• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.10a
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• pp.137-140
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• 1997

In general, stereolithography parts is not suitable for master pattern. Because of its bad surface roughness. Therefore, To reduce roughness it requires post-process that is depending on user skill and takes long time to do. This study aims to develop an expert system which can select an optimal build orientation, reduce roughness and shorten post-processing time. Genetic Algorithm was introduced for optimization. A simplified computation model was developed for real-time response. For accurate roughness estimation, mterpolation of experimental data was implemented.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.46-49
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• 2003

Microsystem technology (MST) which originated from semiconductor processes has been widely spreaded into tile other industry such as sensors, micro fluidics and displays. The MST, however. has been troubled in spreading with its high cost and material limitations. So, in this paper, new process for micromolding technology using silicone rubber mold was introduced. Silicone rubber mold, which was fabricated by vacuum casting. can be transferred a master pattern to a final product with the same shape but different materials. In order to verify the possibility of application of silicone rubber mold to the MST, its transferability was evaluated. and then it applied to the fabrications of polishing pad and PDP barrier ribs.

• Education of Primary School Mathematics
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• v.8 no.1
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• pp.1-11
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• 2004

Whole number concept is an important part of mathematics learning. Elementary school students should understand and master whole number concept. Models can help students learn whole number concepts. Realistic Mathematics Education in Netherlands had investigated and developed three different structural models: line model, group model, combination model. These models are related whole number concepts and structures closely and compatible. The purpose of this study is to investigate models related with whole numbers in 7th elementary textbooks. As a result of analyses, we found out some pattern and several problems. On the foundation of the analyses, we discussed the better ways of using models in teaching whole number and the research issues concerning these.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.624-627
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• 2003

Microcontact printing (uCP) of alkanethiols on gold was the first representative of soft-lithography processes. This is an attempt to enhance the accuracy of classical to a precision comparable with optical lithography, creating a low-cost, large-area, and high-resolution patterning process. Microcontact printing relies on replication of a pattered PDMS stamp from a master to form an elastic stamp that can be inked with a SAM solution(monolayer -forming ink) using either immersion inking or contact inking. The inked PDMS stamp is then used to print a pattern that selectively protects the gold substrate during the subsequent etch.

• Journal of the Korean Society for Precision Engineering
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• v.30 no.2
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• pp.236-240
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• 2013

In this presentation, we propose a fabrication method of PDMS stencil to apply into a localized culture of NIH/3T3 cells. PDMS stencil was fabricated by nitrogen gas blowing and soft lithography from preparing SU-8 master mold by photolithography. PDMS stencil pattern was production of the circle size 20 to $500{\mu}m$. In the culture test of PDMS stencil, a stencil was placed on a glass disk. The NIH/3T3 cells were successfully cultured into micropatterns by using the PDMS stencil. The results showed that cells could be cultured into micropatterns with precisely controlled manner at any shapes and specific size for bioscience study and bioengineering applications.

• Proceedings of the Korean Nuclear Society Conference
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• 1995.10a
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• pp.475-479
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• 1995

During the hypothetical loss of coolant accident in the nuclear power plant the emergency core cooling water could not penetrate to the reactor core when the steam flow rate from the reactor core exceeds CCFL (Countercurrent flow limitation). The CCFL generated by earlier investigators are developed under the steady gas flow. However the flow instability in the reactor loop could generate oscillatory steam flow, hence their applicability under oscillating flow should be investigated. In this work, an experimental investigation of countercurrent flow in the vertical flow channel has been conducted under oscillatory gas flow. Pulsation of gas under oscillatory flow disturbs the flow pattern significantly and prevents flooding (CCFL) when its minimum value is less than the threshold gas flow rate value.

• Journal of the Korean Society for Library and Information Science
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• v.23
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• pp.107-125
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• 1992

The purpose of this study is to investigate the research trend of information user studies. The following findings are made. The literature on information user studies during 1980-1990 reveals 120 titles. The faculty members of university tend to publish their results in scientific journals and university publication while non-faculty members are more likely to represent their research papers in unpublished master thesis and bulletin. Subject distribution of research were classified into ten: user studies, material use studies, information needs and uses, user education, library use pattern, citation analysis, journal use, catalog use, information system, non-use study. Survey research, literature research, survey reserch and literature research use jointly, experimental research and citation analysis were employed for information user studies.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.27 no.8
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• pp.1380-1387
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• 2003

Microsystem technology (MST) which originated from semiconductor processes has been widely spreaded into the other industry such as sensors, micro fluidics and displays. The MST, however, has been troubled in spreading with its high cost and material limitations. So, in this paper, new process for micromolding technology using silicone rubber mold was introduced. Silicone rubber mold, which was fabricated by vacuum casting, can be transferred a master pattern to a final product with the same shape but different materials. In order to verify the possibility of application of silicone rubber mold to the MST, its transferability was evaluated, and then it applied to the fabrications of polishing pad and PDP barrier ribs.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.493-494
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• 2006

SU-8 can be implemented as a mask for micro Abrasive Jet Machining (micro-AJM) process [1]. In this paper, we will evaluate the quality of micro grooving result on glass substrate by micro-AJM process which using SU-8 as a mask. It was evaluated on width and edge profile of the micro grooving. The result was having distortion compare with the master film used to pattern the SU-8 mask. The value of distortion with other properties which came along with it, such as depth and surface roughness, can be optimized in order to fabricate micro-channel for micro-fluidic application.

• Journal of the Korean Society for Library and Information Science
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• v.41 no.4
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• pp.201-215
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• 2007

This study is to examine the research trends of the young people in Korea through an analysis of master's and doctor's dissertations. And to analyze the citations and documents in various aspects. such as; year, object, pattern, bibliotherapy program etc. The study is to present basic data for researcher and to indicate the direction of the study in the future.