2,764 research outputs found

    Improvement of Production Rate of YBCO Coated Conductors Fabricated by TFA-MOD Method

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    AbstractThe metal-organic deposition (MOD) method using trifluoroacetate (TFA) salts is considered to be an effective method for inexpensively fabricating YBa2Cu3O7-y (YBCO) coated conductors with high critical current density property. The long-length TFA-MOD YBCO coated conductors have been fabricated by multi-turn reel-to-reel system. Increasing the thickness per single coating in the multi-turn reel-to-reel system is a cost-effective technique for fabrication of the precursor films in the calcination process since it reduces the number of coatings and shortens the processing time. In this work, we have developed a new starting solution consisting of non-fluorine salts of yttrium propionate and copper 2-ethylhexanoate with focusing on increasing the thickness per single coating for a high-rate fabrication of the YBCO coated conductors by the TFA-MOD method. The critical thickness per single coating of the precursor film fabricated from the new starting solution was improved to 0.44μm/coat. Furthermore, the addition of diacetoneacrylamide in the new starting solution increased the critical thickness per single coating to 0.79μm/coat. High critical current of 791 A/cm-width with high critical current density of 2.7 MA/cm2 was obtained using the new starting solution with diacetoneacrylamide at the thickness per single coating of 0.49μm/coat

    VEGF(164)-mediated inflammation is required for pathological, but not physiological, ischemia-induced retinal neovascularization

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    Hypoxia-induced VEGF governs both physiological retinal vascular development and pathological retinal neovascularization. In the current paper, the mechanisms of physiological and pathological neovascularization are compared and contrasted. During pathological neovascularization, both the absolute and relative expression levels for VEGF(164) increased to a greater degree than during physiological neovascularization. Furthermore, extensive leukocyte adhesion was observed at the leading edge of pathological, but not physiological, neovascularization. When a VEGF(164)-specific neutralizing aptamer was administered, it potently suppressed the leukocyte adhesion and pathological neovascularization, whereas it had little or no effect on physiological neovascularization. In parallel experiments, genetically altered VEGF(164)-deficient (VEGF(120/188)) mice exhibited no difference in physiological neovascularization when compared with wild-type (VEGF(+/+)) controls. In contrast, administration of a VEGFk-1/Fc fusion protein, which blocks all VEGF isoforms, led to significant suppression of both pathological and physiological neovascularization. In addition, the targeted inactivation of monocyte lineage cells with clodronate-liposomes led to the suppression of pathological neovascularization. Conversely, the blockade of T lymphocyte-mediated immune responses with an anti-CD2 antibody exacerbated pathological neovascularization. These data highlight important molecular and cellular differences between physiological and pathological retinal neovascularization. During pathological neovascularization, VEGF(164) selectively induces inflammation and cellular immunity. These processes provide positive and negative angiogenic regulation, respectively. Together, new therapeutic approaches for selectively targeting pathological, but not physiological, retinal neovascularization are outlined

    Cassini's floating potential in Titan's ionosphere: 3-D particle-in-cell simulations

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    Accurate determination of Cassini’s spacecraft potential in Titan’s ionosphere is important for interpreting measurements by its low energy plasma instruments. Estimates of the floating potential varied significantly, however, between the various different plasma instruments. In this study we utilize 3-D particle-in-cell simulations to understand the key features of Cassini’s plasma interaction in Titan’s ionosphere. The spacecraft is observed to charge to negative potentials for all scenarios considered, and close agreement is found between the current onto the simulated Langmuir Probe and that observed in Titan’s ionosphere. These simulations are therefore shown to provide a viable technique for modeling spacecraft interacting with Titan’s dusty ionosphere

    Presence of contagious yawning in children with Autism Spectrum Disorder

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    Most previous studies suggest diminished susceptibility to contagious yawning in children with autism spectrum disorder (ASD). However, it could be driven by their atypical attention to the face. To test this hypothesis, children with ASD and typically developing (TD) children were shown yawning and control movies. To ensure participants' attention to the face, an eye tracker controlled the onset of the yawning and control stimuli. Results demonstrated that both TD children and children with ASD yawned more frequently when they watched the yawning stimuli than the control stimuli. It is suggested therefore that the absence of contagious yawning in children with ASD, as reported in previous studies, might relate to their weaker tendency to spontaneously attend to others' faces

    Proximity to Fermi-surface topological change in superconducting LaO0.54F0.46BiS2

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    The electronic structure of nearly optimally-doped novel superconductor LaO1−x_{1-x}Fx_xBiS2_2 (x{\it x} = 0.46) was investigated using angle-resolved photoemission spectroscopy (ARPES). We clearly observed band dispersions from 2 to 6 eV binding energy and near the Fermi level (EF{\it E}_{\rm F}), which are well reproduced by first principles calculations when the spin-orbit coupling is taken into account. The ARPES intensity map near EF{\it E}_{\rm F} shows a square-like distribution around the Γ\Gamma(Z) point in addition to electronlike Fermi surface (FS) sheets around the X(R) point, indicating that FS of LaO0.54_{0.54}F0.46_{0.46}BiS2_2 is in close proximity to the theoretically-predicted topological change.Comment: 6 pages, 3 figures, + supplemental materia

    Incommensurate spin fluctuations in hole-overdoped superconductor KFe2As2

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    A neutron scattering study of heavily hole-overdoped superconducting KFe2_2As2_2 revealed a well-defined low-energy incommensurate spin fluctuation at [π(1±2δ\pi(1\pm2\delta),0] with δ\delta = 0.16. The incommensurate structure differs from the previously observed commensurate peaks in electron-doped AAFe2_2As2_2 (AA = Ba, Ca, or Sr) at low energies. The direction of the peak splitting is perpendicular to that observed in Fe(Te,Se) or in Ba(Fe,Co)2_2As2_2 at high energies. A band structure calculation suggests interband scattering between bands around the Γ\Gamma and X points as an origin of this incommensurate peak. The perpendicular direction of the peak splitting can be understood within the framework of multiorbital band structure. The results suggest that spin fluctuation is more robust in hole-doped than in electron-doped samples, which can be responsible for the appearance of superconductivity in the heavily hole-doped samples.Comment: 4 pages, 4 figure
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