Electron transport in semiconducting carbon nanotubes with hetero-metallic contacts

We present an atomistic self-consistent study of the electronic and transport properties of semiconducting carbon nanotube in contact with metal electrodes of different work functions, which shows simultaneous electron and hole doping inside the nanotube junction through contact-induced charge transfer. We find that the band lineup in the nanotube bulk region is determined by the effective work function difference between the nanotube channel and source/drain electrodes, while electron transmission through the SWNT junction is affected by the local band structure modulation at the two metal-nanotube interfaces, leading to an effective decoupling of interface and bulk effects in electron transport through nanotube junction devices.Comment: Higher quality figures available at http://www.albany.edu/~yx15212

An Arctic-Tibetan Connection on Subseasonal to Seasonal Time Scale

Recent research indicates the great potentials of springtime land surface temperature (LST) as a new source of predictability to improve the subseasonal to seasonal climate prediction. In this study, we explore the initial cause of the springtime large-scale LST in Tibetan Plateau (TP) and disentangle its close connection with the February wave activities from the Arctic region. Our Maximum Covariance Analysis show that the spring LST in TP is significantly coupled with the regional snow cover in the preceding months. The latter is further strongly coupled with the February atmospheric circulation and wave activities in mid-to-high latitudes. When the atmospheric circulation is in a combined pattern of Arctic Oscillation and West Pacific teleconnection pattern, wave trains from the Arctic can propagate and reach the TP through northern and southern pathways. This brings dynamical and moisture conditions for the TP snowfall and builds a bridge for Arctic-Tibetan connection

Scaling analysis of Schottky barriers at metal-embedded semiconducting carbon nanotube interfaces

We present an atomistic self-consistent tight-binding study of the electronic and transport properties of metal-semiconducting carbon nanotube interfaces as a function of the nanotube channel length when the end of the nanotube wire is buried inside the electrodes. We show that the lineup of the nanotube band structure relative to the metal Fermi-level depends strongly on the metal work function but weakly on the details of the interface. We analyze the length-dependent transport characteristics, which predicts a transition from tunneling to thermally-activated transport with increasing nanotube channel length.Comment: To appear in Phys.Rev.B Rapid Communications. Color figures available in PRB online versio

Automatic collision avoidance of ships

One of the key elements in automatic simulation of ship manoeuvring in confined waterways is route finding and collision avoidance. This paper presents a new practical method of automatic trajectory planning and collision avoidance based on an artificial potential field and speed vector. Collision prevention regulations and international navigational rules have been incorporated into the algorithm. The algorithm is fairly straightforward and simple to implement, but has been shown to be effective in finding safe paths for all ships concerned in complex situations. The method has been applied to some typical test cases and the results are very encouraging