• Korean Journal of Materials Research
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• v.32 no.12
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• pp.538-544
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• 2022

In existing ceramic mold manufacturing processes, inorganic binder systems (Si-Na, two-component system) are applied to ensure the effective firing strength of the ceramic mold and core. These inorganic binder systems makes it possible to manufacture a ceramic mold and core with high dimensional stability and effective strength. However, as in general sand casting processes, when molten metal is injected at room temperature, there is a limit to the production of thin or complex castings due to reduced fluidity caused by the rapid cooling of the molten metal. In addition, because sodium silicate generated through the vitrification reaction of the inorganic binder is converted into a liquid phase at a temperature of 1,000 ℃. or higher, it is somewhat difficult to manufacture parts through high-temperature casting. Therefore, in this study, a high-strength ceramic mold and core test piece with effective strength at high temperature was produced by applying a Si-Na-Ti three-component inorganic binder. The starting particles were coated with binary and ternary inorganic binders and mixed with an organic binder to prepare a molded body, and then heat-treated at 1,000/1,350/1,500 ℃ to prepare a fired body. In the sample where the two-component inorganic binder was applied, the glass was liquefied at a temperature of 1,000 ℃ or higher, and the strength decreased. However, the firing strength of the ceramic mold sample containing the three-component inorganic binder was improved, and it was confirmed that it was possible to manufacture a ceramic mold and core via high temperature casting.

• 월간산업보건
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• s.337
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• pp.56-60
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• 2016

• Bulletin of the Korean Chemical Society
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• v.20 no.4
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• pp.487-490
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• 1999

• 월간산업보건
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• s.373
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• pp.66-67
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• 2019

• 월간산업보건
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• s.372
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• pp.60-61
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• 2019

• Water for future
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• v.51 no.12
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• pp.49-55
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• 2018

• Bulletin of the Korean Chemical Society
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• v.19 no.2
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• pp.250-252
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• 1998

• Journal of Korea Foundry Society
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• v.42 no.5
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• pp.285-291
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• 2022

• Journal of Digital Convergence
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• v.16 no.12
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• pp.153-162
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• 2018

This paper analyzed the current level of the middle school academic achievement in Changwon City and explored the ways for improving academic achievement of the middle school in Changwon City. The data used in the analysis were the results of National Assessment of Educational Achievement of middle school students from 2013 to 2016 which was released on the school's information website(www.schoolinfo.go.kr) First, the analysis found that the academic achievement level of the middle school in Changwon City was not higher than those of Gwangju, Daejeon, and Ulsan, where the population size is similar. Second, the level of academic achievement among middle schools in Changwon City differed by year. Third, the level of academic achievement of middle school in Changwon City differed by district. Fourth, the educational achievement gap among middle schools in Changwon City existed by public and private school, as well as by male school, female school, and male and female Middle School. The paper suggested that schools with low ratio of proficient and above achievement levels should look for ways to raise the percentage of proficient and above achievement levels, and schools with higher rates of below basic achievement should make efforts to solve the problem.

• Journal of Global Scholars of Marketing Science
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• v.7
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• pp.1-23
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• 2001

Two of most important industries in Changwon, the distribution industry and the construction industry have been threatened by the recent economic downturn. Rehabilitating plans for traditional markets tend to focus on renovation of facilities rather than on the managerial solution. Traditional market plays vital roles as a social safety net and a source of development of regional economy. Modernization of facilities and differentiation of business areas are two most important issues for the revitalization of the traditional market. Traditional markets should adopt a strategy which can make a difference in characteristics of the market, regional culture, regional industry and consumer behavior of the region. Purposes of this study are: first, to understand characteristics of traditional markets in Changwon, second, to draw implications for administrative and financial supports for traditional markets in Changwon.