Synthesis and Modification of Boron Nitride nanotubes using ion implantation.

In this work, Chemical Vapour Deposition (CVD) has been used to synthesize boron nitride (BN) nanostructures, particularly nanotubes, and selectively introduce defects into the lattice of the synthesized BN nanostructures through ion implantation. Scanning electron microscopy (SEM) images show clear evidence of BN nanostructures and BN nanotubes (BNNTs), with the latter appearing as long, thin structures with diameters ranging from ⁓30-80 nm. Raman analysis show an E mode of vibration assigned to hexagonal BN (h-BN) at 1366 cm after ion implantation, with increased intensity.

Interaction of diamond (111)-(1 × 1) and (2 × 1) surfaces with OH: a first principles study.

The properties of hydroxyl groups on C(111)-(1 × 1) and reconstructed (2 × 1) surfaces at different sites and for various coverages are investigated using density functional theory. Out of the adsorption sites considered, i.e.

Oxygen adsorption on the (1×1) and (2×1) reconstructed C(111) surfaces: a density functional theory study.

The structural and electronic properties, stability, optimum coverage and workfunction of oxygen atoms at different sites on the (1×1) unreconstructed and the (2×1) reconstructed C(111) surfaces have been investigated using density functional theory. Oxygen atoms prefer on-top sites on the C(111)-(1×1) surface, with an optimum coverage of 1/3 monolayers (ML), while on the (2×1) reconstructed surface, bridge sites are preferred with a coverage of 1/2 ML. With increasing oxygen coverage greater than 1/3 ML on the (1×1) surface, a repulsive interaction develops between the oxygen atoms, while for the (2×1) surface such a repulsive interaction occurs for coverages greater than 0.

Tell-tale teeth: abrasion from the traditional clay pipe.

The long story of the once very widespread clay pipe has a minor but significant odontological aspect: some clay-pipe smokers may be characterized by a distinctive abrasion pattern of the teeth. The marks in question are of special interest to the archaeologist; attention is here directed particularly to the Scandinavian experience.