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阅读过程模式对英语阅读教学的启示 被引量:17
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作者 谢舫 《宜宾学院学报》 2002年第2期54-56,共3页
英语阅读论主要研究英语阅读过程及英语作为外语阅读教与学的一般规律。本文旨在通过介绍从下而上的模式 ,从上而下的模式和相互作用的模式这三种阅读过程模式 ,分析英语专业学生的学习现状 。
关键词 阅读模式 阅读教学 英语教学 阅读过程 高夫模式 古德曼模式 相互作用模式 元认知能力
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Corona noise model of high-voltage AC transmission lines and engineering applications
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作者 Wu Jiuhui Di Zelong 《Engineering Sciences》 EI 2013年第1期68-73,共6页
In order to predict the levels of corona noise from high-voltage alternating current (AC) transmission lines, the mechanism of corona noise and the corresponding theoretical prediction model are investigated. On the... In order to predict the levels of corona noise from high-voltage alternating current (AC) transmission lines, the mechanism of corona noise and the corresponding theoretical prediction model are investigated. On the basis of Drnde model, the motion of positive and negative ions produced by high-voltage corona is analyzed, and the mechanism of corona noise is discovered. The theoretical prediction model is put forward by using Kirchhoff formula, which is verified by the well agreement between our result and others' , considering the case of three- phase single lines. Moreover, the calculation results show that for both single and bundled lines, the sound pres- sure level of the typical frequency, i.e. twice the power frequency, attenuates slowly and leads to an obviously in- terferential phenomenon near the transmission lines, but the level of the bundled lines is smaller than that of the single ones under the same transmission voltage. Based on the mechanism of corona noise and the prediction model, it is obvious that bundled lines and/or increased line radius can be adopted to reduce corona noise in the practical engineering applications effectively. This model can also provide a theoretical guidance for the high-volt- age AC transmission line design. 展开更多
关键词 corona noise Drude model twice power frequency component Kirchhoff formula noise reduction
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