9,922 research outputs found
Self-assembled metallic nanoparticle template --- a new approach of surface nanostructuring at nanometer scale
In the present work, the formation of silver and copper nanostructures on
highly oriented pyrolytic graphite (HOPG) modified with self-assembled gold
nanoparticles (Au NPs) is demonstrated. Surface patterning with nanometer
resolution was achieved. Different methods such as field emission scanning
electron microscopy (FEGSEM), energy dispersive spectrometry (EDS) and X-ray
photoelectron spectroscopy (XPS) were used to illustrate a selective deposition
of silver and copper on Au NPs. The mechanism of silver and copper ions
reduction on Au NP with -dodecanethiol coating is discussed.Comment: 6 pages, 3 figure
Noncommutative Multi-Instantons on R^{2n} x S^2
Generalizing self-duality on R^2 x S^2 to higher dimensions, we consider the
Donaldson-Uhlenbeck-Yau equations on R^{2n} x S^2 and their noncommutative
deformation for the gauge group U(2). Imposing SO(3) invariance (up to gauge
transformations) reduces these equations to vortex-type equations for an
abelian gauge field and a complex scalar on R^{2n}_\theta. For a special
S^2-radius R depending on the noncommutativity \theta we find explicit
solutions in terms of shift operators. These vortex-like configurations on
R^{2n}_\theta determine SO(3)-invariant multi-instantons on R^{2n}_\theta x
S^2_R for R=R(\theta). The latter may be interpreted as sub-branes of
codimension 2n inside a coincident pair of noncommutative Dp-branes with an S^2
factor of suitable size.Comment: 1+8 pages, v2: reference added, version published in PL
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