• 한국해안해양공학회지
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• 제13권3호
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• pp.245-253
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• 2001

속초 하수종말처리장에서의 하·폐수 해양방류에 따른 혼합구역 특성을 파악하기 위해 Huang et al.(1996)의 분석방법을 활용하여 혼합구역 모형을 수립하였다. 겨울철인 11월 하순부터 1월까지 약 2개월 동안 속초 해양방류수역에서 매시간 연속 관측된 해류, 해수 밀도의 성층자료, 그리고 하수 방류량자료를 입력한 모형모의를 통해 속초 해양방류수역에서 하수농도의 분포변화를 계산하였으며, 동일 기간에 관측된 조석자료를 토대로 약 15일 간격으로 구분한 기간 동안에 대해 평균한 농도분포를 제시하였다. 이 결과에 의하면 겨울철동안 평균된 최소희석률은 130으로 방류 하수의 혼합·의석이 대체로 양호했다. 그러나 해안에 평행한 연안류와 조류의 주 방향에 따라 방류하수의 혼합구역이 외해보다는 해변 쪽으로 확장되고 있어 인근 해수욕장의 수질악화에 큰 영향을 미칠 것으로 판단된다.

• 한국잡초학회지
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• 제16권2호
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• pp.114-121
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• 1996

유성지역에서 채종한 가막사리 종자의 휴면과 발아특성 및 초기 생장에 관한 조사를 통하여 발생생태를 파악하고, 기존 제초제에 대한 반응을 조사하여 벼 직파재배지에서 발생하는 가막사리의 효율적 방제를 위한 기초자료를 얻고자 실험한 결과는 다음과 같다. 1. 노지에서 채종한 종자를 실온건조, 실온습윤, 저온건조, 저온습윤, 고온건조 등의 조건에서 저장하였을 경우 저장 후 35일까지는 발아하지 않았다. 2. 저온습윤상태(모래층적)에 저장한 종자는 3개월 후부터 발아하기 시작하였으며 저장기간이 길어질수록 발아율도 증가되어 5개월 이후에는 70% 이상 발아되었고 9개월 이후에는 거의 모든 종자가 발아되었다. 3. 냉동(-20$^{\circ}C$), 고온(100$^{\circ}C$), 중탕(40$^{\circ}C$) 등의 물리적인 방법으로는 종자의 발아가 유기되지 않았다. 4. 농황산, $KNO_3$, 또는 지베렐린 용액에 종자를 침지처리하여도 발아가 유기되지 않았다. 5. Ethrel 용액에 종자를 파종하면 발아율이 증가되었는데 처리농도가 증가되면 발아율도 증가하여 250ppm의 농도에서는 90% 이상이 발아하였다. 그러나 1,000ppm의 농도에서는 오히려 발아율이 감소되었다. 6. 종자를 절단하여 파종했을 때 80% 정도의 발아율을 나타내었으며 발아한 유묘는 절단된 형태의 떡잎을 지니고 있었다. 7. 모래에 충적 저장한 가막사리 종자의 발아적온은 35~40$^{\circ}C$였으며 발아시 광을 요구하지 않았다. 8. 가막사리 종자가 담수조건에서는 발아되지 않았지만 생장에는 밭조건보다 유리하였다. 한편 완전히 침수된 가막사리 유묘는 전혀 생장하지 못하였으나 80% 정도 침수된 유묘는 정상적으로 생장하였다. 9. 제초제에 의한 가막사리 방제는 2엽기(葉期)이전에 처리하는 것이 효과적이며 실험에 사용한 제초제 중에서는 pyrazosulfuron-ethyl, linuron, bentazone 등이 우수한 효과를 나타내었다.

• 한국해양학회지
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• 제12권1호
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• pp.13-32
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• 1977

In order to determine the distributional ecology, and to investigate factors influencing these features, the diatom communities in plankton at depths of one, twenty-five, fifty, and seventy five meters in the area were studied and measured over a fifteen month of period. Measurements of environmental factors including temperature and salinity and algal nutrients such as phosphate, silicate, nitrate, and ammonia were also made at the same depths and locations. The results indicate that the size of diatom communities and the species population changes were heavily dependent upon to season and location parameters as well as nutrient concentrations and hydrographic factors. Major factors influencing population distributions varied with principal species responsible for dominant species and species sucession. Two distinct distributional patterns in total diatom crop were observed in the study area. Maximum standing crop observed during spring and/or summer were related to the concentration of nutrients available at the onset of the spring bloom on a large scale. On a small scale, however, the distributions of total diatom standing crops were significantly correlated with both season/location factors and with hydrographic parameters as well. Vertical stratification of diatoms was observed only in the presence of the thermocline in the water column. Within the study area there was some seasonal consistancy in the composition of the species groups. However, some species association in these environments may vary with the change of season.

• Clinical Endoscopy
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• 제57권1호
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• pp.73-81
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• 2024

Background/Aims: Upper gastrointestinal bleeding (UGIB) is a life-threatening condition that necessitates early identification and intervention and is associated with substantial morbidity, mortality, and socioeconomic burden. However, several diagnostic challenges remain regarding risk stratification and the optimal timing of endoscopy. The PillSense System is a noninvasive device developed to detect blood in patients with UGIB in real time. This study aimed to assess the safety and performance characteristics of PillSense using a simulated bleeding model. Methods: A preclinical study was performed using an in vivo porcine model (14 animals). Fourteen PillSense capsules were endoscopically placed in the stomach and blood was injected into the stomach to simulate bleeding. The safety and sensitivity of blood detection and pill excretion were also investigated. Results: All the sensors successfully detected the presence or absence of blood. The minimum threshold was 9% blood concentration, with additional detection of increasing concentrations of up to 22.5% blood. All the sensors passed naturally through the gastrointestinal tract. Conclusions: This study demonstrated the ability of the PillSense System sensor to detect UGIB across a wide range of blood concentrations. This ingestible device detects UGIB in real time and has the potential to be an effective tool to supplement the current standard of care. These favorable results will be further investigated in future clinical studies.

• Ocean and Polar Research
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• 제29권3호
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• pp.217-231
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• 2007

To explore limiting factors of spring bloom caused by waste disposal after dumping activity commenced in the Yellow Sea, we used a 1-dimensional temperature-ecological coupled model. The vertical structure of temperature and vertical diffusivity (Kh) are calculated by the temperature model with sea surface temperature using the 2.5 layers turbulence closure scheme. The ecological model applied results at the temperature model consisted of five state variables (DIN, DIP, phytoplankton, zooplankton, and detritus) forced by photosynthetically available radiation. We simulate year-to-year variations of plankton and nutrients using the coupled model from 1998 to 2000 and compare results of the model with observed data. It turned out that temperature is the growth factor of spring bloom in dumping area. During the winter the weak stratification made sufficient supply of the accumulated nutrients from the sea bed into the upper water column and led to the bloom in the coming spring. Radiation also turned out to be another important factor of spring bloom in the study area. Insufficient radiation of March 1999 showed low chlorophyll-a concentration despite sufficient nutrients in the surface.

• 환경영향평가
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• 제17권6호
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• pp.349-356
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• 2008

This paper aims to understand the effects of a turbidity flow intrusion on eutrophication in Daecheong Dam Reservoir. CE-QUAL-W2, a two-dimensional hydrodynamic and water quality model, is applied. The elevation of the reservoir water surface is used to validate the hydrodynamic model parameters and maximum fluctuations in the water surface elevations reaches about 1 m in the reservoir. During the heavy storm season, July, the thermocline submerged to less than 30 m below the surface. The thickness of the thermocline also reduced to 10 to 15 m. While the average TSS in June, the beginning of the monsoon was still low but it peaked in July due to heavy rainfall. Vertical profiles of the TSS regime in July indicated higher concentration in upper water layers and then the regime moves gradually downward in accordance with the time lapse. Due to the dam spillway opening, high concentrations of TSS attributed to storm turbidity ascended to the upper water layer by following the upward current movement and then, the regime precipitated to a layer below 30 to 40 m after September.

• Ocean Science Journal
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• 제41권3호
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• pp.181-189
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• 2006

Frontal areas between warm and saline waters of the Kuroshio currents and colder and diluted waters of the East China Sea (ECS) influenced by the Changjiang River were identified from the satellite thermal imagery and hydrological data obtained from the Coastal Ocean Process Experiment (COPEX) cruise during the period between March $1^{st}$ and $10^{th}$, 1997. High chlorophyll concentrations appeared in the fronts of the East China Seas with the highest chlorophyll-a concentration in the southwestern area of Jeju Island (${\sim}2.9\;mg/m^3$) and the eastern area of the Changjiang River Mouth (${\sim}2.8\;mg/m^3$). Vertical structures of temperature, salinity and density were similar, showing the fronts between ECS and Kuroshio waters. The water column was well mixed in the shelf waters and was stratified around the fronts. It is inferred that the optimal condition for light utilization and nutrients induced both from the coastal and deep waters enhances the high phytoplankton productivity in the fronts of the ECS. In addition, the high chlorophyll-a in the fronts seems to have been associated with the water column stability as well.

• International Journal of Automotive Technology
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• 제8권2호
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• pp.127-135
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• 2007

The objective of this study is to analyze the effect of velocity and vorticity on stratified mixture formation in the visualization engine. In order to investigate spray behavior, the pray velocity is obtained through the cross-correlation PIV method, a useful optical diagnostics technology and the vorticity calculated from the spray velocity component. These results elucidated the relationship between vorticity and entropy, which play an important role in the diffusion process for the early injection case and the stratification process for the late injection case. In addition, we quantified the homogeneous diffusion ate of spray using entropy analysis based on Boltzmann's statistical thermodynamics. Using these methods, we discovered that the homogeneous mixture distribution is more effective as a momentum dissipation of surrounding air than that of the spray concentration with a change in the injection timing. We found that the homogenous diffusion rate increased as the injection timing moved to the early intake stroke process, and BTDC $60^{\circ}$ was the most efficient injection timing for the stratified mixture formation during the compression stroke.

• 환경영향평가
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• 제19권3호
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• pp.247-257
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• 2010

Watershed runoff and turbid water dynamics were simulated in the Youngju Dam, being constructed. The runoff flow and suspended solids were simulated and then thermal stratification and turbid water current in the reservoir were predicted by HSPF and CE-QUAL-W2 model, respectively. Considering selective withdrawal, we hypothesized 3 withdrawal types from the dam, i.e. surface layer, middle layer and the lowest layer. The maximum concentration of SS was 400mg/L in reservoir and it was decreased by the withdrawal. The inflowed turbid water fell to 30 NTU after 12 days regardless of the withdrawal types, but the surface layer withdrawal was a better type at turbid water discharge than the others. In current environmental impact assessment(EIA), we concluded that runoff and reservoir water quality predicted by HSPF and CE-QUAL-W2 was desirable, and appropriate parameters were selected by continous monitoring after EIA.

• 한국자원식물학회:학술대회논문집
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• 한국자원식물학회 2018년도 춘계학술발표회
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• pp.60-60
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• 2018

This study was carried out to develop the seed propagation method of Dicenta spectabilis (L.) Lem. which is an ornamental plant native to Korea. In the previous studies, it was found that the seeds of D. spectabilis were morphophysiologically dormant (MPD), and high and low temperature of stratification were continuously required for the embryo growth and germination of the seeds. Especially, it was most effective to store for 1 month at $20^{\circ}C$ and then to transfer to $4^{\circ}C$. The treatment of $GA_3$ was carried out to promote embryo development and germination. The seeds were submerged in 100, 200 or $500mg{\cdot}L^{-1}$ $GA_3$ for 72 hours and then stored at various conditions as follow. The temperature conditions disposed of this experiment were 1 month at 10, 15, 20, and $25^{\circ}C$ or 2, 4, 8, and 12 months at $4^{\circ}C$, respectively. As a result, the length of embryo and germination rate of the seeds were the best when stored at $4^{\circ}C$ for 8 months after $500mg{\cdot}L^{-1}$ $GA_3$ treatment. Besides, when the seeds stored at $4^{\circ}C$, significant differences in embryo length and germination rate were shown with $GA_3$ concentration and storage period. It was also proved that high-concentration of $GA_3$ could replace the high temperature and could promote germination. Consequentially, the D. spectabilis seeds were classified into intermediate simple levels among MPD types.