fundac¸ ˜ao para a Ciˆencia e a Tecnologia (FCT) through the Strategic Programme UID/FIS/00099/2019 for CENTRA. P.S. acknowledges support from the Australian Research Council under grant FT190100814. L.W. acknowledges support from the Polish NCN grants: Harmonia No. 2018/06M/ST9/00311 and Daina No. 2017/27/L/ST9/03221. The OATo team acknowledges partial funding by the Italian Space Agency (ASI) under contracts 2014-025-R.1.2015 and 2018-24-HH.0, and by a grant from the Italian Ministry of Foreign Affairs and International Cooperation (ASTRA). A.C. and F.M. acknowledge support by the LabEx FOCUS ANR-11-LABX-0013. The work of C.J., X.L. and J.P. was supported by the Spanish Ministry of Science, Innovation and University (MICIU/FEDER, UE) through grants RTI2018-095076-B-C21, ESP2016-80079-C2-1-R, and the Institute of Cosmos Sciences University of Barcelona (ICCUB, Unidad de Excelencia ’Mar´ıa de Maeztu’) through grants MDM-2014-0369 and CEX2019-000918-M. A.K.-M., A.A., V.C., P.G., P.G., A.M.A., A.M., M.S. were supported by Fundac¸ ˜ao para a Ciˆencia e a Tecnologia, with grants reference UIDB/00099/ 2020 and SFRH/BSAB/142940/2018 (P.G. only). A.D. and L.O. also acknowledge partial support from the Italian Ministry of Education, University and Research (MIUR) under the Departments of Excellence grant L.232/2016, and from the INFN grant InDark. G.J.W. gratefully acknowledges support of an Emeritus Fellowship from The Leverhulme Trust. EV is supported by Spanish grant PGC2018-101950-B-100. This research has made use of NASA’s Astrophysics Data System Bibliographic Services. Open access funding provided by Istituto Nazionale di Astrofisica within the CRUI-CARE Agreement., Sky survey telescopes and powerful targeted telescopes play complementary roles in astronomy. In order to investigate the nature and characteristics of the motions of very faint objects, a flexibly-pointed instrument capable of high astrometric accuracy is an ideal complement to current astrometric surveys and a unique tool for precision astrophysics. Such a space-based mission will push the frontier of precision astrometry from evidence of Earth-mass habitable worlds around the nearest stars, to distant Milky Way objects, and out to the Local Group of galaxies. As we enter the era of the JamesWebb Space Telescope and the new ground-based, adaptive-optics-enabled giant telescopes, by obtaining these high precision measurements on key objects that Gaia could not reach, a mission that focuses on high precision astrometry science can consolidate our theoretical understanding of the local Universe, enable extrapolation of physical processes to remote redshifts, and derive a much more consistent picture of cosmological evolution and the likely fate of our cosmos. Already several missions have been proposed to address the science case of faint objects in motion using high precision astrometry missions: NEAT proposed for the ESA M3 opportunity, micro-NEAT for the S1 opportunity, and Theia for the M4 and M5 opportunities. Additional new mission configurations adapted with technological innovations could be envisioned to pursue accurate measurements of these extremely small motions. The goal of this White Paper is to address the fundamental science questions that are at stake when we focus on the motions of faint sky objects and to briefly review instrumentation and mission profiles., NASA’s Virtual Planetary Laboratory NNA13AA93A, CFisUC strategic project (UID/FIS/04564/2019), Swiss National Science Foundation (SNSF), European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation program (COSMICLENS: grant agreement No. 787886), Polish National Science Centre (NCN) under Grant No. 2017/26/D/ST9/00591, Swedish National Space Agency (DNR 65/19, 174/18), Swedish National Space Agency (SNSA/Rymdstyrelsen), Portugese Fundacão para a Ciência e a Tecnologia (FCT) through the Strategic Programme UID/FIS/00099/2019 for CENTRA, Australian Research Council under grant FT190100814, Polish NCN grants: Harmonia No. 2018/06M/ST9/00311 and Daina No. 2017/27/L/ST9/03221, Italian Space Agency (ASI) under contracts 2014-025-R.1.2015 and 2018-24-HH.0, Italian Ministry of Foreign Affairs and International Cooperation (ASTRA), LabEx FOCUS ANR-11-LABX-0013, Spanish Ministry of Science, Innovation and University (MICIU/FEDER, UE) through grants RTI2018-095076-B-C21, ESP2016-80079-C2-1-R, Institute of Cosmos Sciences University of Barcelona (ICCUB, Unidad de Excelencia ’Mar´ıa de Maeztu’) through grants MDM-2014-0369 and CEX2019-000918-M, Fundacão para a Ciência e a Tecnologia, with grants reference UIDB/00099/ 2020 and SFRH/BSAB/142940/2018 (P.G. only), Italian Ministry of Education, University and Research (MIUR) under the Departments of Excellence grant L.232/2016, and from the INFN grant InDark, Emeritus Fellowship from The Leverhulme Trust, Spanish grant PGC2018-101950-B-100, Istituto Nazionale di Astrofisica within the CRUI-CARE Agreement
- Published
- 2021
32. Modeling Logical and Temporal Synchronization in Hypermedia Systems.
- Author
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Patrick Sénac, Michel Diaz, Alain Léger, and Pierre de Saqui-Sannes
- Published
- 1996
- Full Text
- View/download PDF
33. Dynamic discovery of e-services.
- Author
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Mohand-Said Hacid, Alain Léger, Christophe Rey, and Farouk Toumani
- Published
- 2002
34. Computing Concept Covers: a Preliminary Report.
- Author
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Mohand-Saïd Hacid, Alain Léger, Christophe Rey, and Farouk Toumani
- Published
- 2002
35. Using the MHEG Standard in the Hypermedia System Multicard.
- Author
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Antoine Rizk, Francis Malezieux, and Alain Léger
- Published
- 1994
36. Rôle de la classification statistique dans la compression du signal d'image : panorama et étude de cas.
- Author
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Nadia Ghazzali, Alain Léger, and Israël-César Lerman
- Published
- 1994
37. Web services: the story so far - an academic and industrial account.
- Author
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Alain Léger
- Published
- 2008
- Full Text
- View/download PDF
38. A Linearly Elastic Shell over an Obstacle: The Flexural Case
- Author
-
Alain Léger and Bernadette Miara
- Subjects
Surface (mathematics) ,Mechanical Engineering ,010102 general mathematics ,Mathematical analysis ,Shell (structure) ,Boundary (topology) ,Unilateral contact ,Geometry ,Bending ,01 natural sciences ,Displacement (vector) ,Domain (mathematical analysis) ,010101 applied mathematics ,Flexural strength ,Mechanics of Materials ,General Materials Science ,0101 mathematics ,Mathematics - Abstract
We study the equilibrium of a three-dimensional solid having a uniform thickness $2 \varepsilon $ along a middle surface which satisfies the usual assumptions of shell theory. The solid is linearly elastic at small strains and is submitted to unilateral contact conditions with an obstacle on a part of its boundary. When $\varepsilon $ tends to zero, the three-dimensional domain tends to a two-dimensional one, so that the contact conditions pass from a part of the boundary to the interior of the domain. We restrict our attention to the so-called bending case, that is when the shell undergoes only inextensional deformations. As a major difference with the case of a shallow shell, we get in general a coupling between the three components of the displacement in the contact conditions. The work is closed by explicit examples showing the corresponding variation of the non-penetrability condition along the surface of the shell and by comments about the model and the remaining difficulties.
- Published
- 2017
39. The complicated bifurcation of an archetypal self-excited SD oscillator with dry friction
- Author
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Zhi-Xin Li, Qingjie Cao, and Alain Léger
- Subjects
Period-doubling bifurcation ,Applied Mathematics ,Mechanical Engineering ,Aerospace Engineering ,Ocean Engineering ,Saddle-node bifurcation ,Bifurcation diagram ,01 natural sciences ,010305 fluids & plasmas ,Nonlinear Sciences::Chaotic Dynamics ,Transcritical bifurcation ,Classical mechanics ,Pitchfork bifurcation ,Control and Systems Engineering ,0103 physical sciences ,Homoclinic bifurcation ,Bogdanov–Takens bifurcation ,Electrical and Electronic Engineering ,Infinite-period bifurcation ,010306 general physics ,Nonlinear Sciences::Pattern Formation and Solitons ,Mathematics - Abstract
In this paper, we investigate the local and global bifurcation behaviors of an archetypal self-excited smooth and discontinuous oscillator driven by moving belt friction. The belt friction is described in the sense of Stribeck characteristic to formulate the mathematical model of the proposed system. For such a friction characteristic, the complicated bifurcation behaviors of the system are discussed. The bifurcation of the multiple sliding segments for this self-excited system is exhibited by analytically exploring the collision of tangent points. The Hopf bifurcation of this self-excited system with viscous damping is analyzed by making the examination of the eigenvalues at the steady state and discussing the stability of the limit cycles. The bifurcation diagrams and the corresponding phase portraits are depicted to demonstrate the complicated dynamical behaviors of double tangency bifurcation, the bifurcation of sliding homoclinic orbit to a saddle, subcritical Hopf bifurcation and grazing bifurcation for this system.
- Published
- 2017
40. On the coupling of large deformations and elastic-plasticity in the mechanics of a simple system
- Author
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Alain Léger, Alain Cimetière, Elaine Pratt, Institut Pprime (PPRIME), Université de Poitiers-ENSMA-Centre National de la Recherche Scientifique (CNRS), Surface, Interfaces et MAtériaux sous Contrainte SIMAC (SIMAC), Département Physique et Mécanique des Matériaux (Département Physique et Mécanique des Matériaux), Université de Poitiers-ENSMA-Centre National de la Recherche Scientifique (CNRS)-Université de Poitiers-ENSMA-Centre National de la Recherche Scientifique (CNRS)-Institut Pprime (PPRIME), Université de Poitiers-ENSMA-Centre National de la Recherche Scientifique (CNRS)-Université de Poitiers-ENSMA-Centre National de la Recherche Scientifique (CNRS), THALES Aerospace, THALES [France], Laboratoire de Mécanique et d'Acoustique [Marseille] (LMA ), Aix Marseille Université (AMU)-École Centrale de Marseille (ECM)-Centre National de la Recherche Scientifique (CNRS), and THALES
- Subjects
Constitutive equation ,[PHYS.MPHY]Physics [physics]/Mathematical Physics [math-ph] ,02 engineering and technology ,Kinematics ,Plasticity ,Tangent modulus ,Incremental plasticity ,Nonsmooth non linearity ,Plastic buckling ,[SPI.AUTO]Engineering Sciences [physics]/Automatic ,0203 mechanical engineering ,[PHYS.QPHY]Physics [physics]/Quantum Physics [quant-ph] ,[PHYS.MECA.MEFL]Physics [physics]/Mechanics [physics]/Fluid mechanics [physics.class-ph] ,[PHYS.MECA.BIOM]Physics [physics]/Mechanics [physics]/Biomechanics [physics.med-ph] ,Bifurcation ,Physics ,[SPI.ACOU]Engineering Sciences [physics]/Acoustics [physics.class-ph] ,[PHYS.MECA.VIBR]Physics [physics]/Mechanics [physics]/Vibrations [physics.class-ph] ,Critical load ,Mechanical Engineering ,[SPI.FLUID]Engineering Sciences [physics]/Reactive fluid environment ,[SPI.NRJ]Engineering Sciences [physics]/Electric power ,[CHIM.MATE]Chemical Sciences/Material chemistry ,Large deformations ,[PHYS.MECA.MSMECA]Physics [physics]/Mechanics [physics]/Materials and structures in mechanics [physics.class-ph] ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,[PHYS.MECA.ACOU]Physics [physics]/Mechanics [physics]/Acoustics [physics.class-ph] ,Nonlinear system ,[SPI.ELEC]Engineering Sciences [physics]/Electromagnetism ,020303 mechanical engineering & transports ,Classical mechanics ,[CHIM.POLY]Chemical Sciences/Polymers ,Buckling ,Mechanics of Materials ,Simple model ,[PHYS.MECA.THER]Physics [physics]/Mechanics [physics]/Thermics [physics.class-ph] ,0210 nano-technology - Abstract
International audience; The buckling and the post buckling of a simple model involving both large deformations and elastic-plasticity are studied. Plasticity is described by the classical incremental constitutive law involving in particular non regularized transition between plastic loading and elastic unloading. The kinematics is chosen in order to take into account any rotation, however large, without having to resort to approximations or asymptotic expansions. The work focusses essentially on the specificity of the coupling between these two types of nonlinearity. At small strains the global behavior is correctly given by Hutchinson's simple model involving the same elastic-plastic constitutive law and linearized deformations. But at very large strains, the response notably differs from that of Hutchinson's model. Indeed plasticity seems to have no effect and the behavior is that of a system involving the same nonlinear deformations but with a constant modulus. From the point of view of bifurcation analysis this result is qualitatively interesting due to the fact that the elastic-plastic constitutive law can be regarded as a strong, or non-smooth, nonlinearity, whereas large deformations is a smooth, we could say weaker, non linearity, so that the result contradicts the intuition that the strongest non linearity should be associated with the strongest bifurcation effect. The analysis is carried out using two different geometrical nonlinearities.
- Published
- 2019
41. Capillarity in pressure infiltration: improvements in characterization of high-temperature systems
- Author
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C. Bacciarini, Alain Léger, Raphaël Charvet, Willy Dufour, Ludger Weber, N. R. Calderon, and Andreas Mortensen
- Subjects
010302 applied physics ,Materials science ,Capillary action ,Mechanical Engineering ,Metal matrix composite ,02 engineering and technology ,Penetration (firestop) ,021001 nanoscience & nanotechnology ,01 natural sciences ,Mechanics of Materials ,0103 physical sciences ,Solid mechanics ,General Materials Science ,Wetting ,Composite material ,0210 nano-technology ,Saturation (chemistry) ,Relative permeability ,Porosity - Abstract
In the pressure infiltration of metal matrix composites, molten metal is injected under external pressure into a porous preform of the reinforcing material. Equilibrium capillary parameters characterizing wetting for this process are summarized in plots of metal saturation versus applied pressure, also known as drainage curves. Such curves can be measured in our laboratory during a single experiment with an infiltration apparatus designed to track the rate of metal penetration into porous preforms under conditions characteristic of metal matrix composite processing (temperatures in excess of 1000 A degrees C and pressures in the order of 10 MPa). For such measurements to be valid, infiltration of the preform with molten metal must be mechanically quasi-static, i.e., the metal must flow at a rate sufficiently low for the metal pressure to be essentially uniform across the preform at all times. We examine this requirement quantitatively, using a finite-difference model that simulates the unsaturated unidirectional ingress of molten metal into a ceramic particle preform of finite width. We furthermore present improvements in the experimental apparatus developed in our laboratory to measure the entire drainage curve in a single experiment. We compare numerical results with new experimental data for the copper/alumina system to show (i) that pressurization rates sufficiently low for quasi-static infiltration can be produced with this apparatus, and (ii) that taking the relative permeability equal to the saturation yields better agreement with experiment than does the expression originally proposed by Brooks and Corey.
- Published
- 2018
42. Coronographie interferéntielle pour la mission spatuale DARWIN: expérience de validation en laboratoire
- Author
-
Bertrand P. Mennesson, Pascal Puget, Patrick Bouchareine, J. M. Mariotti, Fabien Malbet, Alain Léger, Vincent Coudé du Foresto, Guy Michel, G. E. Artzner, Jacqueline Brunaud, and M. Ollivier
- Subjects
Darwin (ADL) ,Philosophy ,Humanities - Abstract
This paper, “Coronographie interferentielle pour la mission spatuale DARWIN: experience de validation en laboratoire," was presented as part of International Conference on Space Optics—ICSO 1997, held in Toulouse, France.
- Published
- 2018
43. Nulling interferometry for the darwin mission: laboratory demonstration experiment
- Author
-
Guy Michel, Alain Léger, Alain Labèque, Predrag Sekulic, and M. Ollivier
- Subjects
Wavefront ,Physics ,Interferometry ,Optics ,business.industry ,Astronomical interferometer ,Darwin (spacecraft) ,Angular resolution ,business ,Optical filter ,High dynamic range ,Exoplanet - Abstract
The DARWIN mission is a project of the European Space Agency that should allow around 2012 the search for extrasolar planets and a spectral analysis of their potential atmosphere in order to evidence gases and particularly tracers of life. The principle of the instrument is based on the Bracewell nulling interferometer. It allows high angular resolution and high dynamic range. However, this concept, proposed more than 20 years ago, has never been experimentally demonstrated in the thermal infrared with high levels of extinction. We present here a laboratory monochromatic experiment dedicated to this goal. A theoretical and numerical approach of the question highlights a strong difficulty: the need for very clean and homogeneous wavefronts, in terms of intensity, phase and polarisation distribution. A classical interferometric approach appears to be insufficient to reach our goals. We have shown theoretically then numerically that this difficulty can be surpassed if we perform an optical filtering of the interfering beams. This technique allows us to decrease strongly the optical requirements and to view very high interferometric contrast measurements with commercial optical pieces. We present here a laboratory interferometer working at 10,6 microns, and implementing several techniques of optical filtering (pinholes and single-mode waveguides), its realisation, and its first promising results. We particularly present measurements that exhibit stable visibility levels better than 99,9% that is to say extinction levels better than 1000.
- Published
- 2017
44. The equilibrium stability for a smooth and discontinuous oscillator with dry friction
- Author
-
Alain Léger, Qingjie Cao, and Zhi-Xin Li
- Subjects
Lyapunov function ,Mathematics::Dynamical Systems ,Invariance principle ,Mechanical Engineering ,Mathematical analysis ,Computational Mechanics ,Type (model theory) ,01 natural sciences ,Instability ,Stability (probability) ,Stable manifold ,010305 fluids & plasmas ,symbols.namesake ,Classical mechanics ,0103 physical sciences ,symbols ,010301 acoustics ,Saddle ,Mathematics ,Hyperbolic equilibrium point - Abstract
In this paper, we investigate the equilibrium stability of a Filippov-type system having multiple stick regions based upon a smooth and discontinuous (SD) oscillator with dry friction. The sets of equilibrium states of the system are analyzed together with Coulomb friction conditions in both $$(f_{\mathrm{n}}, f_{\mathrm{s}})$$ and $$(x, {\dot{x}})$$ planes. In the stability analysis, Lyapunov functions are constructed to derive the instability for the equilibrium set of the hyperbolic type and LaSalle’s invariance principle is employed to obtain the stability of the non-hyperbolic type. Analysis demonstrates the existence of a thick stable manifold and the interior stability of the hyperbolic equilibrium set due to the attractive sliding mode of the Filippov property, and also shows that the unstable manifolds of the hyperbolic-type are that of the endpoints with their saddle property. Numerical calculations show a good agreement with the theoretical analysis and an excellent efficiency of the approach for equilibrium states in this particular Filippov system. Furthermore, the equilibrium bifurcations are presented to demonstrate the transition between the smooth and the discontinuous regimes.
- Published
- 2015
45. Influence of the wetting angle on capillary forces in pressure infiltration
- Author
-
Alain Léger, Andreas Mortensen, and Ludger Weber
- Subjects
010302 applied physics ,Wetting angle ,Materials science ,Polymers and Plastics ,Capillary action ,Invasion percolation ,Alumina ,Metals and Alloys ,02 engineering and technology ,Liquid metal infiltration ,021001 nanoscience & nanotechnology ,Ceramic particle ,01 natural sciences ,Electronic, Optical and Magnetic Materials ,Contact angle ,Sessile drop technique ,Wetting transition ,0103 physical sciences ,Ceramics and Composites ,Wetting ,Composite material ,0210 nano-technology ,Porous medium ,Saturation (chemistry) ,Work of immersion - Abstract
This work probes the influence of wetting on pressure infiltration. Pressure/saturation curves for the infiltration of packed F1000 angular alumina particle preforms by liquid Cu-Al and Sn-Al alloys are measured using an instrumented high-temperature pressure infiltration apparatus. These are ceramic metal systems in which the contact angle is documented to vary significantly with alloying, from non-wetting to wetting conditions. We show that adding Al to Sn or to Cu modifies the early percolation-dominated phases of infiltration and also the later, pore geometry dominated, phase of the infiltration process. Changes in contact angle brought by alloying cause the saturation/pressure curves to shift, yet for all systems of this work the curves remain entirely in the range of positive pressures, despite a transition to contact angles below 90. Combining measured pressures for infiltration at fixed saturation with relevant sessile drop experiment data from the literature shows that for, the range of conditions explored here, the infiltration pressures required are proportional, not to the work of immersion, but to a linear function thereof. This result agrees qualitatively with prior work in the literature on the infiltration of non-metallic liquids in porous media, and provides a master curve by means of which saturation curves and sessile drop data can be reconciled for this particular packed ceramic particle preform. (C) 2015 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.
- Published
- 2015
46. A Smooth and Discontinuous Oscillator : Theory, Methodology and Applications
- Author
-
Qingjie Cao, Alain Léger, Qingjie Cao, and Alain Léger
- Subjects
- Nonlinear theories, Chaotic behavior in systems
- Abstract
This is the first book to introduce the irrational elliptic function series, providing a theoretical treatment for the smooth and discontinuous system and opening a new branch of applied mathematics. The discovery of the smooth and discontinuous (SD) oscillator and the SD attractors discussed in this book represents a further milestone in nonlinear dynamics, following on the discovery of the Ueda attractor in 1961 and Lorenz attractor in 1963.This particular system bears significant similarities to the Duffing oscillator, exhibiting the standard dynamics governed by the hyperbolic structure associated with the stationary state of the double well. However, there is a substantial departure in nonlinear dynamics from standard dynamics at the discontinuous stage. The constructed irrational elliptic function series, which offers a way to directly approach the nature dynamics analytically for both smooth and discontinuous behaviours including the unperturbed periodic motions and the perturbed chaotic attractors without any truncation, is of particular interest. Readers will also gain a deeper understanding of the actual nonlinear phenomena by means of a simple mechanical model: the theory, methodology, and the applications in various interlinked disciplines of sciences and engineering. This book offers a valuable resource for researchers, professionals and postgraduate students in mechanical engineering, non-linear dynamics, and related areas, such as nonlinear modelling in various fields of mathematics, physics and the engineering sciences.
- Published
- 2017
47. The exoplanet program of the microarcsecond astrometric observatory Theia (Conference Presentation)
- Author
-
Lucas Labadie, Stuart Shaklan, Fabien Malbet, Alain Léger, Alberto Krone-Martins, Celine Boehm, and Antoine Crouzier
- Subjects
Telescope ,Stars ,Planet ,Observatory ,law ,Astronomy ,Astrophysics ,Astrometry ,Circumstellar habitable zone ,Exoplanet ,Geology ,Metrology ,law.invention - Abstract
The Theia mission, as a natural successor to Gaia, will be the first extremely-high-precision astrometric surveyor that may emerge from the last ESA M5 call in October 2016. A major objective of Theia in the context of this conference is the detection by astrometry of Earths and Super-Earths exoplanets in the habitable zone of nearby A to M stars. This can be done by astrometry from space if a motion of
- Published
- 2017
48. A Smooth and Discontinuous Oscillator
- Author
-
Alain Léger and Qingjie Cao
- Subjects
Physics ,Classical mechanics - Published
- 2017
49. Erratum to: A Smooth and Discontinuous Oscillator
- Author
-
Alain Léger and Qingjie Cao
- Subjects
Physics ,Classical mechanics - Published
- 2017
50. Infiltration of tin bronze into alumina particle beds: influence of alloy chemistry on drainage curves
- Author
-
Ludger Weber, Alain Léger, and Andreas Mortensen
- Subjects
Materials science ,Mechanical Engineering ,Alloy ,Metallurgy ,engineering.material ,infiltration ,composite material ,alumina ,bronze ,Surface tension ,percolation ,Sessile drop technique ,fractal ,Mechanics of Materials ,Percolation ,Volume fraction ,engineering ,Particle ,General Materials Science ,Wetting ,Composite material ,Saturation (chemistry) - Abstract
The wetting of angular alumina particle preforms by Cu-Sn alloys is investigated by means of pressure infiltration experiments conducted at 1150 A degrees C, using a system enabling dynamic and precise measurements of the metal volume injected into the preform. Wetting is quantified in terms of drainage curves, which plot the volume fraction of molten metal in the packed powder preform (also called saturation) versus the applied pressure. The shape of the curves confirms earlier findings, namely (i) the initial stage of infiltration is dominated by percolation and obeys a universal scaling relation while the metal shape is fractal; and (ii) at higher saturation, incremental pore-filling is dictated by local pore geometrical characteristics, saturation curves obeying then the Brooks-Corey correlation. According to sessile drop data in the literature, the Cu-Sn system is characterized by relatively small changes in the contact angle with alloy composition (128A degrees-122A degrees), while the metal surface tension changes by more than a factor two over the whole composition range. One would, therefore, expect that the drainage curves be indifferently proportional to the molten metal surface tension or the work of immersion: the present data show that this is indeed verified.
- Published
- 2014
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