• Journal of Industrial and Engineering Chemistry
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• v.67
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• pp.276-283
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• 2018

For the first time, polyvinyl chloride (PVC) was used as an easily-handled chlorine source for preparation of isotropic pitch-based carbon fiber (IPCF) incorporating ethylene bottom oil (EO) as a raw material. Pitch precursors were prepared by the chlorination-dehydrochlorination triggered by chlorine radicals originated from PVC; aromatization and poly-condensation reactions occurred by polyene-type radicals from PVC. Radical production and co-carbonization were facilitated by pretreatments of EO through vacuum distillation, bromination, and additional heat treatment. Pitches were prepared by the co-carbonization of pretreated EO and EO containing 20 wt% PVC, and had higher yields and better spinnability than those by simple distillation.

• New & Renewable Energy
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• v.7 no.1
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• pp.36-44
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• 2011

Technology is developed from the efficient interaction with other technology files while building up its own research field. This study analyzes the structure of solar cell research area and describes its paths of the technology development in terms of interdisciplinary diversity using the Co-Classification method during 1979-2009. As a results, 1,380 studies are determined as the interdisciplinary among the 2,605 studies. It shows that 52.98% of the solar cell researches have interdisciplinary relationships with two or more research fields. In addition, we show that the research area of solar cell technology is composed by Material Science, Multidisciplinary and Energy & Fuel, Physics, Applied, Chemistry, Physical from the Co-Classification matrix and network analysis. It means the complexity of the technological knowledge production increased with the concept of interdisciplinary. The results can be used for the planning of the efficient solar cell technology development.

• Journal of the Korean Magnetics Society
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• v.5 no.5
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• pp.690-694
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• 1995

Reducing media noise is a key to realizing high areal recording density. However, perpendicularly oriented Co-Cr films, stong candidates for high density recording media, have received little attention in terms of recording noise. We studied the noise characteristics of Co-Cr based alloy films by varying the compositionally separated structure. Co-Cr films with fine compositionally separated microstructure were observed to have low noise, which recording density dependence were negative or week. Studies on control of the microstructure and magnetic properties in combination with noise analysis are important to realize high density recording media.

• Journal of Industrial and Engineering Chemistry
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• v.67
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• pp.358-364
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• 2018

An isotropic pitch precursor for fabricating carbon fibres was prepared by co-carbonization of ethylene bottom oil(EBO) and polyvinyl chloride (PVC). Various pre-treatments of EBO and PVC, and a high heating rate of $3^{\circ}C/min$ with no holding time, were evaluated for their effects on the oxidative stabilization process and the mechanical stability of the resulting fibres. Our stabilization process enhanced the volatilization, oxidative reaction and decomposition properties of the precursor pitch, while the addition of PVC both decreased the onset time and accelerated the oxidative reaction. Aliphatic carbon groups played a critical role in stabilization. Microstructural characterization indicated that these were first oxidised to carbon-oxygen single bonds and then converted to carbon-oxygen double bonds. Due to the higher heating rate and lack of a holding step during processing,the resulting thermoplastic fibers did not completely convert to thermoset materials, allowing partially melted, adjacent fibres to fuse. Fiber surfaces were smooth and homogeneous. Of the various methods evaluated herein, carbon fibers derived from pressure-treated EBO and PVC exhibited the highest tensile strength. This work shows that enhancing the naphthenic component of a pitch precursor through the co-carbonization of pre-treated EBO with PVC improves the oxidative properties of the resulting carbon fibers.

• Macromolecular Research
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• v.14 no.5
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• pp.524-529
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• 2006

New, thermally robust, arylenevinylene conjugated polymers, including poly(9,9-dioctylfluorenyl-2,7-vinylene) [poly(FV)] and poly[2-(3'-dimethyldodecylsilylphenyl)-1,4-phenylenevinylene] [poly(m-SiPhPV)], were synthesized and used for the fabrication of efficient photovoltaic cells. Bulk heterojunction photovoltaic cells fabricated by blending one of the polymers, [poly(FV)], [poly(m-SiPhPV)], and poly(FV-co-m-SiPhPV), with the fullerene derivative [6,6]-phenyl-$C_{61}$-butyric acid methyl ester (PCBM) were found to have a power conversion efficiency of up to 0.038%..

• Macromolecular Research
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• v.17 no.12
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• pp.963-968
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• 2009

Liquid crystal (LC; E7 and/or ML-0249)-embedded, poly(vinylidenefluoride-co-hexafluoropropylene) (PVdF-co-HFP)-based, polymer electrolytes were prepared for use in dye-sensitized solar cells (DSSCs). The electrolytes contained 1-methyl-3-propylimidazolium iodide (PMII), tetrabutylammonium iodide (TBAI), and iodine ($I_2$), which participate in the $I_3^-/I^-$ redox couple. The incorporation of photochemically stable PVdF-co-HFP in the DSSCs created a stable polymer electrolyte that resisted leakage and volatilization. DSSCs, with liquid crystal(LC)-embedded PVdF-co-HFP-based polymer electrolytes between the amphiphilic ruthenium dye N719 absorbed to the nanocrystalline $TiO_2$ photoanode and the Pt counter electrode, were fabricated. These DSSCs displayed enhanced redox couple reduction and reduced charge recombination in comparison to that fabricated from the conventional PVdF-co-HFP-based polymer electrolyte. The behavior of the polymer electrolyte was improved by the addition of optimized amounts of plasticizers, such as ethylene carbonate (EC) and propylene carbonate (PC). The significantly increased short-circuit current density ($J_{sc}$, $14.60\;mA/cm^2$) and open-circuit voltage ($V_{oc}$, 0.68 V) of these DSSCs led to a high power conversion efficiency (PCE) of 6.42% and a fill factor of 0.65 under a standard light intensity of $100\;mW/cm^2$ irradiation of AM 1.5 sunlight. A DSSC fabricated by using E7-embedded PVdF-co-HFP-based polymer electrolyte exhibited a maximum incident photon-to-current conversion efficiency (IPCE) of 50%.

• Proceedings of the Korean Geotechical Society Conference
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• 2005.03a
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• pp.71-80
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• 2005

More than 100 bridges have been annually collapsed or seriously damaged by scouring in Korea. It is extremely hard to understand the complicated scour mechanism and estimate the scour depth with accuracy in fields, however since scouring is a very complex manifestation of sediment transport unable to describe with a simple mathematical tool. In order to obtain the reasonable solution to bridge scouring, therefore, the interdisciplinary co-operation is strongly recommended. In this study the special task force team for the scour problems around Incheon 2nd bridge piers is made, in which all kinds of scour oriented researches such as oceangraphic survey, hydraulic model test, numerical simulation, scour rate test, real-time scour monitoring, etc will be carried out. This paper provides this interdisciplinary procedure in details.

• Journal of the Korean Society of Industry Convergence
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• v.26 no.6_3
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• pp.1183-1195
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• 2023

In this study, we collected and analyzed domestic and international studies related to watersheds in the forest sector. Keyword co-occurrence analysis was conducted using the VOSviewer program to identify the research areas of domestic and international studies and the network structure to compare research trends. As a result, the number of research articles in international watershed-related studies showed an overall increasing trend, and the research areas were diverse and located close to each other, indicating that many convergence studies were conducted. On the other hand, the number of papers in domestic watershed-related studies seems to have stagnated overall from the past to the present, and the research areas are mainly focused on forest disasters and hydrology, with limited interdisciplinary convergence studies. In addition, in both domestic and international studies, watersheds are currently mentioned as research sites rather than management or analysis units in the forest sector. It is important to actively promote interdisciplinary research in Korea to provide a scientific and balanced basis for watershed-level forest management planning.

• Food Science and Preservation
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• v.23 no.4
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• pp.576-584
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• 2016

In this study, antioxidant activities and physicochemical properties of chocolate fermented with Lactobacillus plantarum CK10 were investigated. The pH level decreased from $5.26{\pm}0.02$ to $3.98{\pm}0.06$ during fermentation while titratable acidity increased from $5.36{\pm}0.19$ to $13.31{\pm}0.34$. The total polyphenol and flavonoid contents slightly increased during fermentation, but it was numerically negligible. Slight increase and decrease in the radical scavenging activities of chocolate, against DPPH-, ABTS-, and alkyl-radical, were observed during 32 hr of fermentation, but the changes were not statistically relevant. Composition ratios (% area by GC analysis) of lactic acid, xanthosine, and theobromine increased with fermentation time while hydroxymethylfurfural (HMF) and caffeine decreased after 32 hr of fermentation, in the order of xanthine (22.7%), theobrome (20.0%), lactic acid (14.9%), HMF (9.1%) and caffeine (9.0%). However, there was no remarkable changes in theobromine and caffeine contents in chocolate during fermentation.

• Journal of Korean Medical classics
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• v.22 no.2
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• pp.1-22
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• 2009

The existing interpretations and translations do not give adequate explanations about hidden meanings of the oriental theory, making it not easy for other researchers not majoring in oriental medicine to understand oriental medical classics. For other researchers who are trying to understand oriental medical classics and perform interdisciplinary co-research, we suggest there should be more detailed explanations about the hidden meaning of oriental theory such as Eumyang(陰陽, Yinyang) theory, Five-phase[五行] theory, Un-gi(運氣) theory. This paper, interpreting and translating the east(東), the west(西), the south(南), the north(北) in "Hwangjenaegyeong Somun(黃帝內經 素問)" focusing on the meaning of each character, will be a good example of such detailed explanation.