Pentaquark Θ+\Theta^+ in nuclear matter and Θ+\Theta^+ hypernuclei

We study the properties of the $\Theta^+$ in nuclear matter and $\Theta^+$ hypernuclei within the quark mean-field (QMF) model, which has been successfully used for the description of ordinary nuclei and $\Lambda$ hypernuclei. With the assumption that the non-strange mesons couple only to the $u$ and $d$ quarks inside baryons, a sizable attractive potential of the $\Theta^+$ in nuclear matter is achieved as a consequence of the cancellation between the attractive scalar potential and the repulsive vector potential. We investigate the $\Theta^+$ single-particle energies in light, medium, and heavy nuclei. More bound states are obtained in $\Theta^+$ hypernuclei in comparison with those in $\Lambda$ hypernuclei.Comment: 16 pages, 5 figure

TEM investigation of YBa2Cu3O7 thin films on SrTiO3 bicrystals

YBa2Cu3O7 films in c-axis orientation on bicrystalline SrTiO3 substrates are investigated by TEM. The films and the substrates are examined in cross-section and in plane view. The grain boundary of the bicrystal substrate contains (110) faceted voids, but is otherwise straight on a nanometer scale. Contrary to this, the film grain boundary is not straight grain boundary can be up to 100 nm for a 100 nm thick film. The deviation from the intended position of the YBCO grain boundary can already occur at the film/substrate interface where it can be as much as ±50 nm

Neutron star matter in the quark-meson coupling model in strong magnetic fields

The effects of strong magnetic fields on neutron star matter are investigated in the quark-meson coupling (QMC) model. The QMC model describes a nuclear many-body system as nonoverlapping MIT bags in which quarks interact through self-consistent exchange of scalar and vector mesons in the mean-field approximation. The results of the QMC model are compared with those obtained in a relativistic mean-field (RMF) model. It is found that quantitative differences exist between the QMC and RMF models, while qualitative trends of the magnetic field effects on the equation of state and composition of neutron star matter are very similar.Comment: 16 pages, 4 figure

Anomalous high energy dispersion in photoemission spectra from insulating cuprates

Angle resolved photoelectron spectroscopic measurements have been performed on an insulating cuprate Ca_2CuO_2Cl_2. High resolution data taken along the \Gamma to (pi,pi) cut show an additional dispersive feature that merges with the known dispersion of the lowest binding energy feature, which follows the usual strongly renormalized dispersion of ~0.35 eV. This higher energy part reveals a dispersion that is very close to the unrenormalized band predicted by band theory. A transfer of spectral weight from the low energy feature to the high energy feature is observed as the \Gamma point is approached. By comparing with theoretical calculations the high energy feature observed here demonstrates that the incoherent portion of the spectral function has significant structure in momentum space due to the presence of various energy scales.Comment: 5 pages, 3 figure

An improved approximation algorithm for computing disjoint QoS paths

©2006 IEEE. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE.The survivability of a network has assumed great importance in against of losing huge volumes of data due to a link cut or node failure. Recently some scholars have proposed some path restoration schemes which used two disjoint paths with multiple constraints to satisfy both the survivability and the QoS requirements. In this paper we will study the issue of how to identify two paths that satisfy the multiple QoS constraints imposed by network applications. More specifically, we will focus on finding two link-disjoint paths that satisfy the delay constraints at a reasonable total cost. We present two efficient approximation algorithms with provable performance guarantees for this problem.Chao Peng, Hong She

NIMBUS-5 sounder data processing system. Part 2: Results

The Nimbus-5 spacecraft carries infrared and microwave radiometers for sensing the temperature distribution of the atmosphere. Methods developed for obtaining temperature profiles from the combined set of infrared and microwave radiation measurements are described. Algorithms used to determine (a) vertical temperature and water vapor profiles, (b) cloud height, fractional coverage, and liquid water content, (c) surface temperature, and (d) total outgoing longwave radiation flux are described. Various meteorological results obtained from the application of the Nimbus-5 sounding data processing system during 1973 and 1974 are presented