• 비교문화연구
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• 제27권
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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.

• 한국전기전자재료학회논문지
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• 제24권5호
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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.

• 한국진공학회지
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• 제22권6호
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• pp.313-320
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• 2013

실리콘(Silicon, Si) 기판과 $Al_{0.3}Ga_{0.7}As$/GaAs 다중 양자 우물(multiple quantum wells, MQWs) 간의 격자 부정합 해소를 위해 $AlAs_xSb_{1-x}$ 층이 단계 성분 변화 완충층(step-graded buffer, SGB)으로 이용되었다. $AlAs_xSb_{1-x}$ 층 상에 형성된 GaAs 층의 RMS 표면 거칠기(root-mean-square surface roughness)는 $10{\times}10{\mu}m$ 원자 힘 현미경(atomic force microscope, AFM) 이미지 상에서 약 1.7 nm로 측정되었다. $AlAs_xSb_{1-x}$/Si 기판 상에 AlAs/GaAs 단주기 초격자(short period superlattice, SPS)를 이용한 $Al_{0.3}Ga_{0.7}As$/GaAs MQWs이 형성되었다. $Al_{0.3}Ga_{0.7}As$/GaAs MQW 구조는 약 10 켈빈(Kalvin, K)에서 813 nm 부근의 매우 약한 포토루미네선스(photoluminescence, PL) 피크를 보였고, $Al_{0.3}Ga_{0.7}As$/GaAs MQW 구조의 RMS 표면 거칠기는 약 42.9 nm로 측정되었다. 전자 투과 현미경(transmission electron microscope, TEM) 단면 이미지 상에서 AlAs/GaAs SPS 로부터 $Al_{0.3}Ga_{0.7}As$/GaAs MQWs까지 격자 결함들(defects)이 관찰되었고, 이는 격자 결함들이 $Al_{0.3}Ga_{0.7}As$/GaAs MQW 구조의 표면 거칠기와 광 특성에 영향을 주었음을 보여준다.