Band offsets at zincblende-wurtzite GaAs nanowire sidewall surfaces

The band structure and the Fermi level pinning at clean and well-ordered sidewall surfaces of zincblende (ZB)-wurtzite (WZ) GaAs nanowires are investigated by scanning tunneling spectroscopy and density functional theory calculations. The WZ-ZB phase transition in GaAs nanowires introduces p-i junctions at the sidewall surfaces. This is caused by the presence of numerous steps, which induce a Fermi level pinning at different energies on the non-polar WZ and ZB sidewall facets.This study was financially supported by the EQUIPEX program Excelsior, the European Community’s Seventh Framework Program (Grant No. PITN-GA-2012- 316751, “Nanoembrace” Project) and the Impuls- und Vernetzungsfonds of the Helmholtz-Gemeinschaft Deutscher Forschungszentren under Grant No. HIRG-0014. T. Xu acknowledges the support from the National Natural Science Foundation of China (Grant No. 61204014)

Etude par choc laser de l'adhérence de barrières thermiques aéronautiques

National audienceL'estimation de la durée de vie des barrières thermiques aéronautiques (BT) déposées sur les aubes de turbines haute pression nécessite de comprendre les mécanismes induisant l'endommagement entre la sous-couche et la zircone. Le LASAT, LAser Shock Adhesion Test ou essai d'adhérence par choc laser, est une technique exploitant tout son potentiel dans le cas des BTs, en particulier par sa rapidité, simplicité et au comportement optique de la couche de zircone. Ce dernier avantage permet de dimensionner l'endommagement généré sans réaliser de coupes métallographiques. Un nouveau protocole de l'essai LASAT a été mis en place utilisant les ondes de choc bidimensionnelles et exploitant la dépendance entre l'intensité du choc appliqué, le niveau d'adhérence du dépôt, et la dimension de la fissure générée

Laser Shock Adhesion Test (LASAT) of electron beam physical vapor deposited thermal barrier coatings (EB-PVD TBCs)

International audienceDamage prediction, adhesion strength and remaining lifetime of TBC are highly important data for understanding and preventing TBC spallation on blades. LAser Shock Adhesion Test (LASAT) is a powerful method to measure adhesion of coating due to its rapidity, simplicity and capabilities to distinguish different strength levels and the easy damage observation in case of TBCs. A new protocol of LASAT has been introduced in order to measure the adhesion level of the ceramic coating from the exploitation of the two-dimensional effects that promotes a shock wave pressure-dependent size of the damage. Finite element modeling, taking into account the TBCs dimensions, showed the edges effect on interfacial stress applied by laser shock

Étude expérimentale de l’endommagement de composites sous choc LASER

Dans un contexte de mise en œuvre croissante des composites dans les secteurs aéronautiques et de la défense, la compréhension de leur comportement sous choc et de l’endommagement induit est un point crucial développé dans cette étude. Des LASER impulsionnels intenses sont mis en œuvre pour la génération d’impacts localisés et calibrés sur ces matériaux complexes, supportés par de nombreux diagnostics en temps réel et post-choc pour l’étude et la quantification de l’endommagement dynamique

A Small but Efficient Collaboration for the Spiral2 Control System Development

http://accelconf.web.cern.ch/AccelConf/ICALEPCS2013/papers/tucobab01.pdfThe Spiral2 radioactive ion beam facility to be commissioned in 2014 at Ganil (Caen) is built within international collaborations. This also concerns the control system development shared by three laboratories: Ganil has to coordinate the control and automated systems work packages, CEA/IRFU is in charge of the "injector" (sources and low energy beam lines) and the LLRF, CNRS/IPHC provides the emittancemeters and a beam diagnostics platform. Besides the technology Epics based, this collaboration, although being handled with a few people, nevertheless requires an appropriate and tight organization to reach the objectives given by the project. This contribution describes how, started in 2006, the collaboration for controls has been managed both from the technological point of view and the organizational one, taking into account not only the previous experience, technical background or skill of each partner, but also their existing working practices and "cultural" approaches. A first feedback comes from successful beam tests carried out at Saclay and Grenoble; a next challenge is the migration to operation, Ganil having to run Spiral2 as the other members are moving to new projects

Plume Impingement Analysis for the European Service Module Propulsion System

Plume impingement analyses were performed for the European Service Module (ESM) propulsion system Orbital Maneuvering System engine (OMS-E), auxiliary engines, and reaction control system (RCS) engines. The heat flux from plume impingement on the solar arrays and other surfaces are evaluated. This information is used to provide inputs for the ESM thermal analyses and help determine the optimal configuration for the RCS engines

Heart failure after treatment for breast cancer

Background: We aimed to develop dose–response relationships for heart failure (HF) following radiation and anthracyclines in breast cancer treatment, and to assess HF associations with trastuzumab and endocrine therapies. Methods and results: A case–control study was performed within a cohort of breast cancer survivors treated during 1980–2009. Cases (n = 102) had HF as first cardiovascular diagnosis and were matched 1:3 on age and date of diagnosis. Individual cardiac radiation doses were estimated, and anthracycline doses and use of trastuzumab and endocrine therapy were abstracted from oncology notes. For HF cases who received radiotherapy, the estimated median mean heart dose (MHD) was 6.8 Gy [interquartile range (IQR) 0.9–13.7]. MHD was not associated with HF risk overall [excess rate ratio (ERR) = 1%/Gy, 95% confidence interval (CI) −2 to 10]. In patients treated with anthracyclines, exposure of ≥20% of the heart to ≥20 Gy was associated with a rate ratio of 5.7 (95% CI 1.7–21.7) compared to <10% exposed to ≥20 Gy. For cases who received radiotherapy, median cumulative anthracycline dose was 247 mg/m2 (IQR 240–319). A dose-dependent increase was observed after anthracycline without trastuzumab (ERR = 1.5% per mg/m2, 95% CI 0.5–4.1). After anthracycline and trastuzumab, the rate ratio was 34.9 (95% CI 11.1–110.1) compared to no chemotherapy. Conclusions: In absence of anthracyclines, breast cancer radiotherapy was not associated with increased HF risk. Strongly elevated HF risks were observed after treatment with anthracyclines and also after treatment with trastuzumab. The benefits of these systemic treatments usually exceed the risks of HF, but our results emphasize the need to support ongoing efforts to evaluate preventative strategies