73,151 research outputs found

    Transmission of doughnut light through a bull's eye structure

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    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

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    Abstract—Cloud 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

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    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