11,579 research outputs found

    Evolution of correlation strength in KxFe(2-y)Se2 superconductor doped with S

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    We report the evolution of thermal transport properties of iron-based superconductor Kx_xFe2y_{2-y}Se2_2 with sulfur substitution at Se sites. Sulfur doping suppresses the superconducting TcT_c as well as the Seebeck coefficient. The Seebeck coefficient of all crystals in the low temperature range can be described very well by diffusive thermoelectric response model. The zero-temperature extrapolated value of Seebeck coefficient divided by temperature S/TS/T gradually decreases from 0.48μV/K2-0.48 \mu V/K^2 to a very small value \sim 0.03 μ\muV/K2^2 where TcT_c is completely suppressed. The normal state electron Sommerfeld term (γn\gamma_n) of specific heat also decreases with the increase of sulfur content. The dcrease of S/TS/T and γn\gamma_n reflects a suppression of the density of states at the Fermi energy, or a change in the Fermi surface that would induce the suppression of correlation strength.Comment: 5 Pages, 4 figures, 1 Table; submitted to Physical Review

    Systems, interactions and macrotheory

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    A significant proportion of early HCI research was guided by one very clear vision: that the existing theory base in psychology and cognitive science could be developed to yield engineering tools for use in the interdisciplinary context of HCI design. While interface technologies and heuristic methods for behavioral evaluation have rapidly advanced in both capability and breadth of application, progress toward deeper theory has been modest, and some now believe it to be unnecessary. A case is presented for developing new forms of theory, based around generic “systems of interactors.” An overlapping, layered structure of macro- and microtheories could then serve an explanatory role, and could also bind together contributions from the different disciplines. Novel routes to formalizing and applying such theories provide a host of interesting and tractable problems for future basic research in HCI

    Self monitoring of blood glucose - a survey of Diabetes UK members with type 2 diabetes who use SMBG

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    Background: aim - to survey members of Diabetes UK who had Type 2 diabetes and who used self monitoring of blood glucose (SMBG), to elicit their views on its usefulness in the management of their diabetes, and how they used the results. A questionnaire was developed for the Diabetes UK website. The questionnaire was posted on the Diabetes UK website until over 500 people had responded. Questions asked users to specify the benefits gained from SMBG, and how these benefits were achieved. We carried out both quantitative analysis and a thematic analysis for the open ended free-text questions.Findings: 554 participants completed the survey, of whom 289 (52.2%) were male. 20% of respondents were recently diagnosed (&lt; 6 months). Frequency of SMBG varied, with 43% of participants testing between once and four times a day and 22% testing less than once a month or for occasional periods.80% of respondents reported high satisfaction with SMBG, and reported feeling more 'in control' of their diabetes management using it. The most frequently reported use of SMBG was to make adjustments to food intake or confirm a hyperglycaemic episode.Women were significantly more likely to report feelings of guilt or self-chastisement associated with out of range readings (p = &lt; .001).Conclusion: SMBG was clearly of benefit to this group of confirmed users, who used the results to adjust diet, physical activity or medications. However many individuals (particularly women) reported feelings of anxiety and depression associated with its use.<br/

    Creation and luminescence of size-selected gold nanorods

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    Fluorescent metal nanoparticles have attracted great interest in recent years for their unique properties and potential applications. Their optical behaviour depends not only on size but also on shape, and will only be useful if the morphology is stable. In this work, we produce stable size-selected gold nanorods (aspect ratio 1-2) using a size-selected cluster source and correlate their luminescence behaviour with the particle shape. Thermodynamic modelling is used to predict the preferred aspect ratio of 1.5, in agreement with the observations, and confirms that the double-icosahedron observed in experiments is significantly lower in energy than the alternatives. Using these samples a fluorescence lifetime imaging microscopy study observed two photon luminescence from nanoparticle arrays and a fast decay process (<100 ps luminescence lifetime), which are similar to those found from ligand stabilized gold nanorods under the same measurement conditions, indicating that a surface plasmon enhanced two-photon excitation process is still active at these small sizes. By further reducing the nanoparticle size, this approach has the potential to investigate size-dependent luminescence behaviour at smaller sizes than has been possible before

    Oxidation Behavior of a Pd_(43)Cu_(27)Ni_(10)P_(20) Bulk Metallic Glass and Foam in Dry Air

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    The oxidation behavior of both Pd_(43)Cu_(27)Ni_(10)P_(20) bulk metallic glass (Pd4-BMG) and its amorphous foam containing 45 pct porosity (Pd4-AF) was investigated over the temperature range of 343 K (70 °C) to 623 K (350 °C) in dry air. The results showed that virtually no oxidation occurred in the Pd4-BMG at T < 523 K (250 °C), revealing the alloy’s favorable oxidation resistance in this temperature range. In addition, the oxidation kinetics at T ≥ 523 K (250 °C) followed a parabolic-rate law, and the parabolic-rate constants (k_p values) generally increased with temperature. It was found that the oxidation k_p values of the Pd4-AF are slightly lower than those of the Pd4-BMG, indicating that the porous structure contributes to improving the overall oxidation resistance. The scale formed on the alloys was composed exclusively of CuO at T ≥ 548 K (275 °C), whose thickness gradually increased with increasing temperature. In addition, the amorphous structure remained unchanged at T ≤ 548 K (275 °C), while a triplex-phase structure developed after the oxidation at higher temperatures, consisting of Pd_2Ni_2P, Cu_3P, and Pd_3P

    EVALUATING CHANGES IN TRAINING MANAGER’S ROLE PERCEPTIONS: A CASE STUDY OF TRHE NUCLEAR POWER INDUSTRY

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    Organizations are increasingly recognizing the importance of moving from training to performance improvement in Human Resource Development (HRD). Business organizations need to dramatically alter the roles of training managers to ensure that they move towards a performance improvement process, and to ensure that potential solutions are linked to organizational and individual performance problems. As part of a program for nuclear power managers at a major university, we evaluated the changes in the perceptions of twenty-one training managers from around the United States. The evaluation data lead us to conclusions regarding the changing role of training managers from strictly training to that of performance consultant and the challenges manger’s face as they try to build partnering relationships
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