• Applied Chemistry for Engineering
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• v.16 no.1
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• pp.68-73
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• 2005

Porous layered carbon was prepared by interlayer pyrolysis of pyrolysis fuel oil (PFO) using layered silicate template and successive dissolution of template. Particle morphology was plate type with d-spacing of 0.78~0.82 nm and constant interlayer space. Specific surface area was $30{\sim}576m^2/g$ depending upon template type, mixing ratios, pyrolysis temperature and pyrolysis time.

• The Journal of the Petrological Society of Korea
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• v.16 no.3
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• pp.162-179
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• 2007

Macheon Layered Intrusion (MLI) which intruded into Precambrian gneiss complex of the northern Jirisan area, southeastern part of Youngnam (or Sobaeksan) Massif, is a layered mafic-ultramafic complex of Triassic age (ca. 223 Ma). The MLI is divided into Layered Series and Laminated Series. Layered Series is subdivided into Central Zone (Lower Zone) consisting of olivine gabbros and Peripheral Zone (Middle or Upper Zone) consisting of hornblende gabbros based on the type of cumulus texture and the main mafic phase. The Central Zone of Layered Series comprises thinly laminated olivine gabbros and uniform or thickly laminated coarse olivine gabbros which consist of mela-gabbro, troctolite, leuco-troctolite, and anorthositic rocks. Laminated Series is also subdivided into quartz-bearing biotite-pyroxene gabbros and homblende diorite and both have variable amount of interstitial quartz and microcline. Laminated series display moderately to slightly developed igneous lamination which is defined by the planar alignment of lath-shape plagioclases. Chilled margin of quartz-bearing biotite-pyroxene gabbro with surrounding Precambrian gneisses insists shallower intrusion of more felsic cognate magma evolved in the deep a little later. Rocks of Layered Series have orthocumulus to adcumulus olivine, adcumulus to intercumulus plagioclase, and intercumulus to heteradcumulus pyroxene and hornblende. Magmatic modally grading, folding, and cross-lamination are not rarely occurred in thinly layered rocks. These textural characteristics define main mechanisms of the formation of layered and laminated structure in mafic-ultramafic rocks of Macheon Layered Intrusion are gravity settling and in-situ crystallization associated with slumping and density current.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2002.04a
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• pp.342-346
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• 2002

불포화 층상 해안 대수층 내에서의 밀도 의존적 지하수 유동 및 염분 이동에 대한 연구를 위해 하나의 지하수 유동-용질 이동 연동 수치 모델이 제시되었다. 이 수치 모델은 밀도 의존적 지하수 유동 지배 방정식, 염분 이동 지배 방정식 및 농도와 밀도의 관계식, 그리고 유한 요소법에 기초하여 개발되었다. 서로 다른 두가지 성질의 불포화 대수층이 고려되었다. 하나는 사질토층 위에 점토층이 존재하는 층상 대수층이고, 다른 하나는 사질토층과 점토층이 혼합된 두가지 물질로 구성된 균질화된 대수층이다. 수치모델의 결과는 층상 불균질성 (layered heterogeneity)가 해안 대수층 내에서의 밀도의존적 지하수 유동과 염분 이동에 있어서 매우 중요한 역할을 하고 있음을 보여준다. 그러한 층상 불균질성의 효과는 사질토층과 점토층과의 현저한 수리학적 및 수리역학적 성질의 차이에 기인한다 따라서 실제 해안 대수층 내에서 관찰되는 점토층을 적절히 고려하는 것이 보다 합리적고 타당한 해안 대수층내에서의 밀도 의존적 지하수 유동 및 염분 이동 해석을 가능하게 할 것이다.

• Journal of the Mineralogical Society of Korea
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• v.18 no.3 s.45
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• pp.195-204
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• 2005

Interlayered structures of talc and chlorite in the talc deposits of the Yugu area are studied using transmission electron microscope. Packets of chlorite-like layer in talcs or packets of talc-like layer in chlorites are commonly observed. Randomly interlayered features of talc and chlorite are locally observed in some specimens. Reactions observed in the present study include the addition or removal of a brucite-like layer in the interlayer region of the talc or chlorite resulting in the , transformation between a talc and a chlorite layers and breakdown or formation of a talc-like layer resulting in transformation between two talc layer and one chlorite layer. Both reactions are accompanied by a significant change in volume. In addition to these mechanisms, there are two volume conserving mechanisms; the combination of both mechanisms and mutual transformation in a complex manner. Reactions from 2 chlorite layers to 3 talc layers, from 2 chlorite layers + 1 talc layers to 1 chlorite layers + 3 talc layers, and from 3 chlorite layers to 5 talc layers are observed among the complex type mechanisms.

• Applied Chemistry for Engineering
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• v.16 no.3
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• pp.408-412
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• 2005

Porous layered carbon was prepared by interlayer pyrolysis of pyrolysis fuel oil (PFO) using magadiite template and successive dissolution of template. Particle morphology was plate type with d-spacing of approximately 0.7 nm and it had constant interlayer space. Specific surface area was $147{\sim}385m^2/g$ depending upon template type, mixing ratios and pyrolysis time.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.06a
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• pp.213-214
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• 2007

에폭시/마이카는 높은 절연성과 강도, 열 안정성 등으로 인하여 고전압 회전기 고정자 권선의 절연재료로 사용되고 있다. 그러나 최근 청단기기의 등장과 냉난방 부하의 증가로 첨두 부하가 크게 증가하여 발전기 부하변동과 자동 정지횟수가 빈번해지고 있다. 이에 따라 기존에 사용되고 있는 절연재료를 획기적으로 발전시킨 새로운 소재의 개발이 필요하게 되었다. 최근 나노기술은 이러한 기술적 한계를 극복할 수 있는 좋은 대안으로 떠오르고 있다. 그리고 나노 크기의 층상화합물은 기존의 재료에 비해 월등한 전기적, 기계적, 열적 특성을 지닌 것으로 알려져 있다. 본 논문에서는 에폭시 기지에 층상 마이카와 점토를 혼합한 나노복합재료를 제조하여 주파수별, 온도별 유전특성을 살펴보았다.

• Computational Structural Engineering
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• v.18 no.3 s.69
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• pp.7-14
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• 2005

• The Journal of Engineering Geology
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• v.33 no.1
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• pp.69-83
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• 2023

Forest fires increase the risk of subsequent soil erosion and mass movement in burned areas, even under rainfall conditions below landslide alert thresholds, by destroying plants and vegetation and causing changes to soil properties. These effects of forest fires can alter runoff in burned areas by altering soil composition, component minerals, soil water repellency, soil mass stability, and soil fabric. Heat from forest fires not only burns shallow organic matter and plants but also spreads below the surface, affecting soil constituents including minerals. This study analyzed X-ray diffraction and physical properties of topsoil and subsoil obtained from both burned and non-burned areas to identify the composition and distribution of clay minerals in the soil. Small amounts of mullite, analcite, and hematite were identified in burned soils. Vermiculite and mixed-layer illite/vermiculite (I/V) were found in topsoil samples from burned areas but not in those from non-burned areas. These findings show changes in soil mineral composition caused by forest fires. Expansive clay minerals increase the volume of soil during rainfall, degrading the structural stability of slopes. Clay minerals generated in soil in burned areas are therefore likely to affect the long-term stability of slopes in mountainous areas.

• Journal of Korea Soil Environment Society
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• v.3 no.1
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• pp.31-44
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• 1998

The geochemical experiments were carried out to investigate a removal effect of heavy metals in abdndoned metallic mine wastes, and to conceive a treatment techniques of them. In order to prevent contamination, experiment appature was made of acrylic acid resin and polyethylene which resist to acid and alkali. Experiment models are devided into four groups based on the system environments, distribution patterns and a kind of filling materials. The first group is background model(model I ) which is filled with waste only and opened to air. The second one is four layer group which is subdivided into two models, opened and closed systems, and the third mix group which is subdivided into three models based on mixing ratio of filling materials and system environment like a layered group. The forth is composed of two layer model, lower one composed of waste and upper one limestone chips. Solution drained from Model Ishows a high contents of heavy metals on the all terms of experiments. Among the models, however, the closed mix model V and Ⅶ show the most effective removal of heavy metals liberated from wastes. Models having different mixing ratios of filling materials on closed systems does not affect in heavy metal removal effect. But, the distribution patterns of filling materials affect very much on removal effect of heavy metals. The closed models with same constitution ratios and distribution patterns of filling materials show more and less effective removal to the open models.

• Transactions of the Korean Society of Automotive Engineers
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• v.3 no.1
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• pp.65-75
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• 1995

The present study was investigated combustion characteristics of methane-air mixtures at stratified charge in a constant volume combustion chamber. The results indicated that even the vety lean mixture, which is normally not flammable in single chamber type, could be burned within. a comparatively short time by using sub-chamber with stratified charge method. And the lean inflammability limit of mixture in a main chamber was about ($\phi_m$cr=O.46, when the equivalence ratio of a sub-chamber was $\phi_s$= 1.0. Initial time of pressure increase and total burning times were decreased and maximum combustion pressure. was increased as the equivalence ratio of both sub and main chamber approached unity. Specifically, initial time of pressure increase and total burning times were greatly affected rather by. the equivalence ratio of sub-chamber than that of main chamber. The maximum combustion pressure was little affected if the total equivalence ratio lies in the same range.