• Journal of the Korean Chemical Society
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• v.61 no.4
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• pp.204-210
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• 2017

In this study, we analyzed the descriptions of the electron movement model and the oxidation number change model presented in the 2009 revised curriculum and textbooks. We also investigated chemistry education major teachers' conceptions of limitations of each model. The electron movement model and oxidation number change model were presented in the curriculum and the textbooks. However, hybrid model was also presented which fail to grasp the limitation of each model. The hybrid model explains redox reactions of covalent bond compounds by electron movement model or even if it explains redox reactions by oxidation number change model, this explanations have the problem of confusing the virtual electron movement with the actual electron movement. A questionnaire and interviews were conducted to investigate chemistry education major teachers' perceptions of redox reactions. As results, many teachers did not recognize the limitations of each model and had difficulties to distinguish redox reactions from acid-base reactions because of the hybrid model.

• Bulletin of the Korean Chemical Society
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• v.32 no.2
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• pp.559-565
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• 2011

The following noble series of statistical copolymers, poly[(2-(3-thienyl)ethanol n-butoxycarbonylmethylurethane)-co-3-hexylthiophene] (PURET-co-P3HT), were synthesized by the chemical dehydrogenation method using anhydrous $FeCl_3$. The structure and electro-optical properties of these copolymers were characterized using $^1H$-NMR, UV-visible spectroscopy, elemental analysis, GPC, DSC, TGA, photoluminescence (PL), and cyclic voltammetry (CV). The statistical copolymers, PURET-co-P3HT (1:0, 2:1, 1:1, 1:2, 1:3), were soluble in common organic solvents and easily spin coated onto indium-tin oxide (ITO) coated glass substrates. Hybrid bulk heterojunction photovoltaic cells with an ITO/G-PEDOT/PURET-co-P3HT:PCBM:Ag nanowires/$TiO_x$/Al configuration were fabricated, and the photovoltaic cells using PURET-co-P3HT (1:2) showed the best photovoltaic performance compared with those using PURET-co-P3HT (1:0, 2:1, 1:1, 1:3). The optimal hybrid bulk heterojunction photovoltaic cell exhibits a power conversion efficiency (PCE) of 1.58% ($V_{oc}$ = 0.82 V, $J_{sc}$ = 5.58, FF = 0.35) with PURET-co-P3HT (1:2) measured by using an AM 1.5 G irradiation (100 mW/$cm^2$) on an Oriel Xenon solar simulator (Oriel 300 W).

• Bulletin of the Korean Chemical Society
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• v.34 no.3
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• pp.827-830
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• 2013

Investigation of an organic extract of the fruits Schisandra wilsoniana led to the isolation of two new highly oxygenated nortriterpenoids, named schilancidilactones V-W (1-2). Their structures were elucidated by spectroscopic evidence. Compounds 1-2 feature a double bond between C-7 and C-8 compared with related known nortriterpenoids isolated from the genus Schisandra. Compounds 1 and 2 were tested for their anti-HIV-1 activities and cytotoxicity. The results revealed that compounds 1 and 2 showed moderate anti-HIV-1 activities with $EC_{50}$ 3.05 and 2.87 ${\mu}g/mL$, respectively, and compound 1 showed high cytotoxicity against KB and MDA-MB-231 cell with $IC_{50}$ values of 3.18 and 5.22 ${\mu}M$, respectively.

• Bulletin of the Korean Chemical Society
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• v.31 no.10
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• pp.2786-2790
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• 2010

Three new oleanane-type triterpene saponins (1, 2 and 3) were isolated from aerial parts of Gladiolus gandavensis, along with two known compounds (4 and 5). Their structures were elucidated as 29-O-($\beta$-D-glucopyranosyl)-$2{\beta}$,$3{\beta}$-dihydroxyolean-12-en-28-oicacid(1), 3-O-($\beta$-D-xylopyranosyl)-29-O-($\beta$-D-glucopyranosyl)-12-en-28-oic acid (2), and $2{\beta}$,$3{\beta}$,29-trihydroxyolean-12-en-28-oic acid 28-O-[$\beta$-D-glucopyranosyl($1{\rightarrow}2$)-($\alpha$-L-rhamnopyranosyl($1{\rightarrow}6$))-$\beta$-D-glucopyranosyl] ester (3), by spectroscopic methods, and by comparison with known analogues. These oleanane-type triterpene saponins glycosidated at C-29 were not obtained frequently.

• International Journal of Advanced Culture Technology
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• v.11 no.3
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• pp.211-224
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• 2023

This study surveyed 2nd graders of B high school and 1st graders of A university in Gyeongnam on factors such as behavior control and interaction in non-face-to-face classes, easy or difficult concepts presented in chemistry I and general chemistry textbooks. Based on the results of the survey, the effect of changes in the difficulty level of concepts presented in chemistry I and general chemistry and changes in class types (face-to-face and non-face-to-face) on students' academic achievement by level was compared and analyzed. In the face-to-face class, the average score between the first and second semesters was similar according to the change in the difficulty of the concepts presented in chemistry I and general chemistry. In the non-face-to-face class, the average score of chemistry I in the second semester was quite low, and the average score of general chemistry was rather high. In non-face-to-face classes, the average score of chemistry I in the second semester of low-level students was significantly lowered due to changes in the difficulty of the concept and changes in class types on academic achievement by level. In the case of 10% of students at the lower level, the academic achievement of chemistry I decreased in both the second semester regardless of the changes in the difficulty level of concepts and the changes in class types.

• Journal of the Korean Chemical Society
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• v.43 no.3
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• pp.340-350
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• 1999

This study was to analyze the articulation between chemistry contents of science textbooks at elementary and middle school level, to survey students ? perceptions on chemistry concepts, to establish guidelines for science textbooks that not only meet the needs of learners but also fit in a coherent way. In order to do this, we analyzed links of the aims and the organization of chemistry contents of elementary and middle school science textbooks, we also surveyed students' perceptions on chemistry concepts students had retained. The study revealed that the 6th middle school curriculum was almost a duplicate of the elementary school syllabus. And there was no interrelation between the organization of chemistry contents and the aim of the chapter which built up a logical picture of the world at a molecular level. It was also found that the lack of coherence between science textbooks in elementary and middle school was a major cause of student difficulty.

• Bulletin of the Korean Chemical Society
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• v.14 no.6
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• pp.663-664
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• 1993

• Bulletin of the Korean Chemical Society
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• v.15 no.3
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• pp.263-265
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• 1994

• Bulletin of the Korean Chemical Society
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• v.15 no.4
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• pp.291-293
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• 1994

• Journal of the Korean Chemical Society
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• v.46 no.5
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• pp.450-468
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• 2002

As the computer is popularized in individual and society, it is using in a many of area. In particular, there are many materials to learn a science knowledge using multimedia through computer. Many of them are web-based learning materials, which are developed by Java or Flash. Since the technology of the representation, storage, com-putation and communication in computer make progress, the environment of education is also developed. Especially, the internet and VR technology will cause the education to change. A key feature of VR is real-time interactivity, in that the computer is able to detect student input and instantaneously modify the virtual world. It is reported that using the VR simulation in chemistry education can increase student engagement in class, promote understanding of basic chem-ical principles, and augment laboratory experience. In this study, application way of the virtual reality technology in chemistry education is examined.