34,004 research outputs found

    Reactor Fuel Fraction Information on the Antineutrino Anomaly

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    We analyzed the evolution data of the Daya Bay reactor neutrino experiment in terms of short-baseline active-sterile neutrino oscillations taking into account the theoretical uncertainties of the reactor antineutrino fluxes. We found that oscillations are disfavored at 2.6σ2.6\sigma with respect to a suppression of the 235U^{235}\text{U} reactor antineutrino flux and at 2.5σ2.5\sigma with respect to variations of the 235U^{235}\text{U} and 239Pu^{239}\text{Pu} fluxes. On the other hand, the analysis of the rates of the short-baseline reactor neutrino experiments favor active-sterile neutrino oscillations and disfavor the suppression of the 235U^{235}\text{U} flux at 3.1σ3.1\sigma and variations of the 235U^{235}\text{U} and 239Pu^{239}\text{Pu} fluxes at 2.8σ2.8\sigma. We also found that both the Daya Bay evolution data and the global rate data are well-fitted with composite hypotheses including variations of the 235U^{235}\text{U} or 239Pu^{239}\text{Pu} fluxes in addition to active-sterile neutrino oscillations. A combined analysis of the Daya Bay evolution data and the global rate data shows a slight preference for oscillations with respect to variations of the 235U^{235}\text{U} and 239Pu^{239}\text{Pu} fluxes. However, the best fits of the combined data are given by the composite models, with a preference for the model with an enhancement of the 239Pu^{239}\text{Pu} flux and relatively large oscillations.Comment: 9 page

    Effect of ludwigite (B2O3) on high Al2O3 slag and its mechanism used as a new blast furnace welding flux

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    Based on the measurement of viscosities and critical temperatures of CaO-MgO-SiO2- Al2O3-B2O3 slag system with various B2O3 contents, the slag with higher than 15 mas. % Al2O3 content has the lowest critical temperature and the widest solid-liquid coexisting region at about 2,0 mas. % B2O3. Furthermore, the X-ray diffractometer (XRD) result verified that bechilites whose melting point are low forms. Raman spectra revealed that the effect of network forming on viscosity is smaller than the effect of bechilites, which leads to the slag viscosity decrease with B2O3 addition. Base on the above research, so ludwigite can meet the requirements of a BF welding flux to decrease the critical temperature and improve the fluidity of the high Al2O3 slag

    Electromagnetic fields in a 3D cavity and in a waveguide with oscillating walls

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    We consider classical and quantum electromagnetic fields in a three-dimensional (3D) cavity and in a waveguide with oscillating boundaries of the frequency Ω\Omega . The photons created by the parametric resonance are distributed in the wave number space around Ω/2\Omega/2 along the axis of the oscillation. When classical waves propagate along the waveguide in the one direction, we observe the amplification of the original waves and another wave generation in the opposite direction by the oscillation of side walls. This can be understood as the classical counterpart of the photon production. In the case of two opposite walls oscillating with the same frequency but with a phase difference, the interferences are shown to occur due to the phase difference in the photon numbers and in the intensity of the generated waves.Comment: 8 pages revTeX including 1 eps fi

    Density functional calculations of the electronic structure and magnetic properties of the hydrocarbon K3picene superconductor near the metal-insulator transition

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    We have investigated the electronic structures and magnetic properties of of K3picene, which is a first hydrocarbon superconductor with high transition temperature T_c=18K. We have shown that the metal-insulator transition (MIT) is driven in K3picene by 5% volume enhancement with a formation of local magnetic moment. Active bands for superconductivity near the Fermi level E_F are found to have hybridized character of LUMO and LUMO+1 picene molecular orbitals. Fermi surfaces of K3picene manifest neither prominent nesting feature nor marked two-dimensional behavior. By estimating the ratio of the Coulomb interaction U and the band width W of the active bands near E_F, U/W, we have demonstrated that K3picene is located in the vicinity of the Mott transition.Comment: 5 pages, 5 figure

    Properties of MnO on high Al2O3 slag and its mechanism used for flushing blast furnace (BF)

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    Flushing blast furnace by manganese ore was one of the important methods to recover the hearth inactivity caused by hearth accumulation. In this work, the properties and mechanism of the slag with different MnO content were researched, including the viscosity and critical temperature measured by rotating cylinder method, the mineral phase and microstructure confirmed by X-ray diffraction (XRD), scanning electronic microscopy (SEM) and fourier transform infrared spectrometer (FTIR). The experiment results showed that during the process of flushing blast furnace, the appropriate and optimal MnO in the slag was 1,5 to 2,0 mas .%, the mechanism of flushing by MnO was that the tephroite whose melting point is low forms, the depolymerization of [SiO4]-tetrahedral structure caused by MnO addition also plays an important role in reducing the viscosity of the slag

    Spin dynamics and magnetic interactions of Mn dopants in the topological insulator Bi2_2Te3_3

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    The magnetic and electronic properties of the magnetically doped topological insulator Bi2x_{\rm 2-x}Mnx_{\rm x}Te3_3 were studied using electron spin resonance (ESR) and measurements of static magnetization and electrical transport. The investigated high quality single crystals of Bi2x_{\rm 2-x}Mnx_{\rm x}Te3_3 show a ferromagnetic phase transition for x0.04x\geq 0.04 at TC12T_{C}\approx 12 K. The Hall measurements reveal a p-type finite charge-carrier density. Measurements of the temperature dependence of the ESR signal of Mn dopants for different orientations of the external magnetic field give evidence that the localized Mn moments interact with the mobile charge carriers leading to a Ruderman-Kittel-Kasuya-Yosida-type ferromagnetic coupling between the Mn spins of order 2-3 meV. Furthermore, ESR reveals a low-dimensional character of magnetic correlations that persist far above the ferromagnetic ordering temperature
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