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黄土高原台原阶地乾县试区干湿气候分析 被引量:1
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作者 寸待贵 《干旱地区农业研究》 CSCD 北大核心 1990年第3期31-37,共7页
黄土高原台原阶地乾县试区,位于渭北旱腰带南缘。地多深切沟壑。依据实测和调查,分析研究了试区的降水量、蒸发量、蒸发力、干燥度、水土流失、墒情旱情等资料。试区降水年际年内分布不均,多年平均年降水量为 584.2mm,最少年为 281.9mm... 黄土高原台原阶地乾县试区,位于渭北旱腰带南缘。地多深切沟壑。依据实测和调查,分析研究了试区的降水量、蒸发量、蒸发力、干燥度、水土流失、墒情旱情等资料。试区降水年际年内分布不均,多年平均年降水量为 584.2mm,最少年为 281.9mm;蒸发量较邻近气象站大,涵蓄水分能力差,地下水埋深超过 100m,水浇地只占耕地面积的6.8%,是个易旱区。农业用水主要靠自然降水,农业产量丰歉不稳,应重视做好合理开发利用,以发挥较大的生产潜力。 展开更多
关键词 干湿气候分析 黄土高原 台原阶地
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Marked Advance in Widths and Heights of Harmonic Plateau
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作者 陈高 朱颀人 《Communications in Theoretical Physics》 SCIE CAS CSCD 2010年第4期759-763,共5页
We propose a scheme to simultaneously widen and heighten the high-order harmonic plateau on a large scale. More specifically, by adopting a united two-atom system with a suitable inter-nuclear separation instead of a ... We propose a scheme to simultaneously widen and heighten the high-order harmonic plateau on a large scale. More specifically, by adopting a united two-atom system with a suitable inter-nuclear separation instead of a single-atom, the harmonic plateau is widened from Ip + 3.2Up to Ip +8.5Up; further, by adopting the combined pulse, the extended plateau (harmonics near Ip+ 5.6Up) is selectively heightened in excess of 4 orders of magnitude compared with the case of the low-frequency pulse alone. By means of the wavelet transform for the induced dipole of these harmonics, a single x-ray pulse as short as 210 asec is achieved. 展开更多
关键词 high-order harmonic generation united two-atom model combined pulse
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