It is the amount of electric charge per unit volume.

是电荷与体积的比值。

youdao

The Transpacific Stabilization Agreement bunker charge, a benchmark fuel surcharge imposed by shipping firms on sea freight, has risen from $455 per 40-foot equivalent unit in January 2007 to $1,130.

泛太平洋运价稳定协议组织的燃油附加费，一项船运公司在海上货物运输方面所使用的基准燃料额外收费，其每40英尺集装箱所相当的货物单位的费用已经从2007年1月的455美元上涨到1130美元。

youdao

The current is the charge flow per unit time .

电流是每单位时间流动的电荷。

youdao

The claim is that the telecoms companies charge us more per unit of data to send a text message next door than it costs to send a message to Mars.

FORBES: Insane Calculation: It Costs More To Send A Text Next Door Than To Mars

Because the number of potential customers for such experimental sensors is small, the firms manufacturing them have to charge a high price per unit just to cover the fixed costs of designing the product, setting up the factory, and so forth.

FORBES: High Sensor Costs Won't Stand in the Way of the Self-Driving Future

The way it might work is that the typical replicator will have patterns stored for common things, but the owners of something really special like Bass Ale will figure out a way to encrypt the structure so that they can charge you on a per unit basis.

FORBES: Must Earl Grey Collect Sales Tax From Captain Picard?