Flow refers to the amount of fluid flowing through the effective cross section of closed pipeline or open channel in unit time, also known as instantaneous flow. When the amount of fluid is expressed by volume, it is called volume flow, and when the amount of fluid is expressed by mass, it is called mass flow. The volume of fluid flowing through a section of a pipeline in unit time is called the volume flow of that section.
Introduction of monthly rent
Mobile cards have the lowest monthly rent, and the minimum amount is different for different brands. 58 yuan's mobile GSM minimum package and 28 yuan's mobile M-Zone minimum package have monthly rental cards, which have stopped now. Only second-hand cards are sold online, and the minimum package for mobile business hall is 18 yuan. Standards may be different in different regions. It is suggested to call local 65,438+00086 for manual consultation first.