• Journal of Environmental Impact Assessment
• /
• v.27 no.2
• /
• pp.170-180
• /
• 2018

Highland fields are concentrated in the Jaun area of Hongcheong-gun, a large amount of sediments are discharged from the highland fields. The sediment runoff affect the turbidity and water quality of the Soyang Lake, furthermore adversely affect water supply source of the capital region. There are several kinds of BMPs(Best management practices) to decrease the sedimentrunoff from the highland fields. Although construction cost of multistage sedimentation basins is very high, there is no actual survey data for the removal efficiency of suspended sediments and water quality in our country. In this study, stormwaterinflow and outflow of the multistage sedimentation basins were surveyed, and the removal efficiency of nonpoint source pollutants were analyzed. The stormwater survey results fortwo rainfall events show thatremoval efficiencies of SS, BOD and TP loads in the multistage sedimentation basins are 35%~62%, 24%~55%, 35%~58%, respectively. Although the measured efficiencies of the basins were lower than the theoretical efficiency, the proper operation and management can improve the removal rate of the basins. Turbid water problem in the upper parts of the Soyang River can be managed effectively through the additional installation of multistage sedimentation basins.

• Journal of The Korean Society of Grassland and Forage Science
• /
• v.28 no.4
• /
• pp.289-294
• /
• 2008

This experiment was conducted at college of Agriculture and Life Science in Chungnam National University from September, 2004 to June, 2007 in order to evaluate the mixture possibility between barley and rye in the area of Daejeon. Rye (cultivar; Koolgrazer) and barley (cultivar; Daeyeon Bori) were set for the experiment. The experiment was arranged in four treatments: R100 (rye 100%), R60 + B40(rye 60% + barley 40%), R50% + B50% (rye 50% + barley 50%), and R40% + B60% (rye 40% + barley 60%). The experiment was repeated three times in the randomized complete block. The average dry matter (DM) yield for three years of R100 weighed 9,282 kg and its DM yield was higher than any other DM yield. The higher the barley seed rates are, the lower the DM yield is (p<0.05). As the barley seed rates increased 40%, 50%, and 60% respectively, its vegetative percentage tended to increase 30%, 41%, and 47%, but the barley vegetative percentage against its seed rates did bring forth somewhat low results. Compared with R100, the contents of crude protein (CP) and in vitro dry matter digestibility (IVDMD) got higher as the barley seed rates became higher, while the contents of NDF, ADF, cellulose, and lignin were lower (p<0.05). Compared with R100, the yields of crude protein dry matter (CPDM) and digestible dry matter (DDM) showed lower in the any mixed barley (p<0.05). Thus, in case of using barley mixed with rye in the area of Daejeon, it seems to be quite difficult, unless the supply of high-productive barley variety is followed, to enhance the yields of DM, CPDM, and DDM.

• Korean Journal of Ecology and Environment
• /
• v.43 no.3
• /
• pp.400-408
• /
• 2010

The growth and microcystins production characteristics of three species of Microcystis (M. aeruginosa, M. ichthyoblabe, M. viridis) isolated from Yeongchun dam and Ankei dam in Kyungpook Province, South Korea were investigated at temperatures of $15{\sim}35^{\circ}C$ and light intensities of $35{\sim}180\;{\mu}mol\;m^{-2}\;s^{-1}$. All of the three species exhibited the highest growth rates (${\mu}_{max}$) over the $30^{\circ}C$. The maximum growth rates of M. aeruginosa and M. ichthyoblabe was observed at $70\;{\mu}mol\;m^{-2}\;s^{-1}$, while M. viridis showed maximum growth rate at $35\;{\mu}mol\;m^{-2}\;s^{-1}$. The maximum production of total microcystins was observed at $20^{\circ}C$, and the production of microcystins decreased according as temperature increase. The highest microcystins production of M. aeruginosa, M. ichthyoblabe and M. viridis observed at light intensities of $120\;{\mu}mol\;m^{-2}\;s^{-1}$, $70\;{\mu}mol\;m^{-2}\;s^{-1}$ and $35\;{\mu}mol\;m^{-2}\;s^{-1}$, respectively. The concentration of microcyst in production and microcystin types of three species according to temperatures and light intensities showed clear difference between the species.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.41 no.3
• /
• pp.233-239
• /
• 2013

A 100 W fuel cell system using chemical storage method has been applied for a propulsion system of the SUAV(Small Unmanned Aerial Vehicle). A fuel cell and battery have been combined for both the small/light hydrogen generation control system and the hybrid power supply system. A small hydrogen generation device was implemented to utilize NaBH4 aqueous solution and dead-end type PEMFC system, which were evaluated on the ground and by the flight tests. The system pressurized at a 45kpa stably operates and get higher fuel efficiency. The pressure inside of the hydrogen generation control system was maintained at between 45 kPa and 55 kPa. The 100W fuel cell system satisfies the required weight and power consumption rate as well as the propulsion system, and the fuel cell system performance was demonstrated through flight test.

• Archives of Plastic Surgery
• /
• v.37 no.5
• /
• pp.577-582
• /
• 2010

Purpose: When reconstruction for patients who have the large contralateral breast or a following large defect after mastectomy is required, conventional pedicled TRAM flap shows the unpredictable occurrence of fat necrosis and skin flap loss in a relatively high percentage due to insufficient blood supply. In an effort to obtain more stable TRAM flap blood circulation, we have performed a supercharged technique using deep inferior epigastric perforators (DIEP) with conventional pedicled TRAM flap. Methods: From September of 2006 to December of 2008, Fourteen supercharged TRAM flap were performed for breast reconstruction after modified radical mastectomy. The contralateral DIEP was anastomosed to the internal mammary vessels in contralateral pedicled TRAM flap or thoracodorsal vessels in ipsilateral pedicled TRAM flap. Nutrient vessels were selected by Multi-Detector Computed tomography (MD-CT) modalities. For the nutrient vessel, we used deep inferior epigastric vessels (DIEV) of the ipsilateral side in 8 patients, DIEV of the contralateral side in 6 patients. In addition, for the recipient vessel, we used thoracodorsal vessels in 8 patients, internal mammary vessels in 5 patients, intercostals artery perforators in 1 patient. Results: The mean age was 46.8 years and the average follow-up interval was 14 months. There were 11 immediate and 3 delayed breast reconstructions. Fat necrosis incidence rate in supercharged TRAM group was lower than in conventional TRAM flap group. There were no differences of the incidences of abdominal hernia in both groups. Conclusion: The supercharged TRAM flap produces an improvement in vascularity that permits use of all four zones of the flap. The breast reconstruction with supercharged technique is reliable and valuable methods which provide sufficient soft tissue from abdomen without significant complications.

• Journal of the Korean Vacuum Society
• /
• v.16 no.3
• /
• pp.161-166
• /
• 2007

Photovoltaic (PV) technology permits the transformation of solar light directly into electricity. For the last five years, the photovoltaic sector has experienced one of the highest growth rates worldwide (over 30% in 2006) and for the next 20 years, the average production growth rate is estimated to be between 27% and 34% annually. Currently the cost of electricity produced using photovoltaic technology is above that for traditional energy sources, but this is expected to fall with technological progress and more efficient production processes. A large scale production of solar grade silicon material of high purity could supply the world demand at a reasonably lower cost. A shift from crystalline silicon to thin film is expected in the future. The technical limit for the conversion efficiency is about 30%. It is assumed that in 2030 thin films will have a major market share (90%) and the share of crystalline cells will have decreased to 10%. Our research at Sungkyunkwan University of South Korea is confined to crystalline silicon solar cell technology. We aim to develop a technology for low cost production of high efficiency silicon solar cell. We have successfully fabricated silicon solar cells of efficiency more than 16% starting with multicrystalline wafers and that of efficiency more than 17% on single crystalline wafers with screen printing metallization. The process of transformation from the first generation to second generation solar cell should be geared up with the entry of new approaches but still silicon seems to remain as the major material for solar cells for many years to come. Local barriers to the implementation of this technology may also keep continuing up to year 2010 and by that time the cost of the solar cell generated power is expected to be 60 cent per watt. Photovoltaic source could establish itself as a clean and sustainable energy alternate to the ever depleting and polluting non-renewable energy resource.

• Journal of Wetlands Research
• /
• v.15 no.4
• /
• pp.461-469
• /
• 2013

Even though a sewer rehabilitation BTL project has been executed throughout the nation with the input of a significant amount of budget, the overall review on effectiveness of the project is insufficient. And disputes over effectiveness of the project and of the employment of I/I indexes for evaluation of the project are continued due to reliable issues of flux data which has been measured after completion of certain projects and excessive amounts of I/I. Thus, this study has reviewed effectiveness of the project, current status and problems of the installation of fixed flow meters as well as countermeasures based on 15 projects subject to the operation performance evaluation after the completion of the project. The review on operation of the project has revealed that sewer rehabilitation BTL projects are significantly effective and highly effective on reducing a rate of infiltration water. The review on the employment of proper countermeasures for main issues revealed during the investigation on the installation and operation of fixed flow meters has shown that such countermeasures could result in securing more reliable flux data.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.16 no.4
• /
• pp.339-344
• /
• 2010

Oxygen depleted water mass can damage aquatic animals not only in direct way but also in indirect way by generating toxic substances including occurrence of hydrogen sulfide and ammonia which are also highly detrimental to animal life in the water mass. An oxygen dissolution device was developed, which makes turnover of the oxygen rich (over 20 mg/L) surface water down to the bottom where hypoxia is evident and tested the device in terms of oxygen recovery in the oxygen depleted bottom water. the device with turnover rates of $3.6\;m^2$/min at the liquid oxygen injection rate of 48~26.3 L/min could recover dissolved oxygen level to 7~25 mg/L at depth 7 m to lead to the dissolution level of over 90% by the supply of liquid oxygen. The running advantage of the device is that it does not require any auxiliary tank and higher energy for operation. Therefore, it can be highly useful device to relieve damages to the farmed animals in the oxygen depleted waters.

• Journal of fish pathology
• /
• v.6 no.2
• /
• pp.205-218
• /
• 1993

On the development of hirame(Paratichtys olivaceus) culture, outbreak of scuticociliata infection was reported to cause severe damage in Japan. To establish effective measures for isolation and cultivation of this ciliate, we tried to culture this pathogenic ciliate using medium for bacteria and fish cell lines in vitro. Scuticociliata from the brain tissues of infected fish was aseptically inoculated to CHSE-214 cells cultured in MEM-10 without antibiotic. Scuticociliata grew well and the number of ciliate reached $10^6\;cells/ml$ at temperatures of $15^{\circ}C$ to $20^{\circ}C$ for 10d. The number of ciliate cultured in the cell lines is 10 times higher than the numbers cultured in the liquid medium alone. This ciliata could be cloned by dilution method. Scuticociliata isolated could grow well on 42 different cell lines that were established from marine fish, warm freshwater fish, and salmonids. This ciliate could be preserved in liquid nitrogen for more than 6 months. Subsequently, we observed the optimal temperature and salinity for growth, and tested the sensitivities of this organism to formaldehyde, flagyl(Metronidazole), Ekuteshin(Combination compound of sulfamonometoxin and ormethoprim), and ozonixation. Optimal temperature for growth was $25^{\circ}C$ and salinity was 1.0 to 1.5%. Washed scuticociliata was killed by formaldehyde at the concentration of 50ppm for 10min, but was not completely killed even at a high concentration of 400ppm for 20min in MEM-5. Flagyl and Ekuteshin can inhibit the growth of scuticociliata at the concentration of 1,000 and $100{\mu}g/ml$ in MEM-10, respectively. More than 99% of this scuticociliata could be killed by ozonization at a dose equivalent to $1.0mg/\ell$ oxidant for 30sec in sea water. Isolated scuticociliata showed the pathogenicity to the cultured hirame by artificial infection(I. P. injection, $10^5\;cells$/fish). The number of scuticociliata in the water could be counted by most probable number(MPN) method using tissue culture, and the minimum detectable number was $1.8\;cells/\ell$. The number in the reservoir tank for water supply to the culture tank was 110 cells/l. After cleaning by elimination of the sediments from of the reservoir tank and disinfected with formaldehyde, number of scuticociliata decreased and was counted less than $1.8\;cells/\ell$ and infection rate of cultured hirame was decreased.

• Journal of Korea Port Economic Association
• /
• v.24 no.2
• /
• pp.289-315
• /
• 2008

In Korea-China shipping route, the level of freight rate has been maintained very low for last two decades not only because supply of shipping capacity is higher than its demand but also because the route was regulated by the two governments. An examination is made of the effects of openness of Korea-China Liner Shipping Route on competitiveness of Korean-flag Liner Shipping companies. This task is undertaken by detailing the development of the cargo sharing respectively by shipping companies of each country. Then it is suggested the ways to cope with the new environmental changes in Korea-China liner shipping route for the future by examining the future strategies for Korean-flag companies by in-depth interviews with major shipping companies.