By analyzing the volume mass-transfer coefficient, the optimal operating flow-ratio and packed density were obtained.

通过考察体积传质系数，确定了纤维液膜萃取分离器的最佳填充密度和最佳流量比。

youdao

Using on-line monitoring technology, effect of the nozzle diameters on, liquid volume mass transfer coefficient, and its axial distribution were studied.

运用动态监测技术，测定了喷嘴孔径对鼓泡床质量传递的影响以及鼓泡床体积传质系数随床高的分布。

youdao

Because these galaxies' mass is spread out over larger areas, they have far fewer stars per unit volume than do conventional galaxies.

因为这些星系的质量分布在更大的区域，它们每单位体积的恒星数量比传统星系要少得多。

youdao

You just need a few macroscopic variables that are very familiar to you, like the pressure, the temperature, the volume, the number of moles of each component, the mass of the system.

你只需要某些你非常熟悉的宏观变量,比如压强，温度，体积，每个组分的摩尔数，系统的质量。

麻省理工公开课 - 热力学与动力学课程节选

Ah, but density is mass over volume.

但密度是质量除以体积

耶鲁公开课 - 基础物理课程节选

It is a constant battle for engineers to tweak systems to get them to use up less volume and mass.

FORBES: Why Is Privatized Space Travel A Challenge?

All of these systems take up volume and mass.

FORBES: Why Is Privatized Space Travel A Challenge?

But accurately working out Mathilde's volume (necessary because density is the ratio of mass to volume) was harder.

ECONOMIST: Asteroids