• Journal of the Korean Society of Industry Convergence
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• v.20 no.1
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• pp.67-73
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• 2017

This study aimed to analyze the fluid inside the ceramic filtration dust collection system which was assumed to be a stationary 3-dimensional turbulence. The fluid dynamics data necessary for performance curves were obtained based on the analysis results. The governing equations used to compute the velocity distribution and pressure inside the catalyst converter were expressed with continuity and momentum equations. Furthermore, the ${\kappa}-{\varepsilon}$ turbulence model, already validated by the industry(coal factory, high temperature dust collector) was used for the study. Of a total of three computational models employed, Model-1 served as the basis for CFD analysis which took measurements in increments of 70mm.

• Asian-Australasian Journal of Animal Sciences
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• v.15 no.3
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• pp.326-329
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• 2002

A population of exotic Holstein Friesian, Jersey, their crossbreds and the indigenous Murrah breed of buffalo bulls (n=486), used in artificial insemination breeding program were screened for the allelic distribution of the ${\kappa}$-casein and ${\beta}$-lactoglobulin genotypes. The preferred "B" allele frequency was highest in Murrah buffalo bulls followed by Jersey and Holstein Friesian. The increase in this particular allele frequency in the Holstein Friesian crossbred bulls was more when compared to their Jersey counterparts. Hardy-Weinberg's equilibrium was maintained albeit with some deviations, which was higher in crossbreds than in purebreds. The feasibility of using such large-scale molecular diagnostic tools in the field and their significance with regards to the dairy economy is discussed.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.03a
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• pp.729-731
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• 2008

Three-dimensional unsteady simulation using RNG $\kappa-\varepsilon$ turbulence model is used in full flow passage of model Kaplan turbine. Then the pressure pulsation is obtained. Monitoring data of pressure pulsation in the turbine is obtained through experiment and is compared with the numerical simulation. And a good coherence is shown between the simulation and the experiment. Then the regularity of the pressure pulsation s distribution and transmission in the turbine is discussed in detail.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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• v.25 no.1
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• pp.12-21
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• 2012

Background and Objectives : Allergic rhinitis is one of the most common diseases in the otorhinolaryngology area. in oriental clinic, Hyunggaeyungyo-tang(HYT) has been used as a primary prescription to treat allergic rhinitis. However, there have been no studies so far performed on the effect of this HYT use. The purpose of this study was find out therapeutic effects of its exclusive use on the rat with allergic rhinitis. Material and Methods : Thirty BALB/c mice were divided into three group : normal group(NOR), control group(CON) inoculated with allergic rhinitis and sample group(SAM) treated with the HYT extract after it was treated the same as the control group. Rats were sensitized intraperitoneally with ovalbumin solution 4times at intervals of 2 days. After that time, rats in SAM were administered by HYT to treat the inflammation. Results : 1. The number of eosinophil in SAM noticeably decreased than CON and this decrease had probability. The inhibition of eosinophil distribution. The infiltration of eosinophil in SAM noticeably decreased than CON. 2. The damaged mucosa as disruption of cilia in respiratory cell, vacant mucose secreting cell and infiltration of inflammation intricate cells in CON were increased than NOR, but SAM same as normal configuration. Decrease of icthing and sneezing intricate neurotransmitter (substance P). Decrease of angiogenesis intricate cytokine(MIP-2). 3. Transcription factor(NF-${\kappa}B$ p65) was decreased. 4. Transcription factor inhibitor(p-$I{\kappa}B$) was decreased. 5. Inflammation cytokine(iNOS) was decreased. Conclusion : The results suggest that HYT is significantly effective in the treatment of inflammation caused by allergic rhinitis through the suppression of NF-${\kappa}B$ activation and iNOS production.

• Journal of the Korean Society for Heat Treatment
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• v.17 no.6
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• pp.346-355
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• 2004

The flame quenching process has been employed to modify the surfaces of commercial marine propeller material, aluminum bronze alloy (Cu-8.8Al-5Ni-5Fe), and the microstructure, hardness and wear properties of the flame-quenched layers have been studied. The thermal history was accurately monitored during the process with respect to both the designed maximum surface temperature and holding time. The XRD and EDX analyses have shown that at temperatures above $T_{\beta}$, the microstructure consisting of ${\alpha}+{\kappa}$ phases changed into the ${\alpha}+{\beta}^{\prime}$ martensite due to an eutectoid reaction of ${\alpha}+{\kappa}{\rightarrow}{\beta}$ and a martensitic transformation of ${\beta}{\rightarrow}{\beta}^{\prime}$. The ${\beta}^{\prime}$ martensite phase formed showed a face-centered cubic (FCC) crystal structure with the typical twinned structure. The hardness of the flame-quenched layer having the ${\alpha}+{\beta}^{\prime}$ structure was similar to that of the ${\alpha}+{\kappa}$ structure and depended sensitively on the size and distribution of hard ${\kappa}$ and ${\beta}^{\prime}$ phases with depth from the surface. As a result of the sliding wear test, the wear resistance of the flame-quenched layer was markedly enhanced with the formation of the ${\beta}^{\prime}$ martensite.

• Journal of the Korean Society of Propulsion Engineers
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• v.6 no.1
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• pp.1-11
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• 2002

The suitable turbulence model is found to be required in the course of establishing a proper analysis methodology for thermal stripping phenomena which are shown in strong temperature variation area such as reactors and propulsion devices. Three different turbulence models of $\kappa$-$\varepsilon$ model, modified $\kappa$-$\varepsilon$ model, and full Reynolds stress(FRS) model, are applied to analyze unsteady turbulent flows with temperature variation. Three test cases are selected for verification. These are vertical jet flows with water and sodium, and parallel jet flow with sodium. Analysis yields the conclusion that 3-D computation with FRS betters others. However, modified modeling is required to improve its heat transfer characteristic analysis. Further analysis is performed to find momentum variation effects on temperature distribution. It is found that the momentum increase results increase of fluid mixing and magnitude of temperature variation.

• Proceedings of the Korea Water Resources Association Conference
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• 2015.05a
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• pp.168-168
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• 2015

자연하천의 주요한 특징 중 하나인 하천의 사행은 직선수로에서 예측되는 유속분포를 왜곡시키며 매우 복잡한 흐름구조를 형성한다. 이는 하상 경계면에서 발생하는 전단응력 분포의 변화를 야기하는데 하상 경계면에서의 전단응력은 다양한 경험적 관계에 의존하는 유사이동의 한계 소류력 산정 및 오염물질 거동해석의 분산계수 산정에 많은 영향을 미치게 된다. 물리적인 관측을 통한 하상 경계면에서의 전단응력의 관측은 다소 제한적이며 많은 비용을 요구한다. 따라서 하상 경계면에서 발생하는 전단응력의 경우 수심의 20% 이하의 연직 유속분포를 벽법칙에 적용하여 추정하는 방법이 주로 이루어지고 있다. 벽법칙을 이용한 하상 경계면의 전단응력을 계산하는 경우 대수중복층의 유속 분포 $u/u^*=(1/{\kappa})ln(zu^*/{\nu})+B$에서 무차원상수 ${\kappa}$와 B의 적절한 추정이 요구되어 진다. 일반적으로 무차원상수 ${\kappa}$와 B는 수리학적으로 매끄러운 벽면에서 대략 ${\kappa}=0.4$, B=5.5로서 경험적으로 이용되고 있다. 본 연구에서는 직선수로 및 다양한 사행수로의 3차원 흐름장 모의를 수행하여 벽법칙의 대수 중복층을 따르는 주흐름 방향 유속의 연직분포를 비교하였다. 수치모의 소프트웨어로서 Linux 기반의 OpenFOAM이 사용되었으며 모델의 검증을 위해 Chang(1971)에 의해 수행 된 사행수로에서의 유속장 관측 결과와 비교하였고 수치모의 결과가 실험 관측치와 잘 일치하는 것으로 판단되었다. 수치모의에 적용 된 사행수로의 형상은 Hey(1976)에 의해 제안 된 사행하천의 지형학적 인자들 간에 관계를 이용하여 사행도 1.03에서 2.42까지 총 7개의 사행수로 지형을 생성하였다. 사행도의 변화에 따라 만곡부 정점에서 대수중복층 구간의 주흐름 방향 유속의 연직분포를 비교한 결과, 본 연구에서 생성 된 모든 사행수로에서 대수중복층 구간의 무차원 유속 $u^+$와 무차원 거리 $z^+$가 로그 분포를 따르는 것으로 나타났으나 경험적으로 사용되었던 무차원상수 B의 경우 사행도가 증가 할수록 대수적으로 감소하는 경향이 나타났다. 본 연구에서는 이러한 관계가 무차원 상수 B값에 미치는 영향을 반영하여 수리학적으로 매끄러운 벽면에서 적용이 가능한 수정된 대수중복층 식을 제시하고자 한다.

• The Journal of Korean Medicine
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• v.29 no.1
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• pp.179-191
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• 2008

Background and Objectives : Atopic dermatitis is a recurrent or chronic eczematous skin disease with severe pruritus,and has increased in Korea. Although the pathogenic mechanisms of atopic dermatitis are yet unknown, recently skin barrier dysfunction and hyperresponsive Th2 cells in the acute phase have been reported as important mechanisms. Cheonggi-san(CGS) is used in oriental clinics for treatingacute skin lesions of eczema or urticaria. There have been no studies on the therapeutic mechanism of CGS for curing atopic dermatitis. We aimed to find out the therapeutic effects of its internaluse on atopic dermatitis-like skin lesions, induced in NC/Nga mice by the mite antigen D. pteronyssinus and disrupting skin barrier. Materials and Methods : The NC/Nga mice were classified into three groups: control group, atopic dermatitis elicitated group(AD), and CGS treated group (CT). Atopic dermatitis-like skin lesions were induced on the back of female NC/Nga mice, 12 weeks of age, by tape stripping, 5% SDS applied to disrupt skin barrier and painting 3 times a week with D. pteronyssinus crude extract solution for 3 weeks. CT was treated with CGS orally after atopic dermatitis was elicitated. We observed changes of skin damage, mast cells, substance P, angiogenesis, skin barrier, Th2 cell differentiation, nuclear factor-${\kappa}B(NF-{\kappa}B)$ p65 activation and COX-2 in NC/Nga mice with atopic dermatitis-like skin lesions. Results : The skin damages as eczema were seenin AD, but mitigated in CT. The degranulated mast cells in dermal papillae increased in AD, but decreased in CT. The substance P positive reacted cells in CT remarkably decreased. The angiogenesis increased in AD, but decreased in CT. The decrease of lipid deposition and ceramide in AD was seen, but anincrease of lipid deposition and ceramide in CT was seen. The distribution of IL-4 positive reacted cells in dermal papillae increased in AD, but decreased in CT. The distribution of NF-${\kappa}B$ p65 positive reacted cells & COX-2 positive reacted cells in CT decreased. Conclusion : The results may suggest that the CGS per os decreases the dysfunction of the skin barrier, inhibits Th2 cell differentiation and inhibits NF-${\kappa}B$ p65 activation in NC/Nga mice with atopic dermatitis-like skin lesions.

• Solar Energy
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• v.17 no.3
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• pp.3-11
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• 1997

Recently the construction of atrium buildings has increased but along with it many problems in thermal environment have arised. since the exterior wall of glass, indoor temperature is greatly influenced by weather conditions and since the space volume is very large, the vertical air temperature is not uniform. So, in this study, a Vertical Temperature Distribution Model was developed to predict the vertical air temperature of an atrium and evaluate the effects of the design parameters on the air temperature distribution of an atrium. To consider the characteristics of the vertical air temperature distribution in an atrium, the Satosh Togari's Macroscopic Model was used basically for the calculation of the vertical air temperature distribution in large space and the solar radiation analysis model and natural ventilation analysis model in atrium. And to calculate the unsteady-state inside wall surface temperature(boundary condition), the finite difference method was used. For the verification of the developed temperature distribution program, numerical evaluation of air flow by the ${\kappa}-{\varepsilon}$ turbulence model and in-situ test was conducted in parallel. The results of this study, the developed temperature distribution program was seen to predict the thermal condition of the atrium very accurately.

• 한국연소학회:학술대회논문집
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• 2004.06a
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• pp.192-198
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• 2004

A numerical study was conducted to determine the effects of high temperature air, including equivalent ratio on flow field, temperature, evaporation, and overall temperature distribution in gas turbine combustor. A sector model of a typical wall jet can combustor, featuring introduction of primary air and dilution air via wall jet, was used in calculations. Flow field and temperature distribution were analyzed. Operating conditions such as inlet temperature and overall equivalent ratio were varied from 373 to 1300 K, and from 0.3 to 0.6, respectively, while any other operating conditions were fixed. The RNG ${\kappa}-{\varepsilon}$ model and eddy breakup model were used for turbulence and combustion model respectively. It was found that the increase with the inlet air temperature, velocity in the combustor is accelerated and evaporation of liquid fuel is not affected in primary zone, high temperature inlet air enhances the evaporation and improves overall temperature distribution factor.