• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집D
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• pp.903-908
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• 2001

A web-based client/server program, MOVIDIK(Motor-Operated-Valve Integrated Database Information of KEPCO) has been developed to perform a design basis safety evaluation for a motor-operated-valve(MOV) in the nuclear power plant. The MOVIDIK consists of seven analysis modules and one administrative module. The analysis module calculates a differential pressure on the valve disk, thrust/torque acting at a valve stem, maximum allowable stress, thermal-overload-relay selection, voltage degradation, actuator output and margin. In addition, the administrative module manages user information, approval system and code information. MOVIDIK controls a huge amount of evaluation data and piles up the safety information of safety-related MOV. The MOVIDIK will improve the efficiency of safety evaluation work and standardize the analysis process for the MOV.

• 한국환경보건학회지
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• 제48권6호
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• pp.324-330
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• 2022

Background: Lung injuries due to exposure to humidifier disinfectants (HDs) were reported in 2011 in South Korea. As a result of the government's epidemiological investigation and toxicity test study, it was found that HDs caused health damage such as lung disease. Objectives: The purpose of this study was to classify HD exposure ratings and analyze the affecting factors that could identify the relationship with lung disease. Methods: Exposure assessment for HDs was conducted using a questionnaire during face-to-face interviews with the applicants. Ratings of high exposure (Class 1) and low exposure (Class 2) were cross-tabulated with clinical ratings (acceptable and unacceptable). Logistic regression analysis was carried out by setting the clinical rating of lung disease as a dependent variable and the socio-demographic and exposure characteristics obtained through the questionnaire as independent variables. Results: The concentration in air of polyhexamethylene guanidine (PHMG) was 71.96±107.47 ㎍/m³, and the exposure concentration was 15.21±23.28 ㎍/m³ . The exposure rating was overestimated with 97.1% of affected subjects having high exposure using margin of exposure (MOE), but only 9.9% matching the clinical class. In the overestimated group, it could be explained by the fact that the exposure time was long and the subjects had already recovered from damage symptoms. As a result of logistic regression analysis, ten variables were found to be significant influencing factors. Conclusions: A new exposure rating could be calculated based on the MOE, and factors affecting lung disease could be estimated through comparative evaluation with the clinical rating.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1992년도 봄 학술발표회 논문집
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• pp.131-136
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• 1992

Eight singly reinforced high strength concrete beams without web reinforcement were tested to investigate their behavior and to determine their ultimate shear capacities. In this study, the main variable was the ration of longitudinal reinforcement. Test results were compared with strength predicted by using ACI code, Zsutty's dquation and Bazant & Kim's equation. As the result, for the beams of low steel ratio, the margin of safety in ACI code may be disappeared. It was shown that Zsutty.s equation well predict the trend of the test data.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2010년도 추계학술대회
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• pp.215-217
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• 2010

This paper describes the test results of radiated compatibility with Ariane 5 launcher performed on the COMS Satellite test facility. Firstly, the Radiated Emission test results are analyzed in compliance with the Radiated Susceptibility requirement specification of Ariane 5 launcher. The satellite nominal operation is monitored during injection a radiated electric field corresponding to the launcher emissions levels in critical frequency ranges. And also, E-field are measured through a probe located at external units level in order to assess the EMC safety margin in Radiated mode.

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 1997년도 춘계학술발표회논문집(1)
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• pp.489-494
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• 1997

A comparative transient analyses were performed for oxide and nitride cores or a large (3000 MWt), pool-type, liquid-metal-cooled reactor (LMR). The study was focused on three representative accident initiators with failure to scram : the unprotected loss-of-flow (ULOF), the unprotected transient overpower (UTOP), and the unprotected fast transient overpower (UFTOP). The margins to fuel melting and sodium boiling have been evaluated for these representative transients. The results show that there is an increase in safety margin with nitride core which maintains the physical dimensions of the oxide core.

• 한국지반환경공학회 논문집
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• 제17권12호
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• pp.55-64
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• 2016

본 논문에서는 기존의 허용응력설계법(ASD)과 신뢰성해석에 기반을 둔 하중저항계수설계법(LRFD)과 유로코드의 부분안전계수설계법(PSFD)을 사용하여 풍화토지반 얕은기초의 전단파괴에 대한 지지력과 안전여유 산정결과에 대하여 비교 분석하였다. 얕은기초의 지지력에 영향을 주는 지반정수의 불확실성을 정량화하기 위하여 시공 및 설계용 평판재하시험 자료를 수집하고 확률 통계 분석을 통하여 극한지지력의 저항편향계수와 변동계수를 조사하였다. 국내 현장의 얕은기초 대표 단면 예에 대한 신뢰성해석(FORM)을 통하여 신뢰도지수를 구하고 지반정수의 확률변수가 전단파괴에 미치는 영향을 조사하기 위하여 확률변수의 민감도 분석을 하였다. ASD설계법, ASD설계법의 안전율에 대응하는 목표신뢰도 지수의 LRFD설계법, PSFD설계법을 사용하여 얕은기초 대표단면의 안정성 검토를 실시하여 산정된 각 설계법의 안전여유에 대하여 비교 검토를 실시하였다.

• 한국방사성폐기물학회:학술대회논문집
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• 한국방사성폐기물학회 2018년도 추계학술논문요약집
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• pp.157-158
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• 2018

In this work, we developed a customized shielded cask transport system which is equipped with a railguided travelling unit and a position adjustment unit for the cask without any crane service. The designed solid model was verified to have sufficient safety margin by using structural analysis. The developed system was introduced to a hot-cell and successfully tested and verified to have required target performance.

• 한국잡초학회지
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• 제30권1호
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• pp.1-16
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• 2010

농경지에 발생하는 주요 잡초에 대한 유묘기 검색방법을 개발하기 위하여 주요 잡초 60종에 대한 양적, 질적형질을 조사하였다. 잡초 유묘를 동정하는 형질로는 질적형질이 양적형질에 비해 보다 더 유용하였다. 자엽의 형태는 타원형과 광타원형이 가장 많았다. 차풀과 큰메꽃은 자엽의 형태가 넓은 직사각형이었다. 자엽의 형태가 횡광타원형인 초종은 4종이었다. 취명아주 등 22종의 잡초는 자엽의 형태가 1개 이상이었다. 이 중 자엽의 형태가 3가지 이상인 초종은 4종으로서 마디풀과의 참소리쟁이와 여뀌 그리고 대극과의 애기땅빈대와 깨풀이었다. 새팥은 자엽이 지면아래의 종자 속에 남아 있었다. 자엽의 엽두는 원두가 가장 많았다. 자엽의 엽저는 쐐기저가 가장 많았다. 환삼덩굴과 마디풀은 자엽의 엽저가 무엽병저였다. 일부 초종은 제 1본엽기와 제 2본엽기때 본엽의 형태가 각각 상이한 경우도 있었다. 돌콩, 새팥 및 매듭풀은 제 1본엽이 각각 광란형, 심장형, 원형 또는 광도란형이었나 제 2본엽에서는 3초종 모두 3출엽으로 전개되었다. 그리고 자귀풀과 차풀은 제 1, 2본엽의 형태가 우수우상복엽이었다. 본엽의 가장자리는 주로 전연이었으나, 큰도꼬마리를 포함한 6종은 제 1, 2본엽의 엽연이 치상거치였다. 애기땅빈대는 제 1본엽의 엽연이 전연, 제 2본엽의 엽연이 치상거치였다. 명아주과의 흰명아주와 좀명아주의 엽연은 제 1본엽기에는 전연, 제 2본엽기에는 불규칙거치였다. 잡초 유묘 자엽의 양적형질은 질적형질에 비해 종 동정 시 활용도는 떨어지나 초종에 따라서는 매우 유용한 경우도 있었다. 농경지 주요 광엽잡초 유묘에 대한 자엽 및 본엽의 질적 형질을 이용하여 간이 식별법을 제시하였다. 식법법 작성 시 자엽의 형태가 1개 이상인 잡초종에 대해서는 각각의 자엽 형태를 이용하여 종 동정이 가능하도록 하였다.

• 한국안전학회지
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• 제26권6호
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• pp.13-19
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• 2011

The purpose of this study is to examine the cause of damage to electrolytic capacitors and to present the heat generation mechanism in order to prevent the occurrence of similar problems. From the analysis results of electrolytic capacitors collected from accident sites, the fire causing area can be limited to the primary power supply for the initial accident. From the tests performed by applying overvoltage, surge, etc., it is thought that the fuse, varistor, etc., are not directly related to the accidents that occurred. The analysis of the characteristics using a switching regulator showed that the charge and discharge characteristics fell short of standard values. In addition, it is thought that heated electrolytic capacitors caused thermal stress to nearby resistances, elements, etc. It can be seen that the heat generation is governed by the over-ripple current, application of AC overvoltage, surge input, internal temperature increase, defective airtightness, etc. Therefore, when designing an electrolytic capacitor, it is necessary to comprehensively consider the correct polarity arrangement, appropriate voltage application, correct connection of equivalent series resistance(ESR) and equivalent series inductance(SEL), rapid charge and discharge control, sufficient margin of dielectric tangent, etc.

• 한국안전학회지
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• 제38권6호
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• pp.9-15
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• 2023

Hydrogen is gaining attention as a sustainable and renewable energy source, potentially replacing fossil fuels. Its high diffusivity, wide flammable range, and low ignition energy make it prone to ignition even with minimal friction, potentially leading to fire and explosion risks. Workplaces manage ignition risks by classifying areas with explosive atmospheres. However, the effective installation of a blast wall can significantly limit the spread of hydrogen, thereby enhancing workplace safety. To optimize the wall installation of this barrier, we employed the response surface methodology (RSM), considering variables such as wall distance, height, and width. We performed 17 simulations using the Box-Behnken design, conducted using FLACS software. This process yielded two objective functions: explosion likelihood near the barrier and explosion overpressure affecting the blast wall. We successfully achieved the optimal solution using multi-objective optimization for these two functions. We validated the optimal solution through verification simulations to ensure reliability, maintaining a margin of error of 5%. We anticipated that this method would efficiently determine the most effective installation of a blast wall while enhancing workplace safety.