• Proceedings of the KIPE Conference
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• 2017.07a
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• pp.158-159
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• 2017

본 논문에서는 매입형 영구자석 동기전동기를 위치센서 없이 기동하기 위해 회전자의 초기 위치를 추정하는 방법을 제안한다. 제안된 방법은 자기 인덕턴스의 포화현상에 따른 고정자 전류를 해석하고 최소자승법을 통해 회전자의 초기 위치를 추정한다. 전 구간에서 회전자의 초기 위치와 극성을 정확하게 알아낼 수 있어 돌극성 때문에 나타나는 릴럭턴스 토크를 효과적으로 사용할 수 있다. 또한, 전동기 정수에 영향을 받지 않으므로 다양한 전동기 구동 시스템에 적용할 수 있으며, 추가적인 하드웨어가 필요하지 않아 경제적이다. 제안하는 방법의 유효성과 우수성은 시뮬레이션을 통해 검증한다.

• Journal of the Korean Chemical Society
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• v.37 no.3
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• pp.335-343
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• 1993

The maximum absorption wavelengths of charge-transfer complexes of naphthalene, ${\alpha}-and{\beta}-methyl$ naphthalene and 1,2-, 2,3-and 2,6-dimethyl naphthalene with chloranil have been measured with a UV spectrophotometer in ethylene chloride, methylene chloride, and chloroform at 10, 15, 20, and 25$^{\circ}C$. This absorption band was interpreted as the charge transfer band of a 1 : 1 molecular complex, and the maximum absorption wavelength was changed as a function of solvent and temperature. Their formation constants (K$_f$) were decreased with the polarity of solvent and the increase of temperature. Thus, the influences of solvent and temperature on the formation constant have been discussed as consideration of thermodynamic properties, and the electronic and steric effects of electron donors on formation constant have been also discussed.

• Proceedings of the Korea Information Processing Society Conference
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• 2018.05a
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• pp.267-270
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• 2018

구제역으로 인하여 국내 축산업계 및 관련 산업분야는 매년 막대한 피해를 입고 있다. 구제역과 관련한 다양한 학술적 연구들이 현재 진행되고는 있으나, 구제역의 발병에 따른 사회적 파급효과에 관한 공학적 분석 연구는 매우 제한적이다. 본 연구에서는 구제역에 관한 일반 시민들의 감성적 반응을 텍스트 마이닝 방법론을 사용하여 분석하는 체계적인 방법론을 제안한다. 제안하는 시스템은 먼저, 트위터에 게시된 트윗 중 구제역과 관련된 데이터를 수집한 후, 감성사전을 기반으로 극성탐지 과정을 거친다. 둘째, 토픽 모델링의 대표적인 기법 중 하나인 LDA를 활용하여 트윗으로 부터 키워드들을 추출하고, 추출된 키워드들로부터 극성별 동시출현 키워드 네트워크를 구성한다. 셋째, 키워드 네트워크을 통해 각 구간별 구제역의 사회적 파급효과를 분석한다. 사례 분석으로써, 2010년 7월부터 2011년 12월까지 국내에서 발생한 구제역에 관한 일반 시민들의 감성적 변화를 분석하였다.

• Proceedings of the KAIS Fall Conference
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• 2008.11a
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• pp.267-269
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• 2008

본 연구는 이온주입(Ion Implanter)장비의 성능향상과 재현성 있는 Source Head를 개발하기 위한 방법이다. 본 개발은 이온주입설비가 가지고 있는 Cathode 열전자를 이용하여 원자라는 Source Positive의 극성을 생성하여 보다 높은 이온화를 발생하여 많은 시간 동안 사용 가능하도록 하였다. 기존에는 Gas의 손실이 많아 원자의 이온화에 대한 열전자의 소모성을 증가하는 원인을 제공하였으나, 본 개발에서는 원자의 유입방식을 공중 분산방식으로 적용함으로써 열전자의 손실로 발생하는 부분을 억제하는 효과와 Arc Chamber의 압력을 낮게 가지고 갈 수 있고 Chamber의 오염을 억제하는 효과를 얻을 수 있었다.

• Electrical & Electronic Materials
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• v.8 no.5
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• pp.601-605
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• 1995

This study was concerned, after the oxide films(50 [.angs.]) were grown in a furnace and the MOS capacitor fabricated, with experimental comparison and verification about the Interference Effect of Electronic Waves in the ultra thin oxide/silicon interface. The average error was about 0.8404[%] in n'gate/p-sub and about 0.2991[%] in p$^{+}$gate/p-sub. Therefore, it was predicted that the Interference Effect of Electronic Waves can overcome somewhat according to the gate polarity.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.27 no.6
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• pp.696-703
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• 1994

To utilize waste of squid effectively, antioxidant properities of squid viscera were elucidated. Major fatty acids of total lipid, neutral lipid and phospholipid were $C_{16:0},\;C_{18:1}\;and\;C_{20:5},\;C_{22:6}$ and consisted $63{\sim}71\%$ of total fatty acids. Total lipid did not show significant antioxidant activity when added to the fish oil at the concentration below $5.0\%$, Antioxidant activity of hexane extract was lower than total lipid or tetra carbon chloride-methanol($CCl_4-MeOH$) extract. Extracts with $CCl_4-MeOH$ exerted higher antioxidant activity as the methanol ratio was increased, suggesting that polar lipid plays and important role.

• Korean Journal of Food Science and Technology
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• v.27 no.1
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• pp.80-85
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• 1995

After solvent extraction of 28 domestic cultivated medicinal plants using methylene chloride, 1000ppm of extracts were added to linoleic acid to compare antioxidative activities. Although their magnitude was somewhat different, all extracts showed the antioxidative activities. Antioxidative activity of Scutellariae baicalensis extract was similar to that of BHA. Antioxidative activity of Paeonia moutan and Liriope platyphylla extracts was lower than that of Scutellariae baicalensis. When Scutellariae baicalensis was extracted with 9 solvents which have a different polarity, the extraction yield and antioxidative activity generally increased with increasing polarity. The nitrite-scavenging effects, electron donating abilities(EDA) and anti-complementary activities were determined.

• Elastomers and Composites
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• v.41 no.2
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• pp.116-124
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• 2006

Cloud-point data to $160^{\circ}C$ and 1,000 bar are presented with poly(ethylene-co-15.3 mole% octene) copolymers ($PEO_{15}$) in pure 1-octene and mixtures of ethylene - 1-octene. The cloud-point curves for $PEO_{15}$ - ethylene - 1-octene mixture dramatically increase in pressure to as high as 1,000 bar with an increasing ethylene concentration. At ethylene concentrations less than 18 wt%, the ternary mixture has bubble- and cloud-point curves. As the ethylene concentration of the ternary mixture increases, the bubble-point curve and the single-phase region reduce. The reduction in the single phase region with increasing ethylene concentrations is the result of reduced dispersion interactions between $PEO_{15}$ and the mixed solvent. The single-phase region decreases with increasing temperatures when ethylene concentrations are lower than 36 wt%, whereas the single-phase region increases with temperatures at ethylene concentrations greater than 50 wt%. At ethylene concentrations greater than 50 wt% the effect of the polar interactions of the mixed solvent, which is unfavorable to dissolve PEO, is greater than the effect of the density of the mixed solvent. Therefore, the cloud-point pressures increase with a decreasing temperature. However, at ethylene concentrations less than 50 wt%, the cloud-point pressures decrease with temperature, because the effect of the polar interactions is less than the density effect.

• Journal of the Korean Chemical Society
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• v.37 no.8
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• pp.695-701
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• 1993

Rate constants of solvolysis of 2-thiophenesulfonyl chloride were determined in aqueous binary mixtures with methanol, ethanol, acetone in water and in methanol. These data are interpreted using the equation of Grunwald-Winstein and Kivinen relationship. Also, kinetic solvent isotope effects in water and in methanol and product selectivities in alcohol-water mixtures were determined. Kinetic solvent isotope effect for hydrolysis of 2-thiopenesulfonyl chloride was 2.24 and 1.47 for methanol and water, respectively. Selectivity values for formation of ester relative to acid in ethanol-water mixtures show maximum S value. From kinetic solvent isotope effect in methanol and water, selectivity data in aqueous alcoholic solvents and solvent effects, it is proposed that the reaction channel favoured in low polarity solvents is general-base catalysis and/or is possibly addition elimination (S$_A$N) reaction pathway and in high polarity solvents iS S$_N$2 reaction mechanism.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.23 no.8
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• pp.67-73
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• 2009

The magnetic saliency effect in surface-mounted permanent-magnet (SMPM) motors on the torque control at high speeds is first presented and analyzed in this paper. The d- and q- axes impedance are measured by proposed State-Filter. Measurement of the d- and q- axes impedance difference is performed to prove the existence of the magnetic saliency. Then, the saliency effects on the torque control performance in the flux weakening region are discussed. Based on the developed motor modeling with the reluctance torque, the proposed control adjusts the d- and q-axis current toward the operating point to track the commanded torque. The feasibility of the presented idea is verified by experimental results on a commercial 600[W] SMPM motor.