Prions are invisible to the immune system , yet tough enough to survive harsh solvents and extreme temperatures. 是免疫系统无法看见的，在苛刻的溶液里和极端温度下都能顽强地活下来。
The characteristic features of these bearings for extreme temperatures include large radial internal clearance and special cages and shields. 这种用于极端温度的轴承特征是径向内部游隙大及带特殊保持架和防尘罩。
