This is the permittivity of free space.

这是自由空间数。

And that  all still equals the charge inside the Gaussian surface divided by the permittivity of free space.

这仍然等于高斯面内的荷除以真空数。

We also know the Coulomb constant equals the  inverse of the quantity four pi times the permittivity of free space.

我们还知道库仑数等于四π乘以真空数的倒数。

The permittivity distribution reconstructed by ECT and sound velocity distribution reconstructed by URT are processed by pixel-to-pixel thresholding fusion method.

通过像素阈值融合方法处理ECT重建的数分布URT重建的声速分布。

And that is equal to the change in electric flux over time, multiplied by the permittivity of free space constant.

这等于通量随时间的变化乘以自由空间数的数。

ECT can be used to reconstruct the permittivity distributions of the cross section, while UT is skilled to distinguish the boundaries of two-phase.

ECT可用于重建横截面的数分布, 而UT擅长区分两相的边界。

And so if we look at basic free space permittivity, so what we would have in the middle now is going to be just a vacuum.

因此， 如果我们看一下基本的自由空间数，那么我们现在中间的将只是一个真空。

You can take our energy density equation and substitute the magnetic field magnitude, B, with the electric field, times the square root of the permittivity constants.

您可以使用我们的能量密度方程，并用场数的平方根时间替换磁场的大小 B。

The electric flux which passes through a sphere which is  concentric to a positive point charge equals the charge of the positive point charge  divided by the permittivity of free space.

通过与正点荷同心的球面的通量等于正点荷的量除以自由空间的数。

This equation simplifies down to an equation with two constants, the permittivity of free space for electric fields, epsilon naught, and the permittivity of free space for magnetic fields, mu naught.

该方程简化了具有两个数的方程，场的自由空间数 epsilon 为零，磁场的自由空间数 mu。

I won't blame you if you don't remember, but the permittivity of free space is a constant of proportionally we've used before, that relates electric charge to the physical effect of electric fields.

如果你不提我不会怪你，但自由空间数是我们之前使用的相对论数，它将荷与场的理效应联系起来。

29. Question: What is the key factor to consider when choosing a PCB material for high - frequency applications in PCBA? Answer: Low dielectric constant and low dissipation factor to minimize signal loss.

29. 问题：为 PCBA 中的高频应用选择 PCB 材料时要考虑的关键因素是什么？答案：低数低耗散因数，可最大限度地减少信号损失。

Mathematically, this equation says that electric flux is the integral of the electric field over the area of the surface, which is equal to the enclosed charge, divided by the permittivity of free space.

在数上，这个方程表明通量是表面积上场的一个组成部分，它等于闭合荷除以自由空间的数。

And we get that the magnitude of the electric  field which surrounds and is caused by an infinitely large, thin plane of charges  equals surface charge density divided by the quantity two times permittivity of free space.

我们得出结论，由无限大薄充平面产生的场的大小等于面荷密度除以两倍自由空间数。