After K_(1C) reaches to a maximum value, i. e. about 25 MPam~(1/2) (letP_Q = P_(max)), it decreases.

• 实验表明:随着V_f的增加,K_(1C)增加,当V_f达到40%25左右时,K_(1C)达到最大值,尔后随V_f增加而降低。