2,209 research outputs found

    Temporal changes of Fluvio-Morphological scenario and its impact on Settlement: A GIS based study for Mandia block, Barpeta District, Assam

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    The Mandia Block of Barpeta District Assam undergoes episodes of changing geomorphology due to change in Manas-Beki-Brahmaputra River System. Significant amount of Geographical area within the block is covered by this river system. Temporal change in River System leads to change in sandbars which are being used by thousands of people as their settlement and agriculture. Geospatial Technology is used to study temporal change within the Block between 1972 and 2013. Within 41 years significant change has been observed in fluvial scenario and settlement pattern in this area. The Beki river shows significant shift in its channel pattern and confluence; River Brahmaputra tend to widen towards north causing major erosion in 1972 Northern bank line. Nearly thirteen settlements got severely affected by this change. Present day directions of Remote Sensing are identification, mapping, inventory, monitoring and surveillance. Hence it is found to be an effective tool for attempting this problem of temporal behavior of the river system

    Analysis of the resistance in p-SiGe over a wide temperature range

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    The temperature dependence of a system exhibiting a `metal-insulator transition in two dimensions at zero magnetic field' (MIT) is studied up to 90K. Using a classical scattering model we are able to simulate the non-monotonic temperature dependence of the resistivity in the metallic high density regime. We show that the temperature dependence arises from a complex interplay of metallic and insulating contributions contained in the calculation of the scattering rate 1/\td(E,T), each dominating in a limited temperature range.Comment: 4 pages with 5 figure

    Understanding the bulk electronic structure of Ca1-xSrxVO3

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    We investigate the electronic structure of Ca1-xSrxVO3 using careful state-of-the-art experiments and calculations. Photoemission spectra using synchrotron radiation reveal a hitherto unnoticed polarization dependence of the photoemission matrix elements for the surface component leading to a substantial suppression of its intensity. Bulk spectra extracted with the help of experimentally determined electron escape depth and estimated suppression of surface contributions resolve outstanding puzzles concerning the electronic structure in Ca1-xSrxVO3.Comment: 4 pages including 3 figure

    Analytical Solution of Electron Spin Decoherence Through Hyperfine Interaction in a Quantum Dot

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    We analytically solve the {\it Non-Markovian} single electron spin dynamics due to hyperfine interaction with surrounding nuclei in a quantum dot. We use the equation-of-motion method assisted with a large field expansion, and find that virtual nuclear spin flip-flops mediated by the electron contribute significantly to a complete decoherence of transverse electron spin correlation function. Our results show that a 90% nuclear polarization can enhance the electron spin T2T_2 time by almost two orders of magnitude. In the long time limit, the electron spin correlation function has a non-exponential 1/t21/t^2 decay in the presence of both polarized and unpolarized nuclei.Comment: 4 pages, 3 figure

    Regge behaviour of distribution functions and evolution of gluon distribution function in Next-to-Leading order at low-x

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    Evolution of gluon distribution function from Dokshitzer-Gribov-Lipatov-Altarelli-Parisi (DGLAP) evolution equation in next-to-leading order (NLO) at low-x is presented assuming the Regge behaviour of quarks and gluons at this limit. We compare our results of gluon distribution function with MRST2004, GRV98LO and GRV98NLO parameterizations and show the compatibility of Regge behaviour of quark and gluon distribution functions with perturbative quantum chromodynamics (PQCD) at low-x.Comment: 12 pages, 4 figure

    Hall state quantization in a rotating frame

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    We derive electromagnetomotive force fields for charged particles moving in a rotating Hall sample, satisfying a twofold U(1) gauge invariance principle. It is then argued that the phase coherence property of quantization of the line integral of total collective particle momentum into multiples of Planck's quantum of action is solely responsible for quantization in the Hall state. As a consequence, the height of the Hall quantization steps should remain invariant in a rapidly rotating Hall probe. Quantum Hall particle conductivities do not depend on charge and mass of the electron, and are quantized in units of the inverse of Planck's action quantum.Comment: 6 pages, accepted for publication in Europhysics Letter
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