• 생명과학회지
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• 제25권11호
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• pp.1298-1303
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• 2015

후박나무(녹나무과)는 한국과 일본 등지에 서식하는 상록 교목으로 한국, 중국, 일본에서 부종, 복통, 복부 팽만 등의 질병 치료를 위해 오랫동안 사용되어오고 있다. 본 연구에서는 후박나무 껍질을 메탄올에 추출하고 메탄올 추출물을 헥산, 클로로포름, 부탄올에 순차적으로 분획하였다. 클로로포름 분획물로부터 2종의 화합물을 분리하였으며 분리된 화합물1과 2의 구조는 ¹H-, ¹³C-NMR과 참고 문헌 데이터에 의해 dibenzylbutane lignin 화합물인 macelignan (1)과 meso-dihydroguaiaretic acid (2)로 동정되었다. 분리된 화합물들의 tyrosinase 저해 활성을 측정한 결과, 화합물 2는 tyrosinase 저해 활성 중 monophenolase (IC₅₀ = 10.2 μM)에 대해 높은 저해활성을 나타내는 경쟁적 저해제였으며 효소에 결합하는 화합물 2의 저해 상수(K_i 값)는 4.8 μM였다. 따라서 meso-dihydroguaiaretic acid (2)는 멜라닌 생합성과 관련된 피부 질환 치료를 위한 잠재적 후보가 될 수 있을 것으로 판단된다.

• 소성∙가공
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• 제18권6호
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• pp.437-443
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• 2009

• 식품기술
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• 제7권2호
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• pp.103-110
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• 1994

• 식품기술
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• 제7권3호
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• pp.94-98
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• 1994

• 한국방사성폐기물학회:학술대회논문집
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• 한국방사성폐기물학회 2019년도 춘계학술논문요약집
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• pp.411-412
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• 2019

• Educational Technology International
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• 제21권2호
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• pp.217-247
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• 2020

Many developing countries consider ICT as a key enabler to improve their educational systems and teachers are viewed as change agents. This paper aims to present policy suggestions concerning how to foster teachers' ICT competencies in developing countries based on the outcomes of an ODA project case in Peru. This study was conducted through three stages: Literature survey, site visit, and policy suggestions. To draw relevant policy suggestions, we employed the framework of the 'macro-meso-micro' level of teacher professional development. The following policy suggestions are discussed: (a) macro level: to develop the national framework of teacher ICT competencies and competency-based teacher training, (b) meso-level: to promote teacher communities of practices and school-based research programs, and (c) micro-level: to redesign teacher professional development programs to help teachers better understand the complex relationships between content, pedagogy, and technology, beyond learning about basic ICT literacy skills. This study contributes to the understanding of how ODA projects can approach the issue of teacher ICT capacity building at multiple levels.

• 한국재료학회지
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• 제11권11호
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• pp.947-952
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• 2001

The meso-scale microstructure of the $Ni-Ni_3Al- Ni_3V$ system is crucial to obtain both high strength and high toughness. Its evolution may be predicted with the aid of computer simulation of the compositional separation for heat-treated alloys. In this study, computer simulations of the hypothetical A-B-C ternary system, which is similar to the $Ni-Ni_3Al- Ni_3V$ system in terms of phase equilibria, have been performed using the kinetic modeling. Simulated morphologies were changed with nominal compositions and model parameters. It was showed the current model was useful and the more realistic model was proposed.

• Journal of Mechanical Science and Technology
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• 제19권4호
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• pp.968-975
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• 2005

The shearing process for the sheet metal is normally used in the precision elements such as semi-conductor components. In these precision elements, the burr formation brings a bad effect on the system assembly and demands the additional de-burring process, so this imposes high cost on manufacturing. In this paper, we have developed the in-situ auto-aligning precision meso-punching system to investigate the burr formation mechanism and ultimately minimize burr. Firstly, we introduced the punch-die contact sensing method to align the punch and the die at initial state prior to the punching process. Secondly, by using the low-price semi-con­ductor laser, burr formed on the edges is measured intermittently during the punching process. We could, finally, make burr on the sheet metal uniformized and minimized by controlling of the precision X - Y table, $1\;{\mu}m$ resolution, and measuring burr height by semiconductor laser. Experimental results show the validity of our system for pursuing the burr-free punched elements.

• 한국정밀공학회지
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• 제18권3호
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• pp.18-22
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• 2001

• 한국광과학회:학술대회논문집
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• 한국광과학회 2006년도 정기총회 및 제13회 학술대회 논문 초록
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• pp.71-71
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• 2006