有限弹塑性变形的几何模型

以连续介质力学内变量理论为基础，建立了一个以材料内部微结构变量为底流形，材料外部变形状为对应纤维的材料状态纤维丛模型，使材料的力学特性与模型的几何性质自然对应起来。在模型上讨论和分析了有限弹塑性变形中变形梯度的Lee和Clifton的分解和联系，并证明了塑性变形为沿内变量演化在纤维丛的水平空间的运动。由此获得了塑性变形随内变量演化的变化方程和塑性梯度与内变演化的协调关系。

Molecular and morphological data suggest that Spinibarbus caldwelli (Nichols) (Teleostei : Cyprinidae) is a valid species

The taxonomic problem of the cyprinid species of genus Spinibarbus, occurring in southern China and northern Vietnam, was resolved on the basis of molecular and morphological analyses. Spinibarbus caldwelli and Spinibarbus hollandi have a smooth posterior edge of the last unbranched dorsal fin ray among species in the genus. Spinibarbus caldwelli is currently regarded as a junior synonym of S. hollandi because of ambiguities in diagnostic characters. In this article, 11 mtDNA cytochrome b sequences of Spinibarbus specimens were analyzed together with Barbodes gonionotus and Puntius conchonius as outgroups. Our results showed that specimens identified as S. hollandi from Taiwan were different from those from the Asian mainland at a high level of genetic divergence (0.097-0.112), which is higher than that between the two valid species, S. sinensis and S. yunnanensis ( 0.089), and suggested that Taiwan specimens should be considered as a different species from the Asian mainland one. In a molecular phylogenetic analysis, the sister-group relationship between Taiwan specimens and the Asian mainland specimens was supported strongly by a high confidence level ( 100% in bootstrap value). Further analysis of morphological characters showed that overlap of diagnostic characters is much weaker than previously suggested. Taiwan specimens had 8 branched rays in the dorsal fin, whereas those from the mainland had almost 9-10. The molecular and morphological differences suggest S. caldwelli to be valid. The molecular divergence shows the genetic speciation of S. hollandi and S. caldwelli might have occurred 5.6-4.9 million years ago; the former could be a relict species in Taiwan, and the latter dispersed in the Asian mainland.

粗疣类钱袋苔[Apomarsupellaverrucosa(Nichols.)Vana]及其新异名

对产自中国云南缺萼苔科(Gymnomitriaceae)粗疣类钱袋苔(Apomarsupella verrucosa(Nichols.)Vana)和产自尼泊尔(Gymnomitrion papillosumKitag.&S.Hatt.)的模式标本进行了对比研究,发现Gymnomitrion papillosum���粗疣类钱袋苔特征相一致,将其处理为粗疣类钱袋苔的异名。