• 한국재료학회지
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• 제30권12호
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• pp.701-708
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• 2020

Irradiation of the metal nanoparticles causes local plasmon resonance in a specific wavelength band, which can improve the absorption and scattering properties of a structure. Since noble metal nanoparticles have better resonance effects than those of other metals, it is easy to identify plasmonic reactions and this is advantageous to find the optical tendency. Compared to having a particle gap or randomly arranged particle structures, densely and evenly packed structures can exhibit more uniform optical properties. Using the uniform properties, the structure can be applied to optical filtering applications. Therefore, in this paper, validation tests about metal nanoparticles and thin film structures are conducted for more accurate analysis. The optical properties of monolayer and bilayer noble metal nanoparticle structures with different diameters, packed in a uniform array, are investigated and their optical trends are analyzed. In addition, a thin film structure under identical conditions as metal nanoparticle structure is evaluated to confirm the improved optical characteristics.

• 설비공학논문집
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• 제10권3호
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• pp.334-342
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• 1998

In this experimental study, methanol was chosen as a system material for a long -distance heat transportation. Not only transition metals but also noble metals were investigated as an active component, and several metal oxides, such as ${\gamma}$-$Al_2$,$O_3$, $SiO_2$, etc. as a support. In general, transition metal catalysts absorbed more heat than noble metal catalysts. The amount of heat absorption and CO selectivity depends on temperature and methanol partial pressure, and 25$0^{\circ}C$ Ni/$SiO_2$ catalyst showed the best result for methanol decomposition reaction.

• 한국막학회:학술대회논문집
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• 한국막학회 2003년도 The 4th Korea-Italy Workshop
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• pp.25-28
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• 2003

Low cost composite metallic membranes for the hydrogen separation and production have been prepared by using thin Pd-Ag foils reinforced by metallic (stainless steel and nickel) structures. Especially, “supported membranes” have been obtained by a diffusion welding procedure in which Pd-Ag thin foils have been joined with perforated metals (nickel) and expanded metals (stainless steel): in these membranes the thin palladium foil assures both the high hydrogen permeability and the perm-selectivity while the metallic support provides the mechanical strength. A second studied method of producing "laminated membranes" consists of coating non-noble metal sheets with very thin palladium layers by diffusion welding and cold-rolling. Palladium thin coatings over these metals reduce the activation energy of the hydrogen adsorption process and make them permeable to the hydrogen. In this case, the dense non-noble metal has been used as a support structure of the thin Pd-Ag layers coated over its surfaces: a proper thickness of the metal assures the mechanical strength, the absence of defects (cracks, micro-holes) and the complete hydrogen selectivity of the membrane. membrane.

• 한국결정성장학회지
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• 제19권5호
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• pp.251-255
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• 2009

나노사이즈의 귀금속을 $TiO_2$ 매트릭스에 균질하게 분산 시킨 구조는 염료감응형 태양전지의 유망한 광전극 특성을 나타내는 것으로 보고되고 있다. 이와 같은 금 및 백금 나노미립자를 균질하게 분산된 구조의 광전극을 제작하기 위하여 석영 및 ITO 기판위에 동시스퍼터법에 의하여 박막을 합성 하였다. XRD분석을 통하여 상분석을 수행 한 결과 합성된 나노컴포지트는 Rutile상이 지배적인 결정 구조를 나타냈으며 열처리를 $600^{\circ}C$까지 진행함에 따라 $TiO_2$ 결정성의 향상 및 귀금속인 금 및 백금의 나노미립자가 증가 하는 결과를 나타내었다. 귀금속인 금 및 백금이 분산된 $TiO_2$ 광전극에서는 자외선(UV) 영역을 포함하여 가시광(VIS) 영역의 빛의 조사에 광전류 응답 특성을 발현 하였다. 가시광선 영역에서 발현된 광전류 응답 특성은 나노사이즈로 분산된 금 및 백금 금속과 $TiO_2$와의 계면 준위에 기인 한 것으로 판명 되었다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 1995년도 제8회 학술발표회 논문개요집
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• pp.0114-115
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• 1995

• 청정기술
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• 제17권3호
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• pp.225-230
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• 2011

다양한 귀금속 촉매를 이용한 hydrocarbon selective catalytic reduction 반응특성을 조사하였다. 가장 우수한 활성금속은 Pt, 지지체는 활성금속과 지지체간 강한 상호작용에 의하여 $CeO_2$, $TiO_2$였으며, NOx 전환율은 약 55%를 나타내었다. 활성금속으로서 Pd, Rh, Ag 촉매들은 20% 미만의 전환율을 보였으며, 지지체로서 $SiO_2$, $ZrO_2$ 또한 다른 지지체들보다 저조한 활성을 나타내었다. 조업조건에 따른 촉매의 성능을 조사하기 위하여 환원제의 종류, 양, 산소농도, 공간속도에 따른 실험을 수행하였다. 환원제로서 메탄이 프로판보다 우수함을 확인하였고, 메탄/질소 산화물 비가 증가할수록 성능이 우수하였으며, 산소농도가 증가할수록, 그리고 공간속도가 감소할수록 촉매의 성능은 증가함을 확인할 수 있었다.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2010년도 추계학술대회 초록집
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• pp.90.2-90.2
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• 2010

The coated metallic bipolar plates are getting attractive due to their good feasibility of mass production, low contact resistance, high electrical/thermal conductivity, low gas permeability and good mechanical strength comparing with graphite materials. Yet, metallic bipolar plates for polymer electrolyte membrane(PEM) fuel cells typically require coatings for corrosion protection. Other requirements for the corrosion protective coatings include low electrical contact resistance between metallic bipolar plate and gas diffusion layer, good mechanical robustness, low mechanical and fabrication cost. The authors have evaluated a number of protective coatings deposited on stainless steel substrate by electroplating. The coated metallic bipolar plates are investigated with an electrochemical polarization tests, salt dipping tests, adhesion tests for corrosion resistance and then the contact resistance was measured. The results showed that the selective samples electroplated with optimized method, satisfied the DOE target for corrosion resistance and contact resistance, and also were very stabilized in the typical fuel cell environments in the long-term.

• 한국해양공학회지
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• 제1권2호
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• pp.93-100
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• 1987

Corrosion fatigue cracking of the austenitic stainless steel(bese metal & heat affected zone by TIG weld) was studied experimentally under the environments of various specific resistance and air. The characteristics of corrosion fatigue crack growth rate and the environmental constants of paris' rule were investigated for SUS 304 weldments in the various specific resistance. The influences of stress intensity factor range and corrosion on the crack growth rate were compared. The characteristics of corrosion fatigue cracking for the weldments were inspected from mechanical, electrochemical and microstructural point of view. Main results obtained are as follows: 1) As the specific resistance decreases, the environmental constant C of paris'rule increases(hence the corrosion fatigue crack growth rate is rapid), but the environmental constant m decreases, so the effect of corrosion to the crack growth rate is more susceptible than thet of stress intensity factor range. 2) As the stress intensity factor range decreases, the corrosion fatigue crack growth rate of heat affected zone is more susceptible than that of the base metal. 3) The corrosion fatigue crack growth rate of the heat affected zone is more rapid than that of the base metal, because of the phenomenon of softening and the less noble potential coused by wedlding heat cycle. 4) The corrosion fatigue cracking of SUS 304 weldment appears transgranular fracture.

• 센서학회지
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• 제29권6호
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• pp.382-387
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• 2020

Hydrogen (H₂) is considered as a new clean energy resource for replacing petroleum because it produces only H₂O after the combustion process. However, owing to its explosive nature, it is extremely important to detect H₂ gas in the ambient atmosphere. This has triggered the development of H₂ gas sensors. 2-dimensional (2D) graphene has emerged as one of the most promising candidates for chemical sensors in various industries. In particular, graphene exhibits outstanding potential in chemoresistive gas sensors for the detection of diverse harmful gases and the control of indoor air quality. Graphene-based chemoresistive gas sensors have attracted tremendous attention owing to their promising properties such as room temperature operation, effective gas adsorption, and high flexibility and transparency. Pristine graphene exhibits good sensitivity to NO₂ gas at room temperature and relatively low sensitivity to H₂ gas. Thus, research to control the selectivity of graphene gas sensors and improve the sensitivity to H₂ gas has been performed. Noble metal decoration and metal oxide decoration on the surface of graphene are the most favored approaches for effectively controlling the selectivity of graphene gas sensors. Herein, we introduce several strategies that enhance the sensitivity of graphene gas sensors to H₂ gas.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2012년도 추계총회 및 학술대회 논문집
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• pp.90-90
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• 2012

Catechol moiety has enough reducing capability of reducing metal ions. Catechol-grafted polymer is chemically synthesized and electrospun into nanofibers as templates for metal nanostructures. The metal nanostructures are spontaneously generated on the catechol-grafted polymer nanofibers under ambient conditions.