• 국제학술발표논문집
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• The 1th International Conference on Construction Engineering and Project Management
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• pp.459-468
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• 2005

International contractors must consider the substantial risks related to unexpected foreign exchange fluctuation incurred by conducting their business and using foreign currencies in foreign countries. Most international contractors attempt to minimize foreign exchange exposure within a manageable range because it may influence the company's fundamental financial structure, reduce market value or profit margins, or disrupt ongoing and future projects. This research provides a qualitative study of existing foreign exchange exposure (transaction, operation, and translation exposure) and current & effective foreign exchange risk management in American and Korean international contractors, as they represent both new and long-time members of the global construction market. Finally, recommendations of techniques for new and existing international contractors to minimize and better manage foreign exchange risk will be offered.

• 한국구조물진단유지관리공학회 논문집
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• 제25권1호
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• pp.67-74
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• 2021

본 논문에서는 노후화된 PSC I형 교량을 대상으로 철근부식에 대한 구조적 안전성을 평가하였다. 대상 PSC I형 교량은 실제 구조물을 참고하여 철근을 배근하고 해석 시 콘크리트의 파괴와 철근의 항복을 고려하였다. 한국시설안전공단 정밀안전진단의 교량 평가 기준을 참고하여 철근노출면적률과 철근부식률로 구분하여 총 32가지의 철근부식 시나리오를 구성하였다. 철근노출은 교량의 바닥판 하부 인장철근이 콘크리트 피복 탈락에 의해 노출된 것으로 가정하였다. 각 시나리오별 해석 결과, PSC I형 교량의 안전율과 내하율은 철근노출면적률과 철근부식률이 증가함에 따라 감소하였다. 철근부식률이 50% 이상일 경우는 모든 철근노출면적률에 대해서 안전성등급을 세밀하게 분석할 필요가 있었으며, 철근부식률 57%이상인 경우는 철근노출면적률에 관계없이 모두 E등급으로 산정되었다. 철근노출면적률 2%에 대해서 상관도 분석을 실시한 결과,철근부식률이 약 55.8% 까지는 A등급, 56.9% 까지는 C등급, 58.5% 까지는 D등급, 58.5% 이상인 경우 E등급으로 평가되었다. 본 연구를 통해 노후화된 교량에 대한 철근부식의 정량적인 구조적 안전성 평가가 필요할 것으로 판단된다.

• 한국산업보건학회지
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• 제5권1호
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• pp.48-58
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• 1995

This study was performed to find out the exposure level of mixed organic solvents, excretion of urinary hippuricacid and subjective symptoms according to the exposure of organic solvents of female workers who works on 5 shoes manufacturing industries in Taejon City from 24, september to 20, october 1993. The studied groups were divided into 3 groups that were consist of direct exposure group(48 workers), indirect exposure group(49 workers) and non-exposure group(68 workers) to the organic solvents. The exposure levels of toluene of direct exposure group which $89.86{\pm}56.20ppm$ had higher than that of indirect exposure group which had $40.23{\pm}47.21ppm$. In the exposure level of mixed organic solvent(R-value), direct exposure group was $2.84{\pm}1.53$ and exceeded approximatly 3 times the R-value. Whereas, indirect exposure group was not exceeded the R-value as $0.80{\pm}0.61$. In the excretion level of urinary hippuric acid, direct exposure group was $1.78{\pm}1.25g/l$, indirect exposure group was $1.22{\pm}0.93g/l$ and non-exposure group was $0.51{\pm}0.18g/l$ respectively. Therefore both direct exposure group and indirect exposure group were significantly higher than non-exposure group(P<0.01). In the correlation between toluene levels and urinary hippuric acid level, the direct exposure group had positive correlation(R=0.8309, P<0.01), also indirect exposure group had positive correlation(R=0.5859, P<0.05) and also in the correlation between the R value of mixed organic solvents and the urinary hippuric acid levels, the direct exposure group had positive correlation(R=0.4492, P<0.05), and indirect exposure group had ositive correlation(R=0.7911, P<0.01). In the complain rates of the worker's subjective symptoms at work, both direct exposure group and indirect exposure group were higher than non-exposure group(P<0.05, P<0.01). But the sujective symptoms of "floating sensation" of direct exposure group had significantly higher than indirect exposure group. In the percent of subjective symptoms complaints during the worker's daily life, both direct exposure group and indirect exposure group had generally more statistical significance than nonexposure group(P<0.01), direct exposure group had not statistical significant difference from indirect exposure group. As the results mentioned above, it has been analysed that the indirect at the adjacent manufaturing process are exposed to the considerable amount of solvent. Therefore, I think that there should be the betterment of surrounding through the complete working environment management to the occurrence source of the organic solvent, the changes of health management system to the indirect-exposed workers, and the systematic management of the special medical examination and the like.

• Asian-Australasian Journal of Animal Sciences
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• 제22권3호
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• pp.328-335
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• 2009

This study was undertaken to investigate the influence of exposure and removal of four different cryoprotectants (CPAs) on the ATP content of cumulus cell-enclosed (COs) and cumulus cell-denuded (DOs) immature porcine oocytes. The in vitro nuclear maturation of the COs, exposed to and removed from the CPAs was also assessed. Both COs and DOs were exposed to 1.5 M concentrations of each CPA (ethylene glycol (EG); propylene glycol (PG); dimethyl-sulfoxide (DMSO); and glycerol (G)) for durations of 5, 15, and 30 minutes at room temperature ($23.5{\pm}1.5^{\circ}C$), and immersed in physiological saline supplemented with 20% (v/v) fetal bovine serum for 5 minutes ($39^{\circ}C$) to remove each CPA. Before, during and after exposure to each CPA, the ATP content of both the COs and the DOs was measured. After removal from each CPA an aliquot of the COs was matured for 44${\pm}$2 h, and their nuclear maturation rates were measured up to the metaphase stage of the second meiotic division (the M-II stage). The maturation rates up to the M-II stage were not significantly different between all the groups that were exposed to each CPA for 5 minutes. For 15 and 30 minute exposures, the maturation rates of the COs exposed to PG, DMSO and EG were almost the same as those of the control groups; however, the rates of G group exposed for 15 and 30 minutes were significantly lower (p<0.05) than the control group. These groups were also found to have a decrease in the ATP content of COs and DOs during and after exposure for the same periods (p<0.05). In addition, although the ATP contents of the COs after exposure to EG for any period were the same as the controls, the ATP content of the DOs exposed to EG for any period were significantly lower (p<0.05) than those of the controls. When the ATP content of the COs and DOs of each CPA were compared, the DOs exposed to PG were found to have a significantly greater level (p<0.05) than DOs exposed to G for any duration. In addition, the ATP content of DOs exposed to PG for 30 min and removal was also higher (p<0.05) than when exposed to DMSO for the same period. These findings indicate that PG may be a useful CPA for the cryopreservation of immature porcine oocytes.

• 한국수산과학회지
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• 제36권1호
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• pp.44-48
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• 2003

넙치 (P. olivaceus)를 카드뮴 아치사 농도인 5, 50, 100 ${\mu}g/L$의 구간에 30일간 노출시킨후 청장기간을 가져 아가미, 간, 신장, 창자 및 근육에서 축적된 카드뮴의 제거정도를 조사하였다. 아가미에서는 노출농도 50 ${\mu}g/L$ 이상에서는 배출 10일째부터 유의한 감소를 나타내었으며, 배출이 가장 빨랐던 기관은 창자로써 배출 10일째부터 노출농도 50, 100 ${\mu}g/L$에서 $50\%$ 이상의 제거율을 나타냈다. 간은 배출 10일째부터 유의한 감소를 나타냈으며, 노출 20일 이후에는 노출구간 50, 100 ${\mu}g/L$에서는 각각 $66.20\%$와 $86.22\%$의 제거율을 나타냈다. 신장에는 카드뮴 노출이후 각 구간에서 유의한 감소를 나타내지 않았으며, 근육은 다른 기관들과는 달리 카드뮴 노출 이후 배출실험에서도 지속적인 농도 증가가 나타냈다. 카드뮴 노출 30일 후 배출되는 20일 동안 가장 많이 배출되는 기관의 순서는 창자>간${\geq}$아가미>>신장의 순으로 나타났다. 아가미, 창자와 간은 배출 20일 동안 급격한 카드뮴의 제거가 나타났으며, 신장은 유의적인 배출이 이루어지지 않고 농도변화가 거의 없었다. 근육은 배출이 이루어지지 않고, 카드뮴이 없는 해수에서도 지속적으로 증가하는 경향을 나타내었다.

• Corrosion Science and Technology
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• 제2권4호
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• pp.183-188
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• 2003

Corrosion of carbon and weathering steels were evaluated under 3 environmental exposures in Thailand (urban, rural and marine) for a year. The seasonal study was designed to determine different corrosion mechanisms by 6 months of dry season and 6 months of rainy season in a year. The sheltered exposure racks were used to determine the washing effect of min. At each site, climatic and pollutants analyses were carried out. The present study showed that the difference in corrosion rates of carbon and weathering steels was not so distinguished in both rural (AIT) and urban (TISTR) environments. The corrosion rate of weathering steel was somewhat lower than that of carbon steel and the decreasing tendency of corrosion rate with time was slightly higher for weathering steel than for carbon steel. In marine (Rayong) environment, the corrosion rate was higher and the effect of wet and dry seasons was observed. The corrosion rate in 6 dry months was higher for direct exposure than for sheltered exposure. However, in 6 rainy months. the corrosion rate of sheltered exposure was higher than that of direct exposure. In direct exposure for I year, that is, the first 6 dry months and the next 6 rainy months, the corrosion rate decreased with time. but in sheltered exposure, the corrosion rate did not decrease with time. instead, increased in the next 6 rainy months. This indicated that the protect ive layer formed in the first 6 dry months could be destroyed by high deposition of chloride to r sheltered exposure in the next 6 rainy months; whereas the rust layer for direct exposure could be kept sound due to washing effect in rainy season, even though the deposition rate of chloride was almost the same for direct and sheltered exposures. In marine environment, the weathering steel showed higher corrosion resistance than carbon steel but its corrosion rate was higher than those in other environments.

• 미생물학회지
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• 제49권1호
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• pp.51-57
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• 2013

대학 구내 학습시설과 집기들은 다중에 의해 이용되기 때문에 그 표면들은 감염성 병원체의 교차감염의 경로로 작용할 수 있다. 그러나 구내 집단급식소 등의 주요 위생관리 시설과 달리 정기적 위생관리의 대상이 아니며, 위생상태 현황이 잘 파악되지 않고 있다. 본 연구는 한 대학 단과대학 1,500여 명의 학생들이 강의실, 도서관 등 학습시설을 이용하면서 병원체에 노출될 수 있는 미생물학적 위해도를 구내급식소에서 집기 접촉을 통해 위해도와 정량적으로 비교하였다. 총대장균군을 병원성의 미생물의 대리모델로 간주하고, 학생들이 공통적으로 이용하는 대학구내 집기별로, 표면의 세균농도에 접촉률, 전이율 등을 적용한 노출알고리즘을 설정하여 결정론적 방법에 의한 노출량을 산정하였다. 급식소 집기의 세균에 대한 노출량은 약 1.0 CFU/day이었으며, 학습시설의 세균에 대한 노출량은 0.5 CFU/day로 급식소에서 노출량의 절반에 해당하였다. 그러나, 개인별 급식소 이용 정도가 달라, 약 70%의 학생들은 급식시설보다 학습시설의 인체접촉면에서 교차감염에 더 많이 노출되는 것으로 나타났다. 결론적으로, 승강기버턴을 비롯한 일부 학습 시설의 인체접촉면은 급식소와 마찬가지로 주기적 위생관리를 필요로 하는 것으로 판단되며, 학생들의 개인위생 관리 이외에, 계절적으로 변동하는 교차감염 가능 병원체의 종류에 부합하도록 인체접촉면 위생관리를 효율적으로 실시하는 것이 권고된다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 하계학술대회 논문집 Vol.5 No.1
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• pp.284-287
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• 2004

Micro-structures fabricated by X-ray lithography are largely affected by doses, development conditions and other factors. For these reasons, PMMA development rates and its surface profiles under various development conditions were obseued. Development rates were measured in the rage from 1 to 6 $kJ/cm^3$ using the 9C1 white beamline of Pohang light source(PLS). In this experiment, we observed that development rates of stacked PMMA sheet using Si filter were relatively higher than that of not using Si filter. Furthermore, development rates in condition with the acoustic agitation(1 MHz, 3.67 $W/cm^3$) were twice than that in dipping condition with $35^{\circ}C$ developer considering the PMMA sheets-substrate bond strength

• 한국환경보건학회지
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• 제24권2호
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• pp.80-87
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• 1998

To evaluate the effects on health by exposure to low dose organic solvents, the author analyzed the air concentration of mixed organic solvents (toluene, xylene, butylacetate) at worker's breathing zone during painting, some laboratory findings of blood (WBC, RBC, Hb, Hct, SGOT, SGPT, TC, TG, HDL-C, LDL-C, IgG, IgM, IgA and IgE) and urine (hippuric acid, urinary protein, urobilinogen), surveyed the subjective symptoms those were obtained from 35 male workers exposed to mixed organic solvents, and 25 male workers not exposed to organic solvents who worked in car repair workshops in Taejon area from December 1, 1995, to February 29, 1996. The results were as follows: 1. The mean concentration of urinary hippuric acid of car painting worker group (organic solvent exposure group) was 0.76$\pm$ 0.21 g/l, which is significantly higher than that of non-exposed group. 2. In hematologic findings, the values of RBC, TC, LDL-C, IgG and IgE in the exposure group were significantly lower than those of the nonexposed group, but SGOT and SGPT in the exposure group were significantly higher than those of the non-exposed group. 3. Urinary hippuric acid levels showed positively correlated with toluene, urobilinogen and HDL-C levels, but those were negatively correlated with RBC, LDL-C, IgM levels. 4. Rates of the subjective symptoms such as "dizziness", "appetite loss", "weight loss", "palpitation", "chest tightness", "sore throat and eye discomfort", "tingling sense and acrodynia", "illusion or hallucination" and "decreaased motor power" were significantly higher in the exposure group than those of the non-exposed group.

• Journal of Radiation Protection and Research
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• 제38권3호
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• pp.157-165
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• 2013

To determine the factors affecting the external radiation dose rates of patients undergoing PET-MRI examinations and to assess the trends of these differences, we measured the changes in the dose rates of $^{18}F$-FDG during a set period of time for each body region. Consistent with theoretical predictions, the dose rate decreased over time in patients undergoing PET-MRI examinations. Furthermore, immediately after the $^{18}F$-FDG injection, the dose rate in the chest region was the highest, followed by the abdominal region, the head region, and the foot region. The dose rate decreased drastically as time passed, by 2.47-fold, from $339.23{\pm}74.70mSv\;h^{-1}$ ($6.73{\pm}5.79$ min) at the time point immediately after the $^{18}F$-FDG injection to $102.71{\pm}26.17mSv\;h^{-1}$ ($136.11{\pm}25.64$ min) after the examination. In the foot region, there were no significant changes over time, from $32.05{\pm}20.23mSv\;h^{-1}$ ($6.73{\pm}5.79$ min) at the time point immediately after the $^{18}F$-FDG injection, to $23.89{\pm}9.14mSv\;h^{-1}$ ($136.11{\pm}25.64$ min) after the examination. The dose rate is dependent on the individual characteristics of the patient, and differed depending on the body region and time point. However, the dose rates were higher in patients who had a lower body weight, shorter stature, fewer urinations, lower fluid intake, and history of diabetes mellitus. To decrease radiation exposure, it is difficult or impossible to change factors inherent to the patient, such as sex, age, height, body weight, obesity, and history of diabetes mellitus. However, factors which can be changed, such as the $^{18}F$-FDG dose, fasting time, fluid intake, number of urinations, and contrast agent dose can be controlled to minimize the external radiation exposure of the patient.