• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.28 no.5
• /
• pp.510-517
• /
• 2004

A fine hot-wire is used both as a heating element and a temperature sensor in transient hot-wire method. The traditional sensor system is unnecessarily big so that it takes large fluid volume to measure the thermal conductivity. To dramatically reduce this fluid volume, a new sensor fabrication and a data processing method are proposed in this article. Contrast to the conventional and most popular two wire sensor, the new sensor system is made up of divided multiple long and short wires. Through validation experiments, it is found that the measured thermal conductivities of the glycerin are exactly same each other between the conventional and proposed new method. Also some technical considerations in arranging the multiple wires are briefly discussed.

• Proceedings of the KSME Conference
• /
• 2003.11a
• /
• pp.210-215
• /
• 2003

A fine hot-wire is used both as a heating element and a temperature sensor in transient hot-wire method. The traditional sensor system is unnecessarily big so that it takes large fluid volume to measure the thermal conductivity. To dramatically reduce this fluid volume, a new sensor fabrication and a data processing method are proposed in this article. Contrast to the conventional and most popular two wire sensor, the new sensor system is made up of divided multiple long and short wires. Through validation experiments, it is found that the measured thermal conductivities of the glycerin are exactly same each other between the conventional and proposed new method. Also some technical considerations in arranging the multiple wires are briefly discussed.

• Applied Chemistry for Engineering
• /
• v.31 no.3
• /
• pp.291-298
• /
• 2020

ZITO/Ag/ZITO multilayer transparent electrodes at room temperature on glass substrates were prepared using RF/DC magnetron sputtering. Transparent conductive films with a sheet resistance of 9.4 Ω/㎡ and a transmittance of 83.2% at 550 nm were obtained for the multilayer structure comprising ZITO/Ag/ZITO (100/8/42 nm). The sheet resistance and transmittance of ZITO/Ag/ZITO multilayer films meant that they would be highly applicable for use in polymer-dispersed liquid crystal (PDLC)-based smart windows due to the ability to effectively block infrared rays (heat rays) and thereby act as an energy-saving smart glass. Effects of the thickness of the PDLC layer and the intensity of ultraviolet light (UV) on electro-optical properties, photopolymerization kinetics, and morphologies of difunctional urethane acrylate-based PDLC systems were investigated using new transparent conducting electrodes. A PDLC cell photo-cured using UV at an intensity of 2.0 mW/c㎡ with a 15 ㎛-thick PDLC layer showed outstanding off-state opacity, good on-state transmittance, and favorable driving voltage. Also, the PDLC-based smart window optimized in this study formed liquid crystal droplets with a favorable microstructure, having an average size range of 2~5 ㎛ for scattering light efficiently, which could contribute to its superior final performance.

• Applied Chemistry for Engineering
• /
• v.33 no.1
• /
• pp.50-57
• /
• 2022

Ti-In-Zn-O (TIZO)/Ag/TIZO multilayer transparent electrodes were prepared on glass substrates at room temperature using RF/DC magnetron sputtering. Obtained multilayer structure comprising TIZO/Ag/TIZO (10 nm/10 nm/40 nm) with the total thickness of 60 nm showed a transmittance of 86.5% at 650 nm and a sheet resistance of 8.1 Ω/□. The multilayer films were expected to be applicable for use in energy-saving smart window based on polymer-dispersed liquid crystal (PDLC) because of their transmittance properties to effectively block infrared rays (heat rays). We investigated the effects of the content ratio of prepolymer, the thickness of the PDLC coating layer, and the ultraviolet (UV) light intensity on electro-optical properties, and the surface morphology of polyester acrylate-based PDLC systems using new TIZO/Ag/TIZO transparent conducting electrodes. A PDLC cell with a thickness of 15 ㎛ PDLC layer photocured at an UV intensity of 1.5 mW/cm² exhibited good driving voltage, favorable on-state transmittance, and excellent off-haze. The LC droplets formed on the surface of the polymer matrix of the PDLC composite had a size range of 1 to 3 ㎛ capable of efficiently scattering incident light. Also, the PDLC-based smart window manufactured using TIZO/Ag/TIZO multi-layered transparent electrodes in this study exhibited a light brown, which will have an advantage in terms of aesthetics.