http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
강성식(Sungsik Kang),오영근(Younggeun Oh),김선웅(Suneung Kim),이준희(Junhee lee) 한국자동차공학회 2018 한국자동차공학회 학술대회 및 전시회 Vol.2018 No.11
The head restraints are safety devices to protect head-neck injuries from car crash accidents, especially in rear-end collisions. Manufacturers are reporting an increased number of complaints from consumers, who find that head restraints’ design is not comfortable, so the new design standard of head restraint and seat back is investigated in this paper. Our statistical analysis results show the new standard is effective for seat comfort.
강정호,염정국,하종률 東亞大學校 大學院 2005 大學院論文集 Vol.30 No.-
A CNG fuel is one of the most promising alternative fuels because of lower exhaust emissions and lower CO2 emission with high thermal efficiency. However, the brake horse power is reduced because a CNG fuel has a low volumetric efficiency due to the gaseous charge and increase in time loss with lower burning speed as compared with gasoline fuel. To solve these problems, the DI Diesel Engine was modified to the DI CNG Engine which directly supplies natural gas into the engine cylinder. The combustion characteristics of the DI CNG engine such as cylinder pressure, cycle variation, combustion duration and emissions were investigated in this study. Consequently, it could be verified that the volumetric efficiency, overall combustion duration and lean limit were improved by using DI technique in the CNG Engine.
Kim, Sungsik,Kang, Phil Hyun,Nho, Young Chang,Yang, O-Bong 한국공업화학회 2003 응용화학 Vol.7 No.2
The irradiation is usually employed in sterilizing and crosslinking method of ultra-high molecular weight polyethylene (UHMWPE) bearing parts in orthopedic implants. The free radicals were formed in UHMWPE during this process in addition to crosslinking. The formed free radicals cause oxidative degradation of PE molecules by the reaction with oxygen during shelf storage and implantation in a long period. Electron spin resonance spectroscopic study was undertaken to investigate the remaining free radicals in UHMWPE after electron beam (EB) irradiation up to 500 kGy in N₂ environment. The heat treatment was employed at 110℃ and 145℃ for varying period of time to scavenge the free radicals. The free radicals were rapidly decayed for one hour and gradually decayed as a function of time by heat treatment than 110℃. Therefore longer heat treatment was required to scavenge all the free radicals formed in UHMWPE at 110℃. The oxidation profiles showed that the oxidation index (OI) of the heat-treated UHMWPE was lower than the OI of non heat-treated UHMWPE. The heat treatment of irradiated UHMWPE can substantially reduce the concentration of free radicals: thereby the UHMWPE has resistance against long-term oxidative degradation.
Kim, Sungsik,Kang, Phil Hyun,Nho, Young Chang,Yang, O-Bong Wiley Subscription Services, Inc., A Wiley Company 2005 Journal of applied polymer science Vol.97 No.1
<P>If a large amount of polymer radicals remain trapped after the irradiation of ultrahigh molecular weight polyethylene (UHMWPE), the radicals may result in a significant alteration of its physical properties during long-term shelf storage and implantation. An electron spin resonance spectroscopic study was undertaken to investigate the remaining free radicals in UHMWPE after electron beam irradiation up to 500 kGy in air and an N<SUB>2</SUB> environment. Heat treatment was employed at 110 and 145°C for various periods of time to decay the free radicals. The free radicals were rapidly decayed for 1 h and gradually decayed as a function of time with the heat treatment. The decay of the free radicals was completed more rapidly with a heat treatment at 145°C than at 110°C. Therefore, a longer heat treatment time is required to scavenge all the free radicals formed in UHMWPE at 110°C. The oxidation profiles showed that the oxidation index of the heat-treated UHMWPE was lower than the oxidation index of the non-heat-treated UHMWPE. The heat treatment of irradiated UHMWPE can substantially reduce the concentration of free radicals; therefore, UHMWPE has resistance against long-term oxidative degradation. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 103–116, 2005</P>
Observation of free radicals on electron beam irradiated UHMWPE by electron spin resonance
Kim, Sungsik,Kang, Phil Hyun,Nho, Young Chang,Yang, O-Bong 한국공업화학회 2003 응용화학 Vol.7 No.2
Electron spin resonance (EST) spectroscopic study was undertaken to investigate the remaining radicals in ultra-high molecular weight polyethylene. (UHMWPE) after electron beam (EB) irradiation up to 500 kGy in N₂ or air environment. The free radical concentration (FRC) as a function of dose and the decay of radicals as a function of storage time were observed by the change of EAT spectra. The FRC gradually increases with irradiation dose and the FRC of irradiation in N₂ is a little higher than irradiation in air. It is accepted that irradiation of UHMWPE produces alkyl radicals(-ㆍCH-CH₂-), which gradually transform to more stable ally radicals(-ㆍCH-CH=CH-).