The copolymer with star tail self-assembles into a tri-layer film structure and then the tri-layer structure evolves into a five-layer structure with the further increase of bulk packing fraction .

随着主体填充 分 率的增加， 星形共聚物会先自组装为三层结构，再过渡到五层结构。

With square facial-tissue boxes you can carefully open the bottom and put a roll of bathroom tissue in them with the tail sticking out and use it as facial tissue for a fraction of the cost .

对于外表平整的纸盒，你可以小心地打开底部，然后放入一卷卫生纸并将 尾部伸出，这样就做成了具有一定价值的 面纸。