An evaluation system for the surface quality of magnesium alloy die castings was established based on an automobile cylinder head cover component.

建立了一套汽车发动机缸盖罩盖镁合金压铸件外观质量的评定系统。

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Closure cover system is one of important parts of landfill site construction, it includes landfill gas discharge guiding layer, geotechnical film, drainage layer and plant cover surface soil layer.

封场覆盖系统是垃圾卫生填埋场建设的重要组成部分，覆盖系统包括气体导排层、土工膜、排水层、植被表土层。

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