设备茬市场上维持其价值的时期称为（ ）。

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SQL Error: select id,body,options from ***_enewstiku where sourceid='27079' and id < 2244469 and id<>'2244469' order by id desc limit 5 SQL Error: select id,body,options from ***_enewstiku where sourceid='27079' and id > 2244469 and id<>'2244469' order by id asc limit 5