• Journal of the Korean Society of Food Science and Nutrition
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• v.38 no.9
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• pp.1284-1288
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• 2009

Identification of various inorganic compound crystals contained in solar salts, which are produced from 12 areas of Jeonnam, was firstly made by the X-ray diffraction (XRD) technique. The analysis of the XRD spectra was carried out on the basis of Joint Committee on Powder Diffraction Standards (JCPDS) data and the results of Energy Dispersive X-ray Spectrometer (EDX) measurements. In particular, the analysis of the XRD spectra supported that each solar salt contains $Na_2S$ (Shinan Jeungdo and Sinui), $KMgCl_3$ (Shinan Bigeum), $Ca(ClO_3)_2$ (Shinan Docho), $CaAl_4O_7$ (Haenam Songji), $CaSiO_3$ and $CaCl_2$ (Goheung) as inorganic compound crystals, which have not been reported for the solar salts. Also, the XRD results indicated that the solar salts maintain a cubic NaCl crystal structure without any change of lattice parameters etc. However, it was shown in the Field Emission Scanning Electron Microscope (FE-SEM) images that an external form of the solar salts has a lamination layer shape of a cubic structure, which is different from a simple cubic form for the purified salts and the reagent NaCl.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.49 no.1
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• pp.8-12
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• 2000

The properties variation by deterioration of the 600V grade heat-resistant polyvinyl chloride insulated wire(HIV) was analyzed. The weight variation of the thermal deteriorated HIV was about 42% at 80$0^{\circ}C$ and over. From the analysis result of the metallurgical microscope photographs it shows that the sorface of normal wire showed the elongated structures. However the elongated structures did not appear at $900^{\circ} and over and we could observe that particles were grown. The grown oxidized substances in the thermally deteriorated electric wire were observed by SEM. The CuL, CuK, $CuK_b$, OK and CIK spectra of the thermally deteriorated HIV at $300^{\circ}C$ were uniform regardless of the scanning length, but the spectra of CIK could not found at above $700^{\circ}. At the DTA analysis, the endothermic reactions were occurred around $3006{\circ}C\; and\; 400^{\circ}C$ and the exothermic reactions were occurred around $470^{\circ}, respectively.

• 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.

• Proceedings of the KIEE Conference
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• 2002.07c
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• pp.2000-2002
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• 2002

신장병의 조기진단을 위해서 체내의 요소 농도의 정확한 측정은 매우 중요하며, 이러한 이유에서 많은 연구자들은 보다 빠르고 정확한 체내의 요소농도 측정을 위한 바이오센서를 개발 중이다. 본 논문은 반도체 공정을 이용하여 산화막(4.000${\AA}$)이 성장된 p-형 실리콘 웨이퍼를 사용하였다. RF sputter를 사용하여 티타늄과 백금을 증착한 백금 박막전극을 제작하였다. 그 위에 전도성 고분자인 Polypyrrole(PPy)과 전도도를 증가시키기 위하여 구리를 도펀트로 사용 scan rate 40mV/S $0.8{\sim}-0.8V$ 전위영역에서 산화적 전기 중합법 (anodical electropolymerization)을 이용하여 전극을 형성하였다. 요소를 2개의 암모늄 이온과 1개의 탄산 이온으로의 가수분해반응을 촉매하는 효소로써 유레이즈(urease)를 전기적 흡착방법을 이용하여 고정화하고 이에 요소농도의 변화에 대하여 시간대 전류법 (chronoamperometry:CA)을 사용하여 감도를 측정하였다. 최적화된 조건하에서 요소농도에 비례하여 Cu-doped PPy electrode로부터 얻어진 확산한계전류는 $4.5{\mu}A$/decade의 기울기를 나타내었다. 전극의 표면은 SEM(Scanning Electron Microscopy)과 EDX(Energy Dispersive X-Ray Spectrometer)를 이용하여 분석 하였다.

• Journal of the Korean institute of surface engineering
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• v.42 no.1
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• pp.47-52
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• 2009

Cu-Ag powder having Core-Shell structure was prepared from by electroless plating method using agents such as $AgNO_3$, $NH_{4}OH$, Hydroquinone. Ag coated copper powders were analyzed using scanning electron microscopy(SEM) and energy dispersive X-ray spectrometer(EDX). The silver coating layer of copper powder was affected from various reaction conditions such as molar ratio of $NH_{4}OH$, $AgNO_3$, and pulp density. Free silver was generated below 0.1M or 0.3M and above of $NH_{4}OH$ mole ratio. Silver coating layer thickened as addition of $AgNO_3$. When the pulp density reached 12% with 0.2M $NH_{4}OH$, and 0.15M $AgNO_3$ at $4^{\circ}C$, silver was homogeneously distributed around the copper particles and free silver particles were not generated.

• Korean Journal of Metals and Materials
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• v.46 no.2
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• pp.105-110
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• 2008

Process of the hydroxyapatite (HA) formation on bioactive titanium metal prepared by NaOH treatment in a modified-simulated body fluid (mSBF) containing bovine serum albumin (BSA) was investigated by high resolution transmission electron microscope attached with energy dispersive X-ray spectrometer (EDX). The amorphous titanate, which was formed on titanium surface by NaOH treatment, combined with the calcium ions in the liquid to form an amorphous calcium titanite. With increasing of soaking time in the liquid, an amorphous calcium titanite combined with the phosphate ions to form an amorphous calcium phosphate with low Ca/P atomic ratio, and it grows as aggregates of plate (or needle)-like substance on titanium surface. The crystalline apatite layers, which are needle-shaped with the c axis parallel to the long axis, are formed in an amorphous calcium phosphate with further increase in soaking time. The formation of needle-shaped apatite layers can be explained by electrostatic effects and difference of concentration between calcium, phosphate, and albumin ions.

• Geomechanics and Engineering
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• v.18 no.4
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• pp.427-437
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• 2019

Waste materials are being produced in huge quantities globally, and the usual practice is to dump them into legal or illegal landfills. Recycled tiles (RT) are being used in soil stabilisation which is considered as sustainable solution to reduce the amount of waste and solve the geotechnical problems. Although the stabilisation of soil using RT improved the soil properties, it could not achieve the standard values required for construction. Thus, this study uses 20% RT together with low cement content (2%) to stabilise soft soil. Series of consolidated undrained triaxial compression tests were conducted on untreated and RT-cement treated samples. Each test was performed at 7, 14, and 28 days curing period and 50, 100, and 200 kPa confining pressures. The results revealed an improvement in the undrained shear strength parameters (cohesion and internal frication angle) of treated specimens compared to the untreated ones. The cohesion and friction angle of the treated samples were increased with the increase in curing time and confining pressure. The peak deviator stress of treated samples increases with the increment of either the effective confining pressures or the curing period. Microstructural and chemical tests were performed on both untreated and RT-cement treated samples, which included field emission scanning electron microscopic (FESEM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and energy dispersive X-ray spectrometer (EDX). The results indicated the formation of cementation compounds such as calcium aluminium hydrate (C-A-H) within the treated samples. Consequently, the newly formed compounds were responsible for the improvement observed in the results of the triaxial tests. This research promotes the utilisation of RT to reduce the amount of cement used in soil stabilisation for cleaner planet and sustainable environment.

• Clean Technology
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• v.22 no.2
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• pp.132-138
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• 2016

The emission of SO₂ is inevitable in case of combustion of most fossil fuels except LNG in commercial power plant which has a bad effect on the durability of SCR catalyst. To develop a low temperature SCR catalyst which has a high NOx removal performance and excellent durability to SO₂, V₂O₅/TiO₂ catalysts were prepared by coating on the metal foam substrate with the impregnation amount of Sb₂O₃ as promotor. This study has evaluated the NOx removal performance and the durability to SO₂ on a laboratory scale atmospheric reactor and analyzed the properties of the prepared catalysts by means of porosimeter, BET, SEM (scanning electron microscope), EDX (energy dispersive x-ray spectrometer), XPS (X-ray photoelectron spectroscopy). It was found that the surface area of catalyst increased with the impregnation amount of Sb₂O₃ and the NOx removal performance showed the highest value at the 2 wt% impregnation of Sb₂O₃. This results was considered to be due to the optimum active site on the catalyst surface. And also, Sb₂O₃ impregnated catalysts presented that NOx removal performance was maintained despite the exposure to SO₂ for 5 hours. Therefore it was confirmed that metal foam SCR catalyst for low temperature could be manufactured with the optimum control of Sb₂O₃ impregnation according to the SO₂ presence or not.

• Asian Journal of Atmospheric Environment
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• v.7 no.4
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• pp.209-216
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• 2013

This study focused on a comprehensive and detailed interpretation for the springtime air quality influenced by both artificial (particulate matter (PM) and asbestos) and biological (pollen) sources in Fukuoka Prefecture, Japan. An intensive measurement of PM was conducted at four characteristic sites (i.e., a heavy traffic area, a residential area, an industrial area, and a desolate area) in the Fukuoka Prefecture during spring of 2007. Analysis of major ionic species in $PM_{2.5}$ was performed by an Ion Chromatography, and asbestos and pollen were identified by Scanning Electron Microscopy with an energy dispersive X-ray spectrometer (EDX). $PM_{2.5}$ concentration ($65.3{\mu}gm^{-3}$) measured in an industrial area (site C) was extraordinarily high compared to those monitored in other areas; it greatly exceeded the Japan's $PM_{2.5}$ criteria (a daily average of $35{\mu}gm^{-3}$). NOAA's HYSPLIT dispersion model suggests that this high level of $PM_{2.5}$ monitored at site C is unlikely to affect the Asian continent. The ambient concentrations of $PM_{2.5}$-related anions ($NH_4{^+}$, $NO_3{^-}$, and $SO_4{^{2-}}$) and their relative contributions to $PM_{2.5}$ were also investigated in four study areas. The concentrations of these major water-soluble ions exhibit not only strong spatial dependence but also different ratios to each other. Asbestos fiber (crocidolite and amosite) concentration values changed in the range of 2.5 to 14.4 f per liter of air. The number of pollen grains showed that Cedar ranked higher in concentration than other types of pollen, with the maximum concentration at site A.

• Nuclear Engineering and Technology
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• v.52 no.6
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• pp.1304-1317
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• 2020

The tubes in a heat exchanger, such as a steam generator (SG), are subjected to crossflow, and interaction between tubes and supports can happen, which can cause fretting wear of tubes. Although many experiments and models have been established, some detailed mechanisms are still not sufficiently clear. In this work, more attention is paid to obtain the regulation of impact and sliding in the complex process and many factors, such as excitation forces and clearances. The responses and contact forces were analyzed to obtain clear understanding of the influences of these factors. Room temperature tests in the air were established. The results show that the effect of clearance on the normal work rate is not monotonous and instead has two peaks. The force ratio can influence the normal work rate by changing the distribution of contact angles, which can result in higher sliding in the contact process. Fretting wear tests are conducted, and the wear surfaces are analyzed by a scanning electron microscope (SEM) and energy dispersive X-ray spectrometer (EDX). The results of this work can serve as a reference for impactsliding contact analysis between AVBs and tubes in steam generators.