• Journal of the Korean earth science society
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• v.43 no.5
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• pp.639-646
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• 2022

Occurrence of black opaque hydrocarbon (pyrobitumen) in some Cretaceous Jinju sandstones of the Sindong Group, Gyeongsang Basin in Korea is first reported in this study. The pyrobitumen is developed on chlorite pore-lining cement, or impregnated into the outer zone of chlorite cement. Therefore, it seems to have been formed after the precipitation of chlorite cement, indicating the former presence of crude oil. The liquid hydrocarbons migrated into sandstones during moderate burial and these sandstones seem to have acted as a liquid hydrocarbon reservoir. The presence of pyrobitumen in the Jinju Formation indicates that this formation underwent deep burial after liquid hydrocarbon migration. As reservoir temperatures increased further, hydrocarbons were cracked and a solid pyrobitumen residue remained in the reservoir.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.35 no.1
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• pp.18-24
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• 2013

Purpose: This study is performed to determine the effects of titanium cap with various sizes of pores on bone formation during guided bone regeneration (GBR). Methods: Calvaria from 10 adult male rabbits were chosen as the recipient sites. A trephine bur with a diameter of 10 mm was used to form one round groove on each side of sagittal suture of the cranium, and a round bur with a diameter of 1.5 mm was used to form 6 small holes on the inner circles of round grooves to induce bleeding. In the control group, bone graft was not conducted, and closed titanium cap was fixed in the round groove. Bone graft was not performed in groups 1 and 2, but fixed on titanium caps with 0.2 mm, and 0.5 mm sized pores, respectively. For groups 3, 4, and 5, a synthetic bone graft material (${\beta}$-tricalcium phosphate, Cerasorb$^{(R)}$, Germany) was transplanted, and titanium caps without pore, with 0.2 mm and 0.5 mm sized pore were fixed, respectively. The animals were sacrificed 4 weeks after, and clinical, radiographical, and histomorphometrical evaluation of bone regeneration was performed. Results: In all groups, there were no clinical signs of infection, inflammation or wound dehiscence. Radiographic evaluation revealed well-defined semi-circular radiopacity inside the titanium cap of groups 3, 4, and 5. Histologically, the inner surface of the hemisphere was evenly lined with newly formed bone tissue, as well as grafted bone material in the group 3. In groups 4 and 5, the insertion of connective tissue was observed along the inner surface. However, the overall surface area between the grafts with different holes yielded no statistical significance in the histomorphometrical evaluation. Conclusion: Although the total area of newly formed bone showed no significant difference, excellent bone formation tendency was observed histologically when closed caps were used with bone graft was accompanied.

• Journal of Applied Biological Chemistry
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• v.60 no.4
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• pp.351-355
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• 2017

Tolaasin, peptide toxin produced by Pseudomonas tolaasii, causes a brown blotch disease on the cultivated mushrooms. Tolaasin peptides form membrane pores and disrupt cellular membrane structure. Molecular actions of tolaasin consist of the aggregation of peptide molecules, binding to the cell membrane, and formation of membrane pores. Therefore, the inhibitions of any of these actions are able to suppress the blotch disease. We have isolated and identified several tolaasin inhibitors (named tolaasin inhibitory factors, TIF) from food additives. TIFs were able to suppress the blotch-formation by the pathogen inoculated to the mushrooms. In this study, TIFs were incubated under various conditions and their activities for the inhibition of tolaasin-induced hemolytic activity were investigated. Since TIFs are unsaturated carbon compounds, they were sensitive to the air exposure and light irradiation. In the anaerobic conditions, TIFs were stable and their activities were decreased by 10% for three months. However, near 90% of TIF activity was suppressed by two weeks in the presence of air and sun light. Temperature did not show any significant effects on the activity of TIF, since storages at 5, 25, $45^{\circ}C$ did not show any difference. Therefore, for the stable storage of TIF compounds, container should be designed to be dark and air-tight.

• Korean Journal of Soil Science and Fertilizer
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• v.48 no.5
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• pp.351-360
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• 2015

Human influence on soil formation has dramatically increased with human civilization and industry development. Increase of anthropogenic soils induced researches on the anthropogenic soils; classification, chemical and physical characteristics of anthropogenic soils and plant growth from anthropogenic soils. However there have been no comprehensive analyses on soil pore or physical properties of anthropogenic soils from 3 dimensional images in Korea. The objectives of this study were to characterize physical properties of anthropogenic paddy field soils by depth and to find differences between natural and anthropogenic paddy field soils. Soil samples were taken from two anthropogenic and natural paddy field soils; anthropogenic (A_c) and natural (N_c) paddy soils with topsoil of coarse texture and anthropogenic (A_f) and natural (N_f) paddy soils with topsoil of fine texture. The anthropogenic paddy fields were reestablished during the Arable Land Remodeling Project from 2011 to 2012 and continued rice farming after the project. Natural paddy fields had no artificial changes or disturbance in soil layers up to 1m depth. Samples were taken at three different depths and analyzed for routine physical properties (texture, bulk density, etc.) and pore properties with computer tomography (CT) scans. The CT scan provided 3 dimensional images at resolution of 0.01 mm to calculate pore radius size, length, and tortuosity of soil pores. Fractal and configuration entropy analyses were applied to quantify pore structure and analyze spatial distribution of pores within soil images. The results of measured physical properties showed no clear trend or significant differences across depths or sites from all samples, except the properties from topsoils. The results of pore morphology and spatial distribution analyses provided detailed information of pores affected by human influences. Pore length and size showed significant decrease in anthropogenic soils. Especially, pores of A_c had great decrease in length compared to N_c. Fractal and entropy analyses showed clear changes of pore distributions across sites. The topsoil layer of A_c showed more degradation of pore structure than that of N_c, while pores of A_f topsoil did not show significant degradation compared with those of N_f. These results concluded that anthropogenic soils with coarse texture may have more effects on pore properties than ones with fine texture. The reestablished paddy fields may need more fundamental remediation to improve physical conditions.

• Journal of the Korean Ceramic Society
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• v.53 no.1
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• pp.34-42
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• 2016

Characteristics of wet flue gas desulfurization and in-furnace desulfurization of domestic and overseas limestone with different crystallinity and crystalline size are studied in this article. Properties of desulfurization were evaluated in relation to physicochemical/ mineralogical characteristics, degree of pore formation for different calcination temperatures and TNC(total neutralizing capability). TNC of domestic high crystalline limestone was lower than that of overseas one. On the other hand, the porosity after calcination was shown to be relatively high for domestic limestone, which had high initial rates of desulfurization reactions in-furnace. Based on low pore formation and porosity with high TNC of crystalline high-Ca limestones compared to macrocrystalline ones, the former are preferred for wet desulfurization processes.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.5
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• pp.927-938
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• 2000

When microorganism is injected into porous medium such as soils along with appropriate substrate and nutrients, biomass retained in the soil pore. Soil pore size and shape are varied from the initial condition as a result of biofilm formation, which make hydraulic conductivity reduced. In this research, hydraulic conductivity reduction was measured after microorganism are inoculated and cultured with synthetic substrates and nutrients. Biomass-soil mixture was evaluated its applicability to the field condition as an alternative liner material in landfill by measuring hydraulic conductivity change after repetitive freeze-thaw cycles. Resistance of biofilm to chemical solution and degree of biodegradation were measured through column test.

• Journal of Sensor Science and Technology
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• v.18 no.4
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• pp.307-310
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• 2009

This paper describes the formation of porous 3C-SiC by anodization. 3C-SiC thin films were deposited on p-type Si(100) substrates by APCVD using HMDS(Hexamethyildisilane: $Si_2(CH_3)_6$). UV-LED(380 nm) was used as a light source. The surface morphology was observed by SEM and the pore size was increased with increase of current density. Pore diameter of 70 $\sim$ 90 nm was achieved at 7.1 mA/cm$^2$ current density and 90 sec anodization time. FT-IR was conducted for chemical bonding of thin film and porous 3C-SiC. The Si-H bonding was observed in porous 3C-SiC around wavenumber 2100 cm$^{-1}$. PL shows the band gap enegry of thin film(2.5 eV) and porous 3C-SiC(2.7 eV).

• Journal of Korea Foundry Society
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• v.23 no.5
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• pp.268-275
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• 2003

The mechanism of the hydrogen gas pore formation was investigated in Lost Foam Casting of Al-alloy by reduced pressure test and real casting. The hydrogen gas pick-up was affected by the formed gas during the decomposition of polystyrene in addition to the liquid product. It depended on pouring temperature and a proper temperature of metal front gave the minimum hydrogen pick-up. At a low pouring temperature, the hydrogen went into the melt mainly from entrapped liquid product of polystyrene but pores were formed from the gas as well as the liquid product at a high pouring temperature. The mold flask evacuation down to 710torr decreased the gas porosity down by around 0.4% vol%. The entrapped decomposition product of polystyrene in the melt was observed through the visualization of filling behavior of Al alloy-melt with the high speed camera.

• Membrane Journal
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• v.26 no.4
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• pp.310-317
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• 2016

Lithium ion secondary battery (LISB) is an energy conversion system operated via charging-discharging cycle based on Lithium ion migration. LISB has a lot of advantages such as high energy density, low self-discharge rate, and a relatively high lifetime. Recently, increasing demands of electric vehicles have been encouraging the development of LISB with high capacity. Unfortunately, it causes some critical safety issues. It includes dendrite formation on negative electrode, resulting in electric shortage problems and battery explosion. Also, the elevated temperatures occurred during the LISB operation induces thermal shrinkage of polyolefin (e.g., polyethylene and polypropylene) separators. Consequently, the low thermal stability leads to decay of LISB performances and the reduction of lifetime. In this study, sulfonated poly (arylene ether sulfone) (SPAES) random copolymers were used as key materials to prepare polyolefin pore-filling separator. The resulting separators were evaluated in the term of metal ion chelation capability associated with dendrite formation, $Li^+$ ion conductivity and thermal durability.

• Applied Chemistry for Engineering
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• v.20 no.5
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• pp.505-510
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• 2009

It is well known that the properties of concrete such as the compressive strength, water permeability, water tightness and durability are affected by micro-structure in hardened cement paste. Especially, for durability of concrete, watertightness of cementitious materials is the most critical property among various properties. Recently, many types of material such as organic and/or inorganic materials are used for watertightness of concrete. In this study, we examined the effect of fluorine-based emulsion on watertightness property. And we also discussed the change of microstructure and formation of hydrates in hardened cement paste by the addition of fluorine-based emulsion. Cement paste with fluorine-based emulsion showed improvement of watertightness by the surface activation of cement paste and by formation of $CaF_2$ fine crystals in cement pore structure.