66,339 research outputs found

    Structural synthesis for broken strands repair operation metamorphic mechanism of EHV transmission lines

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    Special operation requirements are needed for repositing broken strands of extra-high-voltage (EHV) power transmission lines before repairing. Metamorphic mechanism is applied to satisfy the requirements and a novel structural synthesis method is proposed, considering the forms and structures of constrained metamorphic joints. Metamorphic cyclogram and equivalent resistance gradient matrix of metamorphic joints are obtained by analyzing the repairing operation. Meanwhile, the source metamorphic mechanism with structure of non-constrained metamorphic joints is selected. Constrained form/structure matrix of metamorphic joints is built according to metamorphic cyclogram and equivalent resistance gradient matrix. The relation between constraint force changes of joints and form/structure of metamorphic joints is then obtained; and all the eight corresponding structures of constrained metamorphic mechanism are synthesized. One of the eight mechanisms is chosen as the broken strands reposition metamorphic mechanism, and its topological transformations of working configuration are analyzed to verify the feasibility and practicality of structural synthesis method proposed in this paper

    Structural Synthesis and Configuration Analysis of Broken Strands Repair Operation Metamorphic Mechanism

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    Appling metamorphic mechanism to satisfy the special operation requirements of the reposition before repairing operation for broken strands of extra-high-voltage (EHV) power transmission lines, a novel structural synthesis method of metamorphic mechanism is proposed considering the forms and structures of constrained metamorphic joints. According to the metamorphic cyclogram and the equivalent resistance gradient matrix, constrained form/structure matrix of metamorphic joints is built, the relation with constraint force changes of joints and form/structure of metamorphic joints is obtained; and further all the eight corresponding structures of constrained metamorphic mechanism are synthesized by the method. One of the eight mechanisms is chosen as the broken strands reposition metamorphic mechanism, and its topological transformations of working configuration are analyzed to verify the feasibility and practicality of structural synthesis method proposed in this paper

    Synthesis, Structure and Magnetic Properties of New Layered Iron-Oxychalcogenide Na2Fe2OSe2

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    A new layered iron-oxychalcogenide Na2Fe2OSe2 has been synthesized and structurally characterized by powder X-ray diffraction. The structure is formed by alternate stacking of the newly discovered [Fe2OSe2] blocks and double layers of Na. Conductivity study shows that Na2Fe2OSe2 is a semiconductor with activation energy of 0.26 eV. Magnetic susceptibility and heat capacity measurements reveal an antiferromagnetic phase transition occurs at TN=73 K. A broad maximum of magnetic susceptibility and a slow decay of the specific heat above TN, arises as a result of two-dimensional short-range spin correlation.Comment: 4 pages, 4 figure

    Microstructure and Fe-vacancy ordering in the KFexSe2 superconducting system

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    Structural investigations by means of transmission electron microscopy (TEM) on KFexSe2 with 1.5 \leq x \leq 1.8 have revealed a rich variety of microstructure phenomena, the KFe1.5Se2 crystal often shows a superstructure modulation along the [310] zone-axis direction, this superstructure can be well interpreted by the Fe-vacancy order within the a-b plane. Increase of Fe-concentration in the KFexSe2 materials could not only result in the appearance of superconductivity but also yield clear alternations of microstructure. Structural inhomogeneity, the complex superstructures and defect structures in the superconducting KFe1.8Se2 sample have been investigated based on the high-resolution TEM.Comment: 13 pages, 4 figure

    A general framework for learning prosodic-enhanced representation of rap lyrics

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    © 2019, Springer Science+Business Media, LLC, part of Springer Nature. Learning and analyzing rap lyrics is a significant basis for many Web applications, such as music recommendation, automatic music categorization, and music information retrieval, due to the abundant source of digital music in the World Wide Web. Although numerous studies have explored the topic, knowledge in this field is far from satisfactory, because critical issues, such as prosodic information and its effective representation, as well as appropriate integration of various features, are usually ignored. In this paper, we propose a hierarchical attention variational a utoe ncoder framework (HAVAE), which simultaneously considers semantic and prosodic features for rap lyrics representation learning. Specifically, the representation of the prosodic features is encoded by phonetic transcriptions with a novel and effective strategy (i.e., rhyme2vec). Moreover, a feature aggregation strategy is proposed to appropriately integrate various features and generate prosodic-enhanced representation. A comprehensive empirical evaluation demonstrates that the proposed framework outperforms the state-of-the-art approaches under various metrics in different rap lyrics learning tasks
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