• 한국자기공명학회논문지
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• 제19권1호
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• pp.11-17
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• 2015

The Kubo formalism and utilizing the projection operator technique (POT) introduced by Kawabata, the electron spin resonance (ESR) line-shape formula for carbon nanotubes through the hyperfine interaction introduced earlier in terms of POT. We can see that the line-width decreases exponentially as the temperature increases. The spin relaxation time show gradual decrease as magnetic field becomes larger. The analysis reveals the peculiarities in spin relaxation inherent to one dimensional system at low temperature and weak magnetic fields. Thus, the present technique is considered to be more convenient to explain the carbon nanotubes as in the case of other optical transitions.

• Advances in nano research
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• 제15권2호
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• pp.91-104
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• 2023

Development of thin carbon nanotubes (CNTs) nanoliquid film over the rough surface of a horizontal rotating disk is investigated by considering symmetric roughness either along the azimuthal or radial directions. The disk surface is either heated or cooled axisymmetrically from below. The effects of single-walled carbon nanotubes (SWCNTs), multi-walled carbon nanotubes (MWCNTs) are analyzed on the film thinning process with different types of base liquids. Closed form solutions for velocity and temperature field are obtained for small values of Reynolds number whereas the numerical solution is derived for moderate values of Reynolds number. It is found that fluid retention / depletion takes place when the roughness is symmetric along the azimuthal / radial directions. It is also seen that the film thinning rate enhances for MWCNTs compare to SWCNTs. Further it is found that two different heat transfer regions exits within the flow domain depending on the fact that heat is transferred from disk to liquid film and vice-versa.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2002년도 International Meeting on Information Display
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• pp.662-665
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• 2002

The growth of carbon nanotubes (CNTs) was carried out using ratio frequency plasma enhanced chemical vapor deposition (rf PECVD) system equipped with dc bias for the directional growth. Acetylene and ammonia gas were used as the carbon source and a catalyst. The relation between gas flow rate and dc bias on the growth of CNTs was investigated. We studied the relation between emission properties and the directionality of CNTs grown under different dc bias voltage.

• Carbon letters
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• 제14권3호
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• pp.175-179
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• 2013

Isolated single wall carbon nanotubes (SWCNTs) were synthesized by chemical vapor deposition (CVD) using a liquid precursor (xylene) as a carbon source. Transmission electron microscopy (TEM) and atomic force microscopy confirmed the isolated structure of the SWCNTs. Micro-Raman measurements showed a tangential G-band peak ($1590cm^{-1}$) and radial breathing mode (RBM) peaks ($150-240cm^{-1}$). The tube diameters determined from the RBM frequencies are in good agreement with those obtained from TEM. The chirality of the isolated SWCNTs could be determined based on the energy of the laser and their diameter. A further preliminary study on the nitrogen doping of isolated SWCNTs was carried out by the simple use of acetonitrile dissolved in the precusor.

• 대한화학회지
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• 제46권5호
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• pp.467-476
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• 2002

• 한국반도체및디스플레이장비학회:학술대회논문집
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• 한국반도체및디스플레이장비학회 2006년도 춘계학술대회
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• pp.105-108
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• 2006

We investigated the fluidic gas-driven carbon-nanotube motor based on multi-wall carbon nanotubes and fluidic gas flow. Since the origination of the torque was the friction between the carbon nanotube surface and the fluidic gases, the density and the flow rate of the working gas or liquid were very important for the carbon nanotube motor. Molecular simulation results showed that multi-wall carbon nanotubes with very low rotating energy barriers could be effectively used for fluidic gas-driven carbon-nanotube motors.

• Carbon letters
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• 제12권4호
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• pp.218-222
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• 2011

Well-aligned multi-walled carbon nanotubes (MWCNTs) were successfully synthesized by catalytic chemical vapor deposition using a hydrogen sulfide ($H_2S$) additive onto Al/Fe thin film deposited on Si wafers. Transmission electron microscopy images indicated that the as-grown carbon products were thin MWCNTs with small outer diameters of less than 10 nm. $H_2S$ plays a key role in synthesizing thin MWCNTs with a large inside hollow core. The well-aligned thin MWCNTs showed a low turn-on voltage of about 1.1 V/${\mu}m$ at a current density of 0.1 ${\mu}A/cm^2$ and a high emission current of about 1.0 mA/$cm^2$ at a bias field of 2.3 V/${\mu}m$. We suggest a possible growth mechanism for the well-aligned thin MWCNTs with a large inside hollow core.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2003년도 International Meeting on Information Display
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• pp.859-862
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• 2003

Well-aligned multiwall carbon nanotubes (MWCNTs) were prepared at low temperature of 400 $^{\circ}C$ by utilizing a radio frequency plasma-enhanced chemical vapor deposition (rf-PECVD) system. The MWCNTs were treated by an external rf plasma source and an ultra-violet laser in order to modify structural defect of carbon nanotube and to ablate possible contamination on carbon nanotube surface. Structural properties of carbon nanotubes were investigated by using a scanning electron microscopy (SEM), Raman spectroscopy, Fourier transformer Infrared spectroscopy (FTIR) and transmission electron microscope (TEM). In addition, the emission properties of the MWNTs were measured for the application of field emission display (FED) in near future. Various post treatments were found to improve the field emission property of carbon nanotubes.

• Advances in nano research
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• 제1권1호
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• pp.13-27
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• 2013

Carbon nanotube characterized by additional inductive effect as compared with the traditional conductors like copper wires of the same size. Consequently, carbon nanotubes have high characteristic impedance and slow wave propagation in comparison with traditional conductors. Due to these characteristics, carbon nanotubes can be used as antenna. In view of this, we describe and review the present research progress on carbon nanotube antennas. We present different analysis models and results which are developed to investigate the characteristics of CNT antennas. Then we conclude by summarizing the characteristics of CNT antennas and specifying the operating frequency limit.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2004년도 춘계학술대회논문집
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• pp.559-562
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• 2004

Carbon nanotube is a geometrical frame-like structure and the primary bonds between two nearest-neighboring atoms act like beam members, whereas an individual atom acts as the joint of the related beam members. The sectional property parameters of these beam members are obtained from molecular mechanics. Computations of the elastic deformation of single-walled carbon nanotubes reveal that the Young's moduli of carbon nanotubes vary with the tube diameter and are affected by their helicity. With increasing tube diameter, the Young's moduli of carbon nanotubes approach the Young's modulus of graphite.