• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.4
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• pp.596-601
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• 2020

Silicon carbide is considered a potentially useful material for high-temperature electronic devices because of its large band gap energy and p-type or n-type conduction that can be controlled by impurity doping. Accordingly, the thermoelectric properties of -SiC powder prepared by refined diatomite were investigated for high value-added applications of natural diatomite. -SiC powder was synthesized by a carbothermal reduction of the SiO₂ in refined diatomite using carbon black. An acid-treatment process was then performed to eliminate the remaining impurities (Fe, Ca, etc.). n-Type semiconductors were fabricated by sintering the pressed powder at 2000℃ for 1~5h in an N2 atmosphere. The electrical conductivity increased with increasing sintering time, which might be due to an increase in carrier concentration and improvement in grain-to-grain connectivity. The carrier compensation effect caused by the remaining acceptor impurities (Al, etc.) in the obtained -SiC had a deleterious influence on the electrical conductivity. The absolute value of the Seebeck coefficient increased with increasing sintering time, which might be due to a decrease in the stacking fault density accompanied by grain or crystallite growth. On the other hand, the power factor, which reflects the thermoelectric conversion efficiency of the present work, was slightly lower than that of the porous SiC semiconductors fabricated by conventional high-purity -SiC powder, it can be stated that the thermoelectric properties could be improved further by precise control of an acid-treatment process.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2004.04a
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• pp.277-284
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• 2004

Batch experiments were conducted to investigate the sorption and desorption behaviors of PAHs (naphthalene, phenanthrene and pyrene) in soils. Three different soils montmorillonite KSF (foc =0.14%), masato (foc =0.08%), and diatomite (foc =0.007%) were investigated. The results of sorption-desorption experiment indicate that the sorption affinity of PAHs was in the order of montmorillonite > masato > diatomite. The Freundlich model was well fitted to the sorption and desorption data. Sorption affinity increased as loc increased. Desorption of PAHs from soils was biphasic composed of reversible and irreversible compartments. Desorption-resistance of phenanthrene in soils was also determined. The biphasic desorption model was used to explain desorption-resistance of phenanthrene in soils. The linear term represents reversible sorption fraction and Langmuinian-type term represents desorption-resistant fraction.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 1990.11a
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• pp.58-62
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• 1990

The size and concentration of wear debris in lubricating oil often reveal the operating condition of the rotating machinery. To evaluate the possible application of light attenuation measurement for the estimation of wear debris concentration in the lubricating oil, the light transmittance through the lubricating oil cell contaminated with various concentrations of diatomite particles was measured, the attenuation coefficient was estimated from the transmittance measurement and the coefficients were compared with those obtained from the scattering theory. The comparision showed good agreements between them. It is also noted that the experimentally determined attenuation coefficient showed almost linear relation with particle weight concentrations for the concentrations within the range of 2000 ppm. For the case of 0 ppm weight concentration of diatomite particles in the lubricating oil cell, the thickness of the cell required to give $100 \mu W$ light attenuation is 7.75 mm. This result indicates that the light attenuation method will be one of the possible candidates of machine failure diagnostic sensors for the estimation of wear debris concentration in the lubricating oil.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2017.05a
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• pp.182-183
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• 2017

This research identifies radon gas absorption mechanism by adsorption materials, replacing gypsum board with radon emissions, the density and absorption rates of magnesium were carried out using vermiculite, anthracite, powdered active carbon, bentonite, illite, diatomite as a basic study on the fire resistance type of radon Gas reduction type with absorption and decomposition. As a result of the experiment, diatomite showed the lowest density, and the highestt value was the highest. For the absorption rate, bentonite showed the highest absorption rate, and the anthracite showed the lowest absorption rate.

• Textile Coloration and Finishing
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• v.27 no.3
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• pp.210-218
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• 2015

In this study, natural substance and mineral materials was used for architectural interior wallpaper. Because natural substance and minerals are environment-friendly material with moisture adsorption and desorption properties. Natural substance and mineral materials was evaluated in moisture adsorption and desorption properties. Also, in the diatomite, the pores were observed on SEM photographs. Thus, it is supposed that moisture adsorption and desorption properties were influenced by the microstructure of the pore. The wallpaper according to the ratio of the mixture was analyzed for physical properties and moisture adsorption & desorption properties. As a result, we developed a wallpaper having excellent hygrothermal performance.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2018.05a
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• pp.230-231
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• 2018

Recently, the danger for radioactive materials has become a hot topic. Beginning with the Chernobyl nuclear accident in 1996, in 2011, the Fukushima nuclear power plant in Japan suffered major damage such as large-scale casualties and radioactive dangerous area selection. Concerns about leakage of radioactive materials due to recent earthquakes have been deepening in Korea, such as Wolsong Nuclear Power Plant in Gyeongju, and there is a growing interest in the safety of radioactive materials through the media and the media. However, the route to exposure to radioactive materials is not limited to these large-scale nuclear accidents. Typical examples of this are radioactive substances exposed in daily life. In the case of radon gas, the danger is being revealed through current events programs and news, and natural radiation exposure is attracting attention.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2019.05a
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• pp.184-185
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• 2019

Korea has defined fine dust as a social disaster as the problem of fine dust and air pollution becomes serious. Fine dust is classified as class one carcinogens because it is harmful to human body. When fine dusts enter the human body, they cause bronchial and skin diseases such as respiratory allergies, irritable pneumonia, asthma and atopy. As the air pollution becomes serious, the government is demanding measures to reduce fine dust. The polluted air in the outdoor is introduced into the room, thereby increasing the pollution degree of the indoor air quality. In this study, an adsorption type matrix for the improvement of indoor air quality was produced. Magnesium oxide and magnesium chloride were used as binders and diatomaceous earth was used as a adsorption material.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2014.05a
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• pp.280-281
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• 2014

Recently, it is certain that the increase of heating and cooling energy consumption by radical change in climate condition has caused serious problems related to environmental and energy concerns associated with increase of fossil fuel usage and carbon dioxide production as well as global warming. Therefore, various actions to reduce greenhouse gas and energy consumption have been prepared by world developed countries. The energy consumption by buildings approximately reaches 25% of total korea energy consumption. The greatest part in the buildings of the energy consumption is building facade. But a few research projects on concrete comprising more than 70% of outsider of buildings has been tried. This research is structural insulation concrete what improved insulation performance using micro form admixture and calcined diatomite powder and lightweight aggregate.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2013.11a
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• pp.40-41
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• 2013

The energy consumption by buildings approximately reaches 25% of total korea energy consumption. The greatest part in the buildings of the energy consumption is building facade. but a few research projects on concrete compising more than 70% of outsider of buildings has been tried. This research is structural insulation concrete what improved insulation performance using micro form admixture and calcined diatomite powedr and lightweight aggregate.

• Proceedings of the Korean Ceranic Society Conference
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• 2004.10a
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• pp.97.3-97.3
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• 2004