When injecting gas into polymer melt in extrusion from a single orifice, it is indicated that gas-melt interface formed showed three kinds of shapes: ring, round-ring, and round.

• 气体经单个喷嘴进入挤出机中熔体时所形成的气熔界面其形态有环状、团环状和团状三种,最常见的是团状。