H a 2

α = 0.5

α = 1

α = 2

0.5

1.35 × 10−6

8 × 10−7

1 × 10−5

1

1.3 × 10−5

2.3 × 10−6

1.4 × 10−4

2

1.5 × 10−4

9 × 10−5

1.55 × 10−3

4

1.7 × 10−3

2.5 × 10−3

9 × 10−3

10

3 × 10−2

8 × 10−2

0.22