附面层

boundary layer

face / side / surface / aspect / top / classifier for objects with flat surfaces such as drums, mirrors, flags etc

variant of 麵|面[mian4]

flour / noodles / (of food) soft (not crunchy) / (slang) (of a person) ineffectual / spineless

to pile on top of one another / layer; stratum / floor (of a building); story / (math.) sheaf / classifier for layers

variant of 附[fu4]

to add / to attach / to be close to / to be attached