很少有美白牙膏经过任何形式的临床试验，有些美白牙膏摩擦剂含量过多，会伤害你的牙齿或让你的牙齿变得过分敏感。
Very few whitening toothpastes have undergone any type of clinical trial, and ones that are too abrasive can damage teeth or make them very sensitive.
胶合、咬死现象是高速、重载滑动摩擦副常见失效形式之一。
Scuffing appears mainly in sliding contacts under high speed-heavy load conditions.
运用摩擦学原理提出了轮胎磨损的分类形式，为正确预测正常工作条件下的轮胎磨损率提供了必要的基础知识。
The wear classifications are presented based on the principle of Tribology, which provide the fundamental knowledge for correctly predicting tire wear rate at normal service conditions.
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