【计】 最小二乘方拟合

自行研制了流体导热系数的测量装置，采用锁相放大器获取3ω电压与频率的关系，并借助最小二乘法，算出待测试样的导热系数。

last but not least

(not) in the least/the least bit

least square method

nonlinear iterative partial least square

least square straight-line fit

to say the least

Least absolute shrinkage and selection operator，LASSO

least significant byte