对层状晶体，由于振动的膜效应，使得沿平面层方向的格林乃森参量在某些温度范围内出现负值，而一般晶体的格林乃森参量总为正值。

Second, for layer crystals the Grüneisen parameter along the plane may be negative for some temperatures because of vibration film effects, but for other crystals is positive always.

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现在街道都铺上了路砖，除了散发着锯木芳香的锯木厂发出的呜呜声之外，佩森城乃一片静谧。

Now streets paved. Payson lay quiet but for the whine of sawmills releasing the sweet scent of cut timber.

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