• Applied Microscopy
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• v.36 no.spc1
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• pp.25-33
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• 2006

Nanofabrication with finely focused ion and electron beams is reviewed, and position and size controlled fabrication of nano-metals and -semiconductors is demonstrated. A focused ion beam (FIB) interface attached to a column of 200keV transmission electron microscope (TEM) was developed. Parallel lines and dots arrays were patterned on GaAs, Si and $SiO_2$ substrates with a 25keV $Ga^+-FIB$ of 200nm beam diameter at room temperature. FIB nanofabrication to semiconductor specimens caused amorphization and Ga injection. For the electron beam induced chemical vapor deposition (EBI-CVD), we have discovered that nano-metal dots are formed depending upon the beam diameter and the exposure time when decomposable gases such as $W(CO)_6$ were introduced at the beam irradiated areas. The diameter of the dots was reduced to less than 2.0nm with the UHV-FE-TEM, while those were limited to about 15nm in diameter with the FE-SEM. Self-standing 3D nanostructures were also successfully fabricated.

• Applied Microscopy
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• v.45 no.1
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• pp.16-22
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• 2015

The reaction kinetics of the growth of Ni germanide in the Ni/Zr-interlayer/Ge system was investigated using isothermal in situ annealing at three different temperatures in a transmission electron microscope. The growth rate of Ni germanide in the Ni/Zr-interlayer/Ge system was determined to be diffusion controlled and depended on the square root of the time, with the activation energy of $1.04P{\pm}0.04eV$. For the Ni/Zr-interlayer/Ge system, no intermediate or intermixing layer between the Zr-interlayer and Ge substrate was formed, and thus the Ni germanide was formed and grew uniformly due to Ni diffusion through the diffusion path created in the amorphous Zr-interlayer during the annealing process in the absence of any intermetallic compounds. The reaction kinetics in the Ni/Zr-interlayer/Ge system was affected only by the Zr-interlayer.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.23 no.4
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• pp.333-340
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• 2013

Objectives: This study was designed to establish an accurate analytical method for asbestos in a biological sample for determining occupational asbestos-related diseases and relief of the health effects of environmental asbestos. Methods: Biological samples were obtained from lungs of rats following intratracheal instillation of asbestos(Chrysotile, anthophyllite) and were prepared according to digestion method(Wet digestion, high temperature ashing, low temperature ashing). The samples were then analyzed for asbestos fibers using a transmission electron microscope equipped with an energy dispersive X-ray spectrometer. Results: Low temperature plasma ashing removed more of the organic components and reduced fiber loss compared to the wet digestion method, making specimens so prepared more suitable for transmission electron microsocpy. Conclusions: The low temperature ashing technique is the most accurate method for analyzing asbestos in biological samples.

• Plant Journal
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• v.16 no.3
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• pp.47-52
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• 2020

This study investigated the methodologies to enhance the corrosion resistance and the ways to measure for subsea equipment made of aluminum. The methodologies for the anticorrosion were cathodic protection, conversion coating, anodizing and organic coating. The simply analyzed ways to measure the corrosion resistance were Scanning Electron Microscope (SEM), Electrochemical Impedance Spectroscopy (EIS), Glow discharge optical emission spectrum spectroscopy (GD-OES), Fourier Transform Infrared Spectroscopy (FT-IR), Transmission Electron Microscopy (TEM), X-ray Photoelectron Spectroscopy (XPS), Scanning Vibrating Electrode Technique (SVET), contact angle and interfacial tension. The most widely used tools for increasing the corrosion resistance were the anodizing and the organic coating. Many ways were evenly used to measure corrosion. The methods more frequently utilized were SEM for the surface investigation and the contact angle to evaluate the corrosion resistance.

• Journal of Welding and Joining
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• v.33 no.2
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• pp.8-13
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• 2015

This study was carried out to evaluate mechanical properties of the jointed Al6061/HT590 alloys by friction stir welding (FSW). FSW was conducted under the conditions with tool rotating speed of 500 RPM and traveling speed of 300 mm/min., where Ar gas was introduced to prevent the materials from corrosion during the welding process. Electron back-scattering diffraction (EBSD) was used to characterize microstructures such as grain size, misorientation angle and crystal orientation. Evolution of intermetallic compounds in Al6061 during the process were examined in terms of morphology, size and aspect ratio at three distinct zones Al base material, heat affected zone and stir zone, where transmission electron microscope (TEM) was used. It was revealed that FSW gave rise to refinement of grains as well as growth of intermetallic compounds in Al6061. The morphological changes of intermetallic compounds exerted an influence on mechanical properties, resulting in occurrence of fracture in the part of the base material instead of the jointed parts (heat affected zone and stir zone). This study systematically evaluated the microstructural evolutions during the FSW for joining Al6061 with HT590 and their effect on mechanical properties.

• Journal of the Korea Convergence Society
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• v.8 no.7
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• pp.123-129
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• 2017

Morphological and ultrastructural characteristics of human hair medulla was investigated with scanning electron microscopy and transmission electron microscopy. The medulla is located in the central position of hair shaft and appear greatly variable forms which discontinuous shape arranged from hair root to apical portion according to longitudinal axis. The thickness of medulla from a single hair presented as very variable in size. The diameter of cross section of human hair medulla measured as $21{\mu}m$ and longitudinal section showed $27{\mu}m$. It grows up to 1/3 from 1/4 in diameter of human hair shaft. It appears emptied hole during separating of macrofibrils in the keratinocyte. The empty space measured $6.5{\mu}m$ in diameter as maximum size and it was filled with air.

• Journal of the Mineralogical Society of Korea
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• v.28 no.4
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• pp.293-297
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• 2015

Focused ion beam (FIB) technique is widely used in the precise preparation of thin slices for the transmission electron microscopic (TEM) observation of target area of the minerals and geological materials. However, structural damages and artifacts by the Ga ion beam as well as electron beam damage are major difficulties in the TEM analyses. TEM analyses of the mineral samples showed the amorphization of quartz and feldspar, curtain effect, and Ga contamination, particularly near the grain edges and relatively thin regions. Although the ion beam damage could be much reduced by the improved procedures including the adjustment of the acceleration voltage and current, the ion beam damage and contamination are likely inevitable, thus requiring careful interpretation of the micro-structural and micro-chemical features observed by TEM analyses.

• Journal of Energy Engineering
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• v.25 no.1
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• pp.192-197
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• 2016

We have surveyed on technical method of fault analysis of semiconductor device. Fault analysis of semiconductor should first be found the places of fault spots. For this process they are generally used the testers; EB(emission beam tester), EM(emission microscope), OBIRCH(optical beam induced resistance change method) and LVP(laser voltage probing) etc. Therefore we have described about physical interpretation and technical method in using scanning electron microscope, transmission electron microscope, focused ion beam tester and Nano prober.

• Applied Microscopy
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• v.25 no.4
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• pp.9-16
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• 1995

Ultrastructure of stemmata(larval eye) of 5th-instar larval in cabbage butterfly, Pieris rapae L, was morphologically investigated with light microscope, scanning electron microscope and transmission electron microscope Six stemmata are on each side of the head. Stemmata V and VI have a Y-shaped sulcus on the surface of their corneal lenses, the others have a columnar shaped process and smooth globular surface. The visual type of stemmata is resembled a single ommatidium of compound eye. The dioptric apparatus are a biconvex shaped cornea and crystalline cone. As a photoreceptor, each stemmata consists of 7 retinular cells arranged into 2 tiers. The first ceil tier of 3 distal retinular cells has formed a V-shaped cup rhabdome and the second cell tier of 4 basal retinular cells has formed a H-shaped fused rhabdome. Each retinular cell filled with pigment granules and contained multivesiclular bodies, coated vesicle and common organelles. The peripheral parts of retinular cells are enveloped by neuroglia cells and retinular cells are surrounded by 3 corneagenous cells. The distal portions of the 3 corneagenous cells contact each other, but the Y-shaped stemmata is separated from each other immediately under the cornea. The 7 axons from each stemma congregate into a bundle and each 7-axon group joins to form a stemmatal nerve, consisting of 42 retinular axons.

• Carbon letters
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• v.13 no.4
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• pp.205-211
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• 2012

Methanol as a carbon source in chemical vapor deposition (CVD) graphene has an advantage over methane and hydrogen in that we can avoid optimizing an etching reagent condition. Since methanol itself can easily decompose into hydrocarbon and water (an etching reagent) at high temperatures [1], the pressure and the temperature of methanol are the only parameters we have to handle. In this study, synthetic conditions for highly crystalline and large area graphene have been optimized by adjusting pressure and temperature; the effect of each parameter was analyzed systematically by Raman, scanning electron microscope, transmission electron microscope, atomic force microscope, four-point-probe measurement, and UV-Vis. Defect density of graphene, represented by D/G ratio in Raman, decreased with increasing temperature and decreasing pressure; it negatively affected electrical conductivity. From our process and various analyses, methanol CVD growth for graphene has been found to be a safe, cheap, easy, and simple method to produce high quality, large area, and continuous graphene films.