• Proceedings of the Korea Water Resources Association Conference
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• 2005.05b
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• pp.628-632
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• 2005

본 연구에서는 장기유출모형인 SWAT 모형의 대유역에 대한 적용성을 평가하고자 하였다. 이를 위해 국내 대표적 대유역인 소양강댐 유역을 선정하여 연구를 수행하였다. SWAT 모형의 기본입력자료인 수문기상 자료와 GIS 자료(DEM, 토지이용도/토지피복도, 토양도)의 국내 구축현황을 고려해 볼 때, 대유역에서의 적용성이 검증된다면 나아가 4대강 유역에 대한 SWAT 모형의 적용 또한 가능해지리라 판단되며, 국가 수자원 계획의 중요한 기초자료를 제공할 수 있을 것이다. 또한, SWAT 모형은 분포형 모형의 장점 중의 하나인 사용자가 원하는 지점에서의 수문성분을 모의할 수 있다. 이는 미계측 유역에 대한 수문성분을 평가할 수 있다는 것으로, 유역내 수위관측지점을 기준으로 관측유량과 모의유량을 비교$\cdot$검토하여 그 적절성을 평가하였다.

• Applied Chemistry for Engineering
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• v.19 no.6
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• pp.592-599
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• 2008

Oil sands had not received enough attention due to high production cost. However, as oil price significantly increases, oil sands are receiving more and more interest as unconventional crude oil. The value and applicability of oil sands can be enhanced by upgrading oil sands bitumen to produce synthetic crude oil (SCO). This study analyzed 213 oil sands upgrading patents applied between 1969 and 2006 in US, Canada, Japan, Europe, and Korea. The upgrading technologies could be classified into 9 detailed technologies; hydrocracking, coking, thermal cracking, deasphalting, supercritical technology, bio-technology, hydrotreating, gasification, and others. The number of patents applied for oil sands upgrading increased after 1970, reached a maximum in the early 1980, and slowly increases again in recent years. Korea has a lack of technologies for oil sands. Therefore, the technologies for oil sands production and application, specially, upgrading technologies based on accumulated oil refinery technologies need to be developed to increase self-development ratio of energy resource.

• Korean Journal of Microbiology
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• v.28 no.1
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• pp.71-75
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• 1990

The isolates biodigrading crude oil were examined to characterize thier properties. Isolates which were identified as Acinetobacter lwoffii G1, Klebsiella pneumoniae L25, Pseudomonas maltophilia N246, Xanthomonas campestris M12, and Xanthomonas sp. M28. The optimum concentration of crude oil was 0.15% for the bacterial growth. X. campestris M12, Xanthomonas sp. M28, and K. penumoniae L25 showed the maximal growth at the concentration of 3.5% sodium chloride, indicating that they were derived from sea water. Among the isolates, X. campestris M12, Xanthomonas sp. M28 specially utilized hexadecane and octane, and P. maltophilia N246 utilized octane with optimum concentration of 0.2-0.3% as sole carbon source. The utilization of components of saturate fraction by K. pneumoniae L25 was examined by gas-liquid chromatography. The short-chain saturates are used before the long chain ones although they almost disappear within 8 days of incubation at $30^{\circ}C$.

• Journal of Life Science
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• v.25 no.2
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• pp.174-179
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• 2015

The presence of psychrotrophic bacteria downgrades the quality of dairy products. This study evaluated the effect of lipolytic psychrotrophic bacteria on the chemical properties of Gouda cheese made from raw milk experimentally inoculated with a psychrotrophic bacterium (Acinetobacter genomospecies 10). Raw milk experimentally inoculated with Acinetobacter genomospecies 10 and refrigerated at $4^{\circ}C$ for 3 or 6 days produced a 6-week ripened Gouda cheese with a significant decrease in total solids (p<0.05) or an increased fat content (p<0.05), respectively. Raw milk inoculated with Acinetobacter genomospecies 10 and refrigerated for 3 days had higher (p<0.05) SCFFA (1.35 times), MCFFA (1.42 times), and LCFFA (1.44 times) than the control 6-week ripened Gouda cheese. The cheese manufactured from the inoculated and refrigerated raw milk had higher (p<0.05) total free fatty acids (1.68 times) compared with the control. Raw milk inoculated with Acinetobacter genomospecies 10 and refrigerated for 6 days had increased SCFFA (1.45 times), MCFFA (1.28 times), and LCFFA (1.38 times) compared with the control 6-weeks ripened Gouda cheese. The 6-week ripened Gouda cheese manufactured from this inoculated milk had higher (p<0.05) total free fatty acids (1.34 times) compared with the control. The results indicated that the production of excessive free fatty acids in dairy products by psychrotrophic bacteria can be critical in predisposing dairy products to off-flavors and in turn degrading their quality.

• Food Science and Preservation
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• v.19 no.1
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• pp.95-103
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• 2012

The objective of this study was to develop models for the predict of the milk properties (fat, protein, SNF, lactose, MUN) of unhomogenized milk using the visible and near-infrared (NIR) spectroscopic technique. A total of 180 milk samples were collected from dairy farms. To determine optimal measurement temperature, the temperatures of the milk samples were kept at three levels ($5^{\circ}C$, $20^{\circ}C$, and $40^{\circ}C$). A spectrophotometer was used to measure the reflectance spectra of the milk samples. Multilinear-regression (MLR) models with stepwise method were developed for the selection of the optimal wavelength. The preprocessing methods were used to minimize the spectroscopic noise, and the partial-least-square (PLS) models were developed to prediction of the milk properties of the unhomogenized milk. The PLS results showed that there was a good correlation between the predicted and measured milk properties of the samples at $40^{\circ}C$ and at 400~2,500 nm. The optimal-wavelength range of fat and protein were 1,600~1,800 nm, and normalization improved the prediction performance. The SNF and lactose were optimized at 1,600~1,900 nm, and the MUN at 600~800 nm. The best preprocessing method for SNF, lactose, and MUN turned out to be smoothing, MSC, and second derivative. The Correlation coefficients between the predicted and measured fat, protein, SNF, lactose, and MUN were 0.98, 0.90, 0.82, 0.75, and 0.61, respectively. The study results indicate that the models can be used to assess milk quality.

• Korean Journal of Organic Agriculture
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• v.27 no.2
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• pp.147-160
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• 2019

This study was conducted to evaluate roughage to concentrate ratio on the changes of productivity and metabolic profiling in milk. Six lactating Holstein cows were divided into two groups, T1 group was fed low-concentrate diet (Italian ryegrass to concentrate ratio = 8:2) and T2 group was fed high-concentrate diet (Italian ryegrass to concentrate ratio = 2:8). Milk samples were collected and its components and metabolites were analyzed by ¹H-NMR (Nuclear magnetic resonance). The result of milk components such as milk fat, milk protein, solids-not-fat, lactose and somatic cell count were not significantly different between two groups. In carbohydrate metabolites, trehalose and xylose were significantly higher (P<0.05) in T1 group, however lactose was not significantly different between two groups. In amino acid metabolites, glycine was the highest concentration however, there was no significant difference observed between two groups. Urea and methionine were significantly higher (P<0.05) in the T2 group. In lipid metabolites, carnitine, choline and O-acetylcarnitine there were no significant difference observed between the two groups. In benzoic acid metabolites, tartrate was significantly higher (P<0.05) in T2 group. In organic acid metabolites, acetate was significantly higher (P<0.05) in T1 group and fumarate was significantly higher (P<0.05) in T2 group. In the other metabolites, 3-methylxanthine was only significantly higher (P<0.05) in T2 group and riboflavin was only significantly higher (P<0.05) in T1 group. As a result, milk components were not significantly different between two groups. However, metabolites concentration in the milk was significantly different depends on roughage to concentrate ratio.

• Proceedings of the Korea Water Resources Association Conference
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• 2005.05b
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• pp.65-69
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• 2005

SWAT 모형은 우리나라 논 지역에서의 수리관행을 이행할 수 있도록 관개용수의 공급과 담수지역에 대한 성분해석에 대한 기본적인 틀을 갖추고 있으며, 각종 물관리 체계의 조작이 가능한 우수한 모형이다. 그러나, 실제 우리나라 농업지역에 관개용수를 공급하고 담수상태의 논 지역을 충분히 모사하지 못하고 있다. 따라서, 이러한 결함을 제거하기 위해서는 SWAT 모형의 관개용수공급과 관련한 내부 모듈의 전면적인 수정$\cdot$보완과 교체작업이 필요하였다. 이러한 SWAT 모형의 문제점 해결을 위해 우리나라 는 농사의 특징인 담수를 고려하고, 관개량 및 관개일정을 제어하여 담수 논에 대한 수문성분이 전체 하천유출을 포함하는 수문순환 과정에 미치는 영향을 정량적으로 평가할 수 있는 SWAT-AGRIMAN(SWAT-AGRIculture MANagement) 모형을 개발하였다. 개발된 SWAT-AGRIMAN 모형을 보청천 기대교 상류유역에 적용하였고, 적용결과를 SWAT 모형에 의한 모의결과와 비교$\cdot$평가하였다. 관개용수의 수원의 제기능 여부 및 담수상태의 유지여부와 논의 침투량 및 증발산량, 유역 출구에서의 유출량의 변화특성을 살펴보았으며, 실제 관측유량과의 유출율, 평균제곱근오차(RMSE), 모형효율계수(ME), 상관계수(CORRL), 결정계수($R^2$)의 비교$\cdot$분석을 통해 모형을 평가하였다.

• Proceedings of the Korea Water Resources Association Conference
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• 2008.05a
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• pp.1244-1248
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• 2008

지표수-지하수 통합모형인 SWAT-MODLFOW는 토양수가 침루과정을 거쳐 지하수로 유입되는 일방향 구조를 갖고 있어 지하수위 상승 및 하강에 따른 토양수량, 침루량, 중간유출량 등 수문성분량의 변화를 고려할 수 없다. 따라서 본 연구에서는 지하수위 변화에 따른 토양수의 분포양상 변화를 고려할 수 있도록 토양수-지하수간의 연결 구조를 양방향으로 개선하여 두 영역간의 연결성을 강화하였다. 지하수위가 상승할 경우 토양대와 지하수대간의 중첩 영역이 생기게 되는데, 이 중첩 영역을 지하수대로 간주하여 영역 내 흐름거동이 지하수 유동 메커니즘을 따르는 토양수-지하수 결합루틴을 새롭게 제시하였다. 이 결합루틴은 지하수 상승, 하강에 따라 토양수대의 두께가 변하는 가변 토양층 방식(variable soil layer method)으로 계산을 수행할 수 있도록 코드를 구성하였다. 개선된 SWAT-MODLFOW 모형을 무심천 유역에 적용하여 토양수와 지하수간의 상호작용을 해석하고 하천저지대와 같이 지하수위 상승지역에서의 수문성분량의 분포를 보다 현실적으로 구현할 수 있음을 입증하였다.

• 한국해양학회지
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• v.20 no.1
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• pp.74-82
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• 1985

Exposed on the sea, the oils are affected by the combined effects of evaporation, solution, chemical oxidation, and biological decomposition. Therefore the samples were taken after artificial weathering, and they were analyzed by gas chromatography for sulfur and hydrocarbons. The measurement results of gas chromatography have shown characteristic patterns. The peaks of the lower hydrocarbons in pollutant oil decreased with time. But the chromatograms for sulfur compound analysed by FPD showed little changes with lapse of time. The hydrocarbon and sulfur compound analysis by gas chromatography can be effectively used for analyzing oils for comparative identification.

• Journal of Aquaculture
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• v.12 no.2
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• pp.115-122
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• 1999

Exposure experiments during the egg development were conducted to assess the influences of 5 different concentrations (0, 25, 50, 75 and 100%) of water-soluble fraction (WSF) of Kuwait crude oil on the eggs and larvae of black seabream (Acanthopagrus schlegeli), red seabream (Pagrus major) and olive flounder (Paralichthys olivaceus). All experiments were triplicated. Hatching time and hatching rate were examined on the eggs. The median lethal time ($LT_{50}$), morphological abnormality and swimming activity (swimming frequency and speed) of larvae were also investigated. The time and rate of egg hatching were not significantly influenced by WSF on the eggs of the fishes. The larvae exposed to WSF during the egg development were also not significantly influenced on the $LT_{50}$ and swimming activity. But the higher morphological abnormalities of notochord were observed from the larvae in 100% WSF exposure.