Isovector part of nuclear energy density functional from chiral two- and three-nucleon forces

A recent calculation of the nuclear energy density functional from chiral two- and three-nucleon forces is extended to the isovector terms pertaining to different proton and neutron densities. An improved density-matrix expansion is adapted to the situation of small isospin-asymmetries and used to calculate in the Hartree-Fock approximation the density-dependent strength functions associated with the isovector terms. The two-body interaction comprises of long-range multi-pion exchange contributions and a set of contact terms contributing up to fourth power in momenta. In addition, the leading order chiral three-nucleon interaction is employed with its parameters fixed in computations of nuclear few-body systems. With this input one finds for the asymmetry energy of nuclear matter the value $A(\rho_0) \simeq 26.5\,$MeV, compatible with existing semi-empirical determinations. The strength functions of the isovector surface and spin-orbit coupling terms come out much smaller than those of the analogous isoscalar coupling terms and in the relevant density range one finds agreement with phenomenological Skyrme forces. The specific isospin- and density-dependences arising from the chiral two- and three-nucleon interactions can be explored and tested in neutron-rich systems.Comment: 14 pages, 7 figures, to be published in European Physical Journal

Dielectric signature of charge order in lanthanum nickelates

Three charge-ordering lanthanum nickelates La2-xAxNiO4, substituted with specific amounts of A = Sr, Ca, and Ba to achieve commensurate charge order, are investigated using broadband dielectric spectroscopy up to GHz frequencies. The transition temperatures of the samples are characterized by additional specific heat and magnetic susceptibility measurements. We find colossal magnitudes of the dielectric constant for all three compounds and strong relaxation features, which partly are of Maxwell-Wagner type arising from electrode polarization. Quite unexpectedly, the temperature-dependent colossal dielectric constants of these materials exhibit distinct anomalies at the charge-order transitions.Comment: 7 pages, 6 figure

Brandverhalten von Stahltrapezprofildaechern mit harter Bedachung -Dachdurchbrueche

Available from TIB Hannover: F94B1809 / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEStifterverband fuer die Deutsche Wissenschaft e.V., Essen (Germany). Stiftung StahlanwendungsforschungDEGerman

Spatial distribution of soft-bottom molluscs in the Ensenada de San Simón (NW Spain)

11 páginasDistribution and abundance of the molluscan fauna was studied in the intertidal and subtidal soft-bottoms of the Ensenada de San Simón (NW Spain). Depth, grain size, and total organic matter were the most important factors in determining distribution patterns of molluscs in this inlet. Three major malacological assemblages have been determined in the Ensenada de San Simón, two of them subdivided in two facies. In the intertidal area of the inlet, one facies (A1) was located in areas associated with seagrass meadows of Zostera spp. and was dominated by Hydrobia ulvae (Pennant, 1777) whereas the second facies (A2) had a high dominance of H. ulvae, Cerastoderma edule (Linnaeus, 1758), and Tapes decussatus (Linnaeus, 1758). An impoverished facies of this community was present in reduced, muddy bottoms (Group C). In the subtidal bottoms, one group (B1) was located in the central part of the inlet with H. ulvae, Rissoa labiosa (Montagu, 1803), Turboella radiata (Philippi, 1836), Parvicardium exiguum (Gmelin in Linnaeus, 1791), Loripes lacteus (Linnaeus, 1758), and Abra nitida (Müller, 1789) as characteristic species. A second facies (B2) was found in outer areas of the inlet, characterized by Thyasira flexuosa (Montagu, 1803), Mysella bidentata (Montagu, 1803), Abra alba (Wood, 1802), and Nucula nitidosa Winckworth, 1930.Peer reviewe

Gutachten ueber die Bemessung und Wirksamkeit von Rauch- und Waermeabzugsanlagen fuer unterirdische Garagen

TIB: RN 5905 (1827) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

Brandversuch zur Ueberpruefung der Leistungsfaehigkeit eines Druckbelueftungssystemes zur Rauchfreihaltung der Treppenraeume in einem Buerogebaeude

TIB: RN 5905 (953) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman