恒定的英文：
invariablenes

For instance I can instantly know the constant distance.
例如我可以即刻知道该恒定间隔。

The glomerular filtration rate remains relatively constant
肾小球滤过率也能保持恒定。

The constancy of the speed of light seems, at first thought, unremarkable
光速恒定，初看起来好像很平常。

This is a constant-amplitude wave which is essentially the same on the conjugate image plane
这是一个振幅恒定的波，在共轭的象平面上也是如此。

unsteady flow in open channel
明渠非恒定流

The entropy density is constant ahead of the shock.
冲击波前方的熵密度是恒定的。

congestion of the mucosa is a variable sign
粘膜充血是不恒定的表现。

Doing a steady 4000 revs(per minute)
达到(每分钟)4000转的恒定转速.

In undisturbed inertial motion, the angular momentum is constant
在无扰动惯性运动中，角动量是恒定的。

We may take the form of a thermostatically controlled housing temperature
我们可以采取恒定控制罩温的形式。