• 대한한의학회지
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• 제24권1호
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• pp.155-168
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• 2003

This study was carried out to investigate the effect of Keuibi-tang (KBT) on the injury of gastric mucous membrane by stress and ethanol in mice. The normal group was non-inflammation elicited mice. The two control groups were mice with gastro-inflammation elicited by stress and ethanol. The two sample groups were mice administered KBT before gastro-inflammation elicitation. In the common morphology and histochemical change, the two control groups were observed with various injuries such as hemorrhagic erosion and ulcer, while the sample group was the same as the normal group. In the immunohistochemical change, the distributions of PNA and COX-1 treated with KBT noticeably increased over the control group (P<0.05). The distributions of $NF-{\kappa}B$ p50, COX-2 and TUNEL in the group treated with KBT were noticeably lower than in the control group (P<0.05). The distribution of KBT was the same as the normal group. According to the above results, it is supposed that KBT is applicable to gastritis and gastric ulcer due to stress and alcoholic drinks.

• 대한한방내과학회지
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• 제26권2호
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• pp.341-352
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• 2005

Objectives: This study was carried out to investigate the effects of Jecksodoodangkuisan(JD) and Jecksodoodangkuisankahyunjicho(JH) against Colonic Mucosal Ulcer induced by indomethacin in mouse. Methods: The normal group consisted of mice that were not inflammation-induced. The control group was untreated gastro-inflammation-elicited mice. The sample group mice were those administered BO, JD and JH after gastro-inflammation elicitation. Results: In the immunohistochemical change, the distribution of COX-1 in mice treated with BO, JD and JH noticeably increased than control group(P<0.05). The distributions of $NF-{\kappa}B$, p50, COX-2, ICAM-1, HSP70 and Substance P in mice treated with BO, JD and JH noticeably decreased more than control group(P<0.05). And JH was most effective treatment against Colonic Mucosal Ulcer in the immunohistochemical change. Conclusions: According to the above results, Jecksodoodangkuisan and Jeckmdoodangkuisankahyunjicho are applicable treatments for Colonic Mucosal Ulcer.

• Macromolecular Research
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• 제13권5호
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• pp.391-396
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• 2005

The polymerization of methyl methacrylate (MMA) was carried out using CuBr/bidentate phosphorus ligand catalyst systems. MMA polymerization with CuBr/phosphine-phosphinidene (PP) exhibited high conversion ($\~80\%$) in 5 h at $90^{\circ}C$ along with a linear increase of ln($[M]_0/[M]$) versus time, indicating constant concentration of the propagating radicals during the polymerization. The molecular weight of the prepared PMMA tended to increase with conversion, suggesting the living polymerization characteristic of the system. On the other hand, a large difference between the measured and theoretical molecular weight and a broad molecular weight distribution were observed, implicating possible incomplete control over the polymerization. This may have been caused by the low deactivation rate constant ($\kappa_{deact}$) of the system. The low $\kappa_{deact}$, would result in irreversible generation of radicals instead of reversible activation/deactivation process of ATRP. Polymerizations performed at different ligand to CuBr ratios and different monomer to initiator ratios did not afford better control over the polymerization, suggesting that the controllability of CuBr/phosphorus ligand system for ATRP is inherently limited.

• 한국해양공학회지
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• 제14권4호
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• pp.9-16
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• 2000

This paper deals with the numerical and experimental study on the characteristics of the flow around a sunken vessel. Numerical simulation of the two dimensional steady flow on the midship section are carried out by the CFD code which is developed by using finite volume method and which includes the standard $textsc{k}$-$\varepsilon$ model with standard wall function. A experimental study is also carried out for the 1/100 scale model in circulating water channel. A velocity fields around the ship are measuremed by using particle image velocimetry technique. And the fluid forces acting on the ship hull by uniform current are measured by two axis load cell. The computed and measured velocity fields on the midship section are compared with each other in the view point of velocity dstribution and reattachement length, which shows good agreement in quality. The drag force on the vessel also showed the same tendency in both computational and experimental results. However, the quantitative disagreements are shown due to the three dimensional effect of the experiment. The result are used to determine the functional efficiency and stability of the vessel as a artificial reef.

• 대한한방내과학회지
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• 제29권4호
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• pp.939-949
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• 2008

Objective : This study was carried out to investigate the effects of Jisildochehwan extract on indomethacin-induced gastric mucosal lesions of mice. as compared with misoprostol. Methods : Experimental mice were classified into four groups. No gastro-inflammation elicited mice were the normal group(NOR). Gastro-inflammation elicited mice were the control group (CON). Misoprostol-administered mice after gastro-inflammation elicitation were the misoprostol-administered group (MA). Jisildochehwan-administered mice after gastro-inflammation elicitation were the Jisildochehwan-administered group(JA). In this study, we examined superoxide dismutase(SOD) ability, anti-inflammatory ability arrangement of mucous-secreted cells. distribution of mucosal neck cells, mucosal surface cells. neutral mucous-secreted cells. PAS reaction. COX-1, $TNF-{\alpha}$, $NF-{\kappa}B$ p65 and iNOS. Results : The SOD ability of the Jisildochehwan group increased dose-dependently. The hemorrhagic erosion and the damage of arrangement of mucous-secreted cells increased in the CON group. but decreased in the MA and JA groups. The COX-1 positive were decreased in the CON group, but increased in the MA and JA groups. The distribution of mucosal neck cells and mucosal surface cells. PAS positive reaction of surface mucous cells were decreased in CON group, but increased in MA and JA group. $TNF-{\alpha}$, $NF-{\kappa}B$ p65 and iNOS increased in the CON group, but decreased in the MA and JA groups. In all the results, the effects were better in the JA group than in the MA group. Conclusion : Jisildochehwan extract was more effective than Misoprostol. Jisildochehwan has excellent protective effects on indomethacin-induced gastric mucosal lesions.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2009년 추계학술대회논문집
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• pp.13-18
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• 2009

Flight vehicles such as wheel wells and bomb bays have many cavities. The flow around a cavity is characterized as an unsteady flow because of the formation and dissipation of vortices brought about by the interaction between the free stream shear layer and the internal flow of the cavity. The resonance phenomena can damage the structures around the cavity and negatively affect the aerodynamic performance and stability of the vehicle. In this study, a numerical analysis was performed for the cavity flows using the unsteady compressible three-dimensional Reynolds-Averaged Navier-Stokes (RANS) equation with Wilcox's turbulence model. The Message Passing Interface (MPI) parallelized code was used for the calculations by PC-cluster. The cavity has aspect ratios (L/D) of 2.5 ~ 7.5 with width ratios (W/D) of 2 ~ 4. The Mach and Reynolds numbers are 0.4 ~ 0.6 and $1.6{\times}106$, respectively. The occurrence of oscillation is observed in the "shear layer and transient mode" with a feedback mechanism. Based on the Sound Pressure Level (SPL) analysis of the pressure variation at the cavity trailing edge, the dominant frequencies are analyzed and compared with the results of Rossiter's formula. The dominant frequencies are very similar to the result of Rossiter's formula and other experimental data in the low aspect ratio cavity (L/D = ~ 4.5). In the large aspect ratio cavity, however, there are other low dominant frequencies due to the leading edge shear layer with the dominant frequencies of the feedback mechanism. The characteristics of the acoustic wave propagation are analyzed using the Correlation of Pressure Distribution (CPD).

• 설비공학논문집
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• 제28권1호
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• pp.1-6
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• 2016

This paper studies the wind pressure distribution over the Commonwealth Advisory Aeronautical Council building model (CAARC model) using CFD. We also considered the interaction between the CAARC model and other buildings. The Reynolds number based on the building height was 380,000. The number of sells for the simulation was about 500,000. The wind pressure was lowest when the wind direction was blowing at an angle 45 degrees of the CAARC model. When the gap between the two buildings in front of the CAARC was over 1/2 the horizontal length of the CAARC model, the wind pressure was higher than the pressure without the two buildings. When the distance between the two front buildings and the CAARC was less than 1.5 times the vertical length of the CAARC model, the wind pressure increased. Accordingly, the relative distance between two buildings or the distance from the CAARC model should be considered when extra wind exists due to other buildings.

• 물과 미래
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• 제29권2호
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• pp.129-141
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• 1996

일점연속 채취, 멱 속도 분포 및 Laursen의 토사농도 분포식을 이용한 총 부유 유사량 계산방법을 제안하였다. 이 방법은 미국 리오그안데 강에서 채취한 자료에 의해 검증되었다. 이 방법으로 계산된 농도분포는 $\beta$, $\kappa$, 그리고 w의 보편적인 값을 사용하여 계산한 보정 전수심 채취방법과 잘 일치하였다. 지역특성에 맞는 농도와 속도 분포식의 계수 x 와 z를 사용하였을 때는 더 좋은 결과를 얻을 수 있었다. 일점 채취에 사용한 이 방법과 일반적으로 많이 쓰는 전수심 채취를 사용한 방법과의 총 유사량의 차이는 채취때 생길 수 있는 오류 정도로 작은 것이었다. 일점 연속 채취에 의한 총 부유 유사량 측정은 여러 가지 중요한 이점을 가지고 있다. 채취 시간에 및 비용을 절감할 수 있으며 채취를 자주 할 수 있고 유사량 변화에 신속하게 대응할 수 명실상부 또한 이 방법은 미래에 추구해야 할 자동채취 방법으로 사용될 수 있다.

• 한국환경보건학회지
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• 제38권4호
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• pp.351-359
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• 2012

Objectives: This study was conducted in order to investigate the specific correlation between physicochemical properties and bioactivity in ecdysteroids found in living organisms. Methods: The examined steroidal compounds were classified into three groups according to their relevance to ecdysone activity. Each compound molecule was completely drawn to automatically calculate its physicochemical parameters and docked against 20-hydroxyecdysone to calculate the total distance. Electronic charge distribution was also observed for each molecule. All procedures were conducted using a computational chemistry program. Results: Ecdysone agonists showed different ranges of parameter values, such as log P, hydrophilic-lipophilic balance (HLB), solubility parameter (SP), hydrophilic surface (HPS), hydrogen bond (HB) and Kappa 2, when compared with antagonists and steroids without ecdysone activity. They also showed a similar electronic charge distribution that is significantly different from the electron charge distribution of antagonists and steroids without ecdysone activity. The total distance values of agonists, estimated by docking them with 20-hydroxyecdysone, were relatively small but showed no correlation with binding affinity with receptor ligand. Conclusions: These results suggest that physicochemical properties such as steric and electronic effects, hydrophobicity and hydrogen bonding may operate in combination to determine the binding activity of ecdysteroids to the receptor protein.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2002년도 제24회 KOSCO SYMPOSIUM 논문집
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• pp.3-10
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• 2002

In this work, numerical parametric studies on spray combustion have been conducted. In simulation of turbulence, RNG ${\kappa}-{\varepsilon}model$ is adopted. Initial spray distribution is specified by Rosin-Rammler distribution function. Eddy break-up model is adopted as a combustion model. The parameters considered are inlet air temperature, swirl number, and SMD. With higher inlet air temperature, the axial velocities are increased and penetration of primary jet is stronger than that of lower inlet air temperature and temperature at the exit of combustor is more uniform. Combustion efficiency is improved with high inlet air temperature. The effect of swirl number on flow field is not significant. It affect only recirculation zone. So temperature at upstream of combustor is influenced. Combustion efficiency deteriorate as SMD of fuel spray increase.