• 대한치과보철학회지
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• 제60권3호
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• pp.231-238
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• 2022

목적: 본 연구는 의치상용 레진의 전장방법이 polyetherketoneketone (PEKK)과의 인장결합강도에 미치는 영향을 알아보고자 하였다. 재료 및 방법: 총 80개의 PEKK 시편을 T자 형태로 절삭 가공하고, airborne-particle abrasion 처리 후 전처리제(Visio.link)를 도포하였다. 전장 방법에 따라 4개의 군(n = 20)으로 나누어, 충전형 광중합형 복합레진(SR Adoro), 유동형 광중합형 복합레진(Crea.lign), 열중합형 의치상용 레진(Vertex RS), 자가중합형 의치상용 레진(ProBase Cold)으로 전장하였다. 각 군은 인공시효처리 여부에 따라 2가지 하위 군(n = 10)으로 나누었다. 만능시험기를 이용해 인장결합강도 측정하고 현미경으로 파절단면을 관찰하였다. 통계적 검증을 위해 이원 분산분석 및 Tukey's HSD 사후 검정을 시행하였다(α = .05). 결과: 인공시효처리와 레진 전장방법은 인장결합강도에 통계적으로 유의한 영향을 주었다(P < .001). 인공시효처리 전과 후 모두 유동형 광중합형 복합레진 군에서 가장 높은 값을 보였고, 열중합형 레진 군에서 가장 낮은 값을 보였다(P < .05). 파절 단면은 군에 따라 혼합 파절과 계면 파절이 혼재되어 나타났다. 결론: 레진의 전장 방식은 PEKK과의 인장결합강도에 영향을 줄 수 있으며, 인공시효처리는 인장결합강도를 감소시킨다.

• Journal of Preventive Medicine and Public Health
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• 제33권3호
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• pp.306-312
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• 2000

Background : Polycyclic aromatic hydrocarbons (PAH) are well known environmental pollutants. The measurement of PAH in ambient air is not commonly used, because it is quite difficult to perform and is unreliable. Using biomarkers of PAH can be an alternative approach to this problem. The PAH in ambient air is absorbed in particulate matter. Total suspended particulate(TSP) or particulate matter of less than $10{\mu}m$ in diameter (PM10) can be easily measured. Therefore, TSP or PM10 can be used as a surrogate measurements of ambient air PAH. Objectives : We investigated whether the urinary concentration of two biomarkers of PAH, 1-hydroxypyrene (1-OHP) and 2-naphthol, could reflect the total suspended particulate in the general population. Methods : In order to exclude the effects of occupational exposure and smoking, first grade middle school students were included in this study. Four middle schools within a one kilometer boundary of ambient air monitoring stations were selected. Total suspended particulate was regarded as the marker of airborne PAH. Diet and smoking data were collected by self administered questionnaires, and spot urine samples were collected. Urinary 1-OHP and 2-naphthol were analyzed by high performance liquid chromatography. Results : The correlation between urinary 1-OHP, 2-naphthol and passive smoking was not statistically significant. The correlation between urinary 1-OHP and TSP indices was not statistically significant. The correlations between urinary 2-naphthol and TSP of two lag days, one lag day, and zero lag days were statistically significant. The statistical significance of two lag days was the strongest (p=0.001), one lag day was the next (p=0.0275), and zero lag days was the weakest (p=0.0349). Conclusion : Our results imply that the urinary concentration of 2-naphthol can be applied as a PAH exposure marker for the general population with low PAH exposure.

• 환경영향평가
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• 제25권6호
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• pp.532-541
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• 2016

국가환경시료은행(NESB)에서는 환경오염물질의 생태계 영향을 모니터링하기 위한 시료로서 8종의 생물시료를 정기적으로 채취하여 초저온(<$-130^{\circ}C$) 저장을 해 오고 있다. 이 중 2 종의 활엽수(느티나무 및 신갈나무 잎)가 중금속 및 잔류성유기오염물질(POPs)과 같은 대기오염물질 모니터링을 위한 환경시료로서 활용되기 위해 채취되고 있다. 한 지역을 대표하기 위해 군락 내 여러 개체에서 시료를 채취하는 과정에서 개체별 차이 및 오염분포 특성에 따른 이질성이 구성 시료의 대표성에 영향을 미치게 되고 따라서 분석을 통한 측정값을 활용한 연구의 신뢰도에 문제를 초래할 수 있다. 따라서 이러한 시료종은 엄격한 표준운영절차(SOP)에 따라 채취됨으로써 대표성을 확보할 수 있고 이를 근거로 오염물질의 지역간, 연도별 비교가 가능하게 된다. 본 연구에서는 표준운영절차(SOP)에 따라 5 지역의 고정구에서 채취된 신갈나무, 느티나무 잎 시료를 대상으로 지역 간 오염물질의 농도차이를 비교하기 위해 주요원소 및 중금속, 그리고 다환방향족탄화수소(Polycyclic aromatic hydrocarbons, PAHs)에 대한 분석을 실시하였다. 그 결과인 측정값을 활용하기에 앞서 이에 대한 신뢰도 수준을 평가하기 위한 방편으로 시료채취단계에서 중복 시료를, 시료분석단계에서 중복분석을 수행하여 분산분석(ANOVA)을 수행하였다. 이로써 시료채취 및 분석의 단계별 불확도를 분리하여 산출한 후 측정불확도로 통합한 결과 측정값의 지역 간 연도별 농도비교에 통계적 신뢰도 수준으로 활용할 수 있었다. 아울러 잎표면 대기침적물질 중 강우에 영향을 받는 중금속 및 PAHs 종류를 파악하기 위해 누적강우량과 오염물질의 축적도간 관계를 분석하였다.

• 한국대기환경학회지
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• 제17권5호
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• pp.395-405
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• 2001

To make an assessment of the compatibility between DOAS and conventional point monitoring system (MCSAM-2: MS2), we investigated the concentrations of three criteria pollutants which include S $O_2$, N $O_2$, and $O_3$from a national monitoring station in Seoul during the periods of June 1999~August 2000. The average concentration values for the whole study period derived from hourly concentration data sets of those three species indicated that the mean differences between the two methods can be approximated as 18%. When the bias structure of two systems was evaluated through the computation of percent difference(PD) between the two such as ( $C_{DOAS}$- $C_{conventional}$ $C_{DOAS}$*100, differences between the two systems appeared to be quite systematic among different compounds. While the mode of bias peaked at 0~20% or 20~40% in terms of PD values, the cause of such positive bias mainly arised from generally enhanced concentration values of DOAS system. The structure of bias among different species was further assessed through linear regression analysis. Results of the analysis indicated that the dominant portions of differences observed from two monitoring systems can be accounted for by the systematic differences in their spanning and zeroing systems. S $O_2$(MS2)=0.6385 S $O_2$(DOAS)+2.0985($r^2$=0.7894) N $O_2$(MS2)=0.6548 N $O_2$(DOAS)+7.437($r^2$=0.7687) $O_3$(MS2)=1.0359 $O_3$(DOAS)-7.7885($r^2$=0.7944) The findings of slope values at around 0.64~0.65 from two species suggest that DOAS should respond more sensitively in upper bound concentration range. The offset values apart from zero indicate that more deliberate comparison needs to be made between these monitoring systems. However, based on the existence of strong correlations from at least 8,000 data points for each species of comparison, we were able to conclude that the compatibility of two monitoring systems is highly significant. With the improvement of calibration techniques for the DOAS system. its applicability for routine monitoring of airborne pollutant species is expected to be quite extendable.

• 한국대기환경학회지
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• 제33권6호
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• pp.616-625
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• 2017

Measurements using five real-time particle samplers were compared to measurements using three NRM (National Reference Method system) filter-based samplers(Gravimetric method) at Incheon, Korea, between May and August, 2014. The purpose of this study was to suggest the quality assurance/quality control (QA/QC) method of each instrument for use in a real-time continuous particle sampler to measure the mass of airborne particles with an aerodynamic diameter less than $2.5{\mu}m$ ($PM_{2.5}$). Five real-time particle samplers of BAM1020, FH62C_14, TEOM, PM-711 and SPM-613 were evaluated by comparing its measured 23 hr average $PM_{2.5}$ concentrations with those measured with NRM filter-based samplers simultaneously. The parameters(e.g. Inlet heating condition, Slope factor, Film response, Intercept, Background, Span value) of the real-time samplers were optimized respectively by conducting test performance evaluation during 7 days in field sampling. For example, inlet heating temperature of TEOM sampler controls $35{\sim}40^{\circ}C$ to minimize the fluctuation of the real-time measurement data and background value of BAM1020 is the key factor affecting the accuracy of $PM_{2.5}$ mass concentration. We classified the $PM_{2.5}$ concentration according to relative humidity (80%) to identify water absorbed in aerosols by measuring the ${\beta}$-ray samplers(BAM1020, FH62C_14) and TEOM. ${\beta}$-ray samplers were not strongly affected by relative humidity that the difference of the average $PM_{2.5}$ concentration was about 5%. On the other hand, The TEOM sampler overestimated $PM_{2.5}$ mass concentration about 15% at low relative humidity (<80%).

• 한국대기환경학회지
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• 제34권2호
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• pp.269-280
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• 2018

This paper reports the results of field evaluation to determine the levels of heavy metals in major industrial complexes in Korea over a seven year period (2007~2013). The measurement of heavy metal was conducted using quartz fiber filter sampling and ICP-AES analysis. In order to validate the analytical performance of these methods, studies were also carried out to investigate data quality control(QC) parameters, such as the method detection limit (MDL), repeatability, and recovery efficiencies. The average concentrations of total suspended particulates (TSP) for the nine industrial complexes in Korea were $104{\sim}169{\mu}g/m^3$, which was higher than other industrial complexes and urban areas. The Sihwa and Banwol industrial complexes were shown to be the biggest contributing sources to high TSP emission ($159{\mu}g/m^3$ and $169{\mu}g/m^3$, respectively). The concentrations of heavy metals in TSP were higher in the order of Fe>Cu>Zn, Pb, Mn>Cr, Ni, As and Cd. It was observed that Fe was the highest in the Gwangyang and Pohang steel industrial complexes. The concentrations of Zn and Pb were high in Onsan, Sihwa and Banwol industrial complexes, and this was attributed to the emission from the nonferrous industry. Additionally, Cr and Ni concentrations were high in the Sihwa and Banwol industrial complexes due to plating industry. On the other hand, Ulsan and Onsan industrial complexes showed high Cr and Ni concentrations as a response to the emission of metal industry related to automobile. The correlation analysis revealed the high correlation between Cr and Ni in plating industry from Sihwa and Banwol industrial complexes. Adding to this, components related to coal combustion and road dust showed high correlation in Pohang and Gwangyang industrial complexes. Then Onsan and Ulsan industrial complexes showed high correlation among components related to the nonferrous metals.

• Safety and Health at Work
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• 제6권3호
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• pp.174-183
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• 2015

The major purpose of this study is to construct a retrospective exposure assessment for benzene through a review of literature on Korea. Airborne benzene measurements reported in 34 articles were reviewed. A total of 15,729 individual measurements were compiled. Weighted arithmetic means [AM(w)] and their variance calculated across studies were summarized according to 5-year period intervals (prior to the 1970s through the 2010s) and industry type. Industries were classified according to Korea Standard Industrial Classification (KSIC) using information provided in the literature. We estimated quantitative retrospective exposure to benzene for each cell in the matrix through a combination of time and KSIC. Analysis of the AM(w) indicated reductions in exposure levels over time, regardless of industry, with mean levels prior to the 1980-1984 period of 50.4 ppm (n = 2,289), which dropped to 2.8 ppm (n = 305) in the 1990-1994 period, and to 0.1 ppm (n = 294) in the 1995-1999 period. There has been no improvement since the 2000s, when the AM(w) of 4.3 ppm (n = 6,211) for the 2005-2009 period and 4.5 ppm (n = 3,358) for the 2010-2013 period were estimated. A comparison by industry found no consistent patterns in the measurement results. Our estimated benzene measurements can be used to determine not only the possibility of retrospective exposure to benzene, but also to estimate the level of quantitative or semiquantitative retrospective exposure to benzene.

• 한국환경보건학회지
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• 제37권1호
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• pp.29-43
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• 2011

The seasonal characteristics of atmospheric particulate matter (PM) were evaluated through the measurement of $PM_{10}$ (particles with an aerodynamic diameter of less than 10 ${\mu}m$) and $PM_{2.5}$ (particles with an aerodynamic diameter of less than 2.5 ${\mu}m$) collected in the downtown area of Iksan city over roughly two weeks in each season of 2004. During the sampling period, 54 samples of $PM_{10}$ and $PM_{2.5}$ were collected and then measured for mass concentrations of PM and its water-soluble inorganic ion species. The concentrations of $PM_{10}$ and $PM_{2.5}$ were highly variable on a daily time scale in all seasons, especially in fall. Annual concentrations of $PM_{10}$ and $PM_{2.5}$ were $54.7{\pm}21.6\;{\mu}g/m^3$ and $34.0{\pm}13.4\;{\mu}g/m^3$, respectively. The daily concentrations of the analyzed ions similarly showed a pronounced variation, although a difference between seasons existed. Among them, $SO_4^{2-}$, $NO_3^-$ and $NH_4^+$ were the most abundant ions in all seasons, contributing up to 32% of $PM_{10}$ and 39% of $PM_{2.5}$. The contribution of $SO_4^{2-}$ and $NO_3^-$ showed a seasonal variation, as $SO_4^{2-}$ was the highest during spring and summer and $NO_3^-$ was the highest during fall and winter. Non-seasalt $SO_4^{2-}$ and $NO_3^-$ were found to exist mainly as neutralized chemical components of $(NH_4)_2SO_4$ and $NH_4NO_3$ due to the high concentration of $NH_4^+$ in PM samples, which were a major form of airborne PM in all seasons. Seasonal characteristics of $PM_{10}$ and $PM_{2.5}$ in Iksan were described in relation to the temporal variations of daily concentration of PM and its inorganic ion species including inter-particle reactions.

• 대한공간정보학회지
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• 제23권2호
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• pp.39-48
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• 2015

최근, 무인항공촬영시스템(UAV, UAS, 또는 드론)은 자료취득을 위한 플랫폼 및 측정기기로서 사진측량의 응용분야, 특히 고밀도 측점자료(HDPC : High Density Point Clouds) 구성에 큰 관심이 모아지고 있다. 본 연구는 저가회전익 UAS 영상에 의한 시험대상지 지표면의 고밀도 측점자료를 구성하고 위치 정확도를 평가한 내용이다. 정확도 평가는 62개의 지상 검사점에 대한 Network RTK GNSS 측량 결과를 기준으로 UAS 기반 HDPC 모형의 좌표와 비교 검토하였다. 연구결과, 작업지역 정사영상 내, 검사점의 평면 및 수직 좌표성분의 평균제곱근오차(RMSE)는 각각 ${\sigma}_H={\pm}0.102m$ 및 ${\sigma}_V={\pm}0.209m$, 수직 좌표성분의 최대오차는 0.570m로서 '영상지도제작 작업규정'에 따른 축척 1:1000(출력 시, 평면위치오차 1m)의 정사영상모자익 제작이 가능하였다. 또한, 격자규격 $1m{\times}1m$, 수치지도축척 1:1000의 수치표고모델을 제작할 경우, '항공레이저측량 작업규정'제한 기준에는 약간 미흡하였지만, 소규모지역을 대상으로 회전익 무인항공촬영시스템에 의한 축척 1:1000~1:2500의 정사영상 및 수치표고모델 제작의 가능성을 확인할 수 있었다.

• Journal of Radiation Protection and Research
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• 제34권4호
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• pp.184-189
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• 2009

중수로원전의 방사선작업종사자는 방사선작업 종료 후에 뇨시료를 제출하여 공기중 삼중수소의 섭취에 따른 내부피폭 선량을 평가하고 있다. 이 경우 종사자가 제출한 뇨시료는 삼중수소가 체내에서 평형에 도달한 대표시료(Representative sample)라는 전제를 필요로 한다. 국제방사선방호위원회(ICRP)의 간행물과 삼중수소의 인체평형에 대한 캐나다의 실험결과에 의하면 체내로 유입된 삼중수소는 약 2-3시간 후에 평형에 도달한다고 기술하고 있다. 그런데 원전에서는 계획예방정비기간 동안 일시에 많은 작업이 진행되고 빈번한 종사자의 출입으로, 방사선작업 종료 후 제출하는 뇨시료는 섭취 후 평형에 도달하는 약 2시간 경과 이전에 제출하거나, 지연하여 제출하는 경우가 발생할 수 있다. 따라서 이 논문에서는 방사선작업 종료 후 종사자가 제출하는 시간대별 뇨시료 중의 삼중수소 농도를 측정하였고, 이를 근거로 체내 삼중수소의 농도에 대한 변화추이와 선량평가에 미치는 영향을 분석하였다. 그 결과 종사자의 뇨시료는 대부분 삼중수소 섭취 후 2시간 정도에 신체 내에서 평형에 도달하는 것으로 확인되었다.