超音波法液位元元元元元元测定
ultra-sonic method of liquid meaduremert
方向线素特征
directional line element feature
生命元素特征
benefical or harmful element
特征元素约束
restriction of characteristic element
微量元素特征
micro-element characteristics
trace elements characteristics
trace element
trace elements
岩、矿石微量元素特征
microelement of rock and ore
Pb-Sr-Nd同位素特征
Pb-Sr-Nd isotopic characters
S—N曲线特征
S—N curve characteristics