中文摘要：

系统地计算了各种手性碳纳米管最低导带的电子速度和有效质量的变化规律,在此基础上推断手性碳纳米管低偏压下的输运特征,计算表明：在低偏压电子输运时,同一系列（手性角相同）的各种手性金属碳纳米管的输运性质相同,与管径无关,但不同系列的手性金属碳纳米管的输运性质有明显区别;而同一系列的各种手性半导体型碳纳米管的输运性质有一定差异,但不同系列的手性半导体型碳纳米管的输运性质有着显著差异.这一结果说明：碳纳米管在低偏压下的输运特征与系列有着密切的关系,手性角是决定各种碳纳米管在低偏压下具有不同输运性质的最关键的几何参量.

英文摘要：

In this paper, changing patterns of electronic velocity and effective mass of the lowest conduction band for various carbon nanotubes are calculated systematically. Based on these calculation results,low-bias transport properties of single- walled carbon nanotubes （SWCNTs） and deduced thoroughly. It is found that under a low bias,chiral metallic SWCNTs belonging to the same series （ i. e,having the same chiral angles） have the entirely identical transport properties and are independent of diameter of the SWCNT. But those that belong to different series have obviously distinguishable transport properties. While for chiral semi-conducting SWCNTs belonging to the same series, they have some different transport properties. But those that belong to different series have greatly different transport properties. Our findings suggest that low-bias transport properties of SWCNTs are intimately related to the series and the chiral angle is the most important geometry parameter for the determination of different low-bias transport properties of various SWCNTs.