??????????--???????????????????????
???????????3?? ??????3?? ???3??6?? ????6??9?? ????6?? ????12?? ???1.2?? ???1.2?? ??????2??4??????????0.9??
?????????Ρ??????????δ?????????????
???÷???????????棬??????
???????????????????????????
??????????--???????????????????????
???????????1?????????1??????1-2???????2-3???????2???????12???????4??????4???????8????????????3???
?????????Ρ???????δ?????????????
???÷???????????棬??????
?????????????????????????????