• Journal of Advanced Marine Engineering and Technology
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• 제29권6호
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• pp.645-653
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• 2005

The effects of a WI(Water Injection) at the intake Pipe and an urea injection at the exhaust pipe for a 4-cylinder DI(Direct Injection) diesel engine were investigated experimentally The water quantity was controlled by temperature of intake manifold and MAF(Manifold Air Flow). In addition, the urea quantify was controlled by NOx quantify and MAF. Effects of WI system, urea-SCR system and tandem system were investigated for with and without EGR(Exhaust Gas Recirculation). As the results. the SUF(Stoichiometric Urea Flow) and NOx map were obtained. In addition, NOx results can be visualized with engine speed and engine load. It was concluded. therefore, that the NOx reduction effects of the tandem system without the EGR were more than those with the EGR base engine.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회B
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• pp.3294-3299
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• 2007

These days the exhaustion of petroleum resources and environmental problems are getting serious. Many researchers are focused on low emission and high performance vehicles. Therefore, we should concern about emission regulation when we design a new car. In this study, we investigated the characteristics of the traditional mechanical engine cooling systems which control the engine temperature using engine speed and wax type thermostat. This experiment used three components which are Radiator fan, water pump and water valve controlled by an electronic system based on the engine status (load, speed). We elucidated how different between traditional mechanical cooling system and electronic cooling system which control coolant temperature and coolant flow rate in a DI diesel engine in this paper. The results revealed a fuel saving and an emission (CO, HC) reduction on NEDC cycle.

• Advances in materials Research
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• 제3권3호
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• pp.175-183
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• 2014

Natural rubber bound phenolic antioxidant, 2,6-di-tert-butyl-4-vinylphenol (2,6-DBVP), was prepared from natural rubber and 2,6-DBVP in both solution and melt state. The 2,6-DBVP had been synthesized from 3,5-di-tert-butyl-4-hydroxybenzaldehyde and methyltriphenylphosphonium iodide ($MePPh_3I$) by Wittig reaction ($0^{\circ}C$ for 2 hrs, $N_2$ atmosphere). The conditions for preparation of natural rubber bound 2,6-DBVP (NR-DBVP) were optimized for both solution state (1 phr BPO and 8 phr 2,6-DBVP at $70^{\circ}C$ for 2 hrs) and for melt state (1 phr BPO and 8 phr 2,6-DBVP at $70^{\circ}C$ for 10 mins, with rotor speed of 60 rpm). A thermoplastic vulcanizate was obtained using a compatibilizer, polypropylene modified with phenolic resin (PhHRJ-PP), in a closed mixer ($180^{\circ}C$ for 3 mins, rotor speed 60 rpm). The antioxidant properties of vulcanized NR-DBVP, using phenolic as the vulcanization system, were similar to NR with the conventional antioxidant BHT. In addition, the antioxidant, water leaching property of the thermoplastic vulcanizate of NR-DBVP/PP were good in comparison to a NR blend with BHT; the morphologies of these thermoplastic vulcanizates were similar.

• International Journal of Fluid Machinery and Systems
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• 제5권2호
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• pp.49-59
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• 2012

The present study is devoted to the influence of a superposed radial inflow in a rotor-stator cavity with a peripheral opening. The flow regime is turbulent, the two boundary layers being separated by a core region. An original theoretical solution is obtained for the core region, explaining the reason why a weak radial inflow has no major influence near the periphery of the cavity but strongly affects the flow behavior near the axis. The validity of the theory is tested with the help of a new set of experimental data including the radial and tangential mean velocity components, as well as three components of the Reynolds stress tensor measured by hot-wire anemometry. The theoretical results are also in good agreement with numerical results obtained with the Fluent code and experimental data from the literature.

• Journal of Magnetics
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• 제14권2호
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• pp.80-85
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• 2009

The mineral dissolution sensor system using GMR-SV and glass/Mg(200 nm) was prepared and characterized. The magnetic field sensitivity of GMR-SV to microscopic magnetic variation was about 0.8%/Oe. The change that occurs when Mg-film dissolves in water, the solubility of water, which is one of the basic properties of mineral water, was sensed by measuring the subtle variation of an electric current. In the case of edible water with Mg mineral added, bubbles were generated on the surface of the Mg film in the first 45 minutes, and the number of drops that were dissolved more rapidly than with the tap and DI waters later reduced to zero. For the edible water samples that each had different mineral Mg concentrations, the Mg solubility speed significantly differed. After injecting Mg film into the edible water, the magnetoresistance of the output GMR-SV signal decreased from a maximum of $45.4\;{\Omega}$ to a minimum of $43.6\;{\Omega}$. The measurement time was within 1 min, giving the rate of change ${\Delta}R/{\Delta}t=0.18\;{\Omega}/s$. This measurement system can be applied to develop a mineral Mg solubility GMR-SV sensor that can be used to sense the change from edible water to reduced alkali.

• 한국자동차공학회논문집
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• 제6권1호
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• pp.196-204
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• 1998

For the experimental measurement of instantaneous surface temperature of the piston of the DI mono cylinder diesel engine, the instantaneous temperature proves, data acquisition system, and grass-hopper type linkage system were developed. The instantaneous temperatures on the piston bowl, crown, lands and skirt were measured and analyzed, and the following conclusions were derived ; (i) The crank angle for the maximum instantaneous temperature during one cycle varies and moves back and forth by the measuring positions and engine speeds. (ii) The engine speeds, the positions of the measuring points and the cooling water temperature had an effect on the instantaneous temperature amplitude. (iii) The instantaneous temperature suing phenomena appeared on the temperature profiles of the piston crown, top and second land of ring, but on the temperature profiles of the parts of the third land of the fing and skirt, they didn't appear, (iv) The isothermal lines in the piston were acquired through the operation of the finite elements method using the measured temperatures as the boundary conditions.

• 한국식생활문화학회지
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• 제17권4호
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• pp.377-386
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• 2002

The purpose of this study was to investigate the effects of dietary Indongcho(L. japonica Thunb) powder on blood glucose, serum lipid levels and antioxidative enzymes in normal and streptozotocin(STZ)-induced diabetic rats. Four groups of rats(3-week-old inbred Sprague-Dawley male rats) were normal rats fed control diet(NC), diabetic rats fed control diet(DC), normal rats fed Indongcho powder diet(NI), and diabetic rats fed Indongcho powder diet(DI). Diabetes was induced by single injection of streptozotocin(60mg/kg B.W., i.p.). The animals were fed ad libium each of the experimental diet for 5 weeks. Food and water intakes were determined everyday. Blood glucose and serum total cholesterol levels were determined every week. After 5 weeks the animals were sacrificed and activities of antioxidant enzymes and lipid peroxidation products were determined in their liver and kidney homogenates. We also determined serum concentrations of total lipid(TL), total cholesterol(TC), triglycerides(TG) and HDL-cholesterol(HDL-C). Blood sugar and water intake were higher in diabetic group(DC and DI group) than normal group(NC and NI group) and were not significantly decreased by dietary Indongcho intake. Body weight gain and FER(feed efficiency ratio) were reduced by STZ treatment. But, Final body weight was recovered by Indongcho-contained diet. LHR(LDL-cholesterol/HDL-cholesterol) of the DI g re up was significantly lower than the other experimental groups(NC, NI and DC groups). The hepatic glucose 6-phosphatase(G6Pase) activity of the groups fed Indongcho diet(NI and DI group) was lower than the groups fed control diet(NC and DC group) and the G6Pase activity of NI group was recovered to the normal levels(p<0.05). However, The glutathione peroxidase(GPx) and glutathione reductase(GR) activities in liver and G6Pase activity in kidney were not statistically different between the control and diabetic control groups. Renal GST activity of the DI group was recovered by Indongcho intake. In conclusion, these results confirm oxidative stress in the liver and kidney of rats with STZ diabetes and antioxidative effect of Indongcho.

• 한국재료학회지
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• 제24권8호
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• pp.429-433
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• 2014

As the fabrication technology used in FPDs(flat-panel displays) advances, the size of these panels is increasing and the pattern size is decreasing to the um range. Accordingly, a cleaning process during the FPD fabrication process is becoming more important to prevent yield reductions. The purpose of this study is to develop a FPD cleaning system and a cleaning process using a two-phase flow. The FPD cleaning system consists of two parts, one being a cleaning part which includes a two-phase flow nozzle, and the other being a drying part which includes an air-knife and a halogen lamp. To evaluate the particle removal efficiency by means of two-phase flow cleaning, silica particles $1.5{\mu}m$ in size were contaminated onto a six-inch silicon wafer and a four-inch glass wafer. We conducted cleaning processes under various conditions, i.e., DI water and nitrogen gas at different pressures, using a two-phase-flow nozzle with a gap distance between the nozzle and the substrate. The drying efficiency was also tested using the air-knife with a change in the gap distance between the air-knife and the substrate to remove the DI water which remained on the substrate after the two-phase-flow cleaning process. We obtained high efficiency in terms of particle removal as well as good drying efficiency through the optimized conditions of the two-phase-flow cleaning and air-knife processes.

• 한국전기전자재료학회논문지
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• 제13권10호
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• pp.812-816
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• 2000

It is very important to understand the correlation of between inter dielectric(ILD) CMP process and various facility factors supplied to equipment to equipment system. In this paper, the correlation between the various facility factors supplied to CMP equipment system and ILD-CMP process was studied. To prevent the partial over-polishing(edge hot-spot) generated in the wafer edge area during polishing, we analyze various facilities supplied at supply system. With facility shortage of D.I water(DIW) pressure, we introduced an adding purified $N_2$(P$N_2$)gas in polishing head cleaning station for increasing a cleaning effect. DIW pressure and P$N_2$gas factors were not related with removal rate, but edge hot-spot of patterned wafer had a serious relation. We estimated two factors (DIW pressure and P$N_2$gas) for the improvement of CMP process. Especially, we obtained a uniform planarity in patterned wafer and prohibited more than 90% wafer edge over-polishing. In this study, we acknowledged that facility factors supplied to equipment system played an important role in ILD-CMP process.

• 생물환경조절학회지
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• 제6권4호
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• pp.250-257
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• 1997

본 연구의 목적은 온실재배 토마토에서 경직경의 경시적 변화와 식물체내 수분, 토양수분, 증산 및 일사량 등과의 관계를 정량적으로 파악하여 토마토 경직경의 monitoring에 의한 관개시기 진단 방법을 모색하는 것이다. 스트레인게이지로 제작한 경직경 미소변화 측정장치와 load cell을 이용하여 각각 경직경 변화 및 지상부 생체중의 변화를 1996년 7월 1일부터 16일까지 10분 간격으로 계측하였으며, 또한 토양 수분함량, 증산, 일사량 등도 동시에 관측하였다. 실험을 시작하기 전에 충분한 관개를 하였으며 이후는 외관상으로 위조증상이 나타나기 시작할 매 관개를 하였다. 생체중과 경직경은 매우 유사한 일변화를 보였는데 해뜰 무렵인 오전 6시경에 최대치에 이르고 이후 일사량과 증산의 증대에 따라서 감소하기 시작하여 중산이 최대에 이르는 시각보다 다소 늦은 오후 3시경에 최저에 달하였다가 일사 및 증산의 감소에 따라서 다시 증대하여 경직경의 변화와 체내수분함량의 변화와는 매우 밀접한 관계가 있었다. 수분부족 증상이 없었던 날들의 일당 경직경 증가량(DI) 및 생체중 증가량(DG)은 일사량과 높은정의 상관을 보였으나 수분부족장애를 받은 날들은 일사량에 따른 이들의 기대치보다 현저하게 낮아 생체중 및 경직경 증대가 매우 둔화되거나 오히려 감소하여 이를 기준으로 관개시기를 정확하게 판단하는 것이 가능하였다. 실험기간 중 7월 10일의 경우 외관상으로는 위조증상이 없었으나 증산량은 현저히 감소하여 식물체가 수분부족 상태였던 것으로 판단되었는데 이 날 토중 l0cm 및 20cm에서의 토양수분 포텐샬은 -0.2bar 이상으로 전일과 큰 차이가 없었으나 경직경 및 생체중의 증가는 현저히 둔화되어 수분 부족을 잘 반영하였다. 한편 낮 동안의 생체 중 최대감소량(ML)과 경직경 최대수축량(MC) 역시 일사량과 유의한 정의 상관을 보여 일사량 및 증산량 증대에 따라 체내 수분 손실량이 증대하고 이에 따라서 경직경이 감소하는 한계를 보였다. 그리고 식물의 수분장애가 심한 경우에는 일사량에 따른 이들의 기대치보다 현저하게 높았으나 수분장애가 미약한 경우에는 기대치와 구별하기가 어려워 이들을 기준으로 관개 시기를 정확하게 판단하기는 어려운 것으로 판단되었다. 따라서 관개시기의 판단에는 토양수분, MC 및 ML을 기준으로 하는 것보다 DG 또는 DI를 기준으로 하는 것이 효율적인 것으로 판단되었다.