The Yarlung Zangbo River Basin is an important populated area in Tibet, and its plant community structure and diversity pattern have attracted the attention of many scholars. In this paper, the distribution pattern of...The Yarlung Zangbo River Basin is an important populated area in Tibet, and its plant community structure and diversity pattern have attracted the attention of many scholars. In this paper, the distribution pattern of plant diversity and the environmental factors impacting it in the middle and upper reaches of the Yarlung Zangbo River are revealed and discussed through sample surveys and climate and habitat data. The results show that the plant communities in the study area can be divided into seven types according to the dominant species: Artemisia minor + Stipa purpurea, Artemisia wellbyi + Festuca ovina, Potentilla fruticosa + Orinus thoroldii, Trikeraia hookeri + Artemisia frigida, Kobresia pygmaea, Sophora moorcroftiana + Artemisia hedinii, and Sophora moorcroftiana + Pennisetum centrasiaticum. Plant diversity decreases with decreasing longitude, increasing latitude, and increasing altitude;and the diversity distribution pattern in the study area has distinct zonal characteristics. Water and heat are the main factors which affect the distribution of vegetation types. The explanation rates of water and heat for the plant diversity distribution pattern were 19.3% and 5.7%, respectively, while the spatial variation explained by these two factors together was 60.8%. Therefore, the coupling effect is obvious.展开更多
Ab-initio molecular dynamics simulation was performed to investigate the local atomic structure of Co55Ta^0B35 alloys. Pair distribution function, coordination number, HA index and Voronoi polyhedra were used to descr...Ab-initio molecular dynamics simulation was performed to investigate the local atomic structure of Co55Ta^0B35 alloys. Pair distribution function, coordination number, HA index and Voronoi polyhedra were used to describe the detailed local structure of this alloy. It was revealed Co7TalB2, Co6TalB2 and CosTa2B4 among the dominant （0 3 6 0）, （0 4 4 0）, （0 1 10 2） and （0 3 6 4） polyhedra were the basic local structure units in CossTal0B3s amorphous alloy. Furthermore, most of the dominant poly- hedra tended to have Ta atoms involved and these polyhedra may have a critical role during glass formation.展开更多
基金The National Key Research and Development Program of China (2016YFC0502006)。
文摘The Yarlung Zangbo River Basin is an important populated area in Tibet, and its plant community structure and diversity pattern have attracted the attention of many scholars. In this paper, the distribution pattern of plant diversity and the environmental factors impacting it in the middle and upper reaches of the Yarlung Zangbo River are revealed and discussed through sample surveys and climate and habitat data. The results show that the plant communities in the study area can be divided into seven types according to the dominant species: Artemisia minor + Stipa purpurea, Artemisia wellbyi + Festuca ovina, Potentilla fruticosa + Orinus thoroldii, Trikeraia hookeri + Artemisia frigida, Kobresia pygmaea, Sophora moorcroftiana + Artemisia hedinii, and Sophora moorcroftiana + Pennisetum centrasiaticum. Plant diversity decreases with decreasing longitude, increasing latitude, and increasing altitude;and the diversity distribution pattern in the study area has distinct zonal characteristics. Water and heat are the main factors which affect the distribution of vegetation types. The explanation rates of water and heat for the plant diversity distribution pattern were 19.3% and 5.7%, respectively, while the spatial variation explained by these two factors together was 60.8%. Therefore, the coupling effect is obvious.
基金supported by the National Natural Science Foundation of China (Grant No. 51101004)the Fundamental Research Funds for the Central Universities
文摘Ab-initio molecular dynamics simulation was performed to investigate the local atomic structure of Co55Ta^0B35 alloys. Pair distribution function, coordination number, HA index and Voronoi polyhedra were used to describe the detailed local structure of this alloy. It was revealed Co7TalB2, Co6TalB2 and CosTa2B4 among the dominant （0 3 6 0）, （0 4 4 0）, （0 1 10 2） and （0 3 6 4） polyhedra were the basic local structure units in CossTal0B3s amorphous alloy. Furthermore, most of the dominant poly- hedra tended to have Ta atoms involved and these polyhedra may have a critical role during glass formation.
