• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.11 no.3
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• pp.414-421
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• 1999

Falling film rectification involves simultaneous heat and mass transfer between vapor and liquid interface. In the present work, the adiabatic rectification process of ammonia-water vapor on the vertical plate was investigated. The continuity, momentum, energy and diffusion equations for the solution film and vapor mixture were formulated in integral forms and solved numerically. The model could predict the film thickness, the pressure gradient, and the mass transfer rate. The effects of Reynolds number and ammonia concentration of solution and vapor mixture, rectifier length, and the enhancement of mass transfer in each phases were investigated. The stripping of water in vapor mixture occurred new the entrance of ammonia solution, which imposed the proper size of an adiabatic rectifier. Rectifier efficiency increased as film Reynolds number increased and as vapor mixture Reynolds number decreased. The improvement of rectifier efficiency was significant with the enhancement of mass transfer in falling film.

• Proceedings of the Materials Research Society of Korea Conference
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• 1995.11a
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• pp.41-41
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• 1995

• Proceedings of the Korean Vacuum Society Conference
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• 2003.08a
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• pp.146-146
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• 2003

• Proceedings of the Materials Research Society of Korea Conference
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• 1996.05a
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• pp.58-58
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• 1996

• 한국전기화학회:학술대회논문집
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• 1999.04a
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• pp.58-58
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• 1999

• Proceedings of the Korean Vacuum Society Conference
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• 1992.07a
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• pp.38-38
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• 1992

• Journal of Korean Vacuum Science & Technology
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• v.1 no.1
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• pp.24-29
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• 1997

Surface morphologies and fundamental characteristics of molybdenum nitride films deposited by reactive dc magnetron sputtering were studied for application to Cu diffusion barrier. A phase transformation from Mo to $\gamma$-Mo$_2$N phase at 0.5$N_2$ flow ratio.($N_2$/(Ar+$N_2$)) equal to and larger than 0.2, whereas a second phase transformation to $\gamma$-MoN phase at 0.5 N2 flow ratio, With the variation of the N2 ratio the surface morphologies of the films were generally smooth except the cases of 0.2 and 0.3$N_2$ gas rations, where build-up of film stresses occurred. $\gamma$-Mo$_2$N film was found to crystallize at the deposition temperature of 40$0^{\circ}C$. The surfaces of $\gamma$-Mo$_2$N films deposited up to 40$0^{\circ}C$ were smooth, but the film deposited at 50$0^{\circ}C$ had very rough surface morphology. It seems that this was due to the building-up of thermal stresses at the high deposition temperature, which might lead to hillock formation.

• Proceedings of the KIEE Conference
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• 2000.07c
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• pp.1625-1627
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• 2000

Cu(InGa)$Se_2$(CIGS) thin film absorbers with various Cu/(In+Ga) atomic ratios were prepared by a three-stage process using a co-evaporation appartus. The effect of Na on the structural and electrical properties of CIGS films were studied and their effects on the CIGS/Mo thin film solar cells were investigated. Soda-lime glass and Corning glass were used as substrates to compare the effect of Na diffusion into CIGS film. The resistivity of CIGS films was not changed in the Cu-poor lesion due to diffusion of Na from soda-lime glass but was mainly determined by the surface resistivity controlled by excess Na.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.11 no.12
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• pp.1139-1145
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• 1998

In this paper, to fabricate a superconducting fault current limiter(FCL) of thick film type, $YBa_2Cu_3O_X superconducting thick films were fabricated by surface diffusion process using the screen printing method. Powder mixture of $3BaCuO_2$+2CuO was screen printed on $Y_2BaCuO_5$(d=15mm). And critical current densities of the thick films were observed as the sintering temperature(92$0^{\circ}C$~95$0^{\circ}C$) and holding time(2h~10h). Based on experimental data, the thick films for superconducting FCL were sintered at $940^{\circ}C$ in 2 hours. The superconducting FCL with a current limiting area of 1mm wide and 66mm long was prepared on $Y_2BaCuO_5$ substrate. To measure the characterization of the fabricated FCL, an alternating voltage (60Hz) was applied to the FCL in 77K liquid nitrogen. At an applied voltage of 4V, the FCL was limited from 20A into 0.6A not farther than 0.5ms.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.16 no.10
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• pp.942-951
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• 2004

This paper presents the results of a theoretical study of the effect of radiation during free convective laminar film boiling for methanol/water binary mixtures on an isothermal vertical wall at atmospheric pressure. With the well-known boundary layer theory as a basis, a theoretical model has been formulated into consideration for mass diffusion at liquid phase. The equations are numerically solved by a similarity method to investigate the effects of radiation emissivity on the surface with various parameters such as wall superheat and composition of more volatile component at liquid phase far from the wall. From the results, the distributions of the physical quantifies are investigated in both phases. New correlations are proposed to predict the heat transfer coefficient of binary mixtures. It is shown that the proposed correlations are in good agreement with numerical results and with Bromley's correlation within maximum $11\%$ errors. It is also found that as the wall superheat is increased, radiation effect becomes more important.