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褐飞虱在台风系统中的降落特征 被引量:4
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作者 王翠花 翟保平 《南京农业大学学报》 CAS CSCD 北大核心 2013年第6期30-36,共7页
为了揭示褐飞虱在台风影响期间的降落特征,选择了7年中发生在褐飞虱迁飞季节的9个台风,根据逐日灯诱褐飞虱资料、田间候报资料、美国国家环境预报中心/美国国家大气研究中心(NCEP/NCAR)的网格点气象再分析资料及中国地面实测降水资料,利... 为了揭示褐飞虱在台风影响期间的降落特征,选择了7年中发生在褐飞虱迁飞季节的9个台风,根据逐日灯诱褐飞虱资料、田间候报资料、美国国家环境预报中心/美国国家大气研究中心(NCEP/NCAR)的网格点气象再分析资料及中国地面实测降水资料,利用ArcGIS、GrADS软件对褐飞虱降虫区的气象要素分布特征进行了详细的比较分析。结果表明:1)褐飞虱降虫区随着台风移动路径的变化而变化,不同路径台风气象要素的结构特征对褐飞虱的降落具有决定意义;2)台风系统内的降虫区常位于风向气旋式切变的辐合气流区内,并常有强降水相伴,其中降落的褐飞虱虫量大、局地性强;3)台风外围的降虫区上空多为辐散气流并伴有小雨天气出现,降虫范围广;4)盛夏季节出现的台风会造成褐飞虱混迁现象的出现,由西南风和北风引起的降虫比例很高。 展开更多
关键词 褐飞虱 降落特征 台风 路径 气象要素
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Thin Emitter Structure Improved Turn-on Characteristics in RSD
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作者 梁琳 余岳辉 +1 位作者 周郁明 王璐 《Transactions of Tianjin University》 EI CAS 2008年第3期182-185,共4页
The thin emitter structure was introduced into reversely switched dynistor(RSD) to improve its turn-on characteristics. According to the analysis of turn-on condition, thin emitter structure is capable of reducing t... The thin emitter structure was introduced into reversely switched dynistor(RSD) to improve its turn-on characteristics. According to the analysis of turn-on condition, thin emitter structure is capable of reducing the extraction action for the triggering plasma layer P1 during turn-on process, and satisfying the requirement that triggering electric charge cannot be exhausted and therefore enables RSD to turn on uniformly. The on-state thin emitter RSD was equivalent to an asymmetric pin diode model. The simulation result shows that the forward voltage drop of RSD falls with the decrease of doping dose in p^+-emitter in a certain range, and when the doping concentration is extremely tow, the decrease of the width of p^+-emitter can obtain a tow forward voltage drop. Thin emitter RSD chips were made by sintering AI on n-Si. The test result shows that their turn-on process is uniform and the voltage drop is 7.5 V when the peak conversion current is 5 500 A. 展开更多
关键词 reversely switched dynistor(RSD) thin emitter turn-on characteristics SWITCH forward voltage drop
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