• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.530-530
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• 2012

Many practical applications of carbon nanotubes(CNTs) have been proposed and there have been attempts to utilize CNT films as transparent electrodes for solar cells and displays. Our group has considered the use of the CNT film as a thin film heater (TFH) and proposed it for the first time and reported the thermal behavior of the TFH made of single walled CNTs. However, due to the relatively high electrical resistance of the CNT film, using the TFH in application areas requiring high heat flux has been a difficult problem. To overcome this obstacle, we adopted a 'branch electrodes' concept to increase the film conductance dramatically. If two branch electrodes are inserted into a TFH whose original electrical resistance is R, the total resistance will be reduced to R/9. Because of the increased aspect ratio, the resistance of each segmented TFH will be reduced to R/3. Furthermore, since they are connected in parallel, the total resistance reduces to R/9. This could be extended to n branch electrodes, and the total resistance of the film will be reduced to R/(n+1)2, if the resistance of electrodes are negligibly small. We fabricated the heaters with different number of branch electrodes. The number of branch electrodes of the fabricated heaters are 0, 2, 4, 8 and their electrical resistance are 101.4, 39.5, 20.0, $15.4{\Omega}$, respectively. We applied 20V to each heater and monitored the temperature variations. We could achieve high heating temperature even with low voltage supply. This technique could be applied to relevant industrial applications which need high power film heater.

• Toxicological Research
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• v.24 no.1
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• pp.23-28
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• 2008

Voltammetric analysis of mercury ions was developed using paste electrodes (PEs) with DNA and carbon nanotube mixed electrodes. The optimized analytical results of the cyclic voltammetry (CV) of the $1{\sim}14ng\;L^{-1}Hg(II)$ concentration and the square wave (SW) stripping voltammetry of the $1{\sim}12ng\;L^{-1}Hg(II)$ working range within an accumulation time of 400 seconds were obtained in 0.1 M $NH_4H_2PO_4$ electrolyte solutions of pH 4.0. For the relative standard deviations of the $1ng\;L^{-1}Hg(II)$, which were observed at 0.078% (n = 15) at the optimum conditions, the low detection limit (S/N) was pegged at $0.2ng\;L^{-1}(7.37{\times}10^{-13}M)$ for Hg(II). The results can be applied to assays in biological fish kidneys and wastewater samples.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.1535-1538
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• 2005

We present a mass productive and reproducible assembly technique of a single bundle of single-walled carbon nanotubes (sb-SWNTs) using dielectrophoresis (DEP). Gold electrodes with 10 gaps made via microlithography were used to align the carbon nanotubes (CNTs). The magnitude and type of applied electric field were investigated to verify their effects on CNT assembly. The optimum assembling conditions in which sb-SWNTs could be positioned at a desired site were experimentally identified, and the characteristics of the assembled sb-SWNTs were evaluated from AFM, Raman spectroscopy, and I-V curve. This assembly method has potential for applications such as gas sensors or electronic devices.

• Journal of Sensor Science and Technology
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• v.26 no.2
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• pp.73-78
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• 2017

A tetrode is one of the neural electrodes, and it is widely used to record neural signals in the brain of a freely moving animal. The impedance of a neural electrode is an important parameter because it determines the signal-to-noise ratio of the recorded neural signals. Here, we developed a modification technique using carbon nanotube-polypyrrole composite nanostructures to decrease the impedances of tetrodes. The synthesis of the carbon nanotube and polypyrrole nanostructures was performed in two steps. In the first step, randomly dispersed carbon nanotubes and pyrrole monomers were gathered and aligned on the tetrode electrode. Next, they were electro-polymerized on the electrode surface. As the applied time (step-1 and step-2) and the offset voltage increased, the impedances of the tetrodes decreased. The modification technique is, therefore, an important and useful of lowering the impedances of tetrodes.

• Transactions on Electrical and Electronic Materials
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• v.4 no.4
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• pp.26-29
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• 2003

To discover electrical properties of individual single wall nanotube(SWNT), a number of SWNT-based tubeFETs have been fabricated. The device consists of a single semiconducting SWNT on an insulating substrate, contacted at each end by metal electrodes. It presents high transconductances, and charge storage phenomenon, which is the operations of injecting electrons from the nanotube channel of a tubeFET into charge traps on the surface of the $SiO_2$ gate dielectric, thus shifting the threshold voltage. This phenomenon can be repeated many times, and maintained for the hundreds of seconds at room temperature. We will report this phenomenon as the memory effects of the SWNT, and attempt to use this property for the memory device.

• 한국생물공학회:학술대회논문집
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• 2005.10a
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• pp.1018-1018
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• 2005

• Carbon letters
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• v.10 no.2
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• pp.90-93
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• 2009

The excellent and characteristic capacitor performance of pure single-walled carbon nanotubes (SWNTs), which differ from conventional activated carbon electrodes, is reported. SWNTs with little bundling showed higher specific capacitance than activated carbons. High operating voltage can be expected for pure SWNTs without metal contamination and graphene edge structure.

• Korean Journal of Materials Research
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• v.21 no.3
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• pp.133-137
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• 2011

Gold have been used as an electrode materials having a good mechanical flexibility as well as electrical conductivity, however the stretchability of the gold on a flexible substrate is poor because of its small elastic modulus. To overcome this mechanical inferiority, the reinforcing gold is necessary for the stretchable electronics. Among the reinforcing materials having a large elastic modulus, carbon nanotube (CNT) is the best candidate due to its good electrical conductivity and nanoscale diameter. Therefore, similarly to ferroconcrete technology, here we demonstrated gold electrodes mechanically reinforced by inserting fabrics of CNTs into their bodies. Flexibility and stretchability of the electrodes were determined for various densities of CNT fabrics. The roles of CNTs in resisting electrical disconnection of gold electrodes from the mechanical stress were confirmed using field emission scanning electron microscope and optical microscope. The best mechanical stability was achieved at a density of CNT fabrics manufactured by 1.5 ml spraying. The concept of the mechanical reinforced metal electrode by CNT is the first trial for the high stretchable conductive materials, and can be applied as electrodes materials in various flexible and stretchable electronic devices such as transistor, diode, sensor and solar cell and so on.

• Proceedings of the Materials Research Society of Korea Conference
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• 2007.11a
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• pp.137.2-137.2
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• 2007

• Korean Chemical Engineering Research
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• v.46 no.5
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• pp.898-902
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• 2008

Prepared are three types of composite supercapacitor electrode, such as electroactive polyaniline(PAN), PAN/multi-walled carbon nanotube(CNT), and $CNT/PAN/RuO_2$. Cyclic voltammetry was performed to investigate the supercapacitive properties of these electrodes in an electrolyte solution of 1.0M $H_2SO_4$. The $CNT/PAN/RuO_2$ electrode showed the highest specific capacitance at all scan rates(e.g., 441 and $392F\;g^{-1}$ at 100 and $1,000mV\;s^{-1}$, respectively). In cycle performance, however, the PAN/CNT electrode demonstrated the best capacitance retention (66%) at $10^4th$ cycle.