工作原理：

      SHISHAIMIANSHANGDEWULIAOYIJIAOKUAIDESUDUXIANGPAILIAODUANYIDONG，WULIAOTONGSHIDEDAOSHAIFEN。YAODONGSHAIYUSHANGSHUJIZHONGSHAIZIXIANGBI，QISHENGCHANLVHESHAIFENXIAOLVDOUBIJIAOGAO。QIQUEDIANSHIDONGLIPINGHENGCHA。YIBANXUANKUANGCHANGHENSHAOYONGTA，ERBEIJIEGOUGENGHELIDEZHENDONGSHAIQUDAI。