• Journal of the Korean Society of Marine Environment & Safety
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• v.5 no.2
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• pp.57-65
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• 1999

The in situ observations and the seawater analyses were conducted at all seasons from July 1996 to April 1999 for the purpose of describing the characteristics of seasonal variations of water quality in Mokpo harbour, Korea. Vertical stratification started to be formed in water column in spring, developed in summer and disappeared in fall. In summer, vertical density distribution of water column was found to be in stable structure with lower temperature and higher salinity of bottom water, and the vertical mixing of water between surface and bottom layers was restricted. In winter, however, surface water was found to be similar to bottom water in temperature and salinity, and water column was in unstable structure and in well-mixed condition between surface and bottom waters. The saturation percentage of dissolved oxygen(DO) in bottom water of inner part of Mokpo harbour at all seasons was shown to be decreased to the third grade or under the third grade of Korean standards of seawater quality. In particular, dissolved oxygen was oversaturated in surface water and undersaturated in bottom water in summer, due to stratification and organic pollution. The difference of DO concentration between surface and bottom waters was found to be greater in spring and summer than in fall and winter, due to stratification and photosynthesis of phytoplankton. The concentrations of chemical oxygen demand(COD) over the entire waters of Mokpo harbour were found to fluctuate from below the third grade to the first grade of Korean standards through all seasons and COD concentrations of same seasons were shown to be different year after year. In particular, in view of COD, the annual average seawater quality of Mokpo harbour was evaluated to be in third grade of Korean standards, due to organic pollution. The average COD of surface water was greater than that of bottom water in spring and summer, due to the autochthonous COD caused by production of phytoplankton in surface waters, while the average COD of surface water was similar to that of bottom water in fall and winter, due to the vertical mixing of water between surface and bottom layers.

• Korean Journal of Ecology and Environment
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• v.38 no.4 s.114
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• pp.435-438
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• 2005

We observed the physical, chemical, and biological characteristics of an acidic lake, Lake Katanuma, from 1998 to 2002 at weekly or biweekly intervals, except during the winter. This volcanic lake has a dimictic thermal pattern. In summer, the volcanic heat supply at the lake bottom results in weak thermal stratification. In 1998, 1999, and 2002, short-term holomixis was observed during the stratification period, when the anoxic, hydrogen sulfide-rich water from the hypolimnion spread across the entire lake. In contrast, distinct short-term holomixis did not occur during the stratificatlon period in 2000 and 2001. However, the early onset of the autumn turnover in August 2000 and 2001 caused anoxic conditions to persist throughout the entire water column for more than 2 weeks. The anoxic and hydrogen sulfide-rich conditions affected population densities of chironomid larvae (Chironomus acerbiphilus) and planktonic algae (Chlamydomonas acidophila), both dominant species in Lake Katanuma. Thus, the interannual variations of limnological characteristics influenced the seasonal population changes of these species.

• Proceedings of the Korea Water Resources Association Conference
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• 2005.09a
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• pp.11-12
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• 2005

With the great advances in process understanding, sensor and instrumentation technology and modelling capability it is important to ask what if any practical benefits can the lake manager and operator look forward to. Here, we examine some of the more important problems facing operators of drinking reservoirs, hydro-lakes and lakes used predominantly for recreation and the environment. In drinking reservoirs the main problems originate from increased loadings of nutrients leading to increased biomass and biomass that may give rise to toxins, of anthropogenic chemicals such as metals and synthetic organics and of pathogens of different types. Hydro-lakes are predominantly plagued by problems arising from low oxygen levels in the hypolimnion and in recreational and environmentally sensitive lakes the biggest challenge for the operator is to maintain an existing or establish a new trophic hierarchy or protect the water body from foreign species. The control variables that are at an operator's disposal are the choice of lake water level, the modification of the water colunm stratification via a de-stratification system, the modification of the lake flow path with flow intervention. curtains, intervention in the catchments to modify the loadings flowing into a lake, manipulation of the trophic chain with introduction of new species and chemical dosing, the latter being of marginal use in a large lake. Each of these options is cost effective under certain-circumstances. We endeavour to provide a users guide for their application and show how, especially new instrumentation and modelling methodologies may be used to achieve an effective intervention.

• Korean Journal of Plant Resources
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• v.27 no.3
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• pp.263-270
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• 2014

Loranthus tanakae (Franch. & Sav.) is an endangered species of mistletoe, distributed in Korean peninsula. The objective of our research is to determine the effect of storage duration and conditions [air flow (AF) and air tight (AT)] at different temperatures for survivability and germination of mistletoe seeds, and also to monitor the effect of seed scarification on germination in vitro. The result revealed that the seeds stored in natural conditions (no stratification) showed highest survival rate of 100% and retained up to 93.3% even after two months of storage in natural conditions and showed higher germination percentage (90%) compare to after ripened seeds. However, the seed stored at $0^{\circ}C$ decreased the germination percentage (ranged from 63 to 73%). Therefore, it can be confirmed that mistletoe does not need after ripened treatment to promote germination. Our research also showed that the storage of L. tanaka seeds in freezing temperatures of $-20^{\circ}C$ and in room temperature for long time either in AT or AF conditions caused the loss of survival and germination rate. On the other hand, the chemical scarification (0.01N HCl incubation for 12 hrs. at $38^{\circ}C$) method was proven more effective to enhance germination percentage of L. tanakae. Regarding the temperature regime, $22^{\circ}C$ showed early germination of mistletoe seeds in vitro.

• Asian-Australasian Journal of Animal Sciences
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• v.13 no.11
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• pp.1593-1597
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• 2000

In the quiescent state, cattle-manure slurry stratifies into three discernible layers, namely a floating scum layer, a bottom sludge layer and a watery middle layer. The proportions of top (scum), middle and bottom (sludge) layers were approximately 20, 60 and 20% respectively of the volume of the whole slurry. Particulate matter from the different stratified layers was characterised for particle size distribution and cellulose, hemicellulose and lignin composition. Total solids concentrations of top, middle and bottom layers were 12.7, 2.8 and 7.4% respectively. Larger particles were found in the top layer compared with the bottom. The top layer contained the highest amounts of Neutral Detergent Fibre (NDF), Acid Detergent Fibre (ADF), cellulose and hemicellulose, but the lowest amount of Total Kjeldahl Nitrogen (TKN). The bottom layer contained the highest amounts of Acid Detergent Lignin (ADL) and TKN. With increase in particle size, there were increases in NDF, ADF, cellulose and hemicellulose, accompanied by decreases in ADL and TKN. Biochemical methane potential of the three layers was also measured. The top layer was found to produce the most methane with the middle layer producing the least. Biomethanation rate from the top layer was also the highest. Differences in biomethanation rates and biochemical methane potential were attributed to differences in chemical composition of the particulate matter. About 48%, 23% and 30% of the total chemical oxygen demand (COD) in the top, middle and bottom layers respectively of the slurry was found to be degradable.

• Journal of Plant Biology
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• v.16 no.3_4
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• pp.17-34
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• 1973

The physico-chemical factors, the distribution of chlorophyll and the primary production of the lakes Hwajinpo, Yongrangho, Chunchonho, Uiamho, Soyangho and Changjamot have been studied in order to make ecological comparison among these lakes during summer stagnation period of August to September of 1973. On the basis of the characteristics of these lakes, the lake types have been discussed. Thermocline is observed at 3-4m zone in the lake Changjamot and 4-5m zone in the lake Yongrangho. In the case of lake Hwajinpo and impoundments, the distinct thermal stratification is not observed at the summer stagnation period. As to vertical distribution of dissolved oxygen, a positive heterograde curve is obtained in the lakes Hwajinpo and Yongrangho. In the lake Changjamot the typical clinograde curve and the oxygen depletion in hypolimnion are observed. In the case of impoundments, however, the orthograde curve is observed in the lakes Chunchonho and Uiamho. While in the lake Soyangho, any stratification of the disssolved oxygen is not found. In the brackish lakes, such as lakes Hwajinpo and Yongragho, the salinity of hypolimnion is found to be much higher than that of epilimnion. In the lake Hwajinpo, the salinity of hypolimnion is exhibited 32.7$\textperthousand$, which is nearly the same as sea water. The distribution of nitrogenous compounds and phosphates is found to be high in the lake Changjmot. The silicate is also found in high concentration in the lake Chunchonho, and the distribution of nutrients in the brackish lakes is generally low. As to the vertical distribution of chlorophyll level, the lake Changjamot shows a stratum type and the brackish lakes L-type stratification. In the impoundments, lakes Chunchonho and Uiamho appear to be homogeneous type. Seasonal variation of chlorophyll level in the lake Changjamot is examined from January to September 1973. The vertical distribution of chlorophyll during the period of circulation from January to April is homogeneous type and is stratum type thereafter. The maximum chlorophyll level is 277.4mg/$m^2$ on June 23 and the pattern of seasonal variation of chlorophyll level is comparable to the type of eutrophy. The horizontal distribution of chlorophyll level is studied in the brackish lakes, Hwajinpo and Yongrangho. The pattern of distribution is found to be an irregular type. On the basis of measurements of primary production by means of the carbon-14 method and the distribution of chlorophyll level, it is concluded that the interior part of the lake Hwajinpo and Changjamot are eutrophic and the exterior part of the lake Hwajinpo, lake Yongrangho and the impoundments, lake Uiambo and Soyangho are mesotrophic.

• Proceedings of the KOSOMBE Conference
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• v.1995 no.11
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• pp.14-17
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• 1995

An in vitro construct of three dimensional artificial skin equivalent has been engineered using human cervical epithelial cells and human foreskin fibroblasts with a matrix of bovine type I collagen. Two cell lines were established from cervical uteri cancer tissues which have the HPV(human papillomavirus)18 genome. These two cell lines came from the same origin but have slight differencies in growth rate and tumorigenicity. The organotypic raft culturing of epithelial cells were accomplished at air-liquid interface. The differentiation related characteristics were examined by immunohistochemistry using monoclonal antibodies against EGFreceptor, cytokeratin 5/6/18 as proliferation markers and against filaggrin, involucrin, and cytokeratin 10/13 as differentiation marker. We have obtained the stratification and the differentiation in the artificial skin equivalent, and differentiation-related proteins were expressed more in the C3-artificial skin, and proteins of proliferation were expressed more in the C3N-artificial skin, relatively. We found that reconstituted artificial skin have the same characteristics of differentiation proteins of original tissue or cells of human body.

• Journal of Ginseng Research
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• v.6 no.1
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• pp.56-66
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• 1982

The effects of various dehiscent application such as dehiscent materials (big chaffs, vermiculite etc.), growth regulators and agricultural chemicals (plant protector.) on stimulation of dehiscence and shortening of dehiscent period were investigated Results obtained were as follows : 1. The moisture content of endosperm and seed coat at 10 day after dehiscent application amounts between 40% and 50%. 2. Endosperm diameter was increased with time of stratification, and the embryo growth showed in linear function, 3. Non-dehiscent seed showed also normally development of embryo, and the property of dehiscence dependent from physico-chemical nature of ginseng seed coat. 4. The best dehiscent materials were big chaffs and followed vermiculite, sand and sand with big chaffs. 5. The effect of dehiscence of ginseng seed showed higher activity in fungi than in bacteria in general. 6. Agricultural chemicals ( plant Protector) reduced the dehiscent rate of ginseng seed 7. The best timing of dehiscent treatment was between August 1 and August 10 but the smaller amount of dehiscent rate after August 10 dehiscent appllication indicated that big chaffs and growth regulator treatment may be controlled shortening of dehiscent period of ginseng seed.

• Nuclear Engineering and Technology
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• v.34 no.2
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• pp.105-116
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• 2002

In special industrial fields such 3s nuclear power plants and chemical plants, it is often necessary to repair system components without plant shutdown or drainage of system having many piping structures which may have hazardous or expensive fluid. A temporary ice plugging method for blocking internal flow is considered as a useful method in that case. According to the pipe freezing guideline of the nuclear power plant, the length of a freezing jacket must be longer than twice of the pipe diameter. However, for applying the ice plugging to short pipes which do not have enough freezing length because of geometrical configuration, it is inevitable to use shorter jacket less than twice of the pipe diameter. In this study, the integrity evaluation for short pipes in the nuclear power plant Is conducted by an experiment and the finite element analysis. From the results, the ice plugging process in short pipes can be safely carried out without any plastic deformation and fracture.

• Journal of Korean Society of Forest Science
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• v.38 no.1
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• pp.1-12
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• 1978

This study has intended to disclose the change of some chemical compositions of Ginkgo seeds which were acquired the treatment of cold-moist-stratification after collection. As check sample, the room-stored seeds were used. With the reasons that when the seeds not stratified were sown the delay of field germination has usually been resulted, the effectiveness of stratificaation in respect to alteration of chemical composition is to be investigated. The increase and decrease of growth promoting and inhibiting substances were investigated by means of chromatography method followed by rice seedling test or wheat coleoptile straight-growth test. The results obtained are summarized as follows; 1. In the untreated seeds, the zone of growth inhibitors on paper chromatograph were observed without regard to the tissue differences, embryo, endosperm and seedcoat. 2. Due to stratification, the amount of inhibitor has decreased in the embryo and seed coat, but growth promoters was decreased as compared with the check materials 3. The indications of results appear that each portion of the embryo, endosperm, and seedcoats of Ginkgo biloba L. contains the growth in hibitor taking part in germination dormancy. 4. It was presumed that hastening germination was influenced by decreasing of inhibitors in the embryo and seed coats rather than by increasing of promoters. 5. Gibberellin was detected at Rf 0.26 under the UV-lamp and the abscisic acid was detected at Rf 0.62, Rf 0.70, and Rf 0.78 and showed purple, gray, blue fluorescence respectively under the UV-lamp.