3,025 research outputs found

    QCD on a transverse lattice

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    We present results from a transverse lattice study of low lying mesons. Special emphasis is put on the issue of Lorentz invariant energy-momentum dispersion relations for these mesons. The light-cone wave function for the π\pi obtained in this framework is very close to its asymptotic shape.Comment: 10 pages, sprocl.sty, invited talk given at 5th International Workshop on Particle Phyiscs Phenomenology, Chi-Pen, Taitung, Taiwan, 8-11 Nov 200

    Ageing in Medieval Jewish Culture, Elisha Russ-Fishbane

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    Three months journeying of a Hawaiian monk seal

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    Hawaiian monk seals (Monachus schauinslandi) are endemic to the Hawaiian Islands and are the most endangered species of marine mammal that lives entirely within the jurisdiction of the United States. The species numbers around 1300 and has been declining owing, among other things, to poor juvenile survival which is evidently related to poor foraging success. Consequently, data have been collected recently on the foraging habitats, movements, and behaviors of monk seals throughout the Northwestern and main Hawaiian Islands. Our work here is directed to exploring a data set located in a relatively shallow offshore submerged bank (Penguin Bank) in our search of a model for a seal's journey. The work ends by fitting a stochastic differential equation (SDE) that mimics some aspects of the behavior of seals by working with location data collected for one seal. The SDE is found by developing a time varying potential function with two points of attraction. The times of location are irregularly spaced and not close together geographically, leading to some difficulties of interpretation. Synthetic plots generated using the model are employed to assess its reasonableness spatially and temporally. One aspect is that the animal stays mainly southwest of Molokai. The work led to the estimation of the lengths and locations of the seal's foraging trips.Comment: Published in at http://dx.doi.org/10.1214/193940307000000473 the IMS Collections (http://www.imstat.org/publications/imscollections.htm) by the Institute of Mathematical Statistics (http://www.imstat.org

    High efficiency SiO2-TiO2 hybrid sol-gel antireflective coating for infrared applications

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    Sol-gel derived antireflective thin films were created for chalcogenide glass substrates in the 1.5-5 mu m wavelength range of infrared region. Presented herein is a preparation and characterization of the hybrid sol-gel created including particle size, refractive index, pH, and Fourier transform infrared FTIR transmission spectra. It is shown that an increase of not less than 8% and up to 25.1% transmission is achieved using sol-gel derived antireflective coatings

    Band gap energy modifications observed in trivalent In substituted nanocrystalline SnO2

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    The effect of In doping concentration on the optical band gap of nano-SnO2 is investigated as a function of calcination temperature. Changes in the band gap explain the room temperature H-2 gas sensing of doped nano-SnO2. The band gap was found to be lower than those reported for SnO2 (3.6 eV) from 2.55 to 3.43 eV and may be explained by the presence of nonequilibrium oxygen vacancies in the oxide lattice and band bending effects at the nanoscale

    A Study of Heavy-Light Mesons on the Transverse Lattice

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    We present results from a study of meson spectra and structure in the limit where one quark is infinitely heavy. The calculations, based on the framework of light-front QCD formulated on a transverse lattice, are the first non-perturbative studies of B-mesons in light-front QCD. We calculate the Isgur-Wise form factor, light-cone distribution amplitude, the heavy-quark parton distribution function and the leptonic decay constant of B-mesons.Comment: 5 pages, 3 figures, Revtex, corrected typos, added references, included moment

    Direct Measurement of Periodic Electric Forces in Liquids

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    The electric forces acting on an atomic force microscope tip in solution have been measured using a microelectrochemical cell formed by two periodically biased electrodes. The forces were measured as a function of lift height and bias amplitude and frequency, providing insight into electrostatic interactions in liquids. Real-space mapping of the vertical and lateral components of electrostatic forces acting on the tip from the deflection and torsion of the cantilever is demonstrated. This method enables direct probing of electrostatic and convective forces involved in electrophoretic and dielectroforetic self-assembly and electrical tweezer operation in liquid environments

    Surface elastic properties of porous nanosilica coatings by scanning force microscopy

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    Surface elastic properties of sol-gel derived porous nanosilica optical coatings were determined using scanning force microscopy. Silica nanocoatings prepared under acid and base catalyzed sol-gel process exhibited varying surface morphology, particle size and porosity. Force-distance spectroscopy measurements were conducted on these coatings using scanning force microscopy, and their elastic moduli were obtained by applying Hertz model. The elastic modulus of the coatings varied from 2.4 to 13.4 GPa depending on the nature and concentration of the catalyst used
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