• 한국기계가공학회지
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• 제15권6호
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• pp.95-100
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• 2016

We suggest and simulate an optical filter that a red wavelength range cannot transmit to protect the psychological stress that originates from the cognition of red color in emergency medical technicians. When a nanohole hexagonal array is fabricated on gold film using Anodic Aluminum Oxide (AAO), the blocked wavelength can be tuned by the hole diameter and film thickness. The characteristic of the transmittance for normal incident white light is simulated with Finite Element Method (FEM) in the MATLAB platform. Although the transmittance of the overall wavelength is reduced by 50% by the gold film, the transmittance of the red wavelength range is decreased by over 87%.

• Bulletin of the Korean Chemical Society
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• 제30권12호
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• pp.2979-2983
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• 2009

Nanowires of polytetrakis(o-aminophenyl)porphyrin (PTAPPNW) were fabricated by electrochemical polymerization with the cyclic voltammetric method in anodic aluminum oxide (AAO) membranes. The glassy carbon electrode (GCE) modified by PTAPPNW, single-walled carbon nanotubes (SWNT) and Nafion as a binder was investigated with voltammetric methods in a phosphate buffer saline (PBS) solution at pH 7.4. The PTAPPNW + SWNT + Nafion/GCE exhibited strongly enhanced voltammetric and amperometric sensitivity towards hydrogen peroxide ($H_2O_2$), which shortened the response time and enhanced the sensitivity for $H_2O_2$ determination at an applied potential of 0.0 V by amperometric method. The PTAPPNW + SWNT + Nafion/GCE can be used to monitor $H_2O_2$ at very low concentrations in biological pH as an efficient electrochemical $H_2O_2$ sensor.

• 대한기계학회논문집B
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• 제39권12호
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• pp.921-925
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• 2015

매년마다 신장질환으로 고통 받는 사람들이 증가하는 추세이다. 가장 흔한 치료법 중 하나는 혈액 투석인데, 이 방법은 많은 시간이 걸리고, 비용이 많이 드는 방법이다. 이러한 이유 때문에, 인공신장 연구의 중요성이 대두되고 있다. 혈액에서 크레아티닌을 여과하는 것은 신장의 주요 기능 중 하나이다. 우리는 이 기능에 초점을 맞춘 새로운 2 채널 마이크로 플루이딕 칩을 고안하였다. 두 개의 PDMS 층을 결합하기 위하여, 아크릴을 가공한 하우징 시스템이 개발하였으며, 이 방법은 여과막을 쉽게 바꿀 수 있다는 이점이 있다. 우리는 알루미늄 양극 산화물(AAO)을 여과막으로 사용하였다. 여과된 용액은 자페반응(Jaffe reation)을 이용하여, 크레아티닌 농도별 흡광도 차이를 분석하였다. 크레아티닌의 양에 대한 표준식을 만들어, 측정한 데이터를 보간하여 여과된 용액의 농도를 확인하였다. 실험을 통하여 유량 및 크레아티닌 농도에 따른 여과율을 얻을 수 있었다.

• Tribology and Lubricants
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• 제33권2호
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• pp.59-64
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• 2017

This study investigates friction and wear characteristics of anodized aluminum (Al) alloy 6061 by using a reciprocating tribotester. The diameter and height of the specimen are 30 mm and 10 mm, respectively. The surface roughness of the mirrored-surface is approximately $0.01{\sim}0.02{\mu}m$, and it is used throughout the current study. As a result of anodizing, the depth and diameter of the nanopore are approximately $25{\mu}m$ and 30-40 nm, respectively. The testing conditions are as follows: loads of 1, 3, and 5 N; a frequency of 1 Hz; a stoke of 3 mm; and a duration of 1800 s. We use deionized water with a volume of approximately $25{\mu}l$, as the lubricant. Micro Vickers hardness measurements show that mirrored-surface specimens had lower hardness values than anodized specimens. Further, their coefficients of friction are lower than those of the anodized samples, and the width of their wear track increases with load, as expected. The anodized specimens' coefficients of friction increase with stable frictional behavior and exhibit insignificant load dependence. Further, we observe that the width of the wear track is less than that of the mirrored-surface specimens, and micro cracks are present near it. Moreover, the anodizing process increases the hardness of the samples, improving their wear resistance. These results indicate that nanoporous structures are not effective in lowering friction under the water-lubricated condition.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2009년도 춘계학술발표대회
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• pp.24.2-24.2
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• 2009

Nanostuctures such as nanodot and nanowire have been extensively studied as building blocks for nanoscale devices. However, the direct growth of the nanostuctures at the desired position is one of the most important requirements for realization of the practical devices with high integrity. Self-assembled nanotemplate is one of viable methods to produce highly-ordered nanostructures because it exhibits the highly ordered nanometer-sized pattern without resorting to lithography techniques. And selective epitaxial growth (SEG) can be a proper method for nanostructure fabrication because selective growth on the patterned openings obtained from nanotemplate can be a proper direction to achieve high level of control and reproducibility of nanostructucture fabrication. Especially, SiGe has led to the development of semiconductor devices in which the band structure is varied by the composition and strain distribution, and nanostructures of SiGe has represented new class of devices such nanowire metal-oxide-semiconductor field-effect transistors and photovoltaics. So, in this study, various shaped SiGe nanostructures were selectively grown on Si substrate through ultrahigh vacuum chemical vapor deposition (UHV-CVD) of SiGe on the hexagonally arranged Si openings obtained using nanotemplates. We adopted two types of nanotemplates in this study; anodic aluminum oxide (AAO) and diblock copolymer of PS-b-PMMA. Well ordered and various shaped nanostructure of SiGe, nanodots and nanowire, were fabricated on Si openings by combining SEG of SiGe to self-assembled nanotemplates. Nanostructure fabrication method adopted in this study will open up the easy way to produce the integrated nanoelectronic device arrays using the well ordered nano-building blocks obtained from the combination of SEG and self-assembled nanotemplates.

• Journal of Electrochemical Science and Technology
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• 제3권2호
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• pp.57-62
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• 2012

In this report, we demonstrate that the longitudinal localized surface plasmon resonance mode can be suppressed when the nanorods were in dumbbell shape. The seed nanorods were synthesized by electrochemical deposition of metals into the pores of anodic aluminum oxide templates. The dumbbell-like nanorods were grown from seed Au-Ni-Au nanorods by a rate-controlled seed-mediated growth strategy. The selective deposition of Au atoms onto Au blocks of Au-Ni-Au nanorods produced larger diameter of Au nanorods with bumpy surface resulting in dumbbell-like nanorods. The morphology of nanorods depended on the reduction rate of $AuCl_4^-$, slow rate producing smooth surface of Au nanorods, but high reduction rate producing bumpy surface morphology. Through systematic investigation into the UV-Vis-NIR spectroscopy, we found that the multiple localized surface plasmon resonance (LSPR) modes were available from single-component Au nanorods. And, their LSPR modes of Au NRs with bumpy surface, compared to the smooth seed Au NRs, were red-shifted, which was obviously attributed to the increased electron oscillation pathways. While the longitudinal LSPR modes of smoothly grown Au NRs were blue-shifted except for a dipole transverse LSPR mode, which can be interpreted by decreased aspect ratio. In addition, dumbbell-like nanorods showed an almost disappeared longitudinal LSPR mode. It reflects that the plasmonic properties can be engineered using complex nanorods structure.

• Bulletin of the Korean Chemical Society
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• 제35권7호
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• pp.1973-1978
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• 2014

Here, we present a facile method to synthesize Pt nanoparticles (NPs) and graphene composite materials (Pt/G) via vacuum filtration. Anodic aluminum oxide (AAO) templates were used to separate Pt/G composite and liquid phase. This method can be used to easily tune the mass ratio of Pt NPs and graphene. Pt NPs, graphene, and carbon nanotubes (CNTs) as building blocks were characterized by a variety of techniques such as scanning electron microscopy, UV-Vis spectroscopy, and Raman spectroscopy. We compared the electrocatalytic activities of Pt/G with Pt NP and CNT films (Pt/CNT) by cyclic voltammetry (CV), CO oxidation, and methanol oxidation. Pt/G was much more stable than pure Pt films. Also, Pt/G had better electrochemical activity, CO tolerance and methanol oxidation than Pt/CNT loaded with the same amount of Pt NPs due to the better dispersion of Pt NPs on graphene flakes without aggregation. We further synthesized Au@Pt disk/G and Pt nanorods/G to determine if our synthetic method can be applied to other NP shapes such as nanodisks and nanorods, for further electrocatalysis studies.

• 공업화학
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• 제20권6호
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• pp.586-592
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• 2009

나노 크기의 배향성을 갖는 구조물의 제작은 자연에 존재하는 여러 가지 형상의 모방을 가능하게 한다. 고분자는 가격이 매우 저렴하며 합성과 가공 그리고 그 구조가 잘 알려져 있는 장점을 갖고 있어 필름(film)의 표면에 이러한 나노 구조물을 제작하고 나노 구조의 특성을 발현하는데 손쉽게 활용할 수 있는 재료이다. 나노 구조물을 제작하는 방법 중 양극산화를 통하여 제작한 다공성 알루미나 템플레이트(porous alumina template)는 매우 규칙적으로 정렬되어 있고 제어하는 공정이 비교적 쉽고 경제적이기 때문에 이를 이용한 연구가 매우 활발하게 진행되고 있다. 본 총설에서는 양극산화 알루미나 템플레이트의 제작과 이를 이용한 나노 구조 고분자 필름의 제작을 설명하고 이러한 나노 구조 필름의 응용범위 및 응용에 필요한 특성에 대하여 기술하였다.

• 전기화학회지
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• 제6권3호
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• pp.208-211
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• 2003

본 연구에서는 CoP나노선재의 미세구조 및 크기에 따른 자기적 성질의 변화를 고찰하였다. 우선 나노선재를 제조하기 위하여 기공의 직경이 각각 20nm, 200nm인 알루미나 형틀을 제조하였고, 이 형틀을 이용하여 전기도금 방법으로 CoP나노선재를 제조하였다. 직경이 20nm인 나노선재의 경우 나노선재의 길이방향으로의 각형성 및 보자력이 각각 0.8, 2600 Oe으로서 지금까지 보고된 나노선재들에 비해 우수한 자기적 성질을 나타내었고 전기도금 시 전류밀도의 영향이 거의 없었다. 그러나 직경이 200nm인 나노선재는 나노선재의 길이방향으로 각형성 및 보자력이 각각 0.15, 1200 Oe으로 20nm나노선재보다 현격하게 감소하였으며 나노선재의 자기적 성질이 전류밀도에 따라 많은 영향을 받고 있음을 확인하였다 즉, 상대적으로 낮은 전류밀도에서 제조된 나노선재일 수록 나노선재와 평행한 방향으로 자화용이축이 배향되어 길이방향으로 각형성 및 보자력이 증가하였다.