• 유체기계공업학회:학술대회논문집
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• 2005.12a
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• pp.825-828
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• 2005

Experimental and numerical study was done to confirm the effect of the flexible tube in pipeline on transient flow oscillation. Experiment was made for a pipeline with and without deformable flexible tube using a single pumping system of main stainless pipe. The wave speeds of main pipe and flexible tube were calculated from the pipe material properties, structures, and boundary conditions. Time dependent pressure fluctuations were calculated for the pipeline using the simple and the Kelvin-Voigt viscoelastic models for the deformation of main pipe and flexible tube. Pressure calculated by the Kelvin-Voigt viscoelastic model showed better agreement with measured one than pressure by the simple model. Experimental and numerical results show that the maximum pressure as well as amplitude of pressure oscillation was decreased by inserting short flexible tube in pipeline. Hence, inserted short flexible tube to pipeline was found to be effective for the suppression of strong pressure oscillation. Moreover, the wave speed in pipe was discussed based on numerical and experimental results.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.37 no.2
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• pp.223-229
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• 2024

Laser-induced plasmonic sintering of metal nanoparticles (NPs) holds significant promise as a technology for producing flexible conducting electrodes. This method offers immediate, straightforward, and scalable manufacturing approaches, eliminating the need for expensive facilities and intricate processes. Nevertheless, the metal NPs come at a high cost due to the intricate synthesis procedures required to ensure long-term reliability in terms of chemical stability and the prevention of NP aggregation. Herein, we induced the self-generation of metal nanoparticles from Ag organometallic ink, and fabricated highly conductive electrodes on flexible substrates through laser-assisted plasmonic annealing. To demonstrate the practicality of the fabricated flexible electrode, it was configured in a mesh pattern, realizing multi-touchable flexible touch screen panel.

• Structural Engineering and Mechanics
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• v.53 no.1
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• pp.159-172
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• 2015

This paper is concerned with effects of the wall flexibility on the seismic behavior of ground-supported cylindrical silos. It is a well-known fact that almost all analytical approximations in the literature to determine the dynamic pressure stemming from the bulk material assume silo structure as rigid. However, it is expected that the horizontal dynamic material pressures can be modified due to varying horizontal extensional stiffness of the bulk material which depends on the wall stiffness. In this study, finite element analyses were performed for six different slenderness ratios according to both rigid and flexible wall approximations. A three dimensional numerical model, taking into account bulk material-silo wall interaction, constituted by ANSYS commercial program was used. The findings obtained from the numerical analyses were discussed comparatively for rigid and flexible wall approximations in terms of the dynamic material pressure, equivalent base shear and bending moment. The numerical results clearly show that the wall flexibility may significantly affects the characteristics behavior of the reinforced concrete (RC) cylindrical silos and magnitudes of the responses under strong ground motions.

• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.86-88
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• 2008

Organosiloxane based spin on planarizing dielectrics (PTS-E and PTS-R) were developed for application in flat panel displays as a replacement to conformal chemical vapor deposited SiNx. Here we demonstrate the successful use of siloxane-based material as a passivation layer for active matrix $\alpha$-Si thin film transistors (TFT) on both rigid and flexible substrates.

• ETRI Journal
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• v.37 no.2
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• pp.387-394
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• 2015

A novel interconnection technology based on a 52InSn solder was developed for flexible display applications. The display industry is currently trying to develop a flexible display, and one of the crucial technologies for the implementation of a flexible display is to reduce the bonding process temperature to less than $150^{\circ}C$. InSn solder interconnection technology is proposed herein to reduce the electrical contact resistance and concurrently achieve a process temperature of less than $150^{\circ}C$. A solder bump maker (SBM) and fluxing underfill were developed for these purposes. SBM is a novel bumping material, and it is a mixture of a resin system and InSn solder powder. A maskless screen printing process was also developed using an SBM to reduce the cost of the bumping process. Fluxing underfill plays the role of a flux and an underfill concurrently to simplify the bonding process compared to a conventional flip-chip bonding using a capillary underfill material. Using an SBM and fluxing underfill, a $20{\mu}m$ pitch InSn solder SoP array on a glass substrate was successfully formed using a maskless screen printing process, and two glass substrates were bonded at $130^{\circ}C$.

• Journal of the Korean Society of Industry Convergence
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• v.20 no.3
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• pp.233-243
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• 2017

This paper proposes a structure of direct-printed flexible tactile-sensor. These flexible tactile sensors are based on pressure-sensing materials that allow pressure to be measured according to resistance change that in turn results from changes in material size because of compressive force. The sensing material consists of a mixture of multi walled carbon nanotubes (MWCNTs) and TangoPlus, which gives it flexibility and elasticity. The tactile sensors used in this study were designed in the form of array structures composed of many lines so that single pressure points can be measured. To evaluate the performance of the flexible tactile sensor, we used specially designed signal-processing electronics and tactile sensors to experimentally verify the sensors' linearity. To test object grasp, tactile sensors were attached to the surface of the fingers of grippers with three degrees of freedom to measure the pressure changes that occur during object grasp. The results of these experiments indicate that the flexible tactile sensor-based robotic gripper can grasp objects and hold them in a stable manner.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.06a
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• pp.44-44
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• 2009

Recently, transparent ZnO-based TFTs have attracted much attention for flexible displays because they can be fabricated on plastic substrates at low temperature. We report the fabrication and characteristics of ZnO channel layers(ZnO TFTs) having different channel thicknesses. The ZnO film were deposited as active channel layers on $Si_3N_4/Ti/SiO_2p$-Si substrates by rf magnetron sputtering at $100\;^{\circ}C$ without additional annealing. Also the Zno thin films deposited at oxygen partial pressures of 40%. ZnO TFTs using a bottom-gate configuration were investigated. The $Si_3N_4$ film were deposited as gate insulator by PE-CVD at $15\;^{\circ}C$. All Processes were processed below $150^{\circ}C$ which is optimal temperature for flexible display and were used dry etching method.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.19 no.7
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• pp.687-694
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• 2006

We report on the fabrication of organic-based flexible displays using an amorphous IZO anode grown at room temperature. The IZO anode films were grown by a conventional DC reactive sputtering on the polycarbonate (PC) substrate at room temperature using a synthesized IZO target in a $Ar/O_2$ ambient. Both x-ray diffraction (XRD) and high resolution electron microscope (HREM) examination results show that the IZO anode film grown at room temperature Is complete amorphous structure due to low substrate temperature. A sheet resistance of $35.6\Omega/\Box$, average transmittance above 90 % in visible range, and root mean spare roughness of $6\sim10.5\AA$ were obtained even in the IZO anode film grown on PC substrate at room temperature. It is shown that the $Ir(ppy)_3$ doped flexible organic light emitting diode (OLED) fabricated on the IZO anode exhibit comparable current-voltage-luminance characteristics as well as external quantum efficiency and power efficiency to OLED fabricated on conventional ITO/Glass substrate. These findings indicate that the IZO anode film grown on PC substrate is a promising anode materials for the fabrication of organic based flexible displays.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.19 no.12
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• pp.1134-1139
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• 2006

Electrical, optical, and structural properties of indium zinc oxide (IZO) anode films grown by a RF magnetron sputtering were investigated as functions of RF power and working pressure in pure Ar ambient. To investigate electrical, optical and structural properties of IZO anode films, 4-point probe and UV/VIS spectrometry, and X-ray diffraction (XRD) were performed, respectively. A sheet resistance of $15.2{\Omega}/{\square}$, average transmittance above 80 % in visible range, expecially above 85 % in 550 nm, and root mean square roughness of 1.13 nm were obtained from optimized IZO anode films grown in oxygen free ambient. All samples show amorphous structure regardless of RF power and working pressure due to low substrate temperature. In addition, XPS depth profile obtained from IZO/PES exhibits that there is no obvious evidence of interfacial reaction between IZO and PES substrate. Furthermore, current-voltage-luminance of the flexible phosphorescent flexible OLEDs fabricated on IZO anode shows dependence on sheet resistance of the IZO anode. These results indicate that the IZO anode is a promising candidate to substitute conventional ITO anode for high-quality flexible displays.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.06a
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• pp.491-492
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• 2006

We report on the fabrication of organic-based flexible display using an amorphous IZO anode grown at room temperature. The IZO anode films were grown by a conventional DC reactive sputtering on polycarbonate (PC) substrate at room temperature using a synthesized IZO target in a Ar/$O_2$ ambient. X-ray diffraction examination results show that the IZO anode film grown at room temperature is complete amorphous structure due to low substrate temperature. It is shown that the $Ir(ppy)_3$ doped flexible organic light emitting diode (OLED) fabricated on the IZO anode exhibit comparable current-voltage-luminance characteristics to OLED fabricated on conventional ITO/glass substrate. These findings indicate that the IZO anode film grown on PC substrate is a promising anode materials for the fabrication of organic based flexible displays.