It can be seen from Figure 12b that the diameter of the stretched fiber becomes smaller and the longitudinal grooves are deepened. This is because the fiber has a larger orientation in the longitudinal direction after being stretched.
From Figure 12b, it can be seen that the fiber diameter after stretching becomes smaller and the vertical groove deepens, because the fiber has a larger orientation along the vertical after stretching.
It can be seen from Fig. 12b that the diameter of the drawn fiber is smaller and the longitudinal groove is deepened, which is because the fiber has a larger longitudinal orientation after stretching.