南京直立人
Homo erectus from Nanjing
nanjing ape man
半圆顶直立堤
semi-circular erected mixture breakwater
半圆顶直立混合堤
semi-circular erected mixture breakwaters
半直立水工护岸
half-vertical hydraulic revetment
长期直立
Long-term upright posture
单旋翼涵道风扇式无人直升机
single rotor autonomous helicopter with ducted fan