• Cross-Cultural Studies
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• v.27
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• pp.497-523
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• 2012

Characteristics of the Listening and Pronunciation of Korean Obstruents of Chinese Learners -Based on the Phonetic Experiments Using Kalvin and Praat- This study aims at investigating the characteristics of confrontation in three ways, lax/ fortis/ aspirated consonants, in Korean obstruents through experimental phonetic analysis for the Chinese Korean language learners. On one hand, as a result of comparing Korean and Chinese obstruent systems, there is no big difference regarding the articulatory location. On the other hand, in regards to the articulatory method there is a difference. In a Korean obstruent system, the confrontation presented in three ways by the strength of aspiration. On the contrary, the Chinese obstruent system showed confrontation in two ways by the existence of aspiration. To examine the difficulty of the learners caused by the above-mentioned reason objectively, this paper studied the relationship between input and output of sound through the experimental phonetic analysis such as Kalvin and Praat. To research the input of sound, the listening ability of the learners was examined by 'Choosing Consonant' among the Menu of Kalvin. As a result of that experiment, many errors were shown. They recognized the fortis as lax in the area of affricates and plosives. In the area of fricatives, they recognized affricatives as fricatives. To investigate the output of sound, the section of aspiration and the section of friction of a plosive, an affricate and a fricative in Praat, were expressed numerically. The learners' VOT of lax and affricate represented that lax was pronounced close to the fortis, and the VOT of fricatives was not shown the section of aspiration and friction clearly, and also the result showed that they pronounced a fricative like affricative-aspirated one. The result shows that the learners' pronunciation is related to the listening ability. The consequence is caused by the characteristics of the difference between Korean obstruents and Chinese ones. If the training pronunciation is conducted based on above result, it would be a better methodology in teaching Korean.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.24 no.5
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• pp.351-354
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• 2011

This paper was carried about thermal analysis for high efficiency point contact solar cell. Therefore, we carried about 2-D device and process simulator according to design and process parameters. As a result of simulations, power transfer efficiency have decreased more increasing temperature. Especially, power transfer efficiency of room temperature have been showed 25%. The other hand, power transfer efficiency of 350 K kalvin temperature have been showed 20%. Therefore, we will considered design with thermal dissipation of device.

• Journal of the Korean Vacuum Society
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• v.22 no.6
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• pp.313-320
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• 2013

The $AlAs_xSb_{1-x}$ step-graded buffer (SGB) layer was grown on the Silicon (Si) substrate to overcome lattice mismatch between Si substrate and $Al_{0.3}Ga_{0.7}As$/GaAs multiple quantum wells (MQWs). The value of root-mean-square (RMS) surface roughness for 5 nm-thick GaAs grown on $AlAs_xSb_{1-x}$ step-graded buffer layer was ~1.7 nm. $Al_{0.3}Ga_{0.7}As$/GaAs MQWs with AlAs/GaAs short period superlattice (SPS) were formed on the $AlAs_xSb_{1-x}$/Si substrate. Photoluminescence (PL) peak at 10 K for the $Al_{0.3}Ga_{0.7}As$/GaAs MQW structure showed relatively low intensity at ~813 nm. The RMS surface roughness of the $Al_{0.3}Ga_{0.7}As$/GaAs MQW structure was ~42.9 nm. The crystal defects were observed on the cross-sectional transmission electron microscope (TEM) images of the $Al_{0.3}Ga_{0.7}As$/GaAs MQW structure. The decrease of PL intensity and increase of RMS surface roughness would be due to the formation of the crystal defects.