• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2007.11a
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• pp.235-237
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• 2007

본 연구는 현장 분진포집에 의한 도전율측정과 전기설비 위험을 평가한 것이다. 현장에서의 분진발생은 전기설비에 악영향을 주어 전기설비의 운영시 발생되는 것과 주변환경적 요인에 의해 발생되는 분진이 주를 이루고 있다. 현장에서 포집된 분진으로부터 분진의 종류, 도전율 특성에 의해 전기설비가 영향을 미칠 것으로 판단되었다. 또한 일부 부식성 가스에 의해 노출된 전기설비의 위험성을 분석하고 관리기준을 마련할 필요가 있는 것으로 나타났다. 분진의 종류에 따라 사고의 과정은 빠르거나 오랫동안 지속되었다가 발생되는 근원적 원인을 규명하고자 국내현장에서 분포되고 있는 분진의 종류와 특성 분석과 관련규정을 검토하고 현장실태에서 나타난 문제점을 검토하여 분진발생지역에서의 전기설비 안전관리를 위한 기준마련에 이용될 것으로 기대된다.

• Analytical Science and Technology
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• v.25 no.3
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• pp.190-196
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• 2012

The human exposure of lead has usually detected the amount of lead in the whole blood, however, this method has a shortcoming to give the information on the short-term exposure to lead. In that sense, it is desirable to estimates the level of lead in plasma to draw the chronic bio-marker of lead exposure even though it is difficult to measure lead of several ng/L. An inductively coupled plasma-mass spectrometry (ICP-MS) method was developed for determining lead in plasma as the chronic bio-marker of lead of workers. To minimize the contamination of lead from the environment, we constructed class 1,000 clean room and compared the amount of floating dust before and after the operation of the clean room. The limit of detection (LOD) and the limit of quantification (LOQ) of lead in fetal bovine serum were 4.3 ng/L and 12.2 ng/L by NIOSH method (statistical calculation method) and 7.0 ng/L and 22.1 ng/L by signal/noise ratio, respectively. The accuracy was in a range of 92.3-101.3%, and the precision of the assay was less than 4% in the samples spiked in the concentration of 20 ng/L and 2,000 ng/L. The method was simple, reproducible and sensitive enough to permit reliable analysis of lead to the ng/L level in plasma and/or serum. The method was also useful for the biological monitoring of chronic exposure to lead.

• Journal of Korean Association for Spatial Structures
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• v.7 no.5
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• pp.75-82
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• 2007

The present work measured and analyzed changes in the acoustics of a sound field which has a retractable ceiling. An 1/20 scale model of an openable space was built and measurement was carried out by varying the opened area of a ceiling. The most widely used room acoustic and design parameters, RT, EDT, and D50 were investigated. The results suggest that the use of RT as an acoustic design parameter may not be proper in an openable space and further it is likely to mislead the initial acoustic design of such spaces. It is mainly due to the characteristics of RT in which non-exponential decay processes are linearly fitted. Early decay times were found to be decreased in proportion to increaing the ratio of opened area. D50, an index of speech intelligibility, was effectively shows the influence of openings on the acoustics. It is also found that EDT and D50 at the seats, not directly exposed to the opened part of a ceiling, were almost linearly decreased in proportion to the ratio of opened area, while little influence was found for the opening ratio larger than 40% at the directly exposed seats to the opened part of a ceiling.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.14 no.6
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• pp.26-34
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• 2000

The considerations for remaining life of ACSR (Aluminum Stranded Conductors Steel Reinforced) in transmission lines have become gradually important to hold reliability and stability of power supply. The remaining life of ACSR exposed to the atmosphere for a long period may rely on deterioration caused by environmental indices such as atmospheric corrosion, galvanic corrosion, crevice corrosion and fatigue corrosion. One of reduction of useful life in overhead transmission lines built on the ridge of mountain is often caused by forest fires.This paper deals with investigation of strength deterioration performance of ASCR due to fires through several testing and analyzing data for tension load and extension of blazed ACSR. Test samples are ACSR 480[$\textrm{mm}^2$] conductors, which are artificially fired to regular durations. Mechanical properties such as tension load and extension for fired ACSR conductors are tested and estimation functions for mechanical performances corresponding to fire duration are determined. As a result, it can be verified that both tension load and extension of ACSR are reduced by increasing fire duration. Hence, it is obvious that ACSR due to forest fires may lead to mechanical deterioration.

• Journal of the Korea Concrete Institute
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• v.23 no.4
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• pp.431-440
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• 2011

Concrete structures exposed to fire produce changes in their internal structure, resulting in their service life reduction due to the deterioration of its strength and performance capacity. The deterioration level are dependent on the temperature, exposure time, concrete mix proportions, aggregate property, and material properties. This study was performed to evaluate the thermal behavior of ultra-high strength concrete for the parameters of water to cement ratio (compressive strength), fine to total aggregate ratio, and maximum coarse aggregate size. At room temperature and $500^{\circ}C$, tests of ultrasonic pulse velocity, resonance frequency, static modulus of elasticity, and compressive strength are performed using ${\varnothing}100{\times}200\;mm$ cylindrical concrete specimens. The results showed that the residual mechanical properties of ultra-high strength concrete heated to $500^{\circ}C$ is influenced by variation of a water to binder ratio, fine to total aggregate ratio, and maximum coarse aggregate size.

• Journal of fish pathology
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• v.15 no.3
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• pp.99-104
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• 2002

Experiments were carried out to investigate the effects of lead exposure on survival, growth and oxygen consumption of juvenile oliver flounder, Paralichthys olivaceus for 6 weeks. Survival rate of the oliver flounder was significantly affected above 150 $\mu{g/L}$. Growth rate of the olive flounder exposed to ≥ 150 $\mu{g/L}$ of lead concentration were significantly decreased than that exposed to normal condition. Metabolic rate in the lead concentration ≥ 80 $\mu{g/L}$ was significantly reduced with increasing lead concentration then that in normal condition. This study revealed that high lead concentration (≥ 80 $\mu{g/L}$) reduced growth and metabolic rate of the juvenile olive flounder suggesting potential influence on the natural mortality of olive flounder in the coastal areas.

• The Korean Journal of Malacology
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• v.27 no.4
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• pp.283-289
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• 2011

This study investigated survival rate, osmorality, respiration, excretion and histological response with change of salinity in the abalone, Haliotis discus hannai at $24{\pm}1^{\circ}C$. Survival rate was 100% at 37.0 psu whereas all died after 6 days at 19.8 psu and within 24 hours at 12.8 psu, respectively. The 7-day median lethal limit (7day-$LS_{50}$) was 20.1-28.2 psu with confidence limits of 20.1-28.2 psu. Respiration rate in low salinity groups was lower than control group, but ammonia excretion rate was more increased in comparison to control group. Osmorality was acclimated within 1 hour at above of 26.8 psu but others could not acclimated at each experimental salinity. Histological observation of foot muscle showed hemolymph sinus distension, epidermal destruction and increased infiltration of phagocytes.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.36 no.1
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• pp.39-43
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• 2003

Experiments were carried out to investigate the effects of long term sub-lethal cadmium exposure on survival, growth and metabolic rate of olive flounder, Paralichthys olivaceus for 6 weeks. Survival rate of the flounder was significantly affected above $980{\mu}g/L$. Growth rates of the flounder exposed to ${\geq}210\;{\mu}g/L$ of cadmium concentration were significantly decreased than that exposed to normal condition, Metabolic rate in the cadmium concentration ${\geq}210\;{\mu}g/L$ was significantly reduced with increasing cadmium concentration than that in normal condition. This study revealed that high cadmium concentration $$({\geq}210\;{\mu}g/L$$ reduced growth and metabolic rate of the juvenile flounder suggesting potential influence on the natural mortality of olive flounder in the coastal areas.

• Proceedings of the Korea Water Resources Association Conference
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• 2019.05a
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• pp.181-181
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• 2019

기후변화의 노출분석에서 가장 중요한 인자는 정확한 강우패턴의 파악이다. 시험지구인 경기도 화성시에 위치한 버들저수지 저수지 상류지역 및 수혜구역을 대상으로 기후변화 유발인자(노출)인 강우량의 변화량을 조사 및 분석 하였다. 시험지구에 대한 강우 변화량 분석은 설계당시의 지배관측소인 수원관측소 자료(1967~2015년)를 이용해 기간이동 변화를 위해 월별, 분기별 강우량를 비교하였다(기준: 1967~2000년 평균). 강우의 공간이용은 수원관측소의 인접 강우 관측소간의 상대적 비교(연강우량 평균)를 통해 강우 변화를 분석하였고, 강우이동은 홍수기 최대강우량 비교하여 분석하였다. 분석결과 5년 단위 평균 강수량은 (기준) 1,292mm 대비 (비교1 : 2001~2005년) 1,292mm, (비교2 : 2006~2010년) 1,408mm, (비교3 : 2011~2015년) 1,349mm로 평균 대비 총강수량은 많아지고 있으며, 5년 단위의 분기별 강우기여율 중 강우의 시간적 이동에 대한 지표인 2분기(4~6월) 기준대비(23%) 비교1(25%) 비교2(21%), 비교3(22%)로 비교1 구간에서만 조금 상승했고 그 후에는 차츰 강우량이 적어진 것으로 분석됐다. 강우가 농업생산기반시설에 미치는 영향 정도를 파악하기 위해 강우량 대비 저수지의 저수율을 비교하였다. 연도별로 만수위가 아닐 때 내린 강우량을 저수지에 유효한 강우량(유효강우량)으로 조건을 주어 분석하였다. 만수위상태에서는 강우가 발생해도 하류하천으로 무효 방류된다. 특히 평수기에는 유효강우량이 30~40% 정도이지만 가뭄시기였던 2014~2016년에는 강우 기여율이 72~86%까지 올라 간 것으로 보아 강우량의 변화에 농업생산기반시설인 저수지가 크게 영향을 미치고 있으므로 "강우량- 저수량"은 농업생산기반시설에 영향을 미치는 인자로 기후변화에 대한 민감도 분석의 영향지표로 이용할 수 있다.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2012.04a
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• pp.290-293
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• 2012

화재는 콘크리트 구조물의 역학적 특성에 치명적 손상을 일으켜 건축물의 안전성을 급격하게 감소시킬 수 있다. 특히 고강도콘크리트는 폭렬이 발생하여 심각한 단면 손실과 노출된 철근으로 인하여 건축물의 안전성에 치명적인 영향을 미친다. 이러한 폭렬에 대하여 다양한 연구가 진행되고 있지만, 폭렬의 발생원인은 명백하게 밝혀지진 않았다. 이에 본 연구는 콘크리트의 함수율과 열응력이 폭렬에 미치는 영향을 분석하여 폭렬로부터 구조물의 안전성을 확보하기 위한 기초 자료를 제시하였다.