• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1997.11a
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• pp.317-320
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• 1997

The paper reports on a study of the influence of the size of the particles of alumina trihydrate(ATH) filler on the surface aging characteristics of ehylene propylene diene terpolymer(EPDM). A fixed 100pph concentration of the filler of ATH was used (or all particle sizes from 0.7 to 20$\mu\textrm{m}$, It is show that hysteresis of contact angle and leakage current increase with increasing particle size, whereas tracking resistance decrease with increasing particle size.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2010.11a
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• pp.692-693
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• 2010

In this study, we analyze the combustion characteristic of GOx/PE hybrid rocket, by changing port diameter of the propellant. To study combustion characteristics of hybrid rocket, GOx is used for oxidizer and PolyEthylene is used for solid propellant. Regression rate and O/F ratio of the rocket is measured and presented.

• Food Science and Preservation
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• v.5 no.3
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• pp.247-255
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• 1998

This study was carried out to investigate changes in the flesh firmness, evolution of ethylene, cell wall components, and degradation and solubilization of polyuronide(PU) and polysaccharide(PS) in green(GP) and mature persimmon(MP) fruits according to testing time of ethylene(50${\mu}\ell$ㆍL$^{-1}$ ). When ethylene was treated in GP and MP, flesh firmness rapidly decreased and it was decreased more GP than MP. When ethylene were treated for 12 hours in GP, production of ethylene began after 3 days. The amount of ethylene product was maximum 16,000 ${\mu}\ell$ㆍL$^{-1}$ at 24 hours of ethylene treatment. However, ethylene was not producted until 7 days after 24 hours ethylene treatment at MP. The content of pectic substances decreased in the distilled- water, 0.05M $Na_2$CO$_3$,4M and 8M KOH-soluble fractions during softening according to increasing time of ethylene treatment. Arabinose and galactose were the major non-cellulosic neutral sugars in the 0.05M CDTA and 0.05M $Na_2$CO$_3$-soluble pectic fractions. Glucose, galactose and xylose were the major non-cellulosic neutral sugars in the 4M KOH- soluble hemicellulosic fraction. High molecular of PU and PS were degraded and solubilized in the distilled-water, 0.05M CDTA 0.05M $Na_2$CO$_3$ and 4M KOH-soluble fractions during time of ethylene treatment.