How did you think of the combination of this material of parchment paper and the two pens in the early?
2
封口材料中聚乙烯膜和塑料瓶盖两个处理玻璃化率相似且玻璃化率高,硫酸纸次之,棉塞的最低。
The vitrification rate caused by cotton plug wrapped in cheese cloth was the lowest among all seal materials, including polyethylene film, plastic cover and sulfuric paper.