When draw down ratio was greater than 1, the dope thread in the air gap was axially drawn with the rising of orientation degree so the fiber tenacity was strengthened.

• 在喷头拉伸比大于1的情况下，原液细流在空气层中得到轴向拉伸，加大了初生纤维的取向度，所以纤维强度得到加强。