• 식물병연구
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• 제13권2호
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• pp.98-103
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• 2007

포도나무의 추위피해는 여러 형태로 나타난다. 월동피해 중에는 기계적 피해, 동해 또는 수세의 약화 원인이 된다. 본 연구는 '거봉'의 뿌리혹병의 피해를 억제하기 위하여 저항성 대목의 선발과 월동법 개선을 통한 방제법을 개발하기 위하여 실시하였다. SO4, 5BB, 3306대목에 $10^4cfu/ml$의 뿌리혹병균(YK2823, YK3312, LMG259, HKA234)을 접종했을 때는 혹이 발병하지 않았으나 $10^6cfu/ml$의 높은 농도에서는 모든 대목에서 혹이 형성된다. 그러나 혹의 크기는 거봉에서보다 매우 작았다. 인공접종에 의하여 3품종의 뿌리혹병 저항성 대목을 선발하였다. 볏짚과 보온덮개로 줄기와 가지에 피복하는 월동법은 뿌리 혹병을 예방하는데 가장 효과적이었다. 이러한 처리방법은 포도나무가 월동하는 동안 수체의 온도 차이가 $9.6^{\circ}C$로 온도변화가 최소화되었고 동해발생이 없어 정상적으로 생육하였다.

• Journal of the Korean Wood Science and Technology
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• 제35권6호
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• pp.65-72
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• 2007

VOC Analyzer는 공기 중에 포함되어 있는 VOC (휘발성 유기화합물) 중 toluene, ethyl benzene, xylene, styrene 등 4가지 방향족 탄화수소 가스 농도를 측정하는 측정 장비이다. 검출기에는 고감도 반도체 가스센서를 사용한 가스크로마토그래피방식으로써 캐리어 가스로서는 봄베공기를 사용한다. 또한, 대기 중에 포함되어 있는 다양한 가스성분을 농축하지 않고 VOC를 분리 검출하여 농도를 편리하면서도 자세하게 측정할 수 있으므로 건축자재, 페이트, 도료, 접착제 등에서 응용될 수 있다. 이러한 장점을 가진 VOC Analyzer를 이용하여 목재에 주로 사용되는 도료로부터 VOC 방사거동을 확인하였다. 실험은 시편을 밀봉하여 실험개시 후 일정시간 간격으로 48시간까지 측정하였다. 수용성 페인트와 enamel 페인트의 VOC 방산량은 lacquer와 urethane vanish에 비해 상대적으로 적었으며 4개의 샘플 중에서 lacquer의 VOC 방산량이 가장 높게 나타났다. VOC Analyzer를 이용한 측정법은 현재 사용되고 있는 VOC 측정방법 중 가장 빠르고 경제적인 기술이기 때문에 앞으로 널리 사용된 것이라 기대된다.

• 한국해안해양공학회지
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• 제17권4호
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• pp.259-268
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• 2005

여름에 기본적으로 방조제 내부로부터 담수의 유입으로 발생된 저 간소 수괴가 저서생물의 감소를 야기시키기 때문에 영산강 하구언에서 저 산소층의 제거에 대한 관심이 증폭되어왔다. 처리된 하$\cdot$ 폐수를 해양에 방류하는 해양방류시스템이 이러한 저 산소층을 제거하는 효율적이고 경제적인 방법으로 이용되어 질 수 있다. 본 연구에서는 근역에서 방류된 부력제트의 거동을 예측하고자 적절한 방류구의 설계가 제안되었다. 신뢰할 수 있는 부력제트의 거동에 대한 계산을 수행하기 위하여 측정된 CTD와 해류 자료 등을 포함한 인자들이 고려되어졌다. 조석의 주기에 따라 계산된 부력제트의 경계 내에 염분도와 용존산소의 횡분포의 변화를 예측하고자 여러 수치 모형중의 하나로 EPA에 의해 승인된 CORMIX 1 모형을 사용하였다. 수치실험의 결과를 기준으로 볼 때 단공방류구가 저 산소층을 제거하는데 유용한 시스템임을 알 수 있었다. 원활한 주변수의 조건을 만족시키기 위하여 적절한 전략이 또한 제안되어졌다.

• 한국식품영양학회지
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• 제25권2호
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• pp.393-397
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• 2012

본 연구에서는 온도 변화 방법을 이용하여 조미계란을 신속하게 제조하기 위한 가염방법을 개발하고자 하였다. 먼저 염지액의 농도에 따른 계란 내부로 염분의 침투 효과를 분석한 결과, 20, 30 및 40%의 염지액에서 2시간 동안 염지시킨 각각의 계란내 염분 함량은 0.51, 0.57 및 0.60%를 나타내어 농도가 높아질수록 침투효과가 향상되는 것을 확인할 수 있었으며, 고온에서 저온으로 계란의 온도 변화를 유도한 온도변화 방법을 적용한 경우 2시간 동안 계란내 염분 함량이 각각 0.49, 0.56 및 0.70%를 나타내어 40%의 염지액에서 염분의 침투 효과가 향상되었다. 그리고 4, 5 및 7 MPa의 압력을 가하여 40%의 염지액으로 15분간 염지한 경우, 각각 1.14, 1.36 및 1.45%의 염분 함량을 나타내어 대기압 조건에서 침투시킨 결과보다 빠르게 침투되었다. 온도 변화 방법을 적용하여 4, 5 및 7 MPa의 압력을 가하여 40%의 염지액으로 15분간 염지한 경우 각각 1.52, 1.62 및 1.66%의 염분 함량을 나타내어 온도 변화 방법에 의해 침투 효과가 향상됨을 확인할 수 있었다. 이는 계란의 온도 변화 방법이 계란 내부 난막의 수축효과로 외부 염분의 흡입을 유도하였기 때문으로 생각되며, 조미계란을 신속하게 제조하기 위한 가염 방법으로 온도 변화 방법의 적용이 매우 효과적이라고 생각된다.

• 한국환경과학회지
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• 제25권10호
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• pp.1349-1368
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• 2016

Concentrations of fine particulate matter ($PM_{2.5}$) and several of its particle constituents measured outside homes in Houston, Texas, and Los Angeles, California, were characterized using multiple regression analysis with proximity to point and mobile sources and meteorological factors as the independent variables. $PM_{2.5}$ mass and the concentrations of organic carbon (OC), elemental carbon (EC), benzo-[a]-pyrene (BaP), perylene (Per), benzo-[g,h,i]-perylene (BghiP), and coronene (Cor) were examined. Negative associations of wind speed with concentrations demonstrated the effect of dilution by high wind speed. Atmospheric stability increase was associated with concentration increase. Petrochemical source proximity was included in the EC model in Houston. Area source proximity was not selected for any of the $PM_{2.5}$ constituents' regression models. When the median values of the meteorological factors were used and the proximity to sources varied, the air concentrations calculated using the models for the eleven $PM_{2.5}$ constituents outside the homes closest to influential highways were 1.5-15.8 fold higher than those outside homes furthest from the highway emission sources. When the median distance to the sources was used in the models, the concentrations of the $PM_{2.5}$ constituents varied 2 to 82 fold, as the meteorological conditions varied over the observed range. We found different relationships between the two urban areas, illustrating the unique nature of urban sources and suggesting that localized sources need to be evaluated carefully to understand their potential contributions to $PM_{2.5}$ mass and its particle constituents concentrations near residences, which influence baseline indoor air concentrations and personal exposures. The results of this study could assist in the appropriate design of monitoring networks for community-level sampling and help improve the accuracy of exposure models linking emission sources with estimated pollutant concentrations at the residential level.

• 한국입자에어로졸학회지
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• 제16권1호
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• pp.19-30
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• 2020

The organic carbon in the ambient particulate matter (PM) is divided into primary organic carbon (POC) and secondary organic carbon (SOC) by their formation way. To regulate PM effectively, the estimation of the amount of POC and SOC separately is one of important consideration. Since SOC cannot be measured directly, previous studies have evaluated determination of SOC by the EC tracer method. The EC tracer method is a method of estimating the SOC value from calculating the POC by determining (OC/EC)pri which is the ratio of the measured values of OC and EC from the primary combustion source. In this study, three different ways were applied to OC and EC concentrations in PM_2.5 measured at Seoul for determining (OC/EC)pri: 1) the minimum value of OC/EC ratio during the measurement period; 2) regression analysis of OC vs. EC to select the lower 5-20% OC/EC ratio; 3) determining the OC/EC ratio which has lowest correlation coefficient value (R²) between EC and SOC which is reported as minimum R squared method (MRS). Each (OC/EC)pri ratio of three ways are 0.35, 1.22, and 1.77, respectively from the 1 hourly data. We compared the (OC/EC)pri ratio from 1hourly data with 24 hourly data and revealed that (OC/EC)pri estimated from 24 hourly data had twice larger than 1hourly data due to the low time resolution of sampling. We finally confirmed that the most appropriate value of (OC/EC)pri is that calculated by a regression analysis of 1 hourly data and estimated SOC amounts at PM_2.5 of the Seoul atmosphere.

• 대한기관식도과학회지
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• 제6권1호
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• pp.29-37
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• 2000

Background and Objectives : The concentration of sulfur dioxide($SO_2$) gas in the ambient air appears increasing in the industry and urban area day by day. It was known that $SO_2$ is noxious gas. $SO_2$ can be irritating to the eyes, nose, throat, upper respiratory tract and skin. It produces sulfurous acid on contact with water and is extremely irritating to the nasopharynx and respiratory tract. Laminin is a family of extracellular matrix glycoproteins localized in the basement membrane that separates epithelial cells from the underlying stroma. The biological activities of laminin are to promote cell migration, wound healing, growth and differentiation. Meterials and Methods : The histologic changes and the expression of laminin in tracheal mucosa sacrificed at every weeks (to 7 weeks) after continued $SO_2$ exposure of 250ppm for 30 minutes a day were studied in rats. Results : Pathologic tissue was formed at the tracheal mucosa and the underlying tissue by the infiltration of monocytes and epithelium was transformed to the single cell layered epithelium above 5 weeks after exposure. At the 6 weeks after exposure, epithelial cells were partially lost and epithelial cell layer was transformed to be leaf-shaped. Submucosal tissue was transformed to be lymphatic tissue. An intense positive staining for laminin was found in apical cytoplasm and lateral surface of the normal epithelial cells and basement membrane but at the 5 and 6 weeks after exposure, laminin activity was decreased to the moderate activity. At the 7 weeks after exposure, laminin activity was decreased to the weak activity. Conclusion : Our finding suggests that $SO_2$ makes histologic damage on the tracheal mucosa and decreases immunoreactivity for laminin. Longer duration of the exposure of $SO_2$ makes more histologic damage on the tracheal mucosa and decreases immunoreactivity for laminin.

• 한국대기환경학회지
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• 제24권1호
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• pp.72-82
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• 2008

Benzene is a very harmful and toxic compound known as human carcinogen by all routes of exposure. Owing to the risky feature of benzene, several countries such as Japan, UK and EU have established the ambient air quality standard and protect from that risk of it. Korea also has designated it as one of the criteria air pollutants and established the concentration limit ($5\;{\mu}g/m^3$) in the air and is going to apply the standard from 2010. Benzene is emitted from various sources such as combustion plants, production processes, waste treatment facilities and also automobiles. Mobile source is known as one of the major emission sources of benzene. In this study, we estimated the domestic emissions of benzene from mobile source and compared the results with those of advanced countries. Mobile source was divided into 2 categories, Le., on-road source and non-road source. The total emissions of benzene from mobile source were estimated as 3,106 tons/yr and 1,612 tons/yr was emitted from on-road source and 1,494 tons/yr was from non-road source. Emission ratio of benzene from on-road source showed that 80.0% was from passenger cars, 10.1% was from taxis, 7.2% was from light-duty vehicles, 2.5% was from heavy-duty vehicles and 0.2% was from buses. In the case of non-road source, the distribution showed that 66.3% was from construction machineries, 14.5% was from locomotives, 11.7% was from ships, 7.1% was from agriculture equipments and 0.5% was from aircrafts. The cold-start emissions were estimated as 942 tons/yr and this value was almost 1.5 times greater than that for hot engine emissions (608 tons/yr). In addition, the fuel-based distribution was 65.9%, 31.1% and 2.8% from gasoline, LPG and diesel vehicles, respectively. The emission ratio from mobile source occupied 65% and 30% of total benzene emissions in USA and UK, respectively. In case of Korea, the emission ratio of benzene from mobile source occupied 29% (15% from on-road source, 14% from non-road source) which showed similar value with UK.

• 대한환경공학회지
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• 제22권1호
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• pp.21-31
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• 2000

본 연구에서는 공기청정기, 기수분리기 및 중성능 필터로 구성되는 습식 공기청정장치를 대상으로 입자와 유해가스인 $SO_2$, NO, $NO_2$, HCHO 및 $NH_3$의 제거 특성을 실험적으로 살펴보고, 실험결과를 대상물질의 물리화학적 특성과 연관시켜 검토하였다. 입자제거 실험에서는 대기 에어로졸을 송풍기를 통해 장치에 도입하여 장치의 3곳에서 2대의 레이저 입자계수기로 입자크기 분포를 측정하여 각 구성요소의 입자제거효율을 구하였다. 실험결과로부터 기수분리기에서는 입경이 $5{\mu}m$ 이상인 조대 입자가 주로 제거되고. 중성능 필터에서는 이보다 작은 미세 입자가 주로 제거됨을 알 수 있었다. 유해가스 제거 실험에서는 시험용 가스를 송풍기의 출구에 주입하여 공기청정기의 상류와 기수분리기의 하류에서 가스농도를 측정하여 유해가스 제거효율을 구하였다. 실험결과로부터 헨리상수가 큰 수용성인 $SO_2$, HCHO 및 $NH_3$는 제거효율이 높았으나, 헨리상수가 낮아 난용성인 NO와 $NO_2$는 제거효율이 낮음을 알 수 있었으며, 공기청정기에서 상당량의 음이온이 발생됨을 알았다.

• 한국환경보건학회지
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• 제47권5호
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• pp.384-397
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• 2021

Background: With volatile organic compounds (VOCs) containing aromatic and halogenated hydrocarbons such as benzene, toluene, and xylene that can adversely affect the respiratory and cardiovascular systems when a certain concentration is reached, it is important to accurately evaluate the source and the corresponding health risk effects. Objectives: The purpose of this study is to provide scientific evidence for the city of Seoul's VOC reduction measures by confirming the risk of each VOC emission source. Methods: In 2020, 56 VOCs were measured and analyzed at one-hour intervals using an online flame ionization detector system (GC-FID) at two measuring stations in Seoul (Gangseo: GS, Bukhansan: BHS). The dominant emission source was identified using the Positive Matrix Factorization (PMF) model, and health risk assessment was performed on the main components of VOCs related to the emission source. Results: Gasoline vapor and vehicle combustion gas are the main sources of emissions in GS, a residential area in the city center, and the main sources are solvent usage and aged VOCs in BHS, a greenbelt area. The risk index ranged from 0.01 to 0.02, which is lower than the standard of 1 for both GS and BHS, and was an acceptable level of 5.71×10^-7 to 2.58×10^-6 for carcinogenic risk. Conclusions: In order to reduce the level of carcinogenic risk to an acceptable safe level, it is necessary to improve and reduce the emission sources of vehicle combustion and solvent usage, and eco-car policies are judged to contribute to the reduction of combustion gas as well as providing a response to climate change.