• 한국자기학회지
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• 제3권1호
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• pp.61-64
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• 1993

비정질 세선(amorphous wite)의 인장응력(tensile strees)에 대한 자기적 특성의 변화를 측정하기 위하여 자화 주파수 범위가 1~20 kHz, 인장응력의 범위가 0~20인 N인 비정질 세선용 교류자 기이력곡선특성 측정장치를 제작하였다. 제작된 교류자기이력곡선 측정장치를 이용하여 비정질 세선의 인장응력에 따른 자기적 특성 (최대자기유도 $B_{max}$, 잔류자기 유도 $B_{r}$, 보자력 $H_{c}$)을 1% 의 정밀도로 측정할 수 있었다.

• Journal of Magnetics
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• 제21권3호
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• pp.322-329
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• 2016

In this paper, we propose an array sensing detection method for smelting of submerged arc furnaces (SAF) based on electromagnetic radiation. AC magnetic field generated by electrode currents and molten currents in the furnace is reflected outside of the furnace. According to the spatial distribution of electromagnetic field a radiation model of SAF is built. We design a 3D magnetic field sensing array system in order to collect the magnetic field information. Through the collected information, the current distribution characteristics of SAF are described and the key parameters of smelting are obtained. Theoretical simulation and field test show that the curves acquired by the sensing array can accurately reflect the information of the relative displacement when the relative displacement between the array and electrode is 10 cm. Compared with the detection method of 3D single point, the proposed array sensing method of magnetic field obtains better results in terms of real-time and accuracy, and has good practical value for industrial measurement.

• 한국연소학회지
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• 제16권2호
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• pp.33-39
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• 2011

We demonstrated heat generation efficiency of the magnetic hyperthermia system to find optimal condition using gelatin tissue phantom. Magnetic hyperthermia induction can be used to make heat generation with different concentration of $Fe_3O_4$ iron oxide inside tissue phantom and magnetically labeled cells by applying AC magntic field at a frequency of 145 kHz. It was observed that the maximum temperature achieved in the magnetic gelatin tissue phantom increased with the concentration of $Fe_3O_4$ iron oxide and alternating magnetic field intensity. Results were discussed with respect to further optimization of therapeutic technique for biomedical application with modified functional nanoparticles.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 추계학술대회 논문집 전력기술부문
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• pp.96-100
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• 2001

Bi-2223 tapes have been developed for low-field power applications at liquid nitrogen temperature. When the Bi-2223 tapes are used in an application such as a power transmission cable or a power transformer, they are supplied with an AC transport current and exposed to an external magnetic field generated by neighboring tape's AC currents simultaneously. AC loss taking into account such real applications is a crucial issue for power applications of the Bi-2223 tapes to be feasible. In this paper, the transport losses for different AC current levels and arrangements of the neighboring tapes have been measured in a 1.5 m long Bi-2223 tape. The significant increase of the transport losses due to neighboring tape's AC currents is observed. An increase of the transport losses caused by a decrease of the Bi-2223 tape's critical current is a minor effect. The measured transport losses could not be explained by a dynamic resistance loss based on DC voltage-current characteristics in combination with the neighboring tape's AC currents. The transport losses do not depend on the frequency of the neighboring tape's AC currents but its arrangements in the range of small current especially.

• 에너지공학
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• 제2권1호
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• pp.38-44
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• 1993

Electromagnetic seawater thrusters may be classified into four general categories : internal duct dc, external field dc, internal peristaltic ac, and external peristaltic ac. Internal duct dc thrusters offer the advantages of low magnetic field leakage, simple construction, and potentially high reliability. The most efficient internal duct configuration consists of converging inlet nozzle and a straight discharge duct. Ideal efficiency calculations based on the one-dimensional Bernoulli equation show that thrusters should be designed with large cross-sectional areas and operate at low discharge velocities. In practice, this may be accomplished by using multiple thruster ducts. Conductivity enhancement, high magnetic fields, and long electrodes will also improve efficiency.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제48권5호
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• pp.233-240
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• 1999

The current carrying conductor and the tank which consist of GIS must be properly designed to withstand the electrical, thermal and mechanical stresses that arise during normal service and during short-circuit conditions. In order to design the current carrying conductor for EHV GIS, it is important to consider temperature-rise when rated current flows. In this paper, we analyze magnetic field distribution and power-loss, according to the change of materials when AC current flows into single-phase and three-phase bus bar, respectively. These results will be used as the basic design data when determining dimensions and materials for the current carrying conductor of EHV GIS.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 학술대회 논문집 전문대학교육위원
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• pp.64-66
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• 2002

This study is to develop electromagnetic plasma reactors for indoor air purification, Removal effect of nitrogen oxide using magnetic field are investigated. And AC or DC high voltage is applied for corona discharge, flow rates are 150${\sim}$1500${\ell}$/min and NO initial concentration is about 10 ppm. In the results, NOx removal rate by AC power is about 10 % higher than that by DC power under the experimental condition of 700 ${\ell}$/min, 5 magnets. When magnet is applied to the reactor, NOx removal rate increased.

• KIEE International Transactions on Electrophysics and Applications
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• 제3C권6호
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• pp.211-215
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• 2003

Alternating current (AC) losses of two Bi-2223 ([Bi, Pb] : Sr : Ca : Cu :O = 2:2:2:3) tapes [one untwisted (Tape I, twist-pitch of $\infty$ mm) and the other with a twist-pitch of 8mm (Tape II) ] were measured and compared. These samples, produced by the powder-in-tube (PIT) method, are multi-filamentary and have a Ag/Au and Ag matrix, respectively. Susceptibility measurements were conducted while cooling in a magnetic field. Flux loss measurements were conducted as a function of ramping rate, frequency and field direction. The AC flux loss increases as the twist-pitch of the tapes decreased, in agreement with the Norris Equation.

• 조명전기설비학회논문지
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• 제24권3호
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• pp.33-38
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• 2010

In this paper, the nature of iron loss in electrical steel during alternating field excitation is investigated more precisely. The exact definition of AC iron loss is cleared by accurately measuring the iron loss for conditions of both the sinusoidal magnetic field and sinusoidal magnetic flux density. The results of this approach to iron loss calculations in electrical steel are compared to experimentally-measured losses. In addition, an inverse hysteresis model considering eddy current loss was developed to analyze the iron loss when the input is the voltage source. With this model, the inrush current in the inductor or transformer as well as the iron loss can be calculated.

• 한국생산제조학회지
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• 제20권3호
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• pp.251-256
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• 2011

Instead of multi-phase ac current, the magnetic field travels spatially through mechanical rotation of permanent magnets at the electrodynamic wheel (EDW). Traveling of magnetic field generally leads to a generation of inductive force in the traveling direction. In this paper, we suggest a spiral EDW to travel the magnetic field in the axial direction of the conductive rod. So, it is possible to levitate and transfer the rod through multi-axial forces by the spiral EDW. However, physical dimensions of permanent magnets constituting EDW influence relative ratios between three-axial forces generated on the rod. Therefore, the sensitivity analysis for design parameters is performed using FEM analysis. The stable operation is verified experimentally.