4,289 research outputs found

    Single molecule DNA sequencing via transverse electronic transport using a graphene nanopore: A tight-binding approach

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    We report a tight-binding model study of two-terminal graphene nanopore based device, for sequential determination of DNA bases. Using Greens function approach we calculate conductance spectra, I-V response and also the changes in local density of states (LDOS) profile as four different nucleobases inserted one by one into the pore embedded in the zigzag graphene nanoribbon (ZGNR). We find distinct features in LDOS profile for different nucleotides and the same is also present in conductance and I-V response. We propose the actual working principle of the device, by setting the bias across the pore to a fixed voltage (this voltage gives maximum discrimination between characteristic current of the four nucleotides) and translocating the ss-DNA through the nanopore using a transverse electric field while recording the characteristic current of the nucleotides. Not only the typical current output is much larger than previous results, but the seaparation between them for different bases are also definite. Our investigation provides high accuracy and significant amount of distinction between different nucleotides.Comment: 6 pages, 5 figure

    Image-Dependent Spatial Shape-Error Concealment

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    Existing spatial shape-error concealment techniques are broadly based upon either parametric curves that exploit geometric information concerning a shape's contour or object shape statistics using a combination of Markov random fields and maximum a posteriori estimation. Both categories are to some extent, able to mask errors caused by information loss, provided the shape is considered independently of the image/video. They palpably however, do not afford the best solution in applications where shape is used as metadata to describe image and video content. This paper presents a novel image-dependent spatial shape-error concealment (ISEC) algorithm that uses both image and shape information by employing the established rubber-band contour detecting function, with the novel enhancement of automatically determining the optimal width of the band to achieve superior error concealment. Experimental results corroborate both qualitatively and numerically, the enhanced performance of the new ISEC strategy compared with established techniques

    Ground state phase diagram and magnetoconductance of a one-dimensional Hubbard superlattice at half-filling

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    We have studied a one dimensional Hubbard superlattice with different Coulomb correlations at alternating sites for a half-filled band. Mean field calculations based on the Hartree-Fock approximation together with a real space renormalization group technique were used to study the ground state of the system. The phase diagrams obtained in these approaches agree with each other from the weak to the intermediate coupling regime. The mean field results show very quick convergence with system size. The renormalization group results indicate a spatial modulation of local moments that was identified in some previous work. Also we have studied the magnetoconductance of such superlattices which reveals several interesting points.Comment: 10 pages, 13 figures. to be published in Phys. Rev. B, vol. 75, Issue 23 (tentative