• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.11a
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• pp.47-48
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• 2006

Carbon nanotubes (CNTs)-doped homogeneously aligned nematic liquid crystal (LC) cells driven by in-plane field were fabricated and their electro-optic characteristics were investigated. Effective cell retardation values in an absence of an electric field between doped and undoped LC were the same each other. In the presence of an electric field, however, measured effective cell retardation value was smaller in the CNT-doped cell than in the undoped cell so that the transmittance was slightly smaller in the CNT-doped cell than in the undoped cell. In addition, the CNT-doped cell exhibited slight increase in driving voltage and decrease in response time compared to the undoped cell. The CNT effects on electro-optic characteristics of the cell were discussed.

• Journal of Hydrogen and New Energy
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• v.16 no.4
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• pp.364-371
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• 2005

Fuel cell systems(FCS) have a financial and environmental advantage by providing electricity at a high efficiency and useful heat. For use in a residence, a polymer electrolyte fuel cell system(PEFCS) with a battery pack and a hot water storage tank has been modelled and simulated. The system is operated without connection to grid line. Its electric conversion efficiency and heat recovery performance are highly dependent on operation strategies and also on the seasonal thermal and electric load pattern. The output of the fuel cell is controlled stepwise as a function of the state of the battery and/or the storage water tank. In this study various operation strategies for cogeneration fuel cell systems are investigated. Average fuel saving rates at different seasons are calculated to find proper load management strategy. The scheme can be used to determine the optimal operating strategies of PEFCS for residential and building applications.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.5
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• pp.1055-1063
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• 2013

CTL cell that is one of the standard electromagnetic generation equipment can measure the characteristic of the electromagnetic susceptibility and the electromagnetic interference. In case of being input the same magnitude signal with the phase difference of 0o or the phase difference of 180o at two input ports of CTL cell to be the fundamental resonant frequency(TE011) of 2.20GHz, the characteristics of the electric field and the magnetic field at the uniform area were measured. And, it measured the electric field characteristic due to the variation of the input power, the test position and the input frequency under the dominant E-field and the dominant H-field of CTL cell. Using these mesuremed data, it examined the operation characteristic and the available frequency band of CTL cell.

• 한국신재생에너지학회:학술대회논문집
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• 2006.11a
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• pp.417-420
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• 2006

FCEV uses electric energy generated from the reaction between Hydrogen and Oxygen in fuel cell stack as driving force. As fossil fuels are exhausted, fuel cell is regarded as a potent substitute for next generation energy source, and thus, most of car-makers make every efforts to develop fuel cell electric vehicle (FCEV). In addition, fuel cell is also beneficial in aspect of environment, because only clean water is produced during chemical reaction process instead of harmful exhausted gas. Generally, Hydrogen is supplied from high-pressured fuel tank, and air blower (or compressor) supplies Oxygen by pressurizing ambient air. Air blower which is driven by high speed motor consumes about $7{\sim}8%$ of energy generated from fuel cell stack. Therefore, the efficiency of an air blower is directly linked with the overall performance of FCEV. This study will present developing process of an air blower and its consisting parts respectively.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.07b
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• pp.953-956
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• 2002

The electro-optical (EO) performances of a multidomain vertical-alignment (MVA) cell on a homeotropic photopolymer have been investigated. In the absence of an electric field, the MVA cell achieved black state as LC alignment is homeotropic. An electric field created by interdigitated electrodes and rib made after photolithograph using the photopolymer on both substrates causes a director deformation of a multidomain type. Good voltage-transmittance curves for a MVA cell on the homeotropic photopolymer were observed. Also, the stable response time of MVA cell on the homeotropic photopolymer can be achieved.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.54 no.12
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• pp.713-715
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• 2005

The work in this paper presents development of fuzzy logic-based energy management strategy for a fuel cell hybrid electric vehicle. In order for the fuel cell system to overcome the inherent limitation such as slow response time and low fuel economy especially at the low power region, the battery system has come to compensate for the fuel cell system. This type of hybrid configuration has many advantages, however, the energy management strategy between power sources is essentially required. For the optimal power distribution between the fuel cell system and the battery system, a fuzzy logic-based energy management strategy is proposed. In order to show the validity and the robustness of suggested strategy, some simulations are performed for the standard drive cycles.

• 한국신재생에너지학회:학술대회논문집
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• 2008.10a
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• pp.47-50
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• 2008

The sub-zero cold is a major environmental consideration for the operational readiness of FCEVs because fuel cells produce water and utilize wet air with varying water content to generate electricity. Typical fuel cells thus have a fatal flaw in freezing conditions at startup. This drawback becomes more serious with the outsourced fuel cell that is entirely water-based for its internal humidification. In this background, the HMC's self-designed fuel cell was developed as an alternative and was employed in the Tucson-based FCEV in 2006 demonstrating its good cold-startup characteristics. The cold-startup capacity of the vehicle was validated through tests in the cold chamber and on the road, resulting in 50% stack power achieved in 250 seconds at $-15^{\circ}C$.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.7
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• pp.1259-1264
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• 2010

This paper was researched about effectiveness of the electrochemical cell which is composed of the sea water and the Cu/Zn electrode. The electric potential difference between copper and zinc finally reached 0.51 volts. Short current decreased with time. It might depend on the electromotive force decreasing. Confirmed the load resistance and electrode affect in electromotive force and electric current. The resistance which shows a maximum output power was 20[$\Omega$], and the maximum output power from this resistance was evaluated as 0.736mW. In order to calculate the energy which creates from electrochemical cell, charging voltage of the capacitor with various capacitance was investigated. It was found that energy harvesting possibility of the cell which is made of a sea water electrolyte and the copper/the zinc.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.16 no.3
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• pp.219-223
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• 2003

The electro-optical (EO) performances of a multidomain verticial-alignment (MYA) cell on a homeotropic photopolymer have been investigated. In the absence of an electric field, the WVA cell achieved black state as LC alignment is homeotropic An electric field created by interdigitated electrodes and rib made after photolithograph using the photopolymer on both substrates causes a director deformation of a multidomain type. Good voltage transmittance curves for a MVA cell on the homeotropic photopolymer were observed. Also, the stable response time of MYA cell on the homeotropic photopolymer can be achieved.

• Journal of Electrochemical Science and Technology
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• v.13 no.3
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• pp.369-376
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• 2022

In this study, the stability of an anion exchange membrane water electrolyzer (AEMWE) cell was evaluated in an on-off cycling operation with respect to an applied electric bias, i.e., a current density of 500 mA cm^-2, and an open circuit. The ohmic and polarization resistances of the system were monitored during operation (~800 h) using electrochemical impedance spectra. Specific consideration was given to the ohmic resistance of the cell, especially that of the membrane under on-off cycling conditions, by consistently feeding the cell with KOH solution. Owing to an excess feed solution, a momentary increase in the polarization resistance was observed immediately after the open-circuit. The excess feed solution was mostly recovered by subjecting the cell to the applied electric bias. Stability tests on the AEMWE cell under on-off cycling with continuous feeding even under an open circuit can guarantee long-term stability by avoiding an irreversible increase in ohmic and polarization resistances.