• 한국농공학회지
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• 제32권E호
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• pp.1-19
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• 1990

Abstract Over the last several decades, crop production in the United States increased largely due to the extensive use of animal waste and fertilizers as plant nutrient supplements, and pesticides for crops pests and weed control. Without the application of animal waste best management, the use of animal waste can result in nonpoint source pollution from agricultural land area. In order to increase nutrient levels and decrease contamination from agricultural lands, nonpoint source pollution is responsible for water quality degradation. Nonpoint source pollutants such as animal waste, ferilizers, and pesticides are transported primarily through runoff from agricultural areas. Nutrients, primarily nitrogen and phosphorus, can be a major water quality problem because they cause eutrophic algae growth. In 1985, it was presented that Watershed/Water Quality Monitoring for Evaluation BMP Effectiveness was implemented for Nomini Creek Watershed, located in Westmoreland County, Virginia. The watershed is predominantly agricultural and has an aerial extent of 1505 ha of land, with 43% under cropland, 54% under woodland, and 3% as homestead and roads. Rainfall data was collected at the watershed from raingages located at sites PNI through PN 7. Streams at stations QN I and QN2 were being measured with V-notch weirs. Water levels at the stream was measured using an FW-l Belfort (Friez FWl). The water quality monitoring system was designed to provide comprehensive assessment of the quality of storm runoff and baseflow as influenced by changes in landuse, agronomic, and cultural practices ill the watershed. As this study was concerned with the Nomini Creek Watershed, the separation of storm runoff and baseflow measured at QNI and QN2 was given by the master depletion curve method, and the loadings of baseflow and storm runoff for TN (Total Nitrogen) and TP (Total Phosphorus) were analyzed from 1987 through 1989. The results were studied for the best management practices to reduce contamination and loss of nutrients, (e.g., total nitrogen and total phosphorus) by nonpoint source pollution from agricultural lands.

• Environmental Engineering Research
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• 제25권2호
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• pp.230-237
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• 2020

Nitrogen flux release from organically enriched sediments into overlying water, which may have significantly influence on water quality and increasing continuous eutrophication. The purpose of this study is to evaluate the remediation efficiency of oyster shell powder and its treated product into organically enriched sediment in terms of nitrogen flux, organic matter, chlorophyll-a, pH and dissolved oxygen (DO). The TOSP was mainly composed of CaO2. The application of TOSP into the sediment has increased the pH, DO and significantly decreased the concentrations of NH₄⁺-N and T-N compared to other basins. On the other hand, nitrate was enriched with the addition of treated oyster powder, an oxygen releasing compound on both phases. Furthermore, chlorophyll-a was found to be increasing with time in the control basin meanwhile it dropped drastically with the addition of TOSP, which implied on the repression of algal growth owing to blockage of nitrogen source migrating from the sediment. This study has shown that the TOSP was effective to improve sediment-water quality, diminish eutrophication and control harmful algae blooms in a marine environment. Therefore, it is a good reference as an effective environmental remediation agent.

• 한국산학기술학회:학술대회논문집
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• 한국산학기술학회 2012년도 춘계학술논문집 1부
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• pp.278-281
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• 2012

본 연구는 고주파를 발생시키는 고주파기기를 이용한 조류배양시스템에 관한 것으로, 미세조류 배양시 고주파 파형을 이용하는 것이다. 미세조류 배양을 위한 생물반응기에 200KHz~400KHz 고주파 파형이 나오도록 설계되었으며, Osillograph상에서 impedence가 최소가 되는 특정 지점에서 공명을 일으킬 때, 전기적 저항은 최소가 되며, 이상적인 고주파 파형 발생으로 생물반응기내의 미세조류의 Survival과 Growth에 직접적인 영향을 미치는 것을 확인하였다. 본 연구의 고주파 파형을 이용한 조류배양 시스템 개발은 자외선 흡수능을 높이는 조류배양에 활용될 수 있을 뿐만 아니라, 미세조류세포 내의 다양한 신호전달에 관련된 특정 피토케미칼, 펩타이드, 단백질 대사 연구에 유용하게 활용될 수 있다.

• Journal of Advanced Marine Engineering and Technology
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• 제29권6호
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• pp.654-661
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• 2005

Copper is a well known alloying element that is used to improve the resistance to general corrosion of stainless steel And also Cu cation have the anti-fouling effect to inhibit adhesion of the marine algae and shellfish to the surface of heat exchanger cooling pipe or outside wall of the ship, Therefore there are some anti-fouling methods such as anti-fouling Paint mixed with copper oxide or MGPS(Marine Growth Preventing System) by using Cu cation dissolved to the sea wather solution. Cu cation can be dissolved spontaneously by galvanic current due to Potential difference between Cu and cooling pipe of heat exchanger with Ti material, which may be one of the anti-fouling designs. In this study the effect of annealing heat treatment to galvanic current and Polarization behavior was investigated with a electrochemical points of view such as measurement of corrosion Potential, anodic polarization curve. cyclic voltammetric curve, galvanic current etc The grain size of the surface in annealed at $700^{\circ}C$ was the smallest than that of other annealing temperatures. and also the corrosion Potential showed more positive potential than other annealing temperatures. The galvanic current between Ti and Cu with annealed at $700^{\circ}C$ was the largest value in the case of static condition. However its value in the case of flow condition was the smallest than the other temperatures. Therefore in order to increase anti-fouling effect by Cu cation, the optimum annealing temperature in static condition of sea water is $700^{\circ}C$, however non- heat treated specimen in the case of flow condition may be desirable.

• 한국정밀공학회지
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• 제30권2호
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• pp.137-142
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• 2013

The indiscriminate use of the fossil fuel has caused serious environmental pollutions such as the shortage of energy and global warming. Microalgae have being emphasized as $3^{rd}$ generation biomass which makes the carbon dioxide reduce effectively as well as produces the biofuel. Large scale production of microbial biomass by continuous culture is a quite challenging issue, because off-line optimization strategies of a microbial process utilizing a model-based scheme give rise to many difficult problems. In this paper, the static and simple control method which was able to be applied in time-variant growth environment and large scale of algae culture was studied. The significant disturbances in on-line measurement of cell density were reduced by Savitzky-Golay FIR smoothing filter. Dunaliella salina was cultivated continuously in a flat panel photobioreactor by the on-off control of the turbidostat process.

• 한국축산식품학회지
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• 제23권1호
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• pp.80-85
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• 2003

티벳산 발효유로부터 분리한 Candida kefyr TFP7의 항균활성 및 항암활성을 검토하기 위하여 PDA배지를 이용한 십진 희석법에 의해 10균주(TFP1∼10)를 분리하여 몇 종의 병원균과 식중독균, 식품과 관련이 있는 세균, 효모, 곰팡이, 녹조류 및 토양으로부터 분리한 방선균 등 18균주에 대하여 항균활성을 조사하였으며, 또한, 9종류의 인체 암세포주에 대하여 항암활성을 비교하였다. 항균활성 검사에서는 Gram 양성균 중 iwicrococcus iuteus ATCC l1880에 대하여 분리균주 (TFP2∼10)와 방선균인 Styeptomyces murinus JCM 4333에 패하여 분리균주(TFP6∼10)가 뚜렷한 생육억제효과를 나타내었다. 한편, 항암활성 검사에서는 SNU-5(human stomach carcinoma), SW-534(human larynx carcinoma)에 대하여 분리 균주(TFP1∼10) 모두 각각 60%, 70%이상의 생육억제 효과를 나타내었다. 특히, 균주 TFP7은 SNU-5, SW-534에 대하여 각각 77.5%, 76.5%의 가장 우수한 생육억제 효과를 나타내었다.

• Advances in Energy Research
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• 제2권1호
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• pp.1-9
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• 2014

The green microalgae Chlamydomonas reinhardtti is well-known specie in the terms of $H_2$ production by photo fermentation and has been studying for a long time. Although the $H_2$ production yield is promising; there are some bottlenecks to enhance the yield and efficiency to focus on a well-designed, sustainable production and also scaling up for further studies. D1 protein of photosystem II (PSII) plays an important role in photosystem damage repair and related to $H_2$ production. Because Chlamydomonas is the model algae and the genetic basis is well-studied; metabolic engineering tools are intended to use for enhanced production. Mutations are focused on D1 protein which aims long-lasting hydrogen production by blocking the PSII repair system thus $O_2$ sensitive hydrogenases catalysis hydrogen production for a longer period of time under anaerobic and sulfur deprived conditions. Chlamydomonas CC124 as control strain and D1 mutant strains(D240, D239-40 and D240-41)are cultured photomixotrophically at $80{\mu}mol\;photons\;m^{-2}s^{-1}$, by two sides. Cells are grown in TAP medium as aerobic stage for culture growth; in logarithmic phase cells are transferred from aerobic to an anaerobic and sulfur deprived TAP- S medium and 12 mg/L initial chlorophyll content for $H_2$ production which is monitored by the water columns and later detected by Gas Chromatography. Total produced hydrogen was $82{\pm}10$, $180{\pm}20$, $196{\pm}20$, $290{\pm}30mL$ for CC124, D240, D239-40, D240-41, respectively. $H_2$ production rates for mutant strains was $1.3{\pm}0.5mL/L.h$ meanwhile CC124 showed 2-3 fold lower rate as $0.57{\pm}0.2mL/L.h$. Hydrogen production period was $5{\pm}2days$ for CC124 and mutants showed a longer production time for $9{\pm}2days$. It is seen from the results that $H_2$ productions for mutant strains have a significant effect in terms of productivity, yield and production time.

• 생태와환경
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• 제34권4호통권96호
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• pp.285-291
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• 2001

상위포식자에 의해 유도되는 Scenedesmus dimorphus (T$\ddot{u}$rpin) K$\ddot{u}$tzing의 군체형성에 관한 실험을 수행하였다. 동물플랑크톤 Daphnia magna (300 ind./L)와 Moina macrocopa (500 ind./L) 배양한후, $0.1\;{\mu}m$ (millipore)로 여과하여 얻어낸 용액 (ZFW)을 S. dimorphus가 1.8 ($10^5\;cells/ml$까지 자란 처리군에 첨가하여, ZFW를 넣지않은 대조군과 비교하였다. 대조군에 비해 두 동물플랑크톤 처리군에서 S. dimorphus의 군체형성의 유도가 뚜렷이 관찰되었다. 이 현상은 M. macrocopa 보다는 D. magna처리군에서 뚜렷하게 관찰되었으며, 첨가해준 ZFW의 양이 증가할수록 particle당 세포수도 비례적으로 증가하는 것으로 나타났다. ZFW처리군에서 1군체당 세포수(cells/colony)와 평균체적 (mean particle biovolume)은 $24{\sim}72$시간 사이에 급격히 증가하는 것으로 관찰되었다. S. dimorphus의 군체형성현상은 동물플랑크톤 D. magna와 M. macrocopa의 분비물에서 유도되는 화학물질의 영향으로 보이며, 이와 같은 형태변화현상은 동물플랑크톤의 포식에 대한 방어기작으로 작용하게 될 것으로 사료된다.

• Ocean and Polar Research
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• 제25권4호
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• pp.625-631
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• 2003

While phytoplankton diversity and productivity in the Southern Ocean has been widely studied in recent years, most attention has been given to elucidating environmental factors that affect the dynamics of micro-plankton (mainly diatoms) and nano-plankton (mainly Phaeocystis antarctica). Only limited effects have been given to studying the occurrence and the potential risks associated with the blooming of dinoflagellates in the relevant waters. This study focused on the appearance and toxicological characteristics of a toxic dinoflagellate, Alexandrium tamarense, identified and isolated from the Drake Passage in a research cruise from November to December 2001 The appearance of A. tamarense in the Southern Ocean indicates the risk of a paralytic shellfish poisoning (PSP) outbreak there and is therefore of scientific concern. Results showed that while the overall quantity of A. tamarense in water samples from 30meters below the sea surface often comprised less than 0.1% of the total population of phytoplankton, the highest concentration of A. tamarense (20 cells $L^{-1}$) was recorded in the portion of the Southern Ocean between the southern end of South America and the Falkland Islands. Waters near the Polar Front contained the second highest concentrations of 10-15 cells $L^{-1}$. A. tamarense was however rarely found in waters near the southern side of the Polar Front, indicating that cold sea temperatures near the Antarctic ice does not favor the growth of this dinoflagellate. One strain of A. tamarense from this cruise was isolated and cultured for further study in the laboratory. Experiments showed that this strain of A. tamarense has a high tolerance to temperature variations and could survive at temperatures ranging from $5-26^{\circ}C$. This shows the cosmopolitan nature off. tamarense. With regard to the algal toxins produced, this strain of A. tamarense produced mainly C-2 toxins but very little saxitoxin and gonyailtoxin. The toxicological property of this A. tamarense strain coincided with a massive death of penguins in the Falkland Islands in December 2002 to January 2003.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2002년도 생물공학의 동향 (X)
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• pp.112-115
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• 2002

본 연구에서는 균주의 배양과 동시에 생산물을 회수할 수 있는 동시추출공정을 건조질량의 $15{\sim}75$ %의 탄화수소를 생산한다고 알려진 B. braunii 배양에 적용하고자 한다. 일반적인 tow-phase 동시 추출공정의 적용시 B. braunii의 경우 생산된 탄화수소가 균주 외벽의 matrix에 강하게 부착되어 있기 때문에, two phase 추출공정 적용시 bubble solumn내에서 단지 폭기에 의한 교반만으로는 충분한 탄화수소의 회수율을 얻을 수가 없었다. 본 연구에서는 배양액과 유기용매층의 접촉기회를 증대시킨 two-stage 동시추출 공정을 개발하여 기존의 two-stage 동시추출 공정보다 2배 이상 높은 57 %의 탄화수소 회수율을 얻을 수가 있었고, 이를 회분배양후 후속분리공정으로 이용할 경우 6시간 추출후 62 %의 회수율을 얻을 수가있었다.