seal: n.〔sing., pl.〕【动物；动物学】1.海豹。2.海豹毛皮(制品)。3.海豹皮色〔灰黄深褐色〕。4.〔Seals〕〔美国〕海豹突击队〔美国的一支海陆空军突击队〕 the common [harbor] seal (斑纹)海豹。短语和例子the fur seal 腽肭兽，海狗。vi.猎海豹。n.1.(打在火漆，铅等上的)火漆封印；封蜡；封铅；封条。2.捺印；封缄。3.
As flow begins , the plates open in response to a resultant force ( f ) which acts as the center of the sealed surface area 当流体开始流动时，阀瓣在作用在密封表面中心的合力( f )作用下开启。
