• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2001년도 하계종합학술대회 논문집(2)
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• pp.145-148
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• 2001

In this paper, polycrystalline silicon thin film transistor using by Solid Phase Crystallization(SPC) were fabricated, and these devices were measured and analyzed the electrical output and transfer characteristics along to DC voltage stress. The transfer characteristics of polycrystalline silicon thin film transistor depended on drain and gate voltages. Threshold voltage is high with long channel length and narrow channel width. And output characteristics of polycrystalline silicon thin film transistor flowed abruptly much higher drain current. The devices induced electrical stress are decreased drain current. At last, field effect mobility is the faster as channel length is high and channel width is narrow.

• International Journal of Air-Conditioning and Refrigeration
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• 제9권2호
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• pp.19-27
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• 2001

In the present study, the effects of film Reynolds number (60∼200) and volumetric content of non-absorbable gases (0∼10%) in water vapor on the absorption process of aqueous LiBr solution were investigated experimentally. The formation of solution film on the horizontal tubes of six rows was observed to be complete for Re>100. Transition film Reynolds number was found to exist above which the Nusselt number and Schmidt number diminishes with solution flow rate. As the concentration of non-absorbable gases increased, mass transfer rate decreased more seriously than heat transfer rate did. the degradation effects of non-absorbable gases seemed to be significant especially when small amount of non-absorbable gases was introduced to the pure water vapor.

• 한국재료학회지
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• 제24권3호
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• pp.135-139
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• 2014

To obtain the transistor with ambipolar transfer characteristics, IGZO/SiOC thin film transistor was prepared on SiOC with various polarities as a gate insulator. The interface between a channel and insulator showed the Ohmic and Schottky contacts in the bias field of -5V ~ +5V. These contact characteristics depended on the polarities of SiOC gate insulators. The transfer characteristics of TFTs were observed the Ohmic contact on SiOC with polarity, but Schottky contact on SiOC with low polarity. The IGZO/SiOC thin film transistor with a Schottky contact in a short range bias electric field exhibited ambipolar transfer characteristics, but that with Ohmic contact in a short range electric field showed unipolar characteristics by the trapping phenomenon due to the trapped ionized defect formation.

• 설비공학논문집
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• 제12권2호
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• pp.218-225
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• 2000

In the present study, the effects of film Reynolds number (60∼200) and volumetric content of non-absorbable gases (0∼10%) in water vapor on the absorption process of aqueous LiBr solution were investigated experimentally. The formation of solution film on the horizontal tubes of six rows were observed to be complete for Re>100. Transition film Reynolds number were found to exist above which the Nusselt number and Schmidt number diminishes with solution flow rate. As the concentration of non-absorbable gases increased, mass transfer rate decreased more seriously than heat transfer rate did. The degradation effects of non-absorbable gases seemed to be significant especially when small amount of non-absorbable gases were introduced to the pure water vapor.

• 태양에너지
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• 제18권4호
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• pp.49-57
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• 1998

In this study, thin film evaporation of water on a horizontal plain tube is experimentally investigated. At a high heat flux, boiling of water is noticed inside the film. Once boiling occurs, evaporation heat transfer coefficient increases as the heat flux increases. In the non-boiling region, however, the heat transfer coefficient remains uniform irrespective of the heat flux. In this region, the heat transfer coefficient increases as the film flow rate increases. Comparison with existing correlations is also provided.

• 대한설비공학회지:설비저널
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• 제14권2호
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• pp.87-97
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• 1985

Experimental measurements of the heat flux to a upward impinging water jet on high heated test surface were obtained in the transition and film boiling regimes. Test variables were nozzle outlet velocity, subcooled water temperature and height of supplementary water. Boiling curve of this investigation is similar to a pool boiling curve, but it has one or two cap-shaped peaks in the transition regime. In the film boiling regime, the heat transfer rates are increased along with the increment of nozzle outlet velocity and subcooled temperature. There is optimum height of supplementary water for the augmentation of heat transfer Generalized correlations of boiling heat transfer are presented for maximum heat flux, minimum heat flux and $q_c$ at each supplementary height.

• 한국추진공학회지
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• 제16권5호
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• pp.37-46
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• 2012

로켓엔진 연소실에서 막냉각을 고려한 열전달 해석을 위한 모델을 수립하였다. 연소실 내에서의 대류, 복사, 막냉각 효과는 로켓엔진을 위한 경험식을 사용하였으며, 벽 외부는 일반적인 대류, 복사 식을 적용하였다. 또한 벽 내부는 유한체적의 격자를 구성하여 시간전진법에 의해 비정상 열해석을 수행하였다. 연소압 50 기압의 액체산소/케로신 엔진을 예로 해석하였으며, 이 경우 4% 유량의 막냉각까지는 벽온도를 낮추는데 크게 기여하였으나, 그 이상의 공급은 막냉각 유량에 비해 효과가 미비함을 확인하였다.

• International Journal of Air-Conditioning and Refrigeration
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• 제8권2호
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• pp.51-59
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• 2000

The purpose of the present study is to investigate the absorbing characteristics in a vertical falling film type absorber using LiBr-H$H_2O$ solution as working fluids with the concentration of 60 wt%. The experimental apparatus consists of an absorber with the diameter of 17.2 mm and the length of 1150 mm, a generator, an evaporator (condenser), a weak solution tank and a sampling trap device and so on. The parameters were the solution temperatures of 45 and 50$^{\circ}$C, coolant temperatures of 30 and 35$^{\circ}$C, and the film Reynolds numbers from 50 to 150. The pressure drop in the absorber increased as the solution and coolant temperatures decreased. The pressure drop in the absorber increased up to the film Reynolds number of 90, however, decreased at the film Reynolds number above 90. The maximum absorption mass flux was observed at the film Reynolds number of 90. Absorption mass fluxes increased as the coolant temperature decreased. Accordingly, absorption mass fluxes and heat transfer coefficients under the subcooled condition increased more than those under the superheated condition. It is claimed that heat transfer coefficients are deeply affected by the solution temperature more than the coolant temperature within the experimental range.

• 한국표면공학회지
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• 제55권3호
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• pp.173-179
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• 2022

This study presents a roll-to-roll process which is capable of Ag nanowire (AgNW) transfer from polyethylene terephthalate (PET) film to polycarbonate (PC) film. We developed a roll-to-roll machine that consists of two film suppliers, a coater of photo-curable resin, a film laminator, an ultraviolet (UV) exposure unit, and a film winder to facilitate large-area electrode transfer between different flexible substates. Using the process, optimal fabrication condition was investigated by parametric experiments in terms of the UV exposure time, number of thermal cycling, and exposure time of high temperature and humidity. A fabricated AgNW on PC film showed sheet resistance of 52 Ω/sq and optical transmittance of approximately 80 % over a range of visible light.

• 한국분무공학회지
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• 제22권3호
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• pp.129-136
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• 2017

Effects of collision angle on heat transfer characteristics of a liquid droplet impinging on a heated wall above the Leidenfrost point temperature were experimentally investigated. The heated wall and droplet temperatures were $506^{\circ}C$ and $100^{\circ}C$, respectively, and the impact angle varied from $20^{\circ}$ to $90^{\circ}$ while the normal collision velocity was constant at 0.27 m/s. The droplet collision behaviors and the surface temperature distribution were measured using synchronized high-speed video and infrared cameras. The major physical parameters influencing upon droplet-wall collision heat transfer, such as residence time, wall heat flux, effective heat transfer area, heat transfer amount, were analyzed. It was found at the constant normal collision velocity that the residence time, wall heat flux and effective heat transfer area were hardly not changed, resulting in the almost constant heat transfer amount.