超声波在介质中传播时，遇到不同的声阻 界面（Z,、尽）时

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SQL Error: select id,body,options from ***_enewstiku where sourceid='31793' and id < 2541750 and id<>'2541750' order by id desc limit 5 SQL Error: select id,body,options from ***_enewstiku where sourceid='31793' and id > 2541750 and id<>'2541750' order by id asc limit 5