• Journal of the Korean Society of Visualization
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• v.14 no.2
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• pp.52-60
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• 2016

The Passive Auxiliary Feedwater System(PAFS) is one of the advanced safety concepts adopted in the Advanced Power Reactor Plus(APR+). To validate the operational performance of the PAFS, detailed understanding of a boiling heat transfer on horizontal tube outside is of great importance. Especially, in the mechanistic boiling heat transfer model, it is important to visualize the phenomena but there are some limitations with conventional experimental approaches. In the present study, we devised a heater based on the Flexible Printed Circuit Board (FPCB) for a more comprehensive visualization and subsequently, a digital image processing technique for the bubble motion measurement was established. Using the measurement technique, important parameters of the nucleate boiling are analyzed.

• Journal of the Korean institute of surface engineering
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• v.50 no.6
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• pp.486-491
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• 2017

Silver nanowire (AgNW) transparent electrode is one of next generations of flexible and transparent electrode. The electrode shows high conductivity and high transparency comparable to ITO. However, the electrode is weak against heat. The wires are separated into nanodots at temperature above $200^{\circ}C$. It causes the electrical resistance increase. Moreover, it is vulnerable to oxygen and moisture in the atmosphere. The improvement of thermal and moisture resistance of silver nanowire transparent electrode is the most important for commercializing. We proposed silver nanowires transparent electrode which is capped with very thin nickel oxide layer. The nickel oxide layer is five nanometers of thickness, but the heat and moisture resistance of the transparent electrode is effectively improved. The AgNW/NiO electrode can endure at $300^{\circ}C$ of temperature for 30 minutes, and resistance is not increased for 180 hours at $85^{\circ}C$ of temperature and 85% of relative humidity. We showed an applications of transparent and flexible heater using the electrode, the heater is operated more than $180^{\circ}C$ of temperature.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.05a
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• pp.495-496
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• 2010

• Journal of the Microelectronics and Packaging Society
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• v.28 no.4
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• pp.73-77
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• 2021

Flexible electrodes for wearable devices have been actively studied in not only achieving mechanical/electrical stability, but also providing various functionalities for extending its industrial application. In this study, a flexible carbon/PDMS composite is prepared by addition of carbon black (CB) as a conductive filler, and effect of CB with different contents on electrical properties of the composite was investigated for the application of flexible electrodes, temperature sensor and heater. With increase of CB contents, resistivity of the carbon/PDMS was increased, and excellent durability was observed, confirmed by repetitive stretching deformation test. Resistance increase of the carbon/PDMS with temperature reveals the property of positive temperature coefficient, which can be applied for temperature sensor. Also, joule heating on the carbon/PDMS was observed when electrical potential was applied, indicating the applicability of the carbon/PDMS for heater.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.176.2-176.2
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• 2014

In this work, we demonstrated that the fabrication of flexible graphene-based chemical sensor with heaters by soft lithographic patterning method [1]. First, monolayer and multilayer graphene were prepared by thermal chemical vapor deposition transferred onto SiO2 / Si substrate in order to fabrication of patterned-sensor and -heater. Second, patterned-monolayer and multilayer graphene were detached through soft lithography process, which was transferred on top and bottom sides of PET film. Third, Au / Ti (Thickness : 100/30 nm) electrodes were deposited end of the patterned-graphene line by sputtering system. Finally, we measured sensor properties through injection of NO2 and CO2 gas on different temperature with voltage change of graphene heater.

• Journal of the Korean Society of Mechanical Technology
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• v.13 no.3
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• pp.107-111
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• 2011

This carbon nano heating system was consisted of power supply equipment, a carbon fiber and a stainless flexible hose. carbon nano heating system was manufactured by carbon fiber of a power capacity 30kw/h and light-oil hot air heater in control plot was the heating capacity 30,000kcal/h, As the result, Temperature difference due to carbon nano heating system and hot air heater in greenhouse showed that air temperature at experimental greenhouse, comparison greenhouse were $14.8^{\circ}C$, $13.4^{\circ}C$ respectively. It was found that carbon nano heating system and light-oil hot air heater heating cost were 1,095,740won, 2,683,628won. therefore as heating cost saving 60%. Yield of tomatoes cultured in greenhouse using carbon nano heating pipe was 4% inclease. Economic analysis comparison between the carbon nano heating pipe and the hot air heater in greenhouse were 41% respectively.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.30 no.8
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• pp.530-534
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• 2017

Transparent film heaters employing silver nanowires (Ag NWs) have attracted increasing attention because of their widespread applications. However, the low thermal resistance of Ag NWs limits the maximum operating temperature of the Ag NW film heater. In this study, Ag NW film heaters with high mechanical and thermal stability were successfully developed. The thermal power-out characteristics of the Ag NW heaters were investigated as a function of the Ag NW density. The results revealed that the prepared flexible Ag NW heater possessed high thermal stability over $190^{\circ}C$ owing to ZnO encapsulation. This indicates that the Ag NW film with excellent thermal stability have remarkably high potential for use as electrodes in film heaters operating at high temperatures.

• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.1233-1236
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• 2008

This study presents the fabrication process and display characteristics of a flexible organic polymer display device that consists of a thin substrate of Polyether Sulfone, a multilayer serpentine-type microheater array that is fabricated on the substrate, and a UV-sensitive polydiacetylene (PDA)-polyvinyl alcohol (PVA) composite film. A retention time of one second is achieved with cell sizes of $500{\mu}m$ and $700{\mu}m$ with cell-to-cell distances of $100{\mu}m$ and $200{\mu}m$, respectively.

• Bulletin of the Korean Space Science Society
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• 2008.10a
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• pp.29.1-29.1
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• 2008

The temperature control system which is using liquid and gaseous nitrogen has been known as the most economical system to simulate space temperature condition due to relatively not expansive price of the liquid nitrogen (less than 0.2 USD per liter). And, among these systems, the closed loop system which circulates compressed nitrogen gas come from sprayed liquid nitrogen by blower and makes a target temperature with heat from an electrical heater and flow rate of liquid nitrogen is prevail all over the world. But, this complete closed loop system requires expansive equipments such as blower, heater, and liquid nitrogen injector, and special maintenance on the system. Therefore, KARI is developing efficient and simple open loop system which utilizes liquid and gaseous nitrogen with eliminating a special blower and other expansive units. In this study, this open loop system with more efficiency and flexibility will be designed and introduced.

• Journal of the Korean Applied Science and Technology
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• v.32 no.3
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• pp.405-411
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• 2015

Carbon composites for flexible fiber heating element were examined to improve the electrical conductivity in this study. Carbon composites using carbon black, denka black, super-c, super-p with/without CNF or dispersant such as BCS03 and Sikament-nn were prepared. Carbon composite slurry was coated on plane film and yarns(cotton, polyester) and the performances of prepared heating materials were investigated by checking electrical surface resistance, adhesion strength. The plane heating element using carbon black under natural drying condition($25^{\circ}C$) had better physical properties such as surface resistance(185.3 Ohm/sq) and adhesion strength(above 90%) than those of other carbon composite heating elements. From these results, polyester heating element coated by carbon black showed better electrical line resistance(33.2 kOhm/cm) than cotton heating element. Then, it was found that polyester heating element coated by carbon black with CNF(3 wt%) and BCS03(1 wt%) appeared best properties(0.604 kOhm/cm).