• 한국환경생태학회지
• /
• 제26권5호
• /
• pp.719-729
• /
• 2012

백두대간은 남한구간만 약 670km로 전체 지역에 대한 생태적 특성을 파악하기는 어려워 각 지역에 대한 상세한 연구가 지속적으로 수행되어야 한다. 이에 본 연구는 백두대간 구간 중 댓재에서 백봉령구간의 식생구조를 밝히고 향후 복원 및 관리계획 수립시 필요한 기초자료를 제시하고자 마루금을 중심으로 $10m{\times}10m(100m^2)$ 조사구 40개소를 설치하였다. TWINSPAN에 의한 군집분류 결과 구상나무군집, 소나무 우점군집, 신갈나무 우점군집, 일본잎갈나무 우점군집 등 8개로 유형화되었다. 구상나무군집과 소나무군집은 신갈나무와의 경쟁을 회피할 수 있는 능선부 또는 암반지대에 분포하였으나 낙엽활엽수와의 경쟁으로 쇠퇴할 가능성이 높아 보호의 필요성이 있었다. 단위면적당($400m^2$) 종다양도는 0.8046~1.1283이었으며 단일종 우점군집이 낮고 경쟁상태인 군집은 높은 것으로 나타났으며 대부분 층위구조가 형성된 보호가치가 있는 숲이었다.

• 한국물환경학회지
• /
• 제35권6호
• /
• pp.580-588
• /
• 2019

The flow of the middle and downstream of the Yeongsan River is stagnant by two weirs of Seungchon and Juksan and the estuary dam and maintained in freshwater. In this study, the Environmental Fluid Dynamics Code-National Institute of Environment Research(EFDC-NIER) model was applied to the Yeongsan River to simulate water flow, temperature, and salinity stratification. The EFDC-NIER model is an improved model which can simulate multi-functional weirs operation, multiple algal species, and the vertical movement mechanism of algal based on the EFDC model. The simulation results for the water level, water temperature, velocity, and salinity reproduced the observed values well. The mean absolute error(MAE) of the model calibration in the annual variations of the water level was 0.1-0.3 m, water temperature was 0.8-1.7 ℃, velocity was 4.5-7.1 cm/sec, and salinity was 1.5 psu, respectively. In the case of scenario simulation for the full opening of the estuary dam, the water level of the estuary dam was directly impacted by the tide so it was predicted to rise - 1.35 m to 0.2 m on average sea level. The velocity was also predicted to increase from 2.7 cm/sec to 50.8 cm/sec, and the flow rate to increase from 53 ㎥/sec to 5,322 ㎥/sec.

• 한국환경과학회지
• /
• 제15권2호
• /
• pp.121-131
• /
• 2006

Atmospheric bulk (wet and dry) samples were monthly collected in Masan and Heangam areas of Korea, to assess the deposition flux and seasonal variation of polycyclic aromatic hydrocarbons (PAHs). Deposition fluxes of PAHs in bulk samples were determined using gas chromatography coupled to mass spectrometer detector (GC/MSD). Particle deposition fluxes from Masan and Haengam areas varied from 13 to $87\;g/m^2/year$ and from 5 to $52\;g/m^2/year$, respectively. PAHs deposition fluxes in atmospheric bulk samples in Masan and Haengam areas ranged from 135 to $464\;{\mu}g/m^2/year$ and from 62.2 to $194\;{\mu}g/m^2/year$, respectively. Atmospheric deposition fluxes of particles and PAHs in this study were comparable to or slightly lower values than those from different locations in Korea and other countries. PAHs profiles of atmospheric deposition bulk samples showed slightly different from two sampling areas, however the predominant species of PAHs were similar. Indeno (1,2,3-c,d)pyrene, benzo(g,h,i)perylene, phenanthrene compounds were the most detected PAHs in deposition bulk samples. Carcinogenic PAHs occupied the contribution of approximately $30-40\%$ of the total PAHs deposition fluxes. The non-metric multi-dimensional scaling (MDS) was used, to assess the differentiation of PAHs source between two sampling areas. The result suggests that PAHs contamination sources were different according to the location and season surveyed. There was no an apparent relationship between the PAHs deposition flux against temperature and rainfall amount, even though summer season with the highest temperature and the largest amount of precipitation showed the lowest PAHs deposition flux. Benzo(e)pyrene/benzo(a)pyrene ratio indicated that the photo-degradation process was one of important factors to the seasonal variation of PAHs with the lower deposition fluxes.

• Journal of Ecology and Environment
• /
• 제34권2호
• /
• pp.175-191
• /
• 2011

Colonization patterns and community changes in benthic macroinvertebrates in the Cheonggye Stream, a functionally restored stream in downtown Seoul, Korea, were studied from November 2005 to November 2007. Benthic macroinvertebrates were quantitatively sampled 15 times from five sites in the stream section. Taxa richness (59 species in total) increased gradually over the first year, whereas the density revealed seasonal differences with significantly lower values in the winter season and after flood events. The benthic macroinvertebrate fauna may have drifted from the upstream reaches during floods and from the Han River, arrived aerially, or hitchhiked on artificially planted aquatic plants. Oligochaeta, Chironommidae, Psychodidae, and Hydropsychidae were identified as major community structure contributors in the stream. Swimmers and clingers colonized relatively earlier in the upper and middle reaches, whereas burrowers dominated particularly in the lower reaches. Collector-gatherers colonized at a relatively early period throughout the stream reaches, and collector-filterers, such as the net-spinning caddisfly (Cheumatopyche brevilineata), predominated in the upper and middle reaches after a 1-year time period. Cluster analyses and multi-response permutation procedures demonstrated that the Cheonggye Stream shares more similarities with the Jungnang Stream than with the Gapyeong Stream. Detrended correspondence analysis and nonmetric multidimensional scaling demonstrated that physical environmental factors (depth, current velocity, dissolved oxygen, and pH) as well as nutrients (total nitrogen and total phosphorous), water temperature, and conductivity could affect the distribution of benthic macroinvertebrates in the study streams.

• 한국환경복원기술학회지
• /
• 제2권1호
• /
• pp.58-65
• /
• 1999

The purpose of this study was to evaluate the effect of rehabilitation measures on the fired woodland of Chesuk-bong in Mt. Chiri through the vegetation structure and comparison of growth pattern between natural seedlings and transplanted Abies koreana seedlings. It was also discussed the rate of standing and fallen trees of dead conifers in the management strategy for vegetation regeneration and protection of sub-alpine area. In this fired woodland, shrub layers consisting of Weigela subsessilis, Sambucus williamsii var. coreana, Rhododendron schlippenbachii, R. mucronulatum, Tripterygium regelii, and etc. were gradually expanded, and tree species such as Betula ermani, Sorbus commixta, Acer pseudosieboldianum, and Malus baccata var. mandshurica were also regenerated. The growth of height and crown width of Abies koreana seedlings transplanted for vegetation regeneration were a little lower than those of natural seedlings. The seedlings of A. koreana transplanted in this fired woodland grew about 50.6% normally, but the others had multi-branched or growth stopped by death of terminal shoot. Because the number of dead conifers by fire tend to be gradually increased as time passed, it can occurs to the soil erosion and landslide by weakness of the cohesion and resistance of soil. Therefore, it is consider that rehabilitation measures projects of the fired woodland in subalpine area may be more prevention a natural disaster like soil erosion, flood and landslide.

• 한국대기환경학회지
• /
• 제28권4호
• /
• pp.384-395
• /
• 2012

This study was performed to develop the source profiles for fine particles ($PM_{2.5}$) emitted from the biomass burning. The multi-method research strategy included a usage of combustion devices such as field burning, fireplace, and residential wood burning to burn rice straw, fallen leaves, pine tree, and oak tree. The data were collected from multiple sources and measured water-soluble ions, elements, elemental carbon (EC), and organic carbon (OC). From this study, it turned out that OC (34~67%) and EC (1.2~39%) are the major components emitted from biomass burning. In the case of burning rice straw at field burning, OC (66.6%) was the most abundant species, followed by EC (4.3%), $Cl^-$ (3.6%), Cl (2.1%), and $SO^{2-}_4$(1.9%). Burning rice straw, fallen leaves, pine tree, and oak tree at fireplace, the amount of OC was 58.5%, 52.7%, 52.5%, and 61.2%, and that of EC was 1.2%, 18.4%, 36.5%, and 2.7%, respectively. The ratio of OC for the burning of pine tree and oak tree from the residential wood burning device was 56.9% and 34.3%, and that of EC was 25% and 38.6%, respectively. Applying the measured data with respect to the proportion of components emitted from biomass burning to reference model, it turned out that self-diagnosed result was appropriate level, and the result based on the model is in highly corresponding to actual timing of biomass burning.

• Biomolecules & Therapeutics
• /
• 제24권4호
• /
• pp.438-445
• /
• 2016

Cyperi Rhizoma (CR), the rhizome of Cyperus rotundus L., exhibits neuroprotective effects in in vitro and in vivo models of neuronal diseases. Nevertheless, no study has aimed at finding the neuroactive constituent(s) of CR. In this study, we identified active compounds in a CR extract (CRE) using bioactivity-guided fractionation. We first compared the anti-oxidative and neuroprotective activities of four fractions and the CRE total extract. Only the ethyl acetate (EA) fraction revealed strong activity, and further isolation from the bioactive EA fraction yielded nine constituents: scirpusin A (1), scirpusin B (2), luteolin (3), 6'-acetyl-3,6-diferuloylsucrose (4), 4',6' diacetyl-3,6-diferuloylsucrose (5), p-coumaric acid (6), ferulic acid (7), pinellic acid (8), and fulgidic acid (9). The activities of constituents 1-9 were assessed in terms of anti-oxidative, neuroprotective, anti-inflammatory, and anti-amyloid-${\beta}$ activities. Constituents 1, 2, and 3 exhibited strong activities; constituents 1 and 2 were characterized for the first time in this study. These results provide evidence for the value of CRE as a source of multi-functional neuroprotectants, and constituents 1 and 2 may represent new candidates for further development in therapeutic use against neurodegenerative diseases.

• 한국진공학회지
• /
• 제18권3호
• /
• pp.164-175
• /
• 2009

전산 유체 역학 코드를 사용하여 안테나 내장형 유도 결합 플라즈마 시스템의 가스 유동 특성, 전력 흡수, 전자 온도, 전자 밀도, 화학종의 분포에 대해서 살펴보았다. 복잡한 현실적 3차원 시스템에 대한 안정한 수치해의 도출을 위해서 최적화된 격자생성 전략을 구사하였으며, 이를 이용하여 플라즈마 질화 시스템을 한 예로 전력 흡수, 가스 유동, 전자 온도, 전자 밀도, 화학종의 분포를 분석하였다. 금속 노출형 안테나의 경우 전력 도입부 쪽에 전력 흡수의 불균형이 모델에서 예측되었으며 유전체피복 안테나의 한 예에서 전력 흡수 표피 깊이가 실제 보고된 값인 53 mm와 잘 일치하는 50 mm로 예측되었다. 또한 수소연료 전지 분리판을 위한 고속 질화 공정용 시스템의 모델링에서도 산업용 대량 처리 시스템에 적절한 다중 분리판의 장입 간격을 가스 유동, 활발한 질화종인 질소 원자와 질소 분자 이온의 농도를 근거로 예측하였다.

• 환경영향평가
• /
• 제19권3호
• /
• pp.231-245
• /
• 2010

The the purpose of this study was to analyze of the vegetation structure and phytosociological changes in the area adjacent to GeumJeong Mountain Fortress for fifteen years. The result of this study was as follows; Of the 8 quadrates, site of the North Gate 2 was having a highest in the number of extinct trees, 15 kinds. This is probably due to trampling effect caused by climbers' steps. Site of the West Gate 1 and South gate 1 each had 8 kinds of extinct trees, respectively. The number of newly appeared trees was highest at site of the North Gate 1, (8 kinds) followed by the sites of South gate 1 and South gate 2, respectively (5 kinds). The highest decrease in number of tree species was observed in North Gate 1, therefore, there is a strong relationship between vegetation diversity and the number of users of the available spaces. In order to revitalize the unstable vegetation structure of the Area Adjacent to GeumJeong Mountain Fortress, Robinia pseudo-acacia has to be well maintained in the shrub tree layer, and vines, such as Smilax china, Humulus japonicus, and Pueraria thungergiana, should be removed. To recover natural vegetation, dead leaf layer should be protected, and more shrub trees need to be planted. In the understory and shrub tree layer, multi layer tree planting is highly recommended to recover natural vegetation and increase tree diversity. In order to improve bad soil condition caused by trampling effect of recreational users, special treatments to the soil structure are required, such as mulching and raking soil. Also, depending on its soil damage from users trampling, the areas in the park should be divided into usable areas and user limited areas by the sabbatical year system. To improve the soil acidity due to acidic rain, soil buffering ability should be improved by activating microorganisms in the soil by using lime and organic material.

• 한국항공우주학회지
• /
• 제36권4호
• /
• pp.321-327
• /
• 2008

극초음속으로 비행하는 추진기관이 직면하는 고속 유동 등 제반 현상을 모사하기 위한 지상시험 설비로 충격파 풍동을 설계, 구축한 후 성능 시험을 수행하였다. 개발된 준 일차원 작동 해석를 이용하여 설계점을 파악한 후, 극초음속 시험설비 구축을 위한 개념 설계를 완료하였다. 이어 단위 해석 코드를 이용하여 구체적인 성능 설계 및 각 구성품에 대한 설계를 완료, 구축한 후, 다양한 운용조건에서 성능시험을 수행하였다. 본 논문에서는 이론해석 결과를 바탕으로 이루어진 개념 설계와 준 1차원 다화학종 해석 코드를 이용한 개념설계 검증 및 성능설계 결과 등 극초음속 충격파 풍동 설계방법을 제시하였다.