When a planar shock wave is sweeping a density layer, the deformation of the density interface and the wave configurations can occur.

运动激波在密度间断层传播时，引起密度分界面的变形，相应激波形状发生改变。

youdao

This melt water has a relatively low density, so it accumulates in the top layer of the ocean.

BBC: Melt may explain Antarctica's sea ice expansion

Waratek will let an enterprise swap out the middle layer of its software stack without changing its applications and significantly increase the density in data centers.

FORBES: Lousy London Economy Good For A Data Center Density Enhancer

As we learned when the console was initially announced, the Wii U's "proprietary high-density optical discs" hold up to 25GB of data -- equivalent with that of Sony's single-layer Blu-ray format on the PlayStation 3, and much larger than the Xbox 360's dual-layer DVD format.

ENGADGET: Take a very, very close look at the round-edged Wii U proprietary discs