• Korean Journal of Food Science and Technology
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• v.53 no.1
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• pp.55-62
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• 2021

This study was conducted to investigate the potential of sea buckthorn leaf (SBL) as a natural antioxidant. SBL was extracted using different ethanol ratios (0, 40, 80, and 100%), and the resulting extracts were examined for their antioxidant contents and antioxidant activities using various methods. The 40% and 80% ethanol extracts (EEs) showed higher total polyphenol contents of 285.06 and 285.64 mg GAE/g respectively, than those in other solvents, and as the ethanol concentration increased, other antioxidant contents of the extracts increased. The 40% and 80% EEs recorded the highest radical scavenging activities against DPPH, superoxide-, ABTS+, nitrite scavenging activity (NO-), and reducing power (RP). The NO- and RP of the SBL EEs were higher than those of ascorbic acid or tannin, which are known as representative antioxidants. The results of this study, suggest that SBL is a potential source of natural antioxidants.

• Journal of the Korean Institute of Intelligent Systems
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• v.16 no.6
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• pp.777-784
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• 2006

This paper proposes a c-fuzzy model tree using partial least square method to predict the Chlorophyll-a concentration in each zone. First, cluster centers are calculated by fuzzy clustering method using all input and output attributes. And then, each internal node is produced according to fuzzy membership values between centers and input attributes. Linear models are constructed by partial least square method considering input-output pairs remained in each internal node. The expansion of internal node is determined by comparing errors calculated in parent node with ones in child node, respectively. On the other hands, prediction is performed with a linear model haying the highest fuzzy membership value between input attributes and cluster centers in leaf nodes. To show the effectiveness of the proposed method, we have applied our method to water quality data set measured at several stations. Under various experiments, our proposed method shows better performance than conventional least square based model tree method.

• Proceedings of the Korean Environmental Sciences Society Conference
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• 2016.10a
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• pp.294-294
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• 2016

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 2000.10a
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• pp.171-172
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• 2000

본 연구에서는 ocean color 위성자료의 검ㆍ보정 및 수산활용을 목적으로 6개 OSMI위성 밴드와 동일한 현장 해수 다중 채널 광 측정기, PRR-800 관측자료 및 SeaWiFS 위성 자료, 해양현장의 클로로필 a, 부유성 고형물질 등의 관측자료간 관계식을 도출하고 한국 근해에서 해수의 광학적 특성을 구명하고자 하였다. (중략)

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 2000.05a
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• pp.223-224
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• 2000

해양수색 위성자료 실용화 기법을 개발하기 위해서는 동시·공간적인 위성자료와 현장조사자료의 비교 검토가 필요하다. 따라서 SeaWiFS위성이 한국 근해를 통과할 시 투명도와 해수색 환경의 변화요인이 되는 기초먹이생물량(클로로필 a)을 관측하고 분석하여 그 분포특성을 밝히고자 하였다. (중략)

• Journal of Environmental Science International
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• v.5 no.2
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• pp.153-170
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• 1996

Photosynthetic pigments and their degradation products in suspended and sinking particles collected from the Gulf of Mexico waters 1987~88, were measured using High Performance liquid Chromatography (HPIC). The short term variations in flux rates of chlorophylls and carotenoids as well as-their degradation products were compared at the mesoscale cyclonic and anticyclonic circulation features (cold joie rink and warm core ring). Chlorophyll a was the predominant porphyrin of suspended particulate matter at both CCR -and WCR. Among carotenoid pigments, 19'-hexanoyloxyfucoxanthin, which is a biomarker of prymnesiophytes, was dominant pigment at both rinds. Phaeophorbide a, which is produced through the Brazing processes of grazers, was the predominant degraded pigment in sinking particles ai the study aiea. Total pigment flux in CCR was an order of magnitude higher than that in WCR. Less than l% of the standing stock of the pigments measured sank out of the upper 200m of the WCR on any given day. Thus, suspended particulate matter in Gulf of Medico was not recycled rapidly.

• Journal of Environmental Impact Assessment
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• v.19 no.4
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• pp.367-380
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• 2010

수산 해양환경적 측면에서 중요한 위치에 있는 황해(Yellow Sea)의 해양 생태계 변화과정에 대 한 체계적이고 심층적인 연구을 위하여 기후 변화와 관련된 생태 및 환경변화에 대한 황해 해역의 반응성 연구가 필요한 실정이다. 본 연구는 황해해역에서 수온 상승에 따른 클로로필의 변화를 살펴보고, 지구온난화가 해양환경과 생태계에 미칠 영향을 예측하고자 하였다. 황해해역에서 해수유동 모델의 결과를 기초 입력자료로 활용하여 클로로필과 상호작용을 하는 육상유입부하량, 저질 영양 염용출량 및 생물학적 파라메타 등을 입력하여 현재상태를 재현하였다. 우리나라 주변 해수의 온도가 지난 10년간 약 $0.75^{\circ}C$ 상승했다고 가정하였을 때, 본 실험에서는 수온이 선형적으로 연간 $0.075^{\circ}C$ 씩 상승한다고 가정하여 10년 후까지의 Chlorophyll-a 농도 변화를 예측하였다. 예측 결과, 연구해역의 중앙부에서는 전체적으로 농도가 높아지고, 우리나라 연안해역에서 Chlorophyll-a 의 농도가 낮아지는 것으로 예측되었다. 본 연구의 결과를 기초로 하여 10년 이상의 장기적인 예측실험을 한다면 기후변화가 황해해역의 생태계 변화에 미치는 영향을 파악할 수 있을 것으로 기대된다.

• Journal of Environmental Impact Assessment
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• v.32 no.6
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• pp.419-430
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• 2023

In response to the periodic occurrence of cyanobacterial blooms in Korean freshwaters, various types of cyanobacteria removal technologies are being developed and implemented. Due to the differing principles behind these technologies, it is difficult to compare and evaluate their removal efficiencies. In this study, a standardized method for evaluating cyanobacteria removal efficiency was proposed by utilizing the results of removal operations using a mobile cyanobacteria removal device in the Seohwacheon area of Daechung Reservoir. During removal operations, the decrease in chlorophyll-a (chl-a) concentration (ΔChl-a) in the working area was calculated based on the amount of collected sludge, the efficiency rate, and the concentration of chl-a. Additionally, the required working days (WD) to reduce the chl-a concentration to 1 mg/m³ in the target area was calculated based on the area of the target zone, the maximum daily working area, and the efficiency rate. A method for calculating the cyanobacteria removal capacity was proposed based on the reduction rate of chl-a concentration in the water before and after the operation, the treatment capacity of the removal technology, and the water volume of the target area. The cyanobacteria removal capacity of the mobile cyanobacteria removal device used in this study was 6.64%/day (targeting the Seohwacheon area of Daechung Reservoir, approximately 500,000 m²), which was higher compared to other physical or physicochemical cyanobacteria removal technologies (0.02~4.72%/day). Utilizing the evaluation method of cyanobacteria removal efficiency presented in this study, it will be possible to compare and evaluate the cyanobacteria removal technologies currently being applied in Korea. This method could also be used to assess the performance and efficiency of physical or physicochemical combined cyanobacteria removal techniques in the "Guidelines for the Installation and Operation of Algae Removal Facilities and the Use of Algae Removal Agents" operated by the National Institute of Environmental Research.

• 한국해양학회지
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• v.20 no.3
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• pp.30-36
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• 1985

Water quality of seawater samples from ten stations was measured and analyzed to study the causes and the characteristics of the yellowish-green-colored zone in the Nakdong Estuary in February, May, August and October, 1984. The color of the yellowish-green-colored zone was equivalent to the grade 7 according to the Forel water-color meter and was observable throughout the year. The characteristics of the zone were low in transparency and high in the concentration of suspended solids, and about 52% of the suspended solids consisted of volatile substances. The chlorophyll a contents ranged from 0.4mg/$m^3$ to 51.0mg/$m^3$ and dissolved oxygen was in a state of supersaturation within the yellowish-green-colored zone. Nutrient concentrations were higher within the colored zone than the outside. Positive correlation was observed between tne concentrations of nutrients and chlorophyll a. Our results showed that the signficant portion of suspended solids sampled from the yellowish-green-colored zone consisted of phytoplanktons of which bloom was possibly induced by inflow of the nutrient-rich Nakdong River water.

• Korean journal of food and cookery science
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• v.30 no.3
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• pp.340-350
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• 2014

The physicochemical and sensory properties of bean sprouts with different namulkong cultivars were examined. The five namulkong cultivars included were as follows : Nokchaekong, Dawonkong, Seonamkong, Orialtae, and Pungsannamulkong with light green, black, yellow, dark green, and yellow seed coats, respectively. The bean sprouts were cultivated in a lab and were used for analyses. The instrumental textural hardness and lipoxygenase activity of the heads were higher than those of the stems in both fresh and boiled bean sprouts. The 3 minutes of boiling caused a decrease in the hardness and lipoxygenase activity of the heads and the stems. The chlorophyll a and b contents in the heads were higher than those in the stems, and they decreased with boiling. The fresh bean sprouts with Dawonkong, Seonamkong and Pungsannamulkong showed higher acceptability than those with Nokchaekong and Orialtae. The higher acceptability was observed in the boiled and flavored bean sprouts with Seonamkong and Pungsannamulkong.