47,816 research outputs found

    Bis[μ-bis(diphenylphosphino)methane-К²P:P’]bis[(saccharinato-КN)- palladium(I)] dichloromethane solvate

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    The dimeric palladium(I) saccharinate complex [Pd₂(sac)₂(dppm)₂], has been characterized as its di¬chloro¬methane solvate, i.e. [Pd₂(C₇H₄NO₃S)₂(C₂₅H₂₂P₂)₂]•CH₂Cl₂. The complex features a Pd—Pd bond bridged by two dppm ligands, with the saccharinate ligands N-bonded trans to the Pd—Pd bond

    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

    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

    Spectral Weights, d-wave Pairing Amplitudes, and Particle-hole Tunneling Asymmetry of a Strongly Correlated Superconductor

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    The spectral weights (SW's) for adding and removing an electron of the Gutzwiller projected d-wave superconducting (SC) state of the t-J-type models are studied numerically on finite lattices. Restrict to the uniform system but treat exactly the strong correlation between electrons, we show that the product of weights is equal to the pairing amplitude squared, same as in the weakly coupled case. In addition, we derive a rigorous relation of SW with doping in the electron doped system and obtain particle-hole asymmetry of the conductance-proportional quantity within the SC gap energy and, also, the anti-correlation between gap sizes and peak heights observed in tunneling spectroscopy on high Tc cuprates.Comment: 4 Revtex pages and 4 .eps figures. Published versio

    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

    Aspect-Based Sentiment Analysis Using a Two-Step Neural Network Architecture

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    The World Wide Web holds a wealth of information in the form of unstructured texts such as customer reviews for products, events and more. By extracting and analyzing the expressed opinions in customer reviews in a fine-grained way, valuable opportunities and insights for customers and businesses can be gained. We propose a neural network based system to address the task of Aspect-Based Sentiment Analysis to compete in Task 2 of the ESWC-2016 Challenge on Semantic Sentiment Analysis. Our proposed architecture divides the task in two subtasks: aspect term extraction and aspect-specific sentiment extraction. This approach is flexible in that it allows to address each subtask independently. As a first step, a recurrent neural network is used to extract aspects from a text by framing the problem as a sequence labeling task. In a second step, a recurrent network processes each extracted aspect with respect to its context and predicts a sentiment label. The system uses pretrained semantic word embedding features which we experimentally enhance with semantic knowledge extracted from WordNet. Further features extracted from SenticNet prove to be beneficial for the extraction of sentiment labels. As the best performing system in its category, our proposed system proves to be an effective approach for the Aspect-Based Sentiment Analysis

    Calculation of a Class of Three-Loop Vacuum Diagrams with Two Different Mass Values

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    We calculate analytically a class of three-loop vacuum diagrams with two different mass values, one of which is one-third as large as the other, using the method of Chetyrkin, Misiak, and M\"{u}nz in the dimensional regularization scheme. All pole terms in \epsilon=4-D (D being the space-time dimensions in a dimensional regularization scheme) plus finite terms containing the logarithm of mass are kept in our calculation of each diagram. It is shown that three-loop effective potential calculated using three-loop integrals obtained in this paper agrees, in the large-N limit, with the overlap part of leading-order (in the large-N limit) calculation of Coleman, Jackiw, and Politzer [Phys. Rev. D {\bf 10}, 2491 (1974)].Comment: RevTex, 15 pages, 4 postscript figures, minor corrections in K(c), Appendix B removed, typos corrected, acknowledgements change
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