• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.23 no.6
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• pp.413-420
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• 2011

Thermodynamic cycles using binary mixtures as working fluids offer a high potential for utilization of low-temperature heat sources. This paper presents a thermodynamic performance analysis of Goswami cycle which was recently suggested to produce power and cooling simultaneously and combines the Rankine cycle and absorption refrigeration cycle by using ammoniawater mixture as working fluid. Effects of the system parameters such as concentration of ammonia and turbine inlet pressure on the system are parametrically investigated. Results show that refrigeration capacity or thermal efficiency has an optimum value with respect to ammonia concentration as well as to turbine inlet pressure.

• The KSFM Journal of Fluid Machinery
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• v.14 no.2
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• pp.41-46
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• 2011

This study investigated the changes in performance and operating characteristics of an F-class gas turbine according to the change of working fluid from air to carbon dioxide. The revised gas turbine is the topping cycle of the semi-closed oxy-fuel combustion combined cycle. With the same turbine inlet temperature, the $CO_2$ gas turbine is expected to produce about 85% more power. The main contributor is the greater compressor mass flow and the added oxygen flow for the combustion. Compressor pressure ratio increases about 50%. However, the gas turbine efficiency reduces about 10 %. Modulation of inlet guide vane to reduce the compressor inlet mass flow, the major purpose of which is to reduce the compressor inlet Mach number, was also performed.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.17 no.12
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• pp.1277-1282
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• 2004

ITO films on PET substrate were prepared by DC magnetron sputtering method using powdery target with different deposition conditions. In addition, the electrical and optical properties were investigated. As the sputtering power and working pressure were higher, the resistvity of ITO films increased. The optical transmittance deteriorated with increasing sputtering power and thickness. As the working pressure increased, however, the optical transmittance improved at visible region of light. From these results, we could deposited ITO films with 8${\times}$10$^{-3}$ $\Omega$-cm of resistivity and 80 % of transmittance at optimal conditions.

• Proceedings of the International Microelectronics And Packaging Society Conference
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• 2000.04a
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• pp.97-102
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• 2000

We have studied etching characteristic of Ta film using Electron Cyclotron Resonance (ECR) etcher system. Microwave source power. RF bias power. and working pressure were varied to investigate the etch Profile. And we have used two step etching method to acquire the goWe have studied etching characteristic of Ta film using Electron Cyclotron Resonance (ECR) etcher system. Microwave source power. RF bias power. and working pressure were varied to investigate the etch Profile. And we have used two step etching method to acquire the good etch profile preventing the microloading effect.od etch profile preventing the microloading effect.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.11 no.4
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• pp.125-130
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• 2012

When conducting a powder blasting to a spinning cylindrical workpiece in the codition of 0.76~1.5(mm) in nozzle size, 1~5(atm) in working pressure, and 40~100(mm) in stand off distance, the value of surface roughness becomes under $0.283{\mu}m$, which is not enough to expand a bonding area. In the case of horizontal transfer blasting with 0.76mm of nozzle size, 100mm of stand off distance, and 2~5atm of working pressure, $0.5{\sim}0.7{\mu}m$ of surface roughness has achieved regardless of feed rate.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.342.2-342.2
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• 2014

IZO, ITO, ITO 등의 투명전극들 중 Indium Tin Oxide (ITO) 다른 전극에 비해 높은 광투과도와 낮은 저항으로 인하여 다양한 부분에서 널리 이용되고 있다. 본 연구에서는 우수한 투과도의 멀티 layer 단열 창호를 위한 film 개발을 위해 RF magnetron system을 이용하여 Sodalime Glass와 polyethylene terephthalate (PET) substrate에 ITO를 증착함으로써 전기적 광학적 특성을 조사하였다. 실험은 power 변화와 Ar, O2의 가스 분압비, Working Pressure의 변화를 변수로 두어 진행하였다. 측정은 Ellipsometry를 이용하여 광학적인 두께와 굴절률을 조사하였고 UV visible spectrometer를 통해 광학적인 투과도를 확인하였다. Power는 100 Watt 늘려가며 진행하였고 O2 유량의 변화에 따라 투과도와 면저항, 굴절률 특성이 달라짐을 확인할 수 있었다. O2의 유량에 따라 면저항이 줄어들다가 어느 정도 이상이 되면 급격히 증가함을 확인할 수 있었다. Working Pressure 변화에 따른 전기적 광학적 특성 또한 확인 하였다.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.341.2-341.2
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• 2014

산화물 반도체는 가시광선 영역인 380~780 nm 부근에서의 투과율이 80% 이상이고, 3.2 eV 이상의 band gap과 높은 mobility를 가지는 물질로서 투명한 스마트 창호필름이나 디스플레이에 유망한 물질로 연구되고 있다. 본 연구에서는 스마트 윈도우에 적용되는 높은 가시광 투과율과 적외선 차단을 위한 필름개발을 목적으로 산화물 반도체인 $TiO_2$ 물질을 RF Sputter를 이용하여 상온에서 박막성장을 하였다. Glass와 PET 위에 동시에 성장시켜 각각의 기판에 성장된 $TiO_2$ 박막의 물리적인 성질 등을 조사하였다. 측정은 Ellipsometry를 이용하여 광학적인 두께와 굴절률을 조사하였고 UV visible spectrometer를 통해 광학적인 투과도를 확인하였다. 100Watt 부터 RF power를 높여가며 Working Pressure 변화변 주었을 때 낮은 RF power와 Working Pressure에서 높은 가시광 투과율을 확인 할 수 있었다.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.316-316
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• 2014

Two different transparent conducting oxide (TCO) layers of Al-doped ZnO (AZO) and $WO_3$ were prepared by a rf sputtering process. Working pressure, deposition time, and target-to-substrate distance were varied for the sputtering process to improve electrical properties of the resulting layer. Thickness of the TCO layers was measured by a profile meter of ${\alpha}$-step. To evaluate the electrical conductivity, surface resistivity of the TCO layers was measured by a four-point probe technique. Decrease of the working pressure resulted in increase of deposition rate and decrease of surface resistivity of the resulting layer. Increase of the layer thickness due to increased deposition time resulted in decrease of surface resistivity of the resulting layer. The shorter the target-to-substrate distance was, the lower was the surface resistivity of the resulting layer.

• Journal of the Semiconductor & Display Technology
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• v.3 no.2
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• pp.17-21
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• 2004

Aluminum nitride(AlN) thin films were deposited on silicon substrate by reactive RF magnetron sputtering without substrate heating. We investigated the dependence of some properties for AlN thin film on sputtering conditions such as working pressure, $N_2$ concentration and RF power. XRD, Ellipsometer and AES has been measured to find out structural properties and preferred orientation of AlN thin films. Deposition rate of AlN thin film was increased with an increase of RF power and decreased with an increase of $N_2$ concentration. AES in-depth measurements showed that stoichiometry of Aluminium and Nitrogen elements were not affected by $N_2$ concentration. It has shown that low working pressure, low $N_2$ concentration and high RF power should be maintained to deposit AlN thin film with a high degree of (0002) preferred orientation.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.15 no.10
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• pp.828-834
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• 2003

A diffusion absorption refrigerator is a heat-generated refrigeration system. It uses a three-component working fluid consisting of the refrigerant (ammonia), the absorbent (water) and the auxiliary gas (hydrogen or helium). In this study, experimental investigations have been carried out to examine the effects of charging conditions of working fluids on the evaporating temperature for diffusion absorption refrigerator. Experimental parameters considered in the present experiments are charging concentration, solution charge and system pressure determined by auxiliary gas charged. As a result, in the charging condition of 35% of concentration and 20 kg$_{f}$cm$^2$ of system pressure, the system has the lowest evaporating temperature. It was found that there exists a minimum value of solution charge for the operation of diffusion absorption refrigerator.r.