• 한국수산과학회지
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• 제15권4호
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• pp.255-262
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• 1982

1. 일반적으로 제주도 연안역에서의 영양염류 농도는 성분에 따라 차이가 있으나 표층보다 50 m이심에서의 농도가 $0.5\sim3$배 정도 높다. 2. 제주도 남동쪽 해역의 수온, 염분과 규산염, 질산염, 인산염, 용존산소의 농도 분포가 단조롭고 비교적 각 성분의 량도 적다. 3. 제주도 북쪽 해역은 한국남안연 안수의 영향을 받아 각 성분의 농도 분포가 복잡하고 그 변동 범위도 크다. 또 영양염류도 이 해역이 남동쪽 해역보다 풍부하다. 4. 제주도 남서쪽 해역은 황해저층냉수의 영향을 받아 영양염이 풍부하나 황해난류와 만나는 호경역이므로 그 분포상은 매우 복잡하다.

• 한국환경교육학회지:환경교육
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• 제19권2호
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• pp.96-107
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• 2006

Inquiry has great value in environmental education(EE). Being able to see the world environmentally through 'inquiry-based environmental education' can be an important value and goal of EE. In this study, we intended to develop an EE program of measuring activity of dissolved oxygen(DO), based on the theory of 'inquiry-based EE'. Especially, we recognized the potential that DO meter can be used in 'inquiry-based EE', and we tried to develop a model of inquiry-based EE using DO meter. As a result of this research, we present specific models of inquiry-based EE about how to perform measuring activity of DO and how to use the DO meter in laboratories and streams from the perspective of inquiry of water environment. In the process of program development, we considered organization of the inquiry process, use of concept and knowledge, scientific inquiry and insightful inquiry, integration, sustain-ability, content components of 'Environmental Studies for EE', developmental level and in-forest of students. The developed EE model is a scientific inquiry model, pursuing 'explanation' based on data collection. Through this model, we tried to make students see water environment more deeply. The developed program can be applied to various water environments, like laboratories, streams, ponds, etc. It can be more effective inquiry activity if we perform measuring activities simultaneously with PH, electrical conductivity, and turbidity meters.

• 한국작물학회지
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• 제49권4호
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• pp.284-288
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• 2004

The response of dissolved oxygen (DO) concentrations caused significant change in root number, root length, coleoptile length, shoot length and leaf age of seedlings. The genotypic difference in the effect of DO also highly significant (P<0.01) for all of the seedling traits. The number and length of root were extremely inhibited at the condition of $0.39\pm0.09$ DO concentration. While the coleoptile elongated markedly in the lowest DO concentrations, the shoot did not develop. The root growth was improved slightly at the $1.39\pm0.27mg L^{-1}$, however, there were no difference among genotypes at these two low DO concentrations. As the DO concentration become higher, the growth of root and shoot was improved remarkably. Root number, root length and shoot length was significantly different between $20\;and\;30^{\circ}C$ in DO rich and normal conditions, the development of those traits were apparently accelerated in high water temperature, however those traits of seedlings in DO deficiency were not different between the two temperatures except for shoot length. On the other hand the coleoptile length was not affected by the stagnant water temperature; it was stimulated by the low DO concentration. The competition of DO was greater as the seedling density was increased in the stagnant water, therefore the seedlings grown under high density have long and white coleoptiles, and the growth of roots and shoots was retarded severely.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2003년도 총회 및 춘계학술발표회
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• pp.188-191
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• 2003

Sing]e-well-push-pull tests were developed for use in assessing the feasibility of in-situ aerobic cometabolism of chlorinated aliphatic hydrocarbons (CAHs). The series includes Transport tests, Biostimulation tests, and Activity tests. Transport tests are conducted to evaluate the mobility of solutes used in subsequent tests. These included bromide or chloride (conservative tracers), propane (growth substrate), ethylene, propylene (CAH surrogates), dissolved oxygen (electron acceptor) and nitrate (a minor nutrient). Tests were conducted at an experimental well field of Oregon State University. At this site, extraction phase breakthrough curves for all solutes were similar, indicating apparent conservative transport of the dissolved gases and nitrate prior to biostimulation. Biostimulation tests were conducted to stimulate propane-utilizing activity of indigenous microorganisms and consisted of sequential injections of site groundwater containing dissolved propane and oxygen. Biostimulation was detected by the increase in rates of propane and oxygen utilization after each injection. Activity tests were conducted to quantify rates of substrate utilization and to confirm that CAH-transforming activity had been stimulated. In particular, the transformation of injected CAH surrogates ethylene and propylene to the cometabolic byproducts ethylene oxide and propylene oxide provided evidence that activity of the monooxygenase enzyme system, responsible for aerobic cometabolic transformations of CAHs had been stimulated. Estimated zero-order transformation rates decreased in the order propane > ethylene > propylene. The series of push-pu3l tests developed and field tested in this study should prove useful for conducting rapid, low-cost feasibility assessments for in situ aerobic cometabolism of CAHs.

• 생태와환경
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• 제35권2호통권98호
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• pp.133-140
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• 2002

본 연구는 실험실규모의 산화지 공법을 적용하였다. 체류시간 변화 및 산화지 형태가 처리율에 미치는 영향을 조사하였다. 조류의 광합성에 대한 유기물 제거율과 용존산소와의 상관관계는 야간에 비해 주간의 상관성이 더 높은 것으로 나타났고, 단일지의 경우는 체류시간 15일의 경우가 5일에 비해 상관성이 더 높은 것으로 조사되었다. 시간대별 DO변화는 체류시간 5일의 경우 다단산화지 내의 DO농포는 $42{\sim}19.8\;mg/l$를 나타내었고, 첫번째 조에 비해 후단으로 갈수록 높아졌다. 유기물 처리효율은 체류시간 5일이고, 4단 직렬식 다단 산화지 시설에서 제거효율이 더 높았다. 유기물 제거효율로 $TBOD_5$ 평균 제거율은 $49{\sim}83%$를 나타내었고, $SBOD_5$의 경우는 $87{\sim}92%$의 높은 처리율을 나타내었다. 또한 산화지내 조류생성량을 일정 농도로 유지시켜 주는 것이 산화지 공법의 처리율을 높일 수 있는 것으로 나타났다.

• 한국수산과학회지
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• 제48권3호
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• pp.314-321
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• 2015

We performed three sets of feeding trials to establish the optimal feed size (Exp-I), stocking density (Exp-II), and dissolved oxygen level (DO) (Exp-III) for olive flounder Paralichthys olivaceus. In Exp-1, four replicate groups of fish ($53.6{\pm}0.9g$) were fed commercial diets with three particle sizes (small, medium, and large). In Exp-II, fish ($30.0{\pm}0.1g$) were reared at four stocking densities (1.8, 3.5, 5.3, and $7.1kg/m^3$). In Exp-III, fish ($187{\pm}1.48g$) were reared under two different DO levels (2-3 and 6-7 mg/L). In Exp-I, fish fed the large-particle diet gained significantly more weight and had a lower feed conversion ratio than fish fed the small- and medium-particle diets. In Exp-II, fish reared at 1.8 and $3.5kg/m^3$ gained slightly more weight and had lower feed conversion ratios than fish reared at 5.3 and $7.1kg/m^3$, although these differences were not significant. In Exp-III, negative effects were observed in the low DO groups. Therefore, under our experimental conditions, the optimal feed particle size, stocking density, and DO level for olive flounder were 9-9.4 mm, $3.5kg/m^3$, and 6-7 mg/L, respectively.

• Corrosion Science and Technology
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• 제7권1호
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• pp.45-49
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• 2008

The cyclic polarisation technique was applied to determine the corrosion, primary-passivation, transpassive, and protection potential of AISI 316L stainless steels immersed in 3550-ppm NaCl solution containing sulfate in the content up to 3000 ppm. The solutions were kept constant at $27^{\circ}C$ and saturated by laboratory air. The solution pH was varied from 3 to 11. Each type of potentials was plotted in function of pH and linked as lines to determine the different zones in the constructed potential-pH diagram. The predominant regimes of the immunity, general corrosion, perfect passivation, imperfect passivation, and pitting corrosion were determined based on those lines of potentials. Comparing to the potential-pH diagram of specimens immersed in the aerated and deaerated 3550-ppm NaCl solutions, the addition of 3000-ppm $Na_2SO_4$ to these solutions increased the overall, perfect and imperfect, passivation regime by shifting the transpassive-potential line to the noble direction. However, it also widened the imperfect passivation area. The addition of $Na_2SO_4$ did not significantly affect the corrosion potential. It was found that the dissolved oxygen tends to negatively shift the transpassive-potential and protection-potential lines at all studied pH. The considerable effect of dissolved oxygen on corrosion and primary-passivation potentials could not be observed.

• 한국수산과학회지
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• 제34권3호
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• pp.190-193
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• 2001

바지락의 용존산소 농도에 따른 SFG (Scope for growth)의 변화를 알아보기 위하여 수온 $23\pm0.5^{\circ}C$와 일반해수에서 반수치사농도, 여수율, 호흡률, 암모니아 질소배설률 및 동화효율 등을 측정하였다. 바지락의 용존산소 농도의 감소에 따른 $LC_{50}$은 2.4mgDO$L^{-1}$였다. 여수율과 호흡률은 실험용액의 용존산소의 감소에 따라 대체로 감소하는 경향을 보인 반면, 암모니아 질소 배설률은 용존산소의 감소에 따라 증가하였다. 동화효율은 6.5mgDO $L^{-1}$에서는 $68.2\%$였으며, 3.5 mgDO $L^{-1}$ 이하의 농도에서는$29.8\~39.3\%$로 차이를 나타내지 않았다. 용존산소의 농도에 따른 SFG는 2.5mgDO $L^{-1}$ 이상에서는 양의 값을 나타내어 생존 및 성장이 가능한 것으로 나타났다.

• 한국해안·해양공학회논문집
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• 제34권3호
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• pp.47-57
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• 2022

본 연구에서는 진해만의 단일 정점 장기 모니터링 자료를 사용하여 LSTM 모형을 이용한 DO 농도 예측 및 결정 트리 모형을 이용한 빈산소수괴 발생 예측 연구를 수행하였다. LSTM을 이용한 DO 농도 예측 결과, Hidden node의 수가 증가할수록 모형의 복잡도가 증가하여 많은 Epoch을 요구하는 모습을 보였으며, 예측 시간 간격이 증가할수록 긴 Sequence length에서 높은 정확도를 보였다. 결정 트리를 이용한 빈산소수괴 발생 예측 결과, 30 day 예측에서 빈산소수괴 미발생 예측 정확도는 6 6 .1%로 발생 예측 정확도의 37.5%보다 상대적으로 높게 나타났다. 이는 결정 트리 모형이 DO 농도를 관측값보다 고평가하여 나타난 결과로 판단된다.

• 한국전자통신학회논문지
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• 제17권4호
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• pp.679-686
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• 2022

본 논문에서는 라즈베리파이 카메라와 DO(Dissolved Oxygen)센서를 사용하여 수중에 존재하는 녹조를 인식하고 녹조를 제거하는 기능을 갖는 녹조제거장치를 구현하였다. 라즈베리파이 보드는 카메라로부터 취득한 RGB 값을 HSV로 변환하여 녹조의 색을 인식한다. 이를 통해 녹조의 위치를 파악하고, DO 센서를 활용해 해당 위치의 용존산소량의 감소량이 기준치 이상일 경우 녹조제거장치가 녹조 제거 용액을 살포하도록 구동한다. 라즈베리파이의 카메라는 OpenCV를 활용하였고, 모터의 움직임은 DO 센서의 출력값과 카메라의 녹조인식 결과에 따라 제어한다. 녹조인식 및 녹조제거용액의 살포 기능은 아두이노와 라즈베리파이를 통해 구현되었으며 실험을 통해 제안한 이동식 녹조제거장치의 타당성을 검증하였다.