• 대한전기학회:학술대회논문집
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• 대한전기학회 1997년도 하계학술대회 논문집 F
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• pp.2082-2084
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• 1997

This paper proposes a new control strategy of bidirectional uninterruptible power supply(UPS) with the performance of active power filter which compensate the harmonics and reactive power. To improve the transient response for the effective compensation in active power filter mode, it is considered that a simple and precise calculation method of the compensation reference current for the harmonics and reactive power compensation. So a novel closed-loop control strategy is used to calculate the reference current. And the current regulated instantaneous voltage control scheme is used in back-up power mode. The system model and control algorithm are described and analyzed, and the system Performance is verified by the simulation and experimental results.

• 한국잠사곤충학회지
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• 제27권1호
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• pp.42-46
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• 1985

반응성 염료의 하나인 vinylsulfone계 염료로 견섬유에 날염하여 증열시간, 호료의 점도, 알카리 농도에 의한 염료량 및 고착량의 변화를 측정하여 반응성 염료의 견에 대한 날염 특성을 검토하고 연구한 결과를 다음과 같이 요약한다. 1) 증열 시간과 더불어 염착량 및 고착량은 증가하였으며 염착량과 고착량은 비례관계를 나타내고 있다. 2) 고착율은 80% 이상으로 높은 고착율을 나타내고 있다. 3) 호료의 점도에 따라 염착량과 고착량이 달라지며 적당한 점도가 요구됨을 시사한다. 4) 알카리 농도는 염착량과 고착량의 변화에 큰 영향을 주는 요인이었으며 적당량의 알카리 첨가가 필요함을 나타낸다. 5) 세탁 견뢰도와 일광 견뢰도가 뛰어났으며 실용상 매우 우수한 염료임이 입증되었다. vinylsulfone계 염료는 우수한 발염성과 견뢰도를 가지고 있어서 견질물의 염색분야에 충분한 응용을 기할 수 있다.

• Transactions on Electrical and Electronic Materials
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• 제14권6호
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• pp.317-320
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• 2013

Partial discharge resistance for the epoxy systems with two diluents was investigated in the rod-plane electrodes arrangement, and the effect of electric frequency on the partial discharge resistance was also studied. Diglycidyl ether of bisphenol A (DGEBA) type epoxy was used as a base resin, and 1,4-butanediol diglycidyl ether (BDGE) or polyglycol (PG) as a reactive diluent was introduced to the DGEBA system, in order to decrease the viscosity of the DGEBA epoxy system. BDGE was acted as a chain extender, and PG acted as a flexibilizer, after the curing reaction. To measure the partial discharge resistance, 5 kV alternating current (ac) with three different frequencies (60, 500 and 1,000 Hz) was applied to the specimen in a rod-plane electrode arrangement, at $30^{\circ}C$. PG had a good effect, while BDGE had a bad effect on the partial discharge resistance of the DGEBA system, regardless of the electric frequency.

• 전기학회논문지
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• 제59권8호
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• pp.1353-1359
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• 2010

This paper presents the determination of synchronous compensator(S.C) rating and parameter in Cheju AC network. The role of S.C is to supply Inertia and reactive power to HVDC system which is a kind of a generator without the function of reactive power control and Inertia. Therefore, the parameters of S,C have to be determined by considering HVDC operating characteristics. The background of this paper is the determination of S.C parameters in Cheju AC network in the case of replacing current operating S,C to new S.C type.

• 전기학회논문지
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• 제64권2호
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• pp.342-348
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• 2015

In this paper, fuel cell power generation system that is being studied in recent railway field was applied to compensate for the voltage drop due to the load as driving electric vehicle. PSIM simulation program is to be used to implement the modeling of the electric railway for AC AT feeder system. For it, It was applied to the product-type single-phase PLL algorithm, step-down converter is controlled as power so as to have the fuelcell generation system. Based on it's result, a reactive power due to the catenary impedance in accordance with the current flowing is compensated as linked with fuelcell generation system which supplied the current to the power supply grid. and then its performance was confirmed that voltage compensation effect obtained at SubStation (SS), SubSectioning Post (SSP), Sectioning Post (SP).

• ETRI Journal
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• 제13권2호
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• pp.21-27
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• 1991

Effects of annealing on the dielectric properties and microstructures of thin tantalum oxide film(25nm) deposited on p-type Si substrate with rf reactive magnetron sputtering were investigated. The leakage current density was remarkably reduced from $10^-8$ to $10^-12$ A/$\mum^2$at the electric field of 2MV/cm after rapid thermal annealing(RTA) in $O_2$at $1000^{\circ}C$, while little leakage reduction was observed after furnace annealing in $O_2$ at $500^{\circ}C$. The structural changes of thin tantalum oxide film after annealing were examined using high resolution electron microscope(HREM). The results of HREM show that substantial reduction in the leakage current density after the RTA in $O_2$ can be attributed to crystallization and reoxidation of the thin amorphous tantalum oxide film.

• 대한기계학회논문집A
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• 제32권5호
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• pp.424-429
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• 2008

Surface wettability in terms of the size of the micro nano structures has been examined. To evaluate the influence of the nano structures on the contact angles, we fabricated two different kinds of structures: squarepillar-type microstructure with nano-protrusions and without nano-protrusions. Microstructure and nanostructure arrays were fabricated by deep reactive ion etching (DRIE) and reactive ion etching (RIE) processes, respectively. And plasma polymerized fluorocarbon (PPFC) was finally deposited onto the fabricated structures. Average value of the measured contact angles from microstructures with nanoprotrusions was $6.37^{\circ}$ higher than that from microstructures without nano-protrusions. This result indicates that the nano-protrusions give a crucial effect to increase the contact angle.

• Journal of Power Electronics
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• 제18권3호
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• pp.817-825
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• 2018

In this paper, a current hysteresis control with good decoupling properties for doubly-fed brushless induction machines (BDFIMs) has been proposed based on a generalized vector model. The independent control of the reactive power and speed for BDFIMs has been achieved by controlling the d-axis and the q-axis current of the control windings (CW). The proposed vector control method has been developed for the power winding (PW) flux frame. Experimental verification of a type Y180M-4 BDFIM prototype with 1/4 pole-pairs has been presented. Evidence of its good performance has been shown through experimental results.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2008년도 추계학술대회 논문집
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• pp.310-314
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• 2008

The exploitation of the wind energy resource is a rapidly growing area world-wide. The number of installed units is continuously increasing, and it is important to respect and to deal with the impact of wind turbine. This paper addresses the power quality characteristics of U57 Wind Turbine. 750kW gearless type wind turbine for low wind speed, named U57, is developed by UNISON. The power quality measurement system consists of measuring WTG output current, line-to line voltage and wind speed signal. With using measured data, power quality measurement is evaluated about maximum power, reactive power, voltage fluctuation, harmonics according to IEC 61400-21.

• 대한가정학회지
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• 제25권1호
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• pp.35-42
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• 1987

Since the 1930's, a rapid development of resin processing has contributed to making our clothing life convenient and rich. Wrinkle considered as the largest defect of cellulose fiber is generated from fixation of molecules which are divided by compression or crookedness. It can be protected by building a bridge between the molecules the joint combination of the inside of the fiber. The formaldehyde reactive resin which is used in processing resin is a chemical compound with more than 2 N-methylol or N-alkoxymethylol group and a chemical compound with N-methylol shows the property of W.W and D.P through the very complex bridge-bonding reaction under the OH group of cellulose and acid catalyst. However, if the processing is excessively carried out, resin-processed textile emits the formaldehyde when the bridge bonding agent reacts to amine type under the acid condition or the formaldehyde remains in the condition of non-reaction or the resin combinates by itself, or the methylol group of non-reactive resin is hydrolyzed due to the insufficient themomagnetic treatment.