• 한국수정란이식학회지
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• 제33권4호
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• pp.287-296
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• 2018

Ganglioside GM3 is known as an inhibition factor of cell differentiation and proliferation via inhibition of epidermal growth factor receptor (EGFR) phosphorylation. Our previous study showed that the exogenous ganglioside GM3 reduced the meiotic maturation of porcine oocytes and induced apoptosis at 44 h of in vitro maturation (IVM). However, the role of ganglioside GM3 in the relationship between EGFR signaling and apoptosis during porcine oocyte maturation has not yet been studied. First, porcine cumulus-oocyte complexes (COCs) were cultured in the NCSU-23 medium with exogenous ganglioside GM3 according to maturation periods (non-treated, only IVM I: 0 - 22 h, only IVM II: 22 - 44 h and IVM I & II: 0 - 44 h). We confirmed that the proportion of germinal vesicle breakdown (GVBD) increased significantly in the IVM I treated group than in the control group. We also confirmed that the meiotic maturation until M II stage and polar body formation decreased significantly in the only IVM I treated group. Cumulus cell expansion and mRNA levels of the expansion-related factors (HAS2, TNFAIP6 and PTX3) decreased significantly in the IVM I treated group than in the control group. Protein levels of EGFR, p-EGFR, ERK1/2, and p-ERK1/2 decreased significantly in the GM3-treated groups, during the IVM I period. In addition, cellular apoptosis, determined using TUNEL assay, and protein levels of Cleaved caspase 3, were increased significantly in the GM3-treated COCs during the IVM I period. Based on these results, ganglioside GM3 exposure of porcine COCs during the IVM I period reduced meiotic maturation and cumulus cell expansion via inhibition of EGFR activity in pigs.

• 한국발생생물학회:학술대회논문집
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• 한국발생생물학회 2003년도 제3회 국제심포지움 및 학술대회
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• pp.77-77
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• 2003

Coculture of HSC with bone marrow-derived mesenchymal stem cells (BM-MSCs) is one of used methods to increase cell numbers before transplant to the patients. However, because of difficulties to purify HSCs after coculture with BM-MSCs, it needs to develop a method to overcome the problem. In the present study, we have examined whether a culture insert placed over a feeder layer might support the expansion of HSCs within the insert. $CD34^+/ $ cells isolated from the umbilical cord blood by using midiMACS were divided into three groups. A group of 1 $\times$ $10^5$ cells were grown on a culture insert without feeder layer (Direct). The same number of HSCs was directly cocultured with BM-MSCs (Contact). The third group was placed onto an insert below which BM-MSCs were grown (Insert). To distinguish feeder cells from HSCs, BM-MSCs was pre-labeled fluorescently with PKH26 and 1 $\times$ $10^5$ cells were seeded in the culture dishes. After culture for 13 days, the expansion factor (x) of HSCs that were grown without feeder layer (Direct) was $26.6 \pm 8.4.$ In contrast, the number of HSCs directly cocultured with feeder layer was 59.6 $\pm$ 0.5 and that of HSCs cultured onto an insert was $46.9 \pm 8.4.$ The percentage of BM-MSCs cells remained being fluorescent was $97.9 \pm 0.3%$ after culture. Immune-phenotypically large proportion of cultured cells were founded to be differentiated into myeloid/monocyte progenitor cells. The ability of BM-MSCs, fetal lung, cartilage and brain tissue cells to support ex vivo expansion of HSCs was also examined using the insert. After 11 days of coculture with each of these cells, the expansion factor of HSCs was 15.0, 39.0, 32.0 and 24.0, respectively. Based upon these observations, it is concluded that the coculture method using insert is very effective to support ex vivo expansion of HSCs and to eliminate the contamination of other cells used to coculture wth HSCs.

• 공업화학
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• 제21권3호
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• pp.258-264
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• 2010

대형 선박과 발전소 및 화학 공장 등을 구성하는 배관 및 계통은 다양한 구성요소들로 이루어져 있다. 밴드, 티, 급격 확대, 급격축소, 오리피스와 같은 이러한 구성요소들은 시스템 전체의 압력강하를 유발한다. 집중변수모델을 사용하여 구성요소들에 의한 압력손실은 계산할 시에는 압력손실계수인 k-factor가 제공되어야 한다. 일반적으로 많은 공학 분야에서 k-factor의 계산에 Idelchik 모델이 사용되어 왔다. 본 연구에서는 전산유체역학 해석을 통하여 압력손실계수를 계산하고 그 결과를 Idelchik이 제안한 압력손실계수와 비교하였다. 이는 복잡한 유동영역의 압력손실계수 계산에 전산유체역학 코드의 활용성을 검증하기 위함이다. 해석결과, 레이놀즈 응력 모델이 압력손실계수를 가장 잘 예측하고 있다. 전산유체역학을 통한 압력손실계수 평가는 사용된 난류모델에 영향을 받지만 압력손실계수를 잘 예측하고 있으므로 압력손실 계산에 전산유체역학 코드를 사용하는 것은 타당하다고 판단된다.

• 국제지역연구
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• 제13권2호
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• pp.371-392
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• 2009

본 연구의 목적은 국내 전기 전자 기업의 해외진출 정도에 따라 GSCM의 사업성과 결정요인에 대해서 분석하였다. GSCM을 구축한 국내 전기 전자 기업의 72개 기업들을 대상으로 실증분석을 수행하였다. 전기 전자 산업의 GSCM 결정요인으로 프로세스혁신 정보역량 파트너십 등 3개의 요인들로 측정하였으며, 사업성과 요인은 민첩성 요인으로 측정하여 연구모형에 포함시켜 실증분석을 한 결과 다음과 같은 연구결과를 얻었다. 첫째 GSCM의 프로세스혁신은 해외진출 정도가 높을수록 민첩성에 더 큰 영향을 미쳤다. 둘째 GSCM의 정보역량은 해외진출 정도가 높을수록 민첩성에 더 큰 영향을 미쳤다. 셋째 GSCM의 파트너십은 해외진출 정도가 높을수록 민첩성에 더 큰 영향을 미쳤다. 본 연구는 전기 전자 산업의 기업이 해외진출 정도가 높을수록 프로세스혁신 정보역량 파트너십 요인이 사업성과에 더 큰 영향을 미치는 연구결과를 도출하였고 향후 연구로 기업의 규모 해외경험 정도 등의 측면이 연구모형에 반영되어야 하겠다.

• 전기학회논문지P
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• 제67권3호
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• pp.155-159
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• 2018

Recently, the expansion or establishment of facilities for the logistics system is increasing. Conveyor facilities play a major role in sorting and transporting logistics. Induction motors are widely used for the operation of these conveyor systems. In the logistics system, a large number of induction motors are used. These motors have a considerable distance from the power source side and have a low power factor. The installation position for the power factor compensation of the induction motor is very important. Since the voltage drop depends on the length of the line, it is an important parameter in capacitor capacity determination for power factor compensation. The capacity of the capacitors installed to compensate the power factor of the inductive load should be designed to the extent that self-excitation does not occur. In this study, we analyze the method of compensating the proper power factor considering the voltage drop and the installation position of the induction motor in the logistics system.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2009년도 춘계학술대회 논문집
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• pp.320-323
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• 2009

추진기관의 개발과정에서는 추진제의 조성개발, 온도에 따른 성능분석, 내열재 삭마상태 등 여러가지 고려사항이 있다. 노즐 확장비에 따른 추진기관의 성능분석 또한 이러한 과정 중에 하나로 추진기관의 성능을 결정짓는 중요한 요소이다. 추진기관에 대한 해석 후 실제 모타를 제작 시험하여 이를 검증하였다.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 1998년도 추계학술대회 논문집
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• pp.115-120
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• 1998

This paper is especially concerned with the weldment between support beam and square bar that plays important roles in control box of Expansion Joint as a bridge structure. Fatigue strength of the weldment is dependent on notch radius from welding defects and material properties. From which, tensile strength($\sigma$ult) and fatigue notch factor(Kf) become important factors to predict fatigue life. The fatigue notch sensitivity(η) for metals can be divided into two types : high and low notch sensitivity. In this work, the Expansion Joint weldment was found to have low notch sensitivity. Fatigue test of real structure was performed up to 106cycles to be compared with predicted endurance limit.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1990년도 하계학술대회 논문집
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• pp.96-99
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• 1990

Recently, electric energy consumption pattern shows very high peak load with low load factor. This Load pattern have made electric utilities be interested in Load Management, many studies are reported. But most of these studies are concerned with Rate - Load shape relation, a few of these are concerned with generating cost reduction. In this study, the effect of Load Management is incorporated to establish optimal Generation Expansion Planning. Using avoided cost, optimal generation expansion planning is achieved to make maximum avoided cost of Electric utility. Dynamic programming technique is used to solve this algorithm.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2005년도 추계 학술논문 발표대회
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• pp.79-83
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• 2005

In the reinforced concrete structure, Even if speak that water leakage occurrence is no problem to material, there is a lot of reasons construction factor, material damage by behavior structure, properties of matter change by years and water leakage part by environment condition. so, waterproofing technological consideration should be gone ahead. In this research, we will study about stick performance, concrete surface adhesive, damage and blow. we will check all things and test it. The stick expansion type complex of flexible material passed on result of standard. It is conducive to concrete of durability by waterproofing layer performance demobilitation technology on the water leakage structure for solution of problem and repair

• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1993년도 추계학술대회
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• pp.194-197
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• 1993

A technique for fast image reduction or expansion, in which the reduction(expansion) factor is either any integer or any rational number M/L Is represented. The multiresolution is modeled as an interpolation and filtering followed by a decimation. The model enables frequency domain analysts of the muitiresolution representations as well as convenient design of the Kernels(filters). Using any rin linear phase(Type I) filters a fine to coarse multiresolution structure can be generated.