The pectinate quills of the porcupine are barbed 豪猪栉状的刺是会刺人的。
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Whales use their pectinate teeth to gather plankton 鲸鱼用?们栉齿状的牙齿来捉浮游生物。
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The article analyze the concrete drying shrinkage mechanism , find the major factors of affecting the drying shrinkage , analyze the lack of shrinkage reducing agent , who be of low molecular weight and line chain , design a new shrinkage reducing agent ? ? shrinkage reducing agent of poly - acrylate . the shrinkage reducing agent of poly - acrylate is mainly composed of crylic acid 、 cinnamene 、 poly - glycol 、 solicitating agent 、 chain transferring agent and activator , which come by these processes of polymerization 、 esterifing and neutralization to form a pectinate polymer , which have a high molecular weight and many poly - oxidative alkenes 论文分析了混凝土干燥收缩的机理,确定了影响干燥收缩的关键因素,分析已有低分子量的、直链型减缩剂的不足,设计了一种新型的减缩剂? ?聚丙烯酸盐类减缩剂,其主要由丙烯酸、苯乙烯、聚乙二醇、引发剂、链转移剂、催化剂等经过聚合、酯化和中和反应,生成一种高分子量的、含聚氧化烯链的聚合物。
