“permeability(symbol: μ; unit: henry per metre)”的概念、定义、翻译、参考文献-科学参考

permeability(symbol: μ; unit: henry per metre)

Electronics and Electrical Engineering

The ratio of the magnetic flux density, B, in a medium to the external magnetic field strength, H, i.e.
$μ = \frac{B}{H}$
The permeability of free space is designated μ₀ and is termed the magnetic constant. In the system of SI units it has the value 4π ×10^–7 henry/metre. In other systems, such as the CGS and MKS systems, it has been given different values. Using Maxwell’s equations it can be shown that
$μ_{0} ε_{0} = \frac{1}{c^{2}}$
where ε₀ is the permittivity of free space and c is the speed of light.
The relative permeability, μ_r, is the ratio of the magnetic flux density in a medium to the magnetic flux density in free space for the same value of external magnetic field strength, i.e.
$μ_{r} = \frac{μ}{μ_{0}}$
For most materials μ_r is a constant. Diamagnetic materials have a value of μ_r less than unity. Paramagnetic materials have a value just greater than unity (see diamagnetism; paramagnetism). Ferromagnetic materials have values of μ_r that are very much greater than unity and that depend on the magnetic flux density (see ferromagnetism; magnetic hysteresis).
The incremental permeability is the permeability measured when a small alternating magnetic field is superimposed on a large steady one.

单词	permeability(symbol: μ; unit: henry per metre)
释义	permeability(symbol: μ; unit: henry per metre) Electronics and Electrical Engineering The ratio of the magnetic flux density, B, in a medium to the external magnetic field strength, H, i.e. $μ = \frac{B}{H}$ The permeability of free space is designated μ₀ and is termed the magnetic constant. In the system of SI units it has the value 4π ×10^–7 henry/metre. In other systems, such as the CGS and MKS systems, it has been given different values. Using Maxwell’s equations it can be shown that $μ_{0} ε_{0} = \frac{1}{c^{2}}$ where ε₀ is the permittivity of free space and c is the speed of light. The relative permeability, μ_r, is the ratio of the magnetic flux density in a medium to the magnetic flux density in free space for the same value of external magnetic field strength, i.e. $μ_{r} = \frac{μ}{μ_{0}}$ For most materials μ_r is a constant. Diamagnetic materials have a value of μ_r less than unity. Paramagnetic materials have a value just greater than unity (see diamagnetism; paramagnetism). Ferromagnetic materials have values of μ_r that are very much greater than unity and that depend on the magnetic flux density (see ferromagnetism; magnetic hysteresis). The incremental permeability is the permeability measured when a small alternating magnetic field is superimposed on a large steady one.
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