• 한국공작기계학회논문집
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• 제17권5호
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• pp.52-57
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• 2008

Most of the electrons emitted from the filament, are captured by the anode. The portion of the electron current that leaves the gun through the hole in the anode is called the beam current. Electron beam probe is called the focused beam on the specimen. Because of the lenes and aperture, the probe current becomes smaller than the beam current. It generate various signals(backscattered electron, secondary electron) in an interaction with the specimen atoms. Backscattered electron provide an useful signal for composition and local specimen surface inclination. Secondary electron is used far the formation of surface imagination. The steady electron beam probe is very important for the imagination formation and the brightness. In this paper, we show the results of developed elements that create electron beam probe and the measured beam probe in various acceleration voltages by Faraday cup. These data are used to analysis and improve the performance of the system in the development.

• 한국진공학회지
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• 제4권S1호
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• pp.28-33
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• 1995

TiN 박막은 저온(<$500^{\circ}C$), 저압(1Torr)에서 Tetrakis(diethylamido)titanium[TDEAT, Ti(NEt2)4]single precursor를 사용하여 증착하였다. 증차고딘 박막은 SEM(Scanning Electron Microscopy)으로 surface morphology와 step coverage를 측정하였고, TEM(Transmission Electron Microscopy)분석결과 microcrystalline의 TiN을 확인하였다. XPS(X-ray Photoelectron Spectroscopy)분석결과에 따르면 $200-500^{\circ}C$구간에서는 $\beta$-hydogen elimination에 의한 반응이 일어나고 $600-700^{\circ}C$구간에서는 thermal decomposition에 의한 반응이 일어나고 있음을 알 수 있다. Carbon과 oxygen의 농도는 AES(Auger Electron Spectroscopy)를 사용하여 측정하였으며 온도가 감소할수록 carbon의 농도가 감소하는 경향을 보여주고 있다.

• Applied Microscopy
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• 제10권1_2호
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• pp.27-32
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• 1980

중동지방에 다녀온 48세의 한국인 남자 피부에 발생한 leishmania증 1예에 대하여 광학 및 전자현미경적 관찰을 하여 문헌 고찰과 아울러 보고하였다. 광학현미경적으로는 조직구 침윤을 주로 하는 만성 육아종성염증반응을 보였고 Giemsa염색상 다수의 leishmania충체를 조직구내에서 관찰할 수 있었다. 전자현미경적으로는 난원형의 단세포 또는 분열중인 충체가 조직구내에 존재하였고 충체는 이중막으로 싸였으며 그 바로밑에 microtubule이 배열되고 세포질내에는 신장된 mitochondrion내에 kinetoplast가 존재하고 그 전방에 flagella가 위치하였으며 기타 다수의 ribosome과 드물게 Golgi complex등을 관찰할 수 있었다. 이와같은 특징은 Leishmania tropica의 promastigote stage와 일치하였다. Leishmania증은 원칙적으로 열대병이나 열대지방과의 접촉이 빈번함에 따라 앞으로 우리나라에서도 보다 많은 증예가 발생할 것으로 사료된다.

• Journal of the Korean Wood Science and Technology
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• 제30권3호
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• pp.48-58
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• 2002

This study was carried out through scanning electron microscopy to elucidate the mechanism of thickness swelling in wood particle-polypropylene composite which is a typical way of using wood and plastic materials. For this purpose, control particleboards and nonwoven web composites from wood particle and polypropylene fiber formulations of 100:0, 70:30, 60:40, and 50:50 were manufactured at target density levels of 0.5, 0.6, 0.7, and 0.8 g/cm³. Their water absorption and thickness swelling were tested according to ASTMD 1037-93 (1995). To elucidate thickness swelling mechanism of composite through the observation of morphological change of internal structures, the specimens before and after thickness swelling test by 24-hour immersion in water were used in scanning electron microscopy. From the scanning electron microscopy, thickness swelling of composite was thought to be caused by the complicated factors of degree of built-up internal stresses by mat compression and/or amount of wood particles encapsulated with molten polypropylene fibers during hot pressing. In the composites with wood particle contents of 50 to 60% at target densities of 0.5 to 0.8 g/cm³ and with wood particle content of 70% at target densities of 0.5 to 0.7 g/cm³, thickness swellings seemed to be largely dependent upon the restricted water uptake by encapsulated wood particles with molten polypropylene fibers. Thickness swelling in the composite with wood particle content of 70% at target density of 0.8 g/cm³, however, was thought to be principally dependent upon the increased springback phenomenon by built-up internal stresses of compressed mat.

• Applied Microscopy
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• 제45권4호
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• pp.225-229
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• 2015

Transition metal dichalcogenides (TMDs) are a class of two-dimensional (2D) materials that have attracted growing interest because of their promising applications. The properties of TMDs strongly depend on the crystalline structure and the number and stacking sequence of layers in their crystals and thin films. Though electrical, mechanical, and magnetic studies of 2D materials are being conducted, there is an evident lack of direct atom-by-atom visualization, limiting insight on these highly exciting material systems. Herein, we present our recent studies on the characterization of 2D layered materials by means of aberration corrected scanning transmission electron microscopy (STEM), in particular via high angle annular dark field (HAADF) imaging. We have identified the atomic arrangements and defects in 2H stacked TMDs, 1T stacked TMDs, distorted 1T stacked TMDs, and vertically integrated heterojunctions of 2D TMDs crystals.

• Applied Microscopy
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• 제43권3호
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• pp.117-121
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• 2013

Mitochondrion is an important intracellular organelle controlling energy production essential for cell survival. In addition, it is closely related to cellular apoptosis and necrosis. Linear, branched, circular, and ball-shaped mitochondria have been reported. Recent research suggests that mitochondrial morphology may reflect functional status of the cell. In this study, we investigated the density and ratio of the each morphological categories of mitochondria in a few normal cultured cells; astrocyte, HeLa and COS7 cells, of which metabolic activities are different, with high voltage electron microscopy. The absolute number and relative number per unit area of mitochondria was largest in astrocyte. But, the proportion of different mitochondrial shape was similar among cells. These results shows the numerical profiles but not morphological profiles of mitochondria are related to the metabolic activity of each cell line.

• Applied Microscopy
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• 제45권2호
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• pp.95-100
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• 2015

The in-situ heating transmission electron microscopy experiment allows us to observe the time- and temperature-dependent dynamic processes in nanoscale materials by examining the same specimen. The temperature, which is a major experimental parameter, must be measured accurately during in-situ heating experiments. Therefore, calibrating the thermocouple readout of the heating holder prior to the experiment is essential. The calibration can be performed using reference materials whose phase-transformation (melting, oxidation, reduction, etc.) temperatures are well-established. In this study, the calibration experiment was performed with four reference materials, i.e., pure Sn, Al-95 wt%Zn eutectic alloy, NiO/carbon nanotube composite, and pure Al, and the calibration curve and formula were obtained. The thermocouple readout of the holder used in this study provided a reliable temperature value with a relative error of <4%.

• 한국식물병리학회:학술대회논문집
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• 한국식물병리학회 2005년도 추계 학술발표회
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• pp.15-20
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• 2005

Locations of silicon accumulation in rice leaves and its possible association with resistance to rice blast were investigated by analytical electron microscopy and atomic force microscopy. A blast-susceptible cultivar, Jinmi, and partially resistant cultivars, Hwaseong and Suwon345, were grown under a hydroponic culture system with modified Yoshida's nutrient solution. Electron-dense silicon layers were frequently found beneath the cuticle in epidermal cell walls of silicon-treated plants. Increasing levels of silicon were detected in the outer regions of epidermal cell walls. Silicon was present mainly in epidermal cell walls, middle lamella, and Intercellular spaces within subepidermal tissues. Furthermore, silicon was prevalent throughout the leaf surface with relatively small deposition on stomatal guard cells in silicon-treated plants. Force-distance curve measurements revealed relative hardness and smaller adhesion force in silicon-treated plants (18.65 uN) than control plants (28.39 uN). Moreover, force modulation microscopy showed higher mean height values of elastic Images In silicon-treated plants(1.26 V) than in control plants (0.44 V), implying the increased leaf hardness by silicon treatment. These results strongly suggest that silicon-induced cell wall fortification of rice leaves may be closely associated with enhanced host resistance to blast.

• Applied Microscopy
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• 제21권1호
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• pp.86-107
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• 1991

An experimental study was performed to observe the early effects of monocrotaline on pulmonary vascular system by means of light microscopy and scanning electron microscopy, attempting to expore the mechanism behind the process of pulmonary hypertension. Experimental animal(Sprague-Dawley male rats ; 150-200g B. W.) were intra-peritoneal administered with 100mg/kg B. W. monocrotaline. Authors observed light microscopically various gradational increase of wall thickness in pulmonary muscular and non-muscular arteries in duration from 2 weeks to 5 weeks after monocrotaline administration and the changes were more sever in the latter than the former. The scanning electron microscopy shows severe and diffuse endothelical cell swelling, microvilli and microbleb formation since 1 hour after monocrotaline administration and during the course, after 5 hours the severity of endothelial cell damage was prominent with presence of fibrin, webs, platelet thrombi and white cell adherence. It was concluded that the monocrotaline primarily induced severe and diffuse endothelial cell damage of pulmonary arteries and laterly added the participation of platelets, which attributed to the pathogenesis of monocrotaline induced pulmonary vascular lesions in relation to pulmonary hypertension.

• Applied Microscopy
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• 제5권1호
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• pp.1-8
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• 1975

These studies were carried out the observation of polymorphonuclear leukocyte phagocytosis of Candida albicans in vitro and also detected to the cytoplasmic changes of polymorphonuclear leukocyte during phagocytosis by the method of electron microscopy. The results were summarized as follows: 1. In normal polymorphonuclear leukocyte, nuclear lobes showed a preponderance of dense, granular chromatin located peripherally. The cytoplasm of polymorphonuclear leukocyte was not extensive; the cytoplasmic matrix was moderate dense and of a granular appearance. Golgi complex and rough endoplasmic reticulum system was poorly developed. But a various type of granules were seen abundantly. 2. After 30 minutes of incubation, Candida albicans was completely engulfed. These had come to lie in the vacuole which was limited by the membrane. 3. After 90 minutes of incubation, the phagocytic vacuoles were larger, and many granules devoid of membranes were seen within them. Though the granules has lost their membrane after entering the vacuoles. 4. After 2 hours of incubation, the cytoplamsic components of polymorphonuclear leuko cytes were changed their original morphology.