• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.27 no.9
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• pp.1-5
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• 2013

We developed high-efficient 6W-LED package with simple structure by applying Heat Slug and silicone-reflector. LED package was manufactured in $8.5{\times}8.5mm$ sized multi-chip structure having thickness of $500{\mu}m$ achieved by bonding silicon-reflector with prepreg on top of the plate after implementing the reflector placed on copper substrate Half Etching by thickness of $200{\mu}m$. The luminous flux, luminous efficacy, correlated color temperature, color rendering index and thermal resistance of developed LED was evaluated, and it verified the application of products by applying it to 120W-LED road luminaires through simulation. The luminous efficacy of LED package reached over 130lm/W, and it is possible to be manufactured into 120W-LED road luminaires using 18 packages. In addition, the simulation results showed average of horizontal illuminance and overall illuminance uniformity that is suitable for three-lane road.

• Archives of Metallurgy and Materials
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• v.65 no.3
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• pp.1035-1039
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• 2020

U-10wt.%Zr-5wt.%RE fuel slugs for a sodium-cooled fast reactor (SFR) were conventionally prepared by a modified injection casting method, which had the drawback of a low fabrication yield rate of approximately 60% because of the formation of many metallic fuel scraps, such as melt residue and unsuitable fuel slug butts. Moreover, the metallic fuel scraps were classified as a radioactive waste and stored in temporary storage without recycling. It is necessary to develop a recycling process technology for scrap wastes in order to reduce the radioactive wastes of the fuel scraps and improve the fabrication yield of the fuel slugs. In this study, the additive recycling process of the metallic fuel scraps was introduced to re-fabricate the U-10wt.%Zr-5wt.%RE fuel slugs. The U-10wt.%Zr-5wt.%RE fuel scraps were cleaned on the surface impurity layers with a mechanical treatment that used an electric brush under an Ar atmosphere. The U-10wt.%Zr-5wt.%RE fuel slugs were soundly re-fabricated and examined to evaluate the feasibility of the additive process compared with the metallic fuel slugs that used pure metals.

• The Journal of Engineering Geology
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• v.11 no.1
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• pp.63-79
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• 2001

This study is aimed for estimating hydraulic parameters using the Cooper-Bredehoeft-Papadopulos, the Hvorslev, and the Bouwer & Rice methods at nineteen test holes in Me. Geumjeong area composed of Bulguksa granites, and for characterizing hydraulic properties at the test holes with relatioll to drill core data. The relation among hydraulic Dammeters obtained by the three methods is also considered. The study area is divided into four sub-areas to consider the hydraulic characteristics. The difference of hydraulic conductivity estimates between the injection and the withdrawal slug test may be due to penncable fracture distlibutions around the test hole and/or the disturbance of fine mateIials in the fractures induced by the pressure variation due to different mechanisms of test initiation. The hydraulic conductivity estimates detennined by the Cooper-Bredehoeft-Papadopulos, the Hvorslev and the Bouwer & Rice methods ranges from 10$^{-8}$ to lO$^{-5}$m/sec, and the ranges of average values are from 10$^{-7}$ to 10$^{-6}$m/sec. Also, the transmissivity ranges from 10$^{-7}$ to 10$^{-5}$$m^2$/sec. Comparing average hydraulic conductivity by the Cooper-Bredehoeft-Papadopulos, the Hvorslev and the Bouwer & Rice methods, by the Hvorslev method has the highest values, then the Bouwer & Rice method, and the Cooper-Bredehoeft-Papadopulos method has the lowest.

• Journal of Korean Society of Environmental Engineers
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• v.30 no.9
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• pp.948-954
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• 2008

Membrane bioreactor(MBR) processes have been widely applied to wastewater treatment for last decades due to its excellent capability of solid-liquid separation. However, membrane fouling was considered as a limiting factor in wide application of the MBR process. Excess aeration into membrane surface is a common way to control membrane fouling in most MBR. However, the excessively supplied air is easily dissipated in the reactor, which results in consuming energy and thus, it should be modified for effective control of membrane fouling. In this study, cylindrical tube was introduced to MBR in order to use the supplied air effectively. Membrane fibers were immersed into the cylindrical tube. This makes the supplied air non-dissipated in the reactor so that membrane fouling could be controlled economically. Two different air supplying method was employed and compared each other; nozzle and porous diffuser which were located just beneath the membrane module. Transmembrane pressure(TMP) was monitored as a function of airflow rate, flux, and ratio of the tube area and cross-sectioned area of membrane fibers(A$_m$/A$_t$). Flow rate of air and liquid was regulated to obtain slug flow in the cylindrical tube. With the same flow of air supply, nozzle was more effective for controlling membrane fouling than porous diffuser. Accumulation of sludge was observed in the tube with the nozzle, if the air was not suppled sufficiently. Reduction of membrane fouling was dependent upon the ratio, A$_m$/A$_t$. For diffuser, membrane fouling was minimized when A$_m$/A$_t$ was 0.27, but 0.55 for nozzle.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.9
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• pp.4065-4069
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• 2015

Background: Epidermal growth factor-like domain multiple 7 (EGFL7), a secreted protein specifically expressed by endothelial cells during embryogenesis, recently was identified as a critical gene in tumor metastasis. Epithelial-mesenchymal transition (EMT) was found to be closely related with tumor progression. Accordingly, it is important to investigate the migration and EMT change after knock-down of EGFL7 gene expression in human pancreatic cancer cells. Materials and Methods: EGFL7 expression was firstly testified in 4 pancreatic cancer cell lines by real-time polymerase chain reaction (Real-time PCR) and western blot, and the highest expression of EGFL7 was found in PANC-1 cell line. Then, PANC-1 cells transfected with small interference RNA (siRNA) of EGFL7 using plasmid vector were named si-PANC-1, while transfected with negative control plasmid vector were called NC-PANC-1. Transwell assay was used to analyze the migration of PANC-1 cells. Real-time PCR and western blotting were used to detect the expression change of EGFL7 gene, EMT markers like E-Cadherin, N-Cadherin, Vimentin, Fibronectin and transcription factors like snail, slug in PANC-1, NCPANC-1, and si-PANC-1 cells, respectively. Results: After successful plasmid transfection, EGFL7 gene were dramatically knock-down by RNA interference in si-PANC-1 group. Meanwhile, migration ability decreased significantly, compared with PANC-1 and NC-PANC-1 group. Meanwhile, the expression of epithelial phenotype marker E-Cadherin increased and that of mesenchymal phenotype markers N-Cadherin, Vimentin, Fibronectin dramatically decreased in si-PANC-1 group, indicating a reversion of EMT. Also, transcription factors snail and slug decreased significantly after RNA interference. Conclusions: Current study suggested that highly-expressed EGFL7 promotes migration of PANC-1 cells and acts through transcription factors snail and slug to induce EMT, and further study is needed to confirm this issue.

• Journal of the KSME
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• v.28 no.3
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• pp.270-280
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• 1988

증기폭발현상에 대한 기존의 연구내용들이 개괄적으로 소개되었다. 지난 30여년간 대규모 및 소규모 증기폭발에 대해 수많은 이론 및 실험적 연구가 진행되어 왔으나 아직 많은 과제들이 미해결의 상태로 남아 있다. 이들은 (1) 연료-냉각수 접촉양식의 영향 (2) 초기 혼합과정에 대한 에너지 전달 및 유동해석 (3) 연료파괴 과정에 대한 정량적 해석 (4) 폭발과정의 전파에 대한 제인자의 영향 (5) 팽창과정 중 슬러그(slug)의 영향 등이며 현상 자체의 난이성과 위 험성에 비추어 볼 때 해석에 많은 문제점을 안고 있다. 그러나 과학적인 호기심과 더불어 산 업재해 방지 및 현상의 생산적 이용이라는 최종목표에 도달하기 위해서는 체계적으로 집중적인 연구가 꾸준히 계속되어야 할 것이다.

• Proceedings of the Korean Nuclear Society Conference
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• 2004.10a
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• pp.221-222
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• 2004

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2003.09a
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• pp.536-539
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• 2003

This study area has been contaminated by oils. To identify contaminated ranges and to assess the possibility of contamination dispersion, monitoring wells were installed and slug test, field soil permeability test, automatic or manual measurement of groundwater table, and groundwater quality analyses in field and laboratory were performed. In addition, a groundwater modeling program was used to assess the possibility of oil contamination dispersion, based on field data and groundwater quality data. The results showed that concentration of oil contaminants in groundwater have been decreased by dispersion and adsorption.

• Journal of Advanced Marine Engineering and Technology
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• v.27 no.3
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• pp.460-465
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• 2003

Microgravity experiments were conducted to determine the effect of liquid and gas superficial velocities on flow behaviors. Flow behaviors observed under microgravity conditions can be classified into five flow patterns: bubble. Taylor bubble, slug, semi-annular and annular flows. Transition boundary between four flow patterns could be determined by drift-flux model. It was also found that the effect of gravity and pipe inclination on flow pattern transition was not significant in the inertia dominant region.

• Proceedings of the Korean Nuclear Society Conference
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• 1998.05a
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• pp.731-737
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• 1998

차세대원자로의 붕산희석사고시 노심에 유입되는 저농도 붕산수 slug의 혼합현상에 대한 해석을 수행하였다. FLUENT V4.47을 이용하여 inherent event와 external event로 분류되는 SBLOCA시와 SIS 주입에 따른 급속붕산희석현상에 대해 인차원 축대칭을 가정하여 해석을 수행하였다. 각각의 경우에 대하여 사고시 노심에 추가되는 정반응도는 1.86 %$\Delta$$\rho$ 이하로 계산되었으며, 이 결과는 원자로정지여유도 6.5 %$\Delta$$\rho$다 작은 값을 가지므로 원자로의 안전성을 유지하기에 충분한 여유를 갖는 것으로 해석되었다.