• 한국전기화학회:학술대회논문집
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• 2002.04a
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• pp.40-40
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• 2002

• 한국전기화학회:학술대회논문집
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• 2003.04a
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• pp.59-59
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• 2003

• 한국전기화학회:학술대회논문집
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• 2003.04a
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• pp.66-66
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• 2003

• Korean Journal of Materials Research
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• v.21 no.8
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• pp.468-475
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• 2011

[ $LaMeO_3$ ](Me = Cr, Co) powders were prepared using the polymeric precursor method. The effects of the chelating agent and the polymeric additive on the synthesis of the $LaMeO_3$ perovskite were studied. The samples were synthesized using ethylene glycol (EG) as the solvent, acetyl acetone (AcAc) as the chelating agent, and polyvinylpyrrolidone (PVP) as the polymer additive. The thermal decomposition behavior of the precursor powder was characterized using a thermal analysis (TG-DTA). The crystallization and particle sizes of the $LaMeO_3$ powders were investigated via powder X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), and particle size analyzer, respectively. The as-prepared precursor primarily has $LaMeO_3$ at the optimum condition, i.e. for a molar ratio of both metal-source (a : a) : EG (80a : 80a) : AcAc (8a) inclusive of 1 wt% PVP. When the as-prepared precursor was calcined at $700^{\circ}C$, only a single phase was observed to correspond with the orthorhombic structure of $LaCrO_3$ and the rhombohedral structure of $LaCoO_3$. A solid-electrolyte impedance-metric sensor device composed of $Li_{1.5}Al_{0.5}Ti_{1.5}(PO_4)_3$ as a transducer and $LaMeO_3$ as a receptor has been systematically investigated for the detection of NOx in the range of 20 to 250 ppm at $400^{\circ}C$. The sensor responses were able to divide the component between resistance and capacitance. The impedance-metric sensor for the NO showed higher sensitivity compared with $NO_2$. The responses of the impedance-metric sensor device showed dependence on each value of the NOx concentration.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.14 no.8
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• pp.663-669
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• 2001

Spinel LiM $n_2$ $O_4$ and LiM $n_{1.9}$M $g_{0.1}$ $O_4$ power was synthesized with solid-state method by calcining the mixture of LiOH.$H_2O$, Mn $O_2$ and MgO at 80$0^{\circ}C$ for 36 h in an air atmosphere. To investigate the effect of temperature on he cycle performance of cathode material during cycling, charge-discharge experiments and ac impedance measurement were performed. Initial discharge capacity was gradually increased with the increase of charge-discharge temperature. Discharge capacity at high temperature was suddenly decreased during cycling. On the other hand, discharge capacity at low temperature was almost constant during cycling. It confirmed that Mn dissolution is serious at high temperature than at low temperature. LiM $n_2$ $O_4$ and LiM $n_{1.9}$M $g_{0.1}$ $O_4$ showed the best capacity and stability at room temperature.ure.ure.

• Applied Chemistry for Engineering
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• v.29 no.5
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• pp.549-555
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• 2018

In this study, the electrochemical properties of nano-Pb/activated carbon (nano-Pb/AC) composites and electrolyte additives were examined to improve the performance of ultra batteries. Physical properties of the prepared nano-Pb/AC composites were analyzed using FE-SEM, TEM, XPS and BET. The electrochemical performances of ultra batteries were performed by cycle, rate performance and impedance tests. The cycling performance of nano-Pb/AC (Pb : 9 wt%) coated ultra battery increased by 150% with respect to the lead acid one, and the discharge specific capacity increased by 119-122% for 1-5 C rate tests. As a result of the impedance test, it was confirmed that the internal resistance decreased as the nano lead content increased. The cycle performance of the ultra battery containing 0.45 vol% electrolyte additives showed 140% longer than that of no electrolyte additives.

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.1617-1618
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• 2015

This paper analyzed catenary impedance characteristics of relays installed in substation and sectioning post to protect power feeding circuit in the extended power feeding conditions. For this, we modelled AT feeding system using PSCAD/EMTDC and calculated catenary impedance. The relay installed in substation calculated catenary impedance of the extended power feeding area adding catenary impedance of self protection zone. But, the relay installed in sectioning post calculated catenary impedance of the only protection area. Therefore, we confirmed that the more reliable protection way can be utilized using the relay installed in sectioning post.

• Proceedings of the KIEE Conference
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• 1998.07a
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• pp.387-389
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• 1998

For the continuous and exact measurement of load impedance of AC power system on the electric railway, this paper presents a method to show the load area to resistance(R)-reactance(X) plane of impedance plane. The load area is presented in terms of impedance which is in the ratio of voltage and current continuously measured and impedance plane indicates the protection area of fault locator. The proposed method is verified its reasonability by computer simulation, and using this method we will develop the power system impedance analyser which is available actual application.

• Journal of Power Electronics
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• v.9 no.3
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• pp.418-429
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• 2009

In this paper an optimal damped input filter is designed based on a Genetic Algorithm (GA) for an electrolytic capacitor-less AC-AC converter. Sufficient passive damping and minimum losses in passive damping elements, minimization of the filter output impedance at the filter cut-off frequency, minimization of the DC-link voltage and input current fluctuations, and minimization of the filter costs are the main objectives in the multi-objective optimization of the input filter. The proposed filter has been validated experimentally using an induction motor drive system employing an electrolytic capacitor-less AC-AC converter.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.10
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• pp.1458-1464
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• 2013

This paper proposed a new real time catenary impedance estimation technique using synchronized power data from the measured data of operating vehicle and substation for catenary protective relay and fault locator setting. This paper presented estimation equation of catenary impedance using synchronized power data between substation and vehicle of AT feeding system for the performance verification of the proposed technique. Also AC feeding system is modeled through power analysis program and performance was verified through simulation according to various load changes. We verified that average 2.38%(distance equivalent 23.8 m) error appeared between the proposed estimation equation of catenary impedance and power analysis program simulation output in no connection double track system between up track and down track. Furthermore, We confirmed that estimation error is bigger depending on the increasing the distance from substation and vehicle impedance using only using vehicle current when calculating vehicle impedance in connection double track system between up track and down track. But, We confirmed that the proposed technique estimated accurately catenary impedance regardless of vehicle impedance and distance from substation.