• Journal of Adhesion and Interface
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• v.15 no.1
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• pp.1-8
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• 2014

Ion exchange membrane is widely used in various fields such as electro dialysis, diffusion dialysis, redox flow battery, fuel cell. PVC cation exchange membrane using ultrasonic modification was prepared by sulfonation reaction in various sulfonation times. Sulfuric acid was used as a sulfonating agent with ultrasonic condition. We've characterized basic structure of sulfonated PVC cation exchange membrane by FT-IR, EDX, water uptake, ion exchange capacity (IEC), electrical resistance (ER), conductivity, ion transport number and surface morphology (SEM). The presence of sulfonic groups in the sulfonated PVC cation exchange membrane was confirmed by FT-IR. The maximum values of water uptake, IEC, electrical resistance and ion transport number were 40.2%, 0.87 meq/g, $35.2{\Omega}{\cdot}cm^2$ and 0.88, respectively.

• Journal of the Korean Applied Science and Technology
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• v.36 no.1
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• pp.153-164
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• 2019

To develop a high performance SCR catalyst which has better specific surface area, lightness of weight and fast temperature response than those of existing commercial SCR catalyst, metal foam type SCR catalysts were prepared by washcoating with vanadium, tungsten and binder. The de-NOx performance test of the prepared catalysts was carried out on atmospheric micro-test unit at lab. scale according to space velocity variation and temperature change, and the characteristics of them were analyzed by Porosimeter, SEM(scanning electron microscope), EDX(energy dispersive x-ray spectrometer), ICP(inductively coupled plasma) and Stereomicroscope. The NOx reduction performance decreased as the space velocity increased and was found to be the best at 3.5 wt.% contents of the vanadium and tungsten. It was found that the larger amount of binder was added, the worse the NOx reduction performance was, which was considered to be that the number of active sites of the prepared catalyst surface was occupied by the binder. We found that the amount of binder to be added to prepare the catalyst should be properly controlled by the condition of coated catalyt surface.

• Membrane Journal
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• v.28 no.6
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• pp.414-423
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• 2018

In this study, the commercial nanofiltration membranes were modified with octyltrimethoxysilane(OcTMS) and (3-aminopropyl)trimethoxysilane (APTMS) to improve fouling resistance and to separate dye. The chemical structure and binding energy of elements of silane-deposited surface were analyzed using XPS analysis. And the morphology and hydrophilicity property of silane-modified NF membrane were analyzed using FE-SEM, EDX, AFM, and contact angle. The surface charge of silane-modified NF membrane was characterized by zeta potentiometer analyzer. As a result, silane-modified NF membrane improved fouling resistance about 2 times as compared with that of the commercial membrane. And the silane-modified NF membranes effectively were removed cation dye over 98%.

• Proceedings of the Korea Association of Crystal Growth Conference
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• 1997.10a
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• pp.69-74
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• 1997

MCFC(Molten Carbonate Fuel Cell) Ni anode의 기계적 특성을 개선시키기 위해서 Ni-W복합재료를 기계적 합금법으로 제조하였다. 기계적 합금화한 분말을 XRD, SEM으로 관찰한 후 두께 1mm, 직경 8mm의 원반형으로 성형하였다. 소결은 120$0^{\circ}C$의 수소 분위기내에서 10시간 행하였다. 이렇게 제조한 시편의 절단된 면을 연마하여 SEM 및 EDX로 관찰하였으며 XRD로써 성분분석 하였다. 기계적 합금화 시간이 증가함에 따라 불충격에 의한 결정립 미세화가 이루어졌으며 80시간 기계적 합금시 재료의 규칙적인 결정이 파괴되어 비결정질화 되었다. 기계적합금으로 Ni 기지내에 균일하게 분포된 W은 분산강화효과를 통해 Ni anode의 기계적 특성을 개선시킬 것으로 기대된다.

• 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.

• Journal of Conservation Science
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• v.16 s.16
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• pp.27-38
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• 2004

This study was performed to characterize historical paper artefacts from 16th to 19th century from Chungbuk National University Museum (CNUM) in Korea. In order to know the fiber composition, surface features and fiber orientation in historic paper artefacts, LM, SEM and EDX analysis observations were applied. Based on tested results, it was concluded that Korean historic papers from 16 to 19th century were made of paper mulberry fibers called dak, which had 2.79-16.03 m of fiber lengthes and $4.5-26{\mu}m$ of lumen widthes, and they were relatively well preserved. According to EDX analysis, the examined papers differed to the contents of inorganics. High contents of S, Si, Ca, P and Al refer to use fillers, such as gypsum, clay and talc, for paper artifacts. In particular, half of samples contained some amounts of S, Cl and Fe. Since those inorganics might be potentially harmful for the paper permanency, therefore it should be considered special restoration measures from the preservation point of view.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.17 no.4
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• pp.172-178
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• 2007

Mica (muscovite) powders were synthesized by hydrothermal method (horizontal turning method). The hydrothermal conditions for the synthesis of mica were prepared by the ratio of $K_2O : Al(OH)_3 : SiO_2$ = 1 : 3 : 3 mol% as the starting materials with KOH (8 mol%) solution as the hydrothermal solvent and reaction temperature at $260^{\circ}C$ for 72hrs. The synthetic powder used for preparation of nano silver coated mica by vertical hydrothermal treatment. The hydrothermal conditions for the treated as nano silver coating were prepared by the synthetic powder as raw materials, triple distilled water ($0.5{\ell}$) solution as the hydrothermal solvent with nano silver sol (1,000 ppm) as the material of nano silver coating and reaction temperature at $160{\sim}260^{\circ}C$ for 72 hrs. After hydrothermal treatment, structural, judgment of nano silver coating and character of nano silver coated mica were examined by XRD, SEM, TEM-EDX and shake plask method.

• Journal of Conservation Science
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• v.22
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• pp.99-108
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• 2008

This research aimed to provide a scientific methodology for removing white and black/brown coloured stains on the wall paintings of tombs of Jinpari No 1 and No 4. in the Democratic People's Republic of Korea. For the analysis of chemical composition of stains of the samples from the wall paintings, a microscope and SEM/EDX were used. The analysis confirmed that the fomula of white coloured stains should be $CaSO_4$ or $CaCO_3$ and the black/brown coloured stains should be $CaSO_4$ or $CaCO_3$ with soil deposition. Because of the difficulties of testing several cleaning solutions on sample patches of large area of the painting, the author considered a risk-free cleaning solution as being the most appropriate one, with Ammonium bicarbonate and Anion exchange resin showing satisfactory cleaning effect without visible side effects. For the removal of dense layer of stains, the research suggested that physical cleaning should be followed by applying a cleaning solution.

• Polymer(Korea)
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• v.33 no.5
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• pp.452-457
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• 2009

Hybrid nanomaterials consisting of multi-walled carbon nanotube(MWNT) and/or PEDOT of conductive polymer were prepared in this study. In the presence of catalyst and ligand, the MWNT-Br compound prepared by the successive surface treatment reaction was mixed with MMA to initiate the atom transfer radical polymerization process. PMMA was covalently linked to the surface of MWNT for the formation of MWNT/PMMA nanocomposites. The EDOT and oxidant were added in the aqueous emulsion of PS produced via a miniemulsion polymerization process and then it proceeded to carry out the oxidative chemical polymerization of EDOT for the preparation of PEDOT/PS nanoparticles with the core-shell structure. The aqueous dispersion of PEDOT:poly(styrene sulfonate) (PSS) was mixed with the silica particles treated with a silane compound and thus PEDOT:PSS-clad silica nanoparticles were prepared by the surface chemistry reaction. The hybrid nanomaterials were analyzed by using TEM, FE-SEM, TGA, EDX, UV, and FT-IR.

• Journal of the Korean Vacuum Society
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• v.13 no.3
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• pp.127-131
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• 2004

Package reliability test was conducted to investigate the effect of solder composition on the ball fatigue strength for BGA (Ball Grid Array) packaging. The test pieces are assembled using eutectic composition 63Sn/37Pb, 62Sn/36Pb/2Ag, and 63Sn/34.4Pb/2Ag/0.5Sb solder after pre-conditioning at MRT Lv 3 (Moisture Resistance Test Level) and then conducted under T/C (Temperature Cycle test). For each case, the ball shear strength was obtained and micro structure photos were taken. SEM (scanning electron microscope) and EDX (Energy Dispersive X-ray) were used to the analyze failure mechanism. The growth rate of Au-Sn intermetallic compound in Sn63Pb34.5Ag2Sb0.5 solder was slow when compared to 63Sn/37Pb solder and 62Sn/36Pb/2Ag solder. The degradation of shear strength of solder balls caused by solder composition was discussed.