line of force

基本解释

A magnetic line of force is a closed line, that is, it forms a loop without end.
磁力线是一条封闭线，即，它形成一条没有尽头的圈。
blog.sina.com.cn
An electric line of force is also a closed line; it too forms a loop and returns on itself.
电力线也是一条封闭线；它形成一个圈，返回原处。
blog.sina.com.cn
After the uninterrupted magnetic line of force treatment, the Masurium tower already continuously 6 months successes controlled the depression condition.
经过不间断的磁力线治疗，玛塔已经连续6个月成功控制住了抑郁症病情。

You know, one famous tactic is--if you have an infantry force coming forward, you send tanks in it to break up the line of the infantry, so that you can defeat the infantry in that way.
最有名的战术是,如果有敌方步兵逼近,你把坦克派过去,破坏他们的步兵阵型,以这种策略对付步兵
耶鲁公开课 - 古希腊历史简介课程节选

Furthermore, under national labor law, China limits overtime to 36 hours per month, yet workers complain of production line demands that force workers to show up for double or triple those maximum limits.
FORBES: China's 'Generation X'
Sometimes a poem can consist of a single sentence, the impact of which builds and gathers force in anticipation of its final line.
ECONOMIST: The Irish poet's new collection is his best for years
Unlike consumer grade smart phones that yield low performance and high failure rates when force-fit into line of business applications, the CS40 is built on Windows Embedded Handheld technologies including the Windows Mobile 6.5 platform and is designed for mobile professionals who need versatile and reliable access and acquisition of information in real-time, at the point of work.
ENGADGET: Intermec CS40 walks the work / play tightrope, WinMo 6.5 threatens to knock it off

an imaginary line representing a field of force, such as an electric or magnetic field, such that the tangent at any point is the direction of the field vector at that point