• Journal of Photoscience
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• 제4권1호
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• pp.17-21
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• 1997

The photochemical reactions of the neat chloroform and the aqueous chloroform in the absence (saturated with argon) and presence of 02 (saturated with air or oxygen) have been investigated using 184.9 nm UV light. The irradiation of the deoxygenated neat chloroform causes the formation of hexachloroethane, pentachloroethane, and 1, 1, 2, 2-tetrachloroethane. The initial quantum yields of the products were determined to be 6.37 x 10$^{-4}$, 4.04 x 10$^{-4}$ and 1.76 x 10$^{-4}$, respectively. In the irradiation of aqueous chloroform, chloride ion was also formed along with the products listed above and 1, 1, 2, 2-tetrachloroethane was the predominant product among the chlorinated organic products, which contrasts to the case of the neat chloroform. The presence of oxygen during the irradiation of aqueous chloroform had an effect on the yield of the products. With increasing the concentration of oxygen, the formation of the products was decreased. Probable reaction mechanisms for the photochemical reaction were presented on the basis of products analysis.

• 동력기계공학회지
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• 제12권1호
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• pp.5-12
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• 2008

We measured emission characteristics of CRDI diesel engine equipped with a commercial CPF. Experimental parameters adopted a neat diesel fuel, a blend of diesel fuel with 20% biodiesel, a blend of diesel fuel with 15% biodiesel and 5% ethanol. The experiments were carried out to measure the emission and engine performance according to ESC 13-mode cycles. The maximum torque with biodiesel blend fuel is slightly lower than that of neat diesel fuel in the entire the 13-mode cycles, and 5% ethanol and 15% biodiesel blend fuel is slightly higher than that of neat diesel fuel. THC and CO emissions of the biofuel blended diesel fuel were slightly increased and decreased, and mean conversion efficiencies of THC and CO on the commercial CPF were achieved about 70$\sim$87% in the ESC 13-mode. From the measurement by the Scanning Mobility Particle Sizer(SMPS), the total number and mass of nano-sized particles by a commercial CPF were decreased about 97.8% and 96.8 % in the range of the nano-size from 10.6 to 385nm, respectively.

• Elastomers and Composites
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• 제46권3호
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• pp.257-261
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• 2011

새로운 아스팔트 개질 방법을 소개한다. 일반 아스팔트에 플라스틱 고분자의 단량체인 디메틸페놀(DMP)를 혼입하여 아스팔트 내부에서 외부의 반응촉매 투입 없이 공기 중의 산소분자에 의하여 열가소성 고분자인 폴리페닐렌 옥사이드(PPO)가 자율적으로 중합되면서 아스팔트의 소성변형 내구성이 크게 향상된 개질아스팔트를 얻었다. 인장실험에서, 아스팔트 내에서 생성된 PPO에 의해, 기계적 특성에서 가장 중요한 두 가지 요소인 티네시티와 터프네스가 순수 아스팔트보다 각각 두 배 반 그리고 세 배 가량 증가하였다.

• Kyungpook Mathematical Journal
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• 제21권1호
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• pp.31-37
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• 1981

• 천문학회보
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• 제34권2호
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• pp.31.1-31.1
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• 2009

• Kyungpook Mathematical Journal
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• 제29권2호
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• pp.125-131
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• 1989

• Transactions on Electrical and Electronic Materials
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• 제13권2호
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• pp.89-92
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• 2012

The effect of organic impurities on the electrical properties of a neat epoxy resin was studied. 0.05, 0.5 and 1.0 phr of iso-propyl alcohol (IPA) and methylene chloride (MC) mixture (50/50 wt%) were used as impurities. The current density, volume resistance and impedance characteristics of the epoxy/IPA/MC systems were measured with a high voltage source meter and broadband dielectric spectroscopy. Glass transition temperature (Tg) was measured by a differential scanning calorimetry (DSC) and it was found that Tg decreased slightly with increasing IPA/MC content. It was also found that Tg values of the epoxy systems with various IPA/MC contents were closely related to the current density, volume resistance and impedance characteristics.

• 영어어문교육
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• 제18권1호
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• pp.1-22
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• 2012

This study explores the effects of phonological awareness instruction with phonetics on listening comprehension and speaking. For the test of measuring the improvement of listening comprehension, two nationwide listening comprehension tests were used for pre-test and post-test. To find out the improvement of speaking ability, students were required to take the Level-3 NEAT speaking tests. There was a notable correlation between phonological awareness instruction with phonetics and listening ability. Also a significant correlation between phonological awareness instruction with phonetics and speaking ability was found. The group with phonological awareness class with phonetics received higher scores in listening and speaking test than the group without phonological awareness class with phonetics in the post-test. This study implies that phonological awareness class with phonetics is helpful for the improvement of listening and speaking ability. With this research, we can also say that students' communicative competence increased.

• Transactions on Electrical and Electronic Materials
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• 제13권5호
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• pp.248-251
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• 2012

In order to develop a high voltage insulation material, epoxy/micro-silica composites (EMC) and epoxy/micro-silica/nano-silica composites (EMNC) with three different particle sizes in ${\mu}m$ and one particle size in nm were prepared and their tensile and flexural tests were carried out and the data was estimated by Weibull statistical analysis. The tensile strength of the neat epoxy was 82.8 MPa and those of the EMCs were larger than that of the neat epoxy, and they were much more advanced by the addition of 10 nm sized nano-silica to the EMCs. Flexural strength showed the same tendency of the tensile strength. As the micro-particle size decreased, tensile and flexural strength increased.

• 복식문화연구
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• 제9권4호
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• pp.629-638
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• 2001

This study was intended to identify the desired image and fabric preference of woman college student for apparel and the relationship between these variables. Data were collected by questionnaire distributed to 260 woman college students through August to September of 2000. After eliminating incomplete questionnaires, 236 were analyzed. The most desired image was neat, and the most preferred fabric was natural fiber textile in fiber contents and light and soft in fabric sensation. The avoided image was masculine, and the negative sensation was heaviness. As a result of factor analysis, 7 factors -cute, intellectual, animate, neat, mature, sporty, sexy- were determined in image. And 8 factors -soft, durable, flat, rigid, light, bulky, heavy, pliable- were determined in fabric sensation. These factors explained large percentage of variance respectively. Multidimensional scaling was employed to analyze the relationship between desired image and fabric preference. Two dimensions were accepted to interpret the relationship. One of the results showed the closeness among the natural fiber textile, lightness, durability and natural image. And the short distance among the blended textile, elasticity, warmness and sporty image was presented.