• Environmental Analysis Health and Toxicology
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• 제21권1호
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• pp.45-56
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• 2006

This study was conducted to investigate seasonal distributions of fine particles ($PM_{2.5}$) and associated polycyclic aromatic hydrocarbons (PAHs) at three cities. $PM_{2.5}$ samples were collected on glass fiber filters at urban (Chuncheon), metropolitan (Seoul), and industrial complex sites (Ulsan) from September, 2002 to February, 2004 using the Andersen FH 95 Particulate Sampler. About five 24-hour samples were collected from each site per season. The filters were analyzed for mass and six selected PAHs concentrations. $PM_{2.5}$ concentrations were the highest either in winter or spring, which could be attributed to the increase of fossil fuel combustion in winter or the transport of yellow sand to the Korean peninsula from China in spring, respectively. Regional $PM_{2.5}$ concentrations were higher in the order of Seoul>Chuncheon>Ulsan without statistical difference among cities. The filters were extracted using dichloromethane in an ultrasonicator and analyzed for six PAHs (anthracene, fluoranthene, pyrene, benzo[a]anthracene, chrysene, and benzo[a]pyrene) with HPLC. Total PAHs concentrations were statistically different among seasons in each site, and the highest concentrations were observed in winter at each sampling site. For total samples collected, the median total PAHs concentrations in Chuncheon ($4.6ng/m^3$) and Seoul ($4.4ng/m^3$) were approximately two times higher than that in Ulsan ($2.1ng/m^3$). Chrysene was a component found in the highest proportion among total PAHs at each site. Carcinogenic risks calculated based on the BaP toxic equivalency factors (TEFs) over the whole sampling period were higher in the order of Chuncheon>Seoul>Ulsan. This study suggests that the atmosphere of Chuncheon is contaminated with particulate matter and PAHs at the levels equivalent to those of Seoul and that an appropriate measure needs to be taken to mitigate human health risks from inhalation exposure to airborne fine particles.

• 한국해안·해양공학회논문집
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• 제25권3호
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• pp.165-171
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• 2013

조차가 큰 해역에서 조위편차 역시 크게 나타나고 있음은 조위편차 내에 조석성분이 남아있음을 의미한다. 상관관계함수를 통한 분석을 시행한 결과에서도 서해안 해역에서 조석주기 부근의 자기상관계수가 크게 나타나고 있어 이러한 사실을 뒷받침하고 있다. 조위편차의 단주기성분에 해당하는 이러한 조석관련성분을 분석하기 위하여 웨이블릿분석을 시행하였다. 분석 결과에 의하면 조차가 클수록 조석주기성분이 크게 나타나고 있으며 단주기 성분에서 계절별 변화가 심하지 않다는 점과 목포의 경우 천해조성분인 6시간 주기성분이 유독 크게 나타나고 있다는 점에서 단주기 성분과 조석관련성분의 관련성을 연관지을 수 있다. 이와 함께 24시간 이내 단주기 성분의 조위편차는 조석예측오차 및 조석-해일 비선형성 등에 주로 기인하고 있는 것으로 파악되었다. 이러한 조석변조해일성분은 조석자체에 기인하므로 기상조 성분인 해일고와는 구분되어야 한다.

• 한국환경보건학회지
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• 제39권3호
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• pp.223-229
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• 2013

Objectives: In an effort to examine the distribution of THMs (Trihalomethane) generated from chlorine disinfection by the drinking water treatment plants located on the east coast region of Gangwon-do, this study surveyed the distribution and concentrations of each component of THMs twice per month for 5 years from 2008 to 2012. Fluctuation pattern in the seasonal generation amount was identified. In addition, the correlation between the concentration of organic substances in water and THMs was assessed, along with stability of purified water quality supplied by the water treatment plants on the east coast by analyzing the composition ratio of each component that constitutes THMs and the detection frequency. Method: The research was done on purified water supplied by 29 water treatment plants in 7 cities and counties (Goseong-gun, Sokcho-si, Yangyang-gun, Gangneung-si, Donghae-si, Samcheok-si, Taebaek-si) located in Gangwon-do on the east coast. Water samples were collected twice a month from 2008 to 2012 and were investigate for chloroform, bromodichloromethane (BDCM), dibromochloromethane (DBCM), and bromoform, based on analysis through Purge-Trap (Tekmar 3000) devices using FID-attached GC (HP 6890, Hewlett Packard). Result: THMs concentration detected at Gangneung-si was 0.0086mg/L, Goseong-gun 0.0019mg/L, Donghae-si 0.0099 mg/L, Samcheok-si 0.0016 mg/L, Sokcho-si 0.0057 mg/L, Yangyang-gun 0.0027 mg/L and Taebaek-si 0.0038 mg/L. As the THMs composition rate, chloroform constitutes 51.4% followed bybromodichloromethane 22.3%, bromoform 15.2% and dibromochloromethane 11.1% respectively. Conclusion: Throughout the entire THMs survey areas and period, the maximum concentration was 0.072mg/L, which did not exceed the water quality standards (0.1 mg/L), and the overall average concentration was very low at 0.0044 mg/L.

• 한국환경복원기술학회지
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• 제18권4호
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• pp.15-27
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• 2015

The objectives of this study are to analyze the quantitative ecological principal components of Korean Peninsula using the multivariate spatial environmental datasets and to compare the ecological difference between South and North Korea. Ecological maps with GIS(Geographical Information System) are constructed by PCA(Principal Component Analysis) based on seventeen raster(cell based) variables at 1km resolution. Ecological differences between South and North Korea are extracted by Factor Analysis using ecosystem maps masked from Korean ones. Spatial data include SRTM(Shuttle Radar Topography Mission), Temperature, Precipitation, SWC(Soil Water Content), fPAR(Fraction of Photosynthetically Active Radiation) representing for a productivity, and SR(Solar Radiation), which all cover Korean peninsula. When it performed PCA, the first three scores were assigned to red, green, and blue color. This color triplet indicates the relative mixture of the seventeen environmental conditions inside each ecological region. The first red one represents for 'physiographic conditions' worked by high elevation and solar radiation and low temperature. The second green one stands for 'seasonality' caused by seasonal variations of temperature, precipitation, and productivity. The third blue one means 'wetness condition' worked by high value such as precipitation and soil water contents. FA extraction shows that South Korea has relatively warm and humid ecosystem affected by high temperature, precipitation, and soil water contents whereas North Korea has relatively cold and dry ecosystem due to the high elevation, low temperature and precipitation. Results would be useful at environmental planning on inaccessible land of North Korea.

• 천문학회보
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• 제37권2호
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• pp.116.1-116.1
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• 2012

When an interplanetary (IP) shock passes over the Earth's magnetosphere, the geosynchronous magnetic field strength near the noon is always enhanced, while the geosynchronous magnetic field near the midnight decreases or increases. In order to understand what determines the positive or negative magnetic field response at nightside geosynchronous orbit to sudden increases in the solar wind dynamic pressure, we have examined 120 IP shock-associated sudden commencements (SC) using magnetic field data from the GOES spacecraft near the midnight (MLT = 2200~0200) and found the following magnetic field perturbation characteristics. (1) There is a strong seasonal dependence of geosynchronous magnetic field perturbations during the passage of IP shocks. That is, the SC-associated geosynchronous magnetic field near the midnight increases (a positive response) in summer and decreases (a negative response) in winter. (2) These field perturbations are dominated by the radial magnetic field component rather than the north-south magnetic field component at nightside geosynchronous orbit. (3) The magnetic elevation angles corresponding to positive and negative responses decrease and increase, respectively. These field perturbation properties can be explained by the location of the cross-tail current enhancement during SC interval with respect to geosynchronous spacecraft position.

• 한국군사과학기술학회지
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• 제16권4호
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• pp.545-552
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• 2013

This paper is a part of developing a computer code that can be used to generate IR images of a naval ship by considering the emitted and reflected infrared signals. The spectral radiance received by an IR sensor is consisted of the self-emitted component from the ship surface, the reflected component of the solar/sky irradiance at the ship surface, the emitted radiance from the ship surface and the exhaust plume gas, and the scattered radiance by the atmosphere. The plume gas radiance occupies a large part of the emitted radiance from a naval ship in operation. Therefore plume gas radiance must be taken into account when calculating the radiance from a naval ship for reliable IR images. In this paper, IR images of a naval ship with the exhaust gas effect in various environmental conditions are generated by using an exhaust gas prediction model called the JPL model. The contrast radiance (CR) values of the IR images are calculated to analyze the effect of the exhaust gas radiance quantitatively. The results obtained by quantitative analysis show that the IR signatures with the exhaust plume gas are 2.26 times larger than those neglecting the plume gas effect. The effect of the exhaust plume gas is shown to be more eminent in winter than in summer in the daytime.

• 한국물환경학회지
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• 제37권6호
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• pp.520-530
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• 2021

Multivariate statistical analysis and an environmental hydrological model were applied for investigating the causes of water pollution and providing best management practices for water quality improvement in urban and agricultural watersheds. Principal component analysis (PCA) and cluster analysis (CA) for water quality time series data show that chemical oxygen demand (COD), total organic carbon (TOC), suspended solids (SS) and total phosphorus (T-P) are classified as non-point source pollutants that are highly correlated with river discharge. Total nitrogen (T-N), which has no correlation with river discharge and inverse relationship with water temperature, behaves like a point source with slow and consistent release. Biochemical oxygen demand (BOD) shows intermediate characteristics between point and non-point source pollutants. The results of the PCA and CA for the spatial water quality data indicate that the cluster 1 of the watersheds was characterized as upstream watersheds with good water quality and high proportion of forest. The cluster 3 shows however indicates the most polluted watersheds with substantial discharge of BOD and nutrients from urban sewage, agricultural and industrial activities. The cluster 2 shows intermediate characteristics between the clusters 1 and 3. The results of hydrological simulation program-Fortran (HSPF) model simulation indicated that the seasonal patterns of BOD, T-N and T-P are affected substantially by agricultural and livestock farming activities, untreated wastewater, and environmental flow. The spatial analysis on the model results indicates that the highly-populated watersheds are the prior contributors to the water quality degradation of the river.

• 한국환경과학회지
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• 제32권4호
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• pp.243-257
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• 2023

This study was conducted to investigate the distribution characteristics, source identification, and health risk of polycyclic aromatic hydrocarbons (PAHs) present in particulate matter 10 (PM-10), in Gwangju. PM-10 samples were collected from September 2021 to August 2022 from three sampling sites, one located in each of the following areas: green, residential, and industrial. The average concentrations of PAHs were found to be higher in the industrial area (9.75±6.51 ng/㎥) than in the green (6.90±2.41 ng/㎥) and residential (6.74±2.38 ng/㎥) areas. Throughout the year and across all sites, five-ring PAHs accounted for the largest proportion (29.8-34.5%) of all PAHs. The concentrations of PAHs showed distinct seasonal variations, with the highest concentration observed in winter, followed by autumn, spring, and summer. Source apportionment analyses were performed using diagnostic ratios and principal component analyses, which indicated that coal/biomass combustion and vehicle emissions were the primary sources of PAHs in PM-10. The incremental lifetime cancer risk was estimated for all age groups at all sampling sites, and the results revealed a much lower risk level than the standard acceptable risk level (1×10^-6).

• 한국수산과학회지
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• 제35권1호
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• pp.35-45
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• 2002

피조개 양식장으로 이용되고 있는 남해 연안의 진주만에서 저서 다모류 분포를 밝히기 위하여 van Veen grab 채니기를 이용하여 1999년 8월부터 2000년 5월 사이에 계절별로 4회에 걸쳐 저서동물을 채집하였다. 조사기간 중 총 132종의 저서 다모류가 채집되어, 출현한 전체 저서동물 개체수 중 약 $80\%$를 차지하였다. 다모류의 평균 출현 개체수는 계절별로 뚜렷한 차이를 나타내지 않았으나 생체량은 여름 (8월)에 가장 높았던 반면, 종 다양도와 풍도는 여름철에 가장 낮았다. 이것은 계절에 따른 종조성 변동에 의한 다모류 군집 차이를 반영하는 것으로, 이와 같은 계절변동은 봄철에 소형의 몇몇 r-선택성 기회종과 여름철에 서관을 만드는 Mal-danidae과 종의 출현에 기인하였다. 한편, Capitella Capitata, No-tomastus latericeus 및 Lumbrineris sp.와 같이 유기물이 풍부한 해역에서 흔히 출현하는 종들이 만 전체적으로 연중 높은 밀도를 나타내었다. 남부의 피조개 양식장 수역은 상대적으로 낮은 개체수와 생체량을 나타내었는데, 종 다양도와 풍도 역시 상대적으로 낮은 경향을 보였다. 주성분 분석의 결과는 만내 다른 수역에서 우점하는 Maldanidae과는 물론 소형 기회종의 출현 빈도가 피조개 양식장 수역에서 대단히 낮아 피조개 양식장 수역 저서 다모류 군집이 인근 나머지 정점군들의 군집과 뚜렷이 구분된다는 것을 잘 보여주었다. 다모류 군집의 공간변동은 피조개 양식장 수역 퇴적물의 더욱 세립한 입도 조성과 높은 황화물 농도 및 북부 일부 정점의 낮은 염분 등에 의해서 부분적으로 설명될 수 있었지만, 다른 환경 변수에서 이와 같은 차이는 뚜렷하지 않았다. 진주만에서 다모류 군집의 공간분포는 오히려 봄철에 피조개 채취를 위한 퇴적물의 물리적 교란에 의해 크게 영향을 받는 듯 하였다. 않고 사육조 수면으로 공급되는 우회량이 많을 경우 용존산소는 증가하였으나 수처리 장치로 공급되는 유량이 작아 부유 고형물, 유기물 등의 수질 인자가 악화되는 현상을 보였다.대된다.. 창란젓갈 저장시 품질측정변수에 대한 상관관계를 조사한 결과병포장에서는 용기내 압력, pH, L값, VBN, 관능검사 등이 상관관계가 높아 젓갈 포장에서 품질지표항목으로 이용할 수 있을 것으로 기대된다.는 0.1 mM과 0.4 mM 및 0.8 mM 배양구는 배양 5시간 후에 최대값이 되어 각각 $204\%$, $198\%$ 및 $191\%$로 증가하였다. 이처럼 BNF나 PB, MC는 명주조개에서도 미크로좀의 CYP 함량과 EROD 활성을 증가시키는 유도효과를 나타내었으며, 특히 MC에 의한 유도효과가 가장 강했고 BNF, PB의 순이었고, 대체로 약물의 농도가 높을수록 유도 효과도 큰 경향을 보였다.이 한국어와는 다른 것이라거나, 한국어 음성학을 공부하지 않고 한국어를 연구할 수 있다는 뜻은 아닙니다. 의학에도 분야마다 전문의가 있듯이, 언어학도 이제 복잡하고 광범한 학문이 되었으므로 분야별로 전문가가 나오게 된 것뿐입니다. 따라서 "나는 통사론에 관심이 있으므로 소리말에는 관심이 없다"고 말하는 언어학자가 있다면, 이 것은 크게 잘못된 것입니다. 마찬가지로 "나는 소리에만 관심이 있으므로 통사론에는 관심이 없다"고 말하는 음성학자가 있다면, 이 또한 안되는 일입니다. 문의 구성과 어휘 요소와 아무 관련이 없는 말소리의 차이가 무슨 소용이 있으며, 통사 구조를 표현하고 저달하는 말소리를 연구하지 않고 어떻게 통사론을 연구할 수 있겠습니까? 다시 간추리면, 언어는 본질적으로 소리말이고, 언어의 특성과 사용 및 습득도 모두 소리말 형태로 나타납니다. 따라서, 영국의 대학은 음성학이 대단히 중요함을 인식하고, 언어학을 올바르게

• Journal of Forest and Environmental Science
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• 제29권1호
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• pp.38-48
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• 2013

Decomposition of plant material is an important component in the study of forest ecosystem because of its critical role in nutrient cycling. Different tree species has different nutrient release patterns, which are related to leaf litter quantitative traits and seasonal environmental factors. The quantitative traits of leaf litter are important predictors of decomposition and decomposition rates increase with greater nutrient availability in the forest ecosystems. At the ecosystem level, litter quantitative traits are most often related to the physical and chemical characteristics of the litter, for example, leaf toughness and leaf mass per unit area, and lignin content tannin and total phenolics. Thus, the analysis of litter quantitative traits and decomposition are highly important for the understanding of nutrient cycling in forest ecosystems. By studying the role of litter quantitative traits on decomposition and nutrient cycling in forest ecosystems will provide a valuable insight to how quantitative traits influence ecosystem nutrient dynamics. Such knowledge will contribute to future forest management and conservation practices.