• Asian-Australasian Journal of Animal Sciences
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• 제14권10호
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• pp.1429-1433
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• 2001

This study provides electron microscopic evidence for the presence of cellulosome-like structures on the cell surface of Ruminococcus albus F-40. Electron microscopy showed that clusters of tightly packed spherical particles were located on the cell surface of R. albus. The protuberant structures present mainly on the bacterial surface and also bound to the cellulose substrate appeared to be the site of cellulosome-like structures. From the evidence presented, we suggest that the structures described here might be a characteristic feature of some ruminal cellulolytic bacteria.

• 한국의학물리학회지:의학물리
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• 제22권3호
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• pp.117-123
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• 2011

방사광 영상은 내부가 보이지 않는 생물학적 검체의 구조를 관찰하는데 사용될 수 있으며, 조직의 고정이나 염색없이 비침습적으로 조직의 미세 구조를 관찰하는데 유용하다. 본 연구에서는 포항방사광가속기의 1B2 빔라인에서 개발한 경엑스선(hard X-ray) 현미경을 이용하여 11.1 KeV의 에너지에서 인간 유방 조직의 현미경적 영상을 얻고자 하였으며, 고해상도의 영상을 얻기 위해 동심원 회전판(zone plate)과 위상차 영상기법을 사용하였다. 실험 결과 경 엑스선 현미경을 이용하여 유방 섬유낭성변화와 유방암 조직의 방사광 미세 영상을 얻었으며, 이들 영상의 공간 해상도는 60 nm로 각각의 유방 조직의 미세 구조를 관찰하기에 충분하였다. 또한 방사광 미세 영상과 기존의 유방촬영 영상을 비교하였을 때, 방사광 미세 영상에서 각 조직의 특징적인 형태학적 변화가 더 뚜렷하게 나타나는 것을 관찰할 수 있었다. 결론적으로, 경엑스선 위상차 현미경을 이용한 방사광 영상은 유방 질환의 진단에 많은 도움을 줄 수 있을 것으로 생각되며, 임상적으로나 여러 연구 목적으로 유용하게 사용될 수 있을 것으로 기대된다.

• 한국자원식물학회지
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• 제8권3호
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• pp.303-318
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• 1995

금강초롱꽃과 근연분류군 4속 9분류군에 대한 표피 및 화분의 미세구조, 동위효소 분석을 통하여 금강초롱꽃속(屬)이 특산속으로서 구분이 가능한가를 알아보았다. 표피는 미세구조에서는 잎이 표면과 이면세포의 모양, 화피의 세포형태, 종피의 미세구조 등이 속과 종을 구분하는데 유용한 형질로 나타났으며, 화분학적 형질에서는 표면무늬와 전체 형태에 많은 변이가 있어 속내 분류군들의 유집 및 분류가 불가능하였다. 동위효소 분석에서는 분류군에 따라 지역, 집단간 변이가 매우 심하게 나타났지만 금강초롱꽃과 가장 유사한 분류군은 초롱꽃과 섬초롱꽃으로 유집되어 나타났다. 이상의 결과에서 금강초롱꽃속(屬)은 근연 분류군과 표피의 형질, 동위효소 분석등에서 근연 분류군과 뚜렷한 차이가 있어 특산속으로서 잘 구분되었다.

• 한국결정성장학회지
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• 제14권3호
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• pp.115-122
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• 2004

다공성 물질이 건조될 때 입자는 겔 상태의 그물망 구조를 갖는다. 따라서 건조공정 중 발생하는 잔류응력을 정확하게 해석하기 위해서는 공극률과 공극형상에 따른 물성을 알아야 한다. 본 연구에서는 균질화법으로 원형과 십자형의 공극을 갖는 미시적인 겔구조로부터 공극률에 따른 재료의 탄성특성을 예측하고. 다공성 세라믹 애자의 건조공정을 유한요소 해석하였다. 해석 결과, 변형 형상과 온도, 습도 분포는 공극을 고려하지 않은 해석과 유사하지만 잔류응력 값은 큰 차이가 있음을 알 수 있었다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2009년도 제38회 동계학술대회 초록집
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• pp.53-53
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• 2010

Car industry has required light-weight steels, but still with strong mechanical strength. To meet this requirement, a variety of researches on Fe-Al alloys have been performed. As Al is being added in a disordered manner, alloys become more ductile and show higher yield stress. At a certain concentration of Al, however, the Fe-Al alloy system falls in a second phase whose mechanical strength is worsened. To understand the microscopic role of Al, we investigate the stability and the elastic properties of various Fe-Al alloys using ab initio density functional theory. At agiven Al concentration, the equilibrium geometry is obtained among several disordered Fe-Al alloy structures by performing the geometry relaxation. The formation energies and elastic properties such as bulk moduli of the equilibrium structures are also computed as a function of Al concentration. We also investigate the effects of different elements such as Si and Mn. Fe-Si alloy systems exhibit unusual mechanical behaviors requiring further investigation to understand their physical origin. Especially, the microscopic role of Mn is investigated to find its physical origin of preventing the Fe-Al alloy system from forming an unfavorable second phase. The effect of manganese on mechanical properties of Fe-based alloys is also explored.

• Journal of Oral Medicine and Pain
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• 제19권1호
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• pp.45-55
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• 1994

The purpose of this study was to observe the microscopic change of salivary gland tissues, which is the cause of xerostomia in diabetic condition: for this target the author injected STZ 0.1ml/100gm b.w. on rat to produce diabetes, and than observed microscopic change in submandibular gland through the histopathologic method, obtaining as follows : 1. All of the experimental specimens suffered diabetes after injection of STZ, but the blood glucose level was irregular. 2. There were not interrelationship between the blood glucose level and microscopic change on salivary gland tissues. 3. The salivary gland changed after diabetes initiation in lapse of times; after 14 days,suffered severe destruction, however after 17 days, it was regenerated. 4. Salivary glands showed congested, destructive acini cells, and hyperplastic ductal cells as well as salivary gland duct-like structures. 5. Then were accumulation of fat granules within the cytoplasm of the acini cells on mucous gland in diabetic condition. 6. According to insulin injection, there were no more changes on salivary gland tissues, even in the accumulation of fat granules. 7. Histological changes of the serous gland were obvious more than the mucous gland in this experimental condition.

• Applied Microscopy
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• 제44권4호
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• pp.138-143
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• 2014

Transmission electron microscope (TEM) is an excellent tool for studying the structure and properties of nanostructured materials. As the development of $C_s$-corrected TEM, the direct analysis of atomic structures of nanostructured materials can be performed in the high-resolution transmission electron microscopy (HRTEM). Especially, fast Fourier transform (FFT) technique in image processing is very useful way to determine the crystal structure of HRTEM images in reciprocal space. To apply FFT technique in HRTEM analysis in more reasonable and friendly manner, we made a new circular region of interest (C-ROI) FFT script and tested it for several HRTEM analysis. Consequentially, it was proved that the new FFT application shows more quantitative and clearer results than conventional FFT script by removing the streaky artifacts in FFT pattern images. Finally, it is expected that the new FFT script gives great advantages for quantitative interpretation of HRTEM images of many nanostructured materials.

• Journal of Magnetics
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• 제7권3호
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• pp.94-97
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• 2002

The dependence on nickel oxide thickness and a ferromagnetic layer thickness in unidirectional and isotropic exchange-coupled NiO/NiFe(Fe) bilayer films was investigated by magnetic force microscopy to better understand the relation between magnetic domain structure and exchange biasing at microscopic length scales. As the NiO thickness increased, the domain structure of unidirectional biased films formed smaller and more complex in-plane domains. By contrast, for the isotropically coupled films, large domains generally formed with increasing NiO thickness including a cross type domain with out-of plane magnetization orientation. The density of the cross domain is proportional to exchange biasing field, and the fact that the domain mainly originated from the strongest exchange coupled region was confirmed by imaging in an applied external field during a magnetization cycle.

• 대한본초학회지
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• 제22권3호
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• pp.101-107
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• 2007

Objective : This study was carried out to investigate diagnostic difference and anti-oxidative effect of 3 different Anemarrhenae Rhizoma (AR) extracts. Methods : Microscopic examination was used to distinguish histological differences. And eliminative ability of several kinds of free radicals was also measured. Results : In microscopic examination, we can distinguished three different lineage of AR with different structure of vascular bundles and secretory structures. The extract of AR show profitable abilities of elimination of DPPH free radical, ABTS free radical and hydrogen peroxide. Conclusion : So, it can be concluded that AR extract has an anti-oxidative effects. Especially indeciduous lineage was most effective to remove free radicals.

• Bulletin of the Korean Chemical Society
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• 제32권2호
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• pp.498-502
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• 2011

The divergent synthesis of novel phosphorus-containing dendrimer with 4,4'-sulphonyldiphenol at the core has been accomplished involving simple condensation reactions using $P(O)Cl_3$, $P(S)Cl_3$, 3-amino-phenol, 3-hydroxy-benzaldehyde, and 2-butyn 1, 4-diol. The final compound was a Schiff's base macromolecule possessing 4 imine bonds, 8 acetylenic bonds and 8 OH groups at the periphery. The structures of intermediate compounds were confirmed by IR, NMR ($^1H$, $^{13}C$ and $^{31}P$), LC-Mass and C, H, N analysis. The structure of the final dendrimer (5) was confirmed by IR, NMR ($^1H$, $^{13}C$ and $^{31}P$), MALDI-TOF-MS, and C, H, N analysis. The surface morphological characteristics of the final dendrimer were understood by Scanning Electronic Microscopic study (SEM). The thermal stability of the final dendrimer was studied by TGA/DTA analysis.