magnetic density的用法和样例：
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.
这种自转变慢的速率，几乎每一颗无线电波霎都量得到，而理论指出，此速率和星体的磁场强度有关。 - 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.
本发明的保健牙刷克服了现有磁癖牙刷中的磁场强度不够，疗效不明显及刷毛的倒毛现象等缺点。
