1,542 research outputs found

    Analytical Modeling of Channel Noise for Gate Material Engineered Surrounded/Cylindrical Gate (SGT/CGT) MOSFET

    Get PDF
    In this paper, an analytical modeling is presentated to describe the channel noise in GME SGT/CGT MOSFET, based on explicit functions of MOSFETs geometry and biasing conditions for all channel length down to deep submicron and is verified with the experimental data. Results shows the impact of various parameters such as gate bias, drain bias, channel length ,device diameter and gate material work function difference on drain current noise spectral density of the device reflecting its applicability for circuit design applications

    Pinned Balseiro-Falicov Model of Tunneling and Photoemission in the Cuprates

    Full text link
    The smooth evolution of the tunneling gap of Bi_2Sr_2CaCu_2O_8 with doping from a pseudogap state in the underdoped cuprates to a superconducting state at optimal and overdoping, has been interpreted as evidence that the pseudogap must be due to precursor pairing. We suggest an alternative explanation, that the smoothness reflects a hidden SO(N) symmetry near the (pi,0) points of the Brillouin zone (with N = 3, 4, 5, or 6). Because of this symmetry, the pseudogap could actually be due to any of a number of nesting instabilities, including charge or spin density waves or more exotic phases. We present a detailed analysis of this competition for one particular model: the pinned Balseiro-Falicov model of competing charge density wave and (s-wave) superconductivity. We show that most of the anomalous features of both tunneling and photoemission follow naturally from the model, including the smooth crossover, the general shape of the pseudogap phase diagram, the shrinking Fermi surface of the pseudogap phase, and the asymmetry of the tunneling gap away from optimal doping. Below T_c, the sharp peak at Delta_1 and the dip seen in the tunneling and photoemission near 2Delta_1 cannot be described in detail by this model, but we suggest a simple generalization to account for inhomogeneity, which does provide an adequate description. We show that it should be possible, with a combination of photoemission and tunneling, to demonstrate the extent of pinning of the Fermi level to the Van Hove singularity. A preliminary analysis of the data suggests pinning in the underdoped, but not in the overdoped regime.Comment: 18 pages LaTeX, 26 ps. figure

    On the fourth-order accurate compact ADI scheme for solving the unsteady Nonlinear Coupled Burgers' Equations

    Full text link
    The two-dimensional unsteady coupled Burgers' equations with moderate to severe gradients, are solved numerically using higher-order accurate finite difference schemes; namely the fourth-order accurate compact ADI scheme, and the fourth-order accurate Du Fort Frankel scheme. The question of numerical stability and convergence are presented. Comparisons are made between the present schemes in terms of accuracy and computational efficiency for solving problems with severe internal and boundary gradients. The present study shows that the fourth-order compact ADI scheme is stable and efficient

    Advances in multispectral and hyperspectral imaging for archaeology and art conservation

    Get PDF
    Multispectral imaging has been applied to the field of art conservation and art history since the early 1990s. It is attractive as a noninvasive imaging technique because it is fast and hence capable of imaging large areas of an object giving both spatial and spectral information. This paper gives an overview of the different instrumental designs, image processing techniques and various applications of multispectral and hyperspectral imaging to art conservation, art history and archaeology. Recent advances in the development of remote and versatile multispectral and hyperspectral imaging as well as techniques in pigment identification will be presented. Future prospects including combination of spectral imaging with other noninvasive imaging and analytical techniques will be discussed

    Tests for a Strong Electroweak Sector at Future e^+e^- High Energy Colliders

    Get PDF
    The study of the scattering at high energy of the gauge bosons W and Z, in particular longitudinally polarized W and Z, can clarify the mechanism of spontaneous symmetry breaking in the Standard Model of the electroweak interactions. Different models of strong electroweak sector, based on the effective lagrangian approach are briefly reviewed. They include models with no resonance, with scalar resonance, additional vector and axial-vector resonances. The effective Lagrangians are derived from the chiral symmetry of the symmetry breaking sector. Limits on these models from existing measurements, mainly LEP and Tevatron, are considered. We study also direct and indirect effects of the new interactions at high energy future e^+e^- linear colliders, through WW scattering and the direct production of these new vector gauge bosons.Comment: 74 pages, 19 figures and 4 tables included, Latex, uses epsf, to appear in La Rivista del Nuovo Cimento, some minor change

    Effective Lagrangian Approach to the Theory of Eta Photoproduction in the N(1535)N^{*}(1535) Region

    Full text link
    We investigate eta photoproduction in the N(1535)N^{*}(1535) resonance region within the effective Lagrangian approach (ELA), wherein leading contributions to the amplitude at the tree level are taken into account. These include the nucleon Born terms and the leading tt-channel vector meson exchanges as the non-resonant pieces. In addition, we consider five resonance contributions in the ss- and uu- channel; besides the dominant N(1535)N^{*}(1535), these are: N(1440),N(1520),N(1650)N^{*}(1440),N^{*}(1520),N^{*}(1650) and N(1710)N^{*}(1710). The amplitudes for the π\pi^\circ and the η\eta photoproduction near threshold have significant differences, even as they share common contributions, such as those of the nucleon Born terms. Among these differences, the contribution to the η\eta photoproduction of the ss-channel excitation of the N(1535)N^{*}(1535) is the most significant. We find the off-shell properties of the spin-3/2 resonances to be important in determining the background contributions. Fitting our effective amplitude to the available data base allows us to extract the quantity χΓηA1/2/ΓT\sqrt{\chi \Gamma_\eta} A_{1/2}/\Gamma_T, characteristic of the photoexcitation of the N(1535)N^{*}(1535) resonance and its decay into the η\eta-nucleon channel, of interest to precise tests of hadron models. At the photon point, we determine it to be (2.2±0.2)×101GeV1(2.2\pm 0.2)\times 10^{-1} GeV^{-1} from the old data base, and (2.2±0.1)×101GeV1(2.2\pm 0.1) \times 10^{-1} GeV^{-1} from a combination of old data base and new Bates data. We obtain the helicity amplitude for N(1535)γpN^{*}(1535)\rightarrow \gamma p to be A1/2=(97±7)×103GeV1/2A_{1/2}=(97\pm 7)\times 10^{-3} GeV^{-1/2} from the old data base, and A1/2=(97±6)×103GeV1/2A_{1/2}=(97\pm 6)\times 10^{-3} GeV^{-1/2} from the combination of the old data base and new Bates data, compared with the results of the analysis of pion photoproduction yielding 74±1174\pm 11, in the same units.Comment: 43 pages, RevTeX, 9 figures available upon request, to appear in Phys. Rev.

    Longitudinal double-spin asymmetry and cross section for inclusive neutral pion production at midrapidity in polarized proton collisions at sqrt(s) = 200 GeV

    Get PDF
    We report a measurement of the longitudinal double-spin asymmetry A_LL and the differential cross section for inclusive Pi0 production at midrapidity in polarized proton collisions at sqrt(s) = 200 GeV. The cross section was measured over a transverse momentum range of 1 < p_T < 17 GeV/c and found to be in good agreement with a next-to-leading order perturbative QCD calculation. The longitudinal double-spin asymmetry was measured in the range of 3.7 < p_T < 11 GeV/c and excludes a maximal positive gluon polarization in the proton. The mean transverse momentum fraction of Pi0's in their parent jets was found to be around 0.7 for electromagnetically triggered events.Comment: 6 pages, 3 figures, submitted to Phys. Rev. D (RC
    corecore