3,967 research outputs found

    Use of thermodynamic properties of metal-gas systems as low-pressure standards

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    Modified version of Sievert's apparatus accurately calibrates low pressure measuring instruments. Metal-gas system is composed of hydrogen in two-phase equilibrium with erbium to obtain reproducible hydrogen pressures

    A study of metal oxygen and metal nitrogen systems for use as reduced pressure standards

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    Metal-oxygen and metal-nitrogen systems for use as reduced pressure standards using Sieverts apparatu

    The RHIC Zero Degree Calorimeter

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    High Energy collisions of nuclei usually lead to the emission of evaporation neutrons from both ``beam'' and ``target'' nuclei. At the RHIC heavy ion collider with 100GeV/u beam energy, evaporation neutrons diverge by less than  2~2 milliradians from the beam axis Neutral beam fragments can be detected downstream of RHIC ion collisions (and a large aperture Accelerator dipole magnet) if θ\theta\leq 4 mr but charged fragments in the same angular range are usually too close to the beam trajectory. In this 'zero degree' region produced particles and other secondaries deposit negligible energy when compared with that of beam fragmentation neutrons. The purpose of the RHIC zero degree calorimeters (ZDC's) is to detect neutrons emitted within this cone along both beam directions and measure their total energy (from which we calculate multiplicity). The ZDC coincidence of the 2 beam directions is a minimal bias selection of heavy ion collisions. This makes it useful as an event trigger and a luminosity monitor\cite{baltz} and for this reason we built identical detectors for all 4 RHIC experiments. The neutron multiplicity is also known to be correlated with event geometry \cite{appel} and will be used to measure collision centrality in mutual beam int eractions.Comment: 18 pages, 12 figure

    Analytic continuation by averaging Pad\'e approximants

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    The ill-posed analytic continuation problem for Green's functions and self-energies is investigated by revisiting the Pad\'{e} approximants technique. We propose to remedy the well-known problems of the Pad\'{e} approximants by performing an average of several continuations, obtained by varying the number of fitted input points and Pad\'{e} coefficients independently. The suggested approach is then applied to several test cases, including Sm and Pr atomic self-energies, the Green's functions of the Hubbard model for a Bethe lattice and of the Haldane model for a nano-ribbon, as well as two special test functions. The sensitivity to numerical noise and the dependence on the precision of the numerical libraries are analysed in detail. The present approach is compared to a number of other techniques, i.e. the non-negative least-square method, the non-negative Tikhonov method and the maximum entropy method, and is shown to perform well for the chosen test cases. This conclusion holds even when the noise on the input data is increased to reach values typical for quantum Monte Carlo simulations. The ability of the algorithm to resolve fine structures is finally illustrated for two relevant test functions.Comment: 10 figure

    High Q gallium nitride microring resonators

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    Controlled dephasing of Andreev states in superconducting quantum point-contacts

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    We have studied the relaxation and dephasing processes in a superconducting quantum point contact induced by the interaction with an electromagnetic environment. Based on a density matrix approach we obtain the rates for the dissipative dynamics as function of the transmission, the phase difference on the contact and the external impedance. Our calculation allows to determine the appropriate range of parameters for the observation of coherent oscillations in the current through the contact.Comment: 8 pages, 2 figures. To appear in Physical Review

    "I'd been like freaking out the whole night": exploring emotion regulation based on junior doctors' narratives

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    The importance of emotions within medical practice is well documented. Research suggests that how clinicians deal with negative emotions can affect clinical decision-making, health service delivery, clinician well-being, attentiveness to patient care and patient satisfaction. Previous research has identified the transition from student to junior doctor (intern) as a particularly challenging time. While many studies have highlighted the presence of emotions during this transition, how junior doctors manage emotions has rarely been considered. We conducted a secondary analysis of narrative data in which 34 junior doctors, within a few months of transitioning into practice, talked about situations for which they felt prepared or unprepared for practice (preparedness narratives) through audio diaries and interviews. We examined these data deductively (using Gross’ theory of emotion regulation: ER) and inductively to answer the following research questions: (RQ1) what ER strategies do junior doctors describe in their preparedness narratives? and (RQ2) at what point in the clinical situation are these strategies narrated? We identified 406 personal incident narratives: 243 (60%) contained negative emotion, with 86 (21%) also containing ER. Overall, we identified 137 ER strategies, occurring prior to (n = 29, 21%), during (n = 74, 54%) and after (n = 34, 25%) the situation. Although Gross’ theory captured many of the ER strategies used by junior doctors, we identify further ways in which this model can be adapted to fully capture the range of ER strategies participants employed. Further, from our analysis, we believe that raising medical students
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