• Bulletin of the Korean Chemical Society
• /
• 제31권11호
• /
• pp.3123-3127
• /
• 2010

A highly sensitive electrochemical detection method for dopamine (DA) has been developed by relying on a multiwalled carbon nanotube (CNT)-sol-gel titania-Nafion composite film modified glassy carbon (GC) electrode. The CNT-titania-Nafion/GC electrode exhibited excellent electrocatalytic activity towards DA. Therefore, the CNT-titania-Nafion/GC electrode showed improved voltammetric and amperometric responses for DA compared to those obtained with both titania-Nafion/GC and Nafion/GC electrodes. The CNT-titania-Nafion/GC electrode gave a linear response ($R^2$ = 0.999) for DA from $0.5\;{\mu}M$ to 0.5 mM with a detection limit (S/N = 3) of $0.1\;{\mu}M$ and a good sensitivity of 150 mA/M while other electrodes such as CNT-Nafion/GC, titania-Nafion/GC, and a bare GC gave a sensitivity of 89, 39, and 36 mA/M, respectively. Besides, the CNT-titania-Nafion/GC electrode displayed very fast response time within 2 s. The modified electrode showed good selectivity against ascorbic acid. The modified electrode showed good stability and reproducibility. The CNT-titania-Nafion/GC electrode was applied to the determination of DA in urine and serum samples.

• 한국전산구조공학회:학술대회논문집
• /
• 한국전산구조공학회 2007년도 정기 학술대회 논문집
• /
• pp.421-426
• /
• 2007

A parametric study to investigate the effects of composition variables on the glass transition and mechanical properties of CNT-based nanocomposites was performed using molecular dynamics simulations. In this study, matrix chain length and CNT length were chosen as the candidate characteristic parameters. In order to understand the effect of both parameters in detail, three sample sets having different chain lengths with the same CNT configuration and two sample sets having different CNT lengths with same chain length were prepared. Other parameters such as volume fraction and density were fixed to enable rigorous comparisons. Amorphous polyethylene is used as matrix polymer and (10,0) zigzag CNT is embedded into the matrix to reinforce polymer matrix. As a result, longer polymer chain length of matrix solely increased glass transition temperature but no reinforcing enhancement was observed. CNT length showed similar increase with little enhancement of elastic modulus. In addition to this, nanocomposites showed temperature-dependent elastic modulus jump passing thorough the glass transition region agrees well with experimental results.

• 한국결정성장학회지
• /
• 제20권1호
• /
• pp.35-42
• /
• 2010

In this paper, three types of CNT/$TiO_2$ composite electrodes were prepared with different methods. The changes in XRD patterns showed that the Electrode A contained a mixed phase of anatase and rutile while the Electrode B and Electrode C contained a typical single and clear anatase crystal structure. From SEM micrographs, $TiO_2$ particles were adhered on the surface of the CNT network in the forms of small clusters. The results of chemical elemental analysis indicated that the main elements such as C, O and Ti were existed. The results demonstrated that the efficiency of photoelectrocatalytic (PEC) oxidation for methylene blue (MB) was higher than that of photocatalytic (PC) oxidation. There was a clear enhancement trend of the MB degradation using the prepared CNT/$TiO_2$ composite electrodes with an increase of applied potential. Finally, the prominent PEC activities of the CNT/$TiO_2$ composites could be attributed to combination effects of photo-degradation of $TiO_2$, electron assistant of CNT and function of applied potential.

• 한국재료학회지
• /
• 제18권1호
• /
• pp.12-17
• /
• 2008

Carbon nanotube (CNT) cathodes were fabricated using nano-sized silver (Ag) powders as a bonding material between the CNTs and cathode electrodes. The effects of the powder size on the sintering behavior, the current density and emission image for CNT cathodes were investigated. As the diameter of the Ag powders decreases to 10 nm, the sintering temperature of the CNT cathode was lowered primarily due to the higher specific surface area of the Ag powders. In this study, it was demonstrated that nano-sized Ag powders can be feasibly used as a bonding material for a screen-printed CNT cathode, yielding a high current density and a uniform emission image.

• 한국정밀공학회지
• /
• 제25권5호
• /
• pp.140-147
• /
• 2008

In this study, a carbon nanotube probe (CNT probe) is proposed as a mechanical force transducer for the measurement of pico-Newton (pN) order force in biological applications. In order to measure nantube's displacement in the air or liquid environment, the fabrication of a CNT probe with tip-specific loading of fluorescent dyes is performed using tip- specific functionalization of the nanotube and chemical bonding between dyes and nanotube. Also, we experimentally investigated the mechanical properties of the CNT probe using electrostatic actuation and fluorescence microscope measurement. Using fluorescence measurement of the tip deflection according to the applied voltage, we optimized the bending stiffness of the CNT probe, therefore determined the spring constant of the CNT probe. The results show that the spring constant of CNT probes is as small as 1 pN/nm and CNT probes can be used to measure pN order force.

• 한국표면공학회지
• /
• 제46권5호
• /
• pp.223-228
• /
• 2013

In this work, the grow of carbon nanotube (CNT) on carbon fiber was introduced on PAN-based carbon fibers for the enhancement of mechanical interfacial strength of carbon fibers-reinforced composites. The surface properties of carbon fibers were determined by scanning electron microscopy (SEM) and mechanical interfacial properties of the composites were studied by interlaminar shear strength (ILSS). From the results, it was found that the mechanical interfacial properties of CNT-carbon fibers-reinforced composites (CNT-CFRPs) enhanced with decreasing the CNT content. The excessive CNT content can lead the failure due to the interfacial separation between fibers and matrices in this system. In conclusion, the optimum CNT content on carbon fiber surfaces can be a key factor to determine the mechanical interfacial properties of the CNT-CFRPs.

• 산업기술연구
• /
• 제39권1호
• /
• pp.7-14
• /
• 2019

Carbon nanotubes (CNT) on metal substrates are definitely beneficial because they can maintain robust mechanical stability and high conductivity between CNT and metal interfaces. Here, we report direct growth of CNT on Ni-based superalloy, Inconel 600, using thermal chemical vapor deposition (CVD) with acetylene feedstock in the growth temperature range of $400-725^{\circ}C$. Furthermore, we studied the effect of substrate pretreatment on the growth yield enhancement and growth temperature decrease of CNT on Inconel 600. Activation energy (AE) for CNT growth was estimated from the CNT height change with respect to the growth temperature. The AE values significantly decreased from 205.03 to 24.35 kJ/mol by the pretreatment of thermal oxidation of Inconel substrate at $725^{\circ}C$ under ambient. Higher oxidation temperature tends to have lower activation energy. The results have shown the importance of pretreatment temperature on CNT growth yield and growth temperature decrease.

• 한국광학회지
• /
• 제22권3호
• /
• pp.117-121
• /
• 2011

본 논문에서는 도파모드공진을 이용한 포화흡수체 반사기를 제안하였다. 포화흡수체로는 탄소나노튜브(CNT)를 사용하였다. 제안된 반사기는 CNT의 두께 변화 없이 modulation depth를 키울 수 있다는 장점이 있다. 제안하는 반사기의 fill factor(F)와 CNT의 두께변화에 따른 modulation depth, 대역폭, 포화되었을 때의 최대 반사율의 특징을 알아보았다. 제안된 반사기는 포화에너지를 줄일 수 있다는 장점이 있고, 100~200nm 얇은 CNT박막에서 50배정도 줄어드는 것을 확인 하였다.

• 한국전기전자재료학회논문지
• /
• 제32권5호
• /
• pp.403-406
• /
• 2019

We prepared yarned carbon nanotube (CNT) fibers from a CNT forest synthesized on a Si wafer by chemical vapor deposition (CVD). The yarned CNT fibers were thermally annealed to reduce their resistance by removing the amorphous carbonaceous impurities present in the fibers. The resistance of the yarned CNT fiber gradually decreased with an increase in the annealing temperature from $200^{\circ}C$ to $400^{\circ}C$ but increased again above $450^{\circ}C$. We carried out thermogravimetric analysis (TGA) to confirm the burning properties of the amorphous carbonaceous impurities and the crystalline CNTs present in the fibers. The pattern of the mass change of the sample CNT fibers was very similar to that of the resistance change. We conclude that CNT fibers should be thermally annealed at temperatures below $400^{\circ}C$ for reducing and stabilizing their resistance.

• 한국정보통신학회:학술대회논문집
• /
• 한국정보통신학회 2022년도 춘계학술대회
• /
• pp.456-458
• /
• 2022

국제해사기구의 환경규제로 조선소에서는 선박의 효율향상을 위한 다양한 연구를 추진하고 있으며, 선박의 무게절감을 위한 노력이 진행 중이다. 최근, CNT소재를 포함하는 복합소재는 일반 철판 소재 대비 40% 이상 무게절감이 가능한 장점이 있어, 선박의 클램프나 도어스킨으로 대체사용이 가능한 장점이 있다. 이에, 본 연구에서는 CNT소재를 포함하는 복합소재의 수명예측을 위해, 가속열화시험 방법과 머신러닝 기법을 이용한 수명예측을 통해 결과를 비교하였다. 가속열화시험은 아레니우스 모델식을 이용하였고, 머신러닝 기법은 회기분석 알고리즘을 이용하여 수명을 예측하였다.