magnetic variation 磁偏角 ; 磁变 ; [地物] 磁差 ; [物] 磁性变化
abnormal magnetic variation 异常磁变 ; 磁差异常 ; [地物] 异常地磁变化
annual magnetic variation 周年磁变 ; 年磁变 ; 磁周年差 ; [地物] 年磁差
magnetic diurnal variation [地物] 磁周日变化 ; 地磁日变 ; 月日磁变 ; 地磁日变化
annual change of magnetic variation 磁变年差 ; 磁差年变化
magnetic variation chart 磁偏差海图 ; 磁经偏差图
magnetic annual variation [地物] 磁周年差 ; 磁年差
transient magnetic variation 瞬磁变 ; 瞬间磁变
Under the action of variation magnetic field, the permanent magnet moving-coil drives the plunger pump to move up and down and lift oil up to ground.
通过动力电缆给井下直线电机供电后产生交变磁场，永磁体动子在交变磁场作用下带动泵柱塞上下往复运动，从而达到举升抽油的目的。
The regular variation of crystallization temperature, magnetic ordering temperature and average hyperfine magnetic field of the amorphous alloys with Nb content were observed.
观察到非晶合金的晶化温度，磁有序温度和平均磁超精细场有规律性的变化。
The results show that the non-linearity is mainly attributed to a thermal fluctuation magnetic after effect and a numerical variation of the magnetic domain with frequency.
结果表明，非线性主要来源于热起伏磁后效和为了降低微涡流损耗而引起的磁畴数随频率的变化。
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