45,144 research outputs found

    Extraction of nuclear matter properties from nuclear masses by a model of equation of state

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    The extraction of nuclear matter properties from measured nuclear masses is investigated in the energy density functional formalism of nuclei. It is shown that the volume energy a1a_1 and the nuclear incompressibility K0K_0 depend essentially on μnN+μˉpZ2EN\mu_n N+\bar{\mu}_p Z-2E_N, whereas the symmetry energy JJ and the density symmetry coefficient LL as well as symmetry incompressibility KsK_s depend essentially on μnμˉp\mu_n-\bar{\mu}_p, where μˉp=μpEC/Z\bar{\mu}_p=\mu_p-\partial E_C/\partial Z, μn\mu_n and μp\mu_p are the neutron and proton chemical potentials respectively, ENE_N the nuclear energy, and ECE_C the Coulomb energy. The obtained symmetry energy is J=28.5MeVJ=28.5MeV, while other coefficients are uncertain within ranges depending on the model of nuclear equation of state.Comment: 12 pages and 7 figure

    Zero-shot keyword spotting for visual speech recognition in-the-wild

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    Visual keyword spotting (KWS) is the problem of estimating whether a text query occurs in a given recording using only video information. This paper focuses on visual KWS for words unseen during training, a real-world, practical setting which so far has received no attention by the community. To this end, we devise an end-to-end architecture comprising (a) a state-of-the-art visual feature extractor based on spatiotemporal Residual Networks, (b) a grapheme-to-phoneme model based on sequence-to-sequence neural networks, and (c) a stack of recurrent neural networks which learn how to correlate visual features with the keyword representation. Different to prior works on KWS, which try to learn word representations merely from sequences of graphemes (i.e. letters), we propose the use of a grapheme-to-phoneme encoder-decoder model which learns how to map words to their pronunciation. We demonstrate that our system obtains very promising visual-only KWS results on the challenging LRS2 database, for keywords unseen during training. We also show that our system outperforms a baseline which addresses KWS via automatic speech recognition (ASR), while it drastically improves over other recently proposed ASR-free KWS methods.Comment: Accepted at ECCV-201

    Specific volumes of the Zr41.2Ti13.8Cu12.5Ni10.0Be22.5 alloy in the liquid, glass, and crystalline states

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    The specific volumes of the Zr41.2Ti13.8CU12.5Ni10.0Be2.25 alloy as a function of temperature, T, are determined by employing an image digitizing technique and numerical calculation methods applied to the electrostatically levitated spherical alloy. The linear fitting of the volumes of the alloy in the liquid, V-l, glass, V-g, and crystalline V-c, states in the temperature ranges shown in parentheses are V-l(T) = 0.1583 + 8.877 x 10(-6)T(cm^(3)/g) (700-1300 K); V-g(T) = 0.1603 + 5.528 x 10^(-6)T (400-550 K); V-c(T) = 0.1583 + 6.211 x 10(-6)T(400-850 K). The average volume thermal expansion coefficients within the temperature ranges are determined to be 5.32, 3.39, and 3.83 x 10^(-5) (1/K) for the liquid, glass, and crystalline states, respectively

    Induced Lorentz- and CPT-violating Chern-Simons term in QED: Fock-Schwinger proper time method

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    Using the Fock-Schwinger proper time method, we calculate the induced Chern-Simons term arising from the Lorentz- and CPT-violating sector of quantum electrodynamics with a bμψˉγμγ5ψb_\mu \bar{\psi}\gamma^\mu \gamma_5 \psi term. Our result to all orders in bb coincides with a recent linear-in-bb calculation by Chaichian et al. [hep-th/0010129 v2]. The coincidence was pointed out by Chung [Phys. Lett. {\bf B461} (1999) 138] and P\'{e}rez-Victoria [Phys. Rev. Lett. {\bf 83} (1999) 2518] in the standard Feynman diagram calculation with the nonperturbative-in-bb propagator.Comment: 11 pages, no figur

    Erratum: Dynamics and scaling in a quantum spin chain material with bond randomness

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    Follow-up neutron measurements, performed on a sample much larger than the one used in the original study, show that in the energy range 0.5-45 meV the magnetic excitations in BaCu2SiGeO7 are indistinguishable from those in conventional (disorder-free) quantum S=1/2 chains. Scrutinizing the previous data, we found that the analysis was affected by a poorly identified structured background and an additional technical mistake in the data reduction.Comment: This is a complete withdrawal of the original paper, also published as in Phys. Rev. Lett 93, 077206 (2004). One page, one figur

    Effective nucleon-nucleon interactions and nuclear matter equation of state

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    Nuclear matter equations of state based on Skyrme, Myers-Swiatecki and Tondeur interactions are written as polynomials of the cubic root of density, with coefficients that are functions of the relative neutron excess δ\delta. In the extrapolation toward states far away from the standard one, it is shown that the asymmetry dependence of the critical point (ρc,δc\rho_c, \delta_c) depends on the model used. However, when the equations of state are fitted to the same standard state, the value of δc\delta_c is almost the same in Skyrme and in Myers-Swiatecki interactions, while is much lower in Tondeur interaction. Furthermore, δc\delta_c does not depend sensitively on the choice of the parameter γ\gamma in Skyrme interaction.Comment: 15 pages, 9 figure

    Adjacency labeling schemes and induced-universal graphs

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    We describe a way of assigning labels to the vertices of any undirected graph on up to nn vertices, each composed of n/2+O(1)n/2+O(1) bits, such that given the labels of two vertices, and no other information regarding the graph, it is possible to decide whether or not the vertices are adjacent in the graph. This is optimal, up to an additive constant, and constitutes the first improvement in almost 50 years of an n/2+O(logn)n/2+O(\log n) bound of Moon. As a consequence, we obtain an induced-universal graph for nn-vertex graphs containing only O(2n/2)O(2^{n/2}) vertices, which is optimal up to a multiplicative constant, solving an open problem of Vizing from 1968. We obtain similar tight results for directed graphs, tournaments and bipartite graphs

    Nuclear matter properties and relativistic mean-field theory

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    Nuclear matter properties are calculated in the relativistic mean field theory by using a number of different parameter sets. The result shows that the volume energy a1a_1 and the symmetry energy JJ are around the acceptable values 16MeV and 30MeV respectively; the incompressibility K0K_0 is unacceptably high in the linear model, but assumes reasonable value if nonlinear terms are included; the density symmetry LL is around 100MeV100MeV for most parameter sets, and the symmetry incompressibility KsK_s has positive sign which is opposite to expectations based on the nonrelativistic model. In almost all parameter sets there exists a critical point (ρc,δc)(\rho_c, \delta_c), where the minimum and the maximum of the equation of state are coincident and the incompressibility equals zero, falling into ranges 0.014fm3<ρc<0.039^{-3}<\rho_c<0.039fm3^{-3} and 0.74<δc0.950.74<\delta_c\le0.95; for a few parameter sets there is no critical point and the pure neutron matter is predicted to be bound. The maximum mass MNSM_{NS} of neutron stars is predicted in the range 2.45MMNS3.26_\odot\leq M_{NS}\leq 3.26M_\odot, the corresponding neutron star radius RNSR_{NS} is in the range 12.2kmRNS15.1\leq R_{NS}\leq 15.1km.Comment: 10 pages, 5 figure
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