.1  ` & & MathType`Times New Roman-2 6)2 4(2 {)2 y(2 f)2 d(2 )2 (2  )2 (2 y)2 w( Times New Roman-2 ,22 q 32 1Times New Roman-2 t2 T2 gk2 t2 T2 t2 \T2 t2  M2  k2 = t2 T2 t2 QV2 Kk2 "T Times New Roman-2 {L2 L2 GT2 I2 LSymbol-2 G-2 2-2 2  +2 32 =Symbol-2 XmMT Extra-2 :& & "System-