当温度升高时，通过电动风门提供新鲜空气或转换到空气再循环模式。

Motorized air dampers are used to bring in fresh air or, in times of higher temperature, switch over to recirculation.

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地壳早期演化研究的主题是探讨早期大陆形成、生长和再循环的地质过程及其地球化学和地球物理模式。

The topic of the study of the evolution of early crust is to probe into the processes of early continental formation, growth, and recycling, and their geochemical and geophysical models.

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