94,772 research outputs found

    Investigation on influential factors on chloride concentration index of cement-based materials by pore solution expression method

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    In this study, the effects of different factors on chloride concentration index (N-c) of cement paste were studied. The factors including chloride concentration in soaking solution, slag replacement, external applied voltage and cation ions of soaking solution were all studied from the electrical double layer (EDL) properties point of view. Zeta potential and proton Nuclear Magnetic Resonance (H-1 NMR) measurements were conducted to investigate the properties of electrical double layer for cement paste specimens and their effects on the value of chloride concentration index. The results showed that these factors all impacted effects on chloride concentration in electrical double layer and chloride concentration index. The properties of electrical double layer including chloride distribution and thickness of electrical double layer mainly controlled the phenomenon of "chloride concentrate" and value of chloride concentration index. As the increase of zeta potential and electrical double layer thickness, the content of chloride ions in electrical double layer and the value of chloride concentration index gradually increased. (C) 2019 Elsevier Ltd. All rights reserved

    Theory of time-resolved spectral function in high-temperature superconductors with bosonic modes

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    We develop a three-temperature model to simulate the time dependence of electron and phonon temperatures in high-temperature superconductors displaying strong anistropic electron-phonon coupling. This model not only takes the tight-binding band structure into account, but also is valid in superconducting state. Based on this model, we calculate the time-resolved spectral function via the double-time Green's functions. We find that the dip-hump structure evolves with the time delay. More interestingly, new phononic structures are obtained when the phonons are excited by a laser field. This signature may serve as a direct evidence for electron-vibration mode coupling.Comment: 5 pages, 3 figure

    Extended staggered-flux phases in two-dimensional lattices

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    Based on the so called tt-ϕ\phi model in two-dimensional (2D) lattices, we investigate the stabilities of a class of extended staggered-flux (SF) phases (which are the extensions of the 2×2\sqrt{2}\times\sqrt{2} SF phase to generalized spatial periods) against the Fermi-liquid phase. Surprisingly, when away from the nesting electron filling, some extended-SF phases take over the dominant SF phase (the 2×2\sqrt{2}\times\sqrt{2} SF phase for the square lattice, a 1×31\times\sqrt{3} SF phase for the triangular one), compete with the Fermi-liquid phase in nontrivial patterns, and still occupy significant space in the phase diagram through the advantage in the total electronic kinetic energies. The results can be termed as the generalized Perierls orbital-antiferromagnetic instabilities of the Fermi-liquid phase in 2D lattice-electron models.Comment: 5 pages, 5 figure

    OOGAN: Disentangling GAN with One-Hot Sampling and Orthogonal Regularization

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    Exploring the potential of GANs for unsupervised disentanglement learning, this paper proposes a novel GAN-based disentanglement framework with One-Hot Sampling and Orthogonal Regularization (OOGAN). While previous works mostly attempt to tackle disentanglement learning through VAE and seek to implicitly minimize the Total Correlation (TC) objective with various sorts of approximation methods, we show that GANs have a natural advantage in disentangling with an alternating latent variable (noise) sampling method that is straightforward and robust. Furthermore, we provide a brand-new perspective on designing the structure of the generator and discriminator, demonstrating that a minor structural change and an orthogonal regularization on model weights entails an improved disentanglement. Instead of experimenting on simple toy datasets, we conduct experiments on higher-resolution images and show that OOGAN greatly pushes the boundary of unsupervised disentanglement.Comment: AAAI 202

    A discrete chemo-dynamical model of the dwarf spheroidal galaxy Sculptor: mass profile, velocity anisotropy and internal rotation

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    We present a new discrete chemo-dynamical axisymmetric modeling technique, which we apply to the dwarf spheroidal galaxy Sculptor. The major improvement over previous Jeans models is that realistic chemical distributions are included directly in the dynamical modelling of the discrete data. This avoids loss of information due to spatial binning and eliminates the need for hard cuts to remove contaminants and to separate stars based on their chemical properties. Using a combined likelihood in position, metallicity and kinematics, we find that our models naturally separate Sculptor stars into a metal-rich and a metal-poor population. Allowing for non-spherical symmetry, our approach provides a central slope of the dark matter density of γ=0.5±0.3\gamma = 0.5 \pm 0.3. The metal-rich population is nearly isotropic (with βrred=0.0±0.1\beta_r^{red} = 0.0\pm0.1) while the metal-poor population is tangentially anisotropic (with βrblue=−0.2±0.1\beta_r^{blue} = -0.2\pm0.1) around the half light radius of 0.260.26 kpc. A weak internal rotation of the metal-rich population is revealed with vmax/σ0=0.15±0.15v_{max}/\sigma_0 = 0.15 \pm 0.15. We run tests using mock data to show that a discrete dataset with ∼6000\sim 6000 stars is required to distinguish between a core (γ=0\gamma = 0) and cusp (γ=1\gamma = 1), and to constrain the possible internal rotation to better than 1 σ1\,\sigma confidence with our model. We conclude that our discrete chemo-dynamical modelling technique provides a flexible and powerful tool to robustly constrain the internal dynamics of multiple populations, and the total mass distribution in a stellar system.Comment: Accepted by MNRA
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