• Composites Research
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• v.17 no.5
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• pp.68-77
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• 2004

The electromagnetic (EM) absorption or shielding characteristics of a material is an important issue not only for military purpose but also for commercial purposes such as radar, electric or telecommunication devices. In order to design the effective electromagnetic wave absorber, the electromagnetic characteristics of the constituents of the material should be available in target frequency band. Also, it must be possible to predict the electromagnetic properties of absorbers with respect to the content of lossy ingredients. In this study, the dielectric properties of unsaturated polyester resins containing nano-size conductive carbon black powder were measured with a free space method in the X-band frequency range and analyzed with respect to the content of carbon black. Finally, the method for estimating the dielectric properties of polymeric resin containing conductive carbon black with respect to the EM frequency was developed and verified.

• Bulletin of the Korean Chemical Society
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• v.31 no.11
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• pp.3077-3083
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• 2010

The electrochemical detection of As(III) was investigated on a platinum-iron(III) nanoparticles modified multiwalled carbon nanotube on glassy carbon electrode(nanoPt-Fe(III)/MWCNT/GCE) in 0.1 M $H_2SO_4$. The nanoPt-Fe(III)/MWCNT/GCE was prepared via continuous potential cycling in the range from -0.8 to 0.7 V (vs. Ag/AgCl), in 0.1 M KCl solution containing 0.9 mM $K_2PtCl_6$ and 0.6 mM $FeCl_3$. The Pt nanoparticles and iron oxide were co-electrodeposited into the MWCNT-Nafion composite film on GCE. The resulting electrode was examined by cyclic voltammetry (CV), scanning electron microscopy (SEM), and anodic stripping voltammetry (ASV). For the detection of As(III), the nanoPt-Fe(III)/MWCNT/GCE showed low detection limit of 10 nM (0.75 ppb) and high sensitivity of $4.76\;{\mu}A{\mu}M^{-1}$, while the World Health Organization's guideline value of arsenic for drinking water is 10 ppb. It is worth to note that the electrode presents no interference from copper ion, which is the most serious interfering species in arsenic detection.

• Korean Journal of Materials Research
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• v.18 no.10
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• pp.564-570
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• 2008

Nanostructured carbon materials have been found to have applications in fuel cell electrodes, field emitters, electronic devices, sensors and electromagnetic absorbers, etc. Especially, the CNF (carbon nanofiber) can be expected to play an important role in catalyst supporters for fuel cell electrodes and chemical reactions. In this study, we synthesized CNF from a liquid phase carbon source by a solvothermal method. In addition, we studied the parameters for the preparation of CNF by controlling heating and cooling rates, synthesis temperature and time. We characterized the CNF by SEM/TEM, XRD, Raman spectroscopy and EDS. We found that the heating and cooling rate have strong effects on the CNF formation and growth. We were able to prepare the best CNF at the heating rate of $10^{\circ}$/min, at $450^{\circ}$ for 60 minutes, and at the cooling rate of $4^{\circ}$/min. As a result of Raman spectra, we found that the sample showed two characteristic Raman bands at ${\sim}1350cm^{-1}$ (D band) and ${\sim}1600cm^{-1}$ (G band). The G band indicates the original graphite feature, but the D band has been explained as a disorder feature of the carbon structure. The diameter and length of the CNF was about $15{\sim}20nm$, and over $1{\mu}$, respectively.

• Polymer(Korea)
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• v.26 no.3
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• pp.367-374
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• 2002

Electrical characteristics of crystalline polymer composites filled with nano-sized carbon black particle were studied. The developed composite system exhibited a typical positive temperature coefficient resistance (PTCR) characteristic, where the electrical resistance sharply increased at a specific temperature. The PTCR effect was sometimes followed by a negative temperature coefficient resistance (NTCR) feature with temperature, which seemingly caused by the coagulation of nano-sized carbon black particles in the excessive quantity. The PTCR temperature was controlled by the carbon black content and the external voltage. The change of electric conductivity was shown as a function of carbon black content, and the resistance was constant when the carbon black content was over 20 wt%. The room-temperature resistance was maintained by a repeated heating and cooling. The excellent PTCR characteristic was demonstrated by the low resistance in the initial stage and the instantaneous heating capability.

• 한국전기화학회:학술대회논문집
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• 2005.04a
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• pp.12-12
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• 2005

• Bulletin of the Korean Chemical Society
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• v.34 no.9
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• pp.2645-2649
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• 2013

We have developed a one-step synthesis of benzofurans from o-iodophenol and various terminal alkynes, by using Pd catalyst supported on nano-sized carbon balls (NCB) under copper- and ligand free conditions. This recyclable catalyst could be reused more than 5 times in the same heteroannulation reaction. The results have demonstrated that diverse 2-substituted benzofurans with tolerant functional groups can be prepared simply and conveniently under these conditions.

• Journal of Powder Materials
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• v.10 no.1
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• pp.1-5
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• 2003

Nano-sized WC powders were synthesized by vapor phase reaction using the precusor of tungsten ethoxide under helium and hydrogen atmosphere. The phases of the powder were varied with reaction Bone and gas flow rate. The powder size was about 30nm in diameter, and the tungsten carbide powder was coated by carbon layer. The synthesis of nano-sized WC powders was promoted as the hydrogen gas flow rate became higher. Inversely, tungsten oxide was formed by increasing the flow rate of helium gas. The synthesized powders were analyzed by XRD, FE-SEM, carbon analyzer etc.

• Journal of Powder Materials
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• v.16 no.2
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• pp.131-137
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• 2009

This paper deals with the effects of the surfactant and preplate process (sensitization and activation) on electroless copper plating on carbon nano-fiber (CNF). Ultrasonic irradiation was applied both during dispersion of CNF and during electroless plating containing preplate process. The dispersion of CNF and flatness of the plated copper film were discussed based on the changes in surfactant concentration and preplate process time. It was clearly shown that high concentration of surfactant and long time of preplate process could promote the agglomeration of CNF and uneven copper plating on CNF.

• Journal of the Korean Applied Science and Technology
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• v.34 no.3
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• pp.595-601
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• 2017

In vivo assay of glucose detection was described using a skin tattoo film electrode (STF), and the probe was made from carbon nano tube paste modification film paper. Here in the square-wave stripping anodic working range obtained of $20-100mgL^{-1}$ within an accumulation time of 0 seconds only in sea water electrolyte solutions of pH 7.0. The relative standard deviations of 50 mg glucose that were observed of 0.14 % (n=12), respectively, using optimum stripping accumulation of 30 sec, the low detection limit (S/N) was pegged at 15.8 mg/L. The developed results can be applied to the detect of in vivo skin sensing in real time. Which confirms the results are usable for in vitro or vivo diagnostic clinical analysis.

• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.1594-1597
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• 2008

Carbon nanotube (CNT) cathodes were fabricated using nano-sized silver powders as a bonding material. The effects of powder size on the field emission properties for the CNT cathode were investigated The better emission properties of CNT cathodes using smaller particles are due to a low sintering temperature of the bonding materials.