&G )T,P,nc al- T aT S P,nB,nc l94ir H T2 T2 17 17 B C c B C P n n T P n B P n n B T T n G T T , , , , , , } ] ( ) [ ] { ( ) [         T P nc P nB nC B T G T n , , , , { [ ( )] }     P nB nC T P nc B T G n T , , , , { [ ( )] }      T P nc B T H n 2 , , [ ( )]    c T P n nB H T 2 , , ( ) 1     2 T H  