排序方式: 共有5条查询结果,搜索用时 0 毫秒
1
1.
黄酮类化合物的质谱研究陈俊杰,李裕林(厦门大学化学系)(兰州大学有机化学研究所)黄酮类化合物是植物最普通的成分之一,是色原烷或色原酮的衍生物.其结构特点是具有C6-C3-C6的基本骨架,并可根据中间吡喃环的不同氧化水平和两侧A、B环上连接的各种取代基... 相似文献
2.
根据分形几何学理论,研究了岩石爆破块度的分形特征。认为,一直困扰我们的由岩石特性引起的爆破成缝的随机性,不规则性和爆破块度分布的复杂性,可由分形研究开创一个新的生长点。 相似文献
3.
4.
地空导弹单发杀伤概率之解析算法 总被引:1,自引:0,他引:1
在地空导弹杀伤区内的各空域点上,制导误差系统分量的存在是一个普遍的客观事实。计算这种情况下的单发杀伤概率更具有实际意义,然而这种计算通常要用数值积分去完成,这给理论分析和实际应用造成了不便。提供了导弹单发杀伤概率的一种解析算法,从而为其在理论分析和工程实践中的方便应用奠定了基础。 相似文献
5.
《Journal of Natural History》2012,46(11):2173-2185
Aplodactylids are temperate marine nearshore fish of New Zealand, southern Australia, several south-west Pacific islands, and western South America. The molecular phylogeny of the five aplodactylid species was reconstructed from mitochondrial DNA sequences. The observed relationships and levels of genetic variation supports the most recent review of the Aplodactylidae in which the monotypic Crinodus is synonymized with Aplodactylus, the only genus presently recognized. Phylogenetic relationships indicate that the Aplodactylidae originated in the approximate region of Australia and New Zealand, with the majority of radiation occurring prior to this family achieving representation in South America. The disjunct trans-Pacific distribution of this family was the result of chance dispersal rather than vicariance accompanying Gondwana fragmentation. Such dispersal was most likely undertaken during the larval phase, mediated by the West Wind Drift current. 相似文献
1