Rare earth metals, such as metallic neodymium and metallic didymium (metallic praseodymium-neodymium), are used for rare earth magnets, mainly neodymium-iron-boron magnet.

稀土金属，如金属钕和金属皮（金属镨，钕） ，用于稀土，主钕。

Evolving process of hub dynamo which used in bicycle is presented. The performance of magnetite viz. ferrimagnetism or NdFeB is analyzed. The prospect of marketing is viewed.

绍了自行车上使用的花鼓式发电机的演变过程，分析了所用石，即氧体或钕的性能优劣，并进行了市场前景展望。