• Proceedings of the Korean Nuclear Society Conference
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• 1997.05a
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• pp.606-610
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• 1997

울진 원전 3,4 호기 확률론적 안전성 평가 (PSA) 모델을 risk monitor 모델로 변환하여 한국원자력연구소에서 개발한 risk monitor인 Risk Monster[1]에 설치하였으며 이를 이용하여 필수냉각수 계통(ESW;Essential Service Water) 펌프의 가동중 정비(on-line maintenance)의 가능성 여부를 연구하였다. ESW 펌프를 가동중 정비하더라도 안전성 측면에서 별 문제가 없으며 경제성 여부는 보다 정확한 검토가 요구되나 상당히 있는 것으로 판단된다. 한편 ESW펌프 한대의 고장이 원전 가동중에 미치는 위험도를 분석하였으며 그 결과 ESW펌프 한대의 고장에도 불구하고 원전 계속 가동에는 큰 문제가 없었다.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2008.05a
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• pp.439-443
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• 2008

We investigate the mechanical behavior of a pre-heat treated steel of ESW95, which is being used for automotive parts including tie-rods to save manufacturing cost and enhance product quality. SCM435 is also investigated to reveal the characteristics of the pre-heat treated steel tested. AFDEX/MAT is used to extract the true stress-strain curve over the large strain with higher accuracy. It has been found that ESW95 has very week strain-hardening behavior which can be negligible compared with SCM435 and that the initial yield strength is quite high and the toughness of ESW95 reaches nearly 75% of SCM435. ESW95 is characterized by the weak strain-hardening behavior and high yield strength that can be lead to minimization of post-processing including heat treatment and straightening. ESW95 and SCM435 are also compared by applying them to ball-stud forging by computer simulation. It is expected that a great deal of change may take place in production as well as in service if the pre-heated steels are adopted.

• Proceedings of the KWS Conference
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• 1996.10a
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• pp.129-132
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• 1996

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.1123-1124
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• 2011

본 논문에서는 ESW(Electro slag welding)의 용접을 위한 해석을 수행하였다. 특히, 열전달 해석을 통하여 부재내부에 발생하는 온도분포에 대한 해석을 수행하였으며, 이를 입력조건으로 하여 구조해석을 수행함으로써, 최종적은 부재내의 최고온도와 최대 변형량을 구할 수 있었다.

• Tuberculosis and Respiratory Diseases
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• v.45 no.5
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• pp.992-999
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• 1998

Background: To correlate the emphysema score for quantification of the overall extent of emphysema in both lungs by CT with physiologic fingings and to get more objective and simple method to assess the extent of emphysema. Method: Thin-section CT and pulmonary function test(PFT) were performed in 17 patients with emphysema (all males, mean age, 62 years). Emphysema score was obtained as percentage of emphysematous lung area, dividing the total area of the emphysema(voxels with attenuation value less than -880, -900, -920HU, respectively) by the overall area of both lungs(voxels with attenuation value less than -400HU) with highlighting voxels using "Density mask" program. Emphysema score was calculated from whole lung(ESV) and 5 representative scans(ESR) using "Density mask", Visual emphysema score(ESV) was obtained by visual assessment from 5 representative scans. Correlation of these emphysema scores(ESW, ESR, ESV) and physiologic findings were performed, comparing the ESW with ESR and ESV. Results: ESW had correlation with DLCO(r=0.53-0.64) and $FEV_1/FVC$(r=0.42-0.57) among PFT parameters. ESR had good correlation with ESW and with PFT parameters as well. ESV did not correlate with PFT parameters except DLCO. Conclusion: CT quantification of emphysema using "density mask" correlated well with physiologic findings. To assess the severity of emphysema, both ESW and ESR are more reliable than ESV, and ESR is recommended in routine practice as it is objective, simple and reliable.

• Transactions of Materials Processing
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• v.29 no.1
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• pp.20-26
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• 2020

In the design of the metal forming processes, various types of ductile fracture criteria are used to predict crack initiation and to fabricate metallic products without any defects. However, the quantitative measurement method for determination of crack initiation is insufficient. It is very difficult to detect crack initiation in ductile metals with excellent deformability because no significant load drop is observed due to crack generation. In this study, the applicability of acoustic emission sensors, which are commonly used in facility diagnostics, to measure crack initiation during the metal forming process was analyzed. Cylindrical notch specimens were designed using the finite element method to induce a premature crack on the surface of pre heat-treated steel (ESW90) material. In addition, specimens with various notch angles and heights were prepared and compression tests were carried out. During the compression tests, acoustic emission signal on the dies and images of the surface of the notch specimen were recorded using an optical camera in real time. The experimental results revealed that the acoustic emission sensor can be used to detect crack initiation in ductile metals due to severe plastic deformation.

• Transactions of Materials Processing
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• v.18 no.6
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• pp.453-457
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• 2009

In this paper, plastic deformation behaviors of ESW105 and SCM435 steels are revealed by simulations and experiments. ESW105 is the special pre-heat-treated steel characterized by high initial yield strength and negligible strain-hardening behavior. The flow stresses of the two steels for large stain are calculated from tensile tests. Axial and lateral compressions of cylindrical bars are tested and simulated and the deformed shapes are compared to characterize the plastic deformation behaviors of the two materials. A forward extrusion process of a cylindrical bar is also simulated to reveal the difference. It has been shown that there are pretty much difference in plastic flow between ESW105 and SCM435 which causes from the difference in strain-hardening capability, implying that the experience-oriented design rules for common commercial materials may lead to failure in process design when the new material of ESW105 is applied without consideration of its plastic deformation behavior.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2009.05a
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• pp.48-51
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• 2009

In this paper, plastic deformation behaviors of ESW105 and SCM435 steels are revealed by simulations and experiments. ESW105 is the special pre-heat-treated steel characterized by high initial yield strength and negligible strain-hardening behavior. The flow stresses of the two steels for large stain are calculated from tensile tests. Axial and lateral compressions of cylindrical bars are tested and simulated and the deformed shapes are compared to characterize the plastic deformation behaviors of the two materials. A forward extrusion process of a cylindrical bar is also simulated to reveal the difference. It has been shown that there are pretty much difference in plastic flow between ESW105 and SCM435 which causes from the difference in strain-hardening capability, implying that the experience-oriented design rules for common commercial materials may lead to failure in process design when the new material of ESW105 is applied without consideration of its plastic deformation behavior.

• Journal of the Korean Society of Safety
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• v.12 no.4
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• pp.21-26
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• 1997

Korea Atomic Energy Research Institute (KAERI) developed a risk monitor called Risk Monster which supports for plant operators and maintenance schedulers to monitor plant risk and to avoid high peak risk by rearranging maintenance work schedule. Risk Monster can update the plant risk continuously according to the change of system/component configuration since Risk Monster reevaluates the plant risk based on the Probabilistic Safety Assessment (PSA) results. A brief description of Risk Monster is provided. The PSA model of UCN 3, 4 nuclear power plant was converted by KAERI to Risk Monster model. Using this Risk Monster model, a feasibility study of the on-line maintenance of an Essential Service Water (ESW) pump was performed. On-line maintenance of one ESW pump has been shown to be acceptably safe, and has economic benefits. In addition, it is not a violation of technical specification to continue plant operation with an out-of-service ESW pump.

• Journal of the Korean Society of Food Science and Nutrition
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• v.40 no.4
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• pp.486-492
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• 2011

This study was designed to evaluate the effect of hot water extract (ESW) and 70% ethanol extract (ESE) from Euphorbia supina Rafin on LPS-stimulated inflammatory response in RAW 264.7 macrophages. Upon investigation at concentrations up to $1000\;{\mu}g$/mL, ESW and ESE did not have any cytotoxic effects on RAW 264.7 macrophages. ESW induced inhibition of 21.6%~54.8% of nitric oxide (NO) production at 100~1000${\mu}g$/mL, and $PGE_2$ production was inhibited up to 25.7%~38.2% at 250~1000${\mu}g$/mL, proportional to the ESW concentrations. ESW induced inhibition of 66.1% and 54.3% of IL-6 production at 250 and $1000\;{\mu}g$/mL, respectively. ESE (100~1000${\mu}g$/mL) induced inhibition of 38.3%~77.5% of NO, 40%~94.7% of $PGE_2$, and 43.9%~89.4% of IL-6 production, proportional to the ESE concentrations. Only 44.1% of IL-10 production was inhibited at a concentration of $500\;{\mu}g$/mL. ESE induced an increase in TNF-${\alpha}$ production at a concentration of 100 and $250\;{\mu}g$/mL, whereas at high concentrations (500 and $1000\;{\mu}g$/mL), ESE induced inhibition of 19.2% and 92.4% of TNF-${\alpha}$ production, respectively. In conclusion, concentrations of more than $500\;{\mu}g$/mL ESE demonstrated effective immune-modulating activity through inhibition of NO, $PGE_2$, IL-6, IL-10, or TNF-${\alpha}$ production, as it relates to the macrophage's immuno-activity; therefore, ESE has potential as a good candidate substance for reduction of inflammatory responses.