• Journal of the Korean Ceramic Society
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• v.52 no.3
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• pp.180-185
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• 2015

Low-cost ceramic membrane supports with pore sizes in the range of $0.52-0.62{\mu}m$ were successfully prepared by uniaxial dry compaction method using inexpensive raw materials including kaolin, bentonite, talc, sodium borate, and alkaline-earth oxides in carbonate forms (e.g., $MgCO_3$, $CaCO_3$, and $SrCO_3$). The prepared green supports were sintered at $1000^{\circ}C$ for 8 hr in air. The effect of alkaline-earth oxide additives on the flexural strength of clay-based membrane supports was investigated. The porosity of the clay-based membrane supports was found to be in the range of 33-34%. The flexural strength of the clay-based membrane supports with 1% alkaline-earth carbonates was found to be in the range of 42.8-52.7 MPa. The addition of alkaline-earth carbonates to clay-based membrane supports resulted in large increases (47-80%) in the flexural strength of the membrane supports, compared to that of membrane supports without alkaline-earth carbonates. The typical flexural strength of the clay-based membrane support with 1% $SrCO_3$ was 52.7 MPa at 33.8% porosity.

• Journal of the Korean earth science society
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• v.36 no.4
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• pp.390-403
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• 2015

The purpose of this study was to explore discursive-epistemic mechanisms in high school earth science lessons. A total of 11 video recordings of earth science lessons were collected from three inservice high school teachers. The video recordings were all transcribed and analyzed by employing the discourse analysis framework used in relevant previous studies. In analysis, we identified discursive-epistemic mechanisms as functional assemblies for fulfilling particular epistemic functions in the earth science lessons. The characteristics of these mechanisms were described according to their epistemic functions. The findings of the study were compared with those of previous studies to highlight the characteristics of discursive-epistemic mechanisms in the earth science classrooms. Analyses of middle school science lessons and of science lessons in alternative forms, as well as studies using extended research methods such as indepth interviews with teachers, were suggested as implications for future research.

• Journal of the Korean earth science society
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• v.42 no.4
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• pp.412-424
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• 2021

Understanding the distribution of heavy metals in sediment is necessary because labile heavy metals can partition into the water column and bioaccumulate in aquatic organisms. Here we investigated six heavy metals (Co, Cu, Mn, Ni, Pb, and Zn) in sediment cores using a five-step sequential leaching method to examine the occurrence of heavy metals in the sediment. The results showed that all elements, except Mn, are depleted in the exchangeable and carbonate fractions. However, heavy metal concentrations are much higher in the Fe-Mn oxide and organic matter fractions, especially for Cu, indicating enrichment in the organic matter fraction. Furthermore, contamination parameters (contamination factor and geoaccumulation index) indicate that Mn contamination is high, primarily derived from anthropogenic sources, presenting a potential risk to ecosystems in the Nakdong River.

• Journal of the Korean earth science society
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• v.18 no.6
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• pp.293-293
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• 1997

• Journal of the Korean earth science society
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• v.40 no.5
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• pp.518-537
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• 2019

This study examined the implications of a place-based earth science program integrated with Mathematics. 11 pre-service earth science teachers and 22 middle school students participated in the service education activities of earth science for 30 hours focusing on the measurement of the earth's size through earth science experiments as part of the middle school curriculum. In order to minimize errors that may occur during the earth's size measurement experiments using Eratosthenes's shadows length method of the ancient Greek era, the actual data were collected after triangulation ratios were conducted in the locations of two middle schools: one in remote metropolitan and the other in rural area. The two schools' students shared the final estimate result. Through this process, they learned the mathematical method to express the actual data effectively. Participants, experienced the importance and difficulty of the repetitive and accurate data acquisition process, and also discussed the causes of errors included in the final results. It implies that a Place-Based Earth Science Program activity can contribute to students' increased-understanding of the characteristics of earth science inquiry and to developing their problem solving skills, thinking ability, and communication skills as well, which are commonly emphasized in science and mathematics in the 2015 reunion curriculum. It is expected that a place-based science program can provide a foundation for developing an integrated curriculum of mathematics and science.

• Journal of the Korean earth science society
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• v.23 no.3
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• pp.207-220
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• 2002

The purpose of this study was to verify the trends of Korean students' achievement of earth science, especially the gender differences, in recent two international comparative studies, TIMSS-R (The Third International Mathematics and Science Study-Repeat) and PISA 2000 (Programme for International Student Assessment). To achieve this purpose, the 33 earth science items in TIMSS-R and 13 earth and environmental science items in PISA 2000 were analyzed. As a result of the comparison between Korean- and international percent correct, Korean students showed especially higher achievement in close-ended items or items required 'understanding of simple information.' Korean students, in particular Korean male students, also showed higher achievement in items of data interpretation. On the other hand, Korean students, in particular Korean female students, showed relatively lower achievement in astronomy items. The serious gender differences occurred in all aspects of items, regardless of item content, item format, and performance expectations.

• Journal of the Korean Society of Earth Science Education
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• v.2 no.1
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• pp.62-79
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• 2009

In the present study I developed the test for earth scientific creativity level and verified means to measure scientific creativity. I developed 22 test items and after being examined by science education specialist, 11 items were finally established, and these were applied to 104 middle students. Each answer paper was graded according to the standard answer that I developed and the results of analysis are as follows. First, to verify the validity of measuring means I figured out content validity. The content validity about test items and adequacy of evaluation goal was examined by 1 science education specialist and 3 middle school science teachers, 6 education graduate students. As a result of validity verification, the content validity was 82.7% and it showed that the test of earth scientific creativity was valid for evaluation goal and sub-factors of creativity. Second, to verify reliability of measuring means, I analyzed internal consistency of the test sheet of earth scientific creativity after finding correlation coefficient and Cronbach's $\alpha$. Cronbach's $\alpha$, the internal reliability coefficient, was 0.848. Therefore, it was verified that this test sheet of earth scientific creativity is reliable to measure the creativity of the middle school students. The correlation between sub-factors of creativity was statistically significant, and for the relation between the variables related to creativity, the originality was the most significant. This shows that in the procedure of scientific creativity and studying science, originality should be the most important factor.

• Journal of the Korean earth science society
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• v.34 no.6
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• pp.453-455
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• 2013

• Journal of the Korean earth science society
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• v.31 no.7
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• pp.813-826
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• 2010

The purpose of this study is to investigate discrepant Earth Science terms in high school curriculums and to explore the alternative to those terms. In this study, we defined discrepant terms as different terms which had the same meaning in Earth Science textbooks. Discrepant terms were compared with terms in references and precedent studies, and the preference by 284 of teachers and students was investigated. The results of this study are as follows: A number of discrepant terms were found in references as well as high school textbooks. Participants preferred terms that are more understandable, were learned previously, and were correct to loanword orthography. As for the cases of discrepant terms caused by different notation of proper nouns or different references and background knowledge, the alternative could be explored by the rule of loanword orthography or the journal publications. In conclusion, confusion may be reduced by utilizing common terms that are both based on authorized theory and easy to convey the meaning.

• Journal of the Korean earth science society
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• v.30 no.5
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• pp.605-610
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• 2009

Cupressinocladus sp. found from the upper part of the Jinju Formation of the Shindong Group, Korea is described here based on the newly found leafy shoots. This species is characterized by the branched leafy shoot with decussate scale leaves. The presence of Cupressinocladus in the Jinju Formation indicates that the Early Cretaceous flora-sites in Eastern Eurasia are in a close association with territories of the mixed-type floras. The finding of this species records the first report for the Nakdong flora.