2,662 research outputs found

    Recent advances in synchrotron X-ray studies of the atomic structures of metal alloys in liquid state

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    Research into the atomic structures of metal materials in the liquid state, their dynamic evolution versus temperature until the onset of crystal nucleation has been a central research topic in condensed matter physics and materials science for well over a century. However, research and basic understanding of the atomic structures of liquid metals are far less than those in the solid state of the samecompositions. This review serves as a condensed collection of the most important research literature published so far in this field, providing a critical and focused review of the historical research development and progress in this field since the 1920s. In particular, the development of powerful synchrotron X-ray sources and the associated experimental techniques and sample environments for studying in-situ the atomic structures of different metallic systems. The key findings made in numerous pure metals and metallic alloysystems are critically reviewed and discussed with the focus on the results and new understandings of structural heterogeneities found inside a bulk liquids, at the liquid surface of liquids, and or at liquid-solid interfaces. The possible future directions of research and development on the most advanced experimental and modelling techniques are envisaged and briefly discussed as well

    Adaptation in face animacy perception:An event-related potential study

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    A real face differs from an artificial face mainly in the animacy. Nowadays, the perception boundaries between the real and artificial faces are becoming blurred in our life with the ubiquitous use of AI. Therefore, the perception of animacy causes increasing interests. Here, we used an adaptation paradigm to investigate the animacy perception in faces. We morphed a real and an artificial face to generate a continuum of face images, and asked participants to judge the animacy of those face images after they were exposed to a real face or an artificial face. We found that after adaptation to a real face, the subjects were apt to identify a subsequently ambiguous face to be inanimate, whereas after adaptation to an artificial face, the subjects were apt to identify a subsequently ambiguous face to be animate, i.e., the face animacy aftereffect (FAAE). We simultaneously recorded EEG during the task and analyzed the event-related potentials in response to the test faces, and found that adaptation to a face animacy suppressed the amplitude of LPP (late positive potential) and prolonged the latencies of N250r and LPP, in response to subsequent animacy-congruent faces. However, for subsequent animacy-incongruent faces, the amplitude was enhanced in LPP and the latencies were shortened in N250r and LPP. Those modulations of N250r and LPP activity act as a neural correlate of face animacy adaptation

    Rotation of Polarization Angle in Gamma-Ray Burst Prompt Phase-\uppercase\expandafter{\romannumeral2}. The Influence of The Parameters

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    In addition to the light curve and energy spectrum, polarization is also important for the study of Gamma-ray burst (GRB) prompt emission. Rotation of the polarization angle (PA) with time will cause depolarization of the time-integrated polarization degree. However, it is rarely studied before. Here, we use the magnetic reconnection model with a large-scale ordered aligned magnetic field in the emitting region to study the influence of the key parameters on the PA rotations. We find that half-opening angle of the jet θj\theta_{j}, the observational angle θV\theta_{V}, and the bulk Lorentz factor Γ\Gamma all have significant impacts on the PA rotations. For a fixed θjΓ0\theta_{j}\Gamma_{0} value (Γ0\Gamma_{0} is the normalization factor of Γ\Gamma), regardless of concrete θj\theta_{j} and Γ0\Gamma_{0} values, PA rotation within T90T_{90} (\trianglePA) remains roughly unchanged for a qθV/θjq\equiv\theta_{V}/\theta_{j} value. As θjΓ0\theta_{j}\Gamma_{0} value increases, the qq range for \trianglePA>10>10^{\circ} becomes smaller. The most significant PA rotation with \trianglePA90\thicksim90^{\circ} will happen when θjΓ0100\theta_{j}\Gamma_{0}\thicksim100 and 1.1q1.21.1\leq q\leq1.2. For the top-hat jet, observations of the PA rotation within T90T_{90} will imply a slightly off-axis observation.Comment: 9 pages, 7 figures, submitte
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