Author: "University of Central Florida [Orlando] (UCF)" / Topic: computingmilieux_miscellaneous - Searchworks@Jio Institute Digital Library Search Results

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75 results on '"University of Central Florida [Orlando] (UCF)"'

1. Link between Polycyclic Aromatic Hydrocarbon Size and Aqueous Alteration in Carbonaceous Chondrites Revealed by Laser Mass Spectrometry

Author: Katerina Slavicinska, Dumitru Duca, Dmitrii Egorov, Tirthankar Mitra, Yvain Carpentier, Cristian Focsa, Christopher J. Bennett, Claire Pirim, University of Central Florida [Orlando] (UCF), Laboratoire de Physique des Lasers, Atomes et Molécules - UMR 8523 (PhLAM), Université de Lille-Centre National de la Recherche Scientifique (CNRS), Physique Moléculaire aux Interfaces (PMI), and Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)
Subjects: [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, Atmospheric Science, Space and Planetary Science, Geochemistry and Petrology, [SDE.IE]Environmental Sciences/Environmental Engineering, [PHYS.PHYS.PHYS-CHEM-PH]Physics [physics]/Physics [physics]/Chemical Physics [physics.chem-ph], ComputingMilieux_MISCELLANEOUS
Abstract: International audience
Published: 2022

2. First steps of blue phosphorene growth on Au(1 1 1)

Author: Hanna Enriquez, Hamid Oughaddou, Wei Zhang, Gérald Dujardin, Azzedine Bendounan, Abdelkader Kara, Andrew J. Mayne, Ari P. Seitsonen, Institut des Sciences Moléculaires d'Orsay (ISMO), Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Synchrotron SOLEIL (SSOLEIL), Centre National de la Recherche Scientifique (CNRS), Département de Chimie - ENS Paris, École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), University of Central Florida [Orlando] (UCF), and CY Cergy Paris Université (CY)
Subjects: 010302 applied physics, In situ, Materials science, 02 engineering and technology, 021001 nanoscience & nanotechnology, Epitaxy, 01 natural sciences, law.invention, Phosphorene, chemistry.chemical_compound, chemistry, Electron diffraction, Chemical physics, law, 0103 physical sciences, Density functional theory, [PHYS.COND]Physics [physics]/Condensed Matter [cond-mat], Scanning tunneling microscope, 0210 nano-technology, ComputingMilieux_MISCELLANEOUS, Single layer
Abstract: Blue phosphorene (blue-P) has attracted considerable attention due to its potential applications in optical and electronic devices. However, its synthesis has remained a challenge. Here, we report an experimental investigation of the first steps of blue-P growth on Au(1 1 1) surface by molecular-beam epitaxy. The structure was characterized by in situ low temperature scanning tunneling microscopy, low-energy electron diffraction, combined with density functional theory calculations. We reveal two-dimensional (2D) phosphorus clusters (P-clusters) formed on surface at 150 °C, where the most prevalent structure of P-clusters is composed of triangles with six protrusions. We also demonstrate the transformation of these P-clusters into a single layer of blue-P after post-annealing at 260 °C. Our observation of the growth process is a necessary step for exploring the growth mechanisms further.
Published: 2021

3. Electron-Induced Excitation, Recombination, and Dissociation of Molecular Ions Initiating the Formation of Complex Organic Molecules

Author: Kalyan Chakrabarti, Ousmanou Motapon, I. F. Schneider, Nicolas Douguet, Zsolt J. Mezei, Michel D. Epée Epée, Chi Hong Yuen, Samantha Fonseca dos Santos, Viatcheslav Kokoouline, Mehdi Ayouz, Laboratoire Ondes et Milieux Complexes (LOMC), Centre National de la Recherche Scientifique (CNRS)-Université Le Havre Normandie (ULH), Normandie Université (NU)-Normandie Université (NU), Centre for Atomic Molecular Physics and Quantum Optic [Douala] (CEPAMOQ), Université de Douala, University of Central Florida [Orlando] (UCF), Laboratoire de Génie des Procédés et Matériaux - EA 4038 (LGPM), CentraleSupélec, and Department of Physics [Orlando] (UCF | Physics)
Subjects: Atmospheric Science, Materials science, Atomic Physics (physics.atom-ph), FOS: Physical sciences, 01 natural sciences, Molecular physics, Dissociation (chemistry), Physics - Atomic Physics, Ion, Quantum defect, Geochemistry and Petrology, Physics - Chemical Physics, 0103 physical sciences, Physics::Atomic and Molecular Clusters, Physics::Chemical Physics, 010306 general physics, Instrumentation and Methods for Astrophysics (astro-ph.IM), 010303 astronomy & astrophysics, ComputingMilieux_MISCELLANEOUS, Dissociative recombination, [PHYS]Physics [physics], Chemical Physics (physics.chem-ph), Polyatomic ion, Rotational–vibrational spectroscopy, Diatomic molecule, Physics - Plasma Physics, 3. Good health, Plasma Physics (physics.plasm-ph), Space and Planetary Science, Astrophysics - Instrumentation and Methods for Astrophysics, Excitation
Abstract: We review the study of dissociative recombination and ro-vibrational excitation of diatomic and small polyatomic molecular ions initiating complex organic molecules formation. In particular, we show how Multichannel Quantum Defect Theory (MQDT) and R-matrix methods are used to compute cross sections and rate coefficients for cations in well defined ro-vibrational levels of the ground electronic state, from sub-meV up to few eV collision energies. The most recent MQDT results are compared with either other theoretical data, or with measured data obtained in storage-ring experiments., Comment: 20 pages, 13 figures
Published: 2019

4. Phosphorene: A promising candidate for H2 storage at room temperature

Author: M. Garara, M. Louilidi, Abdelilah Benyoussef, H. Benzidi, M. Lakhal, Omar Mounkachi, A. El Kenz, Hamid Ez-Zahraouy, M. Hamedoun, Abdelkader Kara, LMPHE, Université Mohammed V de Rabat [Agdal], Department of Physics [Orlando] (UCF | Physics), and University of Central Florida [Orlando] (UCF)
Subjects: Materials science, Energy Engineering and Power Technology, 02 engineering and technology, 010402 general chemistry, 7. Clean energy, 01 natural sciences, Hydrogen storage, symbols.namesake, chemistry.chemical_compound, Physisorption, Diffusion (business), ComputingMilieux_MISCELLANEOUS, Renewable Energy, Sustainability and the Environment, 021001 nanoscience & nanotechnology, Condensed Matter Physics, Bond-dissociation energy, Potential energy, 0104 chemical sciences, [CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry, Phosphorene, Fuel Technology, chemistry, Chemical physics, symbols, Density functional theory, van der Waals force, 0210 nano-technology
Abstract: Owing to the existence of periodic channels in phosphorene, this 2D material can be a good candidate for room temperature reversible hydrogen storage. The density functional theory calculations (DFT), including van der Waals interactions (vdW-DF2) coupled with the cooper exchange functional (C09), has been applied to study the potential of phosphorene as a new 2D material for hydrogen storage. Our results show that the adsorption energy (−292 to −277 meV) of H2 on phosphorene is appropriate for storage. The analysis of diffusion pathways between different physisorbed states on phosphorene shows that a single hydrogen molecule diffuses very easily along the open channel (less than 1 meV along the zigzag direction), as compared to 14 meV for diffusion across the channels (along the armchair direction). The potential energy surfaces for the dissociative chemisorption of H2 was computed on highly symmetric sites of phosphorene and the highest activation barrier was found to be 2.77 eV. The very large dissociation energy coupled with a strong physisorption of H2 on phosphorene and facile diffusion, makes this 2D material a promising candidate for H2 storage at room temperature.
Published: 2019

5. Revealing the origin of chemical complexity in extraterrestrial matter by combining multiple characterization techniques: HR-L2MS, TOF-SIMS, and micro-Raman spectroscopy: Invited talk

Author: Pirim, Claire, Dumitru, Duca, Slavicinska, Katerina, Ferrari, Brian, Carpentier, Yvain, Vojkovic, Marin, Chazallon, Bertrand, Focsa, Cristian, Bennett, Christopher J., Laboratoire de Physique des Lasers, Atomes et Molécules - UMR 8523 (PhLAM), Université de Lille-Centre National de la Recherche Scientifique (CNRS), Physique Moléculaire aux Interfaces (PMI), Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), and University of Central Florida [Orlando] (UCF)
Subjects: [CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry, [PHYS]Physics [physics], Astrochemistry -meteorites, [SDU]Sciences of the Universe [physics], Mass spectrometry imaging techniques, Micro-Raman Spectroscopy, Laser desorption ionization mass spectrometry, [PHYS.PHYS.PHYS-CHEM-PH]Physics [physics]/Physics [physics]/Chemical Physics [physics.chem-ph], Secondary ion mass spectrometry SIMS, ComputingMilieux_MISCELLANEOUS
Abstract: International audience
Published: 2021

6. Localized and delocalized bound states of the main isotopologue 48 O 3 and of 18 O-enriched 50 O 3 isotopomers of the ozone molecule near the dissociation threshold

Author: Alexander Alijah, Viatcheslav Kokoouline, David Lapierre, Vladimir G. Tyuterev, Department of Physics [Orlando] (UCF | Physics), University of Central Florida [Orlando] (UCF), Groupe de spectrométrie moléculaire et atmosphérique (GSMA), Université de Reims Champagne-Ardenne (URCA)-Centre National de la Recherche Scientifique (CNRS), QUAMER laboratory , Tomsk State University, and Tomsk State University [Tomsk]
Subjects: Physics, [PHYS]Physics [physics], 010304 chemical physics, General Physics and Astronomy, Rotational–vibrational spectroscopy, 010402 general chemistry, 01 natural sciences, Molecular physics, Spectral line, 0104 chemical sciences, Isotopomers, Delocalized electron, Excited state, 0103 physical sciences, Potential energy surface, Bound state, [CHIM]Chemical Sciences, Isotopologue, Physical and Theoretical Chemistry, ComputingMilieux_MISCELLANEOUS
Abstract: Knowledge of highly excited rovibrational states of ozone isotopologues is of key importance for modelling the dynamics of exchange reactions, for understanding longstanding problems related to isotopic anomalies of the ozone formation, and for analyses of extra-sensitive laser spectral experiments currently in progress. This work is devoted to new theoretical study of high-energy states for the main isotopologue 48O3 = 16O16O16O and for the family of 18O-enriched isotopomers 50O3 = {16O16O18O, 16O18O16O, 18O16O16O} of the ozone molecule considered using a full-symmetry approach. Energies and wave functions of bound states near the dissociation threshold are computed in hyperspherical coordinates accounting for the permutation symmetry of three identical nuclei in 48O3 and of two identical nuclei in 50O3, using the most accurate potential energy surface available now. The obtained vibrational band centers agree with observed ones with the root-mean-squares deviation of about 1 cm-1, making the results appropriate for assignments and analyses of future experimental spectra. The levels delocalized between the three potential wells of ozone isomers are computed and analyzed. The states situated deep in the three (for 48O3) or two (for 50O3) equivalent potential wells have similar energies with negligible splitting. However, the states situated just below the potential barriers separating the wells, are split due to the tunneling between the wells resulting in the splitting of rovibrational sub-bands. We evaluate the amplitudes of the corresponding effects and consider possible perturbations in vibration-rotation bands due to interactions between three potential wells. Theoretical predictions for the splitting of observable band centers are provided for the first time.
Published: 2020

7. RNA-dependent sterol aspartylation in fungi

Author: Yakobov, Nathaniel, Fischer, Frédéric, Mahmoudi, Nassira, Saga, Yusuke, Grube, Christopher, Roy, Hervé, Senger, Bruno, Grob, Guillaume, Tatematsu, Shunsuke, Yokokawa, Daisuke, Mouyna, Isabelle, Latgé, Jean-Paul, Nakajima, Harushi, Kushiro, Tetsuo, Becker, Hubert, Université de Strasbourg (UNISTRA), Génétique moléculaire, génomique, microbiologie (GMGM), Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS), Meiji University [Tokyo], University of Central Florida [Orlando] (UCF), Aspergillus, Institut Pasteur [Paris], This work was supported by the Fondation pour la Recherche Médicale (FRM), to H.D.B. (Grant DBF20160635713), by ‘‘MitoCross’’ Laboratory of Excellence (Grant ANR-10-IDEX-0002-02 to H.D.B.), by the University of Strasbourg (to H.D.B.), by an IDEX from the University of Strasbourg (W17RAT81, to F.F.), the National Center for Scientific Research (H.D.B, B.S., F.F., and N.Y.), and the Meiji University (T.K., Y.S., S.T., D.Y., and H.N.). N.Y. was supported by a fellowship from the French Ministère de l’Enseignement Supérieur et de la Recherche, and N.M. was supported by a postdoctoral fellowship from the FRM (Grant DBF20160635713). H.R. and C.D.G. were supported by NIH Grant 1R21AI144481-01., ANR-10-IDEX-0002,UNISTRA,Par-delà les frontières, l'Université de Strasbourg(2010), and Institut Pasteur [Paris] (IP)
Subjects: Aspartic Acid, ergosterol, Aspergillus fumigatus, [SDV]Life Sciences [q-bio], RNA, Fungal, RNA, Transfer, Amino Acyl, Biological Sciences, Biochemistry, Sterols, [SDE]Environmental Sciences, lipid aminoacylation, Aminoacylation, fungi, aminoacyl-tRNA, DUF2156, [SDV.MP.MYC]Life Sciences [q-bio]/Microbiology and Parasitology/Mycology, ComputingMilieux_MISCELLANEOUS
Abstract: Significance Bacteria are known to add amino acids (aa) to membrane lipids to resist antimicrobials and escape immune responses. This surface lipid aminoacylation process requires diverting aminoacyl-tRNAs from protein synthesis. While widespread in bacteria, no analogous lipid remodeling system had thus far been evidenced in eukaryotes. We uncovered that most fungi tRNA-dependently add aspartate onto ergosterol (ergosteryl-3β-O-l-aspartate [Erg-Asp]), the major sterol found in fungal membranes. Asp addition is catalyzed by an ergosteryl-3β-O-l-aspartate synthase (ErdS) and its removal by a dedicated hydrolase (ErdH). This pathway is conserved across “higher” fungi, including pathogens. Given the central roles of sterols and derivatives in fungi, we propose that the Erg-Asp homeostasis system might impact membrane remodeling, trafficking, antimicrobial resistance, or pathogenicity., Diverting aminoacyl-transfer RNAs (tRNAs) from protein synthesis is a well-known process used by a wide range of bacteria to aminoacylate membrane constituents. By tRNA-dependently adding amino acids to glycerolipids, bacteria change their cell surface properties, which intensifies antimicrobial drug resistance, pathogenicity, and virulence. No equivalent aminoacylated lipids have been uncovered in any eukaryotic species thus far, suggesting that tRNA-dependent lipid remodeling is a process restricted to prokaryotes. We report here the discovery of ergosteryl-3β-O-l-aspartate (Erg-Asp), a conjugated sterol that is produced by the tRNA-dependent addition of aspartate to the 3β-OH group of ergosterol, the major sterol found in fungal membranes. In fact, Erg-Asp exists in the majority of “higher” fungi, including species of biotechnological interest, and, more importantly, in human pathogens like Aspergillus fumigatus. We show that a bifunctional enzyme, ergosteryl-3β-O-l-aspartate synthase (ErdS), is responsible for Erg-Asp synthesis. ErdS corresponds to a unique fusion of an aspartyl-tRNA synthetase—that produces aspartyl-tRNAAsp (Asp-tRNAAsp)—and of a Domain of Unknown Function 2156, which actually transfers aspartate from Asp-tRNAAsp onto ergosterol. We also uncovered that removal of the Asp modifier from Erg-Asp is catalyzed by a second enzyme, ErdH, that is a genuine Erg-Asp hydrolase participating in the turnover of the conjugated sterol in vivo. Phylogenomics highlights that the entire Erg-Asp synthesis/degradation pathway is conserved across “higher” fungi. Given the central roles of sterols and conjugated sterols in fungi, we propose that this tRNA-dependent ergosterol modification and homeostasis system might have broader implications in membrane remodeling, trafficking, antimicrobial resistance, or pathogenicity.
Published: 2020

8. Les fondamentaux de la mécanique quantique sous Python : Rappel de cours et exercices d'application avec programmes inclus

Author: Ayouz, Mehdi, Gillet, Jean-Michel, Janolin, Pierre-Eymeric, Kokoouline, Viatcheslav, Laboratoire de Génie des Procédés et Matériaux (LGPM), CentraleSupélec-Université Paris-Saclay, Laboratoire Structures, Propriétés et Modélisation des solides (SPMS), Institut de Chimie du CNRS (INC)-CentraleSupélec-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), University of Central Florida [Orlando] (UCF), and AYOUZ, MEHDI
Subjects: [PHYS.MPHY]Physics [physics]/Mathematical Physics [math-ph], [PHYS.MPHY] Physics [physics]/Mathematical Physics [math-ph], ComputingMilieux_MISCELLANEOUS
Abstract: International audience
Published: 2020

9. Cross sections for vibronic excitation of CH+ by low-energy electron impact

Author: Viatcheslav Kokoouline, Pietro Cortona, Chi Hong Yuen, Xianwu Jiang, Mehdi Ayouz, University of Central Florida [Orlando] (UCF), Laboratoire Structures, Propriétés et Modélisation des solides (SPMS), Institut de Chimie du CNRS (INC)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Génie des Procédés et Matériaux - EA 4038 (LGPM), CentraleSupélec, and Department of Physics [Orlando] (UCF | Physics)
Subjects: [PHYS]Physics [physics], Physics, Scattering, Electron, 01 natural sciences, 010305 fluids & plasmas, Ion, [SPI]Engineering Sciences [physics], Quantum defect, Matrix (mathematics), symbols.namesake, 0103 physical sciences, Rydberg formula, symbols, Physics::Chemical Physics, Atomic physics, 010306 general physics, ComputingMilieux_MISCELLANEOUS, Excitation, Electron ionization
Abstract: A theoretical approach for the electron-impact vibronic excitation of molecular ions with low-lying excited electronic states is described. In this approach, the fixed-nuclear $R$-matrix method is employed to compute electron-ion scattering matrices in the Born-Oppenheimer approximation. A vibronic frame transformation and the closed-channel elimination procedure in a spirit of molecular quantum defect theory are employed to construct an energy-dependent scattering matrix describing interactions between vibronic channels of the target ion induced by the incident electron. The obtained scattering matrix accounts for Rydberg series of vibronic resonances in the collisional spectrum. The approach is applied to the ${\mathrm{CH}}^{+}$ ion of an astrophysical and technological interest. Cross sections for vibronic excitation for different combinations of initial and final vibronic states are computed. A good agreement between electronic-excitation cross sections, obtained using the quantum defect theory and in a direct $R$-matrix calculation, demonstrates that the present approach provides a reliable tool for determination of vibronic (de-)excitation cross sections for targets with low-energy electronic resonances. Such targets were difficult to treat theoretically using earlier methods.
Published: 2019

10. Episodes of particle ejection from the surface of the active asteroid (101955) Bennu

Author: Christine Hartzell, Guy Libourel, Bashar Rizk, Jian-Yang Li, Daniel J. Scheeres, David Vokrouhlický, C. Drouet d'Aubigny, Derek S. Nelson, Y. Takahashi, Robert A. Jacobson, Michael C. Moreau, Harold C. Connolly, Eric M. Sahr, William F. Bottke, J. A. Seabrook, J. Y. Pelgrift, Leilah K. McCarthy, J. M. Leonard, Ben Rozitis, Kris J. Becker, S. Selznick, J. de León, Josh Emery, Humberto Campins, Javier Licandro, Carl Hergenrother, Erica Jawin, Marina Brozovic, M. Al Asad, A. B. Davis, Florian Thuillet, Jamie Molaro, Pasquale Tricarico, E. J. Lessac-Chenen, Peter G. Antreasian, Jason P. Dworkin, C. K. Maleszewski, Davide Farnocchia, Carina Bennett, Jay W. McMahon, C. Manzoni, C. W. V. Wolner, Steven R. Chesley, P. Michel, Peter Jenniskens, Andrew J. Liounis, J. N. Kidd, Ronald-Louis Ballouz, Dathon Golish, Michael Daly, Daniella DellaGiustina, Daniel P. Glavin, H. L. Roper, William M. Owen, Coralie D. Adam, Brent J. Bos, B. May, Dante S. Lauretta, Laboratoire Kastler Brossel (LKB (Lhomond)), Université Pierre et Marie Curie - Paris 6 (UPMC)-Fédération de recherche du Département de physique de l'Ecole Normale Supérieure - ENS Paris (FRDPENS), Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Dept. of Physics, University of Central Florida [Orlando] (UCF), IHU-LIRYC, Université Bordeaux Segalen - Bordeaux 2-CHU Bordeaux [Bordeaux], Universidad Autonoma de Nuevo Leon [Mexique] (UANL), NASA Goddard Space Flight Center (GSFC), Laboratoire de physique de l'état condensé (LPEC), Centre National de la Recherche Scientifique (CNRS)-Le Mans Université (UM), Dipartimento di Matematica, University of Pisa - Università di Pisa, Université de Washington Seattle, University of Michigan Medical School [Ann Arbor], University of Michigan [Ann Arbor], University of Michigan System-University of Michigan System, Joseph Louis LAGRANGE (LAGRANGE), Université Côte d'Azur (UCA)-Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Instituto de Astrofisica de Canarias (IAC), Lunar and Planetary Laboratory [Tucson] (LPL), University of Arizona, The Open University [Milton Keynes] (OU), Institute of Astronomy, Charles University [Prague] (CU), ANR-15-IDEX-0001,UCA JEDI,Idex UCA JEDI(2015), Fédération de recherche du Département de physique de l'Ecole Normale Supérieure - ENS Paris (FRDPENS), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), University of Central Florida [Orlando], CHU Bordeaux [Bordeaux]-Université Bordeaux Segalen - Bordeaux 2, Le Mans Université (UM)-Centre National de la Recherche Scientifique (CNRS), Centre de Recherches Pétrographiques et Géochimiques (CRPG), Institut national des sciences de l'Univers (INSU - CNRS)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS), Politecnico di Milano [Milan] (POLIMI), Service d'hépato-gastro-entérologie [Hôpital Saint-Louis], Groupe Hospitalier Saint Louis - Lariboisière - Fernand Widal [Paris], Assistance publique - Hôpitaux de Paris (AP-HP) (AP-HP)-Assistance publique - Hôpitaux de Paris (AP-HP) (AP-HP), Laboratoire Avancé de Spectroscopie pour les Intéractions la Réactivité et l'Environnement - UMR 8516 (LASIRe), Ecole Nationale Supérieure de Chimie de Lille (ENSCL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Charles University [Prague], and ANR: 15-IDEX-0001,UCA JEDI,Idex UCA JEDI(2015)
Subjects: Solar System, 010504 meteorology & atmospheric sciences, Origin of water on Earth, Population, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Astrophysics, 01 natural sciences, 0103 physical sciences, education, 010303 astronomy & astrophysics, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, education.field_of_study, Multidisciplinary, Meteoroid, Spacecraft, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], business.industry, 13. Climate action, Asteroid, [SDU]Sciences of the Universe [physics], Solar time, Physics::Space Physics, Astrophysics::Earth and Planetary Astrophysics, business, Orbit determination, Geology
Abstract: INTRODUCTION Active asteroids are small bodies in the Solar System that show ongoing mass loss, such as the ejection of dust, which may be caused by large impacts, volatile release, or rotational acceleration. Studying them informs our understanding of the evolution and destruction of asteroids and the origin of volatile materials such as water on Earth. The OSIRIS-REx (Origins, Spectral Interpretation, Resource Identification, and Security–Regolith Explorer) spacecraft has rendezvoused with the near-Earth asteroid (101955) Bennu. The selection of Bennu as the OSIRIS-REx target was partially based on its spectral similarity to some active asteroids. Observations designed to detect mass loss at Bennu were conducted from Earth and during the spacecraft’s approach, but no signs of asteroid activity were found. However, when the spacecraft entered orbit in January 2019, we serendipitously observed particles in the vicinity of Bennu that had apparently been ejected from its surface. RATIONALE We analyzed the properties and behavior of particles ejected from Bennu to determine the possible mechanisms of ejection and provide understanding of the broader population of active asteroids. Images obtained by the spacecraft indicate multiple discrete ejection events with a range of energies and resultant particle trajectories. We characterized three large ejection events that respectively occurred on 6 January, 19 January, and 11 February 2019. Tracking of individual particles across multiple images by means of optical navigation techniques provided the initial conditions for orbit determination modeling. By combining these approaches, we estimated the locations and times of ejection events and determined initial velocity vectors of particles. We estimated the particle sizes and the minimum energies of the ejection events using a particle albedo and density consistent with observations of Bennu. RESULTS Particles with diameters from 3 m s–1. Estimated energies ranged from 270 mJ for the 6 January event to 8 mJ for the 11 February event. The three events arose from widely separated sites, which do not show any obvious geological distinction from the rest of Bennu’s surface. However, these events all occurred in the late afternoon, between about 15:00 and 18:00 local solar time. In addition to discrete ejection events, we detected a persistent background of particles in the Bennu environment. Some of these background particles have been observed to persist on temporary orbits that last several days—in one case, with a semimajor axis >1 km. The orbital characteristics of these gravitationally bound objects make it possible to determine the ratio of their cross-sectional area to their mass. Combined with their photometric phase functions, this information constrains the parameter space of the particles’ diameters, densities, and albedos. CONCLUSION Plausible mechanisms for the large ejection events include thermal fracturing, volatile release through dehydration of phyllosilicates, and meteoroid impacts. The late-afternoon timing of the events is consistent with any of these mechanisms. Bennu’s boulder geology indicates that thermal fracturing, perhaps enhanced by volatile release, could occur on the asteroid surface. Smaller events, especially those that occur on the night side of Bennu, could be attributable to reimpacting particles. Our observations classify Bennu as an active asteroid. Active asteroids are commonly identified by major mass loss events observable with telescopes, on scales much greater than we observed at Bennu. Our findings indicate that there is a continuum of mass loss event magnitudes among active asteroids.
Published: 2019

11. Cassini UVIS solar occultations by Saturn’s F ring and the detection of collision-produced micron-sized dust

Author: Tracy M. Becker, Nicholas Attree, Joshua Colwell, Larry W. Esposito, Carl D. Murray, Southwest Research Institute [San Antonio] (SwRI), University of Central Florida [Orlando] (UCF), Laboratory for Atmospheric and Space Physics [Boulder] (LASP), University of Colorado [Boulder], Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Queen Mary University of London (QMUL), and Astronomy Unit [London] (AU)
Subjects: Diffraction, Physics, education.field_of_study, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], 010504 meteorology & atmospheric sciences, Population, Astronomy and Astrophysics, Radius, Astrophysics, Light curve, 01 natural sciences, Occultation, [SDU]Sciences of the Universe [physics], 13. Climate action, Space and Planetary Science, Saturn, Physics::Space Physics, 0103 physical sciences, Astrophysics::Earth and Planetary Astrophysics, education, 010303 astronomy & astrophysics, Spectrograph, ComputingMilieux_MISCELLANEOUS, Optical depth, 0105 earth and related environmental sciences
Abstract: We present an analysis of eleven solar occultations by Saturn’s F ring observed by the Ultraviolet Imaging Spectrograph (UVIS) on the Cassini spacecraft. In four of the solar occultations we detect an unambiguous signal from diffracted sunlight that adds to the direct solar signal just before or after the occultations occur. The strongest detection was a 10% increase over the direct signal that was enabled by the accidental misalignment of the instrument’s pointing. We compare the UVIS data with images of the F ring obtained by the Cassini Imaging Science Subsystem (ISS) and find that in each instance of an unambiguous diffraction signature in the UVIS data, the ISS data shows that there was a recent disturbance in that region of the F ring. Similarly, the ISS images show a quiescent region of the F ring for all solar occultations in which no diffraction signature was detected. We therefore conclude that collisions in the F ring produce a population of small ring particles that can produce a detectable diffraction signal immediately interior or exterior to the F ring. The clearest example of this connection comes from the strong detection of diffracted light in the 2007 solar occultation, when the portion of the F ring that occulted the Sun had suffered a large collisional event, likely with S/2004 S 6, several months prior. This collision was observed in a series of ISS images (Murray et al., 2008). Our spectral analysis of the data shows no significant spectral features in the F ring, indicating that the particles must be at least 0.2 µm in radius. We apply a forward model of the solar occultations, accounting for the effects of diffracted light and the attenuated direct solar signal, to model the observed solar occultation light curves. These models constrain the optical depth, radial width, and particle size distribution of the F ring. We find that when the diffraction signature is present, we can best reproduce the occultation data using a particle population with an average effective particle size of less than 300 µm, while occultations without clear diffraction signals are best modeled using a population with an effective particle size larger than 400 µm.
Published: 2018

12. Engineering third-order optical nonlinearities in hybrid chalcogenide-on-silicon platform

Author: Carlos Alonso-Ramos, Eric Cassan, Laurent Vivien, Samuel Serna, Nicolas Dubreuil, Xavier Le Roux, Juejun Hu, Christian Lafforgue, Kathleen Richardson, Hongtao Lin, Centre de Nanosciences et Nanotechnologies (C2N (UMR_9001)), Université Paris-Sud - Paris 11 (UP11)-Centre National de la Recherche Scientifique (CNRS), Massachusetts Institute of Technology (MIT), The College of Optics and Photonics [Orlando] (CREOL), University of Central Florida [Orlando] (UCF), Laboratoire Charles Fabry / Photonique Non Linéaire, Laboratoire Charles Fabry (LCF), Université Paris-Sud - Paris 11 (UP11)-Centre National de la Recherche Scientifique (CNRS)-Institut d'Optique Graduate School (IOGS)-Université Paris-Sud - Paris 11 (UP11)-Centre National de la Recherche Scientifique (CNRS)-Institut d'Optique Graduate School (IOGS), Laboratoire Photonique, Numérique et Nanosciences (LP2N), Université de Bordeaux (UB)-Institut d'Optique Graduate School (IOGS)-Centre National de la Recherche Scientifique (CNRS), LP2N_A5, and LP2N_G2
Subjects: Materials science, Silicon, Chalcogenide, Physics::Optics, chemistry.chemical_element, Chalcogenide glass, 01 natural sciences, 7. Clean energy, law.invention, 010309 optics, chemistry.chemical_compound, Optics, law, 0103 physical sciences, Figure of merit, 010306 general physics, ComputingMilieux_MISCELLANEOUS, [PHYS.PHYS.PHYS-OPTICS]Physics [physics]/Physics [physics]/Optics [physics.optics], Silicon photonics, business.industry, Atomic and Molecular Physics, and Optics, chemistry, Photonics, business, Waveguide, Ultrashort pulse
Abstract: We demonstrated a class of highly nonlinear hybrid waveguide structures based on infiltration of As2S3 chalcogenide glass into silicon slot waveguides. The nonlinear properties of the hybrid waveguides were precisely quantified via a bidirectional top-hat D-scan method, enabling a direct comparison between properties measured using different device geometries. We experimentally demonstrate hybrid As2S3-Si slot waveguides with a two-photon absorption (TPA) figure of merit exceeding 2 at near infrared wavelengths. These waveguides largely satisfy the critical criterion for efficient nonlinear integrated photonics (FOMTPAwg>1), allowing phase shifts greater than π with minimal overall losses. These results pave the way for efficient and robust ultrafast all-optical devices and circuits in large-scale silicon photonics technology.
Published: 2019

13. Theoretical study of electron-induced vibrational excitation of NO 2

Author: Hainan Liu, Mehdi Ayouz, Viatcheslav Kokoouline, Chi Hong Yuen, Samantha Fonseca dos Santos, Pietro Cortona, University of Central Florida [Orlando] (UCF), Laboratoire Structures, Propriétés et Modélisation des solides (SPMS), Institut de Chimie du CNRS (INC)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS), Department of Physics [Orlando] (UCF | Physics), Laboratoire de Génie des Procédés et Matériaux - EA 4038 (LGPM), and CentraleSupélec
Subjects: 010302 applied physics, Physics, [PHYS]Physics [physics], Scattering, Observable, Electron, Condensed Matter Physics, 01 natural sciences, Molecular physics, 010305 fluids & plasmas, Matrix (mathematics), [SPI]Engineering Sciences [physics], Normal mode, 0103 physical sciences, Molecule, Physics::Chemical Physics, Electron ionization, Excitation, ComputingMilieux_MISCELLANEOUS
Abstract: In this study, we compute cross sections for vibrational excitation of NO2 by electron impact. Calculations are performed using a theoretical approach based on a combination of the normal mode approximation for vibrational states of the target molecule, fixed-nuclei electron-NO2 scattering matrices and the vibrational frame transformation employed to evaluate the scattering matrix for vibrational transitions. Thermally-averaged rate coefficients are derived from the obtained cross sections for temperatures in the 10–10000 K interval for excitation of each normal mode of the target molecule. Analytical fits for the rate coefficients for singlets and triplets are provided. In addition, a comprehensive set of calculations are performed for assessing the uncertainty of the present calculations. The uncertainty assessments indicate that the computed observables for vibrational (de-)excitation is reasonable for later use in NO2-containing plasma kinetics modeling.
Published: 2019

14. Cross Sections and Rate Coefficients for Rovibrational Excitation of HeH+ Isotopologues by Electron Impact

Author: Viatcheslav Kokoouline, Mehdi Ayouz, Laboratoire de Génie des Procédés et Matériaux - EA 4038 (LGPM), CentraleSupélec, Department of Physics [Orlando] (UCF | Physics), and University of Central Florida [Orlando] (UCF)
Subjects: Nuclear and High Energy Physics, Tokamak, Helium hydride ion, rovibrational excitation, 01 natural sciences, Ion, law.invention, chemistry.chemical_compound, law, 0103 physical sciences, lcsh:Nuclear and particle physics. Atomic energy. Radioactivity, Isotopologue, 010306 general physics, 010303 astronomy & astrophysics, ComputingMilieux_MISCELLANEOUS, Electron ionization, [PHYS]Physics [physics], Physics, isotopologues, interstellar medium, Plasma, Rotational–vibrational spectroscopy, Condensed Matter Physics, Atomic and Molecular Physics, and Optics, R-matrix, chemistry, quantum-defect theory, helium hydride ion, Computer Science::Programming Languages, lcsh:QC770-798, Atomic physics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Excitation
Abstract: Cross sections and thermal rate coefficients for rotational and vibration excitation of the four stable isotopologues of the 4 HeH + ion by electron impact are presented. The data are calculated using a previously developed theoretical approach. The obtained rate coefficients are fitted to analytical formulas with the 10&ndash, 10,000 K interval of applicability. These present results could be useful in tokamak plasma and astrophysical modeling and can help in the detection of these species in the interstellar medium.
Published: 2019
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15. How is Gaze Influenced by Image Transformations? Dataset and Model

Author: Zhaohui Che, Ali Borji, Patrick Le Callet, Guodong Guo, Xiongkuo Min, Guangtao Zhai, Shanghai Jiao Tong University [Shanghai], University of Central Florida [Orlando] (UCF), The Institute of Automation of the Chinese Academy of Sciences (CASIA), Chinese Academy of Sciences [Beijing] (CAS), Laboratoire des Sciences du Numérique de Nantes (LS2N), IMT Atlantique Bretagne-Pays de la Loire (IMT Atlantique), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT)-Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), Université de Nantes (UN)-Université de Nantes (UN)-École Centrale de Nantes (ECN)-Centre National de la Recherche Scientifique (CNRS), Image Perception Interaction (IPI), Université de Nantes (UN)-Université de Nantes (UN)-École Centrale de Nantes (ECN)-Centre National de la Recherche Scientifique (CNRS)-IMT Atlantique Bretagne-Pays de la Loire (IMT Atlantique), Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), and Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT)
Subjects: FOS: Computer and information sciences, Computer science, Computer Vision and Pattern Recognition (cs.CV), ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION, Computer Science - Computer Vision and Pattern Recognition, 02 engineering and technology, [INFO.INFO-AI]Computer Science [cs]/Artificial Intelligence [cs.AI], Salience (neuroscience), Histogram, 0202 electrical engineering, electronic engineering, information engineering, Code (cryptography), Leverage (statistics), Saliency map, ComputingMilieux_MISCELLANEOUS, business.industry, Stereotype (UML), Eye movement, Pattern recognition, Computer Graphics and Computer-Aided Design, Gaze, Transformation (function), [INFO.INFO-TI]Computer Science [cs]/Image Processing [eess.IV], 020201 artificial intelligence & image processing, Artificial intelligence, business, Software, Generator (mathematics)
Abstract: Data size is the bottleneck for developing deep saliency models, because collecting eye-movement data is very time-consuming and expensive. Most of current studies on human attention and saliency modeling have used high-quality stereotype stimuli. In real world, however, captured images undergo various types of transformations. Can we use these transformations to augment existing saliency datasets? Here, we first create a novel saliency dataset including fixations of 10 observers over 1900 images degraded by 19 types of transformations. Second, by analyzing eye movements, we find that observers look at different locations over transformed versus original images. Third, we utilize the new data over transformed images, called data augmentation transformation (DAT), to train deep saliency models. We find that label-preserving DATs with negligible impact on human gaze boost saliency prediction, whereas some other DATs that severely impact human gaze degrade the performance. These label-preserving valid augmentation transformations provide a solution to enlarge existing saliency datasets. Finally, we introduce a novel saliency model based on generative adversarial networks (dubbed GazeGAN). A modified U-Net is utilized as the generator of the GazeGAN, which combines classic "skip connection" with a novel "center-surround connection" (CSC) module. Our proposed CSC module mitigates trivial artifacts while emphasizing semantic salient regions, and increases model nonlinearity, thus demonstrating better robustness against transformations. Extensive experiments and comparisons indicate that GazeGAN achieves state-of-the-art performance over multiple datasets. We also provide a comprehensive comparison of 22 saliency models on various transformed scenes, which contributes a new robustness benchmark to saliency community. Our code and dataset are available at.
Published: 2019

16. Dissociative recombination of CH2NH2+: a crucial link with interstellar methanimine and Titan ammonia

Author: Viatcheslav Kokoouline, Chi Hong Yuen, I. F. Schneider, Cecilia Ceccarelli, Mehdi Ayouz, Nadia Balucani, School of Animal, Plant & Environmental Sciences, University of the Witwatersrand [Johannesburg] (WITS), Laboratoire Aimé Cotton (LAC), École normale supérieure - Cachan (ENS Cachan)-Université Paris-Sud - Paris 11 (UP11)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Génie des Procédés et Matériaux - EA 4038 (LGPM), CentraleSupélec, Università degli Studi di Perugia (UNIPG), Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Observatoire des Sciences de l'Univers de Grenoble (OSUG), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-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)-Université Grenoble Alpes (UGA)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-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), Laboratoire Ondes et Milieux Complexes (LOMC), Centre National de la Recherche Scientifique (CNRS)-Université Le Havre Normandie (ULH), Normandie Université (NU)-Normandie Université (NU), Centre National d'Études Spatiales [Toulouse] (CNES)-Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS), Technische Physik, Julius-Maximilians-Universität Würzburg [Wurtzbourg, Allemagne] (JMU), Department of Physics [Orlando] (UCF | Physics), University of Central Florida [Orlando] (UCF), Dipartimento di Chimica [Perugia], Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), and Centre National de la Recherche Scientifique (CNRS)-Université Paris-Sud - Paris 11 (UP11)-École normale supérieure - Cachan (ENS Cachan)
Subjects: Astrochemistry, molecular data, Electron, 01 natural sciences, 7. Clean energy, Molecular physics, Ion, Nebulae, symbols.namesake, [SPI]Engineering Sciences [physics], 0103 physical sciences, Atmosphere of Titan, 010303 astronomy & astrophysics, Dissociative recombination, ComputingMilieux_MISCELLANEOUS, Physics, planets and satellites: atmospheres, [PHYS]Physics [physics], 010308 nuclear & particles physics, Star formation, astrochemistry, scattering, Astronomy and Astrophysics, ISM: molecules, molecular processes, 13. Climate action, Space and Planetary Science, astrochimica, symbols, Astrophysics::Earth and Planetary Astrophysics, Titan (rocket family), [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Excitation
Abstract: International audience; Cross sections for dissociative recombination (DR) and vibrational excitation of the CH2NH + 2 ion in collisions with electrons are determined theoretically. The corresponding thermally averaged rate coefficients are computed and fitted to analytical formulas. The obtained DR rate coefficient is significantly smaller than the values recently employed in the photochemical models of the upper atmosphere of Titan, which has an important impact on the models that aim to reproduce the Titan ammonia abundance. On the other hand, the present results support the astrophysical models reproducing the abundance of the methanimine (CH2NH) detected in massive star formation regions. In these models, the CH2NH + 2 DR is a major route of formation of this molecule with a high prebiotic potential.
Published: 2019

17. Changing-look Quasar Candidates: First Results from Follow-up Spectroscopy of Highly Optically Variable Quasars

Author: Amy Lebleu, Matthew J. Graham, Paul J. Green, Nicholas P. Ross, Daniel Stern, Eugene A. Magnier, Nigel Metcalfe, Jessie C. Runnoe, Nick Kaiser, Alastair Bruce, Chelsea L. MacLeod, John J. Ruan, Andy Lawrence, Michael Eracleous, Scott F. Anderson, K. C. Chambers, William S. Burgett, D. Homan, Harvard-Smithsonian Center for Astrophysics (CfA), Harvard University [Cambridge]-Smithsonian Institution, Department of Astronomy [Seattle], University of Washington [Seattle], Institute for Astronomy [Edinburgh] (IfA), University of Edinburgh, Cahill Center for Astronomy and Astrophysics, California Institute of Technology (CALTECH), University of Central Florida [Orlando] (UCF), McGill University = Université McGill [Montréal, Canada], Department of Astronomy, University of Michigan, University of Michigan [Ann Arbor], University of Michigan System-University of Michigan System, Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), Institute for Astronomy, University of Hawai'i at Manoa, Astrophysique, Laboratoire de physique de l'ENS - ENS Paris (LPENS (UMR_8023)), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Université Paris Diderot - Paris 7 (UPD7)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Université Paris Diderot - Paris 7 (UPD7), Smithsonian Institution-Harvard University [Cambridge], University of Central Florida [Orlando], McGill University, Fédération de recherche du Département de physique de l'Ecole Normale Supérieure - ENS Paris (FRDPENS), Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS Paris)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS Paris)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Fédération de recherche du Département de physique de l'Ecole Normale Supérieure - ENS Paris (FRDPENS), and Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS Paris)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS Paris)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Active galactic nucleus, 010504 meteorology & atmospheric sciences, astro-ph.GA, media_common.quotation_subject, Astrophysics::High Energy Astrophysical Phenomena, Population, FOS: Physical sciences, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, Spectral line, Photometry (optics), 0103 physical sciences, education, Spectroscopy, 010303 astronomy & astrophysics, ComputingMilieux_MISCELLANEOUS, Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences, media_common, Physics, education.field_of_study, Astrophysics::Instrumentation and Methods for Astrophysics, Astronomy and Astrophysics, Quasar, Astrophysics - Astrophysics of Galaxies, Galaxy, [PHYS.ASTR.GA]Physics [physics]/Astrophysics [astro-ph]/Galactic Astrophysics [astro-ph.GA], Space and Planetary Science, Sky, Astrophysics of Galaxies (astro-ph.GA)
Abstract: Active galactic nuclei (AGN) that show strong rest-frame optical/UV variability in their blue continuum and broad line emission are classified as "changing-look" AGN, or at higher luminosities changing look quasars (CLQs). These surprisingly large and sometimes rapid transitions challenge accepted models of quasar physics and duty cycles, offer several new avenues for study of quasar host galaxies, and open a wider interpretation of the cause of differences between broad and narrow line AGN. To better characterize extreme quasar variability, we present follow-up spectroscopy as part of a comprehensive search for CLQs across the full SDSS footprint using spectroscopically confirmed quasars from the SDSS DR7 catalog. Our primary selection requires large-amplitude (|\Delta g|>1 mag, |\Delta r|>0.5 mag) variability over any of the available time baselines probed by the SDSS and Pan-STARRS 1 surveys. We employ photometry from the Catalina Sky Survey to verify variability behavior in CLQ candidates where available, and confirm CLQs using optical spectroscopy from the William Herschel, MMT, Magellan, and Palomar telescopes. For our adopted S/N threshold on variability of broad H\beta emission, we find 17 new CLQs, yielding a confirmation rate of >~ 20%. These candidates are at lower Eddington ratio relative to the overall quasar population which supports a disk-wind model for the broad line region. Based on our sample, the CLQ fraction increases from 10% to roughly half as the continuum flux ratio between repeat spectra at 3420 Angstroms increases from 1.5 to 6. We release a catalog of over 200 highly variable candidates to facilitate future CLQ searches., Comment: 26 pages, 9 Figures, 3 Tables. Replaced with accepted version
Published: 2019

18. Cumberland and Rocknest Analog Near-Infrared Reflectance Measurements

Author: Lasue, J., Dehouck, E., Johnson, J. R., Beck, P., Freissinet, C., Graham, H. V., Knudson, C. A., Krämer Ruggiu, L., Wellington, D. F., Bell, J. F., Cannon, K. M., David, G., Forni, O., Gasnault, O., Le Mouélic, S., Mangold, N., Meslin, P. Y., Maurice, S., Wiens, R. C., Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Institut de recherche en astrophysique et planétologie (IRAP), Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Planétologie et Géodynamique [UMR 6112] (LPG), Université d'Angers (UA)-Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), Université de Nantes (UN)-Université de Nantes (UN)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Los Alamos National Laboratory (LANL), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Laboratoire de Géologie de Lyon - Terre, Planètes, Environnement (LGL-TPE), École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut national des sciences de l'Univers (INSU - CNRS)-Université Jean Monnet - Saint-Étienne (UJM)-Centre National de la Recherche Scientifique (CNRS), Johns Hopkins University Applied Physics Laboratory [Laurel, MD] (APL), PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), NASA Goddard Space Flight Center (GSFC), Centre européen de recherche et d'enseignement des géosciences de l'environnement (CEREGE), Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Collège de France (CdF (institution))-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), ASU School of Earth and Space Exploration (SESE), Arizona State University [Tempe] (ASU), University of Central Florida [Orlando] (UCF), Centre National d'Études Spatiales [Toulouse] (CNES)-Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Planétologie et Géodynamique UMR6112 (LPG), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Nantes - Faculté des Sciences et des Techniques, and Université de Nantes (UN)-Université de Nantes (UN)-Université d'Angers (UA)
Subjects: Martian analogs, [SDU.STU.PL]Sciences of the Universe [physics]/Earth Sciences/Planetology, Are dissimilar, Observed in infrared, ComputingMilieux_MISCELLANEOUS
Abstract: International audience; Martian analogs / Observed in infrared / Are dissimilar.
Published: 2019

19. Long-lived monolithic micro-optics for multispectral GRIN applications

Author: lepicard, antoine, Bondu, Flavie, Kang, Myungkoo, Sisken, Laura, Yadav, Anupama, Adamietz, Frédéric, Rodriguez, Vincent, Richardson, Kathleen, Dussauze, Marc, Institut des Sciences Moléculaires (ISM), Université Montesquieu - Bordeaux 4-Université Sciences et Technologies - Bordeaux 1-École Nationale Supérieure de Chimie et de Physique de Bordeaux (ENSCPB)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), University of Central Florida [Orlando] (UCF), School of Materials Science and Engineering, and Clemson University
Subjects: Science, Medicine, [CHIM.INOR]Chemical Sciences/Inorganic chemistry, Article, ComputingMilieux_MISCELLANEOUS
Abstract: The potential for realizing robust, monolithic, near-surface refractive micro-optic elements with long-lived stability is demonstrated in visible and infrared transmitting glasses capable of use in dual band applications. Employing an enhanced understanding of glass chemistry and geometric control of mobile ion migration made possible with electrode patterning, flat, permanent, thermally-poled micro-optic structures have been produced and characterized. Sub-surface (t~5–10 µm) compositional and structural modification during the poling process results in formation of spatially-varying refractive index profiles, exhibiting induced Δn changes up to 5 × 10−2 which remain stable for >15 months. The universality of this approach applied to monolithic vis-near infrared [NIR] oxide and NIR-midwave infrared [MIR] chalcogenide glass materials is demonstrated for the first time. Element size, shape and gradient profile variation possible through pattern design and fabrication is shown to enable a variety of design options not possible using other GRIN process methodologies.
Published: 2018

20. Swept-source optical coherence tomography microsystem with an integrated Mirau interferometer and electrothermal micro-scanner

Author: Philippe Lutz, Nicolas Passilly, Przemyslaw Struk, F E Garcia Ramirez, Christophe Gorecki, Quentin A. A. Tanguy, Sylwester Bargiel, Olivier Gaiffe, Huikai Xie, Franche-Comté Électronique Mécanique, Thermique et Optique - Sciences et Technologies (UMR 6174) (FEMTO-ST), Université de Technologie de Belfort-Montbeliard (UTBM)-Ecole Nationale Supérieure de Mécanique et des Microtechniques (ENSMM)-Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC)-Centre National de la Recherche Scientifique (CNRS), Silesian University of Technology, University of Florida [Gainesville] (UF), AGH University of Science and Technology [Krakow, PL] (AGH UST), and University of Central Florida [Orlando] (UCF)
Subjects: Scanner, Materials science, [INFO.INFO-DS]Computer Science [cs]/Data Structures and Algorithms [cs.DS], 02 engineering and technology, 01 natural sciences, [SPI.MAT]Engineering Sciences [physics]/Materials, [SPI.AUTO]Engineering Sciences [physics]/Automatic, 010309 optics, Optics, Optical coherence tomography, Microsystem, 0103 physical sciences, Miniaturization, medicine, Endomicroscopy, [SPI.NANO]Engineering Sciences [physics]/Micro and nanotechnologies/Microelectronics, ComputingMilieux_MISCELLANEOUS, Microelectromechanical systems, [SPI.ACOU]Engineering Sciences [physics]/Acoustics [physics.class-ph], [PHYS.PHYS.PHYS-OPTICS]Physics [physics]/Physics [physics]/Optics [physics.optics], medicine.diagnostic_test, business.industry, Mirau interferometer, 021001 nanoscience & nanotechnology, Atomic and Molecular Physics, and Optics, 0210 nano-technology, business, Preclinical imaging
Abstract: International audience; In the rapid evolution of gastrointestinal endomicroscopy, optical coherence tomography (OCT) has found many diverse applications. Until recently, the micro-opto–electromechanicalsystems(MOEMS)technologyhasbeenplaying a key role in shaping the miniaturization of these components. We report here, to the best of our knowledge, a novel endoscopic microsystem. It is based on a spectrally tuned MOEMS Mirau micro-interferometer integrated with micro-electro-mechanical systems (MEMS) electro-thermal micro-scanner, operating in the regime of swept-source (SS) OCT imaging. ThisLettervalidatesour initial proof-ofconcept toward the development of such MOEMS probe and thepresentationofexperimentalperformancesoftheresulting SS-OCT microsystem.
Published: 2018

21. First steps of silicene growth on Ag(111)

Author: Abdelkader Kara, Hanna Enriquez, Hamid Oughaddou, Gérald Dujardin, Andrew J. Mayne, Mohamed Rachid Tchalala, Institut des Sciences Moléculaires d'Orsay (ISMO), Université Paris-Sud - Paris 11 (UP11)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Photophysique Moléculaire (PPM), Centre National de la Recherche Scientifique (CNRS)-Université Paris-Sud - Paris 11 (UP11), and University of Central Florida [Orlando] (UCF)
Subjects: [PHYS]Physics [physics], History, Materials science, Condensed matter physics, Silicene, 02 engineering and technology, 021001 nanoscience & nanotechnology, 01 natural sciences, Computer Science Applications, Education, 0103 physical sciences, [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], [PHYS.COND]Physics [physics]/Condensed Matter [cond-mat], 010306 general physics, 0210 nano-technology, ComputingMilieux_MISCELLANEOUS
Abstract: International audience
Published: 2018

22. Helicenes Grafted with 1,1,4,4-Tetracyanobutadiene Moieties: π-Helical Push-Pull Systems with Strong Electronic Circular Dichroism and Two-Photon Absorption

Author: Monika Srebro-Hooper, Thierry Roisnel, Florencio E. Hernandez, Julie Donnelly, Nicolas Vanthuyne, Ludovic Favereau, Raphaël J. Durand, Jochen Autschbach, Jeanne Crassous, Yann Trolez, Romain Bouvier, Vincent Dorcet, Yuly Vesga, Institut des Sciences Chimiques de Rennes (ISCR), Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Uniwersytet Jagielloński w Krakowie = Jagiellonian University (UJ), Institut des Sciences Moléculaires de Marseille (ISM2), Aix Marseille Université (AMU)-École Centrale de Marseille (ECM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), University of Central Florida [Orlando] (UCF), University at Buffalo [SUNY] (SUNY Buffalo), State University of New York (SUNY), CHE-1560881, National Science Foundation, Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), and Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)
Subjects: chiroptical activity, Circular dichroism, 010405 organic chemistry, Chemistry, Organic Chemistry, General Chemistry, 010402 general chemistry, tetracyanobutadiene, 01 natural sciences, Two-photon absorption, Redox, Catalysis, 3. Good health, 0104 chemical sciences, chemistry.chemical_compound, Crystallography, Enantiopure drug, Helicene, Charge Transfer, [CHIM]Chemical Sciences, two-photon absorption, ComputingMilieux_MISCELLANEOUS, helicene, Push pull
Abstract: Enantiopure P- and M-carbo[6]helicenes substituted with one or two tetracyanobutadiene moieties at positions 2 and 15 have been prepared. Grafting of these electron-accepting groups onto the π-helical core resulted in strong charge-transfer effects, which greatly affected the UV/Vis, electronic circular dichroism (ECD), and two-photon absorption (TPA) responses. The ECD signal was found to be reversibly switched by applying a redox stimulus.
Published: 2018

23. Monolithically integrated stretchable photonics

Author: Nanshu Lu, Kathleen Richardson, Anupama Yadav, Hongtao Lin, Carlos Alosno-Ramos, Tian Gu, Lan Li, Yizhong Huang, Jérôme Michon, Junying Li, Juejun Hu, Shutao Qiao, Laurent Vivien, Department of Materials Science & Engineering, University of Delaware [Newark], Massachusetts Institute of Technology (MIT), Groupement de Recherche Eau, Sol, Environnement (GRESE), Université de Limoges (UNILIM), Centre de Nanosciences et de Nanotechnologies [Orsay] (C2N), Université Paris-Sud - Paris 11 (UP11)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), University of Central Florida [Orlando] (UCF), School of Materials Science and Engineering (COMSET), Clemson University, and University of Texas at Austin [Austin]
Subjects: Materials science, stretchable photonics, Physics::Optics, Chalcogenide glass, 02 engineering and technology, Substrate (electronics), Elastomer, Waveguide (optics), Article, law.invention, chalcogenide glass, 020210 optoelectronics & photonics, law, optical resonator, 0202 electrical engineering, electronic engineering, information engineering, ComputingMilieux_MISCELLANEOUS, Coupling, integrated photonics, business.industry, 021001 nanoscience & nanotechnology, Atomic and Molecular Physics, and Optics, Electronic, Optical and Magnetic Materials, Stiffening, Optical cavity, [SPI.OPTI]Engineering Sciences [physics]/Optics / Photonic, Optoelectronics, strain-optical coupling, Photonics, 0210 nano-technology, business
Abstract: Mechanically stretchable photonics provides a new geometric degree of freedom for photonic system design and foresees applications ranging from artificial skins to soft wearable electronics. Here we describe the design and experimental realization of the first single-mode stretchable photonic devices. These devices, made of chalcogenide glass and epoxy polymer materials, are monolithically integrated on elastomer substrates. To impart mechanical stretching capability to devices built using these intrinsically brittle materials, our design strategy involves local substrate stiffening to minimize shape deformation of critical photonic components, and interconnecting optical waveguides assuming a meandering Euler spiral geometry to mitigate radiative optical loss. Devices fabricated following such design can sustain 41% nominal tensile strain and 3000 stretching cycles without measurable degradation in optical performance. In addition, we present a rigorous analytical model to quantitatively predict stress-optical coupling behavior in waveguide devices of arbitrary geometry without using a single fitting parameter.
Published: 2018

24. Mn Diffusion and Reactive Diffusion in Ge: Spintronic Applications

Author: Vinh Le Thanh, Alain Portavoce, Lee Chow, Yauheni Rudzevich, Omar Abbes, Lisa Michez, Christophe Girardeaux, Sylvain Bertaina, Institut des Matériaux, de Microélectronique et des Nanosciences de Provence (IM2NP), Aix Marseille Université (AMU)-Université de Toulon (UTLN)-Centre National de la Recherche Scientifique (CNRS), Centre Interdisciplinaire de Nanoscience de Marseille (CINaM), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS), Department of Physics, University of Central Florida [Orlando] (UCF), and Université de Toulon (UTLN)-Centre National de la Recherche Scientifique (CNRS)-Aix Marseille Université (AMU)
Subjects: Radiation, Materials science, Condensed matter physics, Spintronics, Ferromagnetic material properties, Diffusion, Analytical chemistry, chemistry.chemical_element, Germanium, Magnetic semiconductor, Condensed Matter Physics, Salicide, chemistry, Ferromagnetism, Phase (matter), [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], General Materials Science, ComputingMilieux_MISCELLANEOUS
Abstract: In this paper, we report investigations concerning the fabrication of a diluted Ge (Mn) solution using solid state Mn diffusion, and Mn/Ge reactive diffusion for spintronic applications. The study of Mn diffusion shows that the quasi-totality of the incorporated Mn atoms occupies Ge substitutional sites and probably exhibits two negative elementary charges. The solubility limit of Mn in Ge is comprised between 0.7 and 0.9 % (T  600 °C). We show that substitutional Mn atoms are not ferromagnetic in Ge and consequently that Ge (Mn) diluted magnetic semiconductor can not be produced. Beside the ferromagnetic signal from Mn5Ge3, ferromagnetic signals detected in the samples could be always attributed to surface or bulk Mn-Ge clusters. Furthermore, we show that the CMOS Salicide process is potentially applicable to Mn5Ge3 nanolayer fabrication on Ge for spintronic applications. During Mn (thin-film)/Ge reaction, Mn5Ge3 is the first phase to form, being thermally stable up to 310 °C and exhibiting ferromagnetic properties up to TC ~ 300 K.
Published: 2015

25. Nanoporous Ge thin film production combining Ge sputtering and dopant implantation

Author: Marco Abbarchi, Jacques Perrin Toinin, K. Hoummada, Lee Chow, Sandrine Bernardini, M. Bertoglio, Michael Texier, Alain Portavoce, Institut des Matériaux, de Microélectronique et des Nanosciences de Provence (IM2NP), Aix Marseille Université (AMU)-Université de Toulon (UTLN)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Pierre Aigrain (LPA), Fédération de recherche du Département de physique de l'Ecole Normale Supérieure - ENS Paris (FRDPENS), Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS Paris)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS Paris)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Université de Toulon (UTLN)-Centre National de la Recherche Scientifique (CNRS)-Aix Marseille Université (AMU), Department of Physics, and University of Central Florida [Orlando] (UCF)
Subjects: Materials science, Scanning electron microscope, ION-IMPLANTATION, General Physics and Astronomy, [PHYS.MECA.GEME]Physics [physics]/Mechanics [physics]/Mechanical engineering [physics.class-ph], Nanotechnology, 02 engineering and technology, AMORPHIZATION, lcsh:Chemical technology, 01 natural sciences, lcsh:Technology, Full Research Paper, Sputtering, 0103 physical sciences, General Materials Science, ion implantation, porous material, lcsh:TP1-1185, SI, Electrical and Electronic Engineering, Thin film, lcsh:Science, TEMPERATURE, ComputingMilieux_MISCELLANEOUS, 010302 applied physics, Dopant, business.industry, Nanoporous, lcsh:T, 021001 nanoscience & nanotechnology, POROUS GERMANIUM, lcsh:QC1-999, Nanoscience, germanium, Ion implantation, Transmission electron microscopy, [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], Optoelectronics, MORPHOLOGY, Light emission, lcsh:Q, 0210 nano-technology, business, SILICON NANOCRYSTALS, LIGHT-EMISSION, lcsh:Physics
Abstract: In this work a novel process allowing for the production of nanoporous Ge thin films is presented. This process uses the combination of two techniques: Ge sputtering on SiO2 and dopant ion implantation. The process entails four successive steps: (i) Ge sputtering on SiO2, (ii) implantation preannealing, (iii) high-dose dopant implantation, and (iv) implantation postannealing. Scanning electron microscopy and transmission electron microscopy were used to characterize the morphology of the Ge film at different process steps under different postannealing conditions. For the same postannealing conditions, the Ge film topology was shown to be similar for different implantation doses and different dopants. However, the film topology can be controlled by adjusting the postannealing conditions.
Published: 2015

26. Motuporamine Derivatives as Antimicrobial Agents and Antibiotic Enhancers against Resistant Gram-Negative Bacteria

Author: Marine Blanchet, Aaron Muth, Kristen Skruber, Jean Michel Brunel, Otto Phanstiel, Diane Borselli, Jean-Michel Bolla, Institut de Recherche Biomédicale des Armées [Antenne Marseille] (IRBA), Centre de Recherche en Cancérologie de Marseille (CRCM), Aix Marseille Université (AMU)-Institut Paoli-Calmettes, Fédération nationale des Centres de lutte contre le Cancer (FNCLCC)-Fédération nationale des Centres de lutte contre le Cancer (FNCLCC)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), University of Central Florida [Orlando] (UCF), Bidaut, Ghislain, Centre National de la Recherche Scientifique (CNRS)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut Paoli-Calmettes, and Fédération nationale des Centres de lutte contre le Cancer (FNCLCC)-Fédération nationale des Centres de lutte contre le Cancer (FNCLCC)-Aix Marseille Université (AMU)
Subjects: 0301 basic medicine, [SDV]Life Sciences [q-bio], Antibiotics, antimicrobial agents, [SDV.BBM.BM] Life Sciences [q-bio]/Biochemistry, Molecular Biology/Molecular biology, Biochemistry, antibiotics, Anti-Infective Agents, Drug Resistance, Multiple, Bacterial, Polyamines, ComputingMilieux_MISCELLANEOUS, biology, Full Paper, Enterobacter aerogenes, Full Papers, bacterial resistance, Antimicrobial, 3. Good health, Anti-Bacterial Agents, [SDV] Life Sciences [q-bio], polyamine derivatives, membranes, Molecular Medicine, Efflux, medicine.symptom, Gram-negative bacteria, medicine.drug_class, 030106 microbiology, Microbial Sensitivity Tests, Gram-Positive Bacteria, Microbiology, 03 medical and health sciences, Heterocyclic Compounds, 1-Ring, Antibiotic resistance, Alkaloids, Gram-Negative Bacteria, medicine, [SDV.BBM] Life Sciences [q-bio]/Biochemistry, Molecular Biology, [SDV.BBM]Life Sciences [q-bio]/Biochemistry, Molecular Biology, Molecular Biology, Organic Chemistry, Membrane Transport Proteins, [SDV.BBM.BM]Life Sciences [q-bio]/Biochemistry, Molecular Biology/Molecular biology, biology.organism_classification, 030104 developmental biology, Mechanism of action, motuporamine, Bacteria
Abstract: Dihydromotuporamine C and its derivatives were evaluated for their in vitro antimicrobial activities and antibiotic enhancement properties against Gram‐negative bacteria and clinical isolates. The mechanism of action of one of these derivatives, MOTU‐N44, was investigated against Enterobacter aerogenes by using fluorescent dyes to evaluate outer‐membrane depolarization and permeabilization. Its efficiency correlated with inhibition of dye transport, thus suggesting that these molecules inhibit drug transporters by de‐energization of the efflux pump rather than by direct interaction of the molecule with the pump. This suggests that depowering the efflux pump provides another strategy to address antibiotic resistance.
Published: 2017

27. The OSIRIS-REx target asteroid (101955) Bennu: Constraints on its physical, geological, and dynamical nature from astronomical observations

Author: Beth E. Clark, David Vokrouhlický, Catherine L. Johnson, B. Sutter, Daniel J. Scheeres, Michael C. Nolan, Victoria E. Hamilton, Harold C. Connolly, M. K. Crombie, William F. Bottke, Amy Simon, Scott A. Sandford, M. A. Barucci, Kevin J. Walsh, Richard P. Binzel, Marco Delbo, Jason P. Dworkin, Daniel P. Glavin, Edward A. Cloutis, Dante S. Lauretta, Lindsay P. Keller, Steven R. Chesley, B. C. Clark, Humberto Campins, Patrick Michel, Arlin E. Bartels, Josh Emery, E. B. Bierhaus, Carl Hergenrother, Lunar and Planetary Laboratory [Tucson] (LPL), University of Arizona, Universität Konstanz, Observatoire de Paris, PSL Research University (PSL), Lockheed Martin Space Sciences Laboratory, Lockheed Martin Corporation, Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Southwest Research Institute [Boulder] (SwRI), Department of Physics and Astronomy [Orlando], University of Central Florida [Orlando], Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), Department of Geography [Winnipeg], University of Winnipeg, UNS-CNRS-Observatoire de la Côte d'Azur, NASA Goddard Space Flight Center (GSFC), Stanford Linear Accelerator Center (SLAC), Stanford University [Stanford], Géologie et gestion des ressources minérales et énergétiques (G2R), Université Henri Poincaré - Nancy 1 (UHP)-Institut National Polytechnique de Lorraine (INPL)-Centre de recherches sur la géologie des matières premières minérales et énergétiques (CREGU)-Centre National de la Recherche Scientifique (CNRS), NASA Ames Research Center Cooperative for Research in Earth Science in Technology (ARC-CREST), NASA Ames Research Center (ARC), University of Colorado [Boulder], Jacobs Technology ESCG, Institute of Astronomy, Charles University [Prague], Dept of Archaeology, University of York [York, UK], Université Paris sciences et lettres (PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Department of Physics [Orlando] (UCF | Physics), University of Central Florida [Orlando] (UCF), SLAC National Accelerator Laboratory (SLAC), Stanford University, Observatoire de la Côte d'Azur (OCA), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Charles University [Prague] (CU), Centre National de la Recherche Scientifique (CNRS)-Université de Lille-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), and California Institute of Technology (CALTECH)-NASA
Subjects: Solar System, 010504 meteorology & atmospheric sciences, Venus, Close encounter, 01 natural sciences, Astrobiology, Jupiter, 0103 physical sciences, 010303 astronomy & astrophysics, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, [PHYS]Physics [physics], biology, Potentially hazardous object, Astronomy, biology.organism_classification, Regolith, Geophysics, 13. Climate action, Space and Planetary Science, Asteroid, Physics::Space Physics, Orbit (dynamics), Astrophysics::Earth and Planetary Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Geology
Abstract: We review the results of an extensive campaign to determine the physical, geological, and dynamical properties of asteroid (101955) Bennu. This investigation provides information on the orbit, shape, mass, rotation state, radar response, photometric, spectroscopic, thermal, regolith, and environmental properties of Bennu. We combine these data with cosmochemical and dynamical models to develop a hypothetical timeline for Bennu's formation and evolution. We infer that Bennu is an ancient object that has witnessed over 4.5 Gyr of solar system history. Its chemistry and mineralogy were established within the first 10 Myr of the solar system. It likely originated as a discrete asteroid in the inner Main Belt approximately 0.7–2 Gyr ago as a fragment from the catastrophic disruption of a large (approximately 100-km), carbonaceous asteroid. It was delivered to near-Earth space via a combination of Yarkovsky-induced drift and interaction with giant-planet resonances. During its journey, YORP processes and planetary close encounters modified Bennu's spin state, potentially reshaping and resurfacing the asteroid. We also review work on Bennu's future dynamical evolution and constrain its ultimate fate. It is one of the most Potentially Hazardous Asteroids with an approximately 1-in-2700 chance of impacting the Earth in the late 22nd century. It will most likely end its dynamical life by falling into the Sun. The highest probability for a planetary impact is with Venus, followed by the Earth. There is a chance that Bennu will be ejected from the inner solar system after a close encounter with Jupiter. OSIRIS-REx will return samples from the surface of this intriguing asteroid in September 2023.
Published: 2014

28. The Application of Visual Saliency Models in Objective Image Quality Assessment: A Statistical Evaluation

Author: Wei Zhang, Hantao Liu, Zhou Wang, Ali Borji, Patrick Le Callet, Cardiff University, University of Central Florida [Orlando] (UCF), University of Waterloo [Waterloo], irccyn-ivc, Institut de Recherche en Communications et en Cybernétique de Nantes (IRCCyN), Mines Nantes (Mines Nantes)-École Centrale de Nantes (ECN)-Ecole Polytechnique de l'Université de Nantes (EPUN), Université de Nantes (UN)-Université de Nantes (UN)-PRES Université Nantes Angers Le Mans (UNAM)-Centre National de la Recherche Scientifique (CNRS)-Mines Nantes (Mines Nantes)-École Centrale de Nantes (ECN)-Ecole Polytechnique de l'Université de Nantes (EPUN), and Université de Nantes (UN)-Université de Nantes (UN)-PRES Université Nantes Angers Le Mans (UNAM)-Centre National de la Recherche Scientifique (CNRS)
Subjects: QA75, Computer Networks and Communications, Image quality, Computer science, business.industry, ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION, 020206 networking & telecommunications, 02 engineering and technology, Machine learning, computer.software_genre, Computer Science Applications, Visualization, Artificial Intelligence, Salience (neuroscience), [INFO.INFO-TI]Computer Science [cs]/Image Processing [eess.IV], 0202 electrical engineering, electronic engineering, information engineering, Visual attention, 020201 artificial intelligence & image processing, Artificial intelligence, business, computer, Software, ComputingMilieux_MISCELLANEOUS, Visual saliency
Abstract: Advances in image quality assessment have shown the potential added value of including visual attention aspects in its objective assessment. Numerous models of visual saliency are implemented and integrated in different image quality metrics (IQMs), but the gain in reliability of the resulting IQMs varies to a large extent. The causes and the trends of this variation would be highly beneficial for further improvement of IQMs, but are not fully understood. In this paper, an exhaustive statistical evaluation is conducted to justify the added value of computational saliency in objective image quality assessment, using 20 state-of-the-art saliency models and 12 best-known IQMs. Quantitative results show that the difference in predicting human fixations between saliency models is sufficient to yield a significant difference in performance gain when adding these saliency models to IQMs. However, surprisingly, the extent to which an IQM can profit from adding a saliency model does not appear to have direct relevance to how well this saliency model can predict human fixations. Our statistical analysis provides useful guidance for applying saliency models in IQMs, in terms of the effect of saliency model dependence, IQM dependence, and image distortion dependence. The testbed and software are made publicly available to the research community.
Published: 2016

29. Electron paramagnetic resonance (EPR) studies on the photo-thermo ionization process of photo-thermo-refractive glasses

Author: Hellmut Eckert, Larissa Glebova, José Pedro Donoso Gonzalez, Edgar Dutra Zanotto, Leonid B. Glebov, Cláudio José Magon, José Fernando de Lima, Julien Lumeau, Instituto de Física de São Carlos (IFSC-USP), Universidade de São Paulo = University of São Paulo (USP), Universidade Federal de São Carlos [São Carlos] (UFSCar), RCMO (RCMO), Institut FRESNEL (FRESNEL), Aix Marseille Université (AMU)-École Centrale de Marseille (ECM)-Centre National de la Recherche Scientifique (CNRS)-Aix Marseille Université (AMU)-École Centrale de Marseille (ECM)-Centre National de la Recherche Scientifique (CNRS), The College of Optics and Photonics [Orlando] (CREOL), University of Central Florida [Orlando] (UCF), Universidade de São Paulo (USP), Universidade Federal de Sao Carlos - UFSCar (BRAZIL), and Centre National de la Recherche Scientifique (CNRS)-École Centrale de Marseille (ECM)-Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-École Centrale de Marseille (ECM)-Aix Marseille Université (AMU)
Subjects: Materials science, Analytical chemistry, chemistry.chemical_element, 02 engineering and technology, 01 natural sciences, law.invention, Ion, Electron transfer, law, 0103 physical sciences, Materials Chemistry, Crystallization, Electron paramagnetic resonance, Hyperfine structure, ComputingMilieux_MISCELLANEOUS, 010302 applied physics, Dopant, 021001 nanoscience & nanotechnology, Condensed Matter Physics, Electronic, Optical and Magnetic Materials, Cerium, Unpaired electron, chemistry, Ceramics and Composites, [SPI.OPTI]Engineering Sciences [physics]/Optics / Photonic, [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], Physical chemistry, 0210 nano-technology, RESSONÂNCIA PARAMAGNÉTICA ELETRÔNICA
Abstract: Photo-thermo-refractive (PTR) glass is an optically transparent photosensitive sodium alumino silicate glass, containing NaF and KBr additives, along with cerium, silver, tin and antimony oxide dopants. UV-exposed regions of this glass produce NaF nanocrystals upon heating, giving rise to a permanent localized refractive index change. In this article we examine the initial stages of this crystallization process by continuous-wave and pulsed X-band electron paramagnetic resonance (EPR) spectroscopy. UV exposure of PTR glass produces unpaired electrons whose EPR spectrum is characterized by pronounced peak splitting arising from nuclear magnetic hyperfine interactions with spin-5/2 and spin-7/2 nuclei suggesting close proximity of the unpaired electrons with 121 Sb and 123 Sb nuclei. These results indicate that the Sb 2 O 3 dopant plays a key role in the initial stages of the crystallization mechanism. Upon thermal annealing, leading to the crystallization of NaF, these species disappear, indicating their transient nature. A number of other unpaired electron species identified in the dopant free matrix appear to be unrelated to the crystallization process. These results clearly challenge the classical mechanism proposed decades ago to explain the complex crystallization process of PTR glass. Together with more recent results from optical spectroscopy they support the Nikonorov model involving (1) photoionization of Ce 3 + , (2) transfer of this electron to Sb 5 + species to create a Sb 4 + species, (3) upon annealing electron transfer from Sb 4 + to Ag + ions, producing silver atoms, (4) coalescence of these species into Ag clusters, which (5) serve as nucleation catalysts for NaF nanocrystals.
Published: 2016

30. Proceedings of the Dielectrics for Nanosystems 7: Materials Science, Processing, Reliablity and Manufacturing Symposium

Author: Misra, D, Bauza, D., Chen, Z., Sundaram, K., Obeng, Y., Chikyow, T., Iwai, Hiroshi, New Jersey Institute of Technology [Newark] (NJIT), Institut de Microélectronique, Electromagnétisme et Photonique - Laboratoire d'Hyperfréquences et Caractérisation (IMEP-LAHC ), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), University of Kentucky, University of Central Florida [Orlando] (UCF), National Institute of Standards and Technology [Gaithersburg] (NIST), National Institute for Materials Science (NIMS), and Tokyo Institute of Technology [Tokyo] (TITECH)
Subjects: [SPI.NANO]Engineering Sciences [physics]/Micro and nanotechnologies/Microelectronics, ComputingMilieux_MISCELLANEOUS
Abstract: International audience
Published: 2016

31. Theoretical study of dissociative recombination and vibrational excitation of the ${\mathrm{BF}}_{2}^{+}$ ion by an electron impact

Author: Mehdi Ayouz, Viatcheslav Kokoouline, Khalid Hassouni, János Zsolt Mezei, I. F. Schneider, University of Central Florida [Orlando] (UCF), Laboratoire de Génie des Procédés et Matériaux - EA 4038 (LGPM), CentraleSupélec, Laboratoire Ondes et Milieux Complexes (LOMC), Centre National de la Recherche Scientifique (CNRS)-Université Le Havre Normandie (ULH), and Normandie Université (NU)-Normandie Université (NU)
Subjects: [PHYS]Physics [physics], Scattering, Polyatomic ion, 02 engineering and technology, 021001 nanoscience & nanotechnology, Condensed Matter Physics, 01 natural sciences, Charged particle, Ion, Excited state, 0103 physical sciences, Atomic physics, 010306 general physics, 0210 nano-technology, ComputingMilieux_MISCELLANEOUS, Excitation, Dissociative recombination, Electron ionization
Abstract: Cross-sections for dissociative recombination and electron-impact vibrational excitation of the molecular ion are computed using a theoretical approach that combines the normal modes approximation for the vibrational states of the target ion and use of the UK R-matrix code to evaluate electron–ion scattering matrices for fixed geometries of the ion. Thermally-averaged rate coefficients are obtained from the cross-sections for temperatures in the 10–3000 K range.
Published: 2018

32. Epitaxial Synthesis of Blue Phosphorene

Author: Hamid Oughaddou, Abdelkader Kara, Ari P. Seitsonen, Andrew J. Mayne, Gérald Dujardin, Hanna Enriquez, Azzedine Bendounan, Yongfeng Tong, Wei Zhang, China Aerospace Science and Industry Corporation (CASIC), Synchrotron SOLEIL (SSOLEIL), Centre National de la Recherche Scientifique (CNRS), University of Central Florida [Orlando] (UCF), Physikalisch-Chemisches Institut [Zürich], Universität Zürich [Zürich] = University of Zurich (UZH), Laboratoire de Photophysique Moléculaire (PPM), Centre National de la Recherche Scientifique (CNRS)-Université Paris-Sud - Paris 11 (UP11), Institut des Sciences Moléculaires d'Orsay (ISMO), Université Paris-Sud - Paris 11 (UP11)-Centre National de la Recherche Scientifique (CNRS), Institut des Sciences Moléculaires d’Orsay (ISMO), CNRS, Université Paris-Sud, Université Paris-Saclay, F-91405 Orsay, France, TEMPO Beamline, Synchrotron SOLEIL L’Orme des Merisiers Saint-Aubin B.P.48, Gif-sur-Yvette F-91192, Physics Department, University of Central Florida, and Département de Chimie, École Normale Supérieure
Subjects: Electron mobility, 82D80, Materials science, Photoemission spectroscopy, Band gap, FOS: Physical sciences, 02 engineering and technology, 010402 general chemistry, Epitaxy, 01 natural sciences, Biomaterials, chemistry.chemical_compound, Monolayer, General Materials Science, [PHYS.COND]Physics [physics]/Condensed Matter [cond-mat], ComputingMilieux_MISCELLANEOUS, [PHYS]Physics [physics], Condensed Matter - Materials Science, business.industry, Materials Science (cond-mat.mtrl-sci), General Chemistry, 021001 nanoscience & nanotechnology, 0104 chemical sciences, Phosphorene, chemistry, [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], Optoelectronics, Direct and indirect band gaps, 0210 nano-technology, business, Biotechnology, Molecular beam epitaxy
Abstract: Phosphorene is a new two-dimensional material composed of a single or few atomic layers of black phosphorus. Phosphorene has both an intrinsic tunable direct band gap and high carrier mobility values, which make it suitable for a large variety of optical and electronic devices. However, the synthesis of single-layer phosphorene is a major challenge. The standard procedure to obtain phosphorene is by exfoliation. More recently, the epitaxial growth of single-layer phosphorene on Au(111) has been investigated by molecular beam epitaxy and the obtained structure has been described as a blue-phosphorene sheet. In the present study, large areas of high-quality monolayer phosphorene, with a band gap value at least equal to 0.8 eV, have been synthesized on Au(111). Our experimental investigations, coupled with DFT calculations, give evidence of two distinct phases of blue phosphorene on Au(111), instead of one as previously reported, and their atomic structures have been determined., Comment: This paper reports on the epitaxial synthesis of blue phosphorene
Published: 2018

33. Use of SAPHIR and GMI for intercalibration of polar orbiting passive microwave water vapor sounders

Author: Payne, Vivienne, Wilheit, Thomas, Wang, James, Jones, W., Datta, S., Santos-Garcia, Adrea, Brogniez, Hélène, Clain, Gaëlle, Luo, M., Moncet, Jean-Luc, Mlawer, Eli, Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), Texas A&M University [College Station], Science Systems and Applications, Inc. [Lanham] (SSAI), University of Central Florida [Orlando] (UCF), SPACE - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Atmospheric and Environmental Research, Inc. (AER), and Cardon, Catherine
Subjects: [PHYS.PHYS.PHYS-AO-PH]Physics [physics]/Physics [physics]/Atmospheric and Oceanic Physics [physics.ao-ph], [PHYS.PHYS.PHYS-AO-PH] Physics [physics]/Physics [physics]/Atmospheric and Oceanic Physics [physics.ao-ph], ComputingMilieux_MISCELLANEOUS
Abstract: International audience
Published: 2014

34. Atomic structure of the (2R3x2R3) R 30° of silicene on Ag(111) surface

Author: Enriquez, Hanna, Kara, Abdelkader, Mayne, Andrew, Dujardin, Gérald, Jamgotchian, Haik, Aufray, Bernard, Oughaddou, Hamid, University of Central Florida [Orlando] (UCF), Laboratoire de Photophysique Moléculaire (PPM), Université Paris-Sud - Paris 11 (UP11)-Centre National de la Recherche Scientifique (CNRS), Institut des Sciences Moléculaires d'Orsay (ISMO), Centre Interdisciplinaire de Nanoscience de Marseille (CINaM), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS), and Centre National de la Recherche Scientifique (CNRS)-Université Paris-Sud - Paris 11 (UP11)
Subjects: [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], ComputingMilieux_MISCELLANEOUS
Abstract: International audience
Published: 2014

35. Computation of polarized subsurface BRDF for rendering

Author: Charly Collin, Kadi Bouatouch, Sumanta Pattanaik, Patrick LiKamWa, Université de Rennes (UR), School of Electrical Engineering and Computer Science [Orlando], University of Central Florida [Orlando] (UCF), The College of Optics and Photonics [Orlando] (CREOL), FRVSense (FRVSense), MEDIA ET INTERACTIONS (IRISA-D6), Institut de Recherche en Informatique et Systèmes Aléatoires (IRISA), Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université de Bretagne Sud (UBS)-École normale supérieure - Rennes (ENS Rennes)-Institut National de Recherche en Informatique et en Automatique (Inria)-Télécom Bretagne-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS)-Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université de Bretagne Sud (UBS)-École normale supérieure - Rennes (ENS Rennes)-Institut National de Recherche en Informatique et en Automatique (Inria)-Télécom Bretagne-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche en Informatique et Systèmes Aléatoires (IRISA), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université de Bretagne Sud (UBS)-École normale supérieure - Rennes (ENS Rennes)-Institut National de Recherche en Informatique et en Automatique (Inria)-Télécom Bretagne-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS), Cozot, Rémi, Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES), CentraleSupélec-Télécom Bretagne-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut National de Recherche en Informatique et en Automatique (Inria)-École normale supérieure - Rennes (ENS Rennes)-Université de Bretagne Sud (UBS)-Centre National de la Recherche Scientifique (CNRS)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-CentraleSupélec-Télécom Bretagne-Université de Rennes 1 (UR1), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-Institut de Recherche en Informatique et Systèmes Aléatoires (IRISA), and Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)
Subjects: 010504 meteorology & atmospheric sciences, Computer science, business.industry, Computation, Polarimetry, [INFO.INFO-GR] Computer Science [cs]/Graphics [cs.GR], Subsurface scattering, Polarization (waves), 01 natural sciences, [INFO.INFO-GR]Computer Science [cs]/Graphics [cs.GR], Optics, 0103 physical sciences, Radiance, Radiative transfer, Degree of polarization, Bidirectional reflectance distribution function, business, 010303 astronomy & astrophysics, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences
Abstract: Interest in polarization properties of the rendered materials is growing, but so far discussions on polarization have been restricted only to surface reflection, and the reflection due to subsurface scattering is assumed to be unpolarized. Findings from other field (e.g. optics and atmospheric science) show that volumetric interaction of light can contribute to polarization. So we investigated the polarized nature of the radiance field due to subsurface scattering as a function of the thickness of the material layer for various types of materials. Though our computations shows negligible polarization for material layers of high thickness, thin layered materials show significant degree of polarization. That means polarization cannot be ignored for subsurface component of reflection from painted surfaces (particularly painted metal surfaces) or from coated materials. In this paper we employ the vector radiative transfer equation (VRTE), which is the polarized version of the radiative transfer equation inside the material. We use a discrete ordinate based method to solve the VRTE and compute the polarized radiance field at the surface of the material layer. We generate the polarimetric BRDF from the solutions of the VRTE for incident irradiance with different polarizations. We validate our VRTE solution against a benchmark and demonstrate our results through renderings using the computed BRDF.
Published: 2014

36. Impact of temperature on performance in two species of South African dwarf chameleon, Bradypodion pumilum and B. occidentale

Author: Perrenoud, M., Decamps, T., Abdala, V., Manzano, A., Pouydebat, E., Houssaye, Alexandra, Böhme, Wolfgang, Konow, Nicolai, Krijestorac, Belma, Sanford, Christopher, Segall, M., Tolley, K., Vanhooydonck, B., Measey, G., Herrel, Anthony, Rathgen-Forschungslabor, Staatliche Museen zu Berlin-Stiftung Preußischer KulturbesitzBerlin, Delft University of Technology (TU Delft), Laboratoire de Biomodélisation et Ingénierie des Handicaps - EA 4322 (HANDIBIO), Université de Toulon (UTLN), Mécanismes adaptatifs : des organismes aux communautés, Muséum national d'Histoire naturelle (MNHN)-Centre National de la Recherche Scientifique (CNRS), Zoologische Forschungsmuseum Alexander Koenig (ZFMK), Center for Research and Education in Optics and Lasers (CREOL), and University of Central Florida [Orlando] (UCF)-School of Optics
Subjects: Male, 0106 biological sciences, Physiology, [SDV]Life Sciences [q-bio], Climate change, Aquatic Science, Biology, 010603 evolutionary biology, 01 natural sciences, Acclimatization, Bite Force, South Africa, 03 medical and health sciences, Species Specificity, Animals, Molecular Biology, Bradypodion pumilum, Ecology, Evolution, Behavior and Systematics, ComputingMilieux_MISCELLANEOUS, 030304 developmental biology, Bradypodion, 0303 health sciences, Ecology, [SDV.BA]Life Sciences [q-bio]/Animal biology, Temperature, Lizards, biology.organism_classification, 13. Climate action, Insect Science, Ectotherm, Threatened species, Trait, Female, Animal Science and Zoology, Human medicine, Adaptation
Abstract: Summary Temperature is an extrinsic factor which influences reptile behavior given that their physiology is dependent on environmental temperature. Understanding the impact of temperature on performance traits is important as it may affect the ecology and fitness of ectothermic animals such as reptiles. Here we examine the temperature dependence of performance in two species of South African Dwarf chameleon (Bradypodion), a semi-arid and a mesic adapted species. Ecologically relevant performance traits were tested at different temperatures to evaluate their thermal dependence and temperature-performance breadths for 80% and 90% of each performance trait were calculated. Our results show distinct differences in the thermal dependence of speed versus force-related performance traits. Moreover, our results show that the semi-arid species is better adapted to higher temperatures and as such has better chances to cope with the predicted increases in temperature. The mesic-adapted species seems to be more sensitive to an increase in temperature and could therefore potentially be threatened by predicted future climate change. However, further studies investigating the potential for acclimation in chameleons are needed to better understand how animals may respond to predicted future climate change.
Published: 2013

37. Plasmon assisted thermal modulation in nanoparticles

Author: R. H. Farahi, Ali Passian, Laurene Tetard, Thomas Thundat, Stefan Enoch, Aude L. Lereu, Institut FRESNEL (FRESNEL), Centre National de la Recherche Scientifique (CNRS)-École Centrale de Marseille (ECM)-Aix Marseille Université (AMU), Oak Ridge National Laboratory [Oak Ridge] (ORNL), UT-Battelle, LLC, Nanoscience Technology Center [Orlando] (UCF | NTC), University of Central Florida [Orlando] (UCF), CONCEPT (CONCEPT), Aix Marseille Université (AMU)-École Centrale de Marseille (ECM)-Centre National de la Recherche Scientifique (CNRS)-Aix Marseille Université (AMU)-École Centrale de Marseille (ECM)-Centre National de la Recherche Scientifique (CNRS), Aix Marseille Université (AMU)-École Centrale de Marseille (ECM)-Centre National de la Recherche Scientifique (CNRS), University of Alberta, and Centre National de la Recherche Scientifique (CNRS)-École Centrale de Marseille (ECM)-Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-École Centrale de Marseille (ECM)-Aix Marseille Université (AMU)
Subjects: Materials science, Hot Temperature, Nanomaterials, Physics::Optics, Nanoparticle, Metal Nanoparticles, Nanotechnology, 02 engineering and technology, Modulators, 7. Clean energy, 01 natural sciences, Thermal effects, [SPI]Engineering Sciences [physics], 0103 physical sciences, Computer Simulation, Thin film, 010306 general physics, Plasmon, ComputingMilieux_MISCELLANEOUS, [PHYS]Physics [physics], Surface plasmon, Surface Plasmon Resonance, 021001 nanoscience & nanotechnology, Atomic and Molecular Physics, and Optics, (250.5403) Plasmonics, (230.4110) Modulators, (120.6810) Thermal effects, (160.4236) Nanomaterials, [SPI.ELEC]Engineering Sciences [physics]/Electromagnetism, Nanolithography, Models, Chemical, Modulation, Heat generation, [SPI.OPTI]Engineering Sciences [physics]/Optics / Photonic, Plasmonics, Gold, 0210 nano-technology
Abstract: International audience; Single-particle interactions hold the promise of nanometer-scaledevices in areas such as data communications and storage, nanolithography,waveguides, renewable energy and therapeutics. We propose that thecollective electronic properties possessed by noble metal nanoparticlesmay be exploited for device actuation via the unapparent mechanism ofplasmon-assisted heat generation and flux. The temperature dependence ofthe dielectric function and the thermal transport properties of the particlesplay the central role in the feasibility of the thermally-actuated system,however the behavior of these thermoplasmonic processes is unclear. Weexperimentally and computationally analyzed modulation via thermoplasmonicprocesses on a test system of gold (Au) nano-islands. Modulation andenergy transport in discontinuous domains exhibited quantitatively differentcharacteristics compared to thin films. The results have implications for allsurface plasmon based nano-devices where inevitable small-scale thermalprocesses are present.
Published: 2013

38. Green's function solution to subsurface light transport for BRDF computation

Author: Ke Chen, Sumanta Pattanaik, Ajit Hakke-Patil, Charly Collin, Kadi Bouatouch, Université de Rennes (UR), School of Electrical Engineering and Computer Science [Orlando], University of Central Florida [Orlando] (UCF), FRVSense (FRVSense), MEDIA ET INTERACTIONS (IRISA-D6), Institut de Recherche en Informatique et Systèmes Aléatoires (IRISA), Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université de Bretagne Sud (UBS)-École normale supérieure - Rennes (ENS Rennes)-Institut National de Recherche en Informatique et en Automatique (Inria)-Télécom Bretagne-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS)-Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université de Bretagne Sud (UBS)-École normale supérieure - Rennes (ENS Rennes)-Institut National de Recherche en Informatique et en Automatique (Inria)-Télécom Bretagne-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche en Informatique et Systèmes Aléatoires (IRISA), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université de Bretagne Sud (UBS)-École normale supérieure - Rennes (ENS Rennes)-Institut National de Recherche en Informatique et en Automatique (Inria)-Télécom Bretagne-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES), CentraleSupélec-Télécom Bretagne-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut National de Recherche en Informatique et en Automatique (Inria)-École normale supérieure - Rennes (ENS Rennes)-Université de Bretagne Sud (UBS)-Centre National de la Recherche Scientifique (CNRS)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-CentraleSupélec-Télécom Bretagne-Université de Rennes 1 (UR1), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-Institut de Recherche en Informatique et Systèmes Aléatoires (IRISA), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA), and Cozot, Rémi
Subjects: 010504 meteorology & atmospheric sciences, Scattering, Computer science, Computation, [INFO.INFO-GR] Computer Science [cs]/Graphics [cs.GR], Subsurface scattering, Function (mathematics), Solver, 01 natural sciences, [INFO.INFO-GR]Computer Science [cs]/Graphics [cs.GR], symbols.namesake, Computer graphics (images), Green's function, 0103 physical sciences, symbols, Bidirectional reflectance distribution function, Convection–diffusion equation, 010303 astronomy & astrophysics, Algorithm, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences
Abstract: This paper presents an accurate method to compute the bidirectional reflectance distribution function (BRDF) due to subsurface scattering inside the material of the objects. This computation requires iterating over the different lighting directions, and solving the integro-differential equation of light transport (scattering and absorption). Solving the light transport equation is expensive, and solving it independently for different directions adds even further to the expense. However most of the computations are very similar between directions. We make use of Green's function of the transport problem to have a better separation between computations that are independent of incident directions from those that are dependent. This allows us to avoid as much repetition in the computations as possible, thus gives us a faster BRDF computation method without any loss of accuracy. We validate our method against a standard light transport solver and use it to compute BRDF for a variety of materials.
Published: 2013

39. Visibility-driven progressive volume photon tracing

Author: Charly Collin, Kadi Bouatouch, Mickaël Ribardière, Rémi Cozot, Adrien Gruson, Sumanta Pattanaik, Université de Rennes (UR), SIC (XLIM-SIC), Université de Poitiers-XLIM (XLIM), Université de Limoges (UNILIM)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM)-Centre National de la Recherche Scientifique (CNRS), FRVSense (FRVSense), MEDIA ET INTERACTIONS (IRISA-D6), Institut de Recherche en Informatique et Systèmes Aléatoires (IRISA), Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université de Bretagne Sud (UBS)-École normale supérieure - Rennes (ENS Rennes)-Institut National de Recherche en Informatique et en Automatique (Inria)-Télécom Bretagne-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS)-Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université de Bretagne Sud (UBS)-École normale supérieure - Rennes (ENS Rennes)-Institut National de Recherche en Informatique et en Automatique (Inria)-Télécom Bretagne-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche en Informatique et Systèmes Aléatoires (IRISA), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université de Bretagne Sud (UBS)-École normale supérieure - Rennes (ENS Rennes)-Institut National de Recherche en Informatique et en Automatique (Inria)-Télécom Bretagne-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS), School of Electrical Engineering and Computer Science [Orlando], University of Central Florida [Orlando] (UCF), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES), CentraleSupélec-Télécom Bretagne-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut National de Recherche en Informatique et en Automatique (Inria)-École normale supérieure - Rennes (ENS Rennes)-Université de Bretagne Sud (UBS)-Centre National de la Recherche Scientifique (CNRS)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-CentraleSupélec-Télécom Bretagne-Université de Rennes 1 (UR1), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-Institut de Recherche en Informatique et Systèmes Aléatoires (IRISA), and Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)
Subjects: Photon, Global illumination, Computer science, ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION, 020207 software engineering, Volume rendering, 02 engineering and technology, Data structure, Computer Graphics and Computer-Aided Design, [INFO.INFO-GR]Computer Science [cs]/Graphics [cs.GR], Rendering (computer graphics), Computer graphics, Computer graphics (images), 0202 electrical engineering, electronic engineering, information engineering, Preprocessor, 020201 artificial intelligence & image processing, Computer Vision and Pattern Recognition, Specular reflection, Software, ComputingMilieux_MISCELLANEOUS, ComputingMethodologies_COMPUTERGRAPHICS
Abstract: International audience; In this paper, we present a novel approach to progressive photon-based volume rendering techniques. By making use of two Kd-trees (built in a preprocessing step) to store view beams (primary rays intersecting the medium) and visible points, our method allows to handle scenes with specular and refractive objects as well as homogeneous and heterogeneous participating media and does not require the storage of photon maps, which solves the memory management issue. These data structures are used to drive the photon shooting process by considering the photon visibility as an importance function (similarly to Hachisuka and Jensen in ACM Trans. Graph. 30(5):114:1–114:11, 2011) for scenes containing participating media. Finally, we demonstrate that our method can be easily combined with the most recent particle tracing approaches such as the one presented in Jarosz et al. (ACM Trans. Graph., vol. 30(6), 2011).
Published: 2013

40. Nanometric-Size Effect upon Diffusion and Reaction in Semiconductors: Experimental and Theoretical Investigations

Author: Jean Bernardini, Guy Tréglia, Lee Chow, Christophe Girardeaux, Alain Portavoce, Dominique Mangelinck, Institut des Matériaux, de Microélectronique et des Nanosciences de Provence (IM2NP), Aix Marseille Université (AMU)-Université de Toulon (UTLN)-Centre National de la Recherche Scientifique (CNRS), Centre Interdisciplinaire de Nanoscience de Marseille (CINaM), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS), Department of Physics, University of Central Florida [Orlando] (UCF), Université de Toulon (UTLN)-Centre National de la Recherche Scientifique (CNRS)-Aix Marseille Université (AMU), Girardeaux, Christophe, and Cinam, Hal
Subjects: 010302 applied physics, Radiation, Materials science, Nucleation, Lattice diffusion coefficient, Nanotechnology, 02 engineering and technology, 021001 nanoscience & nanotechnology, Condensed Matter Physics, 01 natural sciences, Atomic units, Nanocrystalline material, [PHYS.COND.CM-MS] Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], Atomic diffusion, Chemical physics, 0103 physical sciences, [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], General Materials Science, Grain boundary, Diffusion (business), Thin film, 0210 nano-technology, ComputingMilieux_MISCELLANEOUS
Abstract: The use of nanometric size materials as embedded clusters, nanometric films, nanocrystalline layers and nanostructures is steadily increasing in industrial processes aiming to produce materials and devices. This is especially true in today Si-based microelectronics with transistors made of a multitude of different thin film materials (B-, As-, and P-doped Si, NiSi (Pt), poly-Si, W, TiOx, LaO, SiO2, Al, HfO2), and exhibiting a characteristic lateral size of 32-22 nm. Size reduction leads to an increasing role of surfaces and interfaces, as well as stress and nanoscale effects upon important phenomena driving fabrication processes, such as atomic diffusion, phase nucleation, phase growth, and coarsening. Consequently, nanotechnology related to Material Science requires an investigation at the nanometric (or atomic) scale of elementary physical phenomena that are well-known at the microscopic scale. This paper is focused on nanosize effects upon diffusion in Si and Si reactive diffusion. We present recent results showing that the kinetic of lattice diffusion is enhanced in semiconductor nanometric (nano) grains, while grain boundary (GB) diffusion is not changed in nanoGBs. It is also shown that diffusion in triple-junction (TJ) is several orders of magnitude faster than GB diffusion, and that its effect cannot be neglected in nanocrystalline (nc) layers made of 40 nm-wide grains. Experimental results concerning Si sub-nanometric film reaction on Ni (111) substrate are also presented and compared to theoretical results giving new prospects concerning nanosize effects on reactive diffusion at the atomic scale.
Published: 2012

41. Effect of Replacement of As by Ge and Sb on the Photo-Response under Near Infrared Femtosecond Laser Irradiation in As-based Sulfide Glasses

Author: Le Rouge, A. (A), El Hamzaoui, H. (H.), CAPOEN, B. (Bruno), Bernard, R. (R.), Cristini-Robbe, O. (O.), Martinelli, G. (G), Cassagne, C. (C.), Bouazaoui, M. (M.), Bigot, L. (L.), David Musgraves, J. (J.), Carlie, N. (Nathan), Petit, L. (Laeticia), Boudebs, G. (Georges), Choi, J. (Jiyeon), Richardson, M. (Martin), Richardson, K. (Kathleen), Laboratoire de Physique des Lasers, Atomes et Molécules - UMR 8523 [PhLAM], Centre d'Etudes et de Recherches Lasers et Applications [CERLA], Institut de Recherche en Génie Civil et Mécanique [GeM], Laboratoire de Photonique d'Angers [LPHIA], The College of Optics and Photonics [Orlando] [CREOL], School of Materials Science and Engineering, Clemson University, nLIGHT Corporation, School of Materials Science and Engineering (COMSET), Laboratoire de Photonique d'Angers (LPHIA), Université d'Angers (UA), The College of Optics and Photonics [Orlando] (CREOL), University of Central Florida [Orlando] (UCF), Townes Laser Institute, the College of Optics and Photonics (TLI-CREOL), Laboratoire de Physique des Lasers, Atomes et Molécules - UMR 8523 (PhLAM), Université de Lille-Centre National de la Recherche Scientifique (CNRS), Centre d'Etudes et de Recherches Lasers et Applications (CERLA), Université de Lille, Sciences et Technologies, Institut de Recherche en Génie Civil et Mécanique (GeM), Université de Nantes - Faculté des Sciences et des Techniques, Université de Nantes (UN)-Université de Nantes (UN)-École Centrale de Nantes (ECN)-Centre National de la Recherche Scientifique (CNRS), and University of Central Florida [Orlando]
Subjects: Materials science, genetic structures, Sulfide, Analytical chemistry, 02 engineering and technology, Diffraction efficiency, 01 natural sciences, law.invention, 010309 optics, Optics, law, Phase (matter), 0103 physical sciences, General Materials Science, Irradiation, ComputingMilieux_MISCELLANEOUS, chemistry.chemical_classification, [PHYS.PHYS.PHYS-OPTICS]Physics [physics]/Physics [physics]/Optics [physics.optics], business.industry, 021001 nanoscience & nanotechnology, Laser, chemistry, Absorption band, Femtosecond, sense organs, 0210 nano-technology, business, Refractive index
Abstract: International audience; Bulk glasses having the compositions As 42 S 58 , As 36 Sb 6 S 58 , and As 36 Ge 6 S 58 have been irradiated at 800 nm using a femtosecond-pulsed laser to determine the relationship between composition and photo-response. Localized variation in the glass volume (photo-expansion) has been determined through interferometric measurements of surface exposures, whereas induced refractive index change (photo-darkening) was determined from the diffraction efficiency of subsurface direct-written phase gratings. To understand the compositional dependence of the photo-response, the linear and nonlinear optical properties and structure of the unexposed glasses have been compared. The ablation threshold is shown to be controlled by variation of the nonlinear absorption, related to shifts of the absorption band gap with exchange of As by Ge or Sb. Changes in the unexposed network structure show that partial replacement of As by Ge or Sb induces an increased number of As–As bonding defects in the glass, particularly in the form of As 4 S 4 molecular units which become polymerized into the network, impacting the photo-modification process. The Ge was found to induce an increase in the ablation threshold, and enhance both photo-darkening and photo-expansion effects, whereas Sb was shown to decrease ablation threshold and inhibit photo-darkening while enhancing photo-expansion.
Published: 2011

42. Femtosecond laser induced photochemistry in materials tailored with photosensitive agents

Author: Arnaud Royon, Martin Richardson, Gautier Papon, Yannick Petit, Lionel Canioni, Laboratoire Ondes et Matière d'Aquitaine (LOMA), Université de Bordeaux (UB)-Centre National de la Recherche Scientifique (CNRS), Group of Applied Physics [Geneva] (GAP), University of Geneva [Switzerland], Ashima Research, Institut de Chimie de la Matière Condensée de Bordeaux (ICMCB), Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut Polytechnique de Bordeaux-Université de Bordeaux (UB), The College of Optics and Photonics [Orlando] (CREOL), University of Central Florida [Orlando] (UCF), and Conseil Régional d'Aquitaine, the GIS AMA and the ANR (grant # BLAN 946 04)
Subjects: Materials science, Optical property, Nanoparticle, Physics::Optics, 02 engineering and technology, Photochemistry, 01 natural sciences, law.invention, Nanoclusters, (320.2250) Femtosecond phenomena, 010309 optics, law, Optical materials, 0103 physical sciences, ComputingMilieux_MISCELLANEOUS, chemistry.chemical_classification, [PHYS]Physics [physics], business.industry, (140.3450) Laser induced chemistry, Polymer, 021001 nanoscience & nanotechnology, Laser, Electronic, Optical and Magnetic Materials, (140.3390) Laser materials processing, OCIS, chemistry, Femtosecond, Optoelectronics, (160.4670) Optical materials, 0210 nano-technology, business
Abstract: International audience; This article deals with the recent advances in photochemistry in optical materials induced by femtosecond laser pulses. The field of investigation of this paper is limited to bulk solid isotropic transparent materials (glasses and polymers), specifically tailored with photoactive agents. The formation mechanisms of laser-induced color centers, nanoclusters, nanoparticles and nanocrystallites are reviewed and argued, in particular the influence of the temperature during or after the laser irradiation. The relation between the photo-induced structures and the optical property modifications are discussed, as well as some applications.
Published: 2011

43. Disentangling stand and environmental correlates of aboveground biomass in Amazonian forests

Author: Baraloto, Christopher, Rabaud, Suzanne, Molto, Quentin, Blanc, Lilian, FORTUNEL, Claire, Hérault, Bruno, DÁVILA, NALLARETT, Mesones, Italo, Rios, Marcos, Valderrama, Elvis, Fine, Paul V. A., Ecologie des forêts de Guyane (ECOFOG), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Institut National de la Recherche Agronomique (INRA)-Université des Antilles et de la Guyane (UAG)-AgroParisTech-Centre National de la Recherche Scientifique (CNRS), Department of Integrative Biology [Berkeley] (IB), University of California [Berkeley], University of California-University of California, Universidad Nacional de la Amazonía Peruana [Loreto, Perou] (UNAP), Universidad nacional de la amazonia peruana, Départment of biology, University of Central Florida [Orlando] (UCF), Department of biology, University of Florida [Gainesville] (UF), Université des Antilles et de la Guyane (UAG), Botany Graduate Program, Instituto Nacional de Pesquisas da Amazônia (INPA), Department of integrative biology, University of California, and Departement of integrative biology
Subjects: Carbone, P40 - Météorologie et climatologie, REDD, [SDE.MCG]Environmental Sciences/Global Changes, Climate, [SDV]Life Sciences [q-bio], Stockage, F62 - Physiologie végétale - Croissance et développement, Forêt inondée, Facteur climatique, Flooded forest, K01 - Foresterie - Considérations générales, Biomasse, Peru, Tropical rainforest, Propriété physicochimique du sol, Forêt tropicale humide, White sand forest, ComputingMilieux_MISCELLANEOUS, [SDV.EE]Life Sciences [q-bio]/Ecology, environment, U10 - Informatique, mathématiques et statistiques, White-sand forest, P35 - Fertilité du sol, Wood specific gravity, Facteur édaphique, French Guiana, Carbon stocks, Gravité, Soil properties, Modèle mathématique, forest structure
Abstract: Tropical forests contain an important proportion of the carbon stored in terrestrial vegetation, but estimated aboveground biomass (AGB) in tropical forests varies two-fold, with little consensus on the relative importance of climate, soil and forest structure in explaining spatial patterns. Here, we present analyses from a plot network designed to examine differences among contrasting forest habitats (terra firme, seasonally flooded, and white-sand forests) that span the gradient of climate and soil conditions of the Amazon basin. We installed 0.5-ha plots in 74 sites representing the three lowland forest habitats in both Loreto, Peru and French Guiana, and we integrated data describing climate, soil physical and chemical characteristics and stand variables, including local measures of wood specific gravity (WSG). We use a hierarchical model to separate the contributions of stand variables from climate and soil variables in explaining spatial variation in AGB. AGB differed among both habitats and regions, varying from 78 Mg ha−1 in white-sand forest in Peru to 605 Mg ha−1 in terra firme clay forest of French Guiana. Stand variables including tree size and basal area, and to a lesser extent WSG, were strong predictors of spatial variation in AGB. In contrast, soil and climate variables explained little overall variation in AGB, though they did co-vary to a limited extent with stand parameters that explained AGB. Our results suggest that positive feedbacks in forest structure and turnover control AGB in Amazonian forests, with richer soils (Peruvian terra firme and all seasonally flooded habitats) supporting smaller trees with lower wood density and moderate soils (French Guianan terra firme) supporting many larger trees with high wood density. The weak direct relationships we observed between soil and climate variables and AGB suggest that the most appropriate approaches to landscape scale modeling of AGB in the Amazon would be based on remote sensing methods to map stand structure.
Published: 2011

44. Proceedings of 3DUI 2011, IEEE Symposium on 3D User Interfaces

Author: Laviola, Joseph, Hachet, Martin, Billinghurst, Mark, Dept. of Electrical Engineering and Computer Science, University of Central Florida [Orlando] (UCF), Visualization and manipulation of complex data on wireless mobile devices (IPARLA ), Centre National de la Recherche Scientifique (CNRS)-École Nationale Supérieure d'Électronique, Informatique et Radiocommunications de Bordeaux (ENSEIRB)-Inria Bordeaux - Sud-Ouest, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-Université Sciences et Technologies - Bordeaux 1, HITLab NZ, University of Canterbury [Christchurch], J. LaViola, M.Hachet, M. Billinghurst, Université Sciences et Technologies - Bordeaux 1 (UB)-Inria Bordeaux - Sud-Ouest, and Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-École Nationale Supérieure d'Électronique, Informatique et Radiocommunications de Bordeaux (ENSEIRB)-Centre National de la Recherche Scientifique (CNRS)
Subjects: [INFO.INFO-HC]Computer Science [cs]/Human-Computer Interaction [cs.HC], ComputingMilieux_MISCELLANEOUS, [INFO.INFO-GR]Computer Science [cs]/Graphics [cs.GR]
Abstract: International audience
Published: 2011

45. Proceedings of 3DUI 2010 - IEEE Symposium on 3D User Interfaces

Author: Hachet, Martin, Kiyokawa, Kiyoshi, Laviola, Joseph, Visualization and manipulation of complex data on wireless mobile devices (IPARLA ), Université Sciences et Technologies - Bordeaux 1-Inria Bordeaux - Sud-Ouest, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-École Nationale Supérieure d'Électronique, Informatique et Radiocommunications de Bordeaux (ENSEIRB)-Centre National de la Recherche Scientifique (CNRS), Osaka University [Osaka], Dept. of Electrical Engineering and Computer Science, University of Central Florida [Orlando] (UCF), M. Hachet, K. Kiyokawa, and J. LaViola, and Université Sciences et Technologies - Bordeaux 1 (UB)-Inria Bordeaux - Sud-Ouest
Subjects: [INFO.INFO-HC]Computer Science [cs]/Human-Computer Interaction [cs.HC], ComputingMilieux_MISCELLANEOUS, [INFO.INFO-GR]Computer Science [cs]/Graphics [cs.GR]
Abstract: International audience
Published: 2010

46. A Directional Occlusion Shading Model for Interactive Direct Volume Rendering

Author: Mathias Schott, Charles Hansen, Kadi Bouatouch, Vincent Pegoraro, Kévin Boulanger, Scientific Computing and Imaging Institute (SCI Institute), University of Utah, School of Electrical Engineering and Computer Science [Orlando], University of Central Florida [Orlando] (UCF), Perception, decision and action of real and virtual humans in virtual environments and impact on real environments (BUNRAKU), Institut de Recherche en Informatique et Systèmes Aléatoires (IRISA), Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Institut National de Recherche en Informatique et en Automatique (Inria)-Centre National de la Recherche Scientifique (CNRS)-Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Institut National de Recherche en Informatique et en Automatique (Inria)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Cachan (ENS Cachan)-Inria Rennes – Bretagne Atlantique, Institut National de Recherche en Informatique et en Automatique (Inria), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-Institut National de Recherche en Informatique et en Automatique (Inria)-Centre National de la Recherche Scientifique (CNRS)-Université de Rennes 1 (UR1), and Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-Institut National de Recherche en Informatique et en Automatique (Inria)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Cachan (ENS Cachan)-Inria Rennes – Bretagne Atlantique
Subjects: business.industry, Computer science, ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION, 020207 software engineering, Volume rendering, 02 engineering and technology, Computer Graphics and Computer-Aided Design, 3D rendering, ACM: I.: Computing Methodologies/I.3: COMPUTER GRAPHICS, [INFO.INFO-GR]Computer Science [cs]/Graphics [cs.GR], Rendering (computer graphics), Computer graphics (images), 0202 electrical engineering, electronic engineering, information engineering, Ambient occlusion, 020201 artificial intelligence & image processing, Rasterisation, Computer vision, Shading, Artificial intelligence, business, ComputingMilieux_MISCELLANEOUS, ComputingMethodologies_COMPUTERGRAPHICS
Abstract: Volumetric rendering is widely used to examine 3D scalar fields from CT/MRI scanners and numerical simulation datasets. One key aspect of volumetric rendering is the ability to provide perceptual cues to aid in understanding structure contained in the data. While shading models that reproduce natural lighting conditions have been shown to better convey depth information and spatial relationships, they traditionally require considerable (pre) computation. In this paper, a shading model for interactive direct volume rendering is proposed that provides perceptual cues similar to those of ambient occlusion, for both solid and transparent surface-like features. An image space occlusion factor is derived from the radiative transport equation based on a specialized phase function. The method does not rely on any precomputation and thus allows for interactive explorations of volumetric data sets via on-the-fly editing of the shading model parameters or (multi-dimensional) transfer functions while modifications to the volume via clipping planes are incorporated into the resulting occlusion-based shading.
Published: 2009

47. Second harmonic generation by electro-poling in femtosecond laser induced micro-structured silver containing glass

Author: Marc Dussauze, Vincent Rodriguez, Jiyeon Choi, Kevin Bourhis, Thierry Cardinal, Matthieu Bellec, Lionel Canioni, Aurelien Delestre, Martin Richardson, Evelyne Fargin, Center for Research and Education in Optics and Lasers (CREOL), University of Central Florida [Orlando] (UCF), Institut de Chimie de la Matière Condensée de Bordeaux (ICMCB), Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut Polytechnique de Bordeaux-Université de Bordeaux (UB), Centre de physique moléculaire optique et hertzienne (CPMOH), Université Sciences et Technologies - Bordeaux 1-Centre National de la Recherche Scientifique (CNRS), inst Theoret & Phys Chem Grèce, and NATL HELLEN RES FDN
Subjects: Laser patterning, [PHYS]Physics [physics], Materials science, business.industry, Poling, Second-harmonic generation, Nonlinear optics, 02 engineering and technology, 021001 nanoscience & nanotechnology, Laser, 01 natural sciences, law.invention, 010309 optics, law, Fiber laser, 0103 physical sciences, Femtosecond, Laser structuring, Optoelectronics, 0210 nano-technology, business, ComputingMilieux_MISCELLANEOUS
Abstract: Laser structuring and electro-poling has been carried out in silver containing glasses. The second-order NLO response after direct laser patterning has been investigated in the scope of developing further practical use of the material.
Published: 2009

48. Optimization of Plasma Flow Separation Control by Extremum Seeking

Author: Benard, N., Moreau, E., Griffin, J., Cattafesta, L., Caton, Samuel, Laboratoire d'Etudes Aérodynamiques (LEA), Université de Poitiers-ENSMA-Centre National de la Recherche Scientifique (CNRS), Center for Research and Education in Optics and Lasers (CREOL), and University of Central Florida [Orlando] (UCF)-School of Optics
Subjects: [PHYS.MECA.MEFL] Physics [physics]/Mechanics [physics]/Fluid mechanics [physics.class-ph], [SPI.MECA.MEFL] Engineering Sciences [physics]/Mechanics [physics.med-ph]/Fluids mechanics [physics.class-ph], [PHYS.MECA.MEFL]Physics [physics]/Mechanics [physics]/Fluid mechanics [physics.class-ph], ComputingMilieux_MISCELLANEOUS, [SPI.MECA.MEFL]Engineering Sciences [physics]/Mechanics [physics.med-ph]/Fluids mechanics [physics.class-ph]
Abstract: International audience
Published: 2009

49. Making radiance and irradiance caching practical

Author: Kadi Bouatouch, Jaroslav Křivánek, Sumanta Pattanaik, Jiří Žára, Czech Technical University in Prague (CTU), Perception, decision and action of real and virtual humans in virtual environments and impact on real environments (BUNRAKU), Institut de Recherche en Informatique et Systèmes Aléatoires (IRISA), Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Institut National de Recherche en Informatique et en Automatique (Inria)-Centre National de la Recherche Scientifique (CNRS)-Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Institut National de Recherche en Informatique et en Automatique (Inria)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Cachan (ENS Cachan)-Inria Rennes – Bretagne Atlantique, Institut National de Recherche en Informatique et en Automatique (Inria), School of Electrical Engineering and Computer Science [Orlando], University of Central Florida [Orlando] (UCF), EUROGRAPHICS, Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-Institut National de Recherche en Informatique et en Automatique (Inria)-Centre National de la Recherche Scientifique (CNRS)-Université de Rennes 1 (UR1), and Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-Institut National de Recherche en Informatique et en Automatique (Inria)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Cachan (ENS Cachan)-Inria Rennes – Bretagne Atlantique
Subjects: Hardware_MEMORYSTRUCTURES, Adaptive algorithm, Computer science, Global illumination, ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION, Irradiance, ACM: I.: Computing Methodologies/I.3: COMPUTER GRAPHICS, [INFO.INFO-GR]Computer Science [cs]/Graphics [cs.GR], Clamping, Computer graphics (images), Radiance, Algorithm, ComputingMilieux_MISCELLANEOUS, ComputingMethodologies_COMPUTERGRAPHICS, Interpolation
Abstract: Radiance and irradiance caching are efficient global illumination algorithms based on interpolating indirect illumination from a sparse set of cached values. In this paper we propose an adaptive algorithm for guiding spatial density of the cached values in radiance and irradiance caching. The density is adapted to the rate of change of indirect illumination in order to avoid visible interpolation artifacts and produce smooth interpolated illumination. In addition, we discuss some practical problems arising in the implementation of radiance and irradiance caching, and propose techniques for solving those problems. Namely, the neighbor clamping heuristic is proposed as a robust means for detecting small sources of indirect illumination and for dealing with problems caused by ray leaking through small gaps between adjacent polygons.
Published: 2008

50. Rendering Trees with Indirect Lighting in Real Time

Author: Sumanta Pattanaik, Kadi Bouatouch, Kévin Boulanger, Perception, decision and action of real and virtual humans in virtual environments and impact on real environments (BUNRAKU), Institut de Recherche en Informatique et Systèmes Aléatoires (IRISA), Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Institut National de Recherche en Informatique et en Automatique (Inria)-Centre National de la Recherche Scientifique (CNRS)-Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Institut National de Recherche en Informatique et en Automatique (Inria)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Cachan (ENS Cachan)-Inria Rennes – Bretagne Atlantique, Institut National de Recherche en Informatique et en Automatique (Inria), School of Electrical Engineering and Computer Science [Orlando], University of Central Florida [Orlando] (UCF), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-Institut National de Recherche en Informatique et en Automatique (Inria)-Centre National de la Recherche Scientifique (CNRS)-Université de Rennes 1 (UR1), and Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-Institut National de Recherche en Informatique et en Automatique (Inria)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Cachan (ENS Cachan)-Inria Rennes – Bretagne Atlantique
Subjects: Per-pixel lighting, Computer science, business.industry, 020207 software engineering, 02 engineering and technology, Volumetric lighting, Computer Graphics and Computer-Aided Design, ACM: I.: Computing Methodologies/I.3: COMPUTER GRAPHICS, [INFO.INFO-GR]Computer Science [cs]/Graphics [cs.GR], Rendering (computer graphics), Image-based lighting, Computer graphics (images), 0202 electrical engineering, electronic engineering, information engineering, 020201 artificial intelligence & image processing, Computer vision, Shading, Artificial intelligence, business, ComputingMilieux_MISCELLANEOUS
Abstract: High quality lighting is one of the challenges for interactive tree rendering. To this end, this paper presents a lighting model allowing real-time rendering of trees with convincing indirect lighting. Rather than defining an empirical model to mimic lighting of real trees, we work at a lower level by modeling the spatial distribution of leaves and by assigning them probabilistic properties. We focus mainly on precise low-frequency lighting that our eyes are more sensitive to and we add high-frequency details afterwards. The resulting model is efficient and simple to implement on a GPU.
Published: 2008

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