摘要
Fig.3(a)on page 488 and Fig.7(a,a′)on page 493:It has come to our attention that the SEM pictures of Fig.3(a)and Fig.7(a,a′)for the fractured and worn surfaces of pure EP,respectively,are misused,because they have been reported in our previous work and were chosen accidentally to denote as the same control sample prepared using the exactly same procedure.The corrected Fig.3(a)and Fig.7(a,a′)are shown below.The data analysis,descriptions and conclusions are not affected by these unintentional errors.
