• Journal of the Korean Vacuum Society
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• v.17 no.6
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• pp.576-581
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• 2008

High-quality double-walled carbon nanotubes (DWNTs) were synthesized without defects and amorphous carbonaceous particles by catalytic decomposition method at $800^{\circ}C$ in high yield. As-synthesized carbon materials almost consist of DWNT bundles with a diameter 12 - 20 nm.. The DWNTs rope have uniform diameter about 2 - 5 um and length up to several tens micrometer. DWNTs is inner tube diameter 0.9 - 1.5 nm and outer tube 1.6 - 2.2 nm. We investigate the crystallinity of DWNTs by TEM and Raman spectroscopy. We also found that the Fe-Mo bimetallic catalyst was active as a very efficient catalyst for the synthesis of DWNTs with the catalyst decomposition method. Our results also indicate that Tetra Hydro Furan (THF) is a very ideal carbon source for the synthesis of DWNTs.

• Coupled systems mechanics
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• v.10 no.1
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• pp.39-60
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• 2021

The present paper is concerned with the study of nonlinear ultrasonic waves in a magneto thermo (MT) elastic armchair single-walled carbon nanotube (ASWCNT) resting on polymer matrix. The analytical formulation is developed based on Eringen's nonlocal elasticity theory to account small scale effect. After developing the formal solution of the mathematical model consisting of partial differential equations, the frequency equations have been analyzed numerically by using the nonlinear foundations supported by Winkler-Pasternak model. The solution is obtained by ultrasonic wave dispersion relations. Parametric work is carried out to scrutinize the influence of the non local scaling, magneto-mechanical loadings, foundation parameters, various boundary condition and length on the dimensionless frequency of nanotube. It is noticed that the boundary conditions, nonlocal parameter, and tube geometrical parameters have significant effects on dimensionless frequency of nano tubes. The results presented in this study can provide mechanism for the study and design of the nano devices like component of nano oscillators, micro wave absorbing, nano-electron technology and nano-electro- magneto-mechanical systems (NEMMS) that make use of the wave propagation properties of armchair single-walled carbon nanotubes embedded on polymer matrix.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2005.04a
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• pp.226-230
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• 2005

This paper presents the actuation performance of a conducting shape memory polyurethane (CSMPU) actuator. We introduced a concept of shape memory polyurethane activated by electric power while conventional shape memory polyurethanes are activated by external heat source. A conducting shape memory polyurethane actuator was manufactured by adding cabon nano-tube to conventional shape memory polyurethane. The main problem of the previous CSMPU was bad dispersion of carbon nano-tubes in polyurethane. In this paper, we have tried to find manufacturing method to solve the dispersion problem. With a lot of elaborative works, we have developed conducting shape memory polyurethane actuator with good electrical performance. The actuation performance of the developed conducting shape memory polyurethane actuator was measured and assessed.

• Carbon letters
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• v.9 no.4
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• pp.294-297
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• 2008

A CNT-$TiO_2$ nano composite was prepared from titanium chloride ($TiCl_4$) via sol-gel process using multi walled carbon nano tube (MWCNT) followed by calcination at $450^{\circ}C$. Spectral analysis revealed that the formed $TiO_2$ resided on the carbon in anatase form. The effect of adsorption was investigated using aqueous solution of methylene blue and procion blue dye. The photochemical reaction of CNT-$TiO_2$ composite in aqueous suspensions was studied under UV illumination in batch process. The reaction was investigated by monitoring the discoloration of the dyes employing UV-Visible spectro-photometeric technique as a function of irradiation time. The catalyst composites were found to be efficient for the photodegradation of the dye.

• Journal of IKEEE
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• v.27 no.1
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• pp.65-70
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• 2023

More than 10,000 Carbon NanoTube Field Effect Transistors (CNTFETs), which have advantages such as high carrier mobility, large saturation velocity, low intrinsic capacitance, flexibility, and transparency, have been successfully integrated into one semiconductor chip using conventional semiconductor design procedures and manufacturing processes. Three-dimensional multilayer structure of the CNTFET semiconductor chip and various CNTFET manufacturing process research increase the possibility of making the hybrid MOSFET-CNTFET semiconductor chip which combines conventional MOSFETs and CNTFETs together in a semiconductor chip. This paper discusses a methodology to design 6T binary SRAM using hybrid MOSFET-CNTFET. By utilizing the existing MOSFET SRAM or CNTFET SRAM design method, we will introduce a method of designing a hybrid MOSFET-CNTFET SRAM and compare its performance with the conventional MOSFET SRAM and CNTFET SRAM.

• Advances in nano research
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• v.12 no.3
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• pp.253-261
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• 2022

Numerical modelling of an integrated Carbon NanoTube (CNT) membrane is only achievable if probable deformations and realistic alterations from a perfect CNT membrane are taken into account. Considering the possible forms of CNTs, bending is one of the most probable deformations in these high aspect ratio nanostructures. Hence, investigation of effect associated with bent CNTs are of great interest. In the present study, molecular dynamics simulation is utilized to investigate fluid flow dynamics in deformed CNT membranes, specifically when the tube cross section is not affected. Bending in armchair (5,5) CNT was simulated using Tersoff potential, prior to flow rate investigation. Also, to study effect of inclined entry of the CNT to the membrane wall, argon flow through generated inclined CNT membranes is examined. The results show significant variation in both cases, which can be interpreted as counter-intuitive, since the cross section of the CNT was not deformed in either case. The distribution of fluid-fluid and fluid-wall interaction potential is investigated to explain the anomalous behavior of the flow rate versus bending angle.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.10
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• pp.1876-1882
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• 2008

Nano manipulator is used to manufacture Carbon NanoTube(CNT) tips. Using nano manipulator, operator attaches a CNT at the apex of Atomic Force Microscope(AFM) tip, which requires a mastery of mechanics and long manufacture time. Nano manipulator is installed inside a Scanning Electron Microscope(SEM) chamber to observe the operation. This paper presents a control scheme for horizontal axes of nano manipulator via processing SEM image. Edges of AFM tip and CNT are first detected, and the position information so obtained is fed to control horizontal axes of nano manipulator. That is, a visual servoing loop is realized to control the axes more precisely in nano scale.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.11a
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• pp.244-244
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• 2009

Carbon nanotubes (CNTs) have excellent electrical, chemical stability, mechanical and thermal properties. In this paper, networks of Multi-walled carbon nanotube (MWCNT) materials were investigated as transparent electrode. Sensor films were fabricated by air spray method using the multi-walled CNTs solution on glass substrates. The film that was sprayed with the MWCNT dispersion for 60 sec, was 300nm thick. And the electric resistivity and the light transmittance rate are $2{\times}10^2{\Omega}cm$ and 60%, respectively.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.171-171
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• 2011

Co and Fe doped multi-wall carbon nano-tubes (MWCNTs) synthesized by microwave plasma enhanced chemical vapor deposition (PECVD) technique are investigated with synchrotron radiations at Pohang Light Source (PAL) and European Synchrotron Radiation Facility (ESRF). Near edge x-ray absorption spectroscopy (NEXAFS) measurement at C K, Co $L_{3,2}$ and Fe $L_{3,2}$-edges, and x-ray magnetic circular dichroism (XMCD) at Co and Fe $L_{3,2}$-edges have been carried at 7B1 XAS KIST and 2A MS beamline, respectively, to understand the electronic structure and responsible magnetic interactions at room temperature. X-ray absorption spectroscopy (XAS) at C K-edge shows significant p-bonding and Co and Fe L-edges proves the presence of $Co^{2+}$ and $Fe^{2+}$ in octahedral symmetry. Co and Fe doped MWCNTs show good XMCD spectra at 300K. The effect on the magnetism is also studied through swift heavy ion (SHI) radiations and magnetism is found enhanced and change in the electronic structure in Co-CNTs is investigated.

• JSTS:Journal of Semiconductor Technology and Science
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• v.7 no.3
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• pp.133-139
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• 2007

Future MEMS systems will be composed of larger varieties of devices with very different functionality such as electronics, mechanics, optics and bio-chemistry. Integration technology of heterogeneous devices must be developed. This article first deals with the current development trend of new fabrication technologies; those include self-assembling of parts over a large area, wafer-scale encapsulation by wafer-bonding, nano imprinting, and roll-to-roll printing. In the latter half of the article, the concept towards the heterogeneous integration of devices and functionality into micro/nano systems is described. The key idea is to combine the conventional top-down technologies and the novel bottom-up technologies for building nano systems. A simple example is the carbon nano tube interconnection that is grown in the via-hole of a VLSI chip. In the laboratory level, the position-specific self-assembly of nano parts on a DNA template was demonstrated through hybridization of probe DNA segments attached to the parts. Also, bio molecular motors were incorporated in a micro fluidic system and utilized as a nano actuator for transporting objects in the channel.