Kuo discovered that compasses do not point true north but to the magnetic North Pole. This was a decisive step to make them useful for navigation.
沈括发现，指南针并不是真正的指向北方，而是指向地磁的北极，这对指南针用于导航走出了决定性的一步。
The self-holding of a motor pole and the magnet rotor of the step motor can ensure the stable working situation, which reduces the energy consumption of the valve.
工作状态切换后可以停止通电，电机磁极与步进电机磁转子自保持可保证工作状态稳定，降低了阀自身的能耗。
The step through test and independent activity were used to observe effect of uneven constant magnetic field pole N and S on learning and memory impairment induced by hypobaric hypoxia .
用避暗实验法和自主活动法，分别观察了非均匀恒磁场N极、S极对急性低压缺氧引起的学习记忆障碍的影响。
The step through test and independent activity were used to observe effect of uneven constant magnetic field pole N and S on learning and memory impairment induced by hypobaric hypoxia .
用避暗实验法和自主活动法，分别观察了非均匀恒磁场N极、S极对急性低压缺氧引起的学习记忆障碍的影响。
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