?下死点

... lower categories ==> 低级分类单位 lower center ==> 下死点 lower chain ==> 下链条 ...

?下止点

下止点 (ldp) lower dead point; bottom center; bottom dead point; ldc lower dead center; lower center; lower dead center(bottom dead center); lower dead point 止点规 dead center gauge .

?低级中枢

... 次级中子 secondary neutron; subsequent neutron 低级中枢 lower center 多级中断 multilevel interrupt ...