2,556 research outputs found

    Tracking defect-induced ferromagnetism in GaN:Gd

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    We report on the magnetic properties of GaN:Gd layers grown by molecular beam epitaxy (MBE). A poor reproducibility with respect to the magnetic properties is found in these samples. Our results show strong indications that defects with a concentration of the order of 10^19 cm^-3 might play an important role for the magnetic properties. Positron annihilation spectroscopy does not support the suggested connection between the ferromagnetism and the Ga vacancy in GaN:Gd. Oxygen co-doping of GaN:Gd promotes ferromagnetism at room temperature and points to a role of oxygen for mediating ferromagnetic interactions in Gd doped GaN

    Compensating vacancy defects in Sn- and Mg-doped In 2O3

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    MBE-grown Sn- and Mg-doped epitaxial In2O3 thin-film samples with varying doping concentrations have been measured using positron Doppler spectroscopy and compared to a bulk crystal reference. Samples were subjected to oxygen or vacuum annealing and the effect on vacancy type defects was studied. Results indicate that after oxygen annealing the samples are dominated by cation vacancies, the concentration of which changes with the amount of doping. In highly Sn-doped In2O3, however, these vacancies are not the main compensating acceptor. Vacuum annealing increases the size of vacancies in all samples, possibly by clustering them with oxygen vacancies.Peer reviewe

    Spontaneous mediastinal haemorrhage linked with thymic carcinoma and myelodysplasia: a case report

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    We report an unusual sequence of clinico-pathological manifestations of myelodysplastic syndrome and thymic squamous cell carcinoma. A 77-year-old man with a two-month history of myelodysplastic syndrome was admitted with acute chest pain and shortness of breath. Radiological investigations revealed an anterior mediastinal mass, associated with mediastinal haemorrhage. The mass was excised via a standard median sternotomy and was found to be an infiltrating squamous cell carcinoma, which arose from a multilocular thymic cyst

    ERIGrid Holistic Test Description for Validating Cyber-Physical Energy Systems

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    Smart energy solutions aim to modify and optimise the operation of existing energy infrastructure. Such cyber-physical technology must be mature before deployment to the actual infrastructure, and competitive solutions will have to be compliant to standards still under development. Achieving this technology readiness and harmonisation requires reproducible experiments and appropriately realistic testing environments. Such testbeds for multi-domain cyber-physical experiments are complex in and of themselves. This work addresses a method for the scoping and design of experiments where both testbed and solution each require detailed expertise. This empirical work first revisited present test description approaches, developed a newdescription method for cyber-physical energy systems testing, and matured it by means of user involvement. The new Holistic Test Description (HTD) method facilitates the conception, deconstruction and reproduction of complex experimental designs in the domains of cyber-physical energy systems. This work develops the background and motivation, offers a guideline and examples to the proposed approach, and summarises experience from three years of its application.This work received funding in the European Community’s Horizon 2020 Program (H2020/2014–2020) under project “ERIGrid” (Grant Agreement No. 654113)

    Efficacy of Echium spp. water extracts as post-harvest grain protectants against Plodia interpunctella

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    Water extracts of three plant species of the genus Echium (E. italicum L., E. vulgare L. and E. rubrum Jacq.) were tested under laboratory conditions for their activity as potential post-harvest grain protectants against Plodia interpunctella (Hubner, 1813) (Lepidoptera: Pyralidae) larvae. Antioxidative activity and total phenolic, flavonoid and tannin contents in plant extracts were determined. The larvicidal assays were conducted with the local population of P. interpunctella from Central Serbia on kernels of Takovoanka winter wheat cultivar. The experiment was set as factorial 3x3x3x3 block design type. Three groups of larvae of different maturity were used. The larvae were exposed to three different concentrations of water extracts (1%, 2% and 5%) of three listed plant species. Mortality was registered daily during 96 hours and the efficacy was calculated using Schneider-Orelli's formula. The largest number of dead larvae was recorded in the treatment of 1% extract of E. italicum on youngest group, after 72 and 96 h. Extracts of E. vulgare and E. rubrum did not show high larvicidal effect
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