The dual harmonic system has been widely used in high intensity proton synchrotrons to suppress the space charge effect, as well as reduce the beam loss. To investigate the longitudinal beam dynamics in the dual rf system, the potential well, the sub
-buckets in the bunch and the multi-solutions of the phase equation have been studied theoretically. Based on these theoretical studis, the optimization of bunching factor and rf voltage waveform are made for the dual harmonic rf system in the upgrade phase of the CSNS/RCS. In the optimization process, the simulation with space charge effect is done by using a newly developed code C-SCSIM.
Using a large sample of 26623 quasars with redshifts in the range $1.5 le zle 5.1$ with civ $lambda$1549 AA emission line in Fifth Data Release of the Sloan Digital Sky Survey (SDSS), we investigate the cosmological evolution of the Baldwin Effect, i
.e. the relation between the equivalent width (EW) of the civ emission line and continuum luminosity. We confirm the earlier result that there exists a strong correlation between the civ EW and the continuum luminosity, and we find that, up to $zapprox 5$, the slope of the Baldwin Effect seems to have no effect of cosmological evolution. A sub-sample of 13960 quasars with broad civ $lambda$1549 AA emission line from SDSS is used to explore the origin of the Baldwin Effect. We find that civ EW have a strong correlation with the mass of supermassive black hole (SMBH), and a weak correlation with the Eddington ratio, $lb/ledd$. This suggests that the SMBH mass is probably the primary drive for the Baldwin Effect.
