• Journal of the Korean Society of Marine Environment & Safety
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• v.19 no.5
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• pp.525-530
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• 2013

In this study, the generator engine of training ship M/S "HAE RIM" of Kunsan National University which is being operated for 20 years was used in the experiment. The experiment was carried out under the engine speed of 1200rpm, then the load was varied 30 kW intervals from 0 to 90 kW and the injection timing was varied $2^{\circ}$CA intervals from BTDC $19^{\circ}$ to $23^{\circ}$CA. In the case of advancing fuel injection timing from BTDC $21^{\circ}$CA to $23^{\circ}$CA, specific fuel consumption is decreased by 1.37%, NOx is increased by 11.59 %, soot is decreased by 23.5 % and $SO_2$ is decreased by 2.8 %. Accoring to the analysis of effects of fuel injection timing on combustion & exhaust emissions characteristics on an old marine diesel engine, it is proved that the optimum fuel injection timing is BTDC $23^{\circ}$ which is $2^{\circ}$ faster than that of original injection timing.

• Journal of the Korean Wood Science and Technology
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• v.44 no.3
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• pp.360-369
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• 2016

In this study, sequential leaching and wet torrefaction were performed to improve the fuel characteristics of empty fruit bunch (EFB). Leaching was carried out at $25{\sim}90^{\circ}C$ for 5~30 min. The highest ash removal efficiency of 55.99% was achieved when leaching was performed at $90^{\circ}C$ for 10 min. The ash removal efficiency was dependent more on leaching temperature than time. Wet torrefaction was carried out at $180{\sim}200^{\circ}C$ for 5~40 min, following the leaching. Most of the inorganic compounds were removed at removal efficiencies of 41.05~63.58% during sequential leaching and wet torrefaction, while silica remained in the biomass. Chloride, calcium, magnesium, and phosphorus showed more than 80% removal efficiencies. The calorific value of EFB increased to 7.96% (4730 kcal/kg) in comparison to the raw material (4390 kcal/kg) when wet torrefaction was performed at $200^{\circ}C$ for 40 min following leaching.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.9 no.1
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• pp.74-78
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• 1976

In this paper, the author experimented, by using the C. F. R. engine, how the functions of engine is changed when the compression ratio is raised. In the process of these experiments, by using three kinds of fuel, such as cetane number 95, 61, 33, and set the engine speed as 900 r. p. m., fuel injection time is determined as B. T. D. C. $13^{\circ}$. As the result of test, the best compression ratio is disernable in proportion to each fuel, and acknowledges that if the higher compression ratio were to exist other than the above one, efficiency of heat gets rather lower, and that the maximum output of engine decreases. Andthe best compression ratio changed according to supply calorie per each hour, and this change is more remarkable in the fuel of low cetane number. Consequently, the best compression ratio cannot be regardless of output in the fuel of low cetane number.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.11a
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• pp.763-768
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• 2011

The effects of $CO_2$-dilution on combustion instability were studied in order to apply biogas in a dual lean premixed gas turbine combustor on a real-scale dual lean premixed burner head which is originally developed for Natural Gas fuel. Combustion instability is reduced by $CO_2$ dilution effect according to the result of dynamic pressure signal and phase-resolved $OH^*$ images. The reason for this is that dilution of $CO_2$ reduces heat release perturbation and increases flame volume due to reduction of the flame speed and expansion of flame surface.

• Membrane Journal
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• v.27 no.2
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• pp.182-188
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• 2017

Sulfonated poly(arylene ether sulfone) (SPAES)-3-mercaptopropyl silica gel (3MPTSG) composite membranes with improved oxidative stability were prepared for polymer electrolyte fuel cell application. It has been reported that ether part of main chain of aromatic hydrocarbon based membranes were weak to radical attack to decrease membrane durability. In this study, the hydrophilic inorganic particles were introduced by minimizing a decrease in ion conductivity and increasing an oxidative stability. The composite membranes were investigated in terms of ionic conductivity, ion exchange capacity (IEC), FT-IR, TGA and contact angle, etc. As a result, increasing amount of the 3MPTSG resulted in decrease in proton conductivities and water uptakes at 100% R.H. but enhanced thermal and oxidative stabilities.

• Proceedings of the KIEE Conference
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• 1987.07b
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• pp.1203-1205
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• 1987

가솔린 엔진용 전자 제어 에뮬레이션 시스템은 엔진의 운전 상태를 알려 주는 각종 센서로 감지한 정보를 A/D변환기를 통해 마이크로프로세서에 입력시키고, 이 정보를 이용하여 운전 상태를 분석한 후 엔진이 푤요로 하는 연료량, 점화시기, 배기가스의 재순환량, 공회전수 등을 전자적으로 제어하여 엔진의 최적제어를 실현시킴으로서 연료소비율 및 배기가스 중 공해물질 함량을 감소시키기 위한 장치이다.

• Journal of Advanced Marine Engineering and Technology
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• v.35 no.4
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• pp.406-413
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• 2011

Recently the fuel cell has been spotlighted as a technology to reduce greenhouse gases emission from a ship. In this research, internal reforming 500kW solid oxide fuel cell stacks fueled by methane for a ship were developed. Characteristics of power and efficiency depending on the number of cells in the stack, hydrogen conversion ratio, and active area of the cell are evaluated. Also the effects of air and methane supplying conditions on performance are analyzed. As a result, as the number of cells, hydrogen conversion ratio, active area of the cell, or supplied air flow rate increase, the stack power and efficiency increase. When the methane flow rate increases, the power increases. However the efficiency decreases. In addition, the case at the current of 976.4 A, voltage of 529.1 V, with corresponding power of 516.6 kW shows that the efficiency of fuel cell stack is 42.91%.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.5
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• pp.700-707
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• 2017

In the international natural gas market, natural gas has markedly low calories. The domestic calories standard of natural gas was changed and the performance and efficiency of many industrial machines using natural gas were affected because of low caloric natural gas. Therefore, in this study, a dual fuel engine fueled with natural gas and diesel was tested to examine the effects of the CNG substitution rate on the combustion characteristics, such as thermal efficiency, COVimep and heat release rate. The CNG substitution rate was defined as the ratio of CNG instead of diesel, which was calculated as the total energy. The conditions of the tested engine were fixed $1800rpm/500N{\cdot}m$. In addition, diesel fuel was injected at $16^{\circ}CA$ BTDC and the fuel pressure was fixed at 85 MPa; the lower heating value of CNG was $10,400kcal/Nm^3$. The results of the engine test showed that the amount of diesel fuel was changed according to the CNG substitution rate. Therefore, when the substitution rate was increased, the amount of diesel fuel was decreased, which affected the energy for ignition. In addition, the ignition delay duration was increased, which affected the thermal efficiency and torque. On the other hand, the COVimep was less than 5% and a stable combustion state of the engine was shown.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.08a
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• pp.296-296
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• 2010

ICRF 시스템을 이용한 방전세정인 ICWC(Ion Cyclotron Wall Cleaning)는 ITER와 DEMO 같은 초전도 자석을 이용하는 토카막에서 토카막 shot 중간에 자장을 낮추지 않고 바로 방전 세정을 할 수 있는 방법이다. 토카막에서 방전세정은 탄소나 산소 화합물과 같은 불순물을 제거하여 방사에 의한 플라즈마 냉각을 막고 토카막 초기 start-up시 진공 챔버 벽면으로부터 의도하지 않은 연료주입을 제거하는 역할을 한다. 본 연구에서는 ICWC 방전 세정 최적화를 위해 플라즈마의 불순물 제거 특성을 수소 유량의 크기와 ICRF 펄스의 duty ratio를 바꿔가면서 관찰하였다. ICRF 전력은 44.2 MHz에서 20-50 kW 가 입사되었으며 자장은 3 T에서 고정되었다. 운전압력은 $10^{-4}$ mbar 정도이다. 헬륨의 유량을 400 sccm으로 고정한 후 수소의 유량을 40 sccm에서 160 sccm까지 증가시켜가면서 제거율을 관측하였다. 그 결과 수소 유량의 증가에 따라 제거율이 증가하는 불순물과 오히려 감소하는 불순물이 있음이 관측되었다. 제거율이 증가되는 불순물 group은 charge-to-mass ratio가 26, 28, 40, 44이고 감소하는 불순물 group은 18, 20, 32 이다. 펄스의 duty ratio를 1/9(on/off) 초에서 5/5(on/off) 초로 증가시킴에 따라 제거율이 증가하는 불순물과 감소하는 불순물이 또한 나타났는데 수소 유량 실험과 그 group에 차이가 없었다. 이러한 실험결과는 수소 유량의 증가나 펄스 길이의 증가에 따라 가스의 종류에 관계없이 모두 증가하거나 감소할 것이라는 예측과는 다른 결과로서 이것에 대한 명료한 해석이 필요하다. 왜냐하면 위와 같은 운전조건에서 효율적인 불순물 제거를 위해서는 불순물 제거 운전 방법이 불순물의 종류에 따라 모두 달라져야 하기 때문이다. 본 연구에서는 이러한 특성을 불순물의 dissociation 에너지 관점에서 해석을 시도하였다.

• Journal of the Korean Institute of Gas
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• v.19 no.6
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• pp.28-33
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• 2015

In this study, a dual fuel engine fueled with natural gas and diesel was tested to investigate the effects of heating value variation of CNG fuel. CNG substitution rate which is defined as the ratio of CNG and diesel supplied in a heating value basis was fixed at 80%. The higher heating value was varied from $10,400kcal/Nm^3$ to $9,400kcal/Nm^3$ by mixing nitrogen gas with pure CNG and diesel fuel was injected at a fixed injection timing. The engine test results showed that thermal efficiency and power output were decreased as the heating value of mixed CNG fuel was decreased. And the peak cylinder pressure was also decreased but the ignition delay time and the combustion duration and timing were almost same.