• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.11a
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• pp.624-628
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• 2011

To develop a pulse detonation engine, it needs to understand the mechanism of a detonation initiation, and establish the methods for measuring and analyzing the detonation phenomenon. In this study, DDT tube, which use oxygen-acetylene propellant mixture, were designed and manufactured, and the effect of equivalent ratio and Schelkin spiral on the characteristics of the detonation initiation were discussed.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.07a
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• pp.131-134
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• 2001

Vertically aligned carbon nanotubes are grown on iron-deposited silicon oxide substrates by thermal chemical vapor deposition of acetylene gas at the temperature range 750∼950$^{\circ}C$. As the growth temperature increases from 750 to 950$^{\circ}C$, the growth rate increases by 4 times and the average diameter also increases from 30 nm to 130 nm while the density increases progresively with the growth temperature and a higher degree of crystalline perfection can be achieved at 950$^{\circ}C$. This result demonstrates that the growth rate, diameter, density, and crystallinity of carbon nanotubes can be controlled with the growth temperature.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2001.04a
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• pp.136-139
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• 2001

In this study, we have examined potential degradation of MTBE (methy1 tert-butyl ether) by pure culture ENV425 and mixed culture isolated from gasoline contaminated soil using n-butane as the sources of carbon and energy. The results described in this study suggest that MTBE is degraded cometabolically by ENV425 and mixed culture grown n-butane, and the disappearance of TBA after complete degradation of MTBE suggest the further degradation of TBA. Butane and MTBE degradation was completely inhibited by acetylene, which indicated that both substrates were degraded by butane-utilizing bacteria. MTBE was degraded ENV425 and mixed culture grown n-butane, and TBA (tert-butyl alcohol) was produced as product of MTBE oxidation. TBA production was accounted 54.7% and 58.6% for MTBE oxidation by ENV425 and mixed culture, respectively. The observed maximal transformation yield (T$_{y}$) were 44.7 and 34.0 (nmol MTRE degraded/$\mu$mol n-butane Utilized) by ENV425 and mixed culture, respectively.y.

• 한국전기화학회:학술대회논문집
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• 2001.06a
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• pp.179-184
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• 2001

The diffusion layer within MEA(membrane electrode assembly) has been evaluated important factor for improvement of cell performance in DMFC. The diffusion layer in MEA structure leads to the reduction of catalyst loss in active catalysts layer as well as prevention of water-flooding in cathode. Cell performance is directly affected by interior properties of diffusion layer materials. Acetylene Black and $RuO_2$ with large pore size and low porosity compared to Vulcan XC-72R gave better performance caused by vigorous methanol diffusion and water removal. And $RuO_2$ as diffusion layer materials showed different behavior in anode and cathode compartment, that is, diffusion layers in anode and cathode side make methanol diffusion and water removal facilitate, respectively.

• The Korean Journal of Ceramics
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• v.4 no.1
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• pp.9-14
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• 1998

Diamond-like carbon(DLC) films were deposited on buffer-layered ZnS substrates by radio frequency plasma enhanced chemical vapor deposition(RF-PECVD) method. Ge and GeC buffer layera were used between DLC and ZnS substrates to promote the adhesion of DLC on ZnS substrates. Ge buffer layers were sputter deposited by RF magnetron sputtering and $GeC^1$ buffer layers were deposited by same method except using acetylene reactive gas. The relatinship between film properties and deposition conditions was investigated using gas pressure, RF power and dc bias voltage as PECVD parameters. The hardness of DLC films were measured by micro Vickers hardness test and the adhesion of DLC films on buffer-layered ZnS substrates were studied by Sebastian V stud pull tester. The optical properties of DLC films on butter-layered ZnS substrates were characterized by ellipsometer and FTIR spectroscopy.

• Carbon letters
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• v.1 no.3_4
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• pp.129-132
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• 2001

Carbonaceous thin films were prepared from acetylene and argon gases by plasma assisted chemical vapor deposition (Plasma CVD) at 873 K. The carbonaceous thin films were characterized by mainly Raman spectroscopy, and their electrochemical properties were studied by cyclic voltammetry and charge-discharge measurements in propylene carbonate (PC) solution. Raman spectra showed that crystallinity of carbonaceous thin films is correlated by the applied RF power. The difference of the applied RF power also affected on the results of cyclic voltammetry and charge-discharge measurements. In PC solution, intercalation and de-intercalation of lithium ion can occur as well as in the mixed solution of EC and DEC.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.23 no.5
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• pp.418-423
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• 2010

Carbon nanotubes (CNTs) were synthesized by Fe-catalytic chemical vapor deposition (CVD) method about $800^{\circ}C$. The influence of process parameters such as pretreatment conditions, gas flow ratio, processing time, etc on the growth of CNTs was investigated by field emission scanning electron microscopy, transmission electron microscopy, and Raman spectroscopy. Ammonia was added to acetylene source gas before and during the CNT growth. Different types of CNTs formed depending upon the processing condition. It was found that ammonia prevented amorphous carbons from adsorbing to the outer wall of CNT, resulting in purification of CNTs during CNT growth.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.401-404
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• 2003

This paper investigates the effect of plasma treatment of aluminum on the fracture toughness of aluminum/CFRP composites, The surface of the aluminum panel was treated by a DC plasma. The plasma treatment was carried out at volume ratio of acetylene gas to nitrogen gas of 5:5 and the treatment times used was 30 sec. The fracture toughness of plasma-treated aluminum/CFRP' composites was compared with that of untreated aluminum/CFRP composites and The fracture surface of aluminum/CFRP composites was compared with SEM. The results showed that fracture toughness of plasm-treated aluminum/CFRP composites was about 50% higher than that of untreated aluminum/CFRP composites.

• Journal of Industrial Technology
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• v.5
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• pp.73-79
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• 1985

Thermodynamic calculation for the CVD of SiC from methyltrichlorosilane(MTS) was done in some range of deposition condition to identify optimum condition. The results show that the most considerable chemical species are chloride and chlorosilane for silicon source and methane and acetylene for carbon source. In order to yield single phase ${\beta}$-SiC it is believed that optimum temperature range is between 1500 and $1700^{\circ}k$. With increasing temperature, stable phase is changed from Si+SiC phase to C+SiC phase. It is believed because equilibrium concentration of silicon source decrease and equilibrium concentration of carbon source increases with increasing temperature.

• Journal of the Korean Society for Heat Treatment
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• v.23 no.2
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• pp.75-82
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• 2010

A new advanced combined PVD/CVD technique of DLC film deposition has been developed. Deposition of a DLC film was carried out using a pulsed carbon arc discharge in vapor hydrocarbon atmosphere. The arc plasma enhancing CVD process promotes dramatic increase in the deposition rate and decrease of compressive stress as well as improvement of film thickness uniformity compared to that obtained with a single PVD pulsed arc process. The optical spectroscopy investigation reveals great increase in radiating components of $C_2$ Swan system molecular bands due to acetylene molecules decomposition. AFM, Raman spectroscopy, XPS and nano-indentation were used to characterize DLC films. The method ensures obtaining a new superhard DLC nano-material for deposition of protective coatings onto various industrial products including those used in medicine.