101,036 research outputs found

    Effect of Dzyaloshinskii Moriya interaction on magnetic vortex

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    The effect of the Dzyaloshinskii Moriya interaction on the vortex in magnetic microdisk was investigated by micro magnetic simulation based on the Landau Lifshitz Gilbert equation. Our results show that the DM interaction modifies the size of the vortex core, and also induces an out of plane magnetization component at the edge and inside the disk. The DM interaction can destabilizes one vortex handedness, generate a bias field to the vortex core and couple the vortex polarity and chirality. This DM-interaction-induced coupling can therefore provide a new way to control vortex polarity and chirality

    On practical design for joint distributed source and network coding

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    This paper considers the problem of communicating correlated information from multiple source nodes over a network of noiseless channels to multiple destination nodes, where each destination node wants to recover all sources. The problem involves a joint consideration of distributed compression and network information relaying. Although the optimal rate region has been theoretically characterized, it was not clear how to design practical communication schemes with low complexity. This work provides a partial solution to this problem by proposing a low-complexity scheme for the special case with two sources whose correlation is characterized by a binary symmetric channel. Our scheme is based on a careful combination of linear syndrome-based Slepian-Wolf coding and random linear mixing (network coding). It is in general suboptimal; however, its low complexity and robustness to network dynamics make it suitable for practical implementation

    Two-phase flow dynamics in the gas diffusion layer of proton exchange membrane fuel cells: Volume of fluid modeling and comparison with experiment

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    This paper proposes a three-dimensional (3D) volume of fluid (VOF) study to investigate two-phase flow in the gas diffusion layer (GDL) of proton exchange membrane (PEM) fuel cells and liquid water distribution. A stochastic model was adopted to reconstruct the 3D microstructures of Toray carbon papers and incorporate the experimentally-determined varying porosity. The VOF predictions were compared with the water profiles obtained by the X-ray tomographic microscopy (XTM) and the Leverett correlation. It was found local water profiles are similar in the sample’s sub-regions under the pressure difference p = 1000 Pa between the two GDL surfaces, but may vary significantly under p = 6000 Pa. The water-air interfaces inside the GDL structure were presented to show water distribution and breakthrough
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