bernard revaz - Academia.edu (original) (raw)

Papers by bernard revaz

Basic Processes in Fully and Partially Ionized Plasmas Efficient Absorption and Intense Soft X-Ray Emission From Gas Cluster Plasmas Irradiated by 25-ps Laser Pulses..................................................... S. Sailaja, RA Khan, PA Naik, and PD Gupta 1006 Microwave Generation and Micro...

REGULAR ISSUE PAPERS Basic Processes in Fully and Partially Ionized Plasmas Efficient Absorption ... more REGULAR ISSUE PAPERS Basic Processes in Fully and Partially Ionized Plasmas Efficient Absorption and Intense Soft X-Ray Emission From Gas Cluster Plasmas Irradiated by 25-ps Laser Pulses . . . . ................................................. S. Sailaja, RA Khan, PA Naik, and PD Gupta 1006 Microwave Generation and Microwave-Plasma Interaction Self-Consistent Nonlinear Investigation of an Outer-Slotted-Coaxial Waveguide Gyroton Traveling-Wave Amplifier. . . . .................................... ...C.-R. Qiu, Z.-B. Ouyang, S.-C. Zhang, H.-B. Zhang, and J.-B. ...

Installing a EC Sensor on a remote location

1.Introduction The objective of this document is to provide a descri... more 1.Introduction The objective of this document is to provide a description of the dataset entitled "Installing an EC Sensor on a remote location". The guidelines on how to use the files are included in this document. The dataset is part of the deliverables D9.4 (First data management plan) and D9.5 (Final data management plan). 2.Description of the data 2.1.Origin This dataset includes data collected from the experiments related to the task "Installing a EC Sensor on a remote location" as part of the WP8 "validation in the industrial scenario". 2.2.Type The data consists of Eddy Current (EC) measurements. 2.3.Formats The acquired data are available in several formats. 2.3.1.*.sidata files These files are proprietary format that can be opened with the software "UPecView" supplied by Sensima Inspection (http://www.sensimainsp.com). This software provides an interface familiar to what expected by eddy-current inspectors. Each file includes all the relevant information that may be used for analysis: the measurements and the instrument configuration (ex. Excitation frequency of the probe) is contained in this file. 2.3.2.*.csv files The csv files contain an export of the measurements only (without instrument settings); a comma separator is used. Each row is composed of the following variables: Time (s), Signal (in-phase), Signal (out-of-phase), Channel/state, Extra signal (ADC), Encoder coordinate 1 (x), Encoder coordinate 2 (y), Encoder coordinate 3 (z), Encoder error status. 3.Measurements indexing Folder Filename Creation date Description Target Location EXP001 0001A 12.03.2019 Calibration block scan Calibration block Seville, Spain EXP001 0001B 12.03.2019 Manual reference scan on weld pipe Calibration block Seville, Spain EXP001 0002A 12.03.2019 Drone overall scan inspection and sensor deployment Cement kiln Seville, Spain EXP001 0002B 12.03.2019 Dep [...]

$Research paper thumbnail of Surface physics, nanoscale physics, low-dimensional systems-Thermomechanical behavior of surface acoustic waves in ordered arrays of nanodisks studied by near-infrared pump-probe diffraction$

Surface physics, nanoscale physics, low-dimensional systems-Thermomechanical behavior of surface acoustic waves in ordered arrays of nanodisks studied by near-infrared pump-probe diffraction

A light-scattering study of dynamical carrier properties in cuprate systems

Ferroelectrics, 2001

ABSTRACT Results of inelastic light-scattering experiments are analysed in terms of a memory func... more ABSTRACT Results of inelastic light-scattering experiments are analysed in terms of a memory function M(ω) = ωλ(ω)+iΓ(ω). Using this approach dynamical scattering rates Γ(ω) = 1/τ(ω) and mass-enhancement factors 1 + λ(ω) = m*(ω)/m for the carriers are derived as a function of temperature T and doping p. The obtained quantities are in qualitative agreement with results from infrared spectroscopy and longitudinal transport. In addition, Raman scattering reveals new information about the anisotropy of the carrier properties. The anisotropy increases substantially towards lower doping when the influence of electronic correlations gain importance. The analysis turns out to be very useful for the understanding of the pseudogap in the normal state.

Numerical Simulation of the Heat Transfer and Elastic Dynamics of Nanodisks Arrays in Pump-Probe Laser Experiment

Thin film microcalorimeter for heat capacity measurements in high magnetic fields

Review of Scientific Instruments, 2002

Si–N based membrane calorimeters are a promising technology for the study of thermal properties o... more Si–N based membrane calorimeters are a promising technology for the study of thermal properties of small quantities of materials in both pulsed and steady-state magnetic fields to 60 T and beyond. We present results that demonstrate our ability to measure the heat capacity of thin film samples from 2–300 K in steady-state fields up to 8 T. These measurements include the magnetoresistance of the Pt and Nb–Si thermometers and focus on confirming that the thermal conductance of the Si–N membrane does not change significantly in magnetic fields. This means the thermal conductance needs to be measured only in zero field, reducing the measurement time in high field. This is particularly important for future measurements in fields up to 60 T.

Physical Review B, 2000

We present a detailed study on the behaviour of vortex cores in Bi2Sr2CaCu2O 8+δ using scanning t... more We present a detailed study on the behaviour of vortex cores in Bi2Sr2CaCu2O 8+δ using scanning tunneling spectroscopy. The very irregular distribution and shape of the vortex cores imply a strong pinning of the vortices by defects and inhomogeneities. The observed vortex cores seem to consist of two or more randomly distributed smaller elements. Even more striking is the observation of vortex motion where the vortex cores are divided between two positions before totally moving from one position to the other. Both effects can be explained by quantum tunneling of vortices between different pinning centers.

Thermochimica Acta, 2005

We have used silicon micromachining techniques to fabricate devices for measuring specific heat o... more We have used silicon micromachining techniques to fabricate devices for measuring specific heat or other calorimetric signals from microgram-quantity samples over a temperature range from 1.7 to at least 525 K in magnetic fields to date up to 8 T. The devices are based on a robust silicon-nitride membrane with thin film heaters and thermometers. Different types of thermometers are used for different purposes and in different temperature ranges. These devices are particularly useful for thin film samples (typically 100-400 nm thick at present) deposited directly onto the membrane through a Si micromachined evaporation mask. They have also been used for small bulk samples attached by conducting grease, Ga or In, and for powder samples dissolved in a solvent and dropped onto devices. The measurement technique used (relaxation method) is particularly suited to high field measurements because the thermal conductance can be measured once in zero field and is field independent, while the time constant of the relaxation does not depend on thermometer calibration.

Physical Review Letters, 1998

Vortex cores in under-and overdoped Bi 2 Sr 2 CaCu 2 O 81d are studied by local probe tunneling s... more Vortex cores in under-and overdoped Bi 2 Sr 2 CaCu 2 O 81d are studied by local probe tunneling spectroscopy. At the center of the cores, we find a gaplike structure at the Fermi level which scales with the superconducting gap, but no quasiparticle bound states. This low temperature pseudogap is intimately related to the superconducting gap and shows striking similarities with the normal state pseudogap measured above T c. A possible interpretation is that both pseudogap structures reflect the same "normal" state containing phase incoherent excited pair states. [S0031-9007(98)05816-5]

Physical Review Letters, 2002

The electron dynamics in the normal state of Bi2Sr2CaCu2O 8+δ is studied by inelastic light scatt... more The electron dynamics in the normal state of Bi2Sr2CaCu2O 8+δ is studied by inelastic light scattering over a wide range of doping. A strong anisotropy of the electron relaxation is found which cannot be explained by single-particle properties alone. The results strongly indicate the presence of an unconventional quantum-critical metal-insulator transition where "hot" (antinodal) quasiparticles become insulating while "cold" (nodal) quasiparticles remain metallic. A phenomenology is developed which allows a quantitative understanding of the Raman results and provides a scenario which links single-and many-particle properties.

Journal of Physics and Chemistry of Solids, 2000

We have measured the electron momentum density in both insulating PrBa 2 Cu 3 O 7Ϫd and supercond... more We have measured the electron momentum density in both insulating PrBa 2 Cu 3 O 7Ϫd and superconducting YBa 2 Cu 3 O 7Ϫd : We find a remarkable difference in the anisotropy of the momentum density, even though LDA based calculations predict similar behaviour for both. Our results can be explained assuming Pr on Ba-site substitution disorder and we propose that this phenomenon is responsible for the observed effects.

Journal of Low Temperature Physics, 1996

We present local probe tunneling spectroscopy of Bi2Sr2CaCu2Os+ 6 single crystals for different o... more We present local probe tunneling spectroscopy of Bi2Sr2CaCu2Os+ 6 single crystals for different oxygen concentrations, from optimally doped (Tc=92.2 K) to highly overdoped (Tc=56.0 K) phases. With increasing oxygen overdoping, the superconducting gap (Ap) is reduced and the dip structure beyond Ap at negative sample bias ! shifts toward the Fermi energy. Apart from the shift in energy of these features, the generic shape of the tunneling spectra remains unchanged. The gap roughly scales with T c, and 2Ap/kBT c stays large even in the highly overdoped phase. We also present preliminary results on the temperature dependence of the tunneling spectra. They are consistent with a gap that is largely independent on temperature up to the vicinity oft c.

Journal of Electron Spectroscopy and Related Phenomena, 2000

During past years, scanning tunneling spectroscopy (STS) investigations of high temperature super... more During past years, scanning tunneling spectroscopy (STS) investigations of high temperature superconductors have revealed unusual characteristics of the superconducting gap. We present here the temperature dependence of the tunneling conductance spectra on YBa Cu O and Bi Sr CaCu O single crystals. We discuss similarities and differences 2 3 7 2d 2 2 2 81d between these two compounds. In particular we note that while in Bi Sr CaCu O a pseudogap is observed above the 2 2 2 81d critical temperature, even in overdoped samples, we find no indication of a pseudogap in optimally doped YBa Cu O 2 3 7 2d above T. This is consistent with other striking differences between the two systems and supports the interpretation of the c pseudogap in terms of strong superconducting correlations.

Surface physics, nanoscale physics, low-dimensional systems-Thermomechanical behavior of surface acoustic waves in ordered arrays of nanodisks studied by near-infrared pump-probe diffraction

A Compton scattering study of insulating PrBa 2 Cu 3 O 7− δ and superconducting YBa 2 Cu 3 O 7− δ

Physical Review Letters, 2002

We report the doping dependence of the order of the ferromagnetic metal to paramagnetic insulator... more We report the doping dependence of the order of the ferromagnetic metal to paramagnetic insulator phase transition in La 1-x Ca x MnO 3. At x = 0.33, magnetization and specific heat data show a first order transition, with an entropy change (2.3 J/molK) accounted for by both volume expansion and the discontinuity of M ~ 1.7 m B via the Clausius-Clapeyron equation. At x = 0.4, the data show a continuous transition with tricritical point exponents a = 0.48±0.06, b = 0.25±0.03, g = 1.03±0.05, and d = 5.0±0.8. This tricritical point separates first order (x<0.4) from second order (x>0.4) transitions.

Proposal for an all-optical nano-calorimetric technique

Specific heat anomalies on the vortex melting line in YBa2Cu3O7−δ up to B=23 teslas: Observation of first- and second-order transitions, effect of oxygen doping, field orientation, crystal purity and detwinning

Physica C: Superconductivity, 1997

Abstract Because strong fluctuations transform the upper critical field line B c2 (T) into a smoo... more Abstract Because strong fluctuations transform the upper critical field line B c2 (T) into a smooth crossover, vortex melting is now believed to be the only true phase transition of high temperature superconductors in a magnetic field. We review recent work performed by the Geneva and Grenoble laboratories in the calorimetric determination of the melting line B m (T) in YBa 2 Cu 3 O x . This includes three crystals showing specific heat steps upon crossing B m (T), and three crystals showing specific heat peaks. Adiabatic calorimetry (up to 23 T) and oscillating dynamic methods (up to 7 T) are used. We investigate the effect of field orientation (B//c and B⊥c), oxygen concentration x (6.95 – 6.97), and detwinning. These experiments document both processes that may occur on the B m (T) line, depending on pinning properties: the melting of a vortex lattice with a first-order transition, and the melting of a vortex glass with a second-order or continuous transition.

Metals

Powder bed fusion (PBF) is the most commonly used additive manufacturing process for fabricating ... more Powder bed fusion (PBF) is the most commonly used additive manufacturing process for fabricating complex metal parts via the layer-wise melting of powder. Despite the tremendous recent technological development of PBF, manufactured parts still lack consistent quality in terms of part properties such as dimensional accuracy, surface roughness, or relative density. In addition to process-inherent variability, this is mainly owing to a knowledge gap in the understanding of process influences and the inability to adequately control them during part production. Eddy current testing (ECT) is a well-established nondestructive testing technique primarily used to detect near-surface defects and measure material properties such as electrical conductivity in metal parts. Hence, it is an appropriate technology for the layer-wise measuring of the material properties of the fused material in PBF. This study evaluates ECT’s potential as a novel in situ monitoring technology for relative part densi...

IEEE Robotics and Automation Letters

We present the design, motion planning and control of an aerial manipulator for non-trivial physi... more We present the design, motion planning and control of an aerial manipulator for non-trivial physical interaction tasks, such as pushing while sliding on curved surfaces-a task which is motivated by the increasing interest in autonomous non-destructive tests for industrial plants. The proposed aerial manipulator consists of a multidirectional-thrust aerial vehicle-to enhance physical interaction capabilities-endowed with a 2-DoFs lightweight arm-to enlarge its workspace. This combination makes it a truly-redundant manipulator going beyond standard aerial manipulators based on collinear multirotor platforms. The controller is based on a PID method with a 'displaced' positional part that ensures asymptotic stability despite the arm elasticity. A kinodynamic task-constrained and control-aware global motion planner is used. Experiments show that the proposed aerial manipulator system, equipped with an Eddy Current probe, is able to scan a metallic pipe sliding the sensor over its surface and preserving the contact. From the measures, a weld on the pipe is successfully detected and mapped.

Installing a EC Sensor on a remote location

Surface physics, nanoscale physics, low-dimensional systems-Thermomechanical behavior of surface acoustic waves in ordered arrays of nanodisks studied by near-infrared pump-probe diffraction

A light-scattering study of dynamical carrier properties in cuprate systems

Ferroelectrics, 2001

Numerical Simulation of the Heat Transfer and Elastic Dynamics of Nanodisks Arrays in Pump-Probe Laser Experiment

Thin film microcalorimeter for heat capacity measurements in high magnetic fields

Review of Scientific Instruments, 2002

Physical Review B, 2000

Thermochimica Acta, 2005

Physical Review Letters, 1998

Physical Review Letters, 2002

Journal of Physics and Chemistry of Solids, 2000

Journal of Low Temperature Physics, 1996

Journal of Electron Spectroscopy and Related Phenomena, 2000

Surface physics, nanoscale physics, low-dimensional systems-Thermomechanical behavior of surface acoustic waves in ordered arrays of nanodisks studied by near-infrared pump-probe diffraction

A Compton scattering study of insulating PrBa 2 Cu 3 O 7− δ and superconducting YBa 2 Cu 3 O 7− δ

Physical Review Letters, 2002

Proposal for an all-optical nano-calorimetric technique

Physica C: Superconductivity, 1997

Metals

IEEE Robotics and Automation Letters