• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회A
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• pp.1288-1293
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• 2007

The present study covers the design and analysis of a thermionic scanning electron microscope (SEM) column. The SEM column contains an electron optical system in which electrons are emitted and moved to form a focused beam, and this generates secondary electrons from the specimen surfaces, eventually making an image. The electron optical system mainly consists of a thermionic electron gun as the beam source, the lens system, the electron control unit, and the vacuum unit. In the design process, the dimension and capacity of the SEM components need to be optimally determined with the aid of finite element analyses. Considering the geometry of the filament, a three-dimensional (3D) finite element analysis is utilized. Through the analysis, the beam emission characteristics and relevant trajectories are predicted from which a systematic design of the electron optical system is enabled. The validity of the proposed 3D analysis is also discussed by comparing the directional beam spot radius. As a result, a prototype of a thermionic SEM is successfully developed with a relatively short time and low investment costs, which proves the adoptability of the proposed 3D analysis.

• Tribology and Lubricants
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• 제7권2호
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• pp.61-66
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• 1991

The frictional and wear characteristics of non-asbestos friction materials made of four different fibers (carbon, aramid, ceramic and glass) have been investigated at elevated temperature using High Frequency Friction Tester. On the basis of the experimental results, friction and wear phenomena of four different non-asbestos fibers were caused by lattice layer film of carbon, polymeric transfer film of aramid, abrasion of ceramic and adhesion of glass fiber under each contact junction. The surface analysis of the worn specimens and counter parts after tests were observed using Scanning Electron Microscope and Optical Microscope.

• Mycobiology
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• 제30권4호
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• pp.193-196
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• 2002

Five species of the genus Xylaria are recognized on Malaysia materials: X. hypoxylon(L. FR.) Grev, X. allantoidea(Berk.) Fr., X. cubensis(Mont.) Fr., X. curta Fr. and X. grammica(Mont.) Fr.. The collection of Xylaria allantoidea from Malaysia is compared to the collection from Taiwan in morphological characters. The species are described their the host and cultural characteristics by a bright microscope and a scanning electron microscope.

• Journal of the Korean Wood Science and Technology
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• 제15권3호
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• pp.24-33
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• 1987

This study was executed to investigate scanning electron microscopic characteristics of Korean Rhus lacquer coats. With the unrefined coat, distilled water, sodium hydroxide, acetic acid, ethyl alcohol, cold-check test, and accelerated weathering were performed after refining treatment. These treated lacquer coats were discussed through observation by scanning electron microscope and the obtained results were summarized as follows: 1. Compared with unrefined coat, the refined coat of Korean Rhus lacquer showed more even surface with regular distribution of dispression. 2. Korean Rhus lacquer coat heated at $120^{\circ}C$ for 3 hours revealed no observable difference irrespective of refining and unrefining. 3. Korean Rhus lacquer coat treated by distilled water, sodium hydroxide, acetic acid. ethyl alcohol, cold-check test. and ultraviolet radiation showed significant characteristics compared with untreated coat. Especially. large deformation and checkings were observed by cold-check test and ultraviolet radiation respectively. 4. The Korean Rhus lacquer coat radiated by ultraviolet ray showed 0.11 duller and 1.41 brighter than non-radiated coat through color difference calculator.

• 대한본초학회지
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• 제35권1호
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• pp.9-18
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• 2020

Objectives : We tried to establish standards for genuine by discriminating 3 kinds of pollen and spore herbs that are highly to be mixed with each other. Using an scanning electron microscope, we prepare a standard for discriminating external morphological characters of minute herbs, thereby contributing to the stable supply of genuine herbal medicines. Methods : Standard samples were confirmed by literature review on external morphological characteristics of original plants and herbal medicines, and collection and identification of original plants. The herbal medicines on the market were purchased and classified with using naked eye observation and magnifier. Finally, micromorphological identifications were conducted using an scanning electron microscope. Results : 1. Pini Pollen was clearly distinguished by its relatively medium size and a pollen grain with two swollen reticulate sacci at both ends. The verrucate ornamentation on the exine surface of the corpus and a sunken leptoma germ pore may be used as a discrimination criteria. 2. Typhae Pollen was distinguished by its relatively small size and a saccus on the end of a pollen grain. Reticulate ornamentation of exine surface of the corpus, and a slightly clear ulcerate germ pore can be used as a discrimination criteria. 3. Lygodii Spora was distinguished by its relatively large triangular-ovate shape and trichotomous fissure. Verrucate-tuberculate ornamentation of exine surface and trilete aperture could be used as a discrimination criteria. Conclusion : These results indicate that the use of electron microscopy is very effective for discriminating the external morphology of minute herbal medicines.

• 대한기계학회논문집A
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• 제26권6호
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• pp.1159-1168
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• 2002

Power-transmission Nylon pinions against steel gears fur different pitch line velocities was studied with a power circulating gear test rig under unlubricated condition by SEM(Scanning Electron Microscope). The wear characteristics of Nylon pinions varied significantly with the pitch line velocity and applied load. Wear occurred most severely at the regions including pitch circle and root circle of Nylon pinions. It is confirmed that Nylon pinions are able to be used fer power-transmission under limited conditions.

• Design & Manufacturing
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• 제14권1호
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• pp.56-62
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• 2020

An electron beam was used to mainly utilize for polishing, finishing, welding, a lithography process, etc. Due to the high technical level of difficulty of high-power density electron beam, it is difficult to secure related technologies. In this study, research was carried out to improve the machinability by developing the vaporized amplification sheets to realize the electron beam drilling technology. Their vaporized amplification sheets were analyzed by using the measurement of chemical and composition, which is such as TGA, SEM. We analyzed micro-hole processing using a microscope. Also, the thermal characteristics of vaporized amplification sheets are highly significant for applying to high-power density electron beam technique. So, we finished the vaporized amplification sheets according to the process conditions and analyzed it according to the machining conditions of the electron beam. It was confirmed that the effect on the experimental results differs depending on the influence of the metal powder contained in the developed material.

• 한국균학회지
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• 제27권1호통권88호
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• pp.73-75
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• 1999

Three species of the genus Xylaria are recognized on Taiwan materials: X. allantoidea (Berk.) Fr. and X. obovata (Berk.) Fr.; including one new record X. curta Fr., having $9.0-10.8{\times}3.9-5.4\;{\mu}m$ ascospores, in Taiwan. The collection of Xylaria allantoidea from Taiwan is compared to other collections in morphological characters. The species are described from the host and in culture by a bright microscope and a scanning electron microscope.

• 전자공학회논문지D
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• 제35D권9호
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• pp.42-47
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• 1998

현재의 전자빔 묘화의 한계를 극복할 수 있는 마이크로 전자빔 시스템의 전자 광학 렌즈를 제작하였고 전자빔 묘화실험을 통하여 이를 검증하였다. 마이크로머시닝기술을 이용하여 실리콘 전극을 제작하고 이를 양극 접합을 통해 조립하여 다층 전극의 전자 광학 렌즈를 제작하였다. 완성된 전자 광학 소자를 초고진공 챔버에 장착하여, STM(Scanning Tunneling Microscope) 팁에서 방출된 전자빔의 focusing 특성을 관찰하였으며 전자를 집속하여 리소그라피를 수행하였다. E-beam 감광막은 PMMA(Poly-methylmethacrylate)를 사용하였고 0.13㎛의 패턴을 형성시킬 수 있었다.

• Tribology and Lubricants
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• 제18권4호
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• pp.260-266
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• 2002

In this study, the effects of oxide layer farmed on the wear tracks of TiN coated silicon wafer on friction and wear characteristics were investigated. Silicon wafer was used for the substrate of coated disk specimens, which were prepared by depositing TiN coating with 1 ${\mu}{\textrm}{m}$ in coating thickness. AISI 52100 steel ball was used fur the counterpart. The tests were performed both in air for forming oxide layer on the wear track and in nitrogen to avoid oxidation. This paper reports characterization of the oxide layer effects on friction and wear characteristics using X-ray diffraction(XRD), Auger electron spectroscopy(AES), scanning electron microscopy (SEM) and multi-mode atomic force microscope(AFM).