• The Transactions of the Korean Institute of Electrical Engineers C
• /
• v.55 no.2
• /
• pp.76-81
• /
• 2006

This paper analysed the characteristics of current density induced inside human body by 60 Hz extremely low frequency magnetic fields according to varying conductivities of human model. Human model was composed of several organs and other parts, whose shapes were expressed by spheroids or cylinders. Organs such as the brain, heart, lungs, liver and intestines were taken into account. Applying the boundary element method to the human model, we estimated effects on the induced current distribution due to differences of the organ conductivity and shape. We find organ conductivity influences most and a cross section area and a position of organ also gives effects.

• Smart Structures and Systems
• /
• v.25 no.6
• /
• pp.707-717
• /
• 2020

In this paper, analysis of thermal post-buckling behaviors of sandwich nanobeams with two layers of multi-phase magneto-electro-thermo-elastic (METE) composites have been presented considering geometric imperfection effects. Multi-phase METE material is composed form piezoelectric and piezo-magnetic constituents for which the material properties can be controlled based on the percentages of the constituents. Nonlinear governing equations of sandwich nanobeam are derived based on nonlocal elasticity theory together with classic thin beam model and an analytical solution is provided. It will be shown that post-buckling behaviors of sandwich nanobeam in thermo-electro-magnetic field depend on the constituent's percentages. Buckling temperature of sandwich nanobeam is also affected by nonlocal scale factor, magnetic field intensity and electrical voltage.

• Journal of the Korean Ceramic Society
• /
• v.28 no.8
• /
• pp.640-646
• /
• 1991

Recently intensive studies have been focussed on ferrites which have high magnetic loss because of the increasing need for the prevention of EMI (Electromagnetic Interference). We investigated effects of microstructures of Ni-Zn ferrites on magnetic losses, magnetic properties, and behaviors of electromagnetic wave absorbers. The characteristics of the absorber were influenced by the sintering conditions. A Ni-Zn ferrite with the thickness of 7$^{\circ}C$/min and the cooling rate of 7$^{\circ}C$/min. It satisfied the absorbing properties in the wide frequency ranges including VHF (90∼220 MHz), UHF (470∼770 MHz)

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
• /
• v.11B no.2
• /
• pp.15-21
• /
• 2001

This paper presents an improved characteristic analysis methodology for a 5-phase hybrid stepping motor. The basic approach is based on the use of equivalent magnetic circuit taking into account the localized saturation throughout the hybrid stepping motor. The finite element method(FEM) is used to generate the magnetic circuit parameters for the complex stator and rotor teeth and airgap considering the saturation effects in tooth and poles. In addition, the neural network is used to map a change of parameters and predicts their approximation. Therefore, the proposed method efficiently improves the accuracy of analysis by using the parameter characterizing localized saturation effects and reduces the computational time by using the neural network. An improved circuit model of 5-phase hybrid stepping motor is presented and its application is provided to demonstrate the effectiveness of the proposed method.

• Journal of Korea Foundry Society
• /
• v.40 no.4
• /
• pp.113-117
• /
• 2020

A series of Fe-P-B and Fe-Si-B amorphous alloys with high Fe contents exceeding 90 wt.% was successfully prepared by combining flux treatment and melt-spinning technique. The effects of Fe content and the flux treatment on the thermal and magnetic properties of amorphous alloys were studied. The glass-forming ability and the thermal stability of amorphous ribbons can be improved by a flux treatment, revealing the effective removal of heterogeneous nucleation sites in the ribbons through the flux treatment. It was found that Fe-Si-B ribbons exhibit higher saturation magnetization levels than Fe-P-B ribbons.

• Journal of Magnetics
• /
• v.18 no.1
• /
• pp.9-13
• /
• 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.

• Proceedings of the KWS Conference
• /
• 2008.05a
• /
• pp.4-4
• /
• 2008

• 한국초전도학회:학술대회논문집
• /
• 2008.08a
• /
• pp.93-93
• /
• 2008

• Proceedings of the Korean Magnetic Resonance Society Conference
• /
• 2002.08a
• /
• pp.83-83
• /
• 2002

• Journal of the Korean Magnetics Society
• /
• v.5 no.5
• /
• pp.583-588
• /
• 1995

Fe rich nanocrystals embedded in an amorphous magnetic matrix have been shown to exhibit outstanding soft magnetic properties. The cause of softness in the exchange coupling between the two-phases. In this paper some effects of the exchange coupling between the nanocrystals and the matrix are reviewed.