• 한국세라믹학회지
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• 제46권1호
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• pp.94-101
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• 2009

The physical properties of artificial aggregates made from clay and inorganic wastes with poor plasticity depends largely on forming method. The artificial aggregates composing of coal fly ash, stone sludge and clay were fabricated using 4 different forming methods and those physical properties were comparatively analyzed. The surface of aggregates made through the extrusion forming process was dense and smooth but was rough for the aggregates obtained by crushing a tile-shaped green body. The aggregates made by pelletizing process had a weak green strength and bumpy surface. The shell generated at surface during a high temperature sintering process induced the most aggregates to be bloated due to a dense shell. But the aggregates made through pelletizing process with dense surface layer showed no significant change in bulk density with sintering temperatures. The water absorption of aggregates decreased with sintering temperature, and that of pelletized specimen was standing $1.8{\sim}2.2$ times higher than that of made by other forming methods. It is concluded that the aggregates having various properties could be fabricated from one batch by using different forming methods.

• 박물관보존과학
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• 제15권
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• pp.122-137
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• 2014

국립중앙박물관 소장의 실록함 ^K976은 조선왕조 선조대의 실록을 보관했던 함으로 장방형 몸체에 뚜껑이 달려있고 표면 전체에 검은색 옻칠이 되어있다. 실록함은 모서리 결구 부분의 짜임이 벌어지고 판재들이 밖으로 휘어지면서 심하게 변형되어 있었고 함의 몸체 상단부의 백골이 부분적으로 결실된 상태였다. 여기에 더하여 뚜껑에는 길이 방향으로 큰 폭의 균열이 발생되어 있었다. 표면의 칠은 곳곳이 들뜨거나 탈락되어 목제 백골이 겉으로 드러난 곳이 많았고 뚜껑을 연결하는 고리쇠 1개가 결실된 상태였다. 국립중앙박물관 보존과학부는 2013년 실록함의 수리 복원 작업에 착수하였으며 이에 앞서 실록함의 구조 양식, 손상 상태, 목제 백골 ^白骨의 수종 분석, 옻칠 기법 등에 대한 조사를 실시하였다. 그 결과 실록함의 목제 백골 재료가 피나무라는 것, 또 실록함 표면에 골회칠 ^骨灰漆 → 종이심 ^紙心, 토회칠 ^土灰漆, 연매 ^煙煤 혼합 흑색칠 → 옻칠이 순차적으로 도장되어 있다는 것을 확인할 수 있었다. 이 실록함은 전통 목칠공예 기술과 재료를 적용한 전면적인 수리 복원을 통해 그 본래의 모습을 되찾게 되었고, 이후 국립전주박물관 역사문화관 개편 전시에서 중요한 전시물로 활용되었다.

• 박물관보존과학
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• 제22권
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• pp.41-52
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• 2019

부여 능산리 서고분군 1, 2호분의 석실내부 벽화의 존재 여부를 확인하기 위하여 육안조사와 현장에서의 현미경 관찰, 형광X선분석을 수행하고, 일부 채취 시료에 대한 X선회절분석을 수행하였다. 그 결과, 1호분은 석벽의 표면 마무리 상태가 거칠고, 현실 천정을 제외한 부위에서는 벽화의 어떠한 흔적도 관찰되지 않았다. 또한 현실 천정에서는 석재와는 다른 색의 흑색 물질이 관찰되는데, 이 부분의 경우에도 표면부와 표면을 살짝 긁어내어 드러난 내부가 동일한 육안적 특징을 보이며, 이 부분에서 채취한 시료에서 흑운모가 주된 광물로 동정되어 먹 등 인위적 물질을 칠한 것이 아니라 석벽의 구성광물인 것으로 확인되었다. 2호분의 경우 내부 동, 서, 북의 석벽 표면에서 백색물질이 관찰되며, 이 물질에 대한 분석 결과 석회(Calcite)로 확인되어 벽화의 존재가 의심되었다. 그러나 석회층이 동벽의 현실입구와 연도부분에 집중되어 있으며, 북벽과 서벽의 경우에는 단지 하부에서만 집중적으로 관찰되었다. 또한 동벽의 현실입구와 연도부분의 석회물질은 그 분포 형태가 도굴 갱으로 유입된 흙이 쌓인 흔적과 상응하고 있어 2호분 내벽의 석회물질은 외부의 흙과 석회가 유입되어 형성된 것으로 판단되었다. 또한 천장과 사면의 석판틈새에서 확인되는 메움 물질은 분석결과 니질의 토양으로 석벽 표면에 존재하는 석회와는 다른 물질로 확인되었다. 만약 벽화를 조성할 목적으로 석벽표면에 석회층을 인위적으로 형성한 것이라면 석판틈새 매움 물질도 석회를 사용하는 것이 더 자연스러웠을 것이다. 이러한 점으로 보아 능산리 2호분의 현실과 연도의 내벽에도 벽화는 없는 것으로 판단된다.

• 한국재료학회지
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• 제14권5호
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• pp.322-327
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• 2004

Copper-based leadframe sheets were oxidized in two kinds of hot alkaline solutions to form brown-oxide or black-oxide layer on the surface. The oxide coated leadframe sheets were molded with epoxy molding compound (EMC). After post mold curing, the oxide-coated EMC-leadframe joints were machined to form sandwiched Brazil-nut (SBN) specimens. The SBN specimens were used to measure the fracture toughness of the EMC/leadframe interfaces under mixed-mode (mode I + mode II) loading conditions. Fracture surfaces were analyzed by various equipment to investigate failure path. The results revealed that the failure paths were strongly dependent on the oxide type. In case of brown oxide, hackle-type failure was observed and failure path lay near the EMC/CuO interface with a little inclining to CuO at all case. On the other hand, in case of black oxide, quite different failure path was observed with respect to the distance from the tip of pre-crack and phase angle. Different failures occurred with oxide type is presumed to be due to the difference in microstructure of the oxides.

• 한국지하수토양환경학회지:지하수토양환경
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• 제15권3호
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• pp.34-43
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• 2010

The fate of hydrophobic organic contaminants (HOCs) in ground water is highly affected by the distribution and property of the carbonaceous materials (CMs) in subsurface sediments. CMs in soils consist of organic matters (e.g., cellulose, fulvic acid, humic acid, humin, etc.) and black carbon such as char, soot, etc. The distribution and property of CMs are governed by source materials and geological evolution (e.g., diagenesis, catagenesis, etc.) of them. In this study, the distribution and property of CMs in subsurface sediments near the Imjin river in the Republic of Korea and HOC sorption property to the subsurface sediments were investigated. The organic carbon contents of sand and clay/silt layers were about 0.35% and 1.37%, respectively. The carbon contents of condensed form of CMs were about 0.13% and 0.45%, respectively. The existence of black carbon was observed using scanning electron microscopes with energy dispersive spectroscopy. The specific surface areas (SSA) of CMs in heavy fraction(HFrCM) measured with N2 were $35-46m^2/g$. However, SSAs of those HFrCM mineral fraction was only $1.6-4.3m^2/g$. The results of thermogravimetric analysis show that the mass loss of HFrCM was significant at $50-200^{\circ}C$ and $350-600^{\circ}C$ due to the degradation of soft form and condensed form of CMs, respectively. The trichloroethylene (TCE) sorption capacities of sand and clay/silt layers were similar to each other, and these values were also similar to oxidzed layer of glacially deposited subsurface sediments of the Chanute Air Force Base (AFB) in Rantoul, Illinois. However, these were 7-8 times lower than TCE sorption capacity of reduced layer of the Chanute AFB sediments. For accurate prediction of the fate of hydrophobic organic contaminants in subsurface sediments, continuous studies on the development of characterization methods for CMs are required.

• Mycobiology
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• 제34권3호
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• pp.148-150
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• 2006

Karoowia saxeti was recorded during the lichen field expedition in southern part of Korea in 2006. The lichen was found on the rock surface along coastal line. This species was easily recognized by chemistry (K+ yellow) and the presence of isidia. Thallus was saxicolous, subcrustose, more or less lobate at the center with clearly lobed margins, $2{\sim}6\;cm$ broad and pale yellowish green. Thalli lobes were irregular, variable, up to 1.0mm wide, not branched, flat to more or less convex and contiguous to subimbricate. Upper surface of the thalli was continuous, emaculate, moderately isidiate. The isidia was subglobose to cynlindrical, darkening at the tips and unbranched. Low surface of the thalii was black with a spongy rhizoidal and lamellar layer. HPLC analysis proved the presence of stictic acid (K+ yellow), norstictic acid and usnic acid. This is the first record of the species in South Korea.

• Restorative Dentistry and Endodontics
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• 제21권1호
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• pp.227-241
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• 1996

The effect of collagen dissolution in acid conditioned dentin was morphologically examined by both scanning and transmission electron microscopy. 18 freshly extracted human molars and dentin bonding systems of All Bond 2, Scotchbond Multipurpose, Superbond D-Liner were used in this study. For SEM preparation, each 3 of ~ exposed dentin surfaces were acid conditioned by using various acids within the above three bonding systems respectively. After acid conditioning of the other 3 exposed dentin surfaces as above, they were treated with 1.7% NaOCl for 2 minutes. The remaining 3 dentin surfaces were acid conditioned and treated with 3.3 % NaOCl for 2 minutes. All of the specimens were then fixed in 4 % glutaraldehyde for 12 h at $4^{\circ}C$ and dehydrated in ethanols grades from 50 % to 100 %, then surface changes of the specimens were observed by using SEM. For TEM preparation, exposed dentin surfaces were acid conditioned with the same acid as SEM specimens and treated with 1.7%, 3.3 % NaOCl respectively, then applied with corresponding bonding agents. After the procedures were finished, composite resin were applied on the dentin surfaces and light cured. Small, rectangular sticks with end dimensions of approximately 1 by 1 mm were sectioned and further sample preparative techniques for transmission electron microscopy were performed in accordance with the procedures used for ultrastructural TEM observations of calcified tissues. The results were as follows : 1. In the 1.7 % NaOCl retreated specimens after acid conditioning, the porous dentin surface of intertubular dentin and wide opening of dentinal tubules were appeared. And there were fine irregularities on the intertubular dentin, indicating a clear difference as compared with the acid conditioned specimens. 2. In the 3.3% NaOCl retreated specimens after acid conditioning, the intertubular dentin was further eroded causing a more porous and wider opening of dentinal tubules. Moreover, sharp irregularities on the intertubular dentin were more evident than those of acid conditioned and 1.7% NaOCl retreated specimens. 3. In all of the acid conditioned specimens, the resin-dentin hybrid layer of approximately 3.5mm thickness was formed and the collapsed collagen layer was observed on the uppermost part of hybrid layer in the specimens applied with All Bond 2. The collgen fibrils of intertubular dentin in specimens applied with Scotchbond Multipurpose were running perpendicular to the interface, and electron dense black layer demarcated from the deep unaltered dentin was more evident in the specimen applied with Superbond D-Liner than any other specimens. 4. In the 1.7 % NaOCl retreated specimens after acid conditioning, the resin-dentin hybrid layer of approximately 2.5-3.0mm thickness was formed and the collapsed collagen layer and longitudinally running collagen fibrils as shown in the acid conditioned specimens were observed in the specimens applied with All Bond 2 and Superbond D-Liner. 5. In all of the 3.3% NaOCl retreated specimens after acid conditioning, the evidence of resin-dentin hybrid layer was not identified ; nevertheless, the longitudinally running collagen fibrils remained slightly in the specimens applied with All Bond 2.

• 보존과학회지
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• 제27권4호
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• pp.451-458
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• 2011

이 연구에서는 문헌조사와 광학적 및 과학적 분석조사를 토대로 송산리 6호분 벽화의 제작기법에 대해 고찰하였다. 연구결과, 송산리 6호분의 전축방식은 공적법이 아닌 모르타르를 이용하여 전(塼)을 축조하였고 줄눈(masonry joint) 재료로 석회, 모래 및 석고를 이용하였다. 전돌 표면에는 전체적으로 흑색을 칠한 다음 백색 회(灰)칠을 하였다. 그 위에 벽화제작을 위한 점토 바탕 층을 조성하였는데 수비가 잘된 점토를 흙손 등의 도구를 이용하지 않고 붓으로 바르듯이 완성하였다. 바탕층에 사용된 점토의 재료적 특성은 $30{\mu}m$ 실트질 크기 이하의 광물입자들로 구성되어 있다. 현재까지 고대의 고분벽화에서 사신도의 채색 부위에만 점토 바탕층을 조성하여 제작된 고분벽화는 송산리 6호분이 유일하다. 이 송산리 6호분은 동양을 비롯한 한국의 다른 벽화에서 볼 수 없는 제작기술이라 할 수 있으며 1933년 발굴 당시에 벽화는 이미 심각하게 훼손된 상태였다고 가정하더라도 종합적으로 볼 때 미완의 벽화라고 추정할 수 있다.

• 보존과학회지
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• 제22권
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• pp.99-108
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• 2008

본 연구는 고구려 벽화고분인 진파리 1, 4호분 벽화의 표면에서 관찰되는 백색과 흑갈색 오염물제거 방안수립을 위해 진행되었으며, 현장 적용실험을 실시하였다. 사전조사에서 금속현미경과 SEM/EDX를 이용하여 백색과 흑갈색 오염물질 시료의 관찰과 성분분석이 실시되었다. 시료에 대한 연구 결과 백색 오염물질은 $CaSO_4$ 혹은 $CaCO_3$로 흑갈색 오염물질은 황산칼슘화합물 혹은 $CaCO_3$와 토양침적물로 추정되며, 백색과 흑갈색 오염물질 제거를 위해 음이온교환수지와 Ammonium bicarbonate를 처리제로 선정하였다. 두 가지 모두 각각의 처리 대상에 대해 양호한 효과를 나타냈으며, 일부 피각형태로 고착화된 오염물질에 대해서는 물리적인 처리법의 병행이 필요한 것으로 확인되었다.

• International Journal of Concrete Structures and Materials
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• 제6권4호
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• pp.247-250
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• 2012

Composites are somewhat more difficult to model than an isotropic material such as iron or steel due to the fact that each layer may have different orthotropic material properties. In finite element literature the asphalt mixes are represented by using rectangular meshes, not the actual picture of their cross-sections. Asphalt aggregate size and distribution in the asphalt concrete sample, aggregate shape, and fractured surface effects are ignored. In this research, the actual image of the sample including all these effects were directly considered in the finite element. The samples, were cut into cross-sections and were scanned. The image-processing toolbox of Labview was utilized in obtaining the rectangular gray images of the scanned images. In the rectangular sample the aggregates were white and the asphalt binders were black. The grayscale images were converted by LABVIEW into the format required by ANSYS as an input file, with the same dimensions. The nodes at the bottom of the model were constrained in both x and y directions. Left and right edges were symmetry and top was free. Certain amount of pressure was applied along the top surface to simulate the tire pressure.