Search

Your search keyword '"Harnois, C."' showing total 180 results
Start Over Author "Harnois, C."
180 results on '"Harnois, C."'

1. The decrease of the critical current of coated conductors when a perpendicular magnetic field is applied : a Josephson effect point of view

Author

McLoughlin, C., Thimont, Y., Noudem, J., Harnois, C., and Bernstein, P.

Subjects
Condensed Matter - Superconductivity
Abstract

A large decrease is observed in the critical current density of YBCO coated conductors (CC) and related compounds when a strong perpendicular magnetic field is applied. While measurements are generally carried out at 77K only, here we present a magnetic technique permitting to determine the critical current per unit width of conductor (Icr/w) in a large temperature range. We report measurements carried out on various CCs that show that, in addition to the reduction in the critical temperature that can be attributed to the low value of the irreversibility field near Tc, the field application results in a large decrease of Icr/w at all temperatures. We ascribe this reduction to the Josephson behaviour of the twin boundaries included in the YBCO layer.

Published
2012

2. The influence of twin boundaries on the Flux Line Lattice structure in YBaCuO: a study by Small Angle Neutron Scattering

Author

Simon, Ch., Pautrat, A., Poulain, G., Goupil, C., Leblond-Harnois, C., Chaud, X., and Brulet, A.

Subjects
Condensed Matter - Superconductivity, Condensed Matter - Materials Science
Abstract

The influence of Twin Boundaries (TB) on the Flux Line Lattice(FLL) structure was investigated by Small Angle Neutron Scattering (SANS). YBaCuO single crystals possessing different TB densities were studied. The SANS experiments show that the TB strongly modify the structure of the FLL. The flux lines meander as soon as the magnetic field makes an angle with the TB direction. According to the value of this angle but also to the ratio of the flux lines density over the TB density, one observes that the FLL exhibits two different unit cells in the plane perpendicular to the magnetic field. One is the classical hexagonal and anisotropic cell while the other is affected by an additional deformation induced by the TB. We discuss a possible relation between this deformation and the increase of the critical current usually observed in heavily twinned samples., Comment: accepted for publication in Phys Rev B

Published
2004
Full Text
View/download PDF

7. Study of CeO(sub 2) + SnO(sub 2) + Ag doped YBCO as a candidate for welding composition

Author

Harnois, C.

Subjects
Superconductivity -- Measurement, Semiconductor doping -- Chemical properties, Semiconductor doping -- Thermal properties, Business, Electronics, Electronics and electrical industries
Abstract

A study of the doping mixture, CeO(sub 2) + SnO(sub 2) + Ag that determine its different physico-chemical properties and its use as a welding material is presented. The addition of silver decreases the decomposition temperature of Ceo(sub 2) + SnO(sub 2) doped Y123 from at least 30 degree Celsius and the critical densities under all magnetic fields are totally similar to the Ceo(sub 2) + SnO(sub 2) doped Y123 ones.

Published
2004

14. The role of a-axis grains in the transition to the normal state of YBa2Cu3O7-δfilms and of 2G-coated conductors when induced by high electrical current densities.

Author

Bernstein, P., Ferro, G., Harnois, C., Loughlin, C. Mc, Noudem, J., Osorio, M. R., Thimont, Y., Veira, J. A., Vidal, D., and Vidal, F.

Subjects
THIN film research, ELECTRICAL conductors, ELECTRIC currents, ELECTRIC potential measurement, VORTEX motion
Abstract

The influence of surface defects, in particular of a-axis grains, on the transition to the normal state induced by high current densities in YBa2Cu3O7-δ (YBCO) thin films and in a commercial 2G-coated conductor is investigated. For that purpose, the surface of the samples is observed by scanning electron microscopy and isothermal current-voltage curves are measured at different temperatures with pulsed currents up to the quenching value I*. The results show that the ratio of I* to the critical current is large if a-axis grains are not visible at the surface of the YBCO films, while it is much lower if the surface includes a-axis grains as this is the case for the coated conductor. The connection between the transition onset and the vortex dynamics, as well as the role of the a-axis grains in this process are discussed. The relation between the I* values obtained from thermal calculations and those resulting from vortex dynamics considerations is also discussed, as well as the possible consequences suggested by this work for the different applications of the coated conductors. [ABSTRACT FROM AUTHOR]

Published
2014
Full Text
View/download PDF

24. Influence of twin boundaries on the flux-line-lattice structure in Y Ba 2 Cu 3 O 7 − δ : A small-angle neutron scattering

Author

Simon, Ch., Pautrat, A., Poullain, G., Goupil, C., Leblond-Harnois, C., Chaud, Xavier, Brulet, A., Laboratoire de cristallographie et sciences des matériaux (CRISMAT), École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS)-Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Institut de Chimie du CNRS (INC), Laboratoire d'Ergonomie et de Sciences Cognitives pour les Transports (INRETS/LESCOT), Institut National de Recherche sur les Transports et leur Sécurité (INRETS), Centre National de la Recherche Scientifique (CNRS), Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Laboratoire national des champs magnétiques intenses - Grenoble (LNCMI-G), Université Joseph Fourier - Grenoble 1 (UJF)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS), Laboratoire Léon Brillouin (LLB - UMR 12), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Saclay, Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche sur les Matériaux Avancés (IRMA), Normandie Université (NU)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Rouen Normandie (UNIROUEN), Normandie Université (NU)-Institut national des sciences appliquées Rouen Normandie (INSA Rouen Normandie), Institut National des Sciences Appliquées (INSA)-Normandie Université (NU)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Rouen Normandie (UNIROUEN), Institut National des Sciences Appliquées (INSA)-Normandie Université (NU)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), and Normandie Université (NU)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)

Subjects
[PHYS.HIST]Physics [physics]/Physics archives, ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2004

27. Early acquisition of bowel segment-specific Bcl-2 homolog expression profiles during development of the human ileum and colon

Author

Vachon, P.H., Cardin, E., Harnois, C., Reed, J.C., Plourde, A., and Vézina, A.

Subjects
Enterocyte, Gut, 6 - Ciencias aplicadas::61 - Medicina::616 - Patología. Medicina clínica. Oncología::616.3 - Patología del aparato digestivo. Odontología [CDU]
Abstract

The adult small and large intestines display distinct expression profiles of Bcl-2 homologs, known regulators of apoptosis. This is thought to indicate that control mechanisms of intestinal apoptosis are gut segment-specific. Little is known on the expression of Bcl-2 homologs during gut development. In man, intestinal features and functions are acquired largely by mid-gestation (18-20 wks); the question whether segment-specific controls of intestinal apoptosis are also acquired early during development remains open. In the present study, we approached this by investigating the expression of six Bcl-2 homologs (Bcl-2, Bcl-XL, Mcl- 1, Bax, Bak, Bad), and one nonhomologous associated molecule (Bag-1), during development of the human ileum and colon (12-20 wks of gestation). Beginning at 18 wks, we found that the epithelial localization of Bcl-2 homologs displayed differential patterns (or gradients) in both the ileum and colon; however, the patterns of some of the homologs differed between the two segrnents. For instance, Bag-1 and Bcl-2 exhibited crypt-villus decreasing gradients of expression in the ileum but not in the colon, whereas Mcl-1 displayed differing compartimentalizations between the two segments. Further analyses indicated that the steady-state expression levels of Bcl-2 homologs underwent modulations between 12 and 20 wks; however, the obsewed developmental profiles contrasted significantly between the two segments. For example, Bcl-2, Bag-1 and Bak levels increased in the colon, but the levels of these same homo.logs decreased in the ileum. Furthermore, by 18-20 wks, we found that the expression levels of each Bcl-2 homolog analyzed differed greatly between the ileum and colon. Altogether, these data indicate that the expression of Bcl-2 homologs is modulated differentially during human gut development in order to establish, by midgestation, distinct expression profiles for the small and large intestines. This in turn suggests that gut segmentspecific control mechanisms of human intestinal apoptosis are acquired early during fetal life.

Published
2001

Catalog

Books, media, physical & digital resources
See catalog results