Double channel ditch (W-type ditch)
weeper drain;weep drain;drainage ditch;drain ditch
18-Crown-6
18-冠-6
18冠6
18-冠醚-6
18–冠<醚>–6
18-Crown-6-tetracarboxylic
18-Crown-6-tetracarboxylic acid
3’ -allylbenzo-15-crown-5
4’-bis 4-hydroxyphenylazo dibenzo-14-crown-4
4’-bis 4-hydroxyphenylazo dibenzo-18-crown-6
4′-substituted benzo-15-crown-5