density by volume

例句：

1. 1. The density of the material is crucial for its strength and durability.
   材料的密度对其强度和耐久性至关重要。
2. 2.The density of water in the ocean is much lower than that in freshwater.
   海洋中的水密度远低于淡水。
3. 3.The density of a substance can be determined using various techniques such as X-ray diffraction.
   通过X射线衍射等技术可以测定物质的密度。