magnetic density的用法和樣例：
例句
- The spin-down rate has been measured for almost every radio pulsar, and theory indicates that it depends on the strength of the star's magnetic field.
這種自轉變慢的速率，幾乎每一顆無線電波霎都量得到，而理論指出，此速率和星體的磁場強度有關。 - The number of permanent magnets is two or more than two, the two poles of each magnet are arranged staggeringly to produce the alternate magnetic field.
本發明的保健牙刷克服了現有磁癖牙刷中的磁場強度不夠，療效不明顯及刷毛的倒毛現象等缺點。
