• 전기학회논문지
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• 제57권12호
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• pp.2238-2243
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• 2008

The use of arc tubes made of ceramic material further enhanced some of the metal halide lamp's properties. These properties translate into higher efficacy with better color rendering, stable color through lamp long life. Recently, due to an increase in the application of the ceramic metal-halide lamp, the study for the property etc. according to Ballast's driving scheme and the study for arc tube material, optimization of gas and so on are being proceeded to improve the property of the lamp. Especially, to control ceramic metal-halide lamp, the vigorous study and practical use with respect to Electronic Ballast, which has been improved in the disadvantages of the conventional Magnetic Ballast are made. In this paper, Electrical, optical and thermal characteristics are analyzed by comparing magnetic ballast with electronic ballast.

• Journal of Magnetics
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• 제21권2호
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• pp.179-182
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• 2016

In this paper, 10 nm $Fe_3O_4$ nanoparticles were modified on the surface of $2{\mu}m$ flower-like bismuth oxychloride (BiOCl) spheres by a facile co-precipitation method. The results showed that the $Fe_3O_4/BiOCl$ nanocomposites exhibited excellent photocatalytic activity and superparamagnetic property ($M_s=3.22emu/g$) under visible light for Rhodamine B (RhB) degradation. Moreover, the $Fe_3O_4-BiOCl$ photocatalyst possessed magnetic recyclable property, which could maintain high photocatalytic effective even after 20 cycle times. These characteristic indicates a promising application for wastewater treatment.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2000년도 하계학술대회 논문집
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• pp.519-522
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• 2000

The correlation of surface morphology and magnetic property of NiFe thin films on Si(001) deposited by RF-magnetron sputter has been investigated, using AFM, XRD and MR measurements. During short field annealing for 15 min, there was no significant change in XRD patterns of NiFe thin films. However, the degree of surface roughness was changed with increasing annealing temperature. With variation of surface roughness, there was significant difference in MR characteristics of NiFe thin films. In the case of as-deposited NiFe thin films(T$\_$G/ = 150$^{\circ}C$) and UFA400 (T$\_$A/ = 400$^{\circ}C$) having smooth surface, good linearity of MR Curve was observed.

• 한국기계연구소 소보
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• 통권20호
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• pp.41-48
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• 1990

Electro-pneumatic valves are an electro-mechanical device which convert electric signal into pneumatic flow rate or pressure signal. Recently, the development tendency of electro-pneumatic valve is to make the valve with more compact and less electric power consumption style. To make the valve such as a style, the role of solenoid part is very important. This paper is used in the finite-element method for the purpose of evaluating the magnetic property of solenoid and analyze flux distribution of solenoid theoretically. From flux contour line which is obtained by numerical analysis, it verified that the plunger shape and physical property of solenoid part have influence on saturation phenomenon and leakage of magnetic fluxs. This paper made an experiment on the measurement of dynamic response time and force in order to confirm the propety of analytic result, and confirmed a good agreement between analysis results and experiment results.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2002년도 춘계학술대회논문집
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• pp.67-70
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• 2002

This paper presents the property of the Squeeze Film Damper (SFD) using Magneto-Rheological fluid (MR fluid). The damping property of a SFD for a flexible rotor system varied according to vibration mode. MR fluid is known as a functional fluid with controllable apparent viscosity of the fluid by applied magnetic field strength. When the MR fluid is applied in the SFD, the SFD using MR fluid can effectively reduce vibrations of the flexible rotor in a wide range of rotating speed by control of the applied magnetic field strength. To investigate in detail the SFD using MR fluid, the SFD to support one mass was constructed and its performance was experimentally investigated in the present study. The damping property of the SFD using MR fluid has viscous damping by Newtonian fluid, but not Coulomb friction by Bingham fluid. Therefore, The system damped by the SFD can be considered as a linear system.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part2
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• pp.1169-1170
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• 2006

We made a high-speed motor and a DC brush-less motor for factory automation (FA) to investigate applicability of powder magnetic core to motor application, and compared those performances with the similar motors having conventional electro magnetic steel core. Permeability and saturated magnetization of powder magnetic core are less than those of elect romagnetic steel core, however output performances of each core motor are almost the same. The FA motor with powder magnetic core using three-dimensional magnetic circuit showed higher torque than the same volume motor with electromag netic steel core.

• 한국표면공학회지
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• 제26권2호
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• pp.45-54
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• 1993

In this study, magnetic properties of anodized Al film deposited with ferro-magnetic metals in the capacity of perpendicular magnetic recording media were measured and evaluated to find out the role of structure and morphology of the oxide films on magnetic characteristics. The object of this work was to present the conditions of magnetic thin film formation with more superior magnetic property. Anodizing was carried out under various conditions, and then the anodized film were electro-deposited with Co, Ni, Fe and their alloys. Coercive force and residual magnetization in perpendicular direction increased as the pore length of anodized film increased. It was attributed to the increase of the amount of depoisted metals and the ratio of length/diameter of pores. Morphology of anodized films in phosperic acid was not similar to that of sulfuric acid, and thin films in the former solution had perpendcular magnetic anisostropy because of large diameter, irregular length and distribution of the pores. It was found that magnetic properties of the thin films, which had doubled layer of two metals, were dominated by the metal electrodeposited on the surface of the anodized oxide films.

• Journal of Magnetics
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• 제14권1호
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• pp.1-6
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• 2009

The magnetic properties of ${Bi_x}{Ca_{1-x}}{MnO_3}$ for x = 0.12, 0.13, 0.14, 0.15, and 0.16 were examined by measuring magnetic susceptibility, resistivity and electron magnetic resonance at different temperatures. ${Bi_x}{Ca_{1-x}}{MnO_3}$ showed complicated magnetic structure that varies with temperature and composition, particularly around Bi composition x. 0.15. The aim of this study was to determine how the magnetic and physical properties of ${Bi_x}{Ca_{1-x}}{MnO_3}$ change in this region. In addition, first principles calculations of the magnetic phase of ${Bi_x}{Ca_{1-x}}{MnO_3}$ for x = 0, 0.125, 0.25 were carried out, and the spin state, electric and magnetic characteristics are discussed.

• 비파괴검사학회지
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• 제20권5호
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• pp.438-444
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• 2000

WC-Co 초경합금의 항자력과 자기포화도를 평가하여 합금조직과 이에 따른 기계적 성질의 예측에 관해 연구하였다. WC 입경이 다르고 탄소함량 및 소결온도가 다른 WC-8%-Co 초경합금을 분말 야금법에 의해 제조하였다. 항자력과 자기포화도와 같은 WC-Co 합금의 자기적 특성은 합금조성 및 조직에 크게 의존하였다. 미소한 합금탄소량의 변화와 WC 입도의 차이에 의해서도 WC-Co 합금의 자기적 특성과 경도 및 항절력이 크게 변화하였다. WC 입도가 미세할수록 소결합금의 항자력과 경도는 증가하였고, 항자력은 경도의 증가와 비례하였다. WC-8%Co 합금의 화학 양론적 조성 아래로 카본함량이 감소하면 자기포화도와 항절력이 떨어지고 $\eta$상의 체적률도 꾸준히 증가하였다. WC-Co 합금에 있어서 자기포화도는 항자력과 반비례하였다.

• 한국자기학회:학술대회 개요집
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• 한국자기학회 2009년도 정기총회 및 동계학술연구발표회
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• pp.212-212
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• 2009