• 한국자동차공학회논문집
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• 제23권2호
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• pp.178-184
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• 2015

According to the regulation on the environment and fuel efficiency is becoming strict, many experiments are conducted to improve efficiency and emission in internal combustion engines. LTC (Low temperature combustion) technology is a promised solution for low emissions but there are a few barriers for the commercial engine. This paper includes optimization that applies LTC method to heavy duty diesel engine. Adequate LTC was applied to low and middle load as adaptability in heavy duty diesel engine, and optimization focused on reduction of fuel consumption was proceeded at high load. Through this research, strategy for practical use of LTC was selected, and fuel consumption has improved on the condition that satisfies the emission regulation at systematic viewpoint.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 하계학술대회 논문집 A
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• pp.285-288
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• 2001

In this paper we proposed the on line volt/var control schemes of the load Tap Changer (LTC) transformer and shunt capacitor bank for distribution volt/var regulation. In the existing volt/var control of the distribution substation, the voltage of feeders and var of distribution systems is mainly controlled by the LTC transformer tap position and on/off status of the shunt capacitor. The LTC and shunt capacitor bank has discrete operation characteristics and therefore it is very difficult to control volt/var at the distribution networks within the satisfactory levels. Also there is limitation of the operation times of the LTC and shunt capacitor bank because it is affects on their functional lifetime. The proposed volt/var control algorithm determine an optimal tap position of LTC and on/off status of shunt capacitors at a distribution network with the multiple feeders. The mathematical equations of the proposed method are introduced. Simple case study was performed to verify the effectiveness of the proposed method.

• Journal of Electrical Engineering and Technology
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• 제7권3호
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• pp.320-329
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• 2012

The Load Tap Changing (LTC) transformer and Shunt Capacitor (SC) bank are major devices for voltage and reactive power control in a distribution substation. Thus, the coordination operation of a LTC transformer and a SC bank is required to achieve better voltage and reactive power compensation at a distribution substation in the same time. This paper proposes coordinate control method of LTC transformer and SC bank to achieve better voltage and reactive power compensation and operation times of these two devices in the same time. The mathematical formulations of the proposed coordinate control method are introduced. Sample case studies are shown to verify the effectiveness of the proposed coordinate control method.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회B
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• pp.3013-3018
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• 2008

Supercharging system was adopted to investigate the influence of boost pressure on operating range, brake specific fuel consumption (BSFC) and exhaust emissions by using a supercharger at low temperature diesel combustion (LTC) condition in a 5-cylinder 2.7 L direct injection diesel engine. The experimental parameters such as injection quantity, injection timing, injection pressure and exhaust gas recirculation (EGR) rate were varied to find maximum operating range. The result showed that operating range with boost was expanded up to 41.9% compared to naturally aspirated LTC condition due to increased mixing intensity. The boosted LTC engine showed low BSFC value and dramatically reduced soot emission under all operating range compared with high speed direct injection (HSDI) mode. Finally, this paper presents the boosted LTC map of emission and the strategy of improved engine operating range.

• Clinical and Experimental Pediatrics
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• 제52권6호
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• pp.680-688
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• 2009

목 적 : 류코트리엔은 천식의 병태생리에 중요한 향염증성 매개체이며, 천식이나 운동유발성 천식에서 증가되어 있다. Leukotriene C4 synthase (LTC4S)의 A(-444)C 유전자 다형성과 cysteinyl leukotriene receptor 1 (CysLTR1) T(＋927)C 유전자 다형성이 한국 소아의 천식, 아토피 천식 및 운동유발성 천식과 연관이 있는지 알아보고, 폐기능, 기관지과민성, 총IgE 치에 영향을 미치는지 알아보고자 하였다. 방 법 : 총 856명의 천식 환자와 254명의 천식이 없는 정상아를 대상으로 하여 피부반응검사, 폐기능, 메타콜린 기관지 유발검사, 총 IgE 검사를 실시하였고, 천식 환자를 아토피 천식(699명), 운동유발성 천식(277명)으로 나누어 유전자 다형성과의 연관성을 조사하였다. LTC4S A9-444)C, CysLTR1 T(＋927)C 유전자형은 PCR-restriction fragment length polymorphism 방법으로 분석하였다. 결 과 : LTC4S A(-444)C 및 CysLTR1 T(＋927)C 유전자 다형성은 천식, 아토피 천식, 운동유발성 천식과의 연관성이 없었고, 폐기능, $PC_{20}$, 총IgE에도 차이를 보이지 않았다. 아토피 천식에서 총 호산구수는 변종형 LTC4S 유전자형에서 야생형 보다 높았다. LTC4S A(-444)C와 CysLTR1 T(＋927)C의 유전자-유전자 상호 작용도 천식, 아토피 천식, 운동유발성 천식과의 연관이 없었다. 결 론 : 한국 소아 천식의 표현형, 폐기능, 기관지과민성, 총IgE 농도는 LTC4S A(-444)C와 CysLTR1 T(＋927)C 유전자 다형성, 혹은 유전자-유전자 상호작용과 연관이 없는 것으로 생각된다.

• Clinical and Experimental Pediatrics
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• 제48권7호
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• pp.766-771
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• 2005

목 적 : 류코트리엔 수용체 길항제는 천식의 병리 반응에 관여하는 cysteiny leukotriene의 생성과 작용을 억제하여 급성기 천식 증상의 치료와 천식 증상의 조절 요법에 사용할 수 있다. 본 연구에서는 소아 천식환자에서 cysteinyl leukotriene 생성에 관여하는 $LTC_4S$ 유전자 다형태와 류코트리엔 수용체 길항제인 montelukast의 임상적 효과를 조사하여 약물유전학적 연관성 유무를 알고자 하였다. 방 법 : 환자군은 경증 지속성 천식과 중등증 지속성 천식환자 161명을 대상으로 하였고, montelukast 5 mg을 하루에 한 번씩 총 8주 동안 투여하였다. $LTC_4S$ 유전자 다형태는 restriction fragment length polymorphism을 이용하여 조사하였다. 결 과 : 대조군에서 LTC4S 유전자형의 분포는 A/A, A/C, C/C가 각각 74.0%, 22.6%, 3.4%였고, 환자군에서는 A/A, A/C, C/C가 각각 70.8%, 23.6%, 5.6%였다. 두 군의 유전자형 분포는 통계적으로 유의한 차이를 보이지 않았고, $LTC_4S$ 유전자형 분포와 천식의 중증도 사이에도 유의한 차이가 없었다. 반응군에서는 경증 지속성 천식환자가 반응이 없는 군에서는 중등증 지속성 천식환자가 더 많았다. 전체 소아 천식환자군에서는 montelukast에 대한 반응군과 반응이 없는 군 사이에 $LTC_4S$ 유전자형에 따른 차이는 없었다. 경증 지속성 천식환자의 반응군에서 adenine 대립유전자를 가진 환자가 많았으나, 중등증 지속성 천식환자에서는 유전자형에 따른 반응군과 반응이 없는 군의 유의한 차이가 없었다. 결 론 : 본 연구에서 소아 경증 지속성 천식환자의 경우에는 통계적으로 adenine 대립유전자가 montelukast에 대한 임상적 효과를 예측할 수 있는 인자라고 할 수 있으나 전체 소아 천식환자에서는 $LTC_4S$ 유전자 다형태와 montelukast의 임상적 효과와의 연관성은 통계적으로 없었다.

• Nuclear Engineering and Technology
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• 제29권2호
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• pp.158-166
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• 1997

Integrated performance test of Chemical and Volume Control System was successfully performed in 1994. However, an extensive effort to correct hardware and software problems in the letdown line was required mainly due to the lack of adequate simulation code to predict the test accurately. Although the LTC computer code was used during the YGN 3'||'&'||'4 NSSS design process, the code can not satisfactorily predict the test due to it insufficient letdown line modeling. This study developed a numerical model to simulate the letdown test by modifying the current LTC code, and then verified the model by comparing with the test data. The comparison shows that the modified LTC computer code can predict the transient behavior of letdown system lese very well. Especially, the model was verified to be able to predict the "Stiction (composition of stick and friction)" phenomena which caused instantaneous fluctuations in the letdown backpressure and flowrate. Therefore, it is concluded that the modified LTC computer code with the ability of calculating the "Stiction" phenomena will be very useful for future plant design and test predictions.predictions.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2012년도 제45회 KOSCO SYMPOSIUM 초록집
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• pp.183-186
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• 2012

The characteristics of particulate matters (PM) from an exhaust gas for conventional and low temperature diesel combustion (LTC) in a compression ignition engine was experimentally investigated by the elemental, thermogravimetric analysis. Morphology of PM was also studied by the transmission electron microscopy. PM for LTC shows that it contains more volatile hydrocarbons, which can be easily evaporated than conventional regime. PM for LTC is comprised of smaller primary particles.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1998년도 추계학술대회 논문집
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• pp.41-44
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• 1998

(1-X)LTC-XHTC composites were manufactured with the variation of X in the range of 0.3 $\leq$X $\leq$0.6 and its dielectric properties were investigated. Here, LTC and HTC are PZN-BT-PT -based ceramics with quire temperature(Tc) of 100。 C-3$0^{\circ}C$, respectively. 0.6HTC-0.4LTC composite ceramics show excellent values of $\Delta$$\varepsilon$$_{r}$/$\varepsilon$[%] which were -7.1% at -2$0^{\circ}C$ and -12% at 5$0^{\circ}C$, respectively. It is thought that composite ceramics with above results can be applied to electrostrictive actuator, high voltage ceramic capacitor etc.mic capacitor etc.r etc.c.

• 한국분무공학회지
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• 제22권4호
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• pp.197-202
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• 2017

The objective of this study is to investigate the effects of low-temperature combustion (LTC) on the correlations of combustion characteristics and reduction of exhaust emissions in a small DI diesel engine with biodiesel fuel. In order to analyze the combustion, exhaust emission characteristics and distribution of nano size particles for biodiesel were investigated. In addition, to evaluate the effect of LTC on the combustion and emission characteristics, 30 and 50% of cooled-EGR rates were investigated. From these results, it revealed that the influence of LTC on the combustion characteristics showed that the ignition delay significantly increased and reduces peak heat release rate of premixed combustion by lowering reaction rate. With 50% EGR and advanced injection timing, soot and $NO_x$ emissions were simultaneously reduced.