Induction, magnetic

The principle physical phenomenon of applying the eddy current method for evaluating the amount of residual austenite in the structure of quenched steel is magnetic induction, involving the influence of the changeable magnetic field on the studied area, found under the probe. 

In Fig. 2a, we compare the modulus of the normal component of the magnetic induction B (r) provided by the sensor and the one calculated by the model. Because of the excitation s shape, the magnetic induction B° (r) is rotation invariant. So, we only represent the field along a radii. It s obvious that the sensor does not give only the normal component B = but probably provides a combination, may be linear, of... 

In Fig. 3a,b are shown respectively the modulus of the measured magnetic induction and the computed one. In Fig. 3c,d we compare the modulus and the Lissajous curves on a line j/ = 0. The results show a good agreement between simulated data and experimental data for the modulus. We can see a difference between the two curves in Fig. 3d this one can issue from the Born approximation. These results would be improved if we take into account the angle of inclination of the sensor. This work, which is one of our future developpements, makes necessary to calculate the radial component of the magnetic field due to the presence of flaw. This implies the calculation of a new Green s function. 

Magnetic fluids Magnetic flux leakagf Magnetic inductions Magnetic level indicator Magnetic materials... 

Table 1. Magnetic Induction Required to Extract Discrete Minerals...

Magnetic flux density (magnetic induction) gauss G, Gs 10-4T... 

Derivation of this equation is actually far from straightforward. In electromagnetism, we describe static fields by the electric field E and the magnetic induction B. For our purposes, we need to enquire about the potentials rather than the fields, and these are defined by... 

In the case of a uniform magnetic induction along the z-axis, B = you will find that the vector field... 

The derivations given above related to a single particle in a constant magnetic induction. For a molecule within the Bom-Oppenheimer approximation, the derivation is similar except that we take the nuclei to be fixed in space. There is a nuclear and an electronic contribution to each property. 

In the presence of an external magnetic induction B this dipole Pm has a potential energy given by the laws of classical electromagnetism as... 

All possible alignments between the dipole and the magnetic induction are allowed, and the energies are continuous there is no hint of quantization. 

Atomic and molecular magnetic dipoles have to obey the angular momentum laws of quantum mechanics, since they are proportional to angular momenta. Each dipole can therefore make just a number of orientations with an applied magnetic induction B. Each allowed orientation corresponds to a different potential energy, and absorption of a photon with suitable energy may cause a change in orientation. 

The simplest place to start is with a hydrogen atom. The experimental ESR spectrum shows two lines separated by 1420.4 MHz (often reported as a magnetic induction, since transitions occur at the resonance condition hv = In... 

To illustrate the use of the vector operators described in the previous section, consider the equations of Maxwell. In a vacuum they provide the basic description of an electromagnetic field in terms of the vector quantifies the electric field and 9C the magnetic field The definition of the field in a dielectric medium requires the introduction of two additional quantities, the electric displacement SH and the magnetic induction. The macroscopic electromagnetic properties of the medium are then determined by Maxwell s equations, viz. 

The subscripts refer to Cartesian coordinates in the laboratory coordinate system. The terms E(go) and B(go) are the electric and magnetic induction fields, respectively. In addition, the nonlinear induced magnetic moment (magnetization) is defined as ... 

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