Electronic transport properties of coupled quantum dots on carbon nanotubes.

We investigate the electronic transport properties of coupled quantum dots, controlled by local gates on carbon nanotubes. The inter-dot coupling can be tuned from weak to strong by changing gate voltages, and oscillates in short and long period with the distance between two gates. We introduce a one-dimensional scattering model to describe the mechanism of the electron transport through the carbon nanotube quantum dots.

Nucleotide capacitance calculation for DNA sequencing.

Using a first-principles linear response theory, the capacitance of the DNA nucleotides, adenine, cytosine, guanine, and thymine, are calculated. The difference in the capacitance between the nucleotides is studied with respect to conformational distortion. The result suggests that although an alternate current capacitance measurement of a single-stranded DNA chain threaded through a nanogap electrode may not be sufficient to be used as a standalone method for rapid DNA sequencing, the capacitance of the nucleotides should be taken into consideration in any GHz-frequency electric measurements and may also serve as an additional criterion for identifying the DNA sequence.

Standing Friedel waves: a quantum probe of electronic states in nanoscale devices.

We report a theoretical study of the dynamic response of electrons in a metallic nanowire or a two-dimensional electron gas under a capacitively coupled "spot gate" driven by an ac voltage. A dynamic standing Friedel wave (SFW) is formed near the spot gate and near edges and boundaries, analogous to the static Friedel oscillations near defects. The SFW wavelength is controlled by the ac voltage frequency and the device's Fermi velocity, whereby the latter can be measured.

Random-walk statistics in moment-based O(N) tight binding and applications in carbon nanotubes.

A computational framework for a moment-based O(N) tight-binding atomistic method is presented, analyzed, and applied to the problem of electronic properties of deformed carbon nanotubes, where N is the number of atoms in the system. The moment-based approach is based on the maximum entropy and kernel polynomial methods for constructing the electronic density of states from local statistical information about the environment around individual atoms. Random-walk statistics are formally presented as the basis for several methods to collect the moments of the density of states in a computationally efficient manner.

[Application of non-invasive hemodynamic monitoring on high-risk surgical patients in the early stages after emergency admission].

Objective: Pulmonary artery (PA) catheterization monitoring (Swan-Ganz) is usually not available to critically high-risk surgical patients before admission to ICU, where action to correct values derived from such monitoring may be too late. To explored the effect of non-invasive monitoring systems that allow hemodynamic monitoring during the early stages after trauma.

Methods: The early temporal hemodynamic patterns after high-risk trauma with non-invasive monitoring systems were evaluated, and compared these to invasive PA monitoring.

Metal-to-semiconductor transition in squashed armchair carbon nanotubes.

We investigate electronic transport properties of the squashed armchair carbon nanotubes, using tight-binding molecular dynamics and the Green's function method. We demonstrate a metal-to-semiconductor transition while squashing the nanotubes and a general mechanism for such a transition. It is the distinction of the two sublattices in the nanotube that opens an energy gap near the Fermi energy.