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Effects of Reading Environments on L2 Learners’ Strategic Behaviors toward Unknown Words
Sang-Kyo Lee(이상교) 한국중원언어학회 2011 언어학연구 Vol.0 No.19
This study explores effects of reading environments, computer-based and print-based texts, on L2 learners’ strategic behaviors in coping with unknown words while reading texts in English. The results show that reading environment did appear to affect learners’ strategies for coping with unknown words, but the effect was not substantial. The learners employed more strategies in computer-based texts(CBT) than in print-based texts (PBT). In terms of the learners’ levels of vocabulary knowledge, the advanced group is influenced by the effect of reading environment more than the other two groups-intermediate and low. Although the effect of reading environment is almost negligible in the low group, the frequency of strategies employed by this group is far greater than the other two groups.
박막성형 기술 및 MEMS 공정을 이용한 자기변형 위치변환기
이흥식(Heung-Shik Lee),조종두(Chongdu Cho),이상교(Sang-kyo Lee) 대한기계학회 2007 대한기계학회 춘추학술대회 Vol.2007 No.5
This paper presents a magnetostrictive transpositioner and its fabrication process. To get a transposition movement without shifting or twisting, it is designed as an array type. To fabricate the suggested design, micromachining and selective DC magnetron sputtering processes are combined. TbDyFe film is sputterdeposited on the back side of the bulk micromachined transpositioner, with the condition as: Ar gas pressure below 1.2×10?? torr, DC input power of 180W and heating temperature of up to 250℃ for the wireless control of each array component. After the sputter process, magnetization and magnetostriction of each sample are measured. X-ray diffraction studies are also carried out to determine the film structure and thickness of the sputtered film. For the operation, each component of the actuator has same length and out-of-plane motion. Each component is actuated by externally applied magnetic fields up to 0.5T and motion of the device made upward movement. As a result, deflections of the device due to the movement for the external magnetic fields are observed.
방혜진(Hye-jin Bang),이상교(Sang-kyo Lee),조종두(Chongdu Cho),조재웅(Jae-ung Cho),최해규(Hae-kyu Choi) 대한기계학회 2012 대한기계학회 춘추학술대회 Vol.2012 No.11
Aluminum foam has developed in many commercial fields, especially transport machines division as a kind of porous metal. In this paper, Aluminum foam with the initial crack and closed cell form is used to take the axial load-time graph. It is fabricated with adhesively bonded DCB (Double Cantilever Beam) form and accordance with BS (British Standard) and ISO international standard. Using 10 kN Landmarks of MTS Corporation, 15 ㎜/min velocity of mode I shape is applied to aluminum foam specimen with displacement control method. And ABAQUS 6.10 is used to model and analyze the same model as a three dimension with same condition of experiment. Based on the result of axial load-displacement graph of experiment and image of that included of crack length depended on the time, energy release rate will be calculated and then the model is analyzed with this fracture energy condition. As a result, it is shown that different force aspect according to the displacement value and there is not big deformation in aluminum foam while Double Cantilever Beam get the force due to aluminum foam has bigger density and modulus than adhesive. Also, the similar maximum value is calculated using finite element method of cohesive element comparing with experiment.
원지혜(Ji-hye Won),이상교(Sang-kyo Lee),이흥식(Heung-shik Lee),최은영(Eun-young Choi),조종두(Chongdu Cho),서형주(Hyoung-joo Seo),김성담(Seong-dam Kim),세오히로유키(Seo Hiroyuki),김영길(Young-gil Kim) 한국자동차공학회 2009 한국자동차공학회 학술대회 및 전시회 Vol.2009 No.11
In this study, wire, bundle and ass’y level of the wire harness system are investigated for the fatigue life prediction using both finite element method (FEM) and experimental analysis. To obtain stress-life (S-N) histories of the componential wires of the system, wires are prepared and applied repeated bending motion using developed fatigue life equipment. Equivalent model of the wire from rule of mixture theory is used for the simplification of the analysis. Contact conditions among the wires, taping conditions, optimized composition of wires, effects of the number of wires in the bundle are derived through the bundle level test and bundle numerical analysis. Wire and bundle level results are adopted for the ass’y level analysis. For the ass’y level analysis, real wire harness system including bundle and grommet is numerically modeled and applied contact condition between wire and grommet with real opening motion. As a result, we was able to shorten development time by developing the simulation methodology for wire harness reliability using the FEM in the early stages of wire harness development..
접착제로 접합된 이중외팔보 알루미늄폼의 파괴 거동에 관한 연구
방혜진(Hye-jin Bang),이상교(Sang-kyo Lee),조종두(Chongdu Cho),조재웅(Jae-ung Cho),최해규(Hae-kyu Choi) 대한기계학회 2014 大韓機械學會論文集A Vol.38 No.5
본 논문에서는 초기균열을 갖고 있는 폐포형 구조, 발포알루미늄의 축방향 기계적 거동을 실험 및 유한요소해석으로 연구하였다. 재료시험에서 MTS 사의 10kN Landmarks 를 사용하여, 모드 I 형상의 15mm/min 의 하중속도로 변위를 제어하였다. 또한 유한요소해석 범용프로그램인 ABAQUS 6.10 으로 3 차원 형상의 실험과 동일한 조건으로 모델을 구성하여 해석을 수행하였다. 실험의 축방향 변위-하중 그래프와 시간에 대한 균열 길이를 기반으로 에너지 해방률을 계산하였으며, 이 값을 해석에서 파손 에너지조건으로 사용하였다. 결과적으로 변위 값에 따른 하중 거동을 확인할 수 있었으며, 발포알루미늄이 접착제에 비해 상대적으로 큰 밀도와 탄성계수를 가지므로 발포알루미늄의 변형이 상대적으로 작다는 것을 확인할 수 있었다. In this study, closed-cell aluminum foam with an initial crack was investigated to produce an axial load-time graph. Using the 10-kN Landmarks of MTS Corporation, a 15-mm/min velocity of mode I shape was applied to the aluminum foam specimen using the displacement control method. ABAQUS 6.10 simulation was used to model and analyze the identical model in three dimensions under conditions identical to those of the experiment. The energy release rate was calculated on the basis of an axial load-displacement graph obtained from the experiment and a transient image of the crack length, and then an FE model was analyzed on the basis of this fracture energy condition. The relation between load and displacement was discussed; it was found that the aluminum foam deformed somewhat less than the adhesive layer owing to the difference in elastic modulus.
정공 주입 물질 두께 변화에 따른 유기 발광 다이오우드 효율 향상
김원종(Weon-Jong Kim),이영환(Young-Hwan Lee),차기호(Ki-Ho Cha),이상교(Sang-Kyo Lee),김태완(Tae-Wan Kim),홍진웅(Jin-Woong Hong) 대한전기학회 2006 대한전기학회 학술대회 논문집 Vol.2006 No.7
In the structure of ITO/HIL/Alq₃/Al device, we investigated an efficiency improvement of the Organic Light-Emitting Diodes depending on thickness variation of hole-injection layer. Using the thermal evaporation in a base vacuum 5×10?? [Torr], we have measured efficiency after the Alq₃ was evaporated to 100[㎚] as a deposition rate 1.5 [A/s]. In optimal condition, when PTFE thickness increased from 0 to 3.0[㎚], we have obtained that an optimal thickness of PTFE was 2.5[㎚]. And using the PTFE, luminance efficiency and external quantum efficiency of the device were improved by 12.8 times and 11.1 times, respectively.