The near-axis field distribution of circular aperture antennas is obtained by numeric integration method.

采用数值积分方法分析了圆口径天线非轴向近场分布特性。

youdao

And, if you take a vector field where maybe everything is rotating, a flow that's just rotating about some axis, then you'll find that its divergence is zero.

如果取一个有旋的向量场，流体流动方向是环绕某个坐标轴的，那么就会发现它的散度是零。

youdao

When an electric field is applied to the electrodes the piezoelectric material translates this into a mechanical strain along its radial axis, causing it to vibrate.

当两个电极之间形成电场时，压电性物质便将电场转化为沿径向轴的机械压力，使纤维震动。

youdao

The Geomagnetic pole is the north end of the axis of the geomagnetic field which surrounds the Earth and extends into space as the magnetosphere.

BBC: NEWS | UK | British man scores polar success

In particular, every electron has its own magnetic field aligned with the axis of its spin.

ECONOMIST: How to record a memory on a wire

The reaction would also be carried out in a differently shaped apparatus not a torus, but a cylinder with a magnetic field running along its axis.

ECONOMIST: How to get an energy rush without doughnuts