• Journal of the Korean Chemical Society
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• v.53 no.4
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• pp.445-452
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• 2009

In this study, the influences of the context of discrepant events on the conceptual change process using cognitive conflict strategy were investigated in terms of students' cognitive and motivational variables such as cognitive conflict, situational interest, attention, effort, conceptual understanding. A preconception test was administered to 536 seventh graders. A test of response to a discrepant event and a situational interest questionnaire were then administered. The context of discrepant events, either scientific or everyday, was randomly presented to the subjects. After learning the concept of density, the tests of attention, effort, and conceptual understanding were administered. The reponses of 194 students who had been found to possess the target misconception were analyzed. The results revealed that the scientific-context discrepant event induced higher cognitive conflict than everyday-context one. The context of discrepant events, however, did not show significant correlations with situational interest, attention, effort, and/or conceptual understanding. The result of path analysis indicated that the context of discrepant events both directly influenced cognitive conflict and indirectly influenced conceptual understanding via cognitive conflict.

• Journal of Climate Change Research
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• v.3 no.2
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• pp.101-116
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• 2012

Green management is, as the response to climate changes emerges to a global issue, a concept which reduction of greenhouse gases, alternative energy development and other low-carbon green growth factors are added on the existing environmental management. Also as discussions on the performance measurement of firms' domestic and international green managements proliferate and the importance of understanding, analyzing and evaluating firms' environmental maintenance rises, variety forms of green management performance measurement indicators are being developed and practiced. However, specific implementation methodologies about green management have been lacking. Hence in this research, In order to have objective evaluations on firms' green managements through the proposed indicator, AHP(Analytic Hierarchy Process) and experts' survey on weight dependence were applied. Sustainability reports and other associated documents of ten major oil/ chemical corporations of in and out of the country were analyzed and corporations were evaluated and compared through weight differentiated indicator subsections.

• Fire Science and Engineering
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• v.26 no.2
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• pp.75-83
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• 2012

An experimental study was conducted to investigate the effects of change in heat release rate on unsteady fire characteristics of under-ventilated fire in a semi-closed compartment. A standard doorway width of the full-scale ISO 9705 room was modified to 0.1 m and the flow rate of heptane fuel was increased linearly with time using a spray nozzle located at the center of enclosure. Temperature, heat flux, species concentrations and heat release rate were continuously measured and then global equivalence ratio (GER) concept was adopted to represent the unsteady thermal and chemical characteristics inside the compartment. It was observed that there was a significant difference in unsteady behavior between global and local combustion efficiency, and the GERs predicted by ideal and measured heat release rate were also shown different results in time. The unsteady behaviors of temperature, heat flux and species concentrations were represented well using the GER concept. It was important to note that CO concentration was gradually decreased with the increase in GER after reaching its maximum value in the range of 2.0~3.0 of global equivalence ratio. In addition, the experimental data on unsteady thermal and chemical behaviors obtained in a semi-closed compartment will be usefully used to validate a realistic fire simulation.

• Journal of the Korean Chemical Society
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• v.50 no.2
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• pp.141-152
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• 2006

In this study computer assisted instruction materials for the ‘Solution' chapter in high school chemistry II textbook were developed based on a view of particle and analyze the effect of the materials on 10th and 11th high school students. The contents of developed materials are dissolution, vapor pressure, the change of boiling point and freezing point, osmosis, and so on which are the major contents of Solution chapter in high school chemistry II textbook. Materials were developed with using animation and simulation for students understanding of the phenomena with a particle view point. Many phenomena in a solution were not simplified by colligative property of solution, but tried to explain by the concept of attraction between solute and solvent molecules. This computer assisted learning materials were developed using Flash 5.0 and Flash 6.0 Action Script. Educational effects of the materials on 10th and 11th grade students represented statistically meaningful increase of concept understanding. Especially the materials were effective to the transition stage or formal stage students in 10th grade and formal stage or the natural science major students in 11th grade.

• Journal of the Korean Chemical Society
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• v.56 no.2
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• pp.290-296
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• 2012

This study analyzed the research papers published in three (2 domestic and 1 foreign) journals, in order to understand the recent trend of chemistry education research. We selected Journal of the Korean Chemical Society (JKCS) and Journal of the Korean Association for Science Education (JKASE) as the domestic journals, and Journal of Chemical Education (JCE) as a foreign journal. The papers published from 2000 to 2009 were analyzed. As the result, the chemistry education research theme focused on 'teaching method and education technology', 'learner's characteristics', and 'chemical concept and experiment' in the order of frequency. The research on 'curriculum and textbooks' was performed often in JKCS reflecting Korean social environment. The most researched chemistry education goal was the 'conceptual understanding/change' followed by 'achievement/grade' in JCE and 'experiment/inquiry skill' in JKCS, and 'attitude/interest/motivation' in JKASE. The research subjects were focused to 'middle or high school students' in JKCS, in contrast to the 'university students' in JCE. More concern to the higher education is required in the domestic research. The most frequently used research method was 'survey/ examination' followed by 'experimental research' in JCE and JKASE and 'data/material analysis' in JKCS. We discussed the implication on future chemistry education research.

• Korean journal of applied entomology
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• v.60 no.1
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• pp.1-13
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• 2021

The concept of integrated pest management (IPM) first developed in the 1950s, and the concept of economic control via pest management was established in the 1960s. Research on IPM began in the United States and Europe, and IPM studies in Korea started with citrus insects and paddy field pests following the distribution of high-yield varieties of rice. Apple IPM in Korea began with research on pest control using chemical pesticides and pesticides resistant to insect pests, studies on the ecology of insect pests and their natural enemies, and the exploitation of sex pheromones on insect pests. Since the 1990s, IPM research and field projects have been carried out simultaneously for farming households. In the 2000s, the development of pest monitoring and forecasting models centered on mating disturbances, database programs for pests, and networks for sharing information. IPM technology has expanded via the development of unmanned forecasting systems and automation technologies in the 2010s.

• Journal of the Korean Chemical Society
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• v.46 no.3
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• pp.265-278
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• 2002

A concept test was administered to college students and teachers to identify their understanding of chemical equilibrium and equilibrium shift. The subjects were 53 freshmen in the General Chemistry class, 28 juniors in the Physical Chemistry class and 26 seniors from a university and 10 high school teachers in Seoul. Test items include the calculations of partial pressure and concentration of the gas in the mixture, the equilibrium constant cal-culation and the prediction of equilibrium shift when an inert gas is added to the gaseous reaction system, and the equilibrium concentration calculation and the prediction of equilibrium shift when water or common ion is added to the weak acid solution. The test was focused to identify whether the subjects can predict equilibrium shift using the reaction quotient change for the situations in which Le Chatelier principle is difficult to apply. The results showed that the achievements of teachers and juniors were significantly higher than those of freshmen and seniors. Many stu-dents had difficulties in predicting equilibrium shift using the reaction quotient while they could calculate partial pres-sure and concentration for the same situation. It means they are lack of conceptual understanding of chemical equilibrium shift.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.07a
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• pp.247-251
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• 2004

Chemical-Mechanical Polishing(CMP) especially is becoming one of the most important ULSI processes for the 0.25m generation and beyond. And there are many elements affecting CMP performance such as slurry, pad, process parameters and pad conditioning. Among these elements the CMP pad is considered one of the most important because of its change. But the surface of the pad has irregular pores, so there is non-uniformity of slurry flow and of contact area between wafer and the pad, and glazing occurs on the surface of the pad. So we make CMP pad with micro structure using micro molding method. This paper introduces the basic concept and fabrication technique of CMP pad with micro-structure and the characteristic of polishing. Experimental results demonstrate the removal rate, uniformity, and time vs. removal rate.

• Proceedings of the KWS Conference
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• 2009.11a
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• pp.197-201
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• 2009

A lot of work is carried out concerning to acicular ferrite formation in the weld metal of high strength and low-alloy steel. Those results are suggesting that oxides that contain titanium elements provides nucleation site of intragranular ferrite, referred as acicular ferrite. Thus, when intragranular ferrite is expected to form in heat-affected zone, oxide containing titanium element should be formed in the steel. However, normal steel is deoxidized by using aluminum element (Al-killed steel) with little oxygen content. It means almost oxygen is deoxidized with aluminum elements. In the present work, in order to form the acicular ferrite in the heat affected zone, with the same concept in the case of weld metal, the steel deoxidized with titanium element (titanium killed-steel) is prepared and the acicular ferrite formation is observed in detail by using laser-conforcal microscopy technique. The confocal technique makes it possible that the morphological change along the phase transformation from austenite to ferrite is in-situ tracked. Thus, the inclusion that stimulated the ferrite nucleation could be directly selected from the observed images, in the HAZ of the Ti-killed steel. The chemical composition of the selected inclusion is analyzed and the nucleation potential is discussed by changing the nucleation site with boron element. The potency for the ferrite nucleation is summarized and the existence of effective and ineffective manganese sulfide for nucleation is made clear.

• Transactions of Materials Processing
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• v.24 no.6
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• pp.395-399
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• 2015

A microstructure-based finite element simulation was conducted to predict the plastic strain ratio (R-value) of a dual-phase (DP) steel. The representative volume elements (RVEs) concept was adopted for the image-based FE modeling and a 3D model was constructed using sequential 2D images. Each phase was considered with the von-Mises yield criterion and the Swift model. The Swift parameters were defined by the empirical equations based on the chemical composition. The developed model was applied to analyze the effect of residual stress on the R-value and stress distribution. In order to consider the residual stress development after cold rolling, 10 % compression was applied in the thickness direction and unloaded before the tensile stress was applied in the rolling direction. The results showed a reasonable prediction for the R-value evolution: a sharp increase at small strains was well described and a transition followed in the downward direction. The R-value evolution was analyzed using the stress distribution change on the π-plane