2x2C∠ k=1 k=0.1 0.8 0.6 0.2 0.2 0.4 0.6 0.8 0.2 0.4 0.60.8 k=001 k=0.001 0.8 08 0.6 06 04 0.2 0.2 0.4 0.6 020.40.60.8