“magnetic moment”的概念、定义、翻译、参考文献-科学参考

magnetic moment

Physics

The ratio between the maximum torque (T_max) exerted on a magnet, current-carrying coil, or moving charge situated in a magnetic field and the strength of that field. It is thus a measure of the strength of a magnet or current-carrying coil. In the Sommerfeld approach this quantity (also called electromagnetic moment or magnetic area moment) is T_max/B. In the Kennelly approach the quantity (also called magnetic dipole moment) is T_max/H.

In the case of a magnet placed in a magnetic field of field strength H, the maximum torque T_max occurs when the axis of the magnet is perpendicular to the field. In the case of a coil of N turns and area A carrying a current I, the magnetic moment can be shown to be m=T/B=NIA or m=T/H=μ‎NIA. Magnetic moments are measured in SI units in A m².

An orbital electron has an orbital magnetic moment IA, where I is the equivalent current as the electron moves round its orbit. It is given by I=qω‎/2π‎, where q is the electronic charge and ω‎ is its angular velocity. The orbital magnetic moment is therefore IA=qω‎A/2π‎, where A is the orbital area. If the electron is spinning there is also a spin magnetic moment (see spin); atomic nuclei also have magnetic moments (see nuclear moment).

Chemistry

The ratio between the maximum torque (T_max) exerted on a magnet, current-carrying coil, or moving charge situated in a magnetic field and the strength of that field. It is thus a measure of the strength of a magnet or current-carrying coil. In the Sommerfeld approach this quantity (also called electromagnetic moment or magnetic area moment) is the ratio T_max/B. In the Kennelly approach the quantity (also called magnetic dipole moment) is T_max/H.
In the case of a magnet placed in a magnetic field of field strength H, the maximum torque T_max occurs when the axis of the magnet is perpendicular to the field. In the case of a coil of N turns and area A carrying a current I, the magnetic moment can be shown to be m = T/B = NIA or m = T/H= μ‎NIA. Magnetic moments are measured in A m².
An orbital electron has an orbital magnetic moment IA, where I is the equivalent current as the electron moves round its orbit. It is given by I = qω‎/2π‎, where q is the electronic charge and ω‎ is its angular velocity. The orbital magnetic moment is therefore IA = qω‎A/2π‎, where A is the orbital area. If the electron is spinning there is also a spin magnetic moment (see spin); atomic nuclei also have magnetic moments.

Electronics and Electrical Engineering

1. (magnetic dipole moment) (symbol: m; unit: ampere metre²) A measure of the strength of a magnet. When a magnet is placed in a homogeneous magnetic flux of magnetic flux density B it experiences a torque T such that
$T = m \times B$
where m is the magnetic moment. If the magnet is a small coil of area dA carrying a current I, then the magnetic moment m is equal to IdA.
2. (magnetic dipole moment) (symbol: p_m; unit: weber metre) The product of magnetic moment m and the permeability of free space, μ₀:
$p_{m} = μ_{0} m$
Historically magnets and small circulating currents were considered to be dipoles consisting of two equal and opposite magnetic poles, analogous to electric charges, separated by a distance r (the magnetic length). The magnetic dipole moment p_m was the product of the magnetic pole strength and the magnetic length; it was determined by the torque, T, experienced when the magnet was placed in a magnetic field H. Thus p_m was determined by the relation:
$T = p_{m} \times H$
Modern usage strongly favours the first definition, the second definition being very rarely used. Small magnets, however, are frequently referred to as dipoles, particularly on an atomic scale, and the magnetic moment m termed the magnetic dipole moment. In modern texts these terms are defined by the first definition above. The term ‘magnetic moment’ has been used wherever possible throughout this dictionary as defined in 1. above.

Geology and Earth Sciences

The measured total intensity of magnetization of a sample, irrespective of the volume or weight of the sample itself. It is measured in units of A·m².

单词	magnetic moment
释义	magnetic moment Physics The ratio between the maximum torque (T_max) exerted on a magnet, current-carrying coil, or moving charge situated in a magnetic field and the strength of that field. It is thus a measure of the strength of a magnet or current-carrying coil. In the Sommerfeld approach this quantity (also called electromagnetic moment or magnetic area moment) is T_max/B. In the Kennelly approach the quantity (also called magnetic dipole moment) is T_max/H. In the case of a magnet placed in a magnetic field of field strength H, the maximum torque T_max occurs when the axis of the magnet is perpendicular to the field. In the case of a coil of N turns and area A carrying a current I, the magnetic moment can be shown to be m=T/B=NIA or m=T/H=μ‎NIA. Magnetic moments are measured in SI units in A m². An orbital electron has an orbital magnetic moment IA, where I is the equivalent current as the electron moves round its orbit. It is given by I=qω‎/2π‎, where q is the electronic charge and ω‎ is its angular velocity. The orbital magnetic moment is therefore IA=qω‎A/2π‎, where A is the orbital area. If the electron is spinning there is also a spin magnetic moment (see spin); atomic nuclei also have magnetic moments (see nuclear moment). Chemistry The ratio between the maximum torque (T_max) exerted on a magnet, current-carrying coil, or moving charge situated in a magnetic field and the strength of that field. It is thus a measure of the strength of a magnet or current-carrying coil. In the Sommerfeld approach this quantity (also called electromagnetic moment or magnetic area moment) is the ratio T_max/B. In the Kennelly approach the quantity (also called magnetic dipole moment) is T_max/H. In the case of a magnet placed in a magnetic field of field strength H, the maximum torque T_max occurs when the axis of the magnet is perpendicular to the field. In the case of a coil of N turns and area A carrying a current I, the magnetic moment can be shown to be m = T/B = NIA or m = T/H= μ‎NIA. Magnetic moments are measured in A m². An orbital electron has an orbital magnetic moment IA, where I is the equivalent current as the electron moves round its orbit. It is given by I = qω‎/2π‎, where q is the electronic charge and ω‎ is its angular velocity. The orbital magnetic moment is therefore IA = qω‎A/2π‎, where A is the orbital area. If the electron is spinning there is also a spin magnetic moment (see spin); atomic nuclei also have magnetic moments. Electronics and Electrical Engineering 1. (magnetic dipole moment) (symbol: m; unit: ampere metre²) A measure of the strength of a magnet. When a magnet is placed in a homogeneous magnetic flux of magnetic flux density B it experiences a torque T such that $T = m \times B$ where m is the magnetic moment. If the magnet is a small coil of area dA carrying a current I, then the magnetic moment m is equal to IdA. 2. (magnetic dipole moment) (symbol: p_m; unit: weber metre) The product of magnetic moment m and the permeability of free space, μ₀: $p_{m} = μ_{0} m$ Historically magnets and small circulating currents were considered to be dipoles consisting of two equal and opposite magnetic poles, analogous to electric charges, separated by a distance r (the magnetic length). The magnetic dipole moment p_m was the product of the magnetic pole strength and the magnetic length; it was determined by the torque, T, experienced when the magnet was placed in a magnetic field H. Thus p_m was determined by the relation: $T = p_{m} \times H$ Modern usage strongly favours the first definition, the second definition being very rarely used. Small magnets, however, are frequently referred to as dipoles, particularly on an atomic scale, and the magnetic moment m termed the magnetic dipole moment. In modern texts these terms are defined by the first definition above. The term ‘magnetic moment’ has been used wherever possible throughout this dictionary as defined in 1. above. Geology and Earth Sciences The measured total intensity of magnetization of a sample, irrespective of the volume or weight of the sample itself. It is measured in units of A·m².
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