• 한국대기환경학회지
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• 제18권3호
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• pp.193-204
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• 2002

To investigate the relationships between the atmospheric concentrations of PCBs and temperature, quantity of both parameters was performed at an urban site in Korea from July 1999 to January 2000. The strength of correlations between total PCB and temperature was found to be significant (r = 0.752, p < 0.001). It hence indicates that total PCB contents were affected sensitively by temperature change during the sampling period. The ratio of PCB homologs and Deca-CB(PCB 209) also behaved quite similarly to the change of temperature (r>0.60, p<0.05). This may be inferable with the progress of the gas/particle partitioning to the gas phase, especially for fri-and tetra-CBs. Because they have high vapor pressure, they generally exist in the gas phase. The Clausius-Clapeyron equation was applied to the atmospheric PCB data, relating PCB partial vapor pressure to inverse temperature. This may essentially represent the temperature-controlled transition between condensed phase and atmospheric gas phase. The slopes of the resulting plot with International Council for the Explanation of the Seas (ICES) congener ranged from -2810 to -5887, with significantly steep slope and $R^2$(p< 0.005) It was inferred that the PCB atmospheric concentration was also affected by change in the surrounding conditions such as soil, lakes and trees.

• 대한환경공학회지
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• 제31권12호
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• pp.1151-1160
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• 2009

전세계적으로 과불화 화합물들에 의한 오염은 심각한 수준에 도달해 있다. 이들은 난분해성으로 환경에 장기간 머물며 생물축적 (bioaccumulation) 및 생물확대 (biomagnification)의 원인 물질로 인간과 동물들에게 심각한 피해를 유발한다. 또한, 이들은 광분해, 생물분해 및 화학적인 분해에도 매우 큰 내성을 가지고 있기 때문에 상 하수 처리공정에서 과불화 화합물에 대한 제거율이 낮다. 국내의 경우는 아직까지 주요 하천과 호소에서의 이들의 오염현황에 대한 변변한 조사나 연구보고도 없는 실정이다. 본 논문에서는 과불화 화합물들에 대한 국내에서의 관심을 고조시키기 위해 과불화 화합물의 종류 및 유래, 위해성, 상수와 하수에서의 거동 및 처리공정으로 나누어 과불화 화합물들에 대해 간략하게 기술하였다.

• 한국농공학회지
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• 제45권7호
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• pp.38-48
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• 2003

Lake water quality assessment information is useful to anyone involved in lake management, from lake owners to lake associations. It provides lake water quality criteria, which can improve the ways how to manage out lake resources and how to measure current conditions. It also provides a knowledge base so that the lakes can be protected and restored. Here, the Freshwater Lake Water Quality Management System(FLAQUM) was developed. The results of FLAQUM application by scenario proved that pollutant load at rainfall by the nonpoint sources was much more than normal times at rainfall. From the result of Scenario I (pollutant source increase case), the concentrations of Boryeong freshwater lake were BOD 9.43mg/L, T-N 4.53 mg/L and T-P 0.21 mg/L, respectively, and those values exceed the standard of agricultural water. And in case of Scenario I and II(the present case) excluding Scenario III (pollutant source decrease case), all of T-N and T-P are either mesotrophication or eutrophication, on the other hand when 60% of pollution source is removed, the concentrations of Scenario III were BOD 3.21 mg/L, T-N 0.95 mg/L, T-P 0.11 mg/L, respectively, and which satisfies the standard of agricultural water quality.

• 한국제4기학회지
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• 제17권2호
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• pp.75-78
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• 2003

This study is conducted to examine the solar radiation features of landscape in Eastern Mongolia and their space and time distribution characteristics. To many foreigners, the name Mongolia conjures up images of the vast steppes of Central Asia. And, indeed, the extensive grasslands of the steppe make up the heart of Mongolia-geographically and economically. Steppe covers nearly the entire far eastern part of Mongolia, extending west in a narrowing band just south of the Khangai and Khan Khokhii mountains all the way to the Depression of the Great lakes. Eastern Mongolia is recognized as one of the last remaining untouched grassland steppes in the world. Landscape of Eastern Mongolia divided by 19 types that belongs to High Mountain, Middle Mountain and low mountain steppe. Only 5.6% of the total land area is covered by forest. Eastern Mongolian steppe is homeland of migratory rare and endangered birds and about 2.0million freely migrating gazelles. According to Mongolian scientists, there is growing evidence of fundamental changes in the Eastern steppe ecosystems in terms of increasing aridity during the last 70 years. As estimated average annual temperature has increased by approximately 0.7oC, soil moisture, energy supply has been changing. These processes closely interrelated into water and energy cycle of steppe ecosystem.

• 한국농촌건축학회논문집
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• 제20권3호
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• pp.1-9
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• 2018

This research aimed to identify walking trails' purpose of its use and the factors that influence the selection. For this, a survey targeting the walking trail users was conducted in 2016 to question the research aim stated above. The mean number of walking trail usage in a month was 2.51 times and the duration of use ranged from one to ten hours, with the average of 2.5 hours. The main reason for the usage was to maintain physical health and the following was for mental relaxation, thus showing more than 90% of the people concerned with physical and mental health. Walking trails near the residences had the greatest percentage and trails that include mountains, rivers, seas and lakes were the following. Trails near historical locations or countryside showed a lower percentage. The choices showed relevance to the proximity as a standard of selection. The next highest percentage was the convenience of transportation. Additionally, people that access the trails three or more times were inclined to be influenced by the installation of exercising equipment. The aspect of facilities showed that the place for relaxation was a significant selection factor such as bathrooms for 20s to 30s and exercising equipments for people older than 50. To access the walking trails, people reach it by automobiles, public transport, walking and bicycles and out of these, automobiles had the highest percentage.

• 한국정보통신학회논문지
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• 제8권5호
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• pp.970-976
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• 2004

본 논문에서는 MRC(Maximal Ratio Combing) 결합 기법을 사용한 RAKE 수신기에서 채널 추정 알고리즘에 따른 성능을 분석한다. 채널 추정 알고리즘에는 WMSA(Weighted Multi-Slot Averaging), 동일 이득 채널 추정 (Equal Cain Estimation ; ECE), 심볼 단위 채널 추정(Symbol-to-Symbol Estimation ; SSE)의 세 가지가 있는데 상업용 시뮬레이션 틀인 HP사의 ADS를 이용하여 비동기 방식 IMT-2000시스템(3GPP)을 대상으로 성능을 분석한다. 성능 분석을 위해서 본 논문은 Jakes 페이딩 채널 모델을 사용한다. 모의실험 결과를 통하여, 저속 도플러(3Km/h)일 때 WMSA 알고리즘이 다른 알고리즘 성능보다 더 좋음을 알 수 있다. 그러나 고속 도플러(120Km/h)일 때, 간단한 구조를 갖는 ECE 알고리즘이 보다 더 유용함을 알 수 있다.

• 환경위생공학
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• 제14권4호
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• pp.77-84
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• 1999

Most river quality problems are generated by pollutants which are discharged into the river as a consequence of human activities. And eutrophication occurs when water is over enriched with nutrients, principally nitrate and phosphate. Both these nutrients are found in many waste products, especially sewage even when the waste is treated. Eutrophication is concerned in lakes, but it also causes problems in river. Wide growth of Phytoplankton in rivers, leads to blockage of channels, but the main concern is deoxygenation because of the increase in plant life's demand for oxygen in revers. Fish, plant and animals die due to lack of oxygen. The increase of algae floating on the tops of water looks ugly and has attracted public attention and concern in recent years. One way of controlling eutrophication is to restrict the amount of waste carrying nitrate or phosphate from entering the water in the first place. another way is to remove it from the water after it has been entered. This study was carried out to investigate on the trophic state, nutrients and Chlorophyll-a concentration in the Han River. The results were as follows:1. Concentrations of total nitrogen were 2.208~9.221(5.133)mg/$\ell$2. Concentrations of total phosphate were 0.045~0.614(0.195)mg/$\ell$3. Chlorophyll-a concentration were $0.0-25.3(9.6)mg/m^3$.4. The correlation coefficient between T-P and Chlorophyll-a concentration was r=-0.856 at Sungsan sampling site.5. The correlation coefficient was r=-0.578~-0.767, between Paldang Dam outflow and Chlorophyll-a concentration at all sampling sites.

• 한국물환경학회지
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• 제28권2호
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• pp.178-184
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• 2012

BOD decay rate is a key parameter of BOD-DO models in streams and lakes. In the calibration of water quality modeling appropriate range of coefficient is required for guidance of parameter selection. In this study BOD decay rate was measured at 48 stream sites and 10 reservoir sites in 8 different river systems. The decay rate ranged from 0.09 to 0.25 $day^{-1}$ with a mean of 0.16 $day^{-1}$. Among river systems the decay rates showed significantly different ranges, with the Han River system showing higher values than other river systems. In comparing different types of water bodies, the decay rate was slightly higher in tributaries than in reservoirs and mainstreams. Our results can provide guidance to the selection of proper coefficient for various water bodies in the calibration of water quality models.

• 물과 미래
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• 제29권5호
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• pp.235-244
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• 1996

호수에서의 수직온도분포를 모의하기 위하여, 수리학적 특성 즉 유속분포가 필요없는 일차원 와확산모델 및 혼합층모델이 개발, 적용되었으며 각 모델의 결과가 비교, 검토되었다. 전자는 지배방정식 유도시 분자확산을 모델적용시 년간 수면변화를 무시했으며, 후자는 간단한 해석을 위하여 일정한 층의 두께를 가정하였다. 호수표면과 바닥에서의 온도경계조건이 각각 열 에너지의 이동에 의해서 결정되도록 하는 와확산모델은 explicit 유한차분법을, 두층을 이용하는 혼합층모델은 Runge-Kutta 방법을 사용하였다. 측정된 데이타와 와확산모델 및 혼합층모델의 계산치와 비교해본 결과, 만족한 결과를 도출하였다. 따라서, 호수관리의 수단으로 이 모델들을 유용하게 이용할 수 있을 것으로 사료된다.

• 한국자원식물학회:학술대회논문집
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• 한국자원식물학회 2018년도 추계학술대회
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• pp.42-42
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• 2018

Two unrecognized species of Sparganium of Korea were found during the our field expeditions and phylogenetic analyses of specimens deposited in the Herbarium of Korea National Arboretum (KH). S. coreanum H. $L{\acute{e}}v$. was first reported as a new species based on the specimen (Taquet, 2150) collected from Jeju Island. It has been recognized as synonym or infraspecific taxa of S. stoloniferum and S. eurycarpum or even never recognized recently. However, phylogenetic tree showed that S. coreanum is monophyletic and has sister relationship with S. eurycarpum. Furthermore, additional distribution localities were also found by herbarium survey. Morphological characteristics and distribution information of S. coreanum will be discussed. Another Sparganium species found from Mt. Daeam is occurring either as floating or emergent. Although we could not identify this species since lack of any flowers or fruits for two year surveys, phylogenetic analyses results showed that this species belong to the clade of S. glomeratum, which is distributed in high elevation lakes and marshes of Europe, Asia, and North America. Additional survey of morphology and report will be needed.