排序方式: 共有55条查询结果,搜索用时 15 毫秒
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采用分光计和光栅对太阳光谱进行观测,通过分光计的准直管使极窄的一束太阳光通过空间频率为1 200mm-1的闪耀光栅,在望远镜处观察到了若干条夫琅禾费线,测出了典型谱线的波长.通过分析光谱照片及分光计成像光路,利用几何关系及光学公式得到了亚纳米量级谱宽观测方法,并对典型夫琅禾费线宽进行了估算大致确定了夫琅禾费线的谱宽的范围. 相似文献
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在传统的采购思想中,人们对采购的理解往往局限于"购买"和轻松的"花钱办事",从而缺乏对采购需求的分析、采购布局等等。在通信行业高速发展的今天,采购正在作为一个独立的行业走向市场的前台,高效的采购对于企业优化运作、控制成本、加速资金周转和提高经营质量以及持续赢利等方面至关重要。随着规模效益的推动,采购活动占企业经营活动的比重大大增加,采购的作用被提升到了一个新的高度,采购精细化成为现代企业谋求发展壮大的必然要求。 相似文献
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In the framework of the time-dependent local density approximation, applied to valence electrons, coupled non- adiabatically to molecular dynamics of ions, we investigate the microscopic mechanism of collisions between low energetic protons and ethylene. Not only the amount of energy lost by the projectile, but also the electronic and vibronic excitations of the target are identified. We dynamics of the target depends sensitively on the impact find that the energy loss of the proton and excitation energy. 相似文献
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Using the time dependent local density approximation, applied to valence electrons, coupled non-adiabatically to molecular dynamics of ions, the collision process between ethylene and fast charged projectiles is studied in the microscopic way. The impact of ionic motion on the ionization is explored to show the importance of treating electronic and ionic degrees of freedom simultaneously. The number of escaped electrons, ionization probabilities are obtained. Furthermore, it is found that the ionic extensions in different directions show the different patterns. 相似文献
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