T (h1-a1)-(-b) (h2-a2)-(-b 2 b-(h1-a1) b-[-(h2-a2 1000 2 h,t b 6+ 2 +b-hb+h2-a2∫ 2)、单位长度电容为 2: 80 U1000 h, tb-a b+av a tb-h, bth 3)、电场分布为 E 1000 2兀E h,-a+ b b-h,+ 4)、电荷密度最大值一定位于小柱的内侧 =D,=E。E·n max h1 2丌 h1 2兀b-h1+ah1-a+b1 1 1 1 ( ) ( ) 2 2 2 1 1 max 0 x h a n x h a i r r r r D E n = - = - = - × - = = ×      p t s e þ ý ü î í ì + - + - + - + - Þ = · 2 2 2 2 1 1 1 1 ln 1000 2 0 b h a b a h a b h pe h b a t þ ý ü î í ì + - + - + - + - = = = · 2 2 2 2 1 1 1 1 ln 2 1000 0 b h a b a h a b h U h b a C t t pe 2)、单位长度电容为 3)、电场分布为 ( ) ln 1000 ( ) 2 2 2 2 2 1 1 1 1 1 1 2 2 1 1 0 r r r r b h a r h a b r r r E      - - + - + = - = pe t 4)、电荷密度最大值一定位于小柱的内侧 ) 1 1 ( 2 1 1 b h a h -a +b + - + = p t þ ý ü î í ì - - - - - - - - - - - - - + - - = = [ ( )] ( ) ( ) ln ( ) ( ) ( ) ln 2 1000 2 2 2 2 1 1 1 1 0 b h a h a b b h a h a b pe t j j