• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 춘계학술대회 논문집
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• pp.1609-1612
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• 2005

The effects of injection molding conditions on the uniformity and brightness of light guide plate(LGP) with micro-patterns were investigated in the present study. An injection molding system for stampers with mirco-pattern was designed and manufactured to perform experiment. Variations of injection molding speed, mold and melt temperature for LGP were considered in this work. Also, injection molding characteristics of LGP were investigated by numerical analysis using plastic injection molding commercial code. It was shown that injection molding conditions such as injection speed, melt temperature and mold temperature can have an effect on the uniformity and brightness of light guide plate.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2006년도 제26회 춘계학술대회논문집
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• pp.130-134
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• 2006

분사면 냉각성능을 개선하기 위한 액체로켓 엔진 연료 매니폴드내의 분리판 설치에 따른 분사균일성 변화를 관찰하였다. 3차원 전산유동해석으로 5개 후보 설계에 대하여 분사균일성을 비교하였으며 최적설계에 대하여 측정결과와 비교함으로써 해석방법을 검증하였다. case I과 II는 매니폴드로 공급되는 유량 전체가 분리판 아래로만 흘러 유속이 크게 증가한다. 하지만 분리판이 끝나는 지점에서의 유속변화와 분사면 중심에서의 유량의 집중으로 분사균일성이 크게 저하된다. 이에 비해 분리판이 입구에서 떨어져 장착된 case III와 IV는 유동이 분리판 위, 아래로 흐를 수 있어 유량집중이 완화되므로 균일한 분사특성을 가진다. 비교한 5가지 설계 중 냉각성능과 분사균일성 측면에서 case IV가 최적으로 판단된다.

• Design & Manufacturing
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• 제8권2호
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• pp.41-45
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• 2014

Automated polishing apparatus based on the research have been developed. The research is improvement of polishing process for surface quality and uniformity improvement of preform injection mold core. Surface quality of preform core have influence on ejecting and product quality after injection molding. Thus, the current being made by hand to automate the polishing process, the surface of the preform to improve the quality and uniformity improvement. First made a division by analyzing manual process a step-by-step. And draw a mechanism for converting mechanical movement. Automated polishing apparatus for preform core was developed, through which shortens production time and were able to secure the safety of the worker.

• 한국기계가공학회지
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• 제9권6호
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• pp.21-28
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• 2010

This study shows an optimization procedure for an automatic determination on the gate position to ensure the fill-uniformity within a part cavity by using the injection molding simulation. For an optimization, the maximum pressure-difference within a part cavity induced at the stage of filling is used to evaluate degree of fill-uniformity. In addition, a direct search scheme based on the reduction of design space is developed and applied in the optimization problem. This corresponding proposed methodology was applied in the optimization on the gate location for a CD-tray molding, as a result, showed the improvement of the fill-uniformity within the cavity.

• 항공우주기술
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• 제1권2호
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• pp.113-122
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• 2002

3단형 과학로켓의 주엔진 추진제의 분사균일성에 대하여 수치해석을 수행하고 설계 개선안을 도출하였다. 분사기 유로는 동일한 압력강하를 가지는 다공성 매질로 처리하였다. 산화제와 연료 모두 공급 유로의 반대쪽에서 분사속도가 높은 것으로 예측되었으며 이는 유동정체에 따른 정압 상승에 기인한다. 산화제 매니폴드 내부의 수직분리판에 유로를 구성함으로써 매니폴드 중심과 외곽에서의 분사균일성을 향상시킬 수 있었다. 산화제 공급유로가 경사를 가지더라도 분사균일성과 압력손실에 미치는 영향은 거의 없었다. 또한 산화제/ 연료에 대한 분사속도로부터 혼합비의 분포를 예측하였다.

• International Journal of Precision Engineering and Manufacturing
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• 제7권1호
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• pp.51-56
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• 2006

A computer code was developed to simulate both the thermal stresses introduced during the post-filling stage and the in-plane deformation after ejection process by finite element method based on the plane stress theory. The computer simulation was applied to the mold design of a 2 inch light guide plate (LGP) for thin film transistor (TFT)-liquid crystal displays (LCD). With injection molding experiments based on the design of experiments (DOE) technique, the influences of the processing conditions in injection molding on brightness and uniformity of the LGP were investigated, and the optimal processing parameters were selected to increase the brightness and uniformity. The verification experiment showed that the brightness and uniformity of the LGP were increased dramatically under the selected optimal processing conditions.

• 생물환경조절학회지
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• 제8권4호
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• pp.223-231
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• 1999

육묘장의 두상관수장치는 균일하게 관수되어야 모종도 균일하게 성장한다. 본 연구에서는 부채꼴 분사노즐을 이용한 두상관수장치의 노즐 설치위치에 따른 관수상태를 조사하여 균일관수방법을 구명하였다. 살수량은 주행속도에 반비례하였고, 관수균일도는 노즐과 관수면과의 거리에 큰 영향을 받으며 주행속도의 영향은 없었다. 단일노즐에 의한 두상관수인 경우 노즐 끝에서 관수면이 60cm 이상 멀어질수록 관수균일도가 향상되며, 연속노즐에 의한 두상관수인 경우 관수면이 노즐분사 각도의 2차 교차점에 위치할 때 관수균일도가 가장 좋은 것으로 나타났다. 두상관수장치의 균일관수를 위해서는 작물의 머리높이가 분사노즐의 2차교차점에 일치하도록 노즐의 위치를 정해야 하며 작물의 자람에 따른 노즐대 놀이를 조절해 주는 것이 바람직한 것으로 판단된다.

• 한국분무공학회지
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• 제25권4호
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• pp.154-161
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• 2020

A single spray plume is the basic unit of the entire spray plume and is an important factor in understanding the spray characteristics. However, since the multi-hole GDI injector has a narrow spray angle, the superposition of the spray plumes occurs severely. Therefore, the spray uniformity and the spray atomization characteristics of a single spray plume were analyzed in this study using a single-hole GDI injector. Five single-hole GDI injectors with different nozzle hole diameters were used in the experiment. The uniformity of the spray was evaluated through the analysis of the spray pattern images. In addition, the atomization characteristics were compared using the diameter distribution of the spray droplets obtained using PDPA. As a result, the larger diameter of the nozzle hole, the less uniformity of the spray, and the injection pressure did not have a significant effect on the spray uniformity. It is judged that the surface roughness of the injector has a greater effect on spray uniformity than the diameter of the nozzle hole. Also, the size of the spray droplets increased sharply when the diameter of the nozzle hole was 230 ㎛.

• 소성∙가공
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• 제11권4호
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• pp.341-348
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• 2002

For the light guide plate of the TFT-LCD, there have been increasing demands for higher brightness, thin and light-weight design, and lower power consumption. To meet these demands, a micro-prism-type frontlight that integrates a prismatic sheet and a light-guiding plate has been developed. In this paper, the influences of processing conditions on the brightness were studied lot the injection molding of the light guide plate. Based on the experiment with an actual mold, the design of experiments and the neural network theory were used lot choosing the optimal processing parameters to increase the brightness and the uniformity. The verification experiment also showed that the brightness and the uniformity were increased dramatically with the chosen processing conditions.

• 한국자동차공학회논문집
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• 제21권5호
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• pp.15-24
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• 2013

Numerical studies were conducted to investigate the internal flow field and combustion characteristics of DISI engine with methanol blended in gasoline. Dual injection was applied and the characteristics were compared to single injection strategy. The amount of the fuel injection was corresponded to air-fuel ratio of each fuel for complete combustion. The preforming model in this study, software STAR-CD was employed for both modeling and solving. The operating speed condition were at 4000 rpm/WOT (Wide open throttle) where the engine was fully warmed. The results of single injection with M28 showed that the uniformity, equivalence ratio, in-cylinder pressure and temperature increased comparing to gasoline (M0). When dual injection was applied, there was no significant change in uniformity and equivalence ratio but the in-cylinder pressure and temperature increased. When M28 fuel and single injection was applied, the CO (Carbon monoxide) and NO (Nitrogen oxides) emission inside the combustion chamber increased approximately 36%, 9% comparing with benchmarking case in cylinder prior to TWC (Three Way Catalytic converter). When dual stage injection was applied, both CO and NO emission amount increased.