Section 3.4 S=1-ek)s (3.32) (a) (b) 0.8 0.8 -- 0.6 (k)=1.5 0.6 y s 0.4 (k)=1 0.4 0.2 个 0.2 (k〉=0.5 0 0.2 0.4 0.60.8 1 0 s (k) Section 3.4