• Journal of the Korean Institute of Gas
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• v.25 no.2
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• pp.34-41
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• 2021

In order to cope with the problems that may occur when the natural gas used in Korea becomes low in calories, the problems that may have to the domestic industrial gas equipment must be identified in advance, and based on this, countermeasures for efficient use of energy must be preceded. In this study, in order to solve the problem of deterioration of engine output performance and efficiency due to the introduction of low calorific gas when using a lean-burning natural gas engine that complies with the EURO-6 regulation, specific control plans and results based on the experiment are intended to be presented. In order to identify the improvement effect by the control variable represented by the ignition timing under the full load condition at the engine speed of 1,400 rpm and 550 Nm, 2,100 rpm, which is the engine speed at the rated operation condition, the thermal efficiency and exhaust gas characteristics were identified and optimized by changing the ignition timing for each gas fuel. In the case of pure methane, which shows the lowest value based on the torque under the full load condition, if the ignition timing is advanced by about 2 CAD from the reference ignition timing, the torque can be compensated without a large increase in NOx emission.

• Journal of Korea Entertainment Industry Association
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• v.15 no.2
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• pp.169-178
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• 2021

The Korean girl group "Kara" has suffered the trilemma of its de facto failure to debut, the crisis of team breakup, and the CEO crisis of the agency. But the group has made an outstanding achievement in the history of Korean pop music after overcoming all odds. Their success strategy has never been disclosed by insiders involved in Kara's total music projects. This study has been carried out in the analysis of the strategy to provide academic implications and to honor the contribution of the late CEO Ho-yeon Lee and Kara's key member Ha-ra Gu. Therefore, between Nov. and Dec. 2020, we conducted in-depth interviews with managers, composers, stylists and Ha-ra Gu(Only in 2019, before her death) who took part in the project. The research model is set up by combining Porter's Competitive Advantage Strategy and the music value chain model into categories of "Product Innovation Differentiation (PD)" (producing, album production, performance activities) and "Marketing Differentiation (MD)" (market targeting, image specialization, promotion and communication). The analysis showed that the PD focused on complete rediscovered harmonization and revalued members' personality and sincerity with peppy songs and dainty dances as well as emission of "bright energy" which caused healing effects instead of mimicking other star singers recklessly. In terms of MD, they selected Japan's 10-20s as their main market, increasing intimacy with fans and media with the image of cute+pretty+classy+sexy. The result suggests that Poter's differentiation can function as a meaningful strategy frame in the fostering, hit, and revival of idol groups. In addition, it reaffirmed that spontaneous and passionate activities of early-stage or celebrity fan may serve as a valid catalyst for realizing differentiation, as Kara's caller of Japanese actor Gekidan Hitori caused a strong "priming effect" that drove Kara's unexpected wonderful success in Japan.

• Korean Journal of Cognitive Science
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• v.21 no.4
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• pp.535-557
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• 2010

Researchers have shown the negative compatibility effect (NCE) consistently using arrows. However, they provided inconsistent interpretations about the reason why the NCE happens. The purpose of the present study is to test the factors suggested to be critical for the NCE including automatic inhibition, updated information and top-down control. Presented with arrays of masked prime and targets composed of colored double-headed arrows, participants demonstrated invulnerable NCE on the basis of direction of arrows in the judgment of direction with corresponding hands (Experiment 1), with reverse-mapping hands (Experiment 2) and even in the color-judgment task (Experiment 3). These results imply that the main sources of NCE might be perceptual dominance and inherent properties of stimuli and responses; this contrasts with previously proposed explanations.

• Phonetics and Speech Sciences
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• v.1 no.2
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• pp.63-73
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• 2009

The present study was conducted to explore how the processing of lexical ambiguity between homonymy and polysemy differs from each other, and whether the representation of mental lexicon was separated from each lexical ambiguity by a semantic priming paradigm. Homonymy (M1 means the literal meaning of '사과', i.e. apple and M2 means another literal meaning of '사과', i.e. apologize) was used in Experiment I, and polysemy (M2 means the literal meaning of '바람', i.e. wind and M2 means the figurative meaning of '바람', i.e. wanton) was used in Experiment 2. The results of both experiments showed that a significant semantic priming effect occurs regardless of the type of ambiguities (homonymy and polysemy) and the difference of their semantic processes. However, the semantic priming effect for polysemy was larger than that for homonymy. This result supports the hypothesis that the semantic process of homonymy is different from that of polysemy.

• Journal of the korean Society of Automotive Engineers
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• v.11 no.5
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• pp.55-64
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• 1989

The effect of discharge have been investigated for condition of spark in a multiple spark ignition engine, as the spark duration, capacitive and inductive discharge energy were calculated for condition of spark by ignition wave and energy formula. The useful portion of spark discharge is divided into capacitance portion and inductance portion. It was found that capacitive discharge energy and spark duration were increased according to increasing number of spark, and inductive discharge energy was increased according to increasing spark interval. Therefore engine torque was increase and lean misfire limit was extended comparing with the standard ignition system. It found that spark energy was discharged within ignition delay period availability acted on the formation and growth of flame kernel, and total spark energy was increased according to increasing number of spark times, but discharged spark energy after ignition delay became unavailable energy. And the capacitive discharge energy has the dominant effect for stoichiomeric or not very rich air-fuel mixture but inductive discharge energy has the dominant effect for lean air-fuel mixture.

• 전기의세계
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• v.33 no.10
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• pp.625-630
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• 1984

압전변압기는 압전효과를 응용한 점화소자와 필터의 중간적인 존재로서 그 두 기능을 합친 것과 같은 특성을 가지며, 전기적 에너지가 기계적 에너지로 변환된 후 다시 전기적 에너지로 환원되는 과정을 통하여 고전압을 얻는 변압기이다. 이러한 변압기는 자속을 응용하는 일반적인 변압기와는 달리, 유전체인 압전세라믹소자의 압전현상과 공진현상을 응용하므로 주파수대역이 좁고 취급되는 전류가 적다는 단점이 있으나, 구조가 간단하고, 제작이 용이하며, 소형이고, 손실이 적은 장점들이 있어서 특히 고전압고전류원을 필요로하는 음극선관, 음이온발생기, 집진기, 전자복사기, 도장기 등에 이용되고 있으며, 최근에는 다른 분야에도 응용이 시도되고 있다. 여기서는 기존의 압전변압기 중에서 가장 많이 쓰이고 있는 Rosen형(또는 transverse형)압전변압기의 구조와 특성들을 간단히 기술하고, 새로운 형태인 적층형 압전변압기에 관하여 소개하고자 한다.

• 유체기계공업학회:학술대회논문집
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• 2000.12a
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• pp.318-324
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• 2000

액체로켓인 KSR-III는 점화시 및 연소실 압력의 이상 저하시 추진제가 지나치게 많이 공급되는 것을 막기 위하여 케비테이션 벤튜리를 사용한다. 본 연구에서는 Fluent가 제공하는 케비테이션 모형을 사용하여 케비테이션 벤튜리 내부의 공동 발생과 이에 따른 유량제어 현상을 해석하였다. 케비테이션 모형은 공동의 붕괴를 효과적으로 예측하지 못하는 단점이 있지만 벤튜리를 통과하는 유량은 공동이 발생하는 위치에서 유효 유로 감소에 의하여 제한되므로 유량제어 현상을 성공적으로 관찰할 수 있었다. 결과로서 벤튜리 상류의 압력이 일정하게 유지될 때 하류의 압력 변동에 대하여 유량이 변화하지 않음을 확인하였다. 상류의 압력이 24.1bar로 일정하게 유지되고 벤튜리에서 압력차이가 3bar 이하일 때 공동은 발생하지 않았다. 압력차가 6bar 이상일 때 공동이 발생하며 (압력차 6bar인 경우와 비교하여) 9bar, 12bar의 압력차에 대한 유량 증가는 각각 $5\%,\;7\%$에 그쳐 주어진 작동조건에서 벤튜리로 유량제어가 가능하였다.

• Journal of Power System Engineering
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• v.14 no.2
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• pp.12-15
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• 2010

It is requested to shorten the starting duration for idle stop function equipped cars without harmful effects on the environment. Higher cranking speeds can be achieved with high torque starter. The object of this study is to develope the high torque starter and evaluate its effect on the exhaust emissions. The test was conducted on a 1.5 L, 4-cylinder, 16 valve, multipoint-port-fuel-injection gasoline engine. Engine out emissions such as HC, CO, $CO_2$, and the excess air ratios, lambda were measured using MEXA-554JK. The result showed that a high torque starter, HTS-II shortened the starting duration and reduced engine out emissions of HC, CO and improved starting performance with larger excess air ratio than that of the original starter, Org. S and a high torque starter, HTS-I.

• Journal of the korean Society of Automotive Engineers
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• v.8 no.2
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• pp.31-42
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• 1986

The prediction of performance, exhaust emissions and EGR effect is made by the SI engine cycle simulation. In this simulation several models are employed - two zome, thermodynamic combustion, mass fraction burned, heat transfer, chemical equilibrium, chemical kinetics for NOx, laminar flame speed for ignition delay. The chemical species in burned gas considered are 13 species-CO$_{2}$, CO, $O_{2}$, H$_{2}$O, H$_{2}$,OH, H, O, N$_{2}$, NO$_{2}$, N, Ar - and the cylinder pressure, burned and unburned zone temperature and composition of gas are calculated at each crank angle through the compression, ignition delay, combustion and expansion process. To check the validity of the model, experimental study is done for measuring emissions, combustion pressure and engine output. The predicted values for pressure and emissions show qualitative agreement with the measured data and the EGR effect also shows similar tendency.

• Journal of Energy Engineering
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• v.3 no.1
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• pp.62-69
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• 1994

화염중에 존재하는 이온 및 전자의 전기적 성질을 이용하여 연소실내의 화염전파속도를 파악하기 위해 실린더 헤드에 이온 프로브를 삽입하여 천연가스 및 가솔린의 화염전파속도를 측정하였다. 본 연구에 이용된 이온전류장치 설계에 의한 방법은 광학적 측정 장비에 비해 간단하며 쉽게 측정할 수 있고 가격도 저렴하고 응답성도 우수하였다. 이온 프로브의 제작과 신호처리에 관한 기초적인 지식을 얻었으며 천연가스 및 가솔린의 연소시 연소압력의 상승지점과 이온발생지점이 일관성있게 나타났다. 기관회전수의 증가에 따라서 연소실내의 화염전파속도가 증가했으며 같은 연소조건이라고 할 수 있는 동일 기관회전수, 당량비의 조건에서 점화시간에 대한 화염전파속도를 비교해 보면 메탄의 경우가 이론치보다 6 ms∼9 ms 정도 늦었다. 또한, 메탄가스 및 가솔린에 대해 이온 전류강도 및 화염 도달시간을 측정하였으며 연소실 벽면에서는 열전달에 의한 냉각효과로인해 화염 전파속도 및 이온농도가 감소했다.