• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2000년도 영호남학술대회 논문집
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• pp.216-221
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• 2000

This paper describes the analysis results on the PT ferroresonance at 154 kV GIS (gas Insulated substation by EMTP(Electro- magnetic Transient Program). We had simulated the PT ferroresonance between a potential transformer(PT) and an open circuit breaker's grading capacitance. The ferroresonance leads to very large power frequency overvoltages on PT bus and subsequent insulation failure. The large power can be supplied to the PT by the high voltage on the opened circuit due to the grading capacitance and equivalent capacitance of the buses during the ferroresonance. The damping circuit connected on the secondary winding were considered in the model. The actual countermeasure include a saturable inductor and a resistor series-mounted, but the 2 ohms of damping resistance was used in the computationl model.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2010년도 하계학술대회 논문집
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• pp.261-261
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• 2010

In electric railways, high speed trains are normally supplied by AC 25kV power by contact between a pantograph contact strip and a contact wire. Advanced railway operating countries are actively researching various areas for the development of contact strips due to the reason that the properties of contact strips are one of the key factors of electric railways. This paper applied nano technology which is rapidly growing in many areas to the contact strip of a pantograph for current collection performance improvement considering speed up of electric railways. In detail, this paper proposes a method to dope nano particles of metal to a Korea Train eXpress(KTX) carbon pantograph and its measurement results. It is expected that the contents of this paper be used for preliminary study of high-speed railway current collection technologies.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2001년도 The 6th International Symposium of East Asian Resources Recycling Technology
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• pp.102-105
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• 2001

Gypsum has been known as a prominent material for improving alkali soil, and this material can be supplied easily in large scale by recycling waste gypsum plasterboard from construction and demolition sites in advanced countries. In April 2000, in the part of western Jilin Province in China, where alkali soil spread vastly, we conducted a cultivating experiment of corn and rice after treating with granule recycled waste gypsum at six alkali soil fields which total area were 14000$m^2$. We confirmed that pH of soil decreased in a short period and alkali soil changed soft a desirable condition for farm work, and furthermore, gypsum caused to accelerate the growth of a plant, both corn and rice.

• 산업경영시스템학회지
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• 제29권3호
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• pp.128-134
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• 2006

The most of national industrial complex were developed and supplied not according to the requirements of enterprise but the needs of the government. And it leads to current serious out of balance in demand and supply of industrial complex. Buckpyoung industrial complex started sale from when the industrial complex developed in 1995 however the unsold percentage of it was 67% until in October,2005. And this result was ranked the top in the unsold percentage among the 42 national industrial complex in korea. In this paper we research how to accelerate the sale of Buckpyoung industrial complex and to reinvigorate local economy and present the constitution of building material cluster and physical distribution system as the results of our research.

• Wind and Structures
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• 제16권3호
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• pp.241-248
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• 2013

The wind turbine blade is a very important part of the rotor. Extraction of energy from wind depends on the design of blade. In this work, the analysis is done on a blade of length 38.95 m which is designed for V82-1.65 MW horizontal axis wind turbine (supplied by Vestas). The airfoil taken for the blade is NACA 634-221 which is same from root to tip. The analysis of designed blade is done in flap-wise loading. Two shapes of the spar are taken, one of them is of square shape and the other one is combination of square and cross shape. The blade and spar are of the same composite material. The Finite element analysis of designed blade is done in ANSYS. This work is focused on the two segments of blade, root segment and transition segment. Result obtained from ANSYS is compared with the experimental work.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2003년도 하계학술대회 논문집 Vol.4 No.1
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• pp.19-27
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• 2003

Morphology and composition of MgO films grown on single-crystalline diamond (100) have been studied. MgO thin films were deposited in the substrate temperature range from room temperature (RT) to 723K by means of electron beam evaporation using MgO powder source. Atomic force microscopy images indicated that the film grown at RT without $O_2$ supply was relatively uniform and flat whereas that deposited in oxygen ambient yielded higher growth rates and rough surface morphologies. X-ray photoelectron spectroscopy analyses demonstrate that the MgO film deposited at RT without $O_2$ has the closest composition to the stoichiometric MgO, and that a thin contaminant layer composed mainly of magnesium peroxide (before etching) or hydroxide (after etching) was unintentionally formed on the film surface, respectively. These results will be discussed in relation to the interaction among the evaporated species and intentionally supplied oxygen molecules at the growth front as well as the interfacial energy between diamond and MgO.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2005년도 추계학술대회 논문집 Vol.18
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• pp.331-332
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• 2005

Ozone is ambient gas which is useful for the fabrication of metal oxide thin films under conditions of molecular beam epitaxy. Ozone is condensed by the adsorption method and its concentration is analyzed using the thermal decomposition method. The concentration of ozone exceeds 90 mol% and ozone is supplied for a sufficiently long time to grow oxide thin films. The ozone concentration is also evaluated using a quadrupole mass analyzer and the accuracy of this method is compared with the results of the thermal decomposition method.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2005년도 추계학술대회 논문집 Vol.18
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• pp.329-330
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• 2005

Bi-Sr-Ca-Cu-O thin films have been fabricated by sputter deposition method. During the deposition, 10 and 90 wt%-ozone/oxygen mixture gas of typical pressure of $1\sim9\times10^{-5}$ Torr are supplied with ultraviolet light irradiation for oxidation. XRD and RHEED investigations reveal out that a buffer layer with some different compositions is formed at the early deposition stage of less than 10 units cell and then Bi-2201 oriented along the c-axis is grown.

• Journal of Magnetics
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• 제8권2호
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• pp.79-84
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• 2003

Finite element analysis showed that strong magnetic fields were distributed around the arc furnace where the strongest magnetic fields were generated around the three phase cables. The second and third strongest fields near the arc furnace were found to be generated around the electrodes and the mast-arms, respectively. The generated field intensities were greatly influenced by the mast arm structure of the arc furnace as well as the phase differences and operation currents of the supplied power, Magnetic field decay patterns around the arc furnace could be smoothly fitted by this equation of exponential formula, H=H$0_$+Ae$^{\frac{r}{t}}$. These results revealed that magnetic field intensities around the arc furnace could be estimated at any 3-dimensional position using finite element method (FEM).

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 추계학술대회 논문집 Vol.15
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• pp.272-275
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• 2002

An ozone condensation system is evaluated in the viewpoint of an ozone supplier for oxide thin film growth. Ozone is condensed by the adsorption and distillation method. Then their concentrations are analyzed by three methods; ultraviolet absorption, thermal decomposition and Q-mass analyzing methods. Thermal decomposition method is found to be available to the concentration evaluation from dilution to highly condensed ozone. The highest ozone concentration condensed by the adsorption method is evaluated to be 96 mol%. The ozone is supplied for a sufficiently long time to grow oxide thin films.