• The Journal of the Convergence on Culture Technology
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• v.6 no.3
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• pp.193-204
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• 2020

According to science technology development, information society has progressed rapidly in the 21st century. Our consciousness and tradition have become entangled in the tide of Westernization. Therefore, the education of Chinese characters was neglected, and Chinese poetry literature was naturally neglected. This led to the abundance of material civilization, however, from the mental aspects, the daily life of modern people became insecure. There is a poet who has lived a lonely life of creation of Chinese poetry in this era. He is a Geasan Kwon Seung Geun(1940~) who writes only poem while being friends with nature. His Chinese poems were revealed through life experiences in nature, which is inspiring sympathy. The origin of his theme is nature. The poetry obtained from nature is rustic simple and pure. Therefore His poems have the style and taste of nature. The Chinese poetry literature of Geasan has been embodied the elements of self-interest, self-satisfaction, self-contentment and living in free at his literatue. On its basis, his Chinese literature has aesthetic boundary of remaining aloofness(自然而然的 超然)·rambling talk, living peacfully and play around with leisure·(閒遠物遊的 閑淡)·deviation rhyme of vividly and beautifully(生趣淸遠的 逸韻) The aesthetic boundary of Chinese poetry of Geasan can be seen as having a depth. This is the aesthetic boundary of Chinese poetry written by this generation in the 21st century.

• Applied Chemistry for Engineering
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• v.16 no.6
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• pp.809-814
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• 2005

In this work, the thermal properties of epoxy coating system on the liner plate in the containment structure of nuclear power plants had been examined by irradiation and design basis accident (DBA) conditions. The effect of immersion in hot water on adhesion strength of the coating system had been also studied. The glass transition temperature ($T_g$) and thermal stability of ET-5290/carbon steel A 32 epoxy coating systems were measured by DSC and TGA analyses, respectively. Contact angle measurements were used to determine the effect of immersion on the surface energetics of epoxy coating system, with a viewpoint of surface free energy. Adhesion tests were also executed to evaluate the adhesion strength at interfaces between carbon steel plate and epoxy resins. As a result, it was found that the irradiation led to an improvement of internal crosslinked structure in cured epoxy systems, resulting in significantly increasing the thermal stability, as well as the $T_g$. Also, the immersion in hot water made a role in the post-curing of epoxy resins and increased the mechanical interlocking of the network system, resulting in increasing the adhesion strength of the epoxy coating system.

• Korean Journal of Food Science and Technology
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• v.44 no.5
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• pp.613-620
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• 2012

This study was carried out to investigate changes in nutrient composition and fermentation properties in abalone mul-kimchi using dried pollack stock (AMKP) and licorice stock (AMKL) during storage at $4^{\circ}C$ for 35 days. The levels of moisture (88.37-90.94%) and crude ash (2%) did not differ much between AMKP and AMKL during the 35 days of storage. But crude protein and crude lipid levels decreased gradually until 21 days of storage. AMKP and AMKL fermentation during 21 days led to a decrease in pH, increased acidity, and the highest Leuconostoc sp. count. AMKP and AMKL showed acidity of 0.50% at pH 4.30, when the kimchi samples were ripened properly. Glutamic acid showed the highest content in AMKP and AMKL, and hydroxypoline was the most abundant of all free amino acids. We have provided basic data for commodification research on abalone mul-kimchi.

• Journal of the Korean Wood Science and Technology
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• v.44 no.1
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• pp.124-134
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• 2016

The main goal of this study was to investigate biomodification mechanism of lignin by white rot fungus, Abortiporus biennis, and to depolymerize ethanol organosolv lignin for industrial application. In nitrogen-limited culture, A. biennis polymerized mainly lignin showing a rapid increase of molecular weight and structural changes depending on incubation days. At the initial incubation days, cleavage of ether bonds increased phenolic OH content, while the results were contrary in of the later part of the culture. Based on these results, ascorbic acid as a reducing agent was used to induce depolymerization of lignin during cultivation with white rot fungus. As a result, the degree of increase of average molecular weight of lignin was significantly declined when compared with those of the ascorbic acid free-experiment, although the molecular weight of fungus treated sample slightly increased than that of control. Furthermore, lignin derived oligomers in culture medium were depolymerized with the addition of ascorbic acid, showing that the average molecular weight was 381 Da, and phenolic OH content was 38.63%. These depolymerized lignin oligomers were considered to be applicable for industrial utilization of lignin. In conclusion, A. biennis led to the polymerization of lignin during biomodification period. The addition of ascorbic acid had a positive effect on the depolymerization and increase of phenolic OH content of lignin oligomers in medium.

• Journal of the Korean Applied Science and Technology
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• v.36 no.4
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• pp.1259-1267
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• 2019

Anti-inflammatory and anti-oxidative activities were examined on the extract of Dendranthema indicum (D. indicum) flowers. The flowers were extracted two times for 24 h each with 70% ethanol. Upon the biological activities screening, the ethanol extract exhibited potent free radical scavenging activities and inhibited the production of nitric oxide on LPS-induced RAW264.7 macrophages effectively without causing cell toxicity. Further purification by medium pressure liquid hromatography (MPLC) and identification of the isolates led to identification of cynaroside (1) and apigetrin (2). The chemical structures of the isolated compounds were elucidated based on spectroscopic data including nuclear magnetic resonance (NMR) spectra, as well as comparison of the data to the literature values. Also, the quantitative analysis of the compounds was perfromed by high-performance liquid chromatography (HPLC). The isolates 1 and 2 were determined to inhibite the nitric oxide (NO) production dose-dependently. Based on these results, it was suggested that D. indicum extract could be useful as anti-inflammatory agents in cosmetics applications.

• Korean Chemical Engineering Research
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• v.43 no.5
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• pp.632-636
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• 2005

In this work, the effect of chemical treatments on surface properties of SiC was investigated in thermal and mechanical interfacial behaviors of SiC/PMMA nanocomposites. The acid/base value, contact angles, and FT-IR analysis were performed for the study of surface characteristics of the SiC studied. The thermal stabilities of the SiC/PMMA nanocomposites were investigated by thermogravimetric analysis (TGA). Also the mechanical interfacial properties of the composites were studied in critical stress intensity factor ($K_{IC}$) and critical strain energy release rate ($G_{IC}$) measurements. As a result, the acidically treated SiC (A-SiC) had higher acid value than that of untreated SiC (V-SiC) or basically treated SiC (B-SiC). The acidic solution treatment led to an increase in surface free energy of the SiC, mainly due to the increase of its specific component. Thermal and mechanical interfacial properties of the SiC/PMMA nanocomposites, including initial decomposition temperature (IDT), $K_{IC}$, and $G_{IC}$ had been improved in the acidic treatment on SiC. This was due to the improvement in the interfacial bonding strength, resulting from the acid-base interfacial interactions between the fillers and polymeric matrix.

• Journal of the Korean Applied Science and Technology
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• v.31 no.4
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• pp.595-601
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• 2014

The microstructures of NATM were examined by SEM, FT-IR spectra, tensile properties, mole % of [NCO/OH], and particle size analyzer. Growing concerns in the environment-friendly industries have led to the development of solvent-free formulations that can be cured. We had synthesized NATM(New Austria Tunnel Method) resin having the ability to protect stainless steel against corrosion. Comparing with general NATM resin and coatings, this resin that synthesized with polyurethane and epoxy was highly stronger in intensity and longer durability. Hybrid resin was composed of polyols, MDI, epoxy, silicone surfactant, catalyst and crosslink agent, and fillers. Moreover, fillers such as fume silica not only accelerated the curing rate but also improved the physical property as thermal barriers. The rigid segments of synthetic resin in mechanical properties were due to fume silica and the increase the mole% of [NCO/OH] for corrosion protection. In conclusion, the hybrid resin microstructure with crosslink agent and fume silica are good material for thermosetting coating of metal substrates such as stainless steel.

• Macromolecular Research
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• v.17 no.8
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• pp.616-622
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• 2009

In-depth understanding of the influence of hot pressing and melt processing on the properties of thermoplastic polyurethane (TPU) is critical for effective mechanical recycling of TPU scraps. Therefore, this study focused on the effects of hot pressing and melt mixing on molecular weight (MW), polydispersity index (PDI), melt index (MI), characteristic IR peaks, hardness, thermal degradation and mechanical properties of TPU. The original TPU pellet (o-TPU) showed two broad peaks at lower and higher MW regions. However, four TPU film samples, TPU-0 prepared only by hot pressing of o-TPU pellet and TPU-1, TPU-2 and TPU-3 obtained by hot pressing of melt mixed TPUs (where the numbers indicate the run number of melt mixing), exhibited only a single peak at higher MW region. The TPU-0 film sample had the highest $M_n$ and the lowest PDI and hardness. The TPU-1 film sample had the highest $M_w$ and tensile modulus. As the run number of melt mixing increased, the peak-intensity of hydrogen bonded C=O stretching increased, however, the free C=O peak intensity, tensile strength/elongation at break and average MW decreased. All the samples showed two stage degradations. The degradation temperatures of TPU-0 sample (359 $^{\circ}C$ and 394 $^{\circ}C$)were higher than those of o-TPU (342 $^{\circ}C$ and 391 $^{\circ}C$). While all the melt mixed samples degraded at almost the same temperature (365 $^{\circ}C$ and 381 $^{\circ}C$). The first round of hot pressing and melt mixing was found to be the critical condition which led to the significant changes of $M_n$/$M_w$/PDI, MI, mechanical property and thermal degradation of TPU.

• Journal of Navigation and Port Research
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• v.42 no.6
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• pp.459-468
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• 2018

Deep-sea fishing vessel No. 501 Oryong was fully flooded through its openings and sank to the bottom of the Bering Sea. The tragic accident was attributed to rough sea weather after a fishing operation in the Bering Sea, and led to the death or loss of many crewmen. In this study, the ship stability calculation was carried out using KST-SHIP (ship calculation system of KST), considering the free surface effect and fish catch arrangement according to the progress of its sinking accident, and stability after flooding was analyzed. The calculation results obtained using KST-SHIP were verified by comparing them to intact stability calculation sheet of the accident ship under the full load departure condition, and intact stability according to displacement from the departure of accident ship up to the moment of the accident was calculated and analyzed. The stability after flooding was also calculated and analyzed according to the progress during its sinking accident.

• The Journal of the Convergence on Culture Technology
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• v.10 no.4
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• pp.357-365
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• 2024

The purpose of this study is to investigate the effects of children's robot-based play on sequential thinking through appreciation of picture books. For this purpose, 15 children aged 5 years old in each kindergarten located in Seoul were selected and J kindergarten (experimental group) supported <Picture book appreciation robot play> and C kindergarten (comparison group) supported <Picture book appreciation free play>. In order to examine the difference in play experience between the two groups, the score data before and after play support was collected using the sequential thinking test tool, and the collected data were analyzed using SPSS 28.0 program to perform ANCOVA (Covariance Analysis). As a result, the experimental group that experienced robot-based play through picture book appreciation showed significant improvement in the total score of sequential thinking and the sub-areas of dynamics, behavior, and intention compared to the control group.The results of this study are valuable as a play study to discover the value of robots as a creative play medium led by young children and to promote sequential thinking ability, which is emphasized as the capacity of future society.