B IOA 2 2 g pg 2 (18++)-(=28+ 12十 2 f 2 2 (=1g+p+p1)-(二2p+ 2 p+n2)=4phf he g p g u z g p g u z + + − + + ) = − 2 ) ( 2 ( 2 2 2 2 1 2 1 1   wf we u p z g u p z g + + − + + ) = − 2 ) ( 2 ( 2 2 2 2 1 2 1 1   p p h g u p z g u z g +  + −  +  + ) =  f − e  2 ) ( 2 ( 2 2 2 1 2 2 1 1