Amélioration de l'estimation de la SER de cibles étendues par une approche champ proche

National audienceCet article présente une nouvelle méthode d'estimation de la Surface Equivalente Radar (SER) d'objets de grandes dimensions en milieu réaliste et prenant en compte la problématique champ proche par l'utilisation de la fonction de Green dyadique. Les simulations ont été réalisées sur des cibles métalliques de grandes dimensions placées de 0 à 10 km du radar, pour des fréquences comprises entre 1 et 20 GHz

Use of dyadic Green's function for RCS estimation of large targets

International audienceThis paper presents a new method to estimate the Radar Cross Section (RCS) of a large object in its environment. This estimation method is based on the use of dyadic Green's function method which includes near-field issues. Simulations have been made on perfect electrically conducting (PEC) targets in a frequency band between 1 to 20 GHz. Some simulated results of RCS estimation of a PEC target taking into account the sea effect, are also presented here

Improvement of RCS estimation of large targets by using near-field approach

International audienceThis paper presents a new method in order to estimate the Radar Cross Section (RCS) of large objects in their environments. Object is defined as a volumetric surface and will be considered as a metallic target at a finite distance. This estimation is based on the use of dyadic Green's function method which includes near-field issues. Simulations have been made in a frequency band between 1 to 20 GHz. Some simulated results of RCS estimation of a large metallic target taking into account the sea effect, are presented

Amélioration de l'estimation de la SER de cibles étendues par une approche champ proche

National audienceCet article présente une nouvelle méthode d'estimation de la Surface Equivalente Radar (SER) d'objets de grandes dimensions en milieu réaliste et prenant en compte la problématique champ proche par l'utilisation de la fonction de Green dyadique. Les simulations ont été réalisées sur des cibles métalliques de grandes dimensions placées de 0 à 10 km du radar, pour des fréquences comprises entre 1 et 20 GHz

Sociologie, histoire, anthropologie des dynamiques culturelles

Jacques Cheyronnaud, Élisabeth Claverie, chargés de recherche au CNRS Anthropologie des dispositifs cultuels Une première partie a été consacrée par J. Cheyronnaud à introduire à une anthropologie du christianisme en Europe et notamment, à traiter des risques d’une circularité conceptuelle s’agissant par exemple des termes de culte, rite et rituel, cérémonie : leur passage en réélaborations théologiques issues de lectures de travaux anthropologiques par exemple sur les questions de rituel ou ..

Sociologie, histoire, anthropologie des dynamiques culturelles

Jacques Cheyronnaud, Élisabeth Claverie, chargés de recherche au CNRS Anthropologie des dispositifs cultuels Une première partie a été consacrée par J. Cheyronnaud à introduire à une anthropologie du christianisme en Europe et notamment, à traiter des risques d’une circularité conceptuelle s’agissant par exemple des termes de culte, rite et rituel, cérémonie : leur passage en réélaborations théologiques issues de lectures de travaux anthropologiques par exemple sur les questions de rituel ou ..

Isotopic control of the boron-vacancy spin defect in hexagonal boron nitride

We report on electron spin resonance (ESR) spectroscopy of boron-vacancy (V$_\text{B}^-$) centers hosted in isotopically-engineered hexagonal boron nitride (hBN) crystals. We first show that isotopic purification of hBN with $^{15}$N yields a simplified and well-resolved hyperfine structure of V$_\text{B}^-$ centers, while purification with $^{10}$B leads to narrower ESR linewidths. These results establish isotopically-purified h$^{10}$B$^{15}$N crystals as the optimal host material for future use of V$_\text{B}^-$ spin defects in quantum technologies. Capitalizing on these findings, we then demonstrate optically-induced polarization of $^{15}$N nuclei in h$^{10}$B$^{15}$N, whose mechanism relies on electron-nuclear spin mixing in the V$_\text{B}^-$ ground state. This work opens up new prospects for future developments of spin-based quantum sensors and simulators on a two-dimensional material platform.Comment: 6 pages, 3 figur

Transcriptome annotation using tandem SAGE tags

Analysis of several million expressed gene signatures (tags) revealed an increasing number of different sequences, largely exceeding that of annotated genes in mammalian genomes. Serial analysis of gene expression (SAGE) can reveal new Poly(A) RNAs transcribed from previously unrecognized chromosomal regions. However, conventional SAGE tags are too short to identify unambiguously unique sites in large genomes. Here, we design a novel strategy with tags anchored on two different restrictions sites of cDNAs. New transcripts are then tentatively defined by the two SAGE tags in tandem and by the spanning sequence read on the genome between these tagged sites. Having developed a new algorithm to locate these tag-delimited genomic sequences (TDGS), we first validated its capacity to recognize known genes and its ability to reveal new transcripts with two SAGE libraries built in parallel from a single RNA sample. Our algorithm proves fast enough to experiment this strategy at a large scale. We then collected and processed the complete sets of human SAGE tags to predict yet unknown transcripts. A cross-validation with tiling arrays data shows that 47% of these TDGS overlap transcriptional active regions. Our method provides a new and complementary approach for complex transcriptome annotation

Potential of Core-Collapse Supernova Neutrino Detection at JUNO

JUNO is an underground neutrino observatory under construction in Jiangmen, China. It uses 20kton liquid scintillator as target, which enables it to detect supernova burst neutrinos of a large statistics for the next galactic core-collapse supernova (CCSN) and also pre-supernova neutrinos from the nearby CCSN progenitors. All flavors of supernova burst neutrinos can be detected by JUNO via several interaction channels, including inverse beta decay, elastic scattering on electron and proton, interactions on C12 nuclei, etc. This retains the possibility for JUNO to reconstruct the energy spectra of supernova burst neutrinos of all flavors. The real time monitoring systems based on FPGA and DAQ are under development in JUNO, which allow prompt alert and trigger-less data acquisition of CCSN events. The alert performances of both monitoring systems have been thoroughly studied using simulations. Moreover, once a CCSN is tagged, the system can give fast characterizations, such as directionality and light curve

Detection of the Diffuse Supernova Neutrino Background with JUNO

As an underground multi-purpose neutrino detector with 20 kton liquid scintillator, Jiangmen Underground Neutrino Observatory (JUNO) is competitive with and complementary to the water-Cherenkov detectors on the search for the diffuse supernova neutrino background (DSNB). Typical supernova models predict 2-4 events per year within the optimal observation window in the JUNO detector. The dominant background is from the neutral-current (NC) interaction of atmospheric neutrinos with 12C nuclei, which surpasses the DSNB by more than one order of magnitude. We evaluated the systematic uncertainty of NC background from the spread of a variety of data-driven models and further developed a method to determine NC background within 15\% with {\it{in}} {\it{situ}} measurements after ten years of running. Besides, the NC-like backgrounds can be effectively suppressed by the intrinsic pulse-shape discrimination (PSD) capabilities of liquid scintillators. In this talk, I will present in detail the improvements on NC background uncertainty evaluation, PSD discriminator development, and finally, the potential of DSNB sensitivity in JUNO