The gravitational wave detector VIRGO

International audienc

The Virgo data acquisition system

International audienc

The SPIRAL radioactive ion beam facility

This document describes the scientific goals as well as the technical choices of the SPIRAL project (Système de Production d'Ions Radioactifs et d'Accélération en Ligne)

Large expert-curated database for benchmarking document similarity detection in biomedical literature search

Document recommendation systems for locating relevant literature have mostly relied on methods developed a decade ago. This is largely due to the lack of a large offline gold-standard benchmark of relevant documents that cover a variety of research fields such that newly developed literature search techniques can be compared, improved and translated into practice. To overcome this bottleneck, we have established the RElevant LIterature SearcH consortium consisting of more than 1500 scientists from 84 countries, who have collectively annotated the relevance of over 180 000 PubMed-listed articles with regard to their respective seed (input) article/s. The majority of annotations were contributed by highly experienced, original authors of the seed articles. The collected data cover 76% of all unique PubMed Medical Subject Headings descriptors. No systematic biases were observed across different experience levels, research fields or time spent on annotations. More importantly, annotations of the same document pairs contributed by different scientists were highly concordant. We further show that the three representative baseline methods used to generate recommended articles for evaluation (Okapi Best Matching 25, Term Frequency-Inverse Document Frequency and PubMed Related Articles) had similar overall performances. Additionally, we found that these methods each tend to produce distinct collections of recommended articles, suggesting that a hybrid method may be required to completely capture all relevant articles. The established database server located at https://relishdb.ict.griffith.edu.au is freely available for the downloading of annotation data and the blind testing of new methods. We expect that this benchmark will be useful for stimulating the development of new powerful techniques for title and title/abstract-based search engines for relevant articles in biomedical research.Peer reviewe

ON THE GROWTH FROM THE AMORPHOUS PHASE IN SEMICONDUCTORS

On développe un modèle de croissance d'une phase ordonnée basé sur la diffusion des lacunes thermiques produites à l'interface avec l'amorphe. Il fournit pour Ge et Si la dépendance exacte du taux de croissance pour les couches évaporées et les couches implantées avec la température, l'état de l'orientation cristallin, le dopage, l'ionisation et la nature des ions implantés.A model of growth based on the diffusion of thermally generated vacancies to the interface is developed which provides the exact dependence of the growth rate with temperature, crystalline orientation, doping, ionisation and nature of implanted ions in evaporated as well as implanted layers, for both Ge and Si

A critical look at EL2 models

A critical discussion of the experimental observations made on the EL2 defect in GaAs is made which allows us to conclude that the most probable configuration of this defect is the As antisite-As interstitial pair.Nous faisons une discussion critique des observations expérimentales faites sur EL2, ce qui nous amène à conclure que la configuration la plus probable de ce défaut est la paire As antisite-As interstitiel

Threshold energy for atomic displacement in electron irradiated germanium

n-type germanium has been irradiated with electrons of various energies in the range 0.5 to 3 MeV. Using transient capacitance measurements we observed four majority carrier traps associated with levels at 0.27 eV (E1), 0.39 eV (E2), 0.35 eV (E4), 0.32 eV (E5) below the conduction band. We have studied the variations of the introduction rates of these traps with the energy of irradiation. These variations are found to correspond to a threshold energy for atomic displacement of 20 ± 5 eV for the E 1 and E2 traps and of 40 ± 10 eV for the E 4 and E5 traps. It is concluded that the E 1 and E2 traps are associated with vacancy-or interstitial-type defects (association of a vacancy or of an interstitial with an impurity) while the E4 and E5 traps are associated with the divacancy

Electronic properties of grain boundaries in semiconductors

The aim of this communication is to describe the main results which we have obtained in the past years on the electronic properties of grain boundaries in semiconductors. The study, experimental as well as theoretical, has focused on the main electronic characteristics i.e. density of states, optical cross sections, carrier capture cross sections (and recombination velocity) from which all the other electronic properties can be derived. The experimental results concern mostly Ge and Si bicrystals although some experiments were performed in poly-Si. Since the results obtained are rather numerous and detailed in publications, here we discuss them briefly, focusing on the leading idea with connects them.Le but de cette communication est la description des résultats principaux que nous avons obtenus ces dernières années sur les propriétés électroniques des joints de grain dans les semiconducteurs. L'étude, expérimentale et théorique, était centrée sur les principales caractéristiques électroniques, à savoir la densité d'états, les sections de capture optique, les sections de capture pour les porteurs (et la vitesse de recombinaison) à partir desquelles toutes les propriétés électroniques peuvent être déduites. Les résultats expérimentaux concernent principalement les bicristaux de Ge et Si bien que quelques expériences aient été faites sur du Si polycristallin. Comme les résultats obtenus sont en nombre important et détaillés dans des publications, on les discute ici brièvement en mettant l'accent sur l'idée directrice qui les sous-tend