• Journal of Periodontal and Implant Science
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• v.35 no.4
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• pp.863-875
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• 2005

Bovine bone-derived bone substitutes are widely used for treatment of bone defects in dental and orthopedic regenerative surgery. The purpose of this study was to evaluate the basic characteristics of deproteinized bovine bone mineral as a bone graft substitute. Commercially available products from three different bovine bone minerals-Bio-Oss(GeistlichPharma, Switzerland), BBP(Oscotec. Korea), Osteograf/N-300(Dentsply Friadent Ceramed, USA) - were investigated. They were evaluated by scanning electron microscopy(SEM), energy dispersive X-ray spectrometer(EDS), surface area analysis(BET), and Kjeldahl protein analysis. Cell viability on different products was evaluated by 3-(4, 5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide(MTT) assay. The results of this study indicated that each bone substitute displayed distinct surface properties. Furthermore, Kjeldahl protein analysis indicated that residual crude proteins are present in deproteinized bovine bone mineral. BBP showed relatively large amount of residual protein, which indicated that the possibility of disease transmission can not be safely ruled out. Based on the results of this study, it is suggested that active quality management is strongly needed in operations that involve processing bovine bone tissue for medical use.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.16 no.8
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• pp.744-751
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• 2003

Co-Pd alloy thin films prepared by a DC-sputter that have self-organized nano structure(SONS), are promising for high-density information storage media in information era. We prepared the samples by varying Pd contents of 0~8.1 wt% at the substrate temperatures of room temperature (RT) and 200 $^{\circ}C$, respectively Microstructure and Pd contents of the Co$_{1-x}$ Pd$_{x}$ films are probed by a scanning electron microscope (SEM), a transmission electron microscope (TEM) and an energy dispersive spectrometer (EDS). We also investigated the saturation magnetization (Ms), remanence and coercivity of the Co$_{1-x}$ Pd$_{x}$ films. Surface roughness are measured by an atomic force microscope (AFM). We revealed that self-organized nano size Co-enriched phase and Pd-enriched phase existed with Pd contents at the substrate temperatures of RT and 20$0^{\circ}C$ through microstructure characterization. SONS helped to keep the saturation magnetization and enhance the perpendicular anisotropy with Pd contents. Out result implies that we may tune the perpendicular magnetic properties with keeping the saturation magnetization by varying substrate temperatures and Pd contents for high density magnetic recording.rding.

• KCI Concrete Journal
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• v.11 no.3
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• pp.127-140
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• 1999

In this paper, a microscopic analysis of prefinitelv strained cement paste specimen was carried out. The microscopic behavior of concrete under triaxial stress must be fully understood in order to explain the additional ductilitv that comes from lateral confinement and to get microstructural information in large deformed and large strained concrete. The so-called "tube-squash" test was applied to achieve enormously high shear and deviatoric strain of concrete under extremly high pressure without fracture. Then, microscopic analyses by focusing on hydration and microstructure of Prefinitely strained cement paste were carried out on cored-out deformed and virgin (undeformed) cement paste specimens : the first specimen being 40 days old, the second one being one year old. The microscopic analysis bv Field Emission Scanning Electronic Microscope (FESEM) was carried out for comparison between the specimens after 40 days and those arter one year. For one year old specimens, X-Ray Diffractometer (XRD) analysis, Energy Dispersive x-rav Spectrometer (EDS) analysis, and Differential Thermal Analysis/Thermo-Gravitv (DTA/TG) analysis were also carried out to study the hydration and the microstructures of prefinitely strained cement paste specimen by focusing on the methodologies of their microscopic analyses. analyses.

• Journal of the Korean institute of surface engineering
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• v.49 no.2
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• pp.135-140
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• 2016

In this study, we prepared magnesium ion containing oxide films formed on the Ti-6Al-4V using plasma electrolytic oxidation (PEO) treatment. Ti-6Al-4V surface was treated using PEO in Mg containing electrolytes at 270V for 5 min. The phase, composition and morphology of the Mg ion containing oxide films were evaluated with X-ray diffraction (XRD), Attenuated total reflectance Fourier transform infrared (ATR-FTIR) and filed-emission scanning electron microscopy (FE-SEM) with energy dispersive X-ray spectrometer (EDS). The biocompatibility of Mg ion containing oxide films was evaluated by immersing in simulated body fluid (SBF). According to surface properties of PEO films, the optimum condition was formed when the applied was 270 V. The PEO films formed in the condition contained the properties of porosity, anatase phase, and near 1.7 Ca(Mg)/P ratio in the oxide film. Our experimental results demonstrate that Mg ion containing oxide promotes bone like apatite nucleation and growth from SBF. The phase and morphologies of bone like apatite were influenced by the Mg ion concentration.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.08a
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• pp.195.1-195.1
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• 2013

Cu는 금속 박막재료로서 높은 전기전도성을 지니고 있을 뿐만 아니라 Ag, Al, Pt 등 보다 비용이 저렴하여, 높은 전기전도성을 필요로 하는 박막 재료로써 폭넓게 사용되고 있다. 그러나, 낮은 기계적 특성을 지니고 있어서 interconnect와 같은 작은 단면적의 배선재료로 사용될 경우, 높은 전류밀도에 따른 electromigration 현상에 의하여 hillock 또는 void의 형성 등 박막재료의 변형이 생기게 되어서 전자소자의 수명이 단축된다는 단점이 있다. TiN은 금속재료 못지않은 높은 전기 전도성을 지니고 있을 뿐만 아니라, 금속재료에 비하여 높은 기계적 특성과 녹는점을 지니고 있어 다양한 분야로 사용되고 있다. 본 연구에서는 Cu와 TiN composite 박막을 soda-lime glass위에 증착하여 낮은 비저항 뿐만 아니라 Cu와 비교하여 기계적 특성이 향상된 박막을 제작하고자 하였다. Cu와 TiN composite 박막 증착을 위하여 DC reactive magnetron co-sputtering 장비를 사용하였으며, Cu와 Ti 타겟 power, Ar:N2 유량비(Flow rate)을 변화시켜 Cu와 Ti의 조성비 및 TiN의 결정성을 조절하였고, 이를 통하여 박막의 TiN 조성에 따른 낮은 비저항 값과 순수한 Cu 박막과 비교하여 높은 기계적 특성을 지닌 Cu-TiN 박막을 증착하였다. Cu-TiN composite 박막의 구조 및 조성은 SEM (Scanning Electron Microscope), EDS (Energy Dispersive Spectrometer), XPS (X-ray Photoelectron Spectroscopy)장비를 사용하여 분석하였으며, 전기전도도는 4-point probe를 사용하여 측정하였고, Knoop hardness 측정방법을 사용하여 박막의 기계적 특성을 측정하였다.

• Corrosion Science and Technology
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• v.18 no.1
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• pp.24-32
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• 2019

The effects of zinc coating and heat treatment on the corrosion resistance of aluminum alloys including A1100 and the modified A3003, used as heat exchanger tube were investigated in this study. The grain size of the heat-treated specimen is larger than that of the specimen without heat treatment, but the grain size did not significantly affect the corrosion behavior. The concentration of zinc was noted at 11.3 ~ 31.4 at.% for the as-received Zn-coated samples and reduced to 1.2 ~ 2.4 at.% after the heat treatment, as measured by the scanning electron microscopy (SEM) with an energy dispersive spectrometer (EDS) on the surface. The concentration of oxygen is 22 ~ 46 at.% for the zinc coated specimens while noted at 7.4 ~ 12.8 at.% for the specimens after the removal of the coating. The corrosion behavior depended largely on the concentrations of zinc, aluminum, and oxygen on the specimen surface, but not on the Mo content. The corrosion potential was high and the corrosion rate was low for a specimen with a low zinc content, a high aluminum content, and a high oxygen content.

• Journal of the Korean Society of Propulsion Engineers
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• v.23 no.2
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• pp.46-52
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• 2019

This research was conducted to analyze the effects of temperature on coking characteristics of kerosene. The kerosene was heated to 600 K, 700 K, and 800 K, and the cooled samples were collected. The used copper tubes were replaced according to the temperature conditions. The liquid and copper specimens were analyzed by gas chromatography-mass spectrometry and scanning electron microscopy equipped with an energy dispersive x-ray spectrometer, respectively. The results of the analysis confirmed that a carbon deposit was formed from the coking of fuel on the inner surface of the copper specimen at a relatively high temperature (800 K) of the copper tube.

• Korean Journal of Materials Research
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• v.30 no.12
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• pp.709-714
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• 2020

For zinc-air batteries, there are several limitations associated with zinc anodes. The self-discharge behavior of zinc-air batteries is a critical issue that is induced by corrosion reaction and hydrogen evolution reaction (HER) of zinc anodes. Aluminum and indium are effective additives for controlling the hydrogen evolution reaction as well as the corrosion reaction. To enhance the electrochemical performances of zinc-air batteries, mechanically alloyed Zn-Al and Zn-In materials with different compositions are successfully fabricated at 500rpm and 5h milling time. Investigated materials are characterized by X-ray diffractometer (XRD), field emission scanning electron microscope (FE-SEM), and energy dispersive spectrometer (EDS). Alloys are investigated for the application as novel anodes in zinc-air batteries. Especially, the material with 3 wt% of indium (ZI3) delivers 445.37 mAh/g and 408.52 mAh/g of specific discharge capacity with 1 h and 6 h storage, respectively. Also, it shows 91.72 % capacity retention and has the lowest value of corrosion current density among attempted materials.

• Corrosion Science and Technology
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• v.21 no.6
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• pp.487-494
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• 2022

Anodizing is a typical electrochemical surface treatment method that can improve the corrosion and insulating properties of aluminum alloys. The anodization process can obtain a dense structure. It can be used to artificially grow the thickness of an anodization film. Aluminum 3003 alloy used in this study is the most commonly used alloy for batteries due to its high strength and excellent formability as well as its weldability and corrosion resistance. Aluminum 3003 alloy was anodized at 0 ℃ with 0.3 M oxalic acid at 20 V, 40 V, or 60 V for 1 hour, 6 hours, or 12 hours. As a result of analyzing the composition of each specimen with an Energy Dispersive Spectrometer (EDS), aluminum was converted into an oxide film. The thickness of the formed anodization film increased when the applied voltage and anodization time increased. High corrosion potential values and low corrosion current density values were observed for the thickest oxide layer. The anodization film formed by anodization acted as a protective layer. The electrical resistance increased as the applied voltage and anodization time increased.

• Nuclear Engineering and Technology
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• v.55 no.8
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• pp.2889-2896
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• 2023

The waste acceptance criteria for heavy metals in mixed waste should be developed by reflecting the leaching behaviors that could highly depend on the repository design and environment surrounding the waste. The current standards widely used to evaluate the leaching characteristics of heavy metals would not be appropriate for the silo-type repository since they are developed for landfills, which are more common than a silo-type repository. This research aimed to explore the leaching behaviors of cementitious waste with Pb, Cd, and Sb metallic and oxide powders in an environment simulating a silo-type radioactive waste repository. The Toxicity Characteristic Leaching Procedure (TCLP) and the ANS 16.1 standard were employed with standard and two modified solutions: concrete-saturated deionized and underground water. The compositions and elemental distribution of leachates and specimens were analyzed using an inductively coupled plasma optical emission spectrometer (ICP-OES) and energy-dispersive X-ray spectroscopy combined with scanning electron microscopy (SEM-EDS). Lead and antimony demonstrated high leaching levels in the modified leaching solutions, while cadmium exhibited minimal leaching behavior and remained mainly within the cement matrix. The results emphasize the significance of understanding heavy metals' leaching behavior in the repository's geochemical environment, which could accelerate or mitigate the reaction.