With the magnetic field turned on, the iron layers both magnetize, say, in the spin-up direction, so all of the spin-down electrons move through the entire sample without scattering.
加上磁场后，两个铁层都被磁化，假如是上方向，那么所有下自旋的电子移动通过整个样本都没有散射。
2
If a wide scattering vector range is needed, one has to measure the same sample under different instrument configurations.
若要获取较宽散射矢量范围的实验数据，还要改变实验仪器设置，对同一样品进行几次测量。
3
Because the scattering spectrum of nanoparticles is determined by nanoparticles size, so only part of the sample can be observed at single Angle in measuring nanoparticles size.