3,002 research outputs found

    Universal R-matrix Of The Super Yangian Double DY(gl(1|1))

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    Based on Drinfeld realization of super Yangian Double DY(gl(1|1)), its pairing relations and universal R-matrix are given. By taking evaluation representation of universal R-matrix, another realization L±(u)L^{\pm}(u) of DY(gl(1|1)) is obtained. These two realizations of DY(gl(1|1)) are related by the supersymmetric extension of Ding-Frenkel map.Comment: 6 pages, latex, no figure

    A WENO Algorithm of the Temperature and Ionization Profiles around a Point Source

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    We develop a numerical solver for radiative transfer problems based on the weighted essentially nonoscillatory (WENO) scheme modified with anti-diffusive flux corrections, in order to solve the temperature and ionization profiles around a point source of photons in the reionization epoch. Algorithms for such simulation must be able to handle the following two features: 1. the sharp profiles of ionization and temperature at the ionizing front (I-front) and the heating front (T-front), and 2. the fraction of neutral hydrogen within the ionized sphere is extremely small due to the stiffness of the rate equations of atom processes. The WENO scheme can properly handle these two features, as it has been shown to have high order of accuracy and good convergence in capturing discontinuities and complicated structures in fluid as well as to be significantly superior over piecewise smooth solutions containing discontinuities. With this algorithm, we show the time-dependence of the preheated shell around a UV photon source. In the first stage the I-front and T-front are coincident, and propagate with almost the speed of light. In later stage, when the frequency spectrum of UV photons is hardened, the speeds of propagation of the ionizing and heating fronts are both significantly less than the speed of light, and the heating front is always beyond the ionizing front. In the spherical shell between the I- and T-fronts, the IGM is heated, while atoms keep almost neutral. The time scale of the preheated shell evolution is dependent on the intensity of the photon source. We also find that the details of the pre-heated shell and the distribution of neutral hydrogen remained in the ionized sphere are actually sensitive to the parameters used. The WENO algorithm can provide stable and robust solutions to study these details.Comment: 24 pages, 7 figures, accepted in New Astronom

    Who is in charge and whose rules are followed..?: Power in a inter-organisational IS project

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    While Enterprise Resource Planning (ERP) system demand in China has been steadily increasing, many of such implementation projects failed. Keda Industrial Co. Ltd (600986: Shanghai Stock Exchange), a manufacturer of large scale machinery in China, however, was one of the few that successfully deployed its ERP solution in 2005. In this case study, we document the ERP initiative of Keda from its conception to its deployment, study the factors that contributed to its success, and summarize Keda’s practices that substantiated the identified success factors

    Identification of non-specific lipid transfer protein-1 as a calmodulin-binding protein in Arabidopsis

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    AbstractAlthough non-specific lipid transfer proteins (nsLTPs) are widely present in plants, their functions and regulations have not been fully understood. In this report, Arabidopsis nsLTP1 was cloned and expressed to investigate its binding to calmodulin (CaM). Gel overlay assays revealed that recombinant nsLTP1 bound to CaM in a calcium-independent manner. The association of nsLTP1 and CaM was corroborated using CaM–Sepharose beads to specifically isolate recombinant nsLTP1 from crude bacterial lysate. The CaM-binding site was mapped in nsLTP1 to the region of 69–80 amino acids. This region is highly conserved among plant nsLTPs, implicating that nsLTPs are a new family of CaM-binding proteins whose functions may be mediated by CaM signaling

    Early Defervescence and SARS Recovery

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    Facile hydrothermal synthesis and optical limiting properties of TiO 2 -reduced graphene oxide nanocomposites

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    TiO2/reduced graphene oxide (RGO) nanocomposites Gx (RGO titania nanocomposite, x grams tetrabutyl titanate per 0.03 g RGO, x = 0.25, 0.50, 1.00) were prepared by a hydrothermal method: graphene oxide was reduced to RGO in a 2:1 water:ethanol mixture in the presence of varying quantities of tetrabutyl titanate, which deposited as TiO2 on the RGO sheets. The nanocomposites were characterized by a combination of Fourier transform infrared spectroscopy, diffuse reflectance ultraviolet-visible spectroscopy, photoluminescence spectroscopy, Raman spectroscopy, X-ray powder diffraction, X-ray photoelectron spectroscopy and transmission electron microscopy studies. The nanocomposite G0.25 exhibits enhanced nonlinear optical properties compared to its individual components, which is ascribed to a combination of mechanisms. The role of defects and electron/energy transfer in the optical limiting performance of G0.25 was clarified with the help of Raman and photoluminescence spectroscopies. Intensity-dependent switching between reverse saturable absorption and saturable absorption behavior was observed with the G0.50 nanocomposite
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