• Journal of the Korean Applied Science and Technology
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• v.34 no.4
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• pp.986-994
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• 2017

In this paper, $CO_2$ absorption of scrubber was tested for removal of high concentration $CO_2$. Liquid to gas ratio($18L/m^3$) and Superficial velocity(0.14 m/s) was determined through Lab-scale test. As flow rates increase 1, 2, 3, 4 and $5m^3/min$, $CO_2$ removal efficiency decrease 98.47%, 96.46%, 92.95%, 89.71% and 85.49%. Also, the scrubber operation made energy improvement(5.4%), energy saving(11.5 TOE/year) and greenhouse gases reduction(6.5 TC/year).

• Journal of the Korea Society of Computer and Information
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• v.23 no.9
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• pp.87-96
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• 2018

The purpose of this study was to identify the preferred materials and design characteristics of nursing home clothes in order to collect the basic data necessary for the elderly nursing home clothes. It was to utilize the elderly nursing home clothes considering elderly body shape, hand function, illness. This study was conducted by questionnaire method and SPSS ver. 20.0 program was used. The preference for nursing home clothes material was high for cotton, and it was found that they prefer soft, stretch material, warm feeling material, and lightweight material. In the hygienic aspect, they favored sweat-absorbent materials, and preferred laundry- care-resistant materials with poor wrinkles and dirtiness. The nursing home clothes preferred a two piece form consisting of a round neckline, two pockets on both sides, a waistband of rubber band, long lengths, and a waistline pants. The most important function in the nursing home clothes was recognized as wearing comfort. Aesthetics, symbolism, color and print pattern were recognized as not important functions. Therefore, it is necessary to focus on the functional part such as wearing comfort in the design of the nursing home clothes. The material is also hygienic and comfortable to wear. In the case of the elderly, it is necessary to provide convenience for the wear of clothes through the development of stretchable material and detachment device since the movement range of muscles, arms, and legs is reduced. Based on this study, we will utilize it for the development of nursing home suit considering the characteristics of elderly person in the elderly society. It is to develop functional materials for the elderly in need of nursing home, to develop the pattern considering the elderly body shape, and to develop the desorption device considering the movement of the hand.

• Journal of Convergence for Information Technology
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• v.9 no.6
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• pp.233-241
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• 2019

This study was conducted on women in their 20s and 30s living in the Seoul metropolitan area by using questionnaires on the recognition and purchase behavior of mask packs. According to this study, although there is high interest in skin beauty, the recognition of characteristics and distinctions according to mask pack type was found to be insufficient. After using mask packs, 51.5% of those surveyed were satisfied with their efficacy and effectiveness. When using the mask pack, the Sheet type mask pack was discontented with usability, size, Close Adhesion and skin irritation, Hydrogel type is material, sleeping type is content and absorbent, cellulose type pack was found to have the same discomfort with the material as the hydro gel type. Through the results of this study, the possibility of utilization as basic data for mask pack market marketing was confirmed.

• Journal of the Institute of Convergence Signal Processing
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• v.21 no.4
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• pp.177-182
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• 2020

Interest in heat pumps is increasing as an eco-friendly and energy-saving heating method. In particular, in order to develop a heat pump capable of heating in a low-temperature area, research to prevent frost on the surface of the outdoor unit is increasing. In other words, when heating through a heat pump in a low-temperature area, a frost layer is formed on the surface of the outdoor unit, which lowers the heat transfer performance, thereby reducing the heating capacity. Therefore, in this study, an adsorption-type dehumidification system is attached to remove the moisture vapor of the air into the outdoor unit of the heat pump. It is believed that this study can suggest the most effective dehumidification method in low temperature regions. In addition, it is expected that a heat pump with high energy efficiency can be developed by attaching an adsorption dehumidifying system to the front of the outdoor unit of the heat pump.

• Journal of dental hygiene science
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• v.21 no.1
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• pp.45-51
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• 2021

Background: Periodontal disease, also known as gum disease, is a major dental inflammatory disease with a very high prevalence; it is the main cause of tooth loss. Therefore, diagnostic biomarkers that can monitor gum inflammation are important for oral healthcare. Since the gingival crevicular fluid (GCF) adequately reflects changes in the periodontal environment, they have become a target for the development of effective diagnostic biomarkers for periodontitis. In the present study, the level of the target molecules suggested as diagnostic biomarkers for periodontitis were analyzed in GCF samples collected from healthy individuals and periodontitis patients. In addition, useful targets for the diagnosis of periodontitis were evaluated. Methods: GCF samples were collected from healthy individuals and periodontitis patients using absorbent paper points. SDS-PAGE and Coomassie staining were performed for protein analysis. The protein concentrations of GCF specimens were determined using the Bradford method. The levels of the target molecules appropriate for diagnosing periodontal disease were measured by ELISA, according to the manufacturer's protocol. Results: The protein concentration of GCF collected from periodontitis patients was 3.72 fold higher than that in an equal volume of GCF collected from healthy individuals. ELISA analysis showed that the level of interukin-6 (IL-6), IL-8, metalloproteinases 2 (MMP-2), MMP-9, tumor necrosis factor-alpha (TNF-α), azurocidin, and odontogenic ameloblast-associated protein (ODAM) were higher in the GCF samples from the periodontitis patients than in those from the healthy individuals. However, the level of IL-6 and TNF-α were relatively low (> 5 pg/ml). The prostaglandin E2 (PGE2) levels were not significantly different between the two GCF samples. Conclusion: These results indicate that IL-8, MMP-2, MMP-9, azurocidin, and ODAM are potentially useful diagnostic biomarkers for periodontitis; combining multiple biomarkers will improve the diagnostic accuracy of periodontitis.

• 한국신재생에너지학회:학술대회논문집
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• 2010.06a
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• pp.134-134
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• 2010

Fuel cell is a device that directly converts chemical energy in the form of a fuel into electrical energy by way of an electrochemical reaction. In the anode for a high temperature fuel cell, nickel or nickel alloy has been used in consideration of the cost, oxidation catalystic ability of hydrogen which is used as fuel, electron conductivity, and high temperature stability in reducing atmosphere. Most MCFC stacks currently operate at an average temperature of $650^{\circ}C$. There is some gains with decreased temperature in MCFC to diminish the electrolyte loss from evaporation and the material corrosion, which could improve the MCFC life. However, operating temperature has a strong related on a number of electrode reaction rates and ohmic losses. Baker et al. reported the effect of temperature (575 to $650^{\circ}C$). The rates of cell voltage loss were 1.4mV/$^{\circ}C$ for a reduction in temperature from 650 to $600^{\circ}C$, and 2.16mV/$^{\circ}C$ for a decrease from 600 to $575^{\circ}C$. The two major contributors responsible for the change in cell voltage with reducing operation temperature are the ohmic polarization and electrode polarization. It appears that in the temperature range of 550 to $650^{\circ}C$, about 1/3 of the total change in cell voltage with decreasing temperature is due to an increase in ohmic polarization, and the electrode polarization at the anode and cathode. In addition, the oxidation reaction of hydrogen on an ordinary nickel alloy anode in MCFC is generally considered to take place in the three phase zone, but anyway the area contributing to this reaction is limited. Therefore, in order to maintain a high performance of the fuel cell, it is necessary to keep this reaction responsible area as wide as possible, that is, it is needed to keep the porosity and specific surface area of the anode at a high level. In this study effective anodes are prepared for low temperature MCFC capable of enhancing the cell performance by using zirconium hydride at least in part of anode material.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.13 no.3
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• pp.171-180
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• 2015

This study was performed on the removal of Cs, one of the main high- radioactive nuclides contained in the high-radioactive seawater waste (HSW), by adsorption with IE911 (crystalline silicotitanate type). For the effective removal of Cs and the minimization of secondary solid waste generation, adsorption of Cs by IE911 (hereafter denoted as IE911-Cs) was effective to carry out in the m/V (ratio of absorbent weight to solution volume) ratio of 2.5 g/L, and the adsorption time of 1 hour. In these conditions, Cs and Sr were adsorbed about 99% and less than 5%, respectively. IE911-Cs could be also expressed as a Langmuir isotherm and a pseudo-second order rate equation. The adsorption rate constants (k₂) were decreased with increasing initial Cs concentrations and particle sizes, and increased with increasing ratios of m/V, solution temperatures and agitation speeds. The activation energy of IE911-Cs was about 79.9 kJ/mol. It was suggested that IE911-Cs was dominated by a chemical adsorption having a strong bonding form. From the negative values of Gibbs free energy and enthalpy, it was indicated that the reaction of IE911-Cs was a forward, exothermic and relatively active at lower temperatures. Additionally, the negative entropy values were seen that the adsorbed Cs was evenly distributed on the IE911.

• Membrane Journal
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• v.30 no.4
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• pp.269-275
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• 2020

In this study, CO₂ separation experiment was performed on a CH₄/CO₂ mixed gas using a ceramic hollow fiber membrane contactor (HFMC). In order to fabricate high-performance HFMC, experiments were conducted to manufacture high-permeability hollow fiber membranes, and the prepared hollow fiber membranes were evaluated through N₂ gas permeation experiments. HFMC for CH₄/CO₂ mixed gas separation was manufactured using the manufactured high-permeability hollow fiber membrane. In the experiment, mixed gas of CH₄/CO₂ (34.5% CO₂, CH₄ balance) and monoetanolamine (MEA) was used, and the effect of CO₂ removal efficiency on the flow rate of the absorbent was evaluated. The CO₂ removal efficiency increased as the liquid flow rate increased, and the CO₂ absorption flux also increased with the liquid flow rate.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.4
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• pp.111-117
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• 2017

This study examined the material properties of Korean rice husk ash (RHA) according to the manufacturing process, and evaluated the feasibility of its use as a new admixture for high strength concrete. For this purpose, its particle size distribution, chemical composition, and microstructure were analyzed under various parameters, such as calcination temperature ($400^{\circ}C$, $650^{\circ}C$, and $900^{\circ}C$) and the inclusion of a milling process. X-ray fluorescence analysis confirmed that the silicon oxide ($SiO_2$) content of RHA was improved to more than 92% with a calcination process at $650^{\circ}C$ or higher. In addition, microstructural analysis showed that the RHA calcined at $650^{\circ}C$ has a porous structure. Because of this, the absorption capacity of the RHA was improved. On the other hand, when the milling process was applied, the porous structure was destroyed; thus, the absorption capacity tended to decrease further. Based on the analysis results, it was concluded that RHA calcined at $650^{\circ}C$ can be used as an admixture for high strength concrete, which possesses functions of both a shrinkage reducing agent and a pozzolanic activator.

• Journal of the Korea Organic Resources Recycling Association
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• v.8 no.3
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• pp.81-88
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• 2000

Composting of N-rich wastes such as food waste and wastewater sludges can be associated loss of with substantial gaseous N, which means loss of an essential plant nutrient but may also lead to environmental pollution. We investigated the behavior of nitrogenous materials during the first high-rate phase in composting of food waste. Air dried food waste was mixed with shredded waste paper or wood chip and reacted in a bench scale composting reactor. Samples were analyzed for pH, ammonia, oxidized nitrogen and organic nitrogen. The volatilized ammonia nitrogen was also analyzed using sulfuric acid as an absorbent solution. Initial progress of composting reaction greatly influenced the ammonification of organic nitrogen. A well-balanced composting reaction with an addition of active compost as an inoculum resulted in the promoted mineralization of organic nitrogen and volatilization of ammonia. The prolongation of initial low pH period delayed the production of ammonia. It was also found that nitrogen loss was highly dependent on the air flow supplied. With an increase in input air flow, the loss of nitrogen as an ammonia also increased, resulted in substantial reduction of ammonia content in compost. The conversion ratio of initial nitrogen into ammonia was in the range of 28 to 38% and about 77~94% of the ammonia produced was escaped as a gas. Material balance on the nitrogenous materials was demonstrated to provide an information of importance on the behavior of nitrogen in composting reaction.