  The precessing jet-nozzle scenario previously proposed was applied to
model-fit the kinematics of five superluminal components (C19,C20,C21,B5 and
B7) of jet-B in blazar 3C345. Based on a specific pattern for the the
precessing common trajectory of jet-B, the kinematic properties (including
trajectory,coordinates, core separation and apparent velocity) were
model-fitted and their flux evolution could be studied. Through
model-simulation of their kinematic behavior, the bulk Lorentz factor, viewing
angle and Doppler factor were derived as continuous functions of time and the
association of their flux evolution with their Doppler-boosting effect was
investigated. The 43GHz light-curves of the five superluminal components can be
well interpreted in terms of their Doppler effect. The close association of
their flux evolution with the Doppler-boosting effect firmly validates our
precessing nozzle scenario and supports the traditional point-view that
superluminal components are physical entities (traveling shocks or plasmoids)
participating relativistic motion toward us at small angles. The
model-simulation of kinematic behavior of superluminal components by using our
precessing nozzle scenario with specific patterns (helical or ballistic)
assumed for the precessing common trajectories yields the model-derived bulk
Lorentz factor, apparent velocity, viewing angle and Doppler factor as
continuous functions of time, which are most applicable to study the connection
of flux evolution with Doppler boosting effect for the superluminal components.
