• Proceedings of the KIPE Conference
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• 2002.07a
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• pp.723-726
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• 2002

In this paper, a high efficiency leakage transformer for neon tube is developed to improve its power factor, to reduce its core loss and weight by using a technique of shape optimization and direction of grain-oriented silicon steel sheet. A protection circuit is designed for all types of neon transformer loaded with one or more neon lamps. Whenever the neon tube fails to be started up or comes to the life end, or encounters faults with open-circuits at the output terminals of the neon transformer, the protection circuit will be initiated to avoid more critical hazards. These neon transformers need a protection circuit to prevent from current stresses on circuit components by neon tube fail. The input of the transformer is automatically cut off when the abnormal condition occurs, preventing waste of no-load power. As the results of the study, the core weight is reduced by $11\%$, the power factor improved by $5\%$ and the efficiency increased by $6\%$ compared with the conventional type due to the employment of the grain-oriented steel sl)eel and the optimized core shape.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.58 no.2
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• pp.190-195
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• 2009

Thin-gauged 3% silicon steel sheets having a highly grain-oriented texture have been developed as a core material for applications of middle-frequency (400 Hz ${\sim}$ 10 kHz) devices. The newly developed sheets with a tension coating showed an excellent reduction in iron loss at 400 Hz (iron loss at 1.0 T and 400 Hz = 4.677 W/kg, iron loss at 1.5 T and 400 Hz = 9.742 W/kg) due to high magnetic induction, $B_{10}$(measured induction at 1000 A/m), of over 1.9 T. In cases of frequencies below 400 Hz, magnetic induction, $B_{10}$, of the sample plays a major role to reduce its iron loss as excitation induction increases, whereas, in case of frequency of 1 kHz, thickness dependence becomes dominant due to a lower iron loss at relatively thinner sample. The sheets with a high magnetic induction, therefore, are favorable for high excitation induction (over 1.0 T) and low excitation frequency (below 400 Hz) applications, whereas the sheets that can reduce eddy current loss by reducing thickness or domain wall width are advantageous for low excitation induction (below 1.0 T) and high excitation frequency (around 1 kHz) applications.

• Nuclear Engineering and Technology
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• v.3 no.3
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• pp.129-140
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• 1971

Two laboratory-melt heats of 3.25 silicon-iron were made and processed according to a normal commercial practice. Some of the important processing variables that were studied in relation to secondary recrystallization and texture development were contents of manganese and sulfur, heat-treatments after hot-rolling that were used to achieve different hot-rolled microstructures, and amounts of second cold-reduction. The main effort of the present study was directed toward elucidating the relationships among the amount of second cold-reduction, activation energies associated with secondary recrystallization and texture development. The specimens that had been cold-reduced 10% exhibited only grain growth by strain-induced grain boundary migration and did not exhibit secondary recrystallization. Secondary recrystallization did rot appear to completely occur in the 30% cold-reduced specimens, although the nucleation for secondary recrystallization was observed. The second cold-reduction in an amount of 50% was shown to be the optimun for secondary recrystallization and texture development by subsequent processing.

• 전기의세계
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• v.20 no.3
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• pp.17-26
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• 1971

An experimental design of magnetic amplifiers and their characteristics in steady state are presented. A saturable reactor model having 2KVA capacity was designed, using Z-10 grain-oriented silicon steel which is commonly used in power transformers. Experimental and theoretical analysis show that the experimental results are in good agreement with the equal ampere-turns law. In addition to the saturable reactor, the self-saturated magnetic amplifiers of 0.4VA and 5VA capacity, using 50% Ni-Fe alloy cores having rectangular hysteresis loops were designed. Control characteristic curves of these amplifiers show high ampere-turn gain enough to be used for voltage controllers under load and non-contact magnetic switches of the rated capacity.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• v.2B no.4
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• pp.143-148
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• 2002

Up to now, DC-biased magnetic properties have been measured in one dimension (scalar). However, scalar magnetic properties are insufficient to clarify DC-biased magnetic properties because scalar magnetic properties can only impossibly consider the phase difference between the magnetic flux density B vector and the magnetic field strength H vector. Thus the magnetic field strength H and magnetic flux density B in magnetic materials must be directly measured as a vector quantity (two-dimensional). This paper presents measurement system to clarify the two-dimensional DC-biased magnetic properties.

• Proceedings of the KIPE Conference
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• 2001.10a
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• pp.93-97
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• 2001

A new compact, low-energy electron beam irradiator has been developed. The core-loss of silicon steels can be reduced by magnetic-domain refinement method. The irradiator was developed for the application of core-loss reduction using the method. The beam energy of the irradiator can be varied from 35 to 80 keV and the maximum current is 3mA. The irradiation area is designed to be $30\times30mm2$ now and will be upgraded to $30\times150mm2$ using a scanning magnet and scanning cone. The electron beam generated from 3 mm diameter LaB6 is extracted to the air for the irradiation of the silicon steels in the air. A special irradiation port was developed for this low-energy irradiator. A havar foil with $4.08{\mu}m$ thickness were used for the window and a cold air-cooling system keeps the foil structure by removing heat at the window. The irradiator system and its operation characteristics will be discussed.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.20 no.7
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• pp.639-647
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• 2009

In this work, wrapping conductors with thin magnetic materials is proposed as a magnetic shielding method. The 0.1 mm thick metal sheets of mu-metal, grain-oriented electrical steel, and non-oriented electrical steel were produced from commercial alloy sheets through cold rolling and followed high temperature annealing. In case of 3-phase electric currents, mu-metal was the best in shielding performance at a B-field magnitude of about 100 ${\mu}T$, whereas silicon steels were better than mu-metal at a B-magnitude over 500 ${\mu}T$. In addition, wrapping with silicon steel(inner) together with mu-metal(outer) resulted in a shielding factor less than 0.1 even at 500 ${\mu}T$. These results are due to changes in hierarchy of magnetic permeabilities of the materials with increasing magnetic field strength. In case of single-phase electric current, B-magnitude outside the magnetic shell was rather increased compared to the unshielded case. This result is explained by vector composition of B-fields near magnetic shielding materials.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.11a
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• pp.343-344
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• 2006

방향성 규소강판을 tape-wound core 형태로 제작하여 가공방법에 따른 자기적 특성을 조사 하였다. 그 결과 곡률반경이 40mm인 시료에서 보자력(Hc)과 포화자속밀도(Bs)는 우수한 값을 나타내었고, 보자력은 0.02Oe, 포화자속밀도는 1.85T 이었다. 현재 국내에서 생산되고 있는 방향성 규소강판의 자속밀도값 보다 우수한 값을 나타내었다. 본 연구로부터 방향성 규소강판을 이용하여 권자심을 제작할 때 도입되는 탄성변형에 대한 대책의 중요성과 코어 소재의 가공방법이 자기적 특성에 미치는 영향을 통해 고효율 방향성 규소강판 개발의 가능성을 확인하였다.

• Journal of the Korean Ceramic Society
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• v.32 no.7
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• pp.809-816
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• 1995

Ti1-xAlxN films were successfully deposited on high speed steel and silicon wafer by plasma-assisted chemical vapor deposition using a TiCl4/AlCl3/N2/Ar/H2 gas mixture. Plasma process enabled N2 gas to nitride AlCl3, which is not possible in sense of thermodynamics. XPS analyses revealed that the deposited layer contained Al-N bond as well as Ti-N bond. Ti1-xAlxN films were polycrystalline and had single phase, B1-NaCl structure of TiN. Interplanar distance, d200, of (200) crystal plane of Ti1-xAlxN was, however, decreased with Al content, x. Al incorporation into TiN caused the grain size to be finer and changed strong (200) preferred orientation of TiN to random oriented microstructure. Those microstructural changes with Al addition resulted in the increase of micro-hardness of Ti1-xAlxN film up to 2800Kg/$\textrm{mm}^2$ compared with 1400Kg/$\textrm{mm}^2$ of TiN.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.06a
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• pp.245-246
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• 2006

방향성 규소강판을 tape-wound core 형태로 제작하여 $N_2$ gas 분위기에서 $760^{\circ}C$ 4 시간동안 열처리후 자기적 특성을 조사 하였다. 그 결과 1차, 2차 권선수가 85 turns 시료에서 보자력(Hc)과 포화자속밀도(Bs)는 최대값을 나타내었고, 보자력은 0.019Oe, 포화자속밀도는 1.92T 이었다. 현재 국내에서 생산되고 있는 방향성 규소강판의 자속밀도값 보다 더 우수한 값을 나타내었으며, 열화특성이 자기적 특성에 미치는 영향을 통해 고효율 방향성 규소강판 개발의 가능성을 확인하였다.