Showing papers in "Comptes Rendus Physique in 2010"

TL;DR: In this paper, the authors present some aspects of the technology of terahertz heterodyne receiver front-ends dedicated to astrophysics, planetary and atmospheric sciences, focusing on frequency multipliers and on Schottky mixers.

TL;DR: In this article, real-time terahertz (THz) imaging technologies which make use of uncooled bolometer-type infrared focal plane arrays (FPAs) and quantum cascade lasers (QCLs) are reviewed.

TL;DR: In the field of materials science, it is common to relate mechanical or physical behaviour to microstructure in order to optimize materials Usually the observation of the micro-structure is made using an optical or electronic microscope to obtain images in two dimensions However, the measurable parameters in 2D are limited and often the techniques involved to obtain these images are destructive as discussed by the authors.

TL;DR: In this paper, a high-resolution terahertz tomography has been demonstrated by ultra short tera-hertz pulses using optical fiber and a nonlinear organic crystal.

TL;DR: Terahertz spectroscopy and THz imaging techniques are expected to have great potential for carrying out the non-invasive analysis of artworks as discussed by the authors, and they can perform three-dimensional material mapping non-destructively by spectroscopic imaging.

TL;DR: In this paper, an elasto-viscoplastic phase field model was proposed to capture the physical mechanisms at the origin of these complex morphologies in two different situations: polytwinned microstructures observed in martensitic alloys, and the understanding of the rafting phenomena observed in superalloys under creep.

TL;DR: Fast field-cycling magnetic resonance imaging (FFC-MRI) has a number of significant applications and advantages over conventional techniques, such as protein measurement via quadrupolar cross-relaxation, contrast agent studies, localised relaxometry and FFCMRI with magnetisation transfer contrast as mentioned in this paper.

TL;DR: In this paper, the authors present numerical simulations of indentation at different scales, including atomic and molecular dynamics simulations, and finite element simulations within the framework of crystal plasticity, using a dislocation dynamics model that can simulate dislocation organization.

TL;DR: In this article, the nucleation, growth and coalescence of voids are reviewed with a focus on the underlying physics, considering the introduction of different length scales associated with the microstructure and damage process.

TL;DR: Inverse Laplace Transformations (ILT) as mentioned in this paper can be used to examine the behavior of liquid state molecules in a porous matrix, particularly when the signal is characterized by multi-exponential decay, for example in spin relaxation or in the dephasing of the NMR spin echo signal associated with molecular diffusion under the influence of pulsed magnetic or internal field gradients.

TL;DR: In this article, the main physical ideas for application of field effect transistors for generation and detection of Terahertz radiation are discussed, where the authors show that the dynamics of a short channel FET at THz frequencies is dominated by plasma waves.

TL;DR: In this article, an X-band Doppler radar has been deployed to assess short range (inferior to 2000 m) wake vortex monitoring capabilities in all weather conditions (dry and wet conditions).

TL;DR: In this paper, a new view of the evolution of the outer Solar System that emerges from the so-called "Nice model" and its recent extensions is presented, with a very "dynamical" Solar System, with giant planets affected by both radial migrations and a temporary orbital instability.

TL;DR: A review of the state of the art in personal exposure measurements at radio frequency signals can be found in this paper, where the authors consider the physical dosimetry concerning interactions between radio waves and the body and analyze the gathered data in relation to possible determinants of exposure.

TL;DR: In this article, a reverberation chamber with an aperture on the front face was used to generate high power microwave pulses from a low power arbitrary wave generator, where high amplitude peaks were generated outside the chamber thanks to the long spreading time of the signals inside.

TL;DR: In this paper, the authors combine the description of microsegregation with a direct modeling approach of grain structure and macrosegregation (deviation of the alloy composition within the cast part).

TL;DR: In this paper, a rappel de l'historique du sujet, cet article se concentre sur les developpements tres rapides et recents du domaine.

TL;DR: Investigation of the association between radiofrequency exposure (RF-EMF) and non-specific health complaints in electromagnetic hypersensitive (EHS) individuals found no evidence that health disturbances of EHS individuals were associated with RF- EMF exposure.

TL;DR: In this paper, it is shown that cleavage fracture is controlled by physical events occurring at different scales: initiation at sub-micrometric particles, propagation across grain boundaries (10-50 microns) and final fracture at centimetric scale.

TL;DR: In this paper, the authors show that dislocation dynamics simulations provide a unique opportunity for establishing scale transitions in crystal plasticity and provide guidelines for the modeling of collective dislocation behavior.

TL;DR: In this paper, high pressure deformation experiments carried out on olivine single crystals under synchrotron radiation, together with estimations of lattice friction based on first-principle calculations, show a transition from easy [100] to easy [001] slips as pressure and temperature (thus depth) increases.

TL;DR: A modelisation of the radio wave propagation in straight arch-shaped tunnels is realized by using asymptotic methods, such as Ray Tracing and Ray Launching, combined with the tessellation of the arched section.

TL;DR: In this paper, the magnetic field dependence of the nuclear spin-lattice relaxation rate 1 / T 1 ( ω 0 ) is analyzed for high surface area porous materials including calibrated porous silica glasses, granular packings, heterogeneous catalytic materials, and natural porous materials such as clay minerals and rocks.

TL;DR: In this article, the average local translational mobility at the interface is reduced by approximately factor of three from the bulk and there is anisotropy induced in the motions caused by the excluded volume created by the presence of the protein.

TL;DR: Comparison among sham and exposed groups revealed no significant differences, suggesting that in utero and post-natal exposure to Wi-Fi did not damage the brains of the young rats.

TL;DR: In this article, a reversion treatment (instantaneous heating of the microstructure to a temperature high enough to induce some dissolution of the precipitates) can be used to calibrate all physical parameters of the model independently.

TL;DR: In this article, an overview of experimental results on THz detection by FETs discussing possibilities of improvement of their performance and application for THz room temperature imaging is presented. But the authors do not discuss the application of their work in the field effect transistors (FETs).

TL;DR: In this article, a high-electron mobility transistor was used to demonstrate terahertz radiation from two-dimensional (2D) electron systems in semiconductor nano-heterostructures.

TL;DR: In this article, the basic principles of fabrication, of electromechanical actuation and detection of the nanotube motion are reviewed and the first experimental results obtained which have allowed us to understand the effect of the electromachanical on the mechanical properties; and to test the carbon nanotubes capabilities for mass sensing.

TL;DR: Four families of image processing techniques are shown to be particularly useful to the disaster manager: zoning, counting of objects, roads and network detection, and damage assessment resulting from a series of different radiometric and geometric methods.