????:1????????:???????????

2??????????

3?????????

4??????????

5????????

????? ? | ??????? ????????????????

??????????????????,“????,??”“?????,???”????

????????,?????????,??

?????????????

??????,???

???????????

???????????????????,??,??????????,???,??????

???????????D,????,??

??????,???????D???????????,???????????D??????

?????

????????,??????????

?????

1.??????

?????:?????????????,?????????????????????????,??1000~1200????????????????,????????????????

??????D:???????????????D??,???(??????????20????????????)??????????????????D????????(????????????????)?????

??????:?,???????,??????????????????????????,??,???????????????

2.???????????????

???:?????????????????????????,?,??????????,??????????????,???,?????

?????????:?????????,?????????,???,??

??:????????????????????,?????????,?????????,????????????

???????

?????????

??

?????????,?????X?????????????(DXA)????X?????????????,??????????????????T?????????????????????=-2.5,?????????????????????

??

????

????????

??,???????????????,???????????????,???????????????,???,?????

??????????:??+????,?????????????????

?:?????????????????,?????????,????????,?????????????????????,????

????????????:??????????? ????

????????:?????