37 research outputs found
Combined coherent x-ray micro-diffraction and local mechanical loading on copper nanocrystals
Coherent x-ray micro-diffraction and local mechanical loading can be combined
to investigate the mechanical deformation in crystalline nanostructures. Here
we present measurements of plastic deformation in a copper crystal of
sub-micron size obtained by loading the sample with an Atomic Force Microscopy
tip. The appearance of sharp features in the diffraction pattern, while
conserving its global shape, is attributed to crystal defects induced by the
tip
Environmental characterisation of retification process by-products (liquid and gaseous wastes)
6th International Symposium âEnvironment and Wood Preservationâ Cannes-Mandelieu, France 7-8 February 2005 14 pagesIn order to reduce environmental risks during the service life of the treated wood and to find new alternative developments on the durability of wood, some research and technology development have been made on thermal treatment. The retification process is one of these processes. The retification process induces chemical modification of the lignin and cellulosic components and modifies the intrinsic properties of wood : efficient increases the durability against fungi and insects, increases of the dimensional stability, decrease of the mechanical properties. The interest of this process is to reduce the environmental impact during the service life. In order to confirm the high interest of this process for the reduction of the environmental impact, an environmental characterisation of wastes on pilot plant have been carried out. Chemical analysis on gaseous and liquid effluents have been performed. An energetic assessment has been realised. The results indicate the high interest of this process in terms of possible biodegradable wastes and chemical valorisation interest, interest on energetic consumption in comparison with other wood processing treatment, interest on using retification treated wood in flooring according to indoor air quality requirements
Strain inhomogeneity in copper islands probed by coherent X-ray diffraction
International audienceThe strain field of individual epitaxial sub-micrometric copper islands is studied using coherent X-ray diffraction and finite element modelling. The strain inhomogeneity in each island is so large that the characteristic features of the island shape tend to disappear in the diffraction pattern, which is dominated by strain effects. The model confirms the tensile strain imposed to the island by the thermal mismatch occurring during the preparation of the samples. An evaluation of the residual strain is obtained by qualitatively fitting the diffraction data
High mean arterial pressure target to improve sepsis-associated acute kidney injury in patients with prior hypertension: a feasibility study
Background : The optimal mean arterial pressure (MAP) in cases of septic shock is still a matter of debate in patients with prior hypertension. An MAP between 75 and 85 mmHg can improve glomerular filtration rate (GFR) but its effect on tubular function is unknown. We assessed the effects of high MAP level on glomerular and tubular renal function in two intensive care units of a teaching hospital. Inclusion criteria were patients with a history of chronic hypertension and developing AKI in the first 24 h of septic shock. Data were collected during two 6 h periods of MAP regimen administered consecutively after haemodynamic stabilisation in an order depending on the patient's admission unit: a high-target period (80â85 mmHg) and a low-target period (65â70 mmHg). The primary endpoint was the creatinine clearance (CrCl) calculated from urine and serum samples at the end of each MAP period by the UV/P formula. Results : 26 patients were included. Higher urine output (+0.2 (95%:0, 0.4) mL/kg/h; Pâ=â0.04), urine sodium (+6 (95% CI 0.2, 13) mmol/L; Pâ=â0.04) and lower serum creatinine (ââ10 (95% CI ââ17, ââ3) ”mol/L; Pâ=â0.03) were observed during the high-MAP period as compared to the low-MAP period, resulting in a higher CrCl (+25 (95% CI 11, 39) mL/mn; Pâ=â0.002). The urine creatinine, urineâplasma creatinine ratio, urine osmolality, fractional excretion of sodium and urea showed no significant variation. The KDIGO stage at inclusion only interacted with serum creatinine variation and low level of sodium excretion at inclusion did not interact with these results. Conclusions : In the early stage of sepsis-associated AKI, a high-MAP target in patients with a history of hypertension was associated with a higher CrCl, but did not affect the kidneys' ability to concentrate urine, which may reflect no effect on tubular function
Modelisation d'hemoproteines: Cytochrome P-450, Chloroperoxydase et Lignine peroxydase. Modeles efficaces de Lignine peroxydase
SIGLEINIST T 70685 / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc
Rapport de mission : mise en route du Centre Semencier de Damien Ă Port au Prince en Haiti, 18 juin-10 juillet 1979
Le présent rapport est un compte rendu technique sur la mise en route du Centre semencier de Damien à Port au Prince en Hait
Qu'est-ce qu'un biosourcé? Normalisation, détermination du contenu biosourcé, enjeux pour le secteur bois
National audienc
Caractérisation des effets thermiques et des mécanismes de défaillance spécifiques aux transistors bipolaires submicroniques sur substrat InP dédiés aux transmissions optiques Ethernet à 112 Gb/s
Ces travaux de thÚses présentent un protocole expérimental d évaluation de la fiabilité des transistors bipolaire à double hétéro-jonction submicroniques sur substrat InP. Les mécanismes de défaillances observés ont été mis en évidence grùce à ce protocole qui présente trois étapes : activation, détection et localisation des mécanismes de défaillance. Les tests de vieillissement accéléré ont été réalisés sur les TBH de structure hexagonale avec une base en InGaAs ou en GaAsSb ainsi que les structures TLM. Grùce à l analyse électrique via la modélisation compacte, nous établissons les premiÚres hypothÚses sur l origine physique des mécanismes de dégradation. Pour les transistors avec une base InGaAs, par exemple, les mécanismes de défaillance mis en évidence sont localisés:- A la périphérie d émetteur entrainant ainsi une augmentation du courant de base pour VBE0,6 V et 0.20,8 V. Cette diminution du courant est plus visible sur le courant de collecteur.Ces hypothÚses ont été validées avec l analyse physique 2D avec le logiciel TCAD Sentaurus. Des signatures électriques similaires ont été observées dans la bibliographie par de plusieurs auteurs.This work presents the implementation of an experimental procedure to evaluate the failure mechanisms of submicron Heterojunction Bipolar Transistor on InP substrate. This procedure presents 3 steps: activation, detection and localization of the failure mechanisms. The accelerated aging tests have been used to active the failure mechanisms on hexagonal shape HBTs with InGaAs or GaAsSb base together with TLM. Due to the electrical analysis through the compact modelling, we established the first hypothesis about the origin of the failure mechanisms. For example, on InGaAs HBT, the failure mechanisms observed are located:- At the emitter sidewall. This mechanism leads to the increase of the base current for VBE0,6 V and 0.20.8 V.These hypotheses were validated by 2D physical simulation using TCAD Sentaurus. The same electrical signatures of the failure mechanisms are observed in literature.BORDEAUX1-Bib.electronique (335229901) / SudocSudocFranceF
Stereoselective synthesis of cyclometalated iridium(III) complexes: characterization and photophysical properties
The stereoselective synthesis of a highly luminescent neutral Ir(III) complex comprising two bidentate chiral, cyclometalating phenylpyridine derivatives, and one acetylacetonate as ligands is described. The final complex and some intermediates were characterized by X-ray structural analysis, NMR-, CD-, and CPL-spectroscopy