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Articles 1 - 11 of 11
Full-Text Articles in Physical Sciences and Mathematics
Modelling Carbon Nanostructures For Filtering And Adsorbing Polycyclic Aromatic Hydrocarbons, Thien Tran-Duc, Ngamta Thamwattana
Modelling Carbon Nanostructures For Filtering And Adsorbing Polycyclic Aromatic Hydrocarbons, Thien Tran-Duc, Ngamta Thamwattana
Faculty of Informatics - Papers (Archive)
The discovery of carbon nanostructures, such as graphene and carbon nanotubes, has led to the creation of many novel nano-devices. In this paper, we consider an environmental application of carbon nanostructures for filtering and adsorbing polycyclic aromatic hydrocarbons (PAHs) which are environmental pollutants. We mathematically investigate the adsorption of PAHs onto a graphene sheet and determine the underlying mechanisms of suction of PAHs into a carbon nanotube. We adopt a continuum approach together with the semi-empirical Lennard-Jones potential to determine van der Waals interaction forces and energies. Results obtained here for certain PAHs are well in agreement with existing experimental …
Electronic Properties Of Carbon Nanotubes With Distinct Bond Lengths, J E. Bunder, James M. Hill
Electronic Properties Of Carbon Nanotubes With Distinct Bond Lengths, J E. Bunder, James M. Hill
Faculty of Informatics - Papers (Archive)
In band structure calculations commonly used to derive the electronic properties of carbon nanotubes it is generally assumed that all bond lengths are equal. However, hexagonal carbon lattices are often irregular and may contain as many as three distinct bond lengths. A regular $(n,m)$ carbon nanotube will be metallic if p=(n-m)/3 for integer p. Here we analytically derive the generalized condition for metallic irregular carbon nanotubes. This condition is particularly relevant to small radius nanotubes and nanotubes experiencing small applied strains.
Diffusive Growth Of Fullerenes And Carbon Nanotubes, J E. Bunder, James M. Hill
Diffusive Growth Of Fullerenes And Carbon Nanotubes, J E. Bunder, James M. Hill
Faculty of Informatics - Papers (Archive)
The video of a growing fullerene within a carbon nanotube, initiated by a tungsten catalyst, provides a dramatic realization of a complex nanoscale process. While there may be many detailed models which can account for this growth, we propose one of the simplest possible models which is consistent with the major observed features of the growth process. In particular, we assume that the fullerene is immersed in a carbon vapor environment, and that the growth occurs as a consequence of the diffusion of the carbon vapor into the fullerene. Moreover, we assume that the classical diffusion equation applies in the …
Zigzag Carbon Nanotubes With Generic Electron-Electron Interactions, James M. Hill, J. E. Bunder
Zigzag Carbon Nanotubes With Generic Electron-Electron Interactions, James M. Hill, J. E. Bunder
Faculty of Informatics - Papers (Archive)
A Hamiltonian is derived for a zigzag carbon nanotube with an arbitrary number of weak electron-electron charge and spin interactions, which become significant in ultraclean systems. The renormalization group and bosonization are used to determine the ground-state phase diagram. Our phase diagram contains some exotic phases which have not previously been predicted in carbon nanotubes with physically possible interaction profiles. Phases of the undoped case include Mott insulators and a variety of density wave states. In the doped case a Tomanaga-Luttinger liquid is possible.
Phase Diagrams Of The Metallic Zigzag Carbon Nanotube, J E. Bunder, Hsiu-Hau Lin
Phase Diagrams Of The Metallic Zigzag Carbon Nanotube, J E. Bunder, Hsiu-Hau Lin
Faculty of Informatics - Papers (Archive)
We investigate a metallic zigzag carbon nanotube by means of a Hubbard model, which includes both on-site and nearest-neighbor interactions. Assuming weak interactions, a renormalization group analysis of the equivalent two-leg ladder followed by bosonization and refermionization results in a Gross-Neveu model with an enlarged symmetry relative to the original Hamiltonian. For the undoped case the symmetry of the Gross-Neveu model is SO_8_, but for the doped case the particle-hole symmetry is broken and the symmetry reduces to SO_6_. Four ground-state phases are found in the undoped carbon nanotube with repulsive interactions, a d-wave Mott insulator, an s-wave Mott insulator, …
Mechanics Of Fullerene-Carbon Nanotube Bundle Oscillators, James M. Hill, Ngamta Thamwattana, Duangkamon Baowan, Barry J. Cox
Mechanics Of Fullerene-Carbon Nanotube Bundle Oscillators, James M. Hill, Ngamta Thamwattana, Duangkamon Baowan, Barry J. Cox
Faculty of Informatics - Papers (Archive)
Carbon nanostructures, such as nanotubes and fullerenes, are of considerableinterest to a wide range of research communities. Owing to their unique properties, a numberof applications involving these structures have been proposed, one of which is the so-callednano-scaled oscillators, for which the resultant oscillatory frequencies are in the gigahertzrange. The phenomena of the gigahertz oscillations have also led to the possible creation offuture devices, such as ultra-fast optical filters and ultra-sensitive nano-antennae. In thispaper we present recent developments in this area and review the authors recent work,where we investigate the mechanics of a new type of gigahertz oscillator comprising afullerene C60 …
Dynamical Symmetry Enlargement In Metallic Zigzag Carbon Nanotubes, J E. Bunder, Hsiu-Hau Lin
Dynamical Symmetry Enlargement In Metallic Zigzag Carbon Nanotubes, J E. Bunder, Hsiu-Hau Lin
Faculty of Informatics - Papers (Archive)
No abstract provided.
Oscillating Carbon Nanotori Along Carbon Nanotubes, Tamsyn A. Hilder, James M. Hill
Oscillating Carbon Nanotori Along Carbon Nanotubes, Tamsyn A. Hilder, James M. Hill
Faculty of Informatics - Papers (Archive)
The discovery of carbon nanostructures, such as nanotubes and C60 fullerenes, has given rise to a number of potential nanoscale devices. One such device is the gigahertz oscillator, comprising an inner shell sliding inside an outer shell of a multiwalled carbon nanotube, and which, at least theoretically, generates oscillatory frequencies in the gigahertz range. Following the concept of these gigahertz oscillators and the recent discovery of “fullerene crop circles,” here we propose the notion of a nanotorus-nanotube oscillator comprising a carbon nanotorus which is sucked by the van der Waals force onto the carbon nanotube, and subsequently oscillates along the …
Continuum Modelling For Carbon And Boron Nitride Nanostructures, James M. Hill, Ngamta Thamwattana
Continuum Modelling For Carbon And Boron Nitride Nanostructures, James M. Hill, Ngamta Thamwattana
Faculty of Informatics - Papers (Archive)
Continmuum based models are presented here for certain boron nitride and carbon nanostructures.
Force Distribution For Double-Walled Carbon Nanotubes, Duangkamon Baowan, James M. Hill
Force Distribution For Double-Walled Carbon Nanotubes, Duangkamon Baowan, James M. Hill
Faculty of Informatics - Papers (Archive)
Advances in technology have led to the creation of many nano-scale devices and carbon nanotubes are representative materials to construct these devices. Double-walled carbon nanotubes with the inner tube oscillating can be used as gigahertz oscillators and form the basis of possible nano-electronic devices. Such gigahertz oscillating devices made from carbon nanotubes might be instrumental in the micro-computer industry, which is predominantly based on electron transport phenomena. There are many experiments and molecular dynamics simulations which show that a wave is generated on the outer cylinder by the oscillation of the carbon nanotubes and that the frequency of this wave …
Mathematical Modelling For A C60 Carbon Nanotube Oscillator, Barry J. Cox, Ngamta Thamwattana, James M. Hill
Mathematical Modelling For A C60 Carbon Nanotube Oscillator, Barry J. Cox, Ngamta Thamwattana, James M. Hill
Faculty of Informatics - Papers (Archive)
The discovery of fullerenes C60 and carbon nanotubes has created an enormous impact on nanotechnology. Because of their unique mechanical and electronic properties, such as low weight, high strength, flexibility and thermal stability, fullerenes C60 and carbon nanotubes are of considerable interest to researchers from many scientific areas. One problem that has attracted much attention is the creation of gigahertz oscillators. While there are difficulties for micromechanical oscillators, or resonators, to reach a frequency in the gigahertz range, it is possible for nanomechanical systems to achieve this. A number of studies have found that the sliding of the …