• 한국CDE학회논문집
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• 제20권3호
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• pp.312-319
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• 2015

The grinding and furbishing process as the finishing process for molds include the works such as the grinding, buffing, lapping and polishing among others. A finishing tool unit is applied to this finishing process for the burr, lapping, polishing and others of molds. A finishing tool unit can carry out the flexible machining, depending on the machining allowance for objects to be cut on the basis of the instrumental driving mechanism which enables the up, down, left and right floating, which is applied in link with the dedicated cutters and robot machining systems. This study selected the shape to increase the rotatory force of an impeller when air is discharged during the driving of a finishing tool unit, and reflected it to the impeller designing. In addition, the study analyzed each flow velocity and pressure distribution per air pressurization value and finally analyzed the rotating torque to suggest the optimal conditions in designing impellers.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2005년도 춘계학술대회 논문집
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• pp.48-53
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• 2005

The world, coming into the 21st century, is preparing a new revolution called a knowledge-based society after the industrial society. The interest of the world is concentrated on information technology, nano-technology and biotechnology. In particular, the nano-technology of which study was originally started from an alternative for overcoming semiconductor micro-technology. It can be applied to most industry subject such as electronics, information and communication, machinery, chemistry, bioengineering, energy, etc. They are emerging into the technology that can change civilization of human beings. Specially, ultra precision machining is quickly applied to nano-technology in the field of machinery. Lately, with rapid development of electronics industry and optic industry, there are needs for super precision finishing of various core parts required in such related apparatuses. This paper handles stability of a super precision micro cutting machine that is a core unit of such a super precision finisher, and analyzes the results depending on the hinge type and material change, using FEM analysis. By reviewing the stability, it is possible to achieve the effect of basic data collection for unit control and to reduce trials and errors in unit design and manufacturing.

• 한국수학교육학회지시리즈A:수학교육
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• 제48권1호
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• pp.21-32
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• 2009

The purpose of this study is to diagnose the current states and the problems of student assessment of Elementary School Mathematics. For that purpose, this study conducted a survey and had the individual interviews. The surrey items consisted of the six main parts: questions about the development of assessment tools, the method to assess, the grading, the special supplementary courses, the opening of learning effect, and the follow-up guidances. The results of this study are as the follow First, elementary teachers depended heavily on internet sites for developing assessment problems. Second, elementary teachers made use of a performance assessment, a unit assessment, and a term examination at ordinary times. Third, unit assessment was largely referred for grading by elementary teachers. Fourth, in selecting the students for the special supplementary courses, both criterion-referenced assessment and norm-referenced assessment were considered. After finishing the special supplementary courses, additional tests were usually taken. Fifth, elementary teachers took a negative attitude in opening of learning effect. specialty opening of test paper to parents of students was done under 30%. Sixth, fellow-up guidances were the most through the classroom guidances. but consulting with parents of students was not frequently conducted by teachers.

• 터널과지하공간
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• 제8권4호
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• pp.332-341
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• 1998

석판재의 모서리 가공작업은 많은 경우 자동화가 이루어지고 있지만 제품의 형태 가 복잡해지면 여전히 수작업에 의해 연마가 이루어지고 있다. 본 논문을 성형공구의 제작 에 앞서 성형공구의 특성과 장비의 운영요소들의 변화에 따른 연마절삭성능을 파악하기 위 한 기본시험이 수행결과를 나타내는 것이다. 장비의 운영요소는 헤드의 회전속도 및 이송속 도, 가압하중, 급수율, 절삭방향과 이송방향이 포함된다. 실험결과는 연마절삭성능 즉 공구 마모 무게에 대한 판재의 절삭량으로 표시하였고, 각 운영요소들 마다의 적정 운영수준이 제시되어 있다. 또한 연마재 투입략의 변화에 대한 마모시험에서는 마모도는 연마재의 증가 에 따라 증가하지만 어느 이상의 양에서는 오히려 감소하고 있다.