A spectral survey of CH3CCH in the hot molecular core G331.512-0.103

Interstellar matter and star formatio

Electronic properties of metal/MgO(001) interfaces

The Schottky barrier heights (SBH) at various metal-MgO interfaces (Mg, Al, Ni, Fe, Pd, and Ag) were studied by ultraviolet and X-ray photoelectron spectroscopy (UPS and XPS). In order to determine the Schottky barrier height, the energy distance between the O2s core level of MgO and the MgO valence band maximum (VBM) is determined to be $18.0\pm 0.1$ eV at first. The Schottky barrier heights variation with metal Pauling electronegativities is linear fitted with a slope parameter of $1.86 \pm 0.15$

Western Hellenic subduction and Cephalonia Transform: local earthquakes and plate transport and strain

International audienceFocal parameters of local earthquakes in the region of the Ionian Islands of western Greece are constrained with a temporary dense array of three-component seismographs operated jointly offshore and onshore. Seismic deformation is documented to be confined to the east of the N20°E-striking steep continental slope west of Cephalonia island, the right-lateral Cephalonia Transform Fault, CTF, inferred from large earthquakes. The pre-Apulian continental material appears to be only deforming east of the transform fault, where it is in upper plate position to the Hellenic subduction. East of the transform fault, the transmission velocity tomography from local earthquakes, compared in depth-section with a previous marine reflection profile, provides evidence in support of a shallow landward dipping boundary around 12 km deep under the Ionian Islands along which they may override the lower plate. On either side of this interface local earthquakes occur with different focal mechanisms, in support with its interpretation as the interplate. Under Cephalonia island, reverse-faulting deforms the upper plate along NW–SE structures, which may also be affected by left-lateral bookshelf-faulting. Small earthquakes show normal faulting along the western coast of Cephalonia and its extension 20 km SSW, the trace of the CTF as inferred from the occurrence of the large strike-slip earthquakes. Another group of normal-fault earthquakes locates in the lower plate from under Cephalonia to Zante, just outboard of a possible change of interplate dip suggested from reflection seismics landward under the islands. These normal-fault earthquakes appear to coincide in position with that of the load imposed by the upper plate transported over them, rather than occurring in an outer rise, outboard the plate boundary and trench, as observed in other subductions and attributed to the control by the flexural bending of the lower plate under the pull of the sinking slab. Interpretation has to consider several peculiar features of plate interaction in western Greece with respect to a steady-state model for major subduction zones, in particular: a fast deformation of the upper plate in front of an orogenically overthickened crust and of the southwestward push of extruding Anatolia; its transport, which is the cause of the migration of the plate boundary rather than the roll-back of a slab which has been proposed to be detached; possibly a flat and ramp shape of the interplate; the geometrical complexity of the shear limit across the CTF between subduction and collision, and the nearby variation of the nature of the foreland crust

Upper mantle structure of shear-waves velocities and stratification of anisotropy in the Afar Hotspot region

International audienc

Rapport quadriennal 1995-1998

Seismic approaches reveal the lithospheric structure and geodynamic contexts of Piton de la Fournaise and Etna. A set of tomographic experiments constrains their internal structures with a resolution providing insight into edifice evolution and eruptive behavior. The hotspot context of La Réunion island thus appears to differ from the Hawaiian one by a reduced plate flexure, large proportion of low velocity-density in the edifice, crustal underplating under the presently active part, which may be seen as the level of transposition from primary melts into the more tholeitic products erupted. Structural heterogeneities of the preexisting plate are documented which may control magmatism in addition to slow plate/hotspot motion. Two completely different tomographies establish a high-velocity central core under the active volcano summit area which contrasts with the surroundings interpreted as eruptives or transported material and rises from the top of the oceanic plate. Another distinct high-velocity body to the East, which top has been drilled, is imaged to be rooted in the plate. So-called rift-zones of the active volcano are not marked by velocity anomalies, hence do not appear to be magmatic. High resolution location of earthquakes, heterogeneity in Vp/Vs and magnitude-number evolution can be correlated for the preeruptive magma migration to the most recent eruption. Mt Etna is not in a simple geodynamic context typical for volcanism. Marine reflection seismics reveal extension of crustal scale, which has succeeded to the compression related to the subduction at the Calabro-Sicilian arc. It is interpreted as marking a change in slab coupling, with which the development of Etna appears coeval... (D'après résumé d'auteur

A simulation of the temperature distribution in the SPIRAL target

We developed a model and a computer program to calculate the temperature distribution in the target which will be used in the SPIRAL project a GANIL. The results of the numerical simulation are compared with measurements performed with several types of targets

Study of reactions induced by

We present the results of experiments using a 6He beam on a 9Be target at energies 7 − 9 times the Coulomb barrier. Angular distributions of the elastic, inelastic scattering (target breakup) and the a-particle production in the 6He+9Be collision have been analysed. Total reaction cross sections were obtained from the elastic scatteringanalyses and a considerable enhancement has been observed by comparing to stable systems

Recent results on reactions with radioactive beams at RIBRAS (Radioactive Ion Beams in Brazil)

We present a quick description of RIBRAS (Radioactive Ion beams in Brazil), which is a superconducting double solenoid system, installed at the Pelletron Laboratory of the University of São Paulo and extends the capabilities of the original Pelletron Tandem Accelerator of 8MV terminal voltage (8UD) by producing secondary beams of unstable nuclei. The experimental program of the RIBRAS covers the study of elastic and inelastic scattering with the objective to study the interaction potential and the reaction mechanisms between weakly bound (RIB) and halo (6He and 8B) projectiles on light, medium and heavy mass targets. With highly purified beams, the study of resonant elastic scattering and resonant transfer reactions, using inverse kinematics and thick targets, have also been included in our recent experimental program.SCOPUS: cp.jinfo:eu-repo/semantics/publishe

Four-body effects in the He6+Ni58 scattering

AbstractWe present angular distributions of the He6+Ni58 scattering measured at three bombarding energies above the Coulomb barrier: Elab=12.2 MeV,16.5 MeV,and 21.7 MeV. The angular distributions have been analysed in terms of three- and four-body Continuum-Discretized Coupled-Channels calculations considering the effect of the 6He breakup. A behaviour in the cross section at large angles has been observed which was reproduced only by the four-body Continuum-Discretized Coupled-Channels calculation