74,901 research outputs found
Transmission of doughnut light through a bull's eye structure
We experimentally investigate the extraordinary optical transmission of
doughnut light through a bull's eye structure. Since the intensity is vanished
in the center of the beam, almost all the energy reaches the circular
corrugations (not on the hole), excite surface plasmons which propagate through
the hole and reradiate photons. The transmitted energy is about 57 times of the
input energy on the hole area. It is also interesting that the transmitted
light has a similar spatial shape with the input light although the diameter of
the hole is much smaller than the wavelength of light.Comment: 3 pages,4 figure
Investigation into Mobile Learning Framework in Cloud Computing Platform
AbstractâCloud computing infrastructure is increasingly
used for distributed applications. Mobile learning
applications deployed in the cloud are a new research
direction. The applications require specific development
approaches for effective and reliable communication. This
paper proposes an interdisciplinary approach for design and
development of mobile applications in the cloud. The
approach includes front service toolkit and backend service
toolkit. The front service toolkit packages data and sends it
to a backend deployed in a cloud computing platform. The
backend service toolkit manages rules and workflow, and
then transmits required results to the front service toolkit.
To further show feasibility of the approach, the paper
introduces a case study and shows its performance
Band Gap of Strained Graphene Nanoribbons
The band structures of strained graphene nanoribbons (GNRs) are examined by a
tight binding Hamiltonian that is directly related to the type and strength of
strains. Compared to the two-dimensional graphene whose band gap remains close
to zero even if a large strain is applied, the band gap of graphene nanoribbon
(GNR) is sensitive to both uniaxial and shears strains. The effect of strain on
the electronic structure of a GNR strongly depends on its edge shape and
structural indices. For an armchair GNR, uniaxial weak strain changes the band
gap in a linear fashion, and for a large strain, it results in periodic
oscillation of the band gap. On the other hand, shear strain always tend to
reduce the band gap. For a zigzag GNR, the effect of strain is to change the
spin polarization at the edges of GNR, thereby modulate the band gap. A simple
analytical model is proposed to interpret the band gap responds to strain in
armchair GNR, which agrees with the numerical results.Comment: 30 pages,10 figure
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