23 research outputs found

    First-principles study on the electronic, optical, and transport properties of monolayer α- and β-GeSe

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    The extraordinary properties and the novel applications of black phosphorene induce the research interest in the monolayer group-IV monochalcogenides. Here using first-principles calculations, we systematically investigate the electronic, transport, and optical properties of monolayer alpha- and beta-GeSe, revealing a direct band gap of 1.61 eV for monolayer alpha-GeSe and an indirect band gap of 2.47 eV for monolayer beta-GeSe. For monolayer beta-GeSe, the electronic/hole transport is anisotropic, with an extremely high electron mobility of 2.93 x 10(4) cm(2)/Vs along the armchair direction, comparable to that of black phosphorene. Furthermore, for beta-GeSe, robust band gaps nearly independent of the applied tensile strain along the armchair direction are observed. Both monolayer aand beta-GeSe exhibit anisotropic optical absorption in the visible spectrum

    Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study

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    Funder: European Society of Intensive Care Medicine; doi: http://dx.doi.org/10.13039/501100013347Funder: Flemish Society for Critical Care NursesAbstract: Purpose: Intensive care unit (ICU) patients are particularly susceptible to developing pressure injuries. Epidemiologic data is however unavailable. We aimed to provide an international picture of the extent of pressure injuries and factors associated with ICU-acquired pressure injuries in adult ICU patients. Methods: International 1-day point-prevalence study; follow-up for outcome assessment until hospital discharge (maximum 12 weeks). Factors associated with ICU-acquired pressure injury and hospital mortality were assessed by generalised linear mixed-effects regression analysis. Results: Data from 13,254 patients in 1117 ICUs (90 countries) revealed 6747 pressure injuries; 3997 (59.2%) were ICU-acquired. Overall prevalence was 26.6% (95% confidence interval [CI] 25.9–27.3). ICU-acquired prevalence was 16.2% (95% CI 15.6–16.8). Sacrum (37%) and heels (19.5%) were most affected. Factors independently associated with ICU-acquired pressure injuries were older age, male sex, being underweight, emergency surgery, higher Simplified Acute Physiology Score II, Braden score 3 days, comorbidities (chronic obstructive pulmonary disease, immunodeficiency), organ support (renal replacement, mechanical ventilation on ICU admission), and being in a low or lower-middle income-economy. Gradually increasing associations with mortality were identified for increasing severity of pressure injury: stage I (odds ratio [OR] 1.5; 95% CI 1.2–1.8), stage II (OR 1.6; 95% CI 1.4–1.9), and stage III or worse (OR 2.8; 95% CI 2.3–3.3). Conclusion: Pressure injuries are common in adult ICU patients. ICU-acquired pressure injuries are associated with mainly intrinsic factors and mortality. Optimal care standards, increased awareness, appropriate resource allocation, and further research into optimal prevention are pivotal to tackle this important patient safety threat

    Prediction of Dissolved Impurities and Movement of Oxide Particles in the Primary Circuit of LBE Fast Reactor

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    To better understand the corrosion and corrosion products behavior in the primary circuit of lead-bismuth eutectic (LBE) coolant reactor, the concentration distribution of soluble impurities and the transport of solid particles are investigated through the finite-element method. An axisymmetric model of the primary circuit of an LBE reactor was constructed to accelerate the calculation of the thermal hydraulic filed of the circuit. The saturation concentration of solute Fe, Cr and Ni in LBE coolant are identified through the equilibrium of their oxides and PbO, and the very different saturation concentrations of Fe/Cr/Ni in LBE will lead to significant element-selective corrosion. The migration of solid oxide particles in the primary circuit is also investigated by the Euler–Lagrange tracing model. The simulation shows that driving force for the movement of particles >100 μm is buoyancy, which lets particles float on a free surface, while particles <10 μm tend to suspend in coolant. However, the behavior of particles also depends on the formation position, the particles formed above the core have a high possibility of re-entering in the core

    First-principles study on the electronic, optical, and transport properties of monolayer α- and β-GeSe

    No full text
    The extraordinary properties and the novel applications of black phosphorene induce the research interest in the monolayer group-IV monochalcogenides. Here using first-principles calculations, we systematically investigate the electronic, transport, and optical properties of monolayer alpha- and beta-GeSe, revealing a direct band gap of 1.61 eV for monolayer alpha-GeSe and an indirect band gap of 2.47 eV for monolayer beta-GeSe. For monolayer beta-GeSe, the electronic/hole transport is anisotropic, with an extremely high electron mobility of 2.93 x 10(4) cm(2)/Vs along the armchair direction, comparable to that of black phosphorene. Furthermore, for beta-GeSe, robust band gaps nearly independent of the applied tensile strain along the armchair direction are observed. Both monolayer aand beta-GeSe exhibit anisotropic optical absorption in the visible spectrum.</p

    First-principles study on the electronic, optical, and transport properties of monolayer alpha- and beta-GeSe

    No full text
    The extraordinary properties and the novel applications of black phosphorene induce the research interest in the monolayer group-IV monochalcogenides. Here using first-principles calculations, we systematically investigate the electronic, transport, and optical properties of monolayer alpha- and beta-GeSe, revealing a direct band gap of 1.61 eV for monolayer alpha-GeSe and an indirect band gap of 2.47 eV for monolayer beta-GeSe. For monolayer beta-GeSe, the electronic/hole transport is anisotropic, with an extremely high electron mobility of 2.93 x 10(4) cm(2)/Vs along the armchair direction, comparable to that of black phosphorene. Furthermore, for beta-GeSe, robust band gaps nearly independent of the applied tensile strain along the armchair direction are observed. Both monolayer aand beta-GeSe exhibit anisotropic optical absorption in the visible spectrum
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