• Korean Journal of Soil Science and Fertilizer
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• v.33 no.3
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• pp.160-166
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• 2000

The reasonable level of nitrogen fertilizer of Gyokuro tea which is producted fresh leaves plucked from shade tea plants is a key factor to increase crop yield and quality. Nitrogen were applied at the level to 60, 80, 100 and $120kg\;10a^{-1}$. Analytical results of yield and quality of Gyokuro tea are summarized as follows : The soil fertility of experimental field was higher in organic matter($59.8g\;kg^{-1}$) and available phosphate($1,285mg\;kg^{-1}$), but lower in pH(4.79) compared to the common field. As the amount of nitrogen fertilizer application was increased to $80kg\;10a^{-1}$, the yield of tea leaves, the content of total nitrogen, total amino acid, caffeine and chlorophyll were increased. However, the yield of tea leaves was not increased above $100kg\;10a^{-1}$ and the increased level of nitrogen fertilizer did not show any different in the content of tannin and vitamin C. When the amount of nitrogen fertilizer application was raised, the content of thiamine and arginine increased, but the content of aspartic acid, serine and glutamic acid decreased. The content of fatty acid was produced $2.850{\sim}3.012mg\;100g^{-1}$ Especially, the content of oleic acid, linoleic acid and linolenic acid was higher at the level of $80kg\;10a^{-1}$ application than other treatments. As nitrogen was applied at $80kg\;10a^{-1}$, sensory score was 0.2~4.6 point higher than other treatments. Consequently, $80kg\;10a^{-1}$ is considered to be the best level of nitrogen fertilizer both quality and crop yield.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.6
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• pp.1035-1041
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• 2011

Salinity of soil under the plastic film houses in Korea is known as a significant factor to lower the crop production and to hamper the sustainable agricultural land management. In this study we propose a field monitoring technique to examine the methods applied to minimize the adverse effect of salts in soil based on the relationship between soil electrical characteristics and soil properties. Field experiments for 4 different treatments (water only, fertilizer only, DTPA only, and DTPA and fertilizer together) were conducted on soils at the plastic film house built for cultivating a cucumber plant located at Chunan-si, Chungchungnam-do in Korea. The electrical resistivity was measured by both a dipole-dipole and wenner multi-electrodes array method. After the electrical resistivity measurement we also measured the soil water content, temperature, and electrical conductivity on surface soil. The resulted image of the interpreted resistivity by the inversion technique presented a unique spatial distribution depending on the treatment, implying the effect of the different chemical components. It was also highly suspected that resistivity response changed with the nutrients level, suggesting that our proposed technique could be the effective tool for the monitoring soil water as well as nutrient during the cropping period. Especially, subsoils under DTPA treatment at 40 to 60 cm depth typically presented lower soil water accumulation comparing to subsoils under non-DTPA treatment. It is considered that DTPA resulted in increase of a root water uptake. However, our demonstrated results were mainly based on qualitative comparison. Further experiments need to be conducted to monitor temporal changes of electrical resistivity using time lapse analysis, providing that a plant root activity difference based on changes of soil water and nutrients level in time.

• Fire Science and Engineering
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• v.33 no.2
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• pp.1-8
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• 2019

This study was conducted to investigate the possibility of spontaneous ignition in Butadiene popcorn polymer, which is used as raw material and product in a chemical plant. A component analysis, thermogravimetric analysis, thermal stability analysis, spontaneous ignition point measurement and accelerated velocity calorimetric analysis were performed. As a result of analysis, various kinds of flammable components were measured and thermogravimetric analysis showed a weight loss of 95.6% in air and 89.2% in nitrogen. As a result of the thermal stability analysis, heat generation started at $88^{\circ}C$ in the air atmosphere, and the heat generation rate increased sharply in the vicinity of the natural ignition point ($220^{\circ}C$). The heat generation started at about $70^{\circ}C$ in nitrogen atmosphere, and the two exothermic peak values were observed up to $450^{\circ}C$. As a result of accelerated rate calorimetry, there was no exothermic phenomenon, and the lowest ignition temperature was $211.7^{\circ}C$ as a result of analysis of natural ignition point. Based on the results obtained from the thermal stability evaluation, it is considered that the possibility of inducing the thermal deformation of the column by the heat of reaction is sufficient.

• Journal of Life Science
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• v.28 no.12
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• pp.1523-1528
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• 2018

This study investigated the chemical composition of four Korean cultivated Chrysanthemum indicum L. (Gamguk 1 ho, Gamguk 2 ho, Gamguk 3 ho, and Wonhyang) which are used in the food and fragrance industries to identify their volatile flavor compounds. These compounds were analyzed using headspace GC-MS from plant samples cultivated in the same region of Korea (Sancheong-gun, Gyeongsangnam-do). A total of 23 compounds were identified, eight of which were common across the four cultivars. The major flavor components in the three Gamguk plants were identified as 3-carene, camphene, ${\beta}$-phellandrene, eucalyptol and (+)-camphor. Eleven compounds, including (+)-camphor at 31.40%, were identified in Gamguk 1 ho. Gamguk 2 ho was found to contain 12 flavor compounds, predominant of which was camphene at 25.60%. Thirteen compounds including (+)-camphor (26.88%) were identified in Gamguk 3 ho, while 17 were detected in the Wonhyang cultivar, including trans-piperitol (47.33%), sabinene, and ${\gamma}$-terpinyl acetate. These results indicate differences in the type and ratio of functional volatile flavor ingredients in Chrysanthemum indicum L. cultivars which is highly valuable as material for fragrance product development.

• Journal of Mushroom
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• v.17 no.1
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• pp.24-33
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• 2019

The physicochemical characteristics of oyster mushrooms (Pleurotus ostreatus) cultivated using liquid spawn (MLS) were compared with those of commercial mushrooms cultivated using solid spawn. The color intensity of the two types of mushrooms showed no remarkable difference. The hardness of the MLS-cultivated mushrooms was significantly higher, but their moisture content (86.80%) was significantly lower than that of the commercial mushrooms. Mineral contents in MLS-cultivated mushrooms (421.17 mg/100 g) were significantly higher than those in the commercial mushrooms (333.26-362.78 mg/100 g); in particular, the potassium (K) content was the most abundant in the former. The amino acid content in the MLS-cultivated mushrooms (4,695.22 mg/100 g) was about 1.4-2.0 times that in the commercial mushrooms. The essential amino acid contents and sum of aspartic acid and glutamic acid were higher in the MLS-cultivated mushrooms than in the commercial mushrooms. The ${\beta}-glucan$ content in the MLS-cultivated mushrooms was 1.1-2.3 times higher than that in the commercial mushrooms. The total phenol and flavonoid contents and the DPPH and ABTS radical-scavenging activities of the MLS-cultivated mushrooms were significantly higher than those of the commercial mushrooms; however, the reducing power showed an opposite trend. Therefore, MLS-cultivated mushrooms contained higher amounts of valuable components and higher antioxidant activities than commercial mushrooms.

• Toxicological Research
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• v.35 no.4
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• pp.361-369
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• 2019

1,2-Dichloropropane (1,2-DCP) has been used as an industrial solvent and a chemical intermediate, as well as in soil fumigants. Human exposure may occur during its production and industrial use. The target organs of 1,2-DCP are the eyes, respiratory system, liver, kidneys, central nervous system, and skin. Repeated or prolonged contact may cause skin sensitization. In this study, 1,2-DCP was dissolved in corn oil at 0, 2.73, 5.75, and 8.75 mL/kg. The skin of mice treated with 1,2-DCP was investigated using western blotting, hematoxylin and eosin staining, and immunohistochemistry. 1,2-DCP was applied to the dorsal skin and both ears of C57BL/6J mice. The thickness of ears and the epidermis increased significantly following treatment, and the appearance of blood vessels was observed in the dorsal skin. Additionally, the expression of vascular endothelial growth factor, which is tightly associated with neovascularization, increased significantly. The levels of protein kinase-B (PKB), phosphorylated PKB, mammalian target of rapamycin (mTOR), and phosphorylated mTOR, all of which are key components of the phosphoinositide 3-kinase/PKB/mTOR signaling pathway, were also enhanced. Taken together, 1,2-DCP induced angiogenesis in dermatitis through the PI3K/PKB/mTOR pathway in the skin.

• Journal of Conservation Science
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• v.37 no.2
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• pp.154-166
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• 2021

The royal seal, in either gold or jade, is used to symbolize Joseon's royal family, and it is made up of a Bonu (a handle), Bosin (a body), Bomun (a letter inscribed on the seal), and Bosu (a string attached to the seal). The Bosu was designed to enhance the seal's dignity and facilitate convenient handling. Bosu consists of Kkeun-mog and Bangwool-sul (decorated with gilt paper), which are made of Bangwool, Bangwool-mog, and Sul. In this study, the form survey, color, material, and composition of 318 Bosu pieces from the Joseon Dynasty and Korean Empire produced from 1441 to 1928 were analyzed. As time passed, the strings on the seals became longer and thinner. Bangwool-mog disappeared from the mid-1800s, and a ring appeared at the end of the Sul. Most of the colors used were scarlet, but orange and purple were also identified. Although most of the Bosu are silk, five Bosu from the 1900s and one Bosu from the 1740s (likely replaced in the 1900s) are estimated to be rayon. The gilt paper's main chemical components used to decorate the Bangwool-sul vary according to age. Until the mid-1800s, gold (Au) was used for the Sul and Bangwool, but since the mid-1800s, gold (Au) and brass (Cu-Zn) were used for Sul and Bangwool, respectively, and then brass (Cu-Zn) was used for Sul and Bangwool. While the Bosu was a seal accessory, it can be used to identify changes in the manufacturing techniques and materials of the period.

• Clean Technology
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• v.27 no.2
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• pp.160-167
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• 2021

This study investigated the environmental effects of improving the general-type activated carbon adsorption tower used at the Sihwa/Banwol Industrial Complex with use of a cartridge-type activated carbon adsorption tower for the application of an activated carbon co-regenerated system. Four general-type activated carbon adsorption towers and two cartridge-type activated carbon adsorption towers were selected to analyze the properties of activated carbon and to compare the efficiency of reducing environmental pollutants. The results showed that the activated carbon used in the cartridge-type activated carbon adsorption towers was high quality activated carbon with an iodine adsorption force of more than 800 mg/g and that a good adsorption performance was maintained within the replacement cycle. From an analysis of the environmental pollutant reduction efficiency, it was confirmed that the cartridge-type activated carbon adsorption tower functioned properly as a prevention facility for handling emissions pollutants with a treatment efficiency of total hydrocarbons (THC), toluene, and methylethylketone (MEK) components of 71%, 77%, and 80%, respectively. The general activated carbon adsorption tower, which was confirmed to use low-performance activated carbon, had a very low treatment efficiency and did not function properly as a prevention facility for dealing with emission pollutants. It is believed that it is possible to reduce pollutants during operations by changing from the general-type activated carbon adsorption tower to a cartridge-type activated carbon adsorption tower.

• Applied Chemistry for Engineering
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• v.32 no.4
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• pp.409-416
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• 2021

Dimensionally stable electrodes are one of the important components in electrochemical water treatment processes. In the manufacturing of the dimensionally stable electrodes, the type of metal catalyst coated on the surface of the metal substrate, the coating and sintering methods substantially influence their performance and durability. In this study, using Ir-Ru-Ta ternary metal coating, various electrodes were prepared depending on the coating method under the same pre-treatment and sintering conditions, and its performance and durability were studied. As a coating method, brush and spray coating were used. As a result, the reduction in the amount of catalyst ink was achieved because more amount of metal could be coated for the electrode using spraying with the same amount of catalyst ink. In addition, the spray_2.0_3.0 electrode prepared by a specific spray coating method shows the phenomenon of cracking and the uniform coating of the ternary metal on the surface of the coating layer, and results in a high electrochemically active specific surface area, and the decomposition performance of 4-chlorophenol was superior to the other electrodes. However, it was found that there was no significant difference in durability depending on the coating method.

• Applied Chemistry for Engineering
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• v.32 no.3
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• pp.332-339
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• 2021

Recently, due to concerns about the depletion of fossil fuels and the emission of greenhouse gases, the importance of hydrogen energy technology, which is a clean energy source that does not emit greenhouse gases, is being emphasized. Water electrolysis technology is a green hydrogen technology that obtains hydrogen by electrolyzing water and is attracting attention as one of the ultimate clean future energy resources. In this study, the surface properties of the porous transport layer (PTL), one of the cell components of the proton exchange membrane water electrolysis (PEMWE), were controlled using a sandpaper to reduce overvoltage and increase performance and stability. The surfaces of PTL were sanded using sandpapers of 400, 180, and 100 grit, and then all samples were finally treated with the sandpaper of 1000 grit. The prepared PTL was analyzed for the degree of hydrophilicity by measuring the water contact angle, and the surface shape was observed through SEM analysis. In order to analyze the electrochemical characteristics, I-V performance curves and impedance measurements were conducted.