We have calculated the evolution of 60 model binary systems consisting of helium stars in the mass range of MHe = 2.5 − 6M⊙ with a 1.4 M⊙ neutron star companion to investigate the formation of double neutron star systems. Orbital periods ranging from 0.09 to 2 days are considered, corresponding to Roche lobe overflow starting from the helium main sequence to after the ignition of carbon burning...

The population synthesis method is used to study the possibility of explaining the appreciable fraction of the intergalactic type-Ia supernovae (SN Ia), 20 −15%, observed in galaxy clusters (Gal-Yam et al. 2003) when close white dwarf binaries merge in the cores of globular clusters. In a typical globular cluster, the number of merging double white dwarfs does not exceed ∼ 10 per year per avera...

A compact double-balanced monolithic star mixer for Kaband applications using 0.25μm GaAs pHEMT process is presented. With multi-coupled lines technology, the proposed dual 180◦ hybrid is produced and applied to a star mixer successfully. The proposed hybrid adopts the power divider and two types of multi-coupled lines to improve the return loss and isolation at the balance outputs of a traditi...