Publications: Articles
Articles: | |
|---|---|
| • |
Plasma Sources Science and Technology,
22:025020
2013
Resume: The origin of differences in the rotational temperatures of various molecules and ions (N-2(+)(B), OH(A) and N-2(C)) is studied in helium atmospheric-pressure guided streamers. The rotational temperature of N-2(+)(B) is room temperature. It is estimated from the emission band of the first negative system at 391.4 nm, and it is governed by the temperature of N-2(X) in the surrounding air. N-2(X) is ionized by direct electron impact in the outer part of the plasma. N-2(+)(B) is deactivated by collisions with N-2 and O-2. The rotational temperature of OH(A), estimated from the OH band at 306.4 nm, is slightly higher than that of N-2(+)(B). OH(A) is excited by electron impact with H2O during the first 100 ns of the applied voltage pulse. Next, OH(A) is produced by electron impact with OH(X) created by the quenching of OH(A) by N-2 and O-2. H2O diffuses deeper than N-2 into the plasma ring and the rotational temperature of OH(A) is slightly higher than that of N-2(+)(B). The rotational temperature of N-2(C), estimated from the emission of the second positive system at 315.9 nm, is governed by its collisions with helium. The gas temperature of helium at the beginning of the pulse is predicted to be several hundred kelvin higher than room temperature. Equipe: Département CP2S : Expériences et Simulations des Plasmas Réactifs - Interaction plasma-surface et Traitement des Surfaces ESPRITS |
| • |
NATURE PHYSICS,
9(1):49-54
2013
ISSN: 1745-2473
DOI: 10.1038/NPHYS2487
Equipe: Département P2M : Surfaces et Spectroscopies |
| • |
SCRIPTA MATERIALIA,
68:659-662
2013
ISSN: 1359-6462
Equipe: Centre de Compétences : X-Gamma rayons X et spectroscopie |
| • |
ISIJ INTERNATIONAL,
53(2):213-220
2013
ISSN: 0915-1559
Resume: The present study aims to understand the melting of the consumable electrode in the VAR process and gain some insight into the influence of an ensemble arc motion on the melting behaviour. In a previous study, a 2D axisymmetric model of the heat transfer in the cathode had been developed. Using the operating parameters as model inputs, it enabled prediction of the melt rate and the evolution of the melting area. Model results were successfully compared to melt rate measurements in an industrial VAR furnace. In recent years, it has been claimed that the electric arc may not be considered as steady and axisymmetric. Our experimental investigation of the luminosity recorded during an actual VAR heat confirms that a transient 3D behaviour may take place. Therefore, a 3D version of the previous model was set up to predict the heat transfer and melting of the electrode, using the unknown ensemble arc motion as an input. The arc is assimilated to a transient distribution of energy flux density. Results evidence that the influence of the arc motion on the shape of the electrode tip can be very important. In industrial practice, the cathode tip usually remains relatively flat during melting. The shapes of the computed electrode tips enable us to propose some arc parameters which remain compatible with both the periodic behaviour of the light emitted and the flatness of the electrode. Equipe: Centre de Compétences : ERMIONE informatique et calcul |
| • |
Bias dependence of tunneling magnetoresistance in magnetic tunnel junctions with asymmetric barriers
Journal of Physics Condensed Matter,
25(49)
2013
Equipe: Département P2M : Nanomagnétisme et Electronique de Spin |
| • |
JOURNAL OF APPLIED PHYSICS,
114
2013
ISSN: 0021-8979
DOI: 10.1063/1.4821884
Equipe: Centre de Compétences : X-Gamma rayons X et spectroscopie |
| • |
New Journal of Physics,
15
2013
Equipe: Département P2M : Nanomagnétisme et Electronique de Spin |
| • |
PHYSICAL REVIEW B,
88(12)
2013
ISSN: 1098-0121
Equipe: Département P2M : Surfaces et Spectroscopies |
| • |
PHYSICAL REVIEW LETTERS,
110(26)
2013
ISSN: 0031-9007
Equipe: Département P2M : Surfaces et Spectroscopies |
| • |
Carbohydrate Polymers,
93(2):401-411
2013
Resume: This work addresses the functionalization of chitosan thin films and its nanoliposomes blend films by a microwave-excited Ar/N2/H2 surface-wave plasma treatment which was found an effective tool to modify surface properties. Changes in the film properties (wettability, chemical composition, morphology) induced by the plasma treatment are studied using water contact angle measurements, X-ray photoelectron spectroscopy and scanning probe microscopy. The results suggest that hydrophilicity of the films is improved by plasma treatment in a plasma condition dependency manner. Water contact angle of chitosan films before and after plasma treatment are, respectively, 101° and 27°. Besides chemical changes on the surface, the nanoliposomes incorporation and plasma treatment also induce morphological modifications. Moreover, a correlation is found between the nanoliposomes composition and size, and the effects of plasma treatment. It is shown that the plasma treatment significantly improves the chitosan film functionalization. The effect of N2 content (88% and 100%) in the plasma gas mixture on the film etching is also pointed out. Equipe: Département CP2S : Expériences et Simulations des Plasmas Réactifs - Interaction plasma-surface et Traitement des Surfaces ESPRITS |