tbef50 t ss fWM b h (b) c h x (a) b x h ch y p2 o ( S A)- p2 A fcm A cm f y f p2 p1 f chb f f o yp cm f S A xbcm AA h A ho ho 加荷面积 临界周界 A chc ch ho 360 )( 384 5 0 4 0 4 l IE lg IE lq w s k s k 15 1 wk fHz 2 . 1/ yu ff %15 5 yu 20 y 210 bbbbce AffA sys / ll c h c h stst fA c vr Nn stst fA V vww fth f 22 max ) 2 ( 2 f 22 max ) 2 ( f n f n f n AA A n 21 1 1 f n AA A n 21 2 2
