有用功

一些热量可直接使用或产生有用功；

Some of the heat is used directly or produces useful work ;

这电路中30%的电流不在做有用功。

30 per cent of the current in the circuit is not doing useful work .

他有用功的习惯，而且精力异常充沛。

He is of a studious habit , and unusually energetic ;

抽水设备输入的有用功是决定水井出水量分配和产生能量转化，即引起水头下降的根本原因。

Work input to water pumping equipments is the main reason for water head lowering .

引擎将燃烧过程产生的热量转化为有用功，进而转动车轮带动车辆在路上行驶。

Engines transform heat released in combustion into useful work that ultimately turns the vehicle 's wheels propelling it down the road .

当系统完全处于热涨落的环境中时，布朗马达成为最基本的热机工作模型，它可以整合环境的热涨落，输出有用功。

When the system is completely in the environment of thermal fluctuations , the Brownian motor becomes the most basic heat engine model . The Brownian motor can integrate thermal fluctuations and do useful work .

讨论了纸浆纤维在盘磨机打浆时所受到的剪切特性，并由此推导出平均剪切系数与磨片平均间隙、有用功及磨片几何尺寸之间的关系。

In this paper , we discuss the cutting characteristics of fibers passing through two discs and deduce the relationship of average cutting coefficient with average gap clearance 、 net power 、 geometrical parameters of disc .

她攻读博士学位有多用功啊！

How hard she has been working for her ph.d.degree !

你是否能通过考试就看你有多用功了。

Whether you can pass the exam depends on how hard you work .

这要看你有多用功，是不是常练习！

B : It will depend on how hard you work , and how often you practice !

他是一个从未有过的用功的人。

He is so diligent a man as ever lived .

考试成绩明白显示了我有多麽不用功。

My test results brought home to me how little I had studied .

他们顽强地投入严酷的现代学校生活，很难想象有比他们更用功的学生。

It is hard to imagine students more fiercely devoted to the rigours of modern academia .

战略与国际研究中心表示，包括我们自己在内，我们用来移动事物的能量中，有约四分之三的能量没有产生有用功。

According to the Center for Strategic and International Studies , about three quarters of the energy we use to move things , including ourselves , accomplishes no useful work .