17,105 research outputs found

    Thermodynamic evidence for pressure-induced bulk superconductivity in the Fe-As pnictide superconductor CaFe2As2

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    We report specific-heat and resistivity experiments performed in parallel in a Bridgman-type of pressure cell in order to investigate the nature of pressure-induced superconductivity in the iron pnictide compound CaFe2As2. The presence of a pronounced specific-heat anomaly at Tc reveals a bulk nature of the superconducting state. The thermodynamic transition temperature differs dramatically from the onset of the resistive transition. Our data indicates that superconductivity occurs in the vicinity of a crystallographic phase transition. We discuss the discrepancy between the two methods as caused by strain-induced superconducting precursors formed above the bulk thermodynamic transition due to the vicinity of the structural instability

    Electron-doped phosphorene: A potential monolayer superconductor

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    We predict by first-principles calculations that the electron-doped phosphorene is a potential BCS-like superconductor. The stretching modes at the Brillouin-zone center are remarkably softened by the electron-doping, which results in the strong electron-phonon coupling. The superconductivity can be introduced by a doped electron density (n2Dn_{2D}) above 1.3×10141.3 \times10^{14} cm2^{-2}, and may exist over the liquid helium temperature when n2D>2.6×1014n_{2D}>2.6 \times10^{14} cm2^{-2}. The maximum critical temperature is predicted to be higher than 10 K. The superconductivity of phosphorene will significantly broaden the applications of this novel material

    Dynamic characteristics analysis of rolling mill gear reducer using nutation face gear transmission

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    The nutation face gear transmission system has advantages such as high reduction ratio, high power density, compact structure, and smooth transmission, making it suitable for high-power transmission in metallurgical machinery, tunnel boring machines, and other applications. In this study, a 12-degree-of-freedom bending-torsion-axial coupling dynamic model of the transmission system is established. The impact of mesh stiffness amplitude on the dynamic characteristics of the novel rolling mill gear reducer is considered. The research indicates that an increase in gear pair mesh stiffness leads to an increase in torsional vibration amplitude

    Optimización de un método acuoso para la producción de aceite de sésamo blanco de alta calidad y harina sin aceite

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    Research into the production of white sesame oil by aqueous extraction has been promoted because of concerns about the environment, health, and cost. The advanced aqueous method using a 1.95:10 liquid-to-raw material ratio, which was finally developed in this study, recovered 96.06% white sesame oil and produced de-oiled meal with high quality (3.98% residual oil content). The acid value and peroxide value of the oil produced were quite low at 0.19 mg KOH/kg and 90%). It can also be a nutritious ingredient or raw material for producing many food products.La investigación sobre la producción de aceite de sésamo blanco por extracción acuosa se ha promovido debido a las preocupaciones sobre el medio ambiente, la salud y el costo. El método acuoso avan­zado que utiliza una relación líquido-materia prima de 1,95:10, desarrollado en este estudio, recuperó un 96,06% de aceite de sésamo blanco y produjo harina sin aceite con alta calidad (3,98% de contenido de aceite residual). El valor de acidez y el índice de peróxido del aceite producido fueron bastante bajos, 0.19 mgKOH/kg y 90%). También puede ser un ingrediente nutritivo o materia prima para producir muchos productos alimenticios
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