1. Four new types of organic siloxane surfactants with quaternary ammonium group have been obtained. 通过多步骤合成了四种含有季铵基的有机硅表面活性剂。
2. A great many proteins, especially enzymes, are oligomeric and consequently possess quaternary structure. 很多蛋白质尤其是酶类，是低聚物，因此拥有四级结构。
3. The natural thermoluminescence in Quaternary sediment has stored accumulated irradiated dose since the sediment deposited. 第四纪沉积物的天然热释光中储存有自沉积以来的累积辐射剂量。
英英解释
n.
1. last 2 million years
2. the cardinal number that is the sum of three and one adj.
1. consisting of or especially arranged in sets of four
2. coming next after the third and just before the fifth in position or time or degree or magnitude
