SPF is a nonlinear scale of how much UVB radiation is needed to give protected skin a sunburn.

SPF是一种非线性的比例，关于的是造成晒伤的b波紫外线的量。

And this is usually represented by the nonlinear decibel scale, where a normal conversation is around 60 decibels and a rock concert is around 120 decibels.

这通常由非线性分贝标度表示，其中正常的对话约为 60 分贝，摇滚音乐会约为 120 分贝。