• Proceedings of the KSPS conference
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• 2007.05a
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• pp.99-101
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• 2007

This study analyzes Korean middle school students' pronunciation errors of stop-liquid sequences in English. The results showed two typical errors: the insertion of a vowel between a stop and a liquid and the substitution of a liquid with a flap or vice versa. Those pronunciation errors seem to occur since English and Korean have different syllable structures and different types of liquids. A teaching material, which emphasizes no vowel insertion for a proper pronunciation of the consonant clusters, was designed to reduce Korean students' pronunciation errors. Errors were reduced substantially after a 50-minute class with the newly designed material.

• Proceedings of the KSPS conference
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• 2007.05a
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• pp.167-169
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• 2007

This study analyzes Korean students' pronunciation errors in stop-nasal sequences in English. For the study, 23 English words of stop-nasal sequences were pronounced by 4 natives and 21 Korean students. The results showed two kinds of pronunciation errors: the insertion of a vowel and the nasal assimilation between stops and nasals. A teaching material was designed based on the errors. After a 60-minute class with the material they were asked to pronounce the same words in another session. There was a substantial improvement in the error correction.

• Research in Mathematical Education
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• v.9 no.3 s.23
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• pp.257-267
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• 2005

When notions of numbers are expanded from natural number to complex number, a similar mathematical phenomenon can be observed in each number. As a case study, to complex number, the phenomenon is investigated carefully and teaching materials are created. Then complex number is expressed with matrices and is geometrically treated, so a new number which is an extension of complex number is discovered. Thus, teaching material regarding to complex number and matrices is made for students of ordinary level. Moreover, for talented students, material about an extension of complex number can be added to the previous one.

• Journal of Gifted/Talented Education
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• v.14 no.4
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• pp.113-123
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• 2004

The concern with scientific mode1s has been growing in science education, and schematic models are frequently used to teach science concepts in secondary schools. The aim of this study is to investigate how well the scientifically gifted students understand scientific concepts through activities of modifying scientific models which we developed. Thirty 8th-grade students participated in the study, 15 in a control group and 15 in an experimental group. For the students in the experimental group, teaching material with activities of modifying models, while for the students in the control group, the teaching material with traditional activities such as explanation, problem solving, and reading. The teaching contents in physics for both groups were linear momentum. We used multiple-choice test and essay-type test to evaluate students' achievements after lessons, and then compared their achievements of both groups. Through the research, we could find a clue that model-modifying activities are helpful for the gifted students to enhance their understanding of physics concepts, although the statistics does not show meaningful difference between experimental and control groups.

• Journal of The Korean Association For Science Education
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• v.17 no.4
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• pp.425-433
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• 1997

The purpose of this study was to examine for middle school science textbooks published by the sixth curriculum to analyze STS material, activity, and space devoted to STS. Because most teachers and students are dependent upon textbooks in teaching and learning, analyzing science textbooks will give basic information to ascertain the extent to which the current school science incorporate STS themes. Results indicated that lots of STS topics in the middle school science text books are related to applications of science. They also revealed that about 3% of the narrative space is devoted to STS topics, with a range of 0.7% to 5.2%. The coverage of STS topics increases as grade level increases.

• Elastomers and Composites
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• v.51 no.1
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• pp.43-48
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• 2016

Multi-Surface (MS) treatment is a new technique of surface treatment to reduce the static friction factor on the surface of rubber. MS treatments include 4 methods which names are MS-V (UV-irradiation on the rubber surface), MS-M (doing the chemical reaction with double bond of rubber), MS-Q (dilution of rubber surface by silicone surfactant), and MS-P (coating and heating of rubber surface). The experiment and test of every MS-treatment had been carried out using acrylonitrile-butadiene rubber (NBR), ethylene-propylene-diene rubber (EPDM), and chlorosulphonated rubber (CSM) as rubber materials. It had introduced the steps of every MS-treatment process and the result of the properties test. From the research, it was found that the best method was MS-V treatment because it suited all the samples and the effect was obviously.

• The Journal of Korean Association of Computer Education
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• v.8 no.2
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• pp.53-60
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• 2005

The teaching plan is an important material for teaching and learning, and it goes through many hardships to make out it. Although these materials have been shared through web and referenced for making their teaching plan by other teachers, it has been little utilized yet in learning. In this paper, we proposed a strategy for utilizing the teaching plan as a useful material in learning and had developed the web-based system for managing and utilizing the teaching plan based on the strategy.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.185-185
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• 2008

This paper describes the broadband SDC (Single-ended to Differential Converter) for Digital Video Broadcasting-Satellite $2^{nd}$ edition (DVB-S2) receiver tuner IC. It is fabricated by using $0.18{\mu}m$ CMOS process. In order to obtain high linearity and low phase mismatch, the broadband SDC (Single-ended to Differential Converter) is designed with current mirror structure and cross-coupled capacitor and current source binding differential structure at VDD. The simulation result of SDC shows IIP3 of 11.9 dBm and IIP2 of 38 dBm. It consumes 5mA current with 2.7V supply voltage.

• Structural Engineering and Mechanics
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• v.57 no.2
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• pp.369-387
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• 2016

In this work, random homogenization analysis for the effective thermal properties of a three-dimensional composite material with unidirectional fibers is presented by combining the equivalent inclusion method with Random Factor Method (RFM). The randomness of the micro-structural morphology and constituent material properties as well as the correlation among these random parameters are completely accounted for, and stochastic effective thermal properties as thermal expansion coefficients as well as their correlation are then sought. Results from the RFM and the Monte-Carlo Method (MCM) are compared. The impact of randomness and correlation of the micro-structural parameters on the random homogenized results is revealed by two methods simultaneously, and some important conclusions are obtained.

• Journal of the Semiconductor & Display Technology
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• v.17 no.1
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• pp.1-5
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• 2018

Wood Polymer Composites(WPC) have attracted significant attention because of ecological and environmental concerns. However, the structure of Wood Flour containing many hydroxyl groups(-OH) reduces the interface adhesion to Phenol-formaldehyde(PF) and it decreases the mechanical properties of the PF/Wood Flour Composites. The present work involves the modification of Wood Flour using silanes reinforced with Phenol-formaldehyde to enhance the mechanical properties of the composites. The spectroscopic properties of the composites were analyzed using FT-IR, XPS(X-ray Photoelectron Spectroscopy) and the mechanical properties i.e., tensile strength, flexural strength and impact strength were studied. We confirmed the modification effect of silanes by spectroscopic analysis, and the mechanical properties of the composites using wood flour modified by silanes were significantly improved.