Plasmon-enhanced diffraction in nanoparticle gratings fabricated by in situ photo-reduction of gold chloride doped polymer thin films by laser interference patterning

International audienc

Etude microscopique et macroscopiques de la propriété anti-agglomérante de tensioactifs sur l’hydrate de cyclopentane.

COMInternational audienc

Experimental study of pyrolytic boron nitride at high temperature with and without proton and VUV irradiations

International audienceIn the frame of future exploration missions such as Solar Probe Plus (NASA) and PHOIBOS (ESA), research was carried out to study pyrolytic BN material envisaged as coating for their heat shields. The physico-chemical behavior of CVD pBN at very high temperature with or without hydrogen ions and VUV (Vacuum Ultra-Violet) irradiations was studied in high vacuum together with the in situ measurement of the thermal radiative properties conditioning the thermal equilibrium of the heat shield. Experimental results obtained on massive pBN samples are presented through in situ mass spectrometry and mass loss rate, and post-test microstructural characterization by XRD, SEM, AFM and nano-indentation techniques, some of them leading to mechanical properties. It could be concluded that synergistic effect of high temperature, protons and VUV radiation has an impact on the emission of gaseous species, the mass loss rate and the mechanical properties of the material

Influence of surface roughness and temperature on the oxidation behavior of ZrC/SiC samples

International audienceNew composites were elaborated using ZrC and SiC powders and the Spark Plasma Sintering process. The samples were polished at 4 different levels in order to compare the influence of surface roughness and temperature (1400 and 1600 K) on the characteristics of the oxide layers. By XRD analysis, it was confirmed that polishing and temperature level provoked changes in the crystalline structure. SEM imaging coupled to EDS microanalysis showed that the oxide layer was made of zirconia grains with silica at the grain boundaries. Nano-indentation was used to analyze the influence of the initial surface roughness and temperature on the hardness of the oxide layer. At 1400 K, the initial polishing has favored the growth of a hard oxide layer, which could be probably correlated to the higher crystallinity of the oxide. At 1600 K, it seems that a rougher initial surface favors the hardness of the oxide layer, which could be correlated to a better adherence between the oxide layer and the substrate. Both phenomena (crystallinity and adherence) would be in competition to reduce the fragility of the oxide layer.Do you want to read the rest of this article?Request full-tex

Antiagglomerant performance of surfactants evaluated in cyclopentane (CP) hydrate and CH4/C3H8 gas hydrate systems

AFFInternational audienc

High temperature oxidation of SiC under helium with low-pressure oxygen. Part 2: CVD β-SiC

International audienc

Anti-agglomerant performance of surfactants evaluated in cyclopentane hydrate and CH4/C3H8 gas hydrate systems.

ACTInternational audienc

HOT SUBTERRANEAN BIOSPHERE IN A CONTINENTAL OIL-RESERVOIR

THE presence of high concentrations of hyperthermophilic archaea in Alaskan oil fields has been attributed to viable hyperthermophiles in low concentrations in the injected sea water, but the existence of an indigenous community within the reservoir was ruled out(1). Here we present evidence for the existence of indigenous thermophilic bacteria and hyperthermophilic archaea from a continental petroleum reservoir about 1,670 m below the surface. The thermophilic isolates were repeatedly obtained from different wells and thrived in media similar to conditions in the wells, suggesting that these isolates are members of a deep indigenous thermophilic community. The unexpected presence of marine hyperthermophilic archaea in a deep continental environment extends the known ecological habitat of this group of organisms, and their unusual coexistence with terrestrial bacteria suggests that thermophiles may be widespread deep in the crust of the earth