• 한국연소학회:학술대회논문집
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• 한국연소학회 2014년도 제49회 KOSCO SYMPOSIUM 초록집
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• pp.101-102
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• 2014

Rising oil price and environmental problems are causing automotive industry to increase fuel efficiency. Improved fuel efficiency in gasoline engine was made possible by development of DISI gasoline engine. Since fuel is injected inside cylinder directly, in-cylinder temperature can be reduced than multi-port injection engine and this leads to increased compression ratio. However, engine performance is largely dependent on mixture formation process due to in-cylinder fuel injection. Especially for spray guided and air guided DISI gasoline engine, injection direction is important factor to mixture preparation. It is because interaction between intake flow and spray affect fuel-air mixture. Hence, in this study, mixture formation characteristics were analyzed by varying injection direction using KIVA 3V release2 code. Residual gas was considered for assuming combustion. Therefore, initial condition for in-cylinder temperature was set equal to the end state of exhaust stroke of combustion cycle. Since angle between intake air flow direction and spray direction affects fluid flow and evaporation field, mixture distribution was affected by fuel injection direction dominantly.

• 대한기계학회논문집B
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• 제27권1호
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• pp.69-75
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• 2003

In this study, his technique was applied to a GDI spray in order to investigate the mixture distribution. In addition, the homogeneity degree and diffusion effect according to ambient temperature in the high pressure chamber were analyzed by using an entropy analysis method. From this experiment, we could find that entropy analysis is very effective method for the analysis of mixture formation, and the entropy values increase with the progress of uniformity in diffusion Process. we tried to provide the fundamental data for parameter which effects on the spray macroscopic characteristics with mixture ratio of diesel and gasoline. In addition, the mixture formation was analyzed by using entropy analysis. The entropy analysis is based on the concept of statistical entropy, and it identifies the degree of homogeneity in the fuel concentration. From the entropy analysis results we could find that the direct diffusion phenomena is a dominant factor in the formation of a homogeneous mixture at downstream of GDI spray especially in vaporizing conditions. As to increasing ambient temperature and increasing gasoline rate, the entropy intensity using the statistic thermodynamics method is increased because evaporation rate is higher gasoline than diesel.

• 한국지반공학회논문집
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• 제29권2호
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• pp.57-64
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• 2013

본 논문에서는 정수슬러지의 고함수비 문제를 해결하고 재활용을 촉진하기 위해 정수슬러지와 화강풍화토를 다양한 배합비로 혼합하여 슬러지혼합토(sludge mixture)를 제작하고, 다양한 실내 시험을 통해 슬러지혼합토의 물리적 특성과 불포화 특성을 분석하였다. 시험 결과, 정수슬러지 함량이 증가함에 따라 동일한 모관흡수력에 대응하는 체적 함수비는 증가하였다. 또한 정수슬러지 함량 또는 세립분 함량이 증가함에 따라 공기함입치는 0.9kPa에서 2.4kPa로 증가하였다. 슬러지혼합토의 포화투수계수 값과 함수특성곡선의 결과를 활용하여 강우 시 침투해석을 수행하는데 있어서 중요한 인자인 불포화 투수함수를 산정하였다.

• 한국식품영양학회지
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• 제36권6호
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• pp.535-542
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• 2023

We investigated the anti-inflammatory effects of shiitake mushroom and kelp (SMK) mixture extracts in lipopolysaccharide (LPS)-stimulated murine RAW 264.7 cells. Treatment of RAW 264.7 cells with LPS significantly increased NO (nitric oxide) production, pro-inflammatory cytokines (tumor necrosis factor (TNF)-α, interferon (IFN)-γ, interleukin (IL)-6, and IL-1β), and inflammation-related genes (COX-2 and inducible nitric oxide synthase (iNOS)). In cytotoxicity testing using RAW 264.7 cells, SMK mixture extracts in the range of 1-16 ㎍/mL did not inhibit cell proliferation. However, SMK mixture extracts significantly inhibited NO production in a dose-dependent manner (p<0.05). SMK treatment significantly decreased TNF-α, IL-6, IFN-γ, and IL-1β levels compared to the LPS group, and similarly, pro-inflammatory cytokine mRNA levels also decreased. SMK mixture extracts reduced the mRNA expression of COX-2 and iNOS in RAW 264.7 cells compared to LPS (p<0.05). The above results show that SMK mixture extracts suppressed the inflammatory response induced by LPS. In particular, the extracts were shown to regulate the inflammatory response by suppressing the expression of inflammatory cytokines and inflammation-related enzymes.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2011년도 춘계학술대회 논문집
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• pp.845-846
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• 2011

• 멤브레인
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• 제14권4호
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• pp.304-311
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• 2004

PTMSP-PEI 복합막과 PTMSP-Silica-PEI 복합막을 제조하고, 막의 특성을 FT-IR, GPC, SEM 등을 사용하여 조사하였다. PTMSP-Silica-PEI 복합막은 silica의 함량이 23∼60 wt%로 증가하면서 입자의 크기는 점차 작아지고 입자의 분포는 균일하게 되었다. PTMSP-PEI 복합막과 PTMSP-Silica-PEI 복합막에 의한 $H_2$/$N_2$ 혼합기체분리는 $25^{\circ}C$, $\Delta$P 5 psi∼30 psi 범위에서 조사되었다. PTMSP-PEI 복합막과 PTMSP-Silica-PEI 복합막들의 수소에 대한 분리인자($\alpha$, $\beta$, (equation omitted)) 값은 투과셀의 압력이 증가할수록 그리고 silica의 함량이 증가할수록 증가하였다. $25^{\circ}C$, $\Delta$P 30 psi에서 PTMSP-PEI 복합막의 수소에 대한 $\alpha$, $\beta$, (equation omitted) 값은 2.28, 1.58, 1.44이고 silica 60 wt%인 PTMSP-Silica-PEI 복합막의 수소에 대한 $\alpha$, $\beta$, (equation omitted) 값은 3.34, 1.95, 1.72 이었다.

• Journal of the Korean Data and Information Science Society
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• 제18권3호
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• pp.745-755
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• 2007

The concept of slope rotatability introduced by Hader and Park(1978) is available when we are interested in the difference of the responses. Since there can be constraints on the factor levels in mixture experiments, there arises a need for adaptation of the concept of slope rotatability and the measure to assess it. In this article, measures of slope rotatability in mixture experiments are proposed to quantify the amount of slope rotatability for a given design. Measures for a restricted region design as well as for an unrestricted region design are presented. Then, the designs having different optimalities are compared with respect to these measures by some examples.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2008년 영문 학술대회
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• pp.519-524
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• 2008

A numerical study is conducted to investigate propulsion performance enhancement based on S225 experiment case of ISL(French-German Research Institute of Saint-Louis)'s superdetonative ram accelerator. For govern equation, multi-species Navier-Stokes equation coupled with Baldwin-Lomax turbulence modeling is used. Govern equation is discretized by Roe's FDS and integrated by LU-SGS time integration. Detailed chemical reaction about $H_2/O_2/CO_2$ for high pressure is considered. $2H_2+O_2+2.5CO_2$ mixture was used for propellant gas. For the same over-driven factor, the launching speed of computation was faster than one of S225. Another configuration and condition of S225 was applied. A flame structure is very different from S225. For strong mixture case, it shows ignition by viscous effect. Acceleration and speed increment is higher than S225 computation and experiment. By using more strong mixture, propulsion performance was enhanced.

• 멤브레인
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• 제6권4호
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• pp.250-257
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• 1996

글루탈알데히드와 황산을 이용하여 가교된 키토산 복합막을 제조하였다. 제조된 복합막은 글루탈알데히드와 황산용액을 이용하여 표면말을 선택적으로 가교하엿다. 제조된 키토산 막에서의 키토산과 아세트산간의 착체형성의 영향을 관찰하기 위하여 수산화나트륨으로 중화하여 성능을 비교하였다. 황산으로 표면을 가교한 경우 코팅된 활성층의 투과증발에 대한 영향을 관찰하였다. 글루탈알데히드로 가교된 키토산복합막은 지지체의 종류를 변화시키면서 투과증발성능을 비교하였다. 지지체의 순수투과성능이 증가할수록 투과유량은 비슷한 값들을 유지하였으며, 선택도는 증가하다가 다시 감소하는 경향을 나타내었다. 수산화나트륨으로 키토산을 중화시킨 경우에는 선택도는 감소하였고 투과유량은 유지되는 경향을 나타내었다. 황산을 이용하여 표면을 이온가교시킨 경우 키토산 복합막은 활성충우ㅏ 두께가 증가할수록 가교시간이 증가하여야 최적의 가교조건을 나타내었다.

• 한국방재학회 논문집
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• 제11권2호
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• pp.75-80
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• 2011

본 연구의 주목적은 에너지 비율 인자와 위상각을 이용한 연성포장의 피로예측 모델을 개발하는 것이다. 본 연구에서 도입된 에너지 비율 인자와 위상각은 점탄성 재료의 기본적인 성질을 반영하기 위하여 사용되었다. 에너지 비율 인자는 가상 방출 에너지와 시험 중 파괴시 까지의 누적 방출 에너지의 비로 정의된다. 위상각은 아스팔트 혼합물의 응력과 변형률의 차이로부터 발생한다. 아스팔트 콘크리트 혼합물의 실험결과를 이용하여 위상각이 측정 되었으며 초기 stiffness와 초기 위상각의 관계가 제시 되었다. 본 연구 결과 아스팔트 콘크리트 혼합물의 점탄성 재료라는 고유한 성질을 반영할 수 있는 에너지 비율 인자와 위상각을 활용한 연성포장용 피로 예측 모델이 제안되었다.