Efficiency is crucial in such cells if they are ever to be a substitute for existing methods of mass power-generation, such as coal and gas.

对于这些太阳能电池来说，要想取代现有的大规模发电方法，如煤炭和天然气，最关键的是效率。

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A useful unit converter can help you make the daily calculation, including conversion of area, density, energy, force, length, mass, power, pressure, speed, temperature and volume.

一个有用的单位转换器可以帮助您日常计算，包括面积，密度，能源，力，长度，质量，功率，压力，速度，温度和体积的转换。

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"This man actually said in February 2003, Tony Blair addressed the house and said that Saddam can stay in power if he hands over his weapons of mass destruction,".

VOA: standard.2009.12.13

That quantity in parenthesis, I have a mass which is a positive number. Something raised Something raised to the fourth power has got to be positive.

顺便说一句,质量这个量是个正数,四次方的值,肯定是正数。

麻省理工公开课 - 固态化学导论课程节选

As momentum changers go, I think we can all agree the 30 minute mass power outage now goes to the head of the class.

FORBES: Connect

By combining data from the two steps an equation linking mechanical power (dependent on mass) to electrical power (calculated by multiplying voltage by current) can be derived.

ECONOMIST: Weighing a kilogram

Along with millions of other out-of-date and unsecured PCs strung together by the Internet--what Corman calls "the leper colony"--those machines represent a combined mass of computing power responsible for most of the Net's spam e-mails, much of its click fraud, and the vicious "denial of service" attacks that can knock sites offline and even destroy online businesses altogether.

FORBES: Zombie Storm Rising