통합 검색 | Korea Science

Mohamed, Hany M.;Abdalla, Mahmoud A.;Mitkees, Abdelazez;Sabery, Waheed
- Journal of Magnetics
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- 제20권3호
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- pp.322-329
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- 2015
This paper presents a new overlapped coilgun configuration to launch medium weight projectiles. The proposed configuration consists of a two-stage coilgun with overlapped coil covers with spacing between them. The theoretical operation of a multi-stage coilgun is introduced, and a transient simulation was conducted for projectile motion through the launcher by using a commercial transient finite element software, ANSOFT MAXWELL. The excitation circuit design for each coilgun is reported, and the results indicate that the overlapped configuration increased the exit velocity relative to a non-overlapped configuration. Different configurations in terms of the optimum length and switching time were attempted for the proposed structure, and all of these cases exhibited an increase in the exit velocity. The exit velocity tends to increase by 27.2% relative to that of a non-overlapped coilgun of the same length.
https://doi.org/10.4283/JMAG.2015.20.3.322 인용 PDF KSCI

Yoo, Yong-Goo;Yu, Seong-Cho;Min, Seong-Gi;Kim, Kyeong-Sup;Jang, Pyung-Woo
- Journal of Magnetics
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- 제6권4호
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- pp.129-131
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- 2001
In order to investigate the effect of the interface on GMR, [NiFe(25 ${\AA}$)/Cu(24${\AA}$)]$_2$/Si thin film was epitaxially grown on HF-treated Si (001) substrate using a DC magnetron sputtering method. Typical GMR effects could be observed in epitaxial film with a weak antiferromagnetic exchange coupling while non epitaxial film showed unsaturated and broad MR curves probably due to inter-diffusion between NiFe and Cu layers. Ferromagnetic resonance (FMR) experiment showed two distinct absorption peaks in all films. Each peak was revealed to come from each NiFe layer with different magnetic property. In FMR measurement very clear interface in epitaxial films could be confirmed by a lower value of line width (ΔH) and higher M$\sub$s/ of epitaxial film than those of non epitaxial films, respectively.
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Lachowicz, H.K.;Poplawsi, F.;Zuberek, R.;Kuzminski, M.;Slawska-Waniewska, A.;Dynowska, E.;Yu, S.C.
- Journal of Magnetics
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- 제4권3호
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- pp.84-87
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- 1999
It is shown that progressive crystallization of non-magnetostrictive Co-based metallic glass (VITROVAC 6030) leads to an increase of coercivity by more than three orders of magnitude. The mechani는 responsible for this phenomenon are interpreted showing that the main source for the giant increase of the coercivity is the pinning effect on the domain walls originating from the created crystallites of the size much smaller than the domain width (correlation length for ferromagnetic exchange interactions). It is also shown that gradually devitrified non-magnetostrictive metallic glass is an excellent model material for verification of N el's theory describing the Rayleigh rule.
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Rahman, Nazaruddin Abd;Mahadi, Wan Nor Liza
- Journal of Magnetics
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- 제18권1호
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- pp.9-13
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- 2013
Shielding effects in conductive and magnetic materials were investigated as a function of properties, thickness and diameter. In this work, evaluations on passive conductive and magnetic shield specimens were achieved through experimentation set-up using 50 Hz single and three phase induction field sources. Analysis on material microstructure properties and characteristics of shielding specimens were performed with the use of vibrating sample magnetometer (VSM) and field emission scanning electron microscopy (FESEM). An induction field at $136{\mu}T$ of single phase system and $50{\mu}T$ of three phase systems were observed to the shield specimens with the thickness ranged of 0.2 mm to 0.4 mm. It is observed that shield specimen efficiency becomes inversely proportionate to the increment of induction fields. The decrease was attributed to the surface structure texture which relates to the crystallization and non-crystallization geometrical effects.
https://doi.org/10.4283/JMAG.2013.18.1.009 인용 PDF KSCI