• Korean Journal of Fisheries and Aquatic Sciences
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• v.20 no.2
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• pp.95-105
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• 1987

Traditional sea Eel pots can be divided into two groups such as bamboo and plastic pots, however they are nearly same in a shape with one entrance and fishing efficiency, except their materials. Very few yet have been studied on their catching methods or catching mechanisms at the view point of behavior. Accordingly, we have designed tubular pots in order to fill up faults of traditional fishing gear construction and behaviors of sea eel. The suitable tubular pots was decided by comparative experiments in the water tank and the fishing efficiency was compared through the field experiments. The results obtained are as follows : 1. The differences between traditional plastic pots and improved tubular pots are firstly two entrances in both ends of tube without holes, secondly flapper nets are fixed at the end of each cone, and thirdly a bait bag is fixed at the center of pot. 2. The standard size of the suitable tubular pot is: $$Tube\;:\;\phi\;12\~13{\times}L80\;cm$$, $$Cone\;:\;Inside\;ring\;\phi6{\times}D5\;cm$$, Flapper : L10 cm. 3. The fishing efficiency of tubular rots is 2.3 times better than that of plastic pots.

• Microbiology and Biotechnology Letters
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• v.34 no.2
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• pp.94-100
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• 2006

To isolate a bacterium that produces plant growth promoting hormone, a total of 29 bacteria were obtained from the soil in Gyeongsan, Korea. Among these, 14 strains were selected by their positive reaction on Salkowski to produce auxin. All of these were then tested for their property to produce siderophore using CAS (chrome azurol S) blue agar, and one was chosen for its ability to produce both, auxin and siderophore. This strain, denoted, AHl8, showed 1.5 times higher adventitious root induction rates than controls, using mung-beans. The strain also showed efficient biocontrol properties towards Fusarium-wilt of tomatoes in artificial pot assays. The strain was identified as Bacillus subtilis by 16s rDNA comparison and Biolog analyses. Growth and media conditions for Bacillus subtilis AH1 8 to highly produce siderophore were also investigated.

• Journal of the Korean Dietetic Association
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• v.4 no.2
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• pp.132-144
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• 1998

The purpose of this study is setting proper portion by consumed size of food and food preference and then reducing plate wasts in school lunch. The survey was conducted from Oct. 21 to Nov. 22, 1996 through the practical measurement and questionnaires. The subjects were 43 students of 1 elementary school. The results of this survey was as follows : 1. Average consumption size of cooked rice was 115g. Average consumption size of one course dishes was 209g. The soup & pot stewes showed lower consumption rate than the other kind of foods. Average consumption size of fresh & boiled salad was 23.4g Average consumption size of stir fries was 55g. Average consumption size of steams & stewes was 42g. Most grill & fried foods showed high consumption rate compared to most of the other foods. Average consumption size of kimchies was 10.6g. The most of given desserts except apple were all consumed. 2. There was significant correlation between food preference and consumption rate for total food items. 3. Response of satisfaction about serving size of most of given foods except fresh & boiled salads, soup & pot stewes and kimchies were "moderate". 4. Visual estimation was greater than physical estimation for most of given foods. Proper portion of foods per person by results were setted as follows :

• The Korean Journal of Ecology
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• v.23 no.6
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• pp.445-452
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• 2000

The effects of sludge and fertilizer application on germination and seedling growth of woody plants on heavy metal mine tailings were evaluated by greenhouse experiment. Two different mine tailings (Lead-zinc mine tailings from Kwangmyong, Kyonggi-do and tungsten mine tailings from Sangdong. Kangwon-do). four fertilizer treatments (N +P +K: 20, 40, 60, and 80 kg/m$^3$), and four sewage sludge treatments (5.5, 11, 22.5, and 45 Mg/m$^3$) were used in the experiment. Tested plants were Pinus densiflora, Larix leptolepis, Amorpha fruticosa, and Alnus hirsuta. There were three replicates for each treatment. In addition, vermiculite was used instead of mine tailings to determine the effect of physical amendments. Fifty seeds of a species were sown in a pot (upper diameter 13.5 cm, depth 10 cm) and seedling emergence were recorded daily for 30 days. The highest germination rate was 53% for all treatments. Germination rate of Larix leptolepis was lowest among the four species studied. One month later after seeding, seedlings were thinned and only 5 seedling were left in each pot, and fertilizer and sewage sludge were applied once again. Growth of seedlings were determined for 10 weeks since then. Most plants grew very poorly or died within 5 weeks on lead/zinc mine tailings from Kwangmyong. The analysis of heavy metal contents by the total dissolution method showed that heavy metals generally increased in the order of tungsten mine tailings from Sangdong < sewage sludge from Puchon < lead/zinc mine tailings from Kwangmyong. Growth of woody plants was improved significantly by the fertilizer treatments on tungsten mine tailings. In contrast. survival and growth of woody plants were not affected significantly by the sewage sludge treatment on both tailings. This study shows that fertilizer applied to established seeded stands may provide some benefits in terms of increased ground cover in the field. It is suggested that reclamation should be proceeded by the study of the physico-chemical and biological characteristics of mine tailings.

• Journal of Ocean Engineering and Technology
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• v.33 no.3
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• pp.222-228
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• 2019

An extreme value analysis (EVA) is essential to obtain a design value for highly nonlinear variables such as long-term environmental data for wind and waves, and slamming or sloshing impact pressures. According to the extreme value theory (EVT), the extreme value distribution is derived by multiplying the initial cumulative distribution functions for independent and identically distributed (IID) random variables. However, in the position mooring of DNVGL, the sampled global maxima of the mooring line tension are assumed to be IID stochastic variables without checking their independence. The ITTC Recommended Procedures and Guidelines for Sloshing Model Tests never deal with the independence of the sampling data. Hence, a design value estimated without the IID check would be under- or over-estimated because of considering observations far away from a Weibull or generalized Pareto distribution (GPD) as outliers. In this study, the IID sampling data are first checked in an EVA. With no IID random variables, an automatic resampling scheme is recommended using the block maxima approach for a generalized extreme value (GEV) distribution and peaks-over-threshold (POT) approach for a GPD. A partial autocorrelation function (PACF) is used to check the IID variables. In this study, only one 5 h sample of sloshing test results was used for a feasibility study of the resampling IID variables approach. Based on this study, the resampling IID variables may reduce the number of outliers, and the statistically more appropriate design value could be achieved with independent samples.

• Journal of Korean Society of Forest Science
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• v.95 no.6
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• pp.735-742
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• 2006

The objective of this study was to elucidate the tolerance of woody plants to simulated acid rain in relation to mycorrhizal inoculation. Germinating seedlings of Robinia pseudoacacia were planted in 1I pots with autoclaved soil mixture of vermiculite, sand and nursery soil at 1:1:1 ratio. Each pot was inoculated with both crushed root nodules from a wild tree of the same species and commercial arbuscular mycorrhizal inoculum of Glomus intraradices at the time of planting the seedlings. Simulated acid rains at pH 2.6, 3.6, 4.6, and 5.6 were made by mixing sulfuric acid and nitric acid at 3: 1 ratio. Each pot received nutrient solution without N and P, and was also supplied with 180 ml of the one pH level of the acid rains once a week for 50 days. The plants were grown in the green house. At the end of experimental period, plants were harvested to determine contents of chlorophyll, mineral nutrients and net photosynthesis in the tissues, dry weight of the plants, and mycorrhizal infection in the roots. Mycorrhizal infection rate was significantly reduced only at pH 2.6, which meant vitality of G intraradices was inhibited at extremely low pH. Height growth, dry weight production, nodule production and chlorophyll content were increased by mycorrhizal infection in all the pH levels except pH 3.6. Particularly, mycorrhizal inoculation increased root nodule production by 85% in pH 5.6 and 45% in 4.6 treatments. But the stimulatory effect of mycorrhizal inoculation on nodule production was reduced at pH 3.6 and 2.6. Net photosynthesis was increased by mycorrhizal infection in all the pH levels. The phosphorus(P) content in the tissues was increased by 43% in average by mycorrhizal inoculation, which was statistically significant except in pH 2.6. It was concluded that mycorrhizal inoculation of Robinia pseudoacacia would enhance growth and resistance of the plants to acid rain by improving the photosynthesis, phosphorus nutrition, and more nodule production.

• Korean journal of applied entomology
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• v.45 no.2 s.143
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• pp.201-209
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• 2006

Five strains of Korean entomopathogenic nematodes (EPN), steinernematids and heterorhabditids were evaluated and tried in laboratory, pot, and vegetable greenhouses for environmentally friendly control of diamondback moth (DBM), Plutella xyiostella, from 2002 to 2005. LC$_{50}$ values of five EPN strains against DBM were different depending on nematode strain and DBM instar. LC$_{50}$ value of Steinernema carpocapsae GSN1 (GSN1) was the lowest representing 2.6$\sim$3.9 infective juveniles (Ijs, 3rd stage) to 2nd to 4th instars of DBM. Pathogenicity of five effective strains against DBM was different depending on nematode strain, concentration, application times, and vegetable in pot. The most effective nematode was GSN1. Steinernema spp. was more effective than Heterorhabditis spp. against DBM. Two or three times of applications of EPN were effective regardless of nematode strain and concentration in pot. Efficacy of EPN was different depending on vegetable species. Efficacy was higher on Chinese cabbage, red mustard, and Ssamchoo than that on cabbage, kale, and leaf broccoli. Efficacy of GSN1, Steinernema GSNUS-10, Steinernema CSNUS-14, and Heterorhabditis GSNUH-1 was variable depending on nematode strain, concentration, application times, and vegetable in greenhouse experiments. GSN1 was the most effective and 100,000 infective juveniles per m$^2$(=$1\times10^9$ Ijs/ha) resulted in higher efficacy. Three times of application of nematodes led to higher control efficacy than one or two applications. Efficacy of nematodes was higher on Chinese cabbage than cabbage or kale in greenhouse.

• Economic and Environmental Geology
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• v.35 no.3
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• pp.257-271
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• 2002

One of the main interests in relation to heavily contaminated gully-pot sediment in urban area is the short term mobility of heavy metals, which depends on the pH of acidic rainwater and on the buffering effects of carbonate minerals. The buffering effects of carbonates are determined by titration (acid addition). Leaching experiments are carried out in solutions with variable initial HN03 contents for 24h. The gully-pot sediment appears to be predominantly buffered by calcite and dolomite. In case of sediment samples, which highly contain carbonates, pH decreases more slowly with increasing acidity. On the other hand, for the sediment samples, which less contain carbonate minerals, pH rapidly drops until it reaches about 2 then it decreases slowly. The leaching reactions are delayed until more acid is added to compensate for the buffering effects of carbonates. The Zn, Cu, Pb and Mn concentrations of leachate rapidly increase with decreased pH, while Cd, Co, Ni, Cr and Fe dissolutions are very slow and limited. The solubility of heavy metals depends not only on thc pH values of leachatc but also on the speciation in which metals are associated with sediment particles. In slightly to moderately acid conditions, Zn, Cd, Co, Ni and Cu dissolutions become increasingly important. As deduced from leaching runs, the relative mobility of heavy metals at pH of 5 is found to be: Zn > Cd > Co > Ni > Cu » Pb > Cr, suggesting that moderately acid rainwater leach Zn, Cd, Co, Ni and Cu from thc contaminated gully-pot sediment, while Pb and Cr would remain fixed. The buffering effects of Ca- and Mg-carbonates play an important role in delaying as well as limiting the leaching reactions of heavy metals from highly contaminated gully-pot sediment. The extent of such a secondary environmental pollution will thus depends on how well the metals in sediment can be leached by somewhat acidic rain water. Changes in the physicochemical environments may result in the severe environmental pollution of heavy metals. These results are to be taken into account in the management of contaminated sediments during rainstorms.

• Korean Journal of Heritage: History & Science
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• v.53 no.2
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• pp.4-23
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• 2020

The purpose of this study was to explore the diversity of Korea's iron casting technology and to examine various casting methods. The study involved a literature review, analysis of artifacts, local investigation of production tools and technology, and scientific analysis of casting and cast materials. Bellows technology, or Bulmi technology, is a form of iron casting technology that uses bellows to melt cast iron before the molten iron is poured into a clay cast. This technology, handed down only in Jeju Island, relies on use of a clay cast instead of the sand cast that is more common in mainland Korea. Casting methods for cast iron pots can be broadly divided into two: sand mold casting and porcelain casting. The former uses a sand cast made from mixing seokbire (clay mixed with soft stones), sand and clay, while the latter uses a clay cast, formed by mixing clay with rice straw and reed. The five steps in the sand mold casting method for iron pot are cast making, filling, melting iron into molten iron, pouring the molten iron into the cast mold, and refining the final product. The six steps in the porcelain clay casting method are cast making, cast firing, spreading jilmeok, melting iron into molten iron, pouring the molten iron, and refining the final product. The two casting methods differ in terms of materials, cast firing, and spreading of jilmeok. This study provided insight into Korea's unique iron casting technology by examining the scientific principles behind the materials and tools used in each stage of iron pot casting: collecting and kneading mud, producing a cast, biscuit firing, hwajeokmosal (building sand on the heated cast) and spreading jilmeok, drying and biyaljil (spreading jilmeok evenly on the cast), hapjang (combining two half-sized casts to make one complete cast), producing a smelting furnace, roasting twice, smelting, pouring molten iron into a cast, and refining the final product. Scientific analysis of the final product and materials involved in porcelain clay casting showed that the main components were mud and sand (SiO₂, Al₂O₃, and Fe₂O₃). The release agent was found to be graphite, containing SiO₂, Al₂O₃, Fe₂O₃, and K₂O. The completed cast iron pot had the structure of white cast iron, comprised of cementite (Fe₃C) and pearlite (a layered structure of ferrite and cementite).

• Korean Journal of Soil Science and Fertilizer
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• v.1 no.1
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• pp.27-41
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• 1968

In order to clarify the effect of various forms or phosphate on the production of paddy in Korea and to find out the superiority of any form, a number of field and pot experiments involving various phosphate fertilizers were carried out in addition to conducting one each of sand culture and soil culture pot experiments in 1963 and 1964. The results of these studies are summarized as follows: 1. In sand culture experiment, the best effect of a phosphate fertilizer was obtained with the mono-calcium phosphate which is soluble in water, followed by citric acid soluble phosphate such as fused phosphate and di-calicum phosphate. However, in the pot culture and field experiments, fused phosphate had shown it's superiority than triple superphosphate which contains water soluble form of phosphate followed by hypo phosphate, roasted phosphate, compound fertilizer, and slag phosphate. The effect of rock phosphate was the least in most cases. 2. The superiority of fused phosphate to triple super phosphate in soil culture was supposed to be: a) The fused phosphate can neutralize the soil acidity. b) The fused phosphate can supply magnesium and magnesium lead to the balanced conditions of exchangeable bases in soils. c) The magnesium in the fused phosphate helps the transportation of phosphate, and regulate the absorption of the element.