magnetic field gradient短语¹⁴⁴⁹⁷²⁺² 基本例句 磁场梯度 As an example, magnetic field gradient of16-pieces quasi-segmented, trapezoidal quadrupole is calculated and compared with a16-pieces plane head segmented quadrupole. 试算了16体准形四极透镜的梯度，并同相应的16体平头扇形四极作了比较。 cnki