注意到当0≤r≤1时1≤≤2 当1≤r≤2时r≤≤2 i=do dr -rdz+ dr-. rdzI =27(2-)+2j(2-c)m=2n2注意到 当0  r  1时 1  z  2 当1  r  2时 r  z  2 [ ] 2 1 2 2 0 1 0 2 1 rdz r e rdz dr r e I d dr r z z =  +          = − + − = 2 1 2 2 2 2 (e e) 2 (e e )dr 2 e r   