  Streaming instability is hypothesized to be triggered at particular
protoplanetary disk locations where the volume density of the solid particles
is enriched comparable to that of the gas. A ring of planetesimals thus forms
when this condition is fulfilled locally. These planetesimals collide with each
other and accrete inward drifting pebbles from the outer disk to further
increase masses. We investigate the growth of the planetesimals that form in a
ring-belt at various disk radii. Their initial mass distributions are
calculated based on the formula summarized from the streaming instability
simulations. We simulate the subsequent dynamical evolution of the
planetesimals with a protoplanetary disk model based either on the minimum mass
solar nebula (MMSN) or on the Toomre stability criterion. For the MMSN model,
both pebble accretion and planetesimal accretion are efficient at a close-in
orbit of $0.3$ AU, resulting in the emergence of several super-Earth mass
planets after $1$ Myr. For comparison, only the most massive planetesimals
undergo substantial mass growth when they are born at $r{=}3$ AU, while the
planetesimals at $r{=}30$ AU experience little or no growth. On the other hand,
in the denser Toomre disk, the most massive forming planets can reach Earth
mass at $t{=}1$ Myr and reach a mass between that of Neptune and that of Saturn
within $3$ Myr at $30$ AU and $100$ AU. Both the pebble and planetesimal
accretion rate decrease with disk radial distance. Nevertheless, planetesimal
accretion is less pronounced than pebble accretion at more distant disk
regions. Taken together, the planets acquire higher masses when the disk has a
higher gas density, a higher pebble flux, and/or a lower Stokes number of
pebbles.
