• 한국재료학회지
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• 제14권3호
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• pp.175-180
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• 2004

SiC nanotubes were synthesized by CNT-confined reaction. Evaporated SiO gas reacted with carbon nanotubes by VS growth mechanism. By confineded reaction, carbon nanotube was changed to SiC nanotube, and synthesized SiC nanotube was filled partly by the gas reaction in the nanotubes. SiC nanotube's mean diameters were not changed than carbon nanotubes because of means ratio of $CO_2$ and SiO gas was maintained evenly during the process. This result was same of data of simulation. By TEM observastion, SiC nanotube was filled by reaction of inner wall of CNT and SiO gas through the VS reactions. Converted SiC nanotube's compositions were revealed Si and C of 1: 1 ratios at all sites of nanotube by EDS.

• 한국전기전자재료학회논문지
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• 제26권2호
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• pp.87-91
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• 2013

Carbon-nanotube field-effect transistors (CNFETs) have drawn wide attention as one of the potential substitutes for metal-oxide-semiconductor field-effect transistors (MOSFETs) in the sub-10-nm era. Output characteristics of coaxially gated CNFETs were simulated using FETToy simulator to reveal the dependence of drain current on the nanotube diameter and gate oxide thickness. Nanotube diameter and gate oxide thickness employed in the simulation were 1.5, 3, and 6 nm. Simulation results show that drain current becomes large as the diameter of nanotube increases or insulator thickness decreases, and nanotube diameter affects the drain current more than the insulator thickness. An equation relating drain saturation current with nanotube diameter and insulator thickness is also proposed.

• 한국염색가공학회지
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• 제22권1호
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• pp.43-50
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• 2010

The thermal treatment for carbon nanotube was applied to remove the water, metal catalyst and other impurities in carbon nanotube. The surface of carbon nanotube was changed into open structure with acid treatment by mixed solution of $HNO_3$ and $H_2SO_4$. The dispersion property of the functionalized and modified carbon nanotube was assessed with naked eyes by dispersing it in DMF. Carbon nanotube mixd polyurethane film was made to estimate the dispersion property by reflectance of the film with UV-Vis spectrometer. Also the internal structure of carbon nanotube was observed with SEM and TEM and thermal pyrolysis property of the carbon nanotube was measured by TGA and DSC. The surface modification of carbon nanotube by thermal and acid treatments improved the dispersion property of carbon nanotube/polyurethane mixed materials.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2003년도 추계학술발표대회 논문집
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• pp.25-28
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• 2003

Carbon nanotubes(CNTs), since their first discovery, have been considered as new promising materials in various fields of applications including field emission displays, memory devices, electrodes, NEMS constituents, hydrogen storages and reinforcements in composites due to their extra-ordinary properties. The carbon nanotube reinforced nanocomposites have attracted attention owing to their outstanding mechanical and electrical properties and are expected to overcome the limit of conventional materials. Various application areas are possible for carbon nanotube reinforced nanocomposites through the functionalization of carbon nanotubes. Carbon nanotube reinforced polymer matrix nanocomposites have been fabricated by liquid phase process including surface functionalization and dispersion of CNTs within organic solvent. In case of carbon nanotube reinforced polymer matrix nanocomposites, the mechanical strength and electrical conducting can be improved by more than an order of magnitude. The carbon nanotube reinforced polymer matrix nanocomposites can be applied to high strength polymers, conductive polymers, optical limiters and EMI materials. In spite of successful development of carbon nanotube reinforced polymer matrix nanocomposites, the researches on carbon nanotube reinforced inorganic matrix nanocomposites show limitations due to a difficulty in homogeneous distribution of carbon nanotubes within inorganic matrix. Therefore, the enhancement of carbon nanotube reinforced inorganic nanocomposites is under investigation to maximize the excellent properties of carbon nanotubes. To overcome the current limitations, novel processes, including intensive milling process, sol-gel process, in-situ process and spark plasma sintering of nanocomposite powders are being investigated. In this presentation, current research status on carbon nanotube reinforced nanocomposites with various matrices are reviewed.

• 한국염색가공학회지
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• 제26권2호
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• pp.71-78
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• 2014

This review paper is a state of the art report of the development of high performance nano-composites with carbon nanotube. We investigate the research and development (R&D) trends of high performance nano-composites with carbon nanotube by analyzing technical trends in research institutes and industry. We report the R&D and technology trends for the properties and applications of fabrication of hybrid composites with aligned carbon nanotubes, multifunctional fiber/carbon nanotube composites. We discuss the specific topics including unidirectional carbon nanotube, carbon nanotube forests, transfer-printing carbon nanotube technology, deposition of carbon nanotube by electrophoresis, vapor grown carbon fiber (VGCF), cup-stacked carbon nanotube, bucky paper and carbon nanotube yarns in this review paper.

• 한국물환경학회지
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• 제32권5호
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• pp.403-409
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• 2016

In this study, a TiO₂ nanotube was grown on a titanium plate by using anodic oxidation method for the evaluation of TiO₂ nanotube morphology. The TiO₂ nanotube was grown in an electrolyte containing ethylene glycol, 0.2 wt% of NH₄F and 2 vol% of H₂O. Applied voltage varied from 30 to 70 V and the morphology of the TiO₂ nanotube was observed. After anodization, a TiO₂ nanotube plate was immersed in 35℃ ethanol for 24 hours. Anatase and rutile crystal forms of TiO₂ nanoutbe were observed after annealing. 4-chrolobenzoic acid, a probe compound for OH radicals, was dissolved in H₂O in order to measure the OH radical. Liquid chromatography was used to check the concentration of the 4-chrolobenzoic acid. The OH radical generation by TiO₂ nanotube plate was proportionate to the length of the TiO₂ nanotube. Furthermore, when the number of TiO₂ nanotube plate increased, the OH radical generation increased as well.

• 한국물환경학회지
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• 제35권6호
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• pp.550-556
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• 2019

This study was carried out to improve the photocatalytic reaction of TiO₂ photocatalyst. During the photocatalytic reaction, OH radicals are generated and they have an excellent oxidation capability for wastewater treatment. To evaluate the OH radicals generated according to crystallographic structure of TiO₂ nanotubes photocatalyst, a probe compound, 4-Chlorobenzoic acid was monitored to evaluate OH radical. Ultraviolet light was applied for photocatalytic reaction of TiO₂. The 4-Chlorobenzoic acid solution was prepared at laboratory. TiO₂ nanotube was grown on titanium plate by using anodization method. The annealing temperature for TiO₂ nanotube was varied from 400 to 900 ℃ and the crystal forms of the TiO₂ nanotube was analyzed. Depending on annealing temperature, TiO₂ nanotubes have shown different crystal forms; 100% anatase (0 % rutile), 18.4 % rutile (81.6 % anatase), 36.6 % rutile (63.4 % anatase) and 98.6% rutile (1.4% anatase). As the annealing temperature increases, the rutile ratio increases. OH radical generation from 18.4 % rutile TiO₂ nanotube plate was about 3.8 times higher than before annealing and 1.4 times higher than only 100 % anatase-TiO₂ nanotube. The efficiency of the 18.4% rutile TiO₂ nanotube was the best in comparison to TiO₂ nanotube with 18.4 %, 36.6 % and 98.6 % rutile. As a result, photocatalytic ability of 18.4 % rutile-TiO₂ nanotube plate was higher than 100 % anatase-TiO₂ nanotube plate.

• 한국정보통신학회논문지
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• 제15권1호
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• pp.169-174
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• 2011

짧은 바깥쪽 탄소 나노튜브를 가진 이중벽 탄소 나노튜브 공진기의 경우, 자유로운 끝은 긴 안쪽 벽의 진동에 중요한 역할을 한다. 짧은 안쪽 탄소 나노튜브를 가진 이중벽 카본 나노튜브 공진기의 경우, 안쪽은 부드러운 코어로 작동하여 기본 주파수가 이들의 길이에 의해 영향을 받는다. 본 논문에서는 서로 다른 길이를 가지고 나노튜브로 구성된 이중벽 탄소 나노튜브 공진기의 주파수 변화를 분석한다. 분석 결과, 안쪽 혹은 바깥쪽 탄소 나노튜브 길이를 제어하는 다양한 주파수 소자를 구현하는데 널리 응용될 수 있을 것으로 판단된다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2005년도 춘계학술대회논문집
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• pp.423-423
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• 2005

A carbon nanotube-based nanoelectromechanical device in resonance is examined theoretically. Mechanical deflections are electrically induced and resonantly excited at the fundamental frequency in cantilevered carbon nanotube. The electrically conducting elastic beam with van der Waals interactions at the tip is used for the modeling of the carbon nanotube device. Due to the elastic, electrical, and van der Waals interactions, the total energy of the system shows the unsymmetric two-well potentials. The predictions can be made that the device exhibits its nonlinear dynamic features in the two-well potentials. Also it is predicted that the fundamental frequency of the carbon nanotube device was changed by the nonlinear interactions induced by electrical and van der Waals potentials between carbon nanotube and ground surface of the device.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 춘계학술대회 논문집
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• pp.927-931
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• 2005

Carbon nanotube actuator, working under physical conditions (in aqueous solution) and converting electrical energy into mechanical energy directly, can be a good substitute for artificial muscle. The carbon nanotube actuator simulated in this paper is an isotropic cantilever type with an adhesive tape which is sandwiched between two single-walled carbon nanotubes. For predicting the static and dynamic characteristic parameters, the analytical model for a 3 layer bimorph carbon nanotube actuator is developed by using Euler-Bernoulli beam theory. The governing equation and boundary conditions are derived from energy principles. The induced displacements of the theoretical model are presented in order to investigate the performance of the carbon nanotube actuator with different control voltages. The developed model presents invaluable means for designing and predicting the performance of carbon nanotube actuator that can be used in artificial muscle applications.