• Applied Chemistry for Engineering
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• v.25 no.3
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• pp.292-299
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• 2014

In this study, nitrogen doped carbon felt (CFt) is prepared using thermal oxidation and liquid phase ammonia treatment to improve the efficiency for vanadium redox flow batteries (VRFB). The electrochemical properties of prepared CFt electrodes are investigated using cyclic voltammetry (CV) and charge/discharge test. The XPS result shows that the increase of liquid phase ammonia treatment temperature leads to the increased nitrogen functional group on the CFt surface. Redox reaction characteristics using CV reveal that the liquid phase ammonia treated CFt electrodes are more reversible than the thermally oxidized CFt. When CFt is treated by the liquid phase ammonia at $300^{\circ}C$, VRFB cell energy efficiency, voltage efficiency, and current efficiency are increased about 6.93%, 1.0%, and 4.5%, respectively, compared to those of the thermally oxidized CFt. These results are because nitrogen functional groups on CFt help to improve the electrochemical properties of redox reaction between electrode and electrolyte interface.

• Korean Chemical Engineering Research
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• v.57 no.3
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• pp.408-412
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• 2019

In this study, nitrogen doped carbon felt was prepared by pyrolysis of urea at high temperature and applied as an electrode for vanadium redox flow cell. Urea is easier to handle than ammonia and forms $NH_2$ radicals at higher temperatures, creating a nitrogen functional group on the carbon surface and acting as an active site in the vanadium redox reaction. Therefore, the discharge capacity of activated carbon felt electrodes using urea was 14.9 Ah/L at a current density of $150mA/cm^2$, which is 23% and 187% higher than OGF and GF, respectively. These results show the possibility that activated carbon felt electrode using urea can be used as electrode material for redox flow battery.

• Journal of Energy Engineering
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• v.24 no.3
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• pp.89-95
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• 2015

Carbon felts manufactured by (Co)CNF were subjected to heat treatment under different temperatures to use for the electrode of a redox-flow battery. BET and weight loss were tested to investigate the physical properties of the carbon felt according to the heat treatment conditions. SEM and XPS were also analyzed to characterize their surface area. In addition, electrical resistance, CV (cyclic voltammetry) and RFB charge on the electrode properties were examined in accordance with the heat treatment conditions with the discharge performance. The changes of physical properties on the carbon felt surface was confirmed via SEM and BET analysis, The most addition of oxygen functional groups on the carbon felt surface was obtained when one hour heat treatment at $550^{\circ}C$ and it was confirmed by XPS analysis. After resulting the CV tests, the active area of the electrode was the largest at $550^{\circ}C$ heat treatment. The heat treatment experiment of vanadium redox flow battery using the carbon felts were tested at $400^{\circ}C$, $500^{\circ}C$ and $550^{\circ}C$. As a result, the charge-discharge energy efficiency of the heat treatment electrode was 72.9% and 79.8%, at $400^{\circ}C$ and $500^{\circ}C$, respectively. The efficiency of the heat treatment electrode at $550^{\circ}C$ was the best as 79.8% at $550^{\circ}C$.

• Applied Chemistry for Engineering
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• v.33 no.5
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• pp.471-476
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• 2022

PP/KF felt was used to load a high content of kenaf fiber (KF) into polypropylene (PP), and polyurethane (PU) was used as a binder. In order to find an optimum composition ratio of the PU binder, the flexural strength of the PP/KF/PU felt composite according to the isocyanate and polyol ratio was evaluated. PP-g-MAH grafted with maleic anhydride (MAH) was applied as a compatibilizer. Tensile, flexural, and impact properties were evaluated to consider changes in mechanical properties of the PP/KF/PU felt composite, and the properties were improved.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.32 no.3
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• pp.58-68
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• 2014

Christian Cay Lorenz Hirschfeld is often regarded as 'a father of landscape garden art.' He was an aesthetics professor and garden theoretician in the $18^{th}$ century. He put forth the most comprehensive garden theory book in five volumes between 1779 and 1785. His book, Theorie der Gartenkunst, was translated and widely circulated in his contemporary. The book, which dealt with diverse aspects of garden art such as history, design, material, and type, urged to promote the prevalence of landscape garden in European continents as well as in Germany. However, there have scarcely been discourses in the Hirschfeld's garden theory. This essay aims to review Hirschfeld's garden thoughts in his book critically and to reinterpret some issues in the contemporary landscape theory and practice. Hirschfeldian theory was the product of $18^{th}$ century German Enlightenment and romanticism. At that time, Nature was regarded as divine realm. There was a German affinity with natural world. The spread of reading culture and the fashion of travel literature were another background of the success of his garden literature. Several issues in Hirschfeld garden theory will discussed here. First, privileging garden art was the most significant contribution in his theory. He emphasized that garden art was the most advanced art form among all art genres. Second, garden art was grounded on the mimesis of nature. The ambiguous relationship between nature and art still existed in garden making. However, garden art can be flourished when utilizing the potency of nature in itself. Third, there was the association between the image and the idea in experiencing the garden. Some garden scenes stimulated the related emotional responses such as cheerful and merry, softly melancholic, romantic, solemn etc. Fourth, the movement was the essential aspect of garden art. Motion and emotion are come together in garden experience. To represent the landscape garden style in suitable way, the sketch or image seems to be preferable than the plans and views. Finally, garden art was composing of not only the physical space but also the spirit of place. He maintained the garden art as hortus moralis should be a social metaphor. Hirschfeldian garden theory has often been criticized as the lack of practical power and the old fashioned idea. However, his theory influenced on formulating the idea of public park in $19^{th}$ century. Moreover, there are still some visionary aspects of his theory such as the reevaluation of garden art, the emphasis of locality and the introduction of Mittelweg idea. Recently, gardening culture are prevalent in various realms of art and life. Hirschfeld's garden theory as humanistic landscape theory can provide us some insights in the contemporary practices.

• Journal of the Korean Electrochemical Society
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• v.12 no.3
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• pp.263-270
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• 2009

Carbon felt surface was modified by heat or acid treatment in order to use for the electrode of a redox-flow battery. Polymers on the surface of carbon felt was removed and oxygen-containing functional group was attached after the thermal treatment of carbon felt. Thermal treatment was better for the stability of the carbon structure than the acid treatment. Oxygen-containing functional group on the thermally treated carbon felt at 500$^{\circ}C$ was confirmed by XPS and elementary analysis. BET surface area was increased from nearly zero to 96 $m^2/g$. Thermally treated carbon felt at 500$^{\circ}C$ showed lower activation polarization than the thermally treated carbon felt at 400$^{\circ}C$ and the acid-treated carbon felt in the cyclicvoltammetry and polarization experiments. The thermally treated carbon felts at 400$^{\circ}C$ and 500$^{\circ}C$ and the acid-treated carbon felt was applied for the electrode to prepare vanadium redox flow battery. Voltage efficiencies of charge/discharge were 86.6%, 89.6%, and 96.9% for the thermally treated carbon felts at 400$^{\circ}C$ and 500$^{\circ}C$ and the acid-treated carbon felt, respectively.

• Cement Symposium
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• no.30
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• pp.194-198
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• 2003

• Culinary science and hospitality research
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• v.23 no.2
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• pp.181-188
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• 2017

Aronia is a superberry that contains antioxidants. Due to its nutritional value, it has received much attention and has been widely researched. In this study, the proportion of aronia powder applied to spelt wheat flour was measured with the pH ratio of the additive and respondents' preference was examined for the preferred addition to the additive population. As a result of the acidity measurement, the pH value tended to decrease as the amount of aronia powder was increased. As for the fermentation expansion rate, the volume of the dough added with aronia powder was measured to be slightly smaller than that without addition of aronia powder. Preference of breads with aronia powder added showed higher preference when 6% was added compared to when 3% of aronia powder was added. As a result of preference survey of breads containing aronia powder, the most preference was given to taste when 3% of aronia powder was added. Color, fragrance, and overall acceptance were the most preferred when 6% of aronia powder was added. Based on these results, the optimal mixing ratio of aronia powder to spelt flour bread was selected to be 6% of aronia powder.

• Journal of the Korea Fashion and Costume Design Association
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• v.8 no.1
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• pp.59-67
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• 2006

In textile industry of $21^{st}$ century, to develop materials and designs in fashion industry is being recognized widely as an urgent problem. In other words, the reality is that we must offer scarcity value and unique materials, and make a positive effort in a time when consumers' individuality appeals and an interest in fashion becomes higher. Felt is not only the oldest material in human history, but also a technique, and its applications are being handed down broadly. I have made various materials based mainly on a traditional felt technique using merino wool and nuno felt technique felting merino wool to cotton gauze. In nuno felt thing, I could observe that as wool and cotton was created as a single composite material, each material's aesthetic, sensuous, functional and emotional description became much more diversified. The purpose of this study is to produce fashion materials using materials with rich texture to meet the consumers' preference and diversity which are increasingly individualized, to design them and to seek possibility of developing differentiated wool materials which can satisfy the consumers' individuality demand and preference.

• Transactions of the Korean hydrogen and new energy society
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• v.28 no.2
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• pp.206-211
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• 2017

Carbon felt electrode for the vanadium redox-flow battery (VRFB) has been studied to see the effect of grephene oxide (GO) treatment on the surface of the carbon felt electrode. In this paper, surface of carbon felt electrodes were treated with various concentrations of grephene oxide. Electrochemical analysis, cyclic voltammetry (CV), was performed to investigate redox characteristics as electrode for VRFB. Also the effect of GO on the introduction of functional group on the surface of carbon felt electrodes were investigated using X-ray photoelectron spectroscopy (XPS), which discovered increase in the overall functional group content on the surface of carbon felts.