It should be homogeneous in structure , with smooth surface , without the crack , airbubble , flatted , mechanical damage scratch , knife mark and so on .

质地均匀、外观平整、表面光滑，无裂纹、气泡、分层，没有影响使用的机械损伤、刀痕等缺陷。

On this basis , the main reason why surfactants can intensify the boiling heat transfer of water , glycol-water was studied : the additive introduced increases airbubble separation frequency of pure components and mixture and decreases the separation diameter .

在此基础上，本文讨论了表面活性物质强化水、乙二醇-水溶液沸腾传热的主要原因是添加剂的加入导致了纯组分及混合物气泡脱离频率增加，脱离直径变小；