• Journal of the Korean Chemical Society
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• v.67 no.4
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• pp.296-305
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• 2023

This study analyzed the information-seeking behavior of preservice science teachers by observing the process of seeking information needed in a Socioscientific issues (SSI) debate class. Twenty-four fourth-year preservice science teachers participated in the study, and the SSI debate was conducted on the topic of biofuels. The results of the study revealed that preservice teachers go through the process of 'Searching', 'Reviewing', 'Interpreting', and 'Evaluating and Reorganizing' stages when seeking information. The searching stage is divided into identifying topics, role division, and standard setting for a search. The reviewing stage is divided into reviewing sources and reviewing contents. The interpreting stage is divided into interpreting an information and interpreting information from an integrating aspect. In addition, the evaluating and reorganizing stage is divided into evaluating information and reorganizing information. It was found that preservice teachers have difficulty reviewing information and interpreting multiple sources of information in an integrated aspect. Also, it was found that evaluating information activity among preservice teachers' information-seeking behavior affects the level of argumentation in discussions.

• Journal of the Korean Chemical Society
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• v.66 no.4
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• pp.305-322
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• 2022

In this study, a practice-based teacher education program was developed and applied to improve the TPACK of pre-service chemistry teachers. Also the program effect and obstacles were confirmed by measuring the development of TPACK. The participants of this study were 20 pre-service chemistry teachers of 3rd grade and 2 pre-service chemistry teachers of 4th grade who took chemistry education courses at K University located in Chungcheongbuk Province. The developed teacher education program consisted of four stages: preparation, rehearsal, practice, and reflection. The feedbacks from researchers and colleagues pre-service teachers were provided in preparation, rehearsal, and reflection stages. As a result of the study, the program of this study did not show an educational effect in the "constructive learning activities" of preservice teachers, but it was found to have an educational effect in "problem solving". In other words, in "constructive learning activity", most pre-service teachers were at 0 level before and after the program. The pre-service teachers designed the class to unilaterally provide technology to simply use it as a tool to explain subject content or revise misconceptions, and learners can passively acquire knowledge. However, in the case of "problem solving", the pre-service teachers who were at level 0 before the educational program changed to level 1. Before the program, the pre-service teachers designed classes to solve problems by memory without using technology, but after the program they planned classes that provides opportunities to approach and solve various problems through the technology presented by the teacher. However, there were not many pre-service teachers corresponding to level 2, which constitutes voluntary learning in which learners use technology to solve various problems while selecting and variously manipulating technology. In addition, as obstacles to the TPACK development of pre-service chemistry teachers, there were external factors such as lack of classroom support environment for TPACK implementation, lack of time for education planning, and inadequate technology competency. And there were internal factors such as perspectives of traditional education and negative attitude toward technology. In particular, the proportion of pre-service teachers who preceived inappropriate technical competency as an external obstacles of TPACK development was high. Therefore, it was necessary to develop an education program corresponding to type 2 or type 3 that enables TPACK development through TK for pre-service teachers.

• Journal of Korean Society of Environmental Engineers
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• v.28 no.6
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• pp.661-666
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• 2006

The compressive strength of a paste composed of a low-calcium Class F fly ash and alkaline activator solutions was investigated. These activator solutions, made with sodium hydroxide, water glass and water, have a very high $OH^-$ concentration. The composition of alkaline activator solution and temperature have been shown to notably influence the development of the compressive strength of the fly ash-cements paste. Compressive strength of 50 MPa could be achieved by curing of the fly ash at $60^{\circ}C$ for 48 hrs or $85^{\circ}C$ for 24 hrs. This study presented the optimum mixing ratio of Class F fly ash/sodium hydroxide/water glass as 25:8:2 in weight basis, and activator/fly ash as 0.6/1.0 for high strength paste.

• Journal of the Korea Institute of Building Construction
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• v.11 no.6
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• pp.547-556
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• 2011

The primary factors affecting concrete sulfate resistance are the chemical composition of the Portland cement, and the chemistry and quantity of mineral admixtures. To investigate the effect of those on the sulfate attack, the testing program involved several different mortar mixes using the standardized test, ASTM C1012. Four different cements were evaluated, including one Type I cement, two Type I-II cements, and one Type V cement. Mortar mixes were also made with mineral admixtures, as each cement was combined with three different types of mineral admixtures. One Class F fly ash, one Class C fly ash, and one ground granulated blast furnace slag (GGBFS) were added in various percent volumetric replacement levels. Expansion measurements were taken and investigated with the expansion criteria recommended by ASTM.

• Journal of The Korean Association For Science Education
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• v.19 no.1
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• pp.128-136
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• 1999

The effects of computer-assisted instruction (CAl) using molecular-level animation and worksheet upon students' achievement, conceptual understanding, and learning motivation were investigated. Treatment and control groups (2 classes) were selected from a girls' high school in Seoul, and taught about dissolution for 3 class hours. Before the instructions, the Patterns of Adaptive Learning Survey (PALS) was administered, and the grade for a previous science course was obtained. The PALS score was used as a covariate, and the other as a blocking variable. After the instructions, the achievement test, the conceptions test, and the Instructional Materials Motivation Scale (lMMS) were administered. Two-way ANCOVA results revealed that the scores of the CAl group in the achievement and the conceptions tests were significantly higher than those of the control group. The CAl group also performed better in all subtests of the IMMS except the subtest of relevance.

• Journal of Species Research
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• v.8 no.4
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• pp.319-336
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• 2019

During an investigation of unrecorded prokaryotic species in Republic of Korea, a total of 53 bacterial strains belonging to the class Gammaproteobacteria were isolated from soil, seawater, tidal flats, rhizosphere, salt ponds, beach sand, urine, manure, sediment, and animal intestine (Russian grayling butterfly [Hipparchia autonoe], mouse [Mus musculus], and sea bass [Lateolabrax japonicus]). Strains were identified to species using the 16S rRNA gene sequence, showing high similarity (>98.7%) with the closest bacterial species and forming a robust clade in the neighbor-joining phylogenetic tree. The 53 strains of Gammaproteobacteria in this study have not been report previously in Korea. Therefore, we describe 27 genera of 16 families in 7 orders: 13 strains in the order Alteromonadales, 1 strain in the order Chromatiales, 11 strains in the order Enterobacterales, 7 strains in the order Oceanospirillales, 10 strains in the order Pseudomonadales, 8 strains in the order Vibrionales, and 3 strains in the order Xanthomonadales. Gram reaction, strain ID, isolation source, and morphological and basic biochemical characteristics are described for each species.

• Journal of the Korean Chemical Society
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• v.51 no.2
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• pp.193-200
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• 2007

This study investigated the effects of situational context feedback in CAI upon students' conceptual understanding, science learning motivation, and the perception of CAI. Seventh graders (N = 114) from a coed middle school in Incheon were assigned to the situational context feedback CAI (SCF-CAI), the feedback CAI (F-CAI) and the CAI groups, and were taught about ‘three states of matter' and ‘motion of molecules' for 8 class hours. Prior science achievement test score used as a blocking variable. Two-way ANCOVA results revealed that the conceptual understanding test scores of the SCF-CAI group were significantly higher than those of the other groups. For the higher achievers, the scores of the F-CAI group in science learning motivation test were significantly higher than those of the CAI group. However, there was no significant difference among the lower achievers of three groups. The higher achievers in the SCFCAI and the F-CAI groups perceived the CAI more positively than those of the CAI group. The lower achievers in the FCAI group perceived the CAI more negatively than those of the other groups. Educational implications are discussed.

• Journal of the Korean Chemical Society
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• v.31 no.6
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• pp.555-566
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• 1987

Fifty ancient Korean coins originated in Yi Dynasty have been determined for 9 elements such as Sn, Fe, As, Ag, Co, Sb, Ir, Ru and Ni by instrumental neutron activation analysis and for 3 elements such as Cu, Pb, and Zn by atomic absorption spectrometry. Bronze coins originated in early days of the dynasty contain as major constituents Cu, Pb and Sn approximately in the ratio 90 : 4 : 3, whereas, those in latter days contain in ratio 7 : 2 : 0. Brass coins which had begun in 17 century contain as major constituents Cu, Zn and Pb approximately in the ratio 7 : 1 : 1. The multivariate data have been analyzed for the relation among elemental contents through the variance-covariance matrix. The data have been further analyzed by a principal component mapping method. As the results training set of 8 class have been chosen, based on the spread of sample points in an eigen vector plot and archaeological data such as age and the office of minting. The training set and test set of samples have finally been analyzed for the assignment to certain classes or outliers through the statistical isolinear multiple component analysis (SIMCA).

• Biomedical Science Letters
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• v.4 no.1
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• pp.11-25
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• 1998

The HLA genes located in the short arm of chromosome 6 specify heterodimeric glycoproteins involved in the regulation of the immune response. Recently, in the elucidation of HLA polymorphism, serological and cellular typing methods have been replaced by DNA typing using polymerase chain reaction (PCR). The purpose of this study was to establish the HLA DNA typing methods and determine gene frequencies of HLA molecules in Koreans. PCR-SSP (sequence specific primers) and PCR-RFLP (restriction fragment length polymorphism) techniques were used for the analysis of HLA-A, -B, -C, DRBl genes and HLA-DQAl, DQBl, DPBl genes, respectively. The results of B-lymphoblastoid cells used for control experiment were consistent with the previous data identified in the 11th International Histocompatibility Workshop. Seventeen, 23, 16, 8, 16, 13 and 37 types of HLA-A, B, C, DQAl, DQBl, DPBl and DRBl alleles were found, respectively, in a total of unrelated 120 Korean individuals. The most frequent HLA alleles were $A^*$02 (27.0%), B$^*$40 (17.6%), Cw$^*$01 (19.2%), DQAl$^*$0301 (32.1%), DQBl$^*$0303 (12.9%), DPBl$^*$0501 (31.3%) and DRBl$^*$1501 (9.2%) among Koreans. This study shows that DNA typing method using PCR technique is a relatively simple, fast and practical tool for the determination of the HLA-class I and II genes. Moreover, the data of HLA gene frequencies could be useful for the Korean database before clinical applications, including organ and unrelated bone marrow transplantation, anthropological study, disease association and individual identification.

• Bulletin of the Korean Chemical Society
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• v.31 no.5
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• pp.1355-1360
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• 2010

In order to search new inhibitors against farnesyl protein transferase (FPTase), a series of 2,3-bis-benzylidenesuccinaldehyde derivatives (1-29) were synthesized and their inhibition activities ($pI_{50}$) against FPTase were measured. From based on the reported results that the inhibitory activities of dimers 2,3-bis-benzylidenesuccinaldehydes were higher than those of monomers cinnamaldehydes, 3D-QSARs on FPTase inhibitory activities of the dimers (1-29) were studied quantitatively using comparative molecular field analysis (CoMFA) and comparative molecular similarity indices analysis (CoMSIA) methods. The statistical qualities of the optimized CoMFA model II ($r^2{_{cv.}}$= 0.693 and $r^2{_{ncv.}}$= 0.974) was higher than those of the CoMSIA model II ($r^2{_{cv.}}$ = 0.484 and $r^2{_{ncv.}}$ = 0.928). The dependence of CoMFA models on chance correlations was evaluated with progressive scrambling analyses. And the inhibitory activity exhibited a strong correlation with steric factors of the substrate molecules. Therefore, from the results of graphical analyses on the contour maps and of predicted higher inhibitory active compounds, it is suggested that the structural distinctions and descriptors that contribute to inhibitory activities ($pI_{50}$) against FPTase will be able to applied new inhibitor design.