Study on the small-scale structures and material flows of solar quiescent filaments is very important for understanding the formation and equilibrium of solar filaments .
Using the high resolution H \alpha data observed by the New Vacuum Solar Telescope ( NVST ) , we present the structures of the barbs and the material flows along the threads across the spine in two quiescent filaments on 2013 September 29 and on 2012 November 2 , respectively .
During the evolution of the filament barb , several parallel tube-shaped structures formed and the width of the structures ranges from about 2.3 Mm to 3.3 Mm .
The parallel tube-shaped structures merged together accompanied with the material flows from the spine to the barb .
Moreover , the boundary between the barb and surrounding atmosphere is very neat .
The counter-streaming flows were not found to appear alternately in the adjacent threads of the filament .
However , the large-scale patchy counter-streaming flows are detected in the filament .
The flows in one patch of the filament have the same direction and the flows in the adjacent patch have opposite directions .
The patches of two opposite flows with a size of about ten arcseconds exhibited alternately along the spine of the filament .
The velocity of these material flows ranges from 5.6 km/s to 15.0 km/s .
The material flows along the threads of the filament did not change their direction for about two hours and fourteen minutes during the evolution of the filament .
Our results confirm that the large-scale counter-streaming flows with the certain width along the threads of the solar filaments exist and are well coaligned with the threads .