Effect Of Magnetostatic Field Research Articles

Effect of Magnetostatic Field on Microstructure of 7075 Aluminum Alloy Strip Manufactured by Twin-Roll Casting

In this paper, the effect of magnetostatic field on the microstructure and microsegregation of 7075 aluminum alloy strip by twin-roll casting is researched , and the result shows that when no electromagnetic field is applied during the process of roll-casting , the microstructure of 7075 strip is most composed of coarse columnar and dendritic crystal , the direction of grains is equal to roll-casting direction. When the magnetostatic field with 0.13T intensity is applied during the twin-roll casting, the microstructural of strip becomes uniform ,refined and equiaxed at the central zone of strip, and the dendritic crystal at the surficial is disordered and refined significantly.

Effect of Magnetostatic Field on Microstructure of 5005 Aluminum Alloy Sheet by Roll-Casting

The roll-casting technology of 5000 series aluminum alloy is one of the difficulties at present. Roll-casting technology was employed in this paper and high quality 5005 aluminum alloy sheets were fabricated successfully under different conditions. The solidification of melt in roll-casting process is the rapid directional solidification. The effect of magnetostatic field on microstructure of 5005 aluminum alloy sheet by roll-casting has been investigated and analyzed. The results indicate that imposing magnetostatic field can refine the grains of 5005 aluminum alloy.

Testing nonlinear electrodynamics in waveguides: the effect of magnetostatic fields on the transmitted power

In Born–Infeld theory and other nonlinear electrodynamics, the presence of a magnetostatic field modifies the dispersion relation and the energy velocity of waves propagating in a hollow waveguide. As a consequence, the transmitted power along a waveguide suffers slight changes when a magnetostatic field is switched on and off. This tiny effect could be better tested by operating the waveguide at a frequency close to the cutoff frequency.

Effect of magnetostatic field on the microstructure of magnesium alloy

Magnesium alloy is a light alloy material with potential applications,but many problems need to be studied for it.In the experiment the process of solidification and the microstructure of magnesium alloy under the effect of magnetostatic field was studied.Some phenomena were found that the microstructures of magliesium alloy were changed obviously:the thickness of grain boundary was reduced，the content of solute in the grain was increased apparently and reduced slightly in the grain boundary.The analysis showed that urlder the effect of magnetostatic field the microstructure of magnesium alloy was improved，and this has great significance to improve the propenies of magnesium alloy.

Effect of magnetostatic field on the second-order optical susceptibility of III-V semiconductors

An analytical investigation of the application of a large magnetostatic field on the second-order optical susceptibility χ(2) in III-V semiconductors like GaAs and InSb is reported. The model is based upon the parity indefiniteness of the electron wave functions in crystals lacking inversion symmetry. The generalized force and the electronic dipole moment operators are accordingly taken to be 2×2 matrices with all elements being finite. We have followed perturbation technique for the density matrix. The magnetostatic field renormalizes the transition frequency and sharpens the density of states. Both the resonant as well as nonresonant three-wave parametric interactions have been discussed. Numerical estimates made for InSb crystal under resonant regime reveal considerable enhancement in the real part of χ(2) even at moderately low magnetic field while the imaginary part exhibits a near saturation behavior. Under nonresonant laser excitation, both χ(2)r and χ(2)i rise very sharply with magnetic field for effective cyclotron frequency ωc≤ω0−ωg, ω0 and ωg being the pump and crystal band-gap frequencies, respectively. Quite interestingly, χ(2)r and χ(2)i decay almost exponentially to very low values at ωc>2(ω0−ωg).

Effect of Magnetostatic Field on the Stimulated Raman Scattering of Transversely Polarized Electromagnetic Waves and Raman Instability in Semiconductor Plasmas

AbstractThe stimulated Raman scattering of a large amplitude transversely polarized electromagnetic pump wave from both, the electron plasma wave and the molecular vibrations produced at a frequency equal to that of transverse optical phonon, is investigated in an n‐type semiconductor plasma. The general dispersion relation is obtained considering only the Stokes' component of the scattered electromagnetic wave in the presence of a large magnetostatic field applied at an arbitrary angle to the direction of propagation of the pump wave. The analysis is applied to both the cases of isotropic (B0 = 0) and magnetoactive (B0 ± 0) plasmas. The threshold electric field necessary for the onset of Raman instability and the growth rate of the unstable mode well above the threshold is studied. It is concluded that the threshold pump amplitude as well as the growth rate have strong dependence on the orientation of the magnetostatic field with respect to the wave vectors k, k1 and its magnitude.