US  8,114,570  B2  Sheet  4 of 4  Feb.14,2012  U.S.  Patent  7.999  7.979  7.957  7.775  ~Jul  7.768  7.761  7.753  o:,  7.740  7.736  7.728  7.722  7.717  7.713  7.705  7.698  7.687  7.682  7.680  7.676  7.673  7.668  7.657  7.650  7.645  7.630  7.445  7.439  7.424  7.402  7.268  4.804~  4.768,\  4.760~  t~~~:::7,r,---==  4.104J!e  4.697  4.661  4.569  4.533  4.527  4.506  4.491  4.470  4.462  4.427  a,  2.828~  2.812~  2. 797  ~  2.619--..,_  2.592~  2.563--- 2.317-....  2.293--=:::- 2.152~  2.125~- /=I\)  2.084.....,,..1,1  2.048  t911’i  1.1207  1.326  ~  l:~~!~i  1.227-r  1.143  1.122  0.934  0.912  0.000  "ti  0.011:l  -0.011  "ti  0  S  15.865  2.000  2.020  1.988  1.932  ~  4.070  0.115  FIG.4 