Characterization of the Evolution of IC Emissions after Accelerated Aging

9 pagesInternational audienceWith the evolving technological development of integrated circuits (ICs), ensuring electromagnetic compatibility (EMC) is becoming a serious challenge for electronic circuit and system manufacturers. Although electronic components must pass a set of EMC tests to ensure safe operations, the evolution over time of EMC is not characterized and cannot be accurately forecast. This paper presents an original study about the consequences of the aging of circuits on electromagnetic emission. Different types of standard applicative and accelerated-life tests are applied on a mixed power circuit dedicated to automotive applications. Its conducted emission is measured before and after these tests showing variations in EMC performances. Comparisons between each type of aging procedure show that the emission level of the circuit under test is affected differently

Ultrahigh-resolution crystallography and related electron density and electrostatic properties in proteins

Ultrahigh-resolution protein diffraction data allow valence electron density modelling and calculations of experimental electrostatic properties. Protein–ligand interaction energy may therefore be estimated

L’appropriation d’un outil d’intervention didactique pour l’analyse du travail

Les conseillers agricoles ont peu d’occasions d’échanger sur leur métier, même si ils échangent sur les dimensions les plus opérationnelles qui les affectent. Chercheurs et professionnels ont depuis plusieurs années, construits une dizaine de dispositifs d’échange entre pairs pour permettre aux conseillers de remettre à leur main les situations de travail qu’ils rencontrent et rediscuter les normes de métier. Pour cela, ils mobilisent un outil co-produit « l’Agroseil ». Cet outil propose une démarche d’analyse du travail au sein de ces dispositifs et peut alors constituer une ressource pour aider leur animateur à mettre en réflexion le collectif sur le métier. Nous analysons l’appropriation de cet outil par ces animateurs pour discuter des conditions qui leur permettre d’en faire un instrument d’intervention didactique sur le travail de conseil

PRIMERA COMUNIÓN [Material gráfico]

FOTO DE CHICO CON VELA EN LA MANO Y LAZO BLANCO EN EL BRAZO APOYADO EN RECLINATORIOCopia digital. Madrid : Ministerio de Educación, Cultura y Deporte. Subdirección General de Coordinación Bibliotecaria, 201

The molecular structure of melts along the carbonatite–kimberlite–basalt compositional joint: CO2and polymerisation

International audienceTransitional melts, intermediate in composition between silicate and carbonate melts, form by low degree partial melting of mantle peridotite and might be the most abundant type of melt in the asthenosphere. Their role in the transport of volatile elements and in metasomatic processes at the planetary scale might be significant yet they have remained largely unstudied. Their molecular structure has remained elusive in part because these melts are difficult to quench to glass. Here we use FTIR, Raman, 13C and 29Si NMR spectroscopy together with First Principle Molecular Dynamic (FPMD) simulations to investigate the molecular structure of transitional melts and in particular to assess the effect of CO2on their structure. We found that carbon in these glasses forms free ionic carbonate groups attracting cations away from their usual ‘depolymerising’ role in breaking up the covalent silicate network. Solution of CO2in these melts strongly modifies their structure resulting in a significant polymerisation of the aluminosilicate network with a decrease in NBO/Si of about 0.2 for every 5 mol% CO2dissolved.This polymerisation effect is expected to influence the physical and transport properties of transitional melts. An increase in viscosity is expected with increasing CO2content, potentially leading to melt ponding at certain levels in the mantle such as at the lithosphere–asthenosphere boundary. Conversely an ascending and degassing transitional melt such as a kimberlite would become increasingly fluid during ascent hence potentially accelerate. Carbon-rich transitional melts are effectively composed of two sub-networks:a carbonate and a silicate one leading to peculiar physical and transport properties