• 한방안이비인후피부과학회지
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• 제18권1호
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• pp.61-70
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• 2005

Objective : This study was performed to investigate the effects of OWT on allergic bronchial asthma. Methods : The mice were divided into 4 groups induced the allergic bronchial asthma : Three groups(OWT-1, OWT-2, OWT-3) treated OWT and non-treated group(Control). Three oral administration of the herbal solution of OWT were carried out 1 lime a day for 2 weeks before antigen sensitization. 2 days later, the mice were sensitized with a subcutaneous injection of ovalbumin(OA) and then 13 days later they were provoked with OA aerosols. Then the cell numbers in bronchoalveolar lavage fluid(BALF), serum level of IgE, WBC, RBC and HCB were measured. Results : 1. On the neutrophil in BALF, OWT-1 group is significantly increased compared with the control group. 2. On the eosinophil in BALF, OWT-1 group tends to decrease compared with the control group but insignificant. 3. On the lymphocyte in BALF, OWT-2 group is significantly decreased compared with the control group. 4. On the macrophage in BALF, OWT-2 group is significantly increased compared with the control group. 5. On the serum IgE, groups OWT-1, OWT-2 and OWT-3 are significantly decreased compared with the control group. 6. On WBC in blood, OWT-1 group is significantly decreased compared with the control group. Conclusions : Based on the above results, it is assumed that the oral administration of OWT can help the treatment of allergic bronchial asthma.

• 한방안이비인후피부과학회지
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• 제18권1호
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• pp.94-103
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• 2005

Objective: This study was performed to investigate the effects of YTT on allergic bronchial asthma. Methods: The mice were divided into 4 groups induced the allergic bronchial asthma : Three groups(YTT-1, YTT-2, YTT-3) treated YTT and non-treated group(Control). Three oral administration of the herbal solution of YTT were carried out 1 time a day for 2 weeks before antigen sensitization. 2 days later, the mice were sensitized with a subcutaneous injection of ovalbumin(OA) and then 13 days later they were provoked with OA aerosols. Then the cell numbers in bronchoalveolar lavage fluid(BALF), serum level of IgE, WBC, RBC and HGB were measured. Results: 1. On the neutrophil in BALF, groups of YTT-2 and YTT-3 are significantly increased compared with the control group. 2. On the eosinophil in BALF, groups of YTT-1 and YTT-3 are significantly decreased compared with the control group. 3. On the lymphocyte in BALF, YTT-3 group is significantly increased compared with the control group. 4. On the macrophage in BALF, groups of YTT-1 and YTT-3 groups tend to increase. 5. On the serum IgE, groups YTT-1, YTT-2 and YTT-3 are significantly decreased compared with the control group. 6. On WBC in blood, groups of YTT-2, YTT-3 are significant1y decreased compared with the control group. Conclusions: Based on the above results, it is assumed that the oral administration of YTT can help the treatment of allergic bronchial asthma.

• KSBB Journal
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• 제11권4호
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• pp.405-410
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• 1996

내부 순환 장치를 대규모화함에 따른 혼합특성의 변화를 추적자의 분산실험을 통하여 고찰하였다. 분산특성을 나타내는 무차원수 Bodenstein 수를 5L, 5 50L, 500L 규모의 세 장치에서 공탑기체속도, 액체 순환속도, 포기관의 높이에 대한 직경비의 변화, 빛 반응관의 직경에 대한 포기관의 직경비의 영향에 따 나타내었다. 5L 규모의 장치에서 Bo 수는 공탑 기체속도의 증가에 따라 증가하다 가스 해리 현상의 발생으로 증가폭이 둔해지는 경향을 나타내었으며, 5 50L와 500L 장치에서는 공탑기체속도의 증가에 따라 Eo 수가 감소하였는데, 이는 역혼합의 영향이 크게 나타난 것으로 판단되었다. 또한, 500L 규모 장 치에서 Eo 수의 변화는 50L 장치에서 보다 낮은 공 탑기체속도하에서 변화하는 것으로 보아 대규모화에 따라 흔합이 더욱 빨리 발생함을 알 수 있었다. 차원 해석을 통하여 각 변수틀간의 상관관계를 구하였고, 회귀분석을 통하여 다음과 같은 결과식을 구하였다.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2010년 춘계학술대회논문집
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• pp.530-533
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• 2010

This paper presents numerical analysis and design optimization of various turbine blade cooling techniques with three-dimensional Reynolds-averaged Navier-Stokes(RANS) analysis. The fluid flow and heat transfer have been performed using ANSYS-CFX 11.0. A fan-shaped hole for film-cooling has been carried out to improve film-cooling effectiveness with the radial basis neural network method. The injection angle of hole, lateral expansion angle of hole and ratio of length-to-diameter of the hole are chosen as design variables and spatially averaged film-cooling effectiveness is considered as an objective function which is to be maximized. The impingement jet cooling has been performed to investigate heat transfer characteristic with geometry variables. Distance between jet nozzle exit and impingement plate, inclination of nozzle and aspect ratio of nozzle hole are considered as geometry variables. The area averaged Nusselt number is evaluated each geometry variables. A rotating rectangular channel with staggered array pin-fins has been investigated to increase heat transfer performance ad to decrease friction loss using KRG modeling. Two non-dimensional variables, the ratio of the eight diameter of the pin-fins and ratio of the spacing between the pin-fins to diameter of the pin-fins selected as design variables. A rotating rectangular channel with staggered dimples on opposite walls are formulated numerically to enhance heat transfer performance. The ratio of the dimple depth and dimple diameter are selected as geometry variables.

• 한국기계가공학회지
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• 제14권3호
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• pp.36-42
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• 2015

The aspherical lens was designed to be able to array a focal point. For this reason, it has very curved surface. The aspherical lens is fabricated by injection molding or diamond turning machine. With the aspherical lens, tool marks and surface roughness affect the optical characteristics, such as transmissivity. However, it is difficult to polish free form surface shapes uniformly with conventional methods. Therefore, in this paper, the ultra-precision polishing method with MR fluid was used to polish an aspherical lens with 4-axis position control systems. A Tool path and polishing mechanism were developed to polish the aspherical lens shape. An MR polishing experiment was performed using a generated tool path with a PMMA aspherical lens after the turning process. As a result, surface roughness was improved from $R_a=40.99nm$, $R_{max}=357.1nm$ to $R_a=4.54nm$, $R_{max}=35.72nm$. Finally, the MR polishing system can be applied to the finishing process of fabrication of the aspherical lens.

• 대한기계학회논문집B
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• 제36권7호
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• pp.767-774
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• 2012

신형경수로인 APR1400의 안전주입탱크에는 유량조절장치가 설치되어있다. 이러한 유량조절장치는 안전주입탱크 내부의 수위에 따라 유량조절장치 내부에 위치한 와류실의 유동양식이 변하도록 설계되어 있어, 피동적으로 유량이 조절되는 특성을 가지고 있다. 그러나 고유량에서 저유량으로 전환되는 과정에서 유동의 관성에 의해 상부 기체가 방출되는 현상이 존재하여, FD 성능에 영향을 줄 수 있다. 본 논문에서는 전산유체역학 코드인 CFX 코드를 활용하여 안전주입탱크의 유량전환현상시 기체의 방출현상에 대해 이상유체 자유수면모델 적용하여 계산하였다. 이를 통해 안전주입수의 수위 및 상부 충전기체의 거동을 평가하여 FD 성능특성에 미치는 영향을 분석하였다. 그 결과, 유량전환구간에서 자유수면의 높이가 순간적으로 낮아지게 되어, 상부의 기체가 일부 방출되는 것으로 평가되었으나, FD 성능특성에는 큰 영향을 미치지 않는 것으로 평가되었다.

• 대한임상독성학회지
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• 제8권1호
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• pp.30-36
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• 2010

Purpose: The purpose of this study is to analyze the clinical characteristics of anaphylaxis and anaphylactic shock caused by bee venom. Methods: We retrospectively collected the data of the patients who experienced anaphylaxis caused by natural bee sting or acupuncture using bee venom from January 1999 to December 2008. Seventy subjects were divided into the shock and non-shock groups. The clinical characteristics, sources of bee venom, treatments and outcomes were compared between the two groups. Results: The mean age of the subjects was $45.5{\pm}16.3$ years old and the number of males was 44 (62.9%). There were 25 patients in the shock group and 45 in the non-shock group. The age was older (p=0.001) and females (p=0.003) were more frequent in the shock group. Transportation to the hospital via ambulance was more frequent in the shock group (p<0.001). No difference was found in species of bee between the two groups. The cephalic area, including the face, was the most common area of bee venom in both groups. Anaphylaxis caused by bee sting commonly occurred between July and October. Cutaneous and respiratory symptoms were the most frequent symptoms related to anaphylaxis. Cardiovascular and neurologic symptoms were more frequent in the shock group. The amount of intravenously administered fluid and subcutaneous injection of epinephrine were much more in the shock group than that in the non-shock group. Conclusion: Older age was the factors related to anaphylactic shock caused by bee venom. Further validation is needed to evaluate the gender factor associated with shock.

• Biomolecules & Therapeutics
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• 제19권2호
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• pp.224-230
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• 2011

In order to develop silk peptide (SP) preparations possessing cognition-enhancing effect, several candidates were screened through in vitro assays, and their effectiveness was investigated in facilitated brain aging model rats. Incubation of brain acetyl-cholinesterase with SP-PN (1-1,000 ${\mu}g/ml$) led to inhibition of the enzyme activity up to 35%, in contrast to a negligible effect of SP-NN. The expression of choline acetyltransferase (ChAT) mRNA of neural stem cells expressing ChAT gene (F3.ChAT) was increased by 24-hour treatment with 10 and 100 ${\mu}g/ml$ SP-NN (1.35 and 2.20 folds) and SP-PN (2.40 and 1.34 folds). Four-week subcutaneous injections with D-galactose (150 mg/kg) increased activated hippocampal astrocytes to 1.7 folds (a marker of brain injury and aging), decreased acetylcholine concentration in cerebrospinal fluid by 45-50%, and thereby impaired learning and memory function in passive avoidance and water-maze performances. Oral treatment with SP preparations (50 or 300 mg/kg) for 5 weeks from 1 week prior to D-galactose injection exerted recovering activities on acetylcholine depletion and brain injury/aging as well as cognitive deficit induced by D-galactose. The results indicate that SP preparations restore cognitive functions of facilitated brain aging model rats by increasing the release of acetylcholine, in addition to neuroprotective activity.

• 대한기계학회논문집B
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• 제24권6호
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• pp.785-791
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• 2000

GDI (Gasoline Direct Injection) engines are considered as one of the candidates for next generation engines of passenger cars, which reduce exhaust emissions and fuel consumption. In GOI engines, a high-pressure gasoline supply system is required to directly inject the fuel to combustion chambers. Because of low lubricity of gasoline fuel, the clearance between a plunger and a barrel in GDI fuel pumps is too wide to achieve smooth hydrodynamic lubrication. Thus, it is difficult to generate high-pressure condition in GDI fuel pump since large amount of leakage flow occurs between the plunger and the barrel In this study, an optimum plunger design is presented to minimize leakage in the aspect of flow control. This paper analyzes leakage flow characteristics in the clearance to improve pumping performance of GDI fuel pumps. Effects of groove in the plunger are studied according to variations of depth and width. Evaluations of pumping performance are determined by the amount of pressure drop in the leakage path assuming a constant leakage flows. Both of turbulence and incompressible models are introduced in CFD (Computational Fluid Dynamics) analysis. Design parameters have been introduced to minimize leakage in limited space, and a methodological study on geometrical optimization has been conducted. As results of CFD analysis in various geometrical cases, optimum groove depths have been found to generate maximum sealing effects on gasoline fuel between the plunger and the barrel. This procedure offers a methodological way of an enhancement of plunger design for high-pressure GDI fuel pumps.

• Geomechanics and Engineering
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• 제14권1호
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• pp.9-17
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• 2018

Brazilian splitting tests, uniaxial compression tests and triaxial compression tests are carried out on the coal samples cored from Shanxi group $II_1$ coal seam of Jiaozuo coal mine, Henan province, China, to obtain their property parameters. Considering the bedding has notable effect on the property parameter of coal, the samples with different bedding angles are prepared. The effects of bedding on the anisotropic characteristics of the coal seam are investigated. A geological geomechanical model is built based on the geology characteristics of the Jiaozuo coal mine target reservoir to study the effects of bedding on the fracture propagations during hydraulic fracturing. The effects of injection pressure, well completion method, in-situ stress difference coefficient, and fracturing fluid displacement on the fracture propagations are investigated. Results show bedding has notable effects on the property parameters of coal, which is the key factor affecting the anisotropy of coal. The hydraulic cracks trends to bifurcate and swerve at the bedding due to its low strength. Induced fractures are produced easily at the locations around the bedding. The bedding is beneficial to form a complicated fracture network. Experimental and numerical simulations can help to understand the effects of bedding on hydraulic fracturing in coalbed methane reservoirs.