• Journal of Plant Biotechnology
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• v.33 no.2
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• pp.117-122
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• 2006

Comparative studies on medium supply in bioreactors (raft, immersion and ebb and flood) have revealed that multiplication and growth of Alocasia Amazonica were greatest in the raft system, while lowest in ebb and flood system. In the raft system, the basal part of the shoots was continuously in contact with medium, which enabled a constant uptake of nutrients as well as aeration to the explants. The number and the size of leaf stomata were higher in the raft system compared with immersion and ebb&flood system. In the immersion system, plantlets were deformed and epidermal cells in leaves were irregular with a large intercellular space. The results suggested that the medium supply should be controlled properly to maintain normal and healthy plantlets during liquid cultures in bioreactors Which affects morphology and physiology Of the plantlets.

• Journal of Korea Water Resources Association
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• v.45 no.9
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• pp.915-928
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• 2012

Han River estuary (HRE) is located at the middle of the western coast of Korea, and tidal currents were measured at 4 stations in this estuary during the winter season, and previously observed tide data was analyzed. The results of amplitude ratio of $M_4/M_2$ showed that increasing upward to estuary in the HRE. Tide harmonic constants of relative phase $2M_2-M_4$ represent flood dominance, with under 180 degree. But this method has a limit of analysis that typically based on the non-linear distortion of the tidal current in tidal lagoon system where freshwater discharge is assumed to be relatively small. The results of statistically tidal current data indicated that ebb current velocity would be great unlike tide data. Ebb and flood duration time is calculated by slack time of tidal current showed that ebb duration time is longer than flood. The results of correlation of analysis show high value (0.9) between tidal current stations from Incheon harbor to north entrance of Yeomha channel. We reconstructed to find the reasons for the features of ebb dominance the results of harmonic analysis. As major component ($M_2$) in combination with shallow water component ($M_4$), the tidal curve was presented flood dominance that has a flood current is stronger. However, these curve were changed to ebb dominance add up the non-harmonic components that had ebb direction flow by calculated tidally averaged current. The characteristic of enhancement on ebb is showed around the Yeomha channel in the HRE, because averaged flow which acts seaward such as long-term tidal current components due to non-linear effect and freshwater which overcome the flood current.

• Magazine of the Korean Society of Agricultural Engineers
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• v.10 no.1
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• pp.1394-1408
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• 1968

The tidal discharge is defined as the quantity of water flowing through a certain cross-section per unit of time, in contrast to river discharges, tidal discharges change periodically in magnitude and direction. Thus the total volumes of water flowing into again out of the system-called flood volume and ebb volume, respectively, depend on both the tidal and the river discharges. To ditermine the tidal discharge and the flood and ebb volumes of the Yong-san river, the discharges were measured at spring, mean and neap tide and simultaneous gage reading were taken at Samhak-do, Lower Myo-do, Myongsan-ni and Naju. The general procedure for measuring the tidal discharges was as follows. First, several cross-sections were measured and one of them was chosen. First, several cross-sections were measured and one of them was chosen. Then verticals were serected in the chosen cross section. Because comparatively few verticals should be representative of the discharge distribution over the river profile, the selection was done in accordance with the somtimes irregular bottom profile. The velocities were measured with the same current meters. The observations which included water level readings were continued for a period of about 13 hours. The current direction meter, a pyramid shaped resistance body, suspend in the water on a thin wire. The bubble in a circular tilting level fixed to the wire indicates the direction of the current. Reading were taken at intervals of 1m for depths of 10m or less, and for depths over 10m at intervals of 2m, going downwards and upwards. The averages of the two velocities were used for the computation of the discharges. The discharges and the flood and ebb volumes were ditermined by a graphical method. The mean velocities, corrected for their direction when necesary, were ditermined for each time interval and each vertical, and these velocities were plotted against the time. The resulting curves show possible mistakes very clearly, and the effect of observation errors could be reduced. The corrected velocities read from the curve at half-hour intervals were multiplied by the depth at the virtical at the corresponding time. The discharges thus found were ploted against the position of the vertical in the transit and joined by a smooth curve, integration of the curve rendered the total discharges as they occurred of half-hour intervals. Plotting these total discharges against the time yeilded during the day. The flood and ebb volumes were obtained by integration of the total discharge curve.

• Journal of Environmental Science International
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• v.20 no.6
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• pp.679-686
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• 2011

The characteristics of circulation in the coastal area of Jeju Harbor in Korea was examined using the Princeton Ocean Model(POM) with a sigma coordinate system. The result of numerical analysis well corresponded to the observed current data. The velocity at offshore was stronger compared to coastal area during the both period of in maximum flood and maximum ebb of spring tide. According to mean wind velocity, the tidal velocity at the shallow area of Jocheon was slightly increasing during maximum ebb. The effect of wind on the circulation was stronger in shallow area and showed rapid change with depth.

• Journal of Plant Biotechnology
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• v.31 no.2
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• pp.127-132
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• 2004

A suitable bioreactor culture system for shoot proliferation and bulblet formation of Allium victorialis var. platyphyllum Makino was established. Uptake of soluble carbohydrates in different bioreactor culture systems was also analyzed during the entire culture period. Optimal conditions for multiple shoot formation were determined in raft culture (RC) and modified raft culture system (MRC) (13-15 per explant) in which the explants were placed on a net contacting liquid medium. For bulblet formation and enlargement, 93.4％ of shoot clumps formed bulblets at the basal part. Furthermore, they were uniform in size when cultured with ebb & flood system (E&FS). Bulblets harvested from RC and MRC showed vigorous rooting, however, their growth was not uniform. Whereas soluble carbohydrate contents in the bulblets cultured in E&FS were low, starch content was high. Sucrose, glucose and fructose concentrations in the medium of E&FS culture system decreased as bulblet formation and enlargement proceeded, suggesting that external sucrose is taken up to by the cells before it is hydrolyzed.

• Proceedings of the Korean Society of Life Science Conference
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• 2005.04a
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• pp.240-240
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• 2005

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.20 no.2
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• pp.232-237
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• 2008

A method to generate electric power from small scale water tank. For this purpose, manufacturing tank is investigated, measuring water level change at any time, and finally comparing experimental and theoretical value, are performed. Inner and outer tank are made to simulate flood and ebb generation. Two sets of pipe are connected between tanks, and experiments are performed under varying flowrate. Coefficients of flowrate are calculated comparing water level change data and theoretical value. Measured and theoretical water levels are highly correlated, and this ascertains that analytical equation simulates real water level changes well. Flowrate change depending on the existence of propeller and valve, on flood and ebb generation, shows the necessity of experiments in the process of manufacturing electric power system. Moreover, total energy calculated from experimental data agrees well with that of theoretical equation. In spite of small tidal power output, this generating system with optimum water tank can be applied to any place where high water level change occurs, and can make a contribution to producing new and renewable energy consequently.

• Journal of Environmental Science International
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• v.26 no.3
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• pp.325-334
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• 2017

To understand the changes in physical parameters and phytoplankton size structure caused by tides, a fixed station in the Youngsan River estuary was monitored at 2-h intervals, on April 28, 2012 and August 12, 2012. No clear relationship was observed between the temperature and salinity changes and tidal levels in April. However, in August, temperature decreased during the ebb tide and increased during the flood tide, while salinity showed the opposite trend. In addition, there was no specific change in the phytoplankton biomass corresponding to tidal levels in April. In August, the total chlorophyll a and the biomass of net phytoplankton (>$20{\mu}m$) increased almost 20 times during the ebb tide and decreased during the flood tide. The biomass of nanophytoplankton (<$20{\mu}m$) showed a similar variation in response to tidal level changes. In April, the relationship between percent contributions of phytoplankton size structure and tidal levels was not clear. In August, the net phytoplankton was dominant in the early stage and nanophytoplankton was dominant in the later stage, while contribution of nanophytoplankton and net phytoplankton increased at high tide and low tide, respectively. Therefore, in April, other factors such as freshwater discharge were more important than the tide, whereas in August, when no freshwater discharge was recorded, the changes in semidiurnal tides influenced the physical parameters and phytoplankton dynamics. These results could contribute to the understanding of phytoplankton dynamics in the Youngsan River estuary.

• Korean Journal of Plant Tissue Culture
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• v.28 no.3
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• pp.135-140
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• 2001

A series of studies were carried out to establish micropropagation system, using airlift bioreactors (ebb $\varepsilon$ flood type, 5 L), of Lilium oriental hybrid 'Casa Blanca'. The bulblets with swollen basal plate were formed from bulb scales, then proliferated to bulblet clusters with swollen basal plate. Finally normal bulblets were formed from the sections. Bulblet formation and proliferation with swollen basal plate were not accomplished entirely in liquid culture of 5 L airlift bioreactors, but leafy bulb scales grew vigorously. Bulblet clusters with swollen basal plate were proliferated by periodic immersion culture. Bulblet proliferation was not affected by light, but scale leaves grew under light. MS medium containing 2.0 mg/L benzyl adenine (BA) and 0.3 mg/L indole acetic acid (IAA) was favorable to the bulblet proliferation with swollen basal plate. In liquid culture of 5 L bioreactors, bulblets from bulblet sections with swollen basal plate grew vigorously on MS medium with 70 g/L sucrose. It was effective for bulblet growth to replace the new medium after 8 weeks in culture during 16 weeks of cultural period. 15 g injection of bulblet sections as a cultural material was suitable for bulblet growth in 5 L bioreactors.

• Proceedings of the KSRS Conference
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• 2004.10a
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• pp.318-321
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• 2004

The damage scale and damage area in the coast have been increased dramatically because of calamities such as typhoon. tidal wave. flood and storm. Especially. 409 cases. which reach to about $40.9\%$ of natural disasters of 1,000 cases for the recent 15 years have happened on coast area. More than $40\%$ of natural disasters also occurred every year is happening in coastland. Therefore, there is a great need to construct all related GIS database such as atmospheric phenomena (typhoon. tidal wave, flood and storm). harbor facility, harbor traffic and ebb and flow. Furthermore. the certain system should be developed and integrated with NDMS (National Disaster Management System) by using 3D web GIS technology. In this study. the coast disaster area management system was designed and developed by using 3D web GIS technique so that the coast disaster area could be monitored and managed in real time and in visual. Finally. the future disaster in coast area could be predicted scientifically.