P/N InP homojunction solar cells by LPE and MOCVD techniques

P/N InP homojunction solar cells have been prepared by using both liquid phase epitaxy (LPE) and metallorganic chemical vapor deposition (MOCVD) growth techniques. A heavily doped p-In sub 0.53Ga sub 0.47As contacting layer was incorporated into the cell structure to improve the fill factor and to eliminate surface spiking at the front surface. The best conversion efficiencies (total area) obtained under AM 1 illumination are 14.2 percent for a LPE cell and 15.4 percent for a MOCVD cell

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

Thermo-acoustic wave propagation and reflection near the liquid-gas critical point

We study the thermo-acoustic wave propagation and reflection near the liquid-gas critical point. Specifically, we perform a numerical investigation of the acoustic responses in a near-critical fluid to thermal perturbations based on the same setup of a recent ultrasensitive interferometry measurement in CO2 [Y. Miura et al. Phys. Rev. E 74, 010101(R) (2006)]. The numerical results agree well with the experimental data. New features regarding the reflection pattern of thermo-acoustic waves near the critical point under pulse perturbations are revealed by the proper inclusion of the critically diverging bulk viscosity.Comment: 14 pages, 4 figures, Accepted by PRE (Rapid Communication

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

Application of density dependent parametrization models to asymmetric nuclear matter

Density dependent parametrization models of the nucleon-meson effective couplings, including the isovector scalar \delta-field, are applied to asymmetric nuclear matter. The nuclear equation of state and the neutron star properties are studied in an effective Lagrangian density approach, using the relativistic mean field hadron theory. It is known that the introduction of a \delta-meson in the constant coupling scheme leads to an increase of the symmetry energy at high density and so to larger neutron star masses, in a pure nucleon-lepton scheme. We use here a more microscopic density dependent model of the nucleon-meson couplings to study the properties of neutron star matter and to re-examine the \delta-field effects in asymmetric nuclear matter. Our calculations show that, due to the increase of the effective \delta coupling at high density, with density dependent couplings the neutron star masses in fact can be even reduced.Comment: 5 pages, 4 figure