• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2015.05a
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• pp.34-34
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• 2015

본 연구에서는 AZ31 마그네슘 합금의 내식성을 향상시키기 위하여 플라즈마 전해산화(PEO, plasma electrolytic oxidation)법을 이용하여 다양한 용액에서 양극 및 음극 펄스전류를 인가하여 형성하였다. 형성된 PEO피막의 두께는 용액 중 음이온의 종류에 가장 크게 의존하였으며, PEO 피막의 표면거칠기는 피막의 두께가 두꺼울수록 더 커지는 결과를 얻었다. PEO피막의 경도는 규산이온이 포함된 용액에서 형성된 피막이 가장 높게 나타났으며, 알루미나 입자들과 같이 단단한 입자들을 용액 중에 포함시킬 경우 피막 내부에 함침되어 피막의 경도를 향상 시킬 수 있었다.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2012.05a
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• pp.307-307
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• 2012

마그네슘합금은 넓은 분야에서 사용되고 있지만 높은 산화성과 화학반응성 때문에 표면처리를 하지 않고서는 사용 할 수 없다. 따라서 본 과제에서는 개발 중인 신 마그네슘 합금소재의 부식 및 피막특성을 관찰하기 위해 염수분무시험, 염수침지, 분극 시험 및 도장밀착성 내식성 시험을 시행하였다. 이 결과는 새로 개발되는 신 마그네슘 합금 성분 및 함량 결정의 기초 데이터가 될 것이다.

• Journal of the Korean Society for Library and Information Science
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• v.56 no.2
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• pp.133-155
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• 2022

The purpose of this study was to develop the indicatives for the analysis of the effects of Gyeonggi-do Book Sharing Project on pre-schoolers of supporter' reading care and thereby, suggest some data useful to the establishment of a reading culture promotion policy in Gyeonggi-do. Preceding studies and cases were reviewed to analyze the effects of the book-sharing project on pre-schoolers of supporter' reading care and thereby, develop some measurement indicatives, and thus, the indicatives were verified by professionals using the Delphi technique. Then, supporter of 3~5 year-old pre-schoolers were sampled from 7 cities and counties in Gyeonggi-do (Pocheon-si, Yangpyeong-gun, Yeoju-si, Dongducheon-si, Gapyeong-gun, Yeoncheon-gun and Yangju-si) to be divided into control and test groups and thereby, their reading care effect indicatives were compared before and after the test. The theoretical background is theory of family literacy, emergent literacy and parenting efficacy. As a result of developing the indicatives for analysis of pre-schoolers of supporter's reading care effects and comparing them for the sample pre-schoolers of supporter, before and after the test, the book-sharing project was found effective in improving reading care. The most difficult problem in pre-schoolers' earlier reading education involves acquisition of reading habit. So, it is deemed necessary to operate a regular book sharing project involving public organization and homes. As a result of developing the indicatives and analyzing the effects of the book-sharing project, it was confirmed that the project would serve to improve pre-schoolers of support's reading care and therefore, this study seems to provide some ground for the operation of a sustainable book-sharing project to narrow the education divide and promote a book reading culture in Gyeonggi-do.

• Korean Journal of Child Studies
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• v.22 no.2
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• pp.301-313
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• 2001

This study explored the linkage between literacy and writing with a computer in three-to five-year-old children. The 57 subjects were closely observed as they produced written language forms using the word processing program, Araeha Hangul. Stages of writing with a computer were developed to assess the children's computer-writing. While writing with a computer, children invented letters, words, and sentences in an experimental and playful way. Children's writing with computer improved with age. There was a positive correlation between writing with a computer and writing with a pencil. In this way, computer writing was found to be part of written language development.

• Journal of Ocean Engineering and Technology
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• v.23 no.6
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• pp.87-92
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• 2009

The effect of aging on the precipitation of the $\sigma$ phase and the corrosion resistance in tungsten substituted super duplex stainless steels was investigated. The volume fraction of the $\sigma$ phase and the current density increased with aging at temperatures up to $750^{\circ}C$ and then decreased. With an increase in aging time, the volume fraction of the $\sigma$ phase and the current density also increased. The $\sigma$ phase hardly influenced the corrosion resistance. With the substitution of tungsten for molybdenum in super duplex stainless steel, the volume fraction of the $\sigma$ phase and the current density decreased remarkably.

• Journal of Power System Engineering
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• v.10 no.3
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• pp.51-57
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• 2006

The effect of grain size on corrosion resistance and high temperature oxidation behavior was studied in 22Cr-15Ni-5W super austenitic stainless steels for desulfurization equipment as a heat power station. In the high temperature oxidation test, oxidation rate was increased as the temperature increased from $600^{\circ}C\;to\;800^{\circ}C$. In vapor, oxidation rate was faster than that in air. Because the vapor was inhibited nucleation of $Cr_2O_3$ film. And the high temperature oxidation resistance at $600^{\circ}C{\sim}800^{\circ}C$ was excellent from all specimens and specimen of the smallest grain size was the most excellent. Because increasing of diffusion course through the grain-boundary was promoted nucleation and growth of $Cr_2O_3$ film. In the test temperature at $600^{\circ}C{\sim}800^{\circ}C$, Cr rich round particle oxide was formed in air, whereas Fe rich needle type oxide was developed in vapor.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2018.06a
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• pp.66.1-66.1
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• 2018

최근 자동차 배기가스 규제 및 전기자동차, 무인항공기 개발 등의 경량 소재에 대한 필요성이 지속적으로 증가하고 있다. 마그네슘 및 마그네슘 합금은 구조용 금속 소재 중 가장 밀도가 낮은 금속으로서 자동차, 항공, 기계 부품류 및 주방용품이나 전자제품 케이스류 등 다양한 산업분야에서 활용성이 크게 증가하고 있다. 하지만 마그네슘 합금은 화학적 반응성이 매우 크고 표면에 존재하는 피막의 치밀성과 화학적 안정성이 낮아서 쉽게 부식되는 단점이 있다. 따라서 내식성 향상을 위한 표면처리 기술 개발에 대한 필요성이 증대되고 있다. 양극 산화법은 금속표면에 양극 전류를 인가하여 산화피막을 인위적으로 형성시켜줌으로써 내식성을 향상시켜 주는 방법으로서 산업적으로 널리 사용되고 있는 표면처리 방법 중의 하나이다. 본 연구에서는 주석산나트륨의 농도에 따른 AZ31 마그네슘 합금의 양극 산화 피막 형성 거동을 연구하였다. DC 전류를 인가하여 양극산화 피막을 형성하였으며, 피막형성 전압 및 형성된 피막의 두께, 표면 거칠기 및 피막의 구조 등을 분석하여 주석산나트륨 농도에 따른 양극산화 피막의 형성 특성에 대하여 자세하게 고찰하였다.

• Korean Journal of Human Ecology
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• v.14 no.3
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• pp.401-409
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• 2005

The purpose of this study is to investigate mothers' beliefs regarding children's literacy development and self-reported home literacy practices with their children. The instrument used for this study measured mothers' beliefs toward the whole language approach against the traditional approaches in children's literacy development. The total number of 340 mothers participated in this study who are sending their children to daycare centers of kindergartens in Seoul and its suburban area. Mean, Standard Deviation, frequency, Spearman's rho, and Kendall's tau were employed to analyze the data. The results showed that mothers' beliefs on the whole language approach have relationships with their home literacy practices, and their demographic characteristics - such as mothers' education, their spouses' education, and income - were also related with mothers' beliefs. The results of this study explore the inter-relationship of mothers' beliefs with home literacy practices, and also the importance of mothers' belief system on children's literacy learning at home.

• Journal of Families and Better Life
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• v.28 no.1
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• pp.119-130
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• 2010

The purpose of this study is to develop and evaluate a parent-child reading interaction program. Based on the importance of the parent-child relationship and the home literacy environment vis-a-vis the extent to which reading is encouraged, and with regard to the existing empirical research in this field, a five-session parent-child reading interaction program has been developed, targeting 18 parents with children enrolled in th lower grades of elementary school. The effectiveness of this program has been evaluated by a pretest and post test and then analyzed by a paired t-test. The findings are as follows: 1) Following the implementation of this program, there were improvements in scores related to the home literacy environment, the encouragement of reading, and the attitude of the child toward reading. 2) In addition, there was an increase in the level of the mother's "rational guidance" parenting while tendencies toward overprotective and hostile parenting traits declined. The importance of the parent-child relationship and home literacy environment concerning reading guidance was discussed.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.489-489
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• 2013

AF 코팅은 유리나 플라스틱과 같은 기재 표면을 특수 처리하여 지문과 같은 오염물질의 부착방지와 오염물질이 부착되더라도 쉽게 제거 가능하도록 하는 기술이다. 전자, 자동차, 건축, 섬유, 철강분야 등에 활용 가능한 중요기술로 박막의 발수 발유 기능을 부여하는 표면처리 기술이고, 코팅방법에는 진공증착, 스핀코팅, 딥코팅, 플로우 코팅, 스프레이 코팅 등이 있으며, 경화 방법이나 접촉각 등의 특성이 반영된다. 터치패널 등의 지문부착방지 기술은 불소계와 비불소계 재료로 구분할 수 있지만 지문을 쉽게 지울 수 있고, 오염 방지 기능과 내구성이 있으며, 우수한 광학특성을 유지하는 것이 과제라 할 수 있다. 그리고 항균성을 부여하는 기술도 개발되고 있다. 이런 터치패널의 강화유리에 AF 코팅한 제품은 핸드폰 글래스에 처음 적용하면서부터 실생활에 도입이 시작되고 있다. 이러한 AF 코팅을 스퍼터링 법을 이용하여 증착 시켰다. 기존에는 E-beam을 이용한 증착 방식이 주를 이루었지만, 스퍼터링 법을 이용함으로써 박막의 균일화 및 대량생산이 가능해졌다. 따라서 이 연구에서는 기존의 E-beam 방식과 sputtering 공정 중 ion source에 의한 전처리의 유무에 따른 박막의 특성을 비교하였다. 내부식성, 내마모성 시험을 거친 후, 접촉각을 측정하여 알아보았으며, 박막의 건전성 및 균일성은 FE-SEM을 이용하여 관찰하였다. 실험용 장비가 아닌 실제 생산장비인 직경 1,400 파이의 장비를 이용하여 증착하였으며 염수분무 및 내마모 시험 후, 기존 접촉각의 ${\pm}5^{\circ}$ 내외임을 확인 할 수 있었고, 박막의 건전성 또한 뛰어남을 알 수 있었다.