• The Research Journal of the Costume Culture
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• v.11 no.6
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• pp.967-971
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• 2003

As the concerns over health increased in 1990's, research and development on the health material were also activated. The development of UV-cut textile became the hot issue, because the damage of W irradiation due to ozone depletion has become widely known. UV-cut effect is determined by the material, the color, the organization and the density of UV-cut fibers. UV-cut effect is very different according to the fibers. Polyester is known to have a better effect. Even in the same textile material, staple fiber has more effect than filament fiber. Different colors have different offsets. Although textiles have the same color, the effects can be different according to the depth of color. PET, PET/cotton blend, nylon and cotton fabrics were ultraviolet cutting finished with padding method using several absorbers. These UV-cut effect can be improved through the processing. Safety of UV-cut textile for the body must be considered future, Until now the figure of the UV-cut effects has been emphasized. There has been no experiment on the human body, although the textiles are directly on the human body. Futhermore there os no safety standard of UV-cut textiles. Therefore every effort will be made to set the standard UV-cut processing is established. The need of UV-cut products will be known to the consumers.

• Advances in nano research
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• v.12 no.6
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• pp.593-603
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• 2022

The critical buckling temperature rise of a newly proposed piezoelectrically active sandwich plate (ASP) has been investigated in this work. This structure includes a porous polymeric layer integrated between two piezoelectric nanocomposite layers. The piezoelectric material is made of a passive polymeric material that is activated by lead-free nanowires (NWs) of zinc oxide (ZnO) embedded inside the matrix. In both nanocomposite layers and porous core, functional graded (FG) patterns have been considered for the distributions of ZnO NWs and voids, respectively. By adopting a higher-order theory of plates, the governing equations of thermal buckling are obtained. This set of equations is then treated using an extended mesh-free solution. The effects of plate dimensions, porosity states, and the nanowire parameters have been investigated on the critical buckling temperature rises of the proposed lightweight ASPs with different boundary conditions. The results disclose that the use of porosities in the core and/or mixing ZnO NWs in the face sheets substantially arise the critical buckling temperatures of the newly proposed active sandwich plates.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2022.11a
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• pp.169-170
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• 2022

Due to the higher use of nonrenewable fossil fuel energy, environment friendly sustainable energy from waste materials is attracting attention of the researchers. Considering that, jute stick (JS) biochar has been considered for this study for ecofriendly and sustainable thermal energy storage application. Waste jute sticks (JS), which are being mainly used as a fuel for cooking purpose, have been pyrolyzed to produce porous biochar and have been used for shape stabilization of stearic acid (SA) as phase change material (PCM). SA at 1:1 ratio has been incorporated into the activated JS biochar to concoct shape-stabilized phase change composite (SAJS). The SAJS has been evaluated by different techniques such as Fourier transform-infrared spectroscope (FT-IR), scanning electron microscopy (SEM), differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA). The obtained composite PCM has shown excellent shape stability with a high latent heat storage, suggesting its suitability for thermal energy storage applications.

• Journal of the Korean Wood Science and Technology
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• v.43 no.1
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• pp.135-143
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• 2015

This study evaluated fuel properties of composite materials which were prepared by mixing a waste activated carbon from the used purifier filter with torrefied wood powder. Wood species of the raw material of torrefied wood powder are oak wood (Quercus serrata Thunb. ex Murray) and pine wood (Pinus densiflora Siebold & Zucc). And the treatment conditions used for this study were 300 s, 450 s, and 600 s at $200^{\circ}C$ for the wood roaster. Also, the mixing ratios are 5 : 95, 10 : 90, 15 : 85, 20 : 80, 40 : 60, 60 : 40 and 80 : 20 (waste activated carbon : torrefied wood powder). The fuel properties such as highly heating value (HHV), elementary analysis and ash content were evaluated. The results obtained are followings; 1. Despite the same treatment condition of wood roasting, pine wood has higher carbon contents than oak wood. Therefore, pine wood indicated the optimum carbonization at low temperature and short treatment times. 2. The gross calorific value and ash content increased as the mixing ratio of waste activated carbon increased. 3. Mixtures of the waste activated carbon and torrefied wood powder showed greater gross calorific value than those of the mixtures of waste activated carbon and the untreated wood powder. Also, the pine wood resulted in higher heating value that thaose of the oak wood. 4. When composite fuels that were composed waste activate carbon and wood powder are used, higher temperature conditions are required because the combustion is incomplete at $800^{\circ}C$ and 4 hours. 5. The increasing rate of the gross calorific value of mixtures of waste activated carbon and untreated wood powder is higher than does the mixtures of waste activated carbon and torrefied wood powder. Also, this phenomenon is more obvious for pine woods. Therefore, an optimal mixing ratio of waste activated carbon was determined to be between 5% and 10% (wt%). Also, this condition satisfied the requirement of the No.1 grade of wood pellet.

• Journal of the Korean Ceramic Society
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• v.49 no.5
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• pp.475-483
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• 2012

High capacitance X5R MLCCs based on $BaTiO_3$ ceramic dielectric layers exhibit a single broad, asymmetric arc shape impedance and modulus response over the wide frequency range between 1 MHz to 0.01 Hz. Analysis according to the conventional brick-layer model for polycrystalline conductors employing a series connection of multiple RC parallel circuits leads to parameters associated with large errors and of little physical significance. A new parametric impedance model is shown to satisfactorily describe the experimental spectra, which is a parallel network of one resistor R representing the DC conductivity thermally activated by 1.32 eV, one ideal capacitor C exactly representing bulk capacitance, and a constant phase element (CPE) Q with complex capacitance $A(i{\omega})^{{\alpha}-1}$ with ${\alpha}$ close to 2/3 and A thermally activated by 0.45 eV or ca. 1/3 of activation energy of DC conductivity. The feature strongly indicate the CK1 model by J. R. Macdonald, where the CPE with 2/3 power-law exponent represents the polarization effects originating from mobile charge carriers. The CPE term is suggested to be directly related to the trapping of the electronic charge carriers and indirectly related to the ionic defects responsible for the insulation resistance degradation.

• Journal of The Korean Society of Agricultural Engineers
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• v.58 no.2
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• pp.1-9
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• 2016

This study aims to assess the effectiveness of activated carbon (AC) and crushed concrete (CC) as capping material to block the release of nitrogen, phosphorus, and organic substance from reservoir sediments. The efficiency of AC and CC as capping material was evaluated in a reactor in which a 1 or 3 cm thick layer of capping materials was placed on the sediments collected from Mansu reservoir in Anseong-city. Dissolved oxygen (DO) concentration, total nitrogen (T-N), total phosphorus (T-P), and chemical oxygen demand (COD) concentration in reservoir water above the uncapped sediments and capping material were monitored for 45 days. The release rate of T-N was in the following increasing order: AC 3 cm ($1.18mg/m^2{\cdot}d$) < CC 1 cm ($2.66mg/m^2{\cdot}d$) < AC 1 cm ($2.94mg/m^2{\cdot}d$) < CC 3 cm ($3.42mg/m^2{\cdot}d$) < uncapped ($4.59mg/m^2{\cdot}d$). The release rate of T-P was in the following increasing order: AC 3 cm ($0mg/m^2{\cdot}d$) $${\approx_-}$$ CC 3 cm ($0mg/m^2{\cdot}d$) < CC 1 cm ($0.03mg/m^2{\cdot}d$) < AC 1 cm capped ($0.07mg/m^2{\cdot}d$) < uncapped ($0.24mg/m^2{\cdot}d$). The release of nitrogen and phosphorus were effectively blocked by AC capping of 3 cm thickness, and CC capping of 3 cm thickness effectively controlled the release of phosphorus. The order of increasing COD release rate was as follows: AC 3 cm ($0mg/m^2{\cdot}d$) $${\approx_-}$$ CC 3 cm ($0mg/m^2{\cdot}d$) < CC 1 cm ($5.03mg/m^2{\cdot}d$) < AC 1 cm ($7.28mg/m^2{\cdot}d$) < uncapped ($10.05mg/m^2{\cdot}d$), indicating that AC and CC capping effectively interrupted the release of organic contaminants from the sediments. It was concluded that AC and CC could effectively block the release of T-N, T-P and COD release from contaminated reservoir sediments.

• Applied Chemistry for Engineering
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• v.22 no.5
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• pp.501-507
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• 2011

To develop environmental-friendly insulating composite materials, natural cellulose and porous ceramic balls were used as core materials and activated Hwangtoh was used as a binder. Various specimens were prepared with different water/binder ratios and core material/binder ratios. The physical properties of these specimens were then investigated through compressive strengths, flexural strengths, absorption test, hot water resistance test, pore analysis, thermal conductivity, and observation of micro-structures using scanning electron microscope. Results showed that the maximum compressive strength varied appreciably with the water/binder ratios and core material/binder ratios, but the flexural strength increased with the core material/binder ratios regardless of water/binder ratios. The compressive strength and the flexural strength measured after the hot water resistance test decreased remarkably compared to those measured before test. The pore analysis measured after the hot water resistance test showed that total pore volume, porosity and average pore diameter decreased, while bulk density increased by the acceleration of hydration reaction of binder in the hot water. The thermal conductivity decreased gradually with an increase of core material/binder ratios. It can be evaluated that the composite insulation materials having good insulating properties and mechanical strengths can be used in the field.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.43 no.5
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• pp.555-566
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• 2023

In this study, a composite phase change material (CPCM) produced using the SOL-GEL technique was developed as a thermal energy storage medium for low-temperature applications. Tetradecane and activated carbon (AC) were used as the core and supporting materials, respectively. The tetradecane phase change material (PCM) was impregnated into the porous structure of AC using the vacuum impregnation method, and a thin layer of silica gel was coated on the prepared composite using the SOL-GEL process, where tetraethyl orthosilicate (TEOS) was used as the silica source. The thermal performance of the CPCM was analysed using differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). DSC results showed that the pure tetradecane PCM had melting and freezing temperatures of 6.4℃ and 1.3℃ and corresponding enthalpies 226 J/g and 223.8 J/g, respectively. The CPCM exhibited enthalpy of 32.98 J/g and 27.7 J/g during the melting and freezing processes at 7.1℃ and 2.4℃, respectively. TGA test results revealed that the AC is thermally stable up to 500℃, which is much higher than the decomposition temperature of the pure tetradecane, which is around 120℃. Moreover, in the case of AC-PCM and CPCM thermal degradation started at 80℃ and 100℃, respectively. The chemical stability of the CPCM was studied using Fourier-transform infrared (FT-IR) spectroscopy, and the results confirmed that the developed composite is chemically stable. Finally, the surface morphology of the AC and CPCM was analysed using scanning electron microscopy (SEM), which confirmed the presence of a thin layer of silica gel on the AC surface after the SOL-GEL process.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.5
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• pp.1-6
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• 2021

Mercury, once released, is not destroyed but accumulates and circulates in the natural environment, causing serious harm to ecosystems and human health. In the United States, sulfur-impregnated activated carbon is being considered for the removal of vapor mercury from the flue gas of coal-fired power plants, which accounts for about 32 % of the anthropogenic emissions of mercury. In this study, a high-efficiency porous mercury adsorption material was developed to reduce the mercury vapor in the exhaust gas of coal combustion facilities, and the mercury adsorption characteristics of the material were investigated. As a result of the investigation of the vapor mercury adsorption capacity at 30℃, the silica nanotube MCM-41 was only about 35 % compared to the activated carbon Darco FGD commercially used for mercury adsorption, but it increased to 133 % when impregnated with 1.5 % sulfur. In addition, the furnace fly ash recovered from the waste copper regeneration process showed an efficiency of 523 %. Furthermore, the adsorption capacity was investigated at temperatures of 30 ℃, 80 ℃, and 120 ℃, and the best adsorption performance was found to be 80 ℃. MCM-41 is a silica nanotube that can be reused many times due to its rigid structure and has additional advantages, including no possibility of fire due to the formation of hot spots, which is a concern when using activated carbon.

• Journal of Applied Biological Chemistry
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• v.53 no.3
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• pp.132-138
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• 2010

A gene encoding a putative alanine racemase in B. pseudomycoides was cloned and expressed in Escherichia coli BL21(DE3) using a pET-21 vector harbouring 6xHistidine tag. Affinity purification of the recombinant alanine racemase with a nickel resin resulted in one band by SDS-PAGE analysis. The purified enzyme showed a molecular weight of 46 kDa. The enzyme was the most active toward L-alanine and secondly D-alanine, implying that the enzyme is an alanine racemase. D-cysteine significantly inhibited the enzyme activity and also L-cysteine to a lesser extent. The enzyme was considerably activated by addition of pyridoxal-5'-phosphate (PLP), showing that 73% increase in activity was observed at 0.3 mM, compared to control. The enzyme was the most active at pH 9.0 and more stable at alkaline pHs than acidic pHs.