Asian origin for Polystichum （Dryopteridaceae） based on rbcL sequences

Chloroplast rbcL sequences of 60 species of Polystichum sensu lato (s.l.), including 23 new sequences from southwest China, were used to assess the phylogenetic relationships within the genus. On the basis of estimated evolution rate of rbcL gene and the genetic distance data that passed relative-rate tests, we further estimated the divergence times between some clades of the genus. The phylogenetic relationships were inferred using the neighbor-joining and maximum-parsimony methods, both methods producing trees with completely congruent topology. These trees reveal that all species of Polystichum s.l. in this study (including Cyrtomium and Cyrtomidictyum) form a monophyletic group. The basal split in Polystichum s.l. separates a clade with all Asian members from a clade containing other species from all over the world. The phylogenetic and divergence time estimation results lead us to suggest that Polystichum s.l. originated in Asia in the late Late Cretacous (≈76 Ma) and migrated into other places in the world in early Eocene(≈46 Ma).     

菲涅耳圆孔衍射的轴上光强分布

本文从惠更斯－菲涅耳原理出发，在球面波入射的情况下，导出了菲涅耳圆孔衍射的轴上光强分布的解析表达式，并对轴上光强分布进行了定量的分析讨论。     

热释电红外线自动开关的设计

介绍了热释电红外线自动开关的设计步骤及各部分的作用，并给出了实用的电路。该开关接上执行机构就可以直接构成实用系统。     

透明介质表面反射光和折射光的偏振态

本文从透明的各向同性介质表面反射光、折射光的位相变化出发,详细地分析了入射光分别为自然光、线偏振光、圆偏振光时,反射光和折射光所对应的偏振状态。     

大耳猬冬眠前日活动节律的初步研究

大耳猬冬眠前日活动节律的初步研究杨贵生，邢莲莲（内蒙古大学生物学系，０１００２１，呼和浩特关键词大耳猬，活动节律，内蒙古）ＯｎｔｈｅＤａｉｌｙＡｃｔｉｖｉｔｙＲｈｙｔｈｍｂｅｆｏｒｅＨｉｂｅｒｎａｔｉｏｎｏｆＬｏｎｇ－ＥａｒｅｄＨｅｄｇｅｈｏｇＹａｎ...     

Inclusion of the Eastern Asia endemic genus Sorolepidium in Polystichum （Dryopteridaceae）： Evidence from the chloroplast rbcL gene and morphological characteristics

The taxonomic status of the Eastern Asia endemic Sorolepidium is controversial. Some authors accept it as member of the large diverse genus Polystichum, whereas others suggest that it is an independent genus separated from the later by the exindusiate sorus and the absence of aristate teeth at the pinnae margins. Here we infer phylogenetic relationship of Sorolepidium using DNA sequences of the chloro-plast rbcL gene. Phylogenies were inferred using maximum-parsimony, maximum-likelihood, and Bayesian inference methods. Molecular data establish that Sorolepidium is deeply nested within the large genus Polystichum and has a close relationship with P. duthiei and P. lachenense in the model-based analyses. The Kimura 2-parameter distances of the rbcL sequences between S. glaciale and P. duthiei and P. lachenense were 0.1 and 0.2%, respectively. Furthermore, S. glaciale differed from P. duthiei by a single nucleotide in their rbcL sequences. Close relationships between S. glaciale and P. duthiei and P. lachenense are also supported by the shared spore ornamentation with echinate fenes-trate folds.     

电磁波在导体中传播的几个问题的探讨

由边值关系出发,讨论了折射波的传播方向、波长、能量和穿透深度,得出电磁波在导体面上折射时,波长会变短;推导了以任意入射角入射的菲涅耳公式和反射系数,根据该组公式分析了以自然光入射的反射波与折射波的偏振特性。