Obsidian is a kind of black glass formed when the heat of a volcano melts the silica material in sand.

VOA: special.2009.09.16

So that would probably be de Broglie's answer for why, in fact, we're not observing the wavelength behavior of material on a day-to-day life.

所以那就可能是德布罗意关于,为什么我们无法再日常生活中,观测到物质的波动行为的答案。

麻省理工公开课 - 化学原理课程节选

I--You're just off on a different planet in terms of your capacity to process aural material, but we--I can't do that.

我,大家其实到了另外一个星球,要说咱们对声音材料的处理能力,但是我们,我无法做到那样

耶鲁公开课 - 聆听音乐课程节选

This property would be desirable in a material for making helmets, says Mr Mahdavi.

ECONOMIST: MONITOR

And even just understanding the atomic-scale defects in a material can suggest better ways of making it.

ECONOMIST: Small wonders

In a material sense, even manual laborers are phenomenally wealthy by historical standards.

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