• Journal of the Korean housing association
• /
• v.17 no.4
• /
• pp.101-109
• /
• 2006

The purpose of this study was to suggest ways on reducing the cooling and heating energy cost of the officetel building with the multiple glazing windows according to Life Cycle Costing. This study consisted of an hour-by hour energy simulation program and further data from the EnergyPlus V1-2-2 to the four pane type windows that were applied with 2 low-e polyester film and krypton gas to the officetel model building. It was determined that the four panes type windows that had 2 low-e polyester film and krypton gas applied to, them showed a cooling and heating cost reduction over traditional double glazed windows that were filled with air. According to this study, as well as the information from chart 4.5 and the LCC it was determined that the present value of the four panes of windows that had 2 low-e polyester film and krypton gas applied to them showed. a 11.4% reduction in heating and cooling in comparison to the traditional double glazed windows that were filled with air.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2012.08a
• /
• pp.210-210
• /
• 2012

Gas barrier coating from dense thin film deposition has been one of the important applications such as food-packaging and organic display. Especially for food-packaging, plastic container has been widely used due to its low price and high through-put in mass production. However, the plastic container with low surface energy like polypropylene (PP) has been limited to apply gas barrier coating. That is because a gas barrier coating could not adhere to PP due to its too low surface energy and high porosity of PP. In this research, we applied carbon coating consisting of Si and O as an interlayer between silicon oxide (SiOx) and PP. A carbon layer was found to provide better adhesion, which was experimentally proved by oxygen transmission rate (OTR) and SEM images. However, we also found that there is a limitation in the maximum thickness of a carbon layer and SiOx film due to their high stress level. For this conflict, we obtain the optimal thickness of a carbon layer and SiOx film showing optimal gas barrier property.

• Journal of the Korean Society for Precision Engineering
• /
• v.18 no.2
• /
• pp.119-125
• /
• 2001

This paper presents an experimental study on active control of self-excited vibration for a high speed turbomachinery. In order to suppress the self-excited vibration, it is necessary to actively control the air film pressure or the air film thickness. In this study, active pads are used to control the air film thickness. Active pads are supported by pivots containing piezoelectric actuators and their radial position can be actively controlled by applying voltage to the actuators. The transfer characteristics from actuator inputs to shaft vibration outputs are experimentally investigated. In a tilting-pad gas bearing (TPGB), a shaft is supported by the pressurized air film. Four gap sensors were used to measure the vibration of the shaft and PID was used in the feedback control of the shaft vibration. The experimental results show that the self-excited vibration of the rotor can be effectively suppressed if the PID controller gains are properly chosen. As a result we find that the feedback control is effective for suppressing the self-excited vibration of a rotor system using stack-type PZT actuators.

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.12 no.2
• /
• pp.34-40
• /
• 2013

Various depositional conditions, such as substrate, pressure, deposition time, temperature of substrate, power and gas composition, have mainly been studied to attain DLC films using RF sputtering system up to the current. In this study, the $N_2/Ar/CH_4$ gas mixture factored on characteristics of DLC deposited film such as structure, hardness, electrical property were investigated. The concentration of the $N_2$ gas in the sputtering gas may be a significant effect on the growth rate of the doped films, because nitrogen ions react not only with the carbon atoms on the target but also with $C_xH_y$ ions in the plasma on the substrate surface. It was seen from this experimental that the resistance of deposited film is decreased, and the relative intensity ratio of D to G peak is increased as nitrogen content of film deposition is increased.

• Electrical & Electronic Materials
• /
• v.9 no.1
• /
• pp.9-17
• /
• 1996

Plasma enhanced chemical vapor deposition (PECVD) allows low temperature processing and so it is widely used, but it causes instability of devices due to serious amount of impurities within the film. In this paper, electrical and chemical characteristics of the PECVD oxynitride film formed by different N$_{2}$O to N$_{2}$O+NH$_{3}$ gas ratio is studied. It has been found that hydrogen concentration of PECVD oxynitride film was decreased from 4.25*10$^{22}$ [cm$^{-2}$ ] to 1.18*10$^{21}$ [cm$^{-2}$ ] according to the increase of N$_{2}$O gas. It was also found that PECVD oxynitride films have low trap density in the oxide and interface in comparison with PECVD nitroxide films, and has higher refractive index and capacitance than oxide films. In particular, oxynitride film formed in gas ratio of N$_{2}$O/(N$_{2}$O+NH$_{3}$)= 0.88 shows increased capacitance and decreased leakage current due to small portion of hydrogen in oxide and the accumulation of nitrogen about 4[atm.%] at the interface.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.59 no.11
• /
• pp.2016-2020
• /
• 2010

Indium-zinc-oxide (IZO) films were deposited at room temperature via RF sputtering with varying the flow rate of additive nitrogen gas ($N_2$). Thin film transistors (TFTs) with an inverted staggered configuration were fabricated by employing the various IZO films, such as $N_2$-added and pure (i.e., w/o $N_2$-added), as active channel layers. For all the deposited IZO films, effects of additive $N_2$ gas on their deposition rates, electrical resistivities, optical transmittances and bandgaps, and chemical structures were extensively investigated. Transfer characteristics of the IZO-based TFTs were measured and characterized in terms of the flow rate of additive $N_2$ gas. The experimental results indicated that the transistor action occurred when the $N_2$-added (with $N_2$ flow rate of 0.4-1.0 sccm) IZO films were used as the active layer, in contrast to the case of using the pure IZO film.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2004.08a
• /
• pp.985-987
• /
• 2004

A plastic substrate for flexible display is developed. The gas barrier property in the substrate is improved through depositing metal and metal oxide multi layer on plastic film by PVD process. The metal/metal-oxide multiplayer on plastic film shows excellent gas barrier property and optical property.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2006.05a
• /
• pp.144-145
• /
• 2006

In this study, the Al doped ZnO thin films were prepared by the facing targets sputtering(FTS) apparatus. The electrical characteristics, transmittance of ITO thin films were investigated as a function of varying input current and oxygen gas flow rate. As a result, the ITO thin film was prepared with a resistivity $6{\times}10-4[{\Omega}-cm]$ and transmittance 80% at visible range.

• Journal of the Semiconductor & Display Technology
• /
• v.20 no.4
• /
• pp.157-160
• /
• 2021

As an insulator for a thin film transistor(TFT) and an encapsulation material of organic light emitting diode(OLED), aluminum oxide (Al₂O₃) has been widely studied using several technologies. Especially, in spite of low deposition rate, atomic layer deposition (ALD) has been used as a process method of Al₂O₃ because of its low process temperature and self-limiting reaction. In the Al₂O₃ deposition by ALD method, Ar Purge had some crucial effects on the film properties. After reaction gas is injected as a formation of pulse, an inert argon(Ar) purge gas is injected for gas desorption. Therefore, the process parameter of Ar purge gas has an influence on the ALD deposited film quality. In this study, Al₂O₃ was deposited on glass substrate at a different Ar purge time and its structural characteristics were investigated and analyzed. From the results, the growth rate of Al₂O₃ was decreased as the Ar purge time increases. The surface roughness was also reduced with increasing Ar purge time. In order to obtain the high quality Al₂O₃ film, it was known that Ar purge times longer than 15 sec was necessary resulting in the self-limiting reaction.

• The KSFM Journal of Fluid Machinery
• /
• v.12 no.3
• /
• pp.26-30
• /
• 2009

This paper predicts the critical speeds of a 5MW industrial gas turbine by using commercial rotordynamic tool, DYNAMICS 4.3. The gas turbine is operated at 12,975 rpm on squeeze film dampers. The stiffness of the squeeze film dampers are estimated. The critical speeds of the gas turbine rotor are calculated to have a sufficient separation margin (2%) from the 1st bending mode and pass over 2 rigid body modes below 4,000 cpm. This paper discussed the coupling effects on the dynamic response of the gas turbine.