• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2005년도 추계학술대회 논문집 Vol.18
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• pp.122-123
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• 2005

단층벽 탄소나노튜브(Single-walled carbon nanotube)를 성장시키고 성장된 탄소나노튜브를 여러 단계의 여과과정이 필요 없는 단순한 정제과정을 통하여 비정질 탄소 찌꺼기, 촉매 금속 등의 불순물을 제거하였다. 성장 온도가 증가함에 따라 수율이 증가하고 불순물의 함유량이 적은 탄소나노튜브가 성장이 되었으며 전반적으로 0.41-2.0 nm의 균일한 직경을 가진 SWNT가 합성이 되었으며 정제 후 96% 이상의 순도를 가진 SWNT를 얻을 수 있었다. 전반적으로 실험결과에 대한 물질의 특성 은 field emission scanning electron microscopy (FESEM)와 X-ray diffraction (XRD) 그리고 Raman spectroscopy로 조사하였다.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2009년도 춘계학술대회 논문집
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• pp.369-372
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• 2009

In the present study, the effect of chemical treatment on graphite nanofibers (GNFs) supports with various concentrated nitric acids was investigated for methanol oxidation. To optimize the electrocatalytic activity, PtRu catalysts were deposited on GNF supports by impregnation method. The surface and structural properties of the GNF supports were characterized by X-ray photoelectron spectroscopy (XPS), element analyzer (EA), and X-ray diffraction (XRD). The morphology of the catalysts was observed by means of transmission electron microscopy (TEM). The electrocatalytic activity of PtRu/GNF catalysts was investigated by cyclic voltammetry measurement. As a result, the oxygen functional groups were introduced on the GNF supports and were gradually increased with increasing of concentrated nitric acid, causing the smaller particle size and higher loading level. And the electrocatalytic activity of the catalysts for methanol oxidation was gradually improved. Consequently, it was found that chemical treatments could influence on surface properties of the carbon supports, resulting in enhancing the electrocatalytic activity of the catalysts for DMFCs.

• Corrosion Science and Technology
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• 제21권4호
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• pp.250-257
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• 2022

Transition metal sulfide materials have emerged as a new anode material for Li secondary batteries owing to their high capacity and rate capability facilitated by fast Li-ion transport through the layered structure. Among these materials, niobium disulfide (NbS₂) has attracted much attention with its high electrical conductivity and high theoretical capacity (683 mAh g^-1). In this study, we propose a facile synthesis of Fe_xNbS₂/C composite via simple ball milling and heat treatment. The starting materials of FeS and Nb were reacted in the first milling step and transformed into an Fe-Nb-S composite. In the second milling step, activated carbon was incorporated and the sulfide was crystallized into Fe_xNbS₂ by heat treatment. The prepared materials were characterized by X-ray diffraction, electron spectroscopies, and X-ray photoelectron spectroscopy. The electrochemical test results reveal that the synthesized Fe_xNbS₂/C composite electrode demonstrates a high reversible capacity of more than 600 mAh g^-1, stable cycling stability, and excellent rate performance for Li-ion battery anodes.

• 한국물환경학회지
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• 제20권3호
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• pp.241-244
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• 2004

Radiation treatment with gamma-rays and electron-beams was used to remove polyvinyl alcohol(PVA), one of the main components of dyeing wastewater. PVA was effectively decomposed by radiation treatment, thus the removal was near 100 % at an initial PVA concentration of 44 mg/L. However, total organic carbon(TOC) removal was less than 5 % due to lower transformation of PVA to $CO_2$. This directly indicates the radiation treatment alone is not appropriate for the complete decomposition of PVA. In this sense, the improvement of biodegradability($BOD_5/COD$) of PVA by radiation treatment was studied. Both gamma-ray and electron-beam treatments significantly increased the biodegradability of PVA by transforming non-biodegradable PVA to biodegradable by-products. This suggests radiation treatment, especially electron-beam treatment that showed better improvement of biodegradability, can be used as a pre-treatment of biological degradation process of PVA.

• 대한금속재료학회지
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• 제50권7호
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• pp.545-548
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• 2012

The optical and electronic properties of Indium Tin Oxide (ITO) thin films deposited on a RF-plasma treated glass substrate were investigated by X-Ray Photoelectron Spectroscopy (XPS), Ultra-violet Photoelectron Spectroscopy (UPS), Reflected Electron Energy Loss Spectroscopy (REELS). The modification of glass substrates was carried out by varying the time of the plasma surface treatment in an oxygen atmosphere. The focus of this research was to examine how the optical and electronic properties of ITO thin films change with the plasma treatment time. The surface energy increased since the carbon bonds were removed from the surface after the glass substrate received the surface treatment. The ITO thin films produced on the glass substrate with surface treatment showed that the high optical transmittance was approximately 85%. The measured band gap energy was as high as 3.23 eV when the plasma treatment time was 60 s and the work function after the treatment was increased by 0.5 eV in comparison to that before the treatment of 60 s. The ITO thin film exhibited an excellent sheet resistance of $2.79{\Omega}/{\Box}$. We found that the optical and electronic properties of ITO thin films can be improved by RF-plasma surface treatment.

• Carbon letters
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• 제12권3호
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• pp.143-151
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• 2011

Bagasse fly ash (BFA) is one of the important wastes generated in the sugar industry; it has been studied as a prospective low-cost adsorbent in the removal of congo red (CR) from aqueous solutions. Chemical treatment with $H_2O_2$ was applied in order to modify the adsorbability of the raw BFA. Batch studies were performed to evaluate the influence of various experimental parameters such as dye solution pH, contact time, adsorbent dose, and temperature. Both the adsorbents were characterized by Fourier-transform infrared spectrometer, energy-dispersive X-ray spectrophotometer and nitrogen adsorption at 77 K. Equilibrium isotherms for the adsorption of CR were analyzed by Langmuir, Freundlich and Temkin models using non-linear regression technique. Intraparticle diffusion seems to control the CR removal process. The obtained experimental data can be well described by Langmuir and also followed second order kinetic models. The calculated thermodynamic parameters indicate the feasibility of the adsorption process for the studied adsorbents. The results indicate that BFA can be efficiently used for the treatment of waste water containing dyes.

• 자원리싸이클링
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• 제10권3호
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• pp.29-36
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• 2001

전기화학적 환원 반응을 이용하는 전기 분해에 의한 방법으로 중금속 폐수를 처리하여 금속성분을 회수하는데 있어 cyclic voltammetry를 적용하였다. 아연용액에서의 아연전극과 탄소전극에 대한 전기적 반응 특성은 voltammogram으로 확인할 수 있었으며 수중 아연이온 환원은 전위가 -0.76V 이하에서 반응이 일어나는 것을 알 수 있었다. 용액 중 아연이온의 산화와 환원으로 인해 형성되는 금속 특성은 X선 회절분석 결과를 통해서 확인할 수 있었으며, AFM 이용하여 구리판에 환원된 아연을 관찰할 수 있었다. 본 연구의 결과는 전기분해에 의한 폐수 중 중금속의 처리 및 회수에 있어 기초자료로 활용죌 수 있을 것으로 사료된다.

• 공업화학
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• 제27권6호
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• pp.627-632
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• 2016

PVDF-PVC 적층필름의 계면접착력을 향상시키기 위한 새로운 방법으로 PVDF 필름 표면에 유전체장벽 코로나 방전을 통한 EMA 단량체 커플링을 시도하였다. EMA 1% 분위기에서 코로나 표면처리한 PVDF 필름을 사용하여 제조한 PVDF-PVC 적층필름의 계면접착력은 코로나 처리하지 않은 PVDF에 비해 현저히 향상되었다. 코로나 방전처리에 의해 PVDF 필름 표면의 접촉각은 현저히 감소하였다. XPS 분석 결과, 코로나 처리에 의해 필름 표면의 탄소와 산소함량은 증가하는 반면 불소 함량은 감소하였다. XPS $C_{1s}$ 피크의 curve fitting 결과, 코로나 방전 처리에 의해 비극성 C-C 결합 탄소와 산소와 결합하는 탄소의 비율은 점차 증가한 반면, 불소와 결합하는 탄소의 비율은 크게 감소하는 경향을 나타내었다.

• 폴리머
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• 제33권3호
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• pp.263-267
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• 2009

d-PMMA(deuterated poly(methyl methacrylate)) 박막 표면의 친수성을 향상시키기 위해 산소 플라즈마에 노출시켰다. 이 때 모든 조건은 동일하며, 플라즈마에 대한 노출 시간만을 0초에서 180초까지 변화를 주어 노출 시간에 대한 영향을 접촉각과 X-ray 반사율 장치, 중성자 반사율 장치, XPS(X-ray photoelectron spectroscopy)를 이용해 조사하였다. 노출 시간이 증가할수록 물 접촉각은 작아지며, 산소의 조성은 커짐을 확인함으로써 산소의 조성이 친수성 향상에 큰 영향을 미치는 것을 확인할 수 있었다. 또한, X-ray 반사율 장치를 이용해 얻은 에칭률을 통해서 d-PMMA 박막에 대한 산소 플라즈마의 노출 시간에 따른 물리적 특성을 연구하였으며, X-ray 반사율과 중성자 반사율, 그리고 XPS 측정 결과로부터 산소와 탄소의 조성뿐만 아니라 수소의 조성까지도 얻음으로써 플라즈마 처리된 박막의 화학적 성질을 보다 자세히 연구할 수 있었다.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2007년도 추계학술대회 논문집
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• pp.143-146
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• 2007

Birnessite-type manganese dioxide($MnO_2$) was coated uniformly onto carbon nanotubes (CNTs) through a spontaneous direct redox reaction between CNTs and permanganate ions($MnO_4\;^-$). The initial specific capacitance of the $MnO_2/CNT$ nanocomposite in an organic electrolyte at a large current density of 1 A/g was 250 F/g, which is equivalent to 139 mAh/g based on the total weight of the electrode material including the electroactive material, conducting agent and binder. The specific capacitance of the $MnO_2$ in the $MnO_2/CNT$ nanocomposite was as high as 580 F/g (320 mAh/g), indicating excellent electrochemical utilization of the $MnO_2$. The addition of CNTs as a conducting agent can improve the high rate capability of $MnO_2/CNT$ nanocomposite considerably. An analysis of the in-situ X-ray absorption near-edge structure (XANES) showed an improvement in the structural and electrochemical reversibility of the $MnO_2/CNT$ nanocomposite by heat-treatment.