首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   54篇
  免费   1篇
天文学   55篇
  2024年   1篇
  2023年   1篇
  2019年   2篇
  2013年   1篇
  2010年   1篇
  2009年   7篇
  2008年   4篇
  2007年   8篇
  2006年   4篇
  2005年   7篇
  2004年   8篇
  2003年   7篇
  2002年   3篇
  2001年   1篇
排序方式: 共有55条查询结果,搜索用时 15 毫秒
1.
The interaction of carbon monoxide (CO) with vapour-deposited water(H2O) ices has been studied using temperature programmed desorption (TPD) and Fourier transform reflection-absorption infrared spectroscopy (FT-RAIRS) over a range of astrophysically relevant temperatures. Such measurements have shown that CO desorption from amorphous H2Oices is a much more complex process than current astrochemical models suggest. Re-visiting previously reported laboratory experiments (Collings et al., 2003), a rate model has been constructed to explain, in a phenomenological manner, the desorption of CO over astronomically relevant time scales. The model presented here can be widely applied to a range of astronomical environments where depletion of CO from the gas phase is relevant. The model accounts for the two competing processes of CO desorption and migration, and also enables the entrapment of some of the CO in the ice matrix and its subsequent release as the water ice crystallises and then desorbs. The astronomical implications of this model are discussed. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   
2.
3.
This paper reports results from an experiment designed to measure the nascent rovibrational population of H2 molecules that have formed through the heterogeneous recombination of H atoms on the surface of cosmic dust analogues under conditions approaching those of the interstellar medium (ISM). H2 that has formed on a highly oriented pyrolytic graphite (HOPG) surface has been detected, using laser induced resonance-enhanced multi-photon ionization (REMPI), in the v = 1 (J= 0–3) rovibrational states at surface temperatures of 30 K and 50 K. These excited product molecules display rotational temperatures significantly higher than the target surface temperature. These first results suggest that a considerable proportion of the binding energy released on formation of the H2 is deposited in the surface, in addition to internal excitation of the product molecules. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   
4.
The evolution of the universe from times after the recombination of the first atoms is controlled by chemistry. Chemistry can also help us to learn more about the first structures. In this paper we review the chemistry and atomic physics that are important in the time shortly after recombination, including the formation of the first structures. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   
5.
6.
太阳系早期的短寿期放射性核素   总被引:2,自引:0,他引:2  
徐伟彪 《天文学报》2003,44(3):231-239
较详细地介绍全新的太阳系起源理论——X-wind模式,天体化学实验发现太阳系早期存在大量的短寿期放射性核素(半衰期小于100Ma),这些核素对太阳系的形成和演化有重要的影响,一种理论认为,这些核素是在恒星内部合成,并由星风注入原太阳分子云,星风产生的激波诱发分子云核的塌缩而形成原太阳,另一种理论认为,这些核素是高能粒子与原太阳分子云或太阳星云中的气体和尘埃相互作用的产物。  相似文献   
7.
8.
9.
10.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号