〈美國〉=Petroleum Administration 石油管理局。
Pa =protactinium 【化學】鏷。
n. 名詞 〈口、兒〉爸〈papa 之略〉。

    1. Pa 6 for blow moulding

    2. The present work indicates the organic nf membranes and the inorganic nf membranes all have shortages, so develop composite nf membranes that have low cost, mechanically strong and thermally / chemically - resistant, easy to cleanout and good performances is a very important task. in this paper, the preparation of inorganic - organic composite nf membranes were presented. this composite comprise a porous sio2 / al2o3 support substrate, the pore diameters of which ranging from 10 to 15 nm, this inorganic support substrate having a polymer membrane which comprises an polyvinyl alcohol ( pva ) or polyamide ( pa ) densely deposited on at least one of the face surfaces thereof, the structural porosity of such pva and pa membrane ranging from 3 to 5 nm

      本論文以開發無機?有機復合納濾膜為出發點,首先在al _ 2o _ 3多孔微濾膜上利用溶膠?凝膠法制備sio _ 2 al _ 2o _ 3無機復合超濾膜作為無機?有機復合納濾膜的基膜;選用聚乙烯醇和聚酰胺為表面功能層材料,分別探討了以羥基丁二酸和磺基水楊酸為混合交聯劑,採用浸塗法制備了聚乙烯醇sio _ 2 ? al _ 2o _ 3復合納濾膜;以均苯二甲酰氯、哌嗪和二胺為單體,採用界面聚合法制備了聚酰胺sio _ 2 ? al _ 2o _ 3復合納濾膜,並對影響膜性能的諸多因素進行系統研究。
    3. It ' s almost 9 years since dong - goo ' s pa left home

    4. "i know what i'm saying, lonnie, " hatty insisted. "your pa's been gone a heap too long. "

    5. " i know what i ' m saying, lonnie, " hatty insisted. " your pa ' s been gone a heap too long.

      「我可不是瞎說的,朗尼, 」哈帶堅持說。 「你阿爸去得太久了。 」