Bubble wrap encapsulated - air plastic sheeting ( bubble wrap ) is packing material made of air bubbles that are encased between two poly sheets as they are sealed together 压缩空气塑料薄膜（泡沫包装）是一种包装材料，它由两块聚酯薄膜密封在一起而在它们之间装入的气泡制成。
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But such research is very limited and has not been investigated in domestic at the present time . the purpose of this project is to satisfy this requirement and establish the base for farther research 目前国内关于液相端面开螺旋槽的机械密封研究工作非常有限，本课题论文目的就是通过探讨端面间薄膜密封的机理和密封性能，从而为进一步的研究奠定基础。
