• 한국환경과학회지
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• 제32권5호
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• pp.303-313
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• 2023

In this study, the hydraulic gradient was calculated using the groundwater level and rainfall observed in the Hyogyo-ri area for a year, and the change in the hydraulic gradient according to the rainfall was analyzed. It was found that the groundwater level increased as the rainfall increased in all groundwater wells in the research site, and the groundwater level rise decreased as the altitude of the groundwater well increased. The hydraulic gradient in the research site ranged from 0.016 to 0.048, decreasing during rainfall and increasing after the end of the rainfall. As the rainfall increased, the groundwater level rise in the low-altitude area was more than the high-altitude area, and the hydraulic gradient decreased due to the difference in groundwater level rise according to the altitude. Through this study, it was found that the influence of rainfall is dominant for the fluctuation of the hydraulic gradient in the unconfined aquifer.

• 한국미생물·생명공학회지
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• 제33권3호
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• pp.226-230
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• 2005

The microbial community during composting of gargage was analyzed using 16S rDNA PCR - DGCE (denaturing gradient gel electrophoresis). Pseudomonas spp. was found throughout the process, and thermophilic Bacillus spp. was dominated at the thermophilic stage. Six thermophilic bacteria were isolated and identified as B. caldoxylolyticus, B. thermoalkalophilus, and B. thermodenitrificans.

• Journal of Ecology and Environment
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• 제42권4호
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• pp.278-284
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• 2018

Plant functional traits have been shown to be useful to understand how and why ecosystems and their components vary across environmental heterogeneity or gradients. This study investigated how plant functional (leaf) traits vary according to an elevation-associated environmental gradient. Environmental gradients (mean annual temperature and precipitation) were quantified, and leaf traits (leaf area, specific leaf area, leaf nitrogen, leaf phosphorus, leaf carbon, and leaf C/N ratio) of the understory woody plant species Acer pseudosieboldianum were examined across an elevational gradient ranging from 600 to 1200 m in a Baegunsan Mountain in Gwangyang-si, Jeollanam-do, South Korea. The results showed that mean annual temperature and precipitation decreased and increased along with elevation, respectively. Leaf area of the plant species decreased slightly with increasing elevation, while specific leaf area did not differ significantly. Leaf nutrients (nitrogen, phosphorus, and carbon concentrations) were higher at high elevations, but leaf C/N ratio decreased with elevation.

• 한국수자원학회논문집
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• 제56권10호
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• pp.691-695
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• 2023

본 연구에서는 효교리 지역에서 지형 경사가 다른 2개 구간을 설정하여 구간별 수리경사를 산정하고 지형 경사와 강우에 따른 수리경사 변동을 분석하였다. 연구부지 내 모든 지하수공에서 강우량이 증가할수록 지하수위가 상승하는 것으로 나타났으며, 지하수위 상승량은 지하수공의 고도가 높을수록 작았다. 연구부지 내 수리경사의 변동은 지형 경사가 급한 구간에서는 크고 지형 경사가 완만하면 작았다. 강우에 의한 수리경사 변동은 지형 경사가 급한 구간에서는 강우에 의한 영향성이 높았으며, 지형 경사가 완만한 구간에서는 강우에 의한 영향성이 낮았다. 본 연구를 통해 자유면 대수층에서 수리경사 변동은 지형 경사와 강우에 의한 복합적인 영향으로 나타남을 알 수 있었다.

• 한국지반환경공학회 논문집
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• 제13권3호
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• pp.13-19
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• 2012

최근 기상이변에 의해 대형 태풍과 집중 호우가 발생하게 되었고, 이로 인한 이상 홍수로 인해 제방 붕괴를 일으켜 인근지역에 직접적인 큰 재산피해와 인명피해를 가져오게 되는 일이 적지 않다. 본 논문에서는 하천제방 단면의 주요 특성치인 제방 둑마루 폭, 비탈면 경사도, 제방 높이의 변화에 따른 수치해석을 실시하였고, 유출부 동수경사를 분석하여 제방에 대한 안정성 검토를 실시하였다. 그 결과 비탈면 경사의 확대가 둑 마루폭 증가보다 유출부 영역에서의 동수경사 감소 효과를 더 크게 나타나는 것으로 평가되었다. 즉, 하천 제방 설계 및 보강 시 비탈면 경사의 확대가 둑 마루폭 증가보다 더 효과적인 것으로 판단된다.

• The Korean Journal of Ecology
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• 제9권4호
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• pp.225-230
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• 1986

The environmental gradient analyses and the continum analyses were applied for the ordinationa of forest vegetation in Seonunsan area. In the soil moisture gradient, mesic to xeric, Zelkova serrata, Carpinus tschonoskii, Quercus aliena, Carpinus laxiflora, Quercus serrata, Quercus variabilis and Pinus densiflora type were arranged as a series of sequence along the gradient. In two dimensional analyses of soil moisture and organic matter gradients seven vegetation types mentioned above were also separated one another. Especially Carpinus tschonoskii in mesic-fertile sites adn Pinus densiflora in xeric-sterile were noticeable. The results of continum analyses were corresponded to those of environmental gradient analses for the forest vegetation.

• 한국환경성돌연변이발암원학회지
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• 제18권2호
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• pp.83-88
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• 1998

To detect the mutation in a given sequence, there are variety of methods developed by use of the gel electrophoresis. One of the methods, TGGE (Temperature Gradient Gel Electrophoresis), is a popular technique because it can detect mutations in DNA fragment with ease and at low cost. This study used 200 bp BamHI-digested DNA fragment containing the human $\varepsilon$-globin promoter which was mutated[$\varepsilon$ F1*(-141), GATA- I*(-163), and GATA-1* & $\varepsilon$F1]. This BamHI-digested DNA fragment was directly used to detect the mutated DNA fragment on 50% denaturant gel with temperature gradient of 45$^{\circ}C$ through $53^{\circ}C$. In agreement with the theoretical result of MELTSCAN program (Brossette and Wallet, 1994) the mobilities of mutated DNA fragments were shown to be nearly distinguished on the temperature gradient gel. In contrast to the above result the heteroduplex analysis under the temperature gradient condition was shown to detect the mutated DNA fragments through the heteroduplex formation between strands of mutated DNA and wild-type DNA.

• 자원환경지질
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• 제32권5호
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• pp.503-517
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• 1999

The purpose of this study is to verfify a more effecive techique for calculating geothermal gradient. this study examines 370 data of temperature-logging having been collected since 1985. The daya are divided into three different grades grades according to the type of temperature-depth plots: 204 data show typical linear gradient (Grade A); 126 data do not explicitily show the gradient becase of various external effects such as water flow (Grade B); and the rest 40 data do not show the gradient at all (Grade D). The new technique for calculating geothermal gradient is to be required to use Greade-B data more effctiviely. This new technique includes (1) calculating the independer depth of atmospheric temperature in the earth; (2) drawing a distribution map of subsurface tempurature by using the distribution map of subsurface temperature by using Grade-A data at the independent depth; and (3) recalculating geothermal gradient of Grade-B data by using the distrbution map of subsurface temperature, borehole depth, and bottom temperature of Grade-B data by using the distribution map of subsurface temperature, borehole depth, and bottom temperature of Grade-B data. As a result, 330 data-both Grade-A and Grade-B data--can be used to draw a distribution map of hot spradient. The map clearly distinguishes anomaly areas, and helps interpret their relations to the distribution of hot springs, geology, geological structures, and geophysical anomaly areas. These new results reveal that the average of geothermal in south Korea is 25.6$^{\circ}C$/km, when calculated to the Kriging method.

• 상하수도학회지
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• 제35권6호
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• pp.507-516
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• 2021

In this study, the machine learning which has been widely used in prediction algorithms recently was used. the research point was the CD(chudong) point which was a representative point of Daecheong Lake. Chlorophyll-a(Chl-a) concentration was used as a target variable for algae prediction. to predict the Chl-a concentration, a data set of water quality and quantity factors was consisted. we performed algorithms about random forest and gradient boosting with Python. to perform the algorithms, at first the correlation analysis between Chl-a and water quality and quantity data was studied. we extracted ten factors of high importance for water quality and quantity data. as a result of the algorithm performance index, the gradient boosting showed that RMSE was 2.72 mg/m³ and MSE was 7.40 mg/m³ and R² was 0.66. as a result of the residual analysis, the analysis result of gradient boosting was excellent. as a result of the algorithm execution, the gradient boosting algorithm was excellent. the gradient boosting algorithm was also excellent with 2.44 mg/m³ of RMSE in the machine learning hyperparameter adjustment result.

• 한국전산유체공학회지
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• 제21권2호
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• pp.32-39
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• 2016

The Gradient Biome is a unique and large greenhouse(length 200 m, width 50 m, height:40 m) in which the elements of the weather, such as temperature and humidity, are controlled and reproduced in such a way as to create a continuous gradient from the tropical to frigid zones along specified longitudinal or transvers lines on the earth. One of the main purposes of the Gradient Biome is to observe the possible responses of the ecosystems (mainly plants), which are to be corresponding to each test climate and be introduced in the Biome, to the expected global warming. As one of the expected responses is the shift of the ecosystem(s) toward the region of suitable environment, there should be no artificial obstacles, which can prevent the shift, inside the facility. However, it is important but not so easy to find the ways of how the temperature and humidity in the Biome could be reproduced since the environmental variables tends to be homogeneous. In this paper, numerical simulations were carried out to find the effective control methods for air temperature and humidity inside the real scale Biome. One of the contributed solvers of OpenFOAM, which is an open source physics simulation code, was modified and used for the simulations.