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.

摘要介绍了自行车上使用的花鼓式的演变过程，分析了所用石，即铁氧体或钕铁硼的劣，并进行了市场前景展望。

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） ，用于稀土铁，主要钕铁硼铁。