• Proceedings of the Korean Environmental Sciences Society Conference
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• 2017.10a
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• pp.51-51
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• 2017

• Proceedings of the Korean Institute of Industrial Safety Conference
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• 1998.11a
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• pp.173-177
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• 1998

In this paper, we reported an outbreak of fire hazard of ballast for fluorescent lamp. The surface structure and composition of ballast coil analyzed by using metallurgical microscope, scanning electron microscope(SEM) and energy dispersive x-ray spectroscopy(EDX). The surface of molten mark appeared columnar structure and void. EDX analysis indicated that the molten mark spectra were composed not only of the corresponding original spectra but also of several new lines.

• Journal of the Korean Geotechnical Society
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• v.31 no.12
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• pp.17-27
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• 2015

In this study, we tried to precipitate calcium carbonate with carbonate ions decomposed from urea by plant extract and calcium ions dissolved in water. The clay particles carry a net negative charge on their surfaces. Such clay mineral was additionally mixed as a medium to improve soil strength and durability with environmentally-friendly way. The $1^{st}$ solution (plant extracts and urea) and the $2^{nd}$ solution (calcium chloride and clay) were mixed together with clean Nakdong River sand. Then, this mixed soil was compacted into a small cylindrical specimen and then air cured for 7 days in laboratory. The molar concentration of urea and calcium chloride was tested for three different conditions, 1, 5, and 7 mol. Three different clay contents (0, 1, and 3% per total weight) were mixed with sand. For each specimen, a series of unconfined compression test, a durability test, SEM, EDX and XRD analyses were carried out to evaluate its cementation and structure. As the molar concentration of the solution and clay content increased, the unconfined compressive strength and durability increased. The results of SEM, EDX and XRD analyses showed that calcite was precipitated around clay mineral. The thermogravimetry analysis indicated that calcium carbonate precipitated about 1~2% per total weight of the sample.

• Korean Chemical Engineering Research
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• v.47 no.6
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• pp.688-694
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• 2009

A spray-type cleaning agent in utilizing dust-remover on PCB was chosen to study the cleanliness test and efficiency. In order to choose alternative environmental-friendly cleaning agents, it is important that the systematic selection procedures should be introduced and applied through the evaluation of their cleaning ability, environmental characteristics, and economical factors, and that the objective and effective evaluation methods of cleanliness should be established for the industry. A novel cleaning evaluation method with scanning electron microscopy/energy-dispersive X-ray analysis of surface observation evaluation method and an infra-red thermography camera(THERMOVISION A20 model) was studied in this work. The sound card(CT-2770 model) cut by $2{\times}2cm$ size was used as a part, and before and after the spray cleaning, the cleanliness was observed by the image analyzer of SEM and further the removal efficiency of dust was quantitatively evaluated by the component analysis of EDX. For the parts of P4TE model motherboard and IPC-A-36 PCB plate, before and after the spray cleaning, temperature differences were measured and compared at room temperature and 50 oven temperature by an infra-red thermography camera in the contaminants of dust and iron powder.

• Journal of the Korean Geotechnical Society
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• v.28 no.6
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• pp.53-61
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• 2012

The purpose of this study is to understand the mechanism of cementation of soil induced by bacteria. In order to understand the mechanism of cementation of soft soils treated with bacteria, six types of specimens(Not treated, Normal concentration bacteria treatment, High concentration bacteria treatment, Supernatant high concentration bacteria treatment, Double high concentration bacteria treatment, and 25% Specimen high concentration bacteria treatment) were made. Scanning Electron Microscope (SEM), EDX and X-ray diffraction (XRD) analyses were performed on the soft silt and loose sand specimens. Compared with the normal bacteria concentration treated specimen, a clearer cementation between particles was observed in the 25% specimen high bacteria concentration treated specimen. On the basis of the preliminary results, it appears that microbial cementation can occur in the soft soil.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.8
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• pp.2015-2020
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• 2009

$NO_x$ reduction of stationary exhaust was performed at atmospheric condition and the temperature ranging from $200^{\circ}C$ to $500^{\circ}C$ over ZSM-5 supported metal catalyst. The characteristics of the prepared catalysts were investigated using the analytical techniques such as SEM, XRD, EDX, ICP and ITR. The results of EDX and ICP analysis demonstrated that the most part of transition metal existed on the exterior surface of support. Maximum de-$NO_x$ yield over Fe/ZSM-5 shown between $380^{\circ}C$ and $400^{\circ}C$ was presumed to be due to the maximum H2 reduction rate at $400^{\circ}C$ of ITR.

• Analytical Science and Technology
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• v.22 no.3
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• pp.254-262
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• 2009

Activated carbon fiber treated with iron compound (Fe-ACF) was employed for preparation of Feactivated carbon fiber/$TiO_2$ (Fe-ACF/$TiO_2$) composite catalysts. Then, the prepared Fe-ACF/$TiO_2$ composite catalysts were characterized by employing BET, SEM, XRD and EDX instruments. It showed that BET surface area was related to adsorption capacity for each composite. The SEM results showed that ferric compound and titanium dioxide were distributed on the surfaces of ACF. The XRD results showed that Fe-ACF/$TiO_2$ composite mostly contained an anatase structure with a Fe mediated compound. EDX results showed the presence of C, O, and Ti with Fe peaks in Fe-ACF/$TiO_2$ composites. From photocataytic degradation effect, it was observed in the organic dye (Methylene blue, MB) degradation by these composites. Different degradation effect can be attributed to the synergetic effects of photo-Fenton reaction of Fe. It was considered that the combined reactions of Fe-ACF/$TiO_2$ produce powerful photo-Fenton process in the MB degradation.

• Applied Chemistry for Engineering
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• v.19 no.1
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• pp.117-121
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• 2008

In this study, thin YSZ film was prepared by electrostatic spray deposition. The morphology of thin film was strongly influenced by precursor solution and substrate temperature. Especially, dense YSZ film was obtained at the substrate temperature of $400^{\circ}C$. The YSZ film growth rate was $12{\mu}m/h $ at the optimum conditions. Product film was characterized by XRD, FE-SEM and EDX.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.59 no.2
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• pp.232-237
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• 2010

Fault rate of RCD is increasing due to deterioration and long period usage in domestic. According to Korean standards, the RCDs are installed in panel boards. When RCDs are installed at outdoor, the RCDs must be protected from uv, water etc. by using the housing. However, many RCDs are exposed to the external environment. As a results, many RCDs have malfunctions so that cause the electrical accidents. The RCDs manufactured by four makes were used as the sample to weathering test. Futhermore, those were analyzed the ingredients of RCD'S using SEM, EDX and FT-IR/TAR before and after weathering test.

• Journal of Korean Society for Atmospheric Environment
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• v.16 no.6
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• pp.565-572
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• 2000

To quantitatively estimate mass contribution of long-range transported yellow sand, their sources should be separated independently from various local soil sources having similar elemental compositions. While it is difficult to estimate total mass loadings of pure yellow sand by traditional bulk analysis, it can be clearly solved by an particle-by-particle analysis. To perform this study, two yellow sand samples and three local soil samples were collected by a mini-volume sampler. These samples were three analyzed using a scanning electron microscope(SEM) equipped with an energy dispersive x-ray analyser (EDX) was used to obtain basic chemical information of individual yellow san particles. A total of 19 elements in a single particle were measured to develop a source profile with newly created homogeneous particle classes (HPCs) as chemical variables. The present study showed that the yellow sand samples as well as three local soil samples were characterized with reasonably well created HPCs. Finally the mass fraction of each HPC in each sample was calculated and then compared each other.