• Journal of the Korean Society of Clothing and Textiles
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• v.45 no.4
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• pp.674-684
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• 2021

Recent advances in electronic technology have engendered a need for research on the use of smart materials in clothing. Electro-conductive fibers are expected to be a crucial element of wearable devices. Therefore, in this study, we have attempted to develop electro-conductive threads and cables using silver nanowires. Based on the characteristics of silver nanowire, in which electro-conductivity can be imparted via heat treatment, we prepared conductive threads by coating nylon yarn with silver nanowires and curing at temperatures of 140℃, 150℃, and 160℃. Conductive threads cured at 140℃ had the highest conductivity, followed by threads cured at 160℃ and 150℃ respectively. The order of the electrical conductivity of the threads after tensile testing was consistent with the original order of the conductivity of the threads. When we evaluated the sensing performance of electro-conductive cables fabricated from these threads, the cables manufactured from threads cured at 140℃ and 160℃ were found to function normally within temperature and humidity sensors. All the cables operated normally in illuminance and electrocardiogram sensors. Thus, we believe that threads made of silver nanowire have sufficient electrical conductivity to be utilized as wearable sensors.

• Applied Chemistry for Engineering
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• v.21 no.5
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• pp.500-504
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• 2010

The PU-g-MWNTs/PU film was synthesized by simple blending method to fabricate composites which have excellent mechanical and electrical properties. PU-g-MWNTs based composite revealed much enhanced dispersity than pristine MWNTs composite because of interfacial interaction related with interfacial compatibility between polymer matrix and PU on the MWNTs surface. The electro-conductivity of composite was measured as a function of PU-g-MWNTs concentration. The results were correlated with percolation threshold theory. As a result, the critical concentration and exponent of electro-conductivity behavior was equal to 0.78 wt% and 0.945.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.09a
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• pp.1002-1007
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• 2010

This study evaluates the electro-osmotic hydraulic conductivity for the clay specimen by applying the series of the voltage gradient simultaneously with different stress conditions. The test results shows that the shrinkage of voids corresponds to the linear decrease in the electro-osmotic seepage velocity, and the changes of electro-chemical characteristics in the specimen induces the gradual decrease of the electro-osmotic seepage velocity with the constant voltage gradient.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.04a
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• pp.22-22
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• 2006

• Journal of the Korean Society of Visualization
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• v.3 no.2
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• pp.45-50
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• 2005

Electro-osmotic flow (EOF) instability in a microchannel has been experimentally investigated using a micro-PIV system. The micro-PIV system consisting of a two-head Nd:Yag laser and cooled CCD camera was used to measure instantaneous velocity fields and vorticity contours of the EOF instability in a T-shape glass microchannel. The electrokinetic flow instability occurs in the presence of electric conductivity gradients. Charge accumulation at the interface of conductivity gradients leads to electric body forces, driving the coupled flow and electric field into an unstable dynamics. The threshold electric field above which the flow becomes unstable and rapid mixing occurs is about 1000V/cm. As the electric field increases, the flow pattern becomes unstable and vortical motion is enhanced. This kind of instability is a key factor limiting the robust performance of complex electrokinetic bio-analytical devices, but can also be used for rapid mixing and effective flow control fer micro-scale bio-chips.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.19 no.1
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• pp.1-6
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• 2008

A wearable T-matching dipole UHF RFID tag antenna has been designed using conductive electro-thread. The conductivity of the electro-thread has been measured depending on the number of twisted thread. The measured conductivity has been used for simulation to have accurate simulation results. The flexible electro-thread or fabric has been used for fabricating the antenna instead of using copper tape since the electro-thread is more flexible and wearable than copper tape. The return loss and reading range of the fabricated electro-thread UHF RFID tag antennas have been tested. The reading range is approximately 2.4 m.

• Journal of Environmental Science International
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• v.25 no.10
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• pp.1417-1426
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• 2016

Despite the low removal efficiencies reported by previous studies, electro-flotation still stands out among other microalgae removal methods for its economical and environmental benefits. To enhance removal efficiency, the important factors that limit the performance of this method must be investigated. In this study, the possible ways of increasing the removal efficiency of microalgae have been explored by investigating the effects of several important variables in electro-flotation. Eight parameters, namely flotation time, rising time, current density, pH, conductivity, electrode distance, temperature and initial concentration were evaluated using a one-parameter-at-a-time approach. Results revealed that the operational parameters that greatly affected the removal efficiency of microalgae were electro-flotation time, current density, pH, and initial concentration. The effect of conductivity, electrode distance, and temperature on removal efficiency were insignificant. However, they exhibited positive an indirect positive effect on power demand, which is nowadays considered an equally important aspect in the running of a feasible and economically efficient electro-flotation process.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.35 no.3
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• pp.246-254
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• 2022

Localized heat can be generated using electrically conductive word-lines built into a 3D NAND flash memory string. The heat anneals the gate dielectric layer and improves the endurance and retention characteristics of memory cells. However, even though the electro-thermal annealing can improve the memory operation, studies to investigate material failures resulting from electro-thermal stress have not been reported yet. In this context, this paper investigated how applying electro-thermal annealing of 3D NAND affected mechanical stability. Hot-spots, which are expected to be mechanically damaged during the electro-thermal annealing, can be determined based on understanding material characteristics such as thermal expansion, thermal conductivity, and electrical conductivity. Finally, several guidelines for improving mechanical stability are provided in terms of bias configuration as well as alternative materials.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.06a
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• pp.502-502
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• 2007

Current thin film process using memory device fabrication process use expensive processes such as manufacturing of photo mask, coating of photo resist, exposure, development, and etching. However, direct printing technology has the merits about simple and cost effective processes because inks are directly injective without mask. And also, this technology has the advantage about fabrication of fine pattern line on various substrates such as PCB, FCPB, glass, polymer and so on. In this work, we have fabricated the fine and thick metal pattern line for the electronic circuit board using metal ink contains Ag nano-particles. Metal lines are fabricated by two types of printing methods. One is a conventional printing method which is able to quick fabrication of fine pattern line, but has various difficulties about thick and high resolution DPI(Dot per Inch) pattern lines because of bulge and piling up phenomenon. Another(Second) methods is sequential printing method which has a various merits of fabrication for fine, thick and high resolution pattern lines without bulge. In this work, conductivities of metal pattern line are investigated with respect to printing methods and pattern thickness. As a result, conductivity of thick pattern is about several un.

• 한국신재생에너지학회:학술대회논문집
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• 2006.11a
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• pp.324-324
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• 2006

Nb and Ti were added to 316 stainless steel, and then heat-treatments and surface treatments were performed on the 316 stainless steel and the Nb- and Ti-added alloys. All samples indicated enhanced electrical conductivity after surface treatments, whereas they showed low electrical conductivity before surface treatments due to the existence of non-conductive passive film on the alloy surface. In particular, the Hb- and Ti-added alloys showed remarkable enhancement of electrical conductivity compared to the original alloy, 316 stainless steel. Surface characterization revealed that small carbide particles formed on the alloy surface after surface treatments, while the alloys indicated flat surface structure before surface treatments. $Cr_{23}C_6$ mainly formed on the 316 stainless steel, and NbC and TiC mainly formed on the Nb- and Ti-added alloys, respectively. We attribute the enhanced electrical conductivity after surface treatments to the formation of these carbide particles, possibly acting as a means of electro-conductive channel through the passive film. Furthermore, NbC and TiC are supposed to be more effective carbides than $Cr_{23}C_6$ as electro-conductive channels of stainless steel