A proton contains three charged quarks bound by the strong force and its radius is defined as the distance at which the charge density drops below a certain value.

一个质子由三个带电的夸克通过强相互作用力结合而形成，它的半径是由电荷密度降到某一确定值的距离来确定的。

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Field data were analyzed. It showed that axis force increased along with pipe jacking at the very start, and it maintained stated basically when jacking to a certain distance.

实测数据分析表明，管节开始顶进时轴力随顶进距离增大而增大，顶进到一定距离后，基本维持在一定范围内。

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From a man who is one of the most peaceable presences I've lately encountered, a gentle giant of a mind, this car is nothing but a weapon: a very large, very Norse, not-all-that-pretty ax meant to be thrown with staggering force at a great distance.

WSJ: 2012 Koenigsegg Agera R Review: A Blasting Horizontal Roller Coaster | Rumble Seat by Dan Neil

Experiments currently being undertaken at Stanford, and also by John Price, a physicist at the University of Colorado, will measure the force of gravity over a distance of less than a millimetre (the size of loop expected if there are only two extra gravity-swallowing dimensions).

ECONOMIST: A matter of gravity

Raytheon, known more often than not in these parts for its ability to zap people at a distance with microwaves, has just announced a little something called One Force Tracker.

ENGADGET: Raytheon's iPhone app will track enemy combatants in real time