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- 저자 : Kuo-En Chang (검색결과 3 건)
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Shun-Tong Chen,Kuo-En Chang,Wei-Ping Huang,Hong-Ye Yang,Xiu-Mao Lee 한국정밀공학회 2012 International Journal of Precision Engineering and Vol. No.
This study presents the development of a cost-effective high-precision bench machine tool prototype for machining multi-level micro aspheric lighting-lens molds. To achieve high-precision over a long lifetime of micromachining, the bench machine tool is designed using a small C-shaped framework to strengthen static rigidity and vibration resistance. The primary structures of the machine tool are constructed with tempered nodular graphite cast iron to obtain a high damping coefficient and high inherent resonant frequency. A multi-level aspheric curve generator is designed according to the multi-level aspheric curve equation to easily create an aspheric curve and then rotated into an aspheric surface form with a symmetrical optical axis. The verifications of the designed bench machine tool’s functions were conducted by machining the micro aspheric lighting-lens molds using highspeed micro milling. Experimental results demonstrate that form accuracy and surface roughness for the micro aspheric lightinglens mold of Rt 2.937 μm and Ra equal to 0.032 μm respectively could be simultaneously achieved. The developed cost-effective bench machine tool can supply high-quality and fast machining in the fabrication of micro optoelectronic molds such as those used for micro aspheric lighting-lenses.
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Cooperative Learning in Small EFL Early Reading Groups
( Yu Ju Lan ),( Kuo En Chang ),( Yao Ting Sung ) 범태평양응용언어학회 2005 범태평양응용언어학회지 Vol.9 No.2
The purpose of this study is to explore the interactive behaviors and intra-group discourse in a cooperative reading group when students were asked to do meaning-based reading tasks with their group mates cooperatively. The subjects were 52 third graders from an elementary school of Taipei, Taiwan. For ten weeks, both video and audio data were collected. Based on the finding of qualitative data analysis, we found four main types of group interactive behavior which we called Ardent, Be-forced, Supervisory, and Wait-on. According to the intra-group discourse, we also found that peer-assisted learning existed in cooperative reading groups and most of the peer discourse provided essential scaffolding, modeling, and direct instruction dialogs that help children with lower reading abilities do meaning-based reading.
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Wu Szu-Hsien,Yu Jin-Huei,Liao Yu-Ting,Liu Kuo-Hao,Chiang En-Rung,Chang Ming-Chau,Wang Jung-pan 한국조직공학과 재생의학회 2022 조직공학과 재생의학 Vol.19 No.3
BACKGROUND: Infant adipose-derived mesenchymal stem cells (ADSCs) collected from excised polydactyly fat tissue, which was surgical waste, could be cultured and expanded in vitro in this study. In addition, the collecting process would not cause pain in the host. In this study, the proliferation, reduction of senescence, anti-oxidative ability, and differentiation potential in the infant ADSCs were compared with those in the adult ADSCs harvested from thigh liposuction to determine the availability of infant ADSCs. METHODS: Proliferation was determined by detecting the fold changes in cell numbers and doubling time periods. Senescence was analyzed by investigating the age-related gene expression levels and the replicative stress. The superoxide dismutase (SOD) gene expression, adipogenic, neurogenic, osteogenic, and tenogenic differentiation were compared by RTqPCR. The chondrogenic differentiation efficiency was also determined using RT-qPCR and immunohistochemical staining. RESULTS: The proliferation, SOD (SOD1, SOD2 and SOD3) gene expression, the stemness-related gene (c-MYC) and telomerase reverse transcriptase of the infant ADSCs at early passages were enhanced compared with those of the adults’. Cellular senescence related genes, including p16, p21 and p53, and replicative stress were reduced in the infant ADSCs. The adipogenic genes (PPARc and LPL) and neurogenic genes (MAP2 and NEFH) of the infant ADSC differentiated cells were significantly higher than those of the adults’ while the expression of the osteogenic genes (OCN and RUNX) and tenogenic genes (TNC and COL3A1) of both demonstrated opposite results. The chondrogenic markers (SOX9, COL2 and COL10) were enhanced in the infant ADSC differentiated chondrogenic pellets, and the expression levels of SODs were decreased during the differentiation process. CONCLUSION: Cultured infant ADSCs demonstrate less cellular senescence and replicative stress, higher proliferation rates, better antioxidant defense activity, and higher potential of chondrogenic, adipogenic and neurogenic differentiation.
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