• Bulletin of the Korean Chemical Society
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• v.30 no.12
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• pp.3109-3112
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• 2009

• Bulletin of the Korean Chemical Society
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• v.34 no.2
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• pp.661-664
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• 2013

• Bulletin of the Korean Chemical Society
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• v.24 no.2
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• pp.239-242
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• 2003

• Journal of the Korean Chemical Society
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• v.51 no.1
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• pp.73-81
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• 2007

The purpose of this study was to find out chemistry teachers' perceptions on the aims and characteristics of the chemistry I course from the 7th national curriculum by means of investigating how frequently particular learning contents were selected and what the teachers' teaching styles were in order to find out how effectively teachers were working with the 7th national curriculum in teaching. For this study, data was collected by means of questionnaires, which was answered by 44 chemistry teachers in 40 different high schools. Results from this study are as follows: As for the perception on the aim and characteristics of chemistry I course, many chemistry teachers have already perceived that the aim of the course was to promote democratic citizens with the knowledge of chemistry. And the most appropriate way of teaching chemistry I course was inquiry-centered teaching such as experiment-practice and inquiry-discussion. However, these perceptions were not reflected when they actually taught students in the classroom. Instead, most of the class was concepts learning and there were a lot of differences in selecting learning contents among chemistry teachers. Furthermore, although chemistry I course was considered a good subject to make students have interest and curiosity in chemistry, it was not appropriate to make students understand the concepts of chemistry. Therefore, learning contents in chemistry I course need to improve. In conclusion, as the goal of 7th national curriculum of chemistry I course was to emphasize inquiry teaching, inquiry based teaching should be practiced in the class. Moreover, sufficient teacher training should be accompanied and alternative additional teaching contents should be developed. Finally teachers' experiences should be reflected in the national curriculum when it is revised.

• Journal of the Korean Chemical Society
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• v.49 no.6
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• pp.575-583
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• 2005

• Bulletin of the Korean Chemical Society
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• v.30 no.7
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• pp.1459-1462
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• 2009

Two new flavone glycosides, giraldiin A and B, together with three known compounds, annulatin, myricetin 3-O-$\alpha$- L-rhamnopyranoside and gallic acid, were isolated from the ethanol extract of the root of Pteroxygonum giraldii Damm. et Diels. The structures of giraldiin A and B are designated as 3'-($\alpha$-L-arabinopyranosyloxy)-4',5,5',7- tetrahydroxy-3-methoxyflavone and 4'-($\beta$-D-glucopyranosyloxy)-5,5',7-trihydroxy-2',3-dimethoxyflavone, respectively, on the basis of detailed spectroscopic analyses. The free radical scavenging activity of giraldiin A was evaluated by decolouring spectrophotometry of pentamethine cyanine dye (Cy5) with $Fe^{2+}-H_2O_2$ Fenton radical generating system. The results indicated the hydroxyl free radical scavenging activity of giraldiin A (E$D_{50}$ = 23.7 nmol/mL) is higher than that of some known antioxidants such as rutin, puerarin, daidzein and 2,6-di-tertbutyl-4-methylphenol.

• Bulletin of the Korean Chemical Society
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• v.34 no.2
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• pp.489-494
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• 2013

An improved method for the preparation of monomethine cyanine dyes with quinoline nucleus by one-pot three-component using 1-methyl-2-quinolinethione, quaternized 2- or 4-methylheterocyclic compounds and methyl p-toluenesulfonate as starting materials was described. Compared with the traditional methods, the new synthetic method reduced the reaction steps, shortened the reaction time, avoided the separation and purification of the intermediate and reduced cost. The dyes absorbed in the region 478.0-563.0 nm and had molar extinction coefficients of $1.3{\times}10^4-9.4 {\times}10^4L\;mol^{-1}\;cm^{-1}$. Their fluorescence maxima and Stokes shifts were in the range of 525.2-594.4 nm and 16.2-80.6 nm in different solvents, respectively. From the spectral properties of the dyes in different solvents, it could be found that the ${\lambda}_{max}$ of the dyes were shorter in protonic solvents, and showed hypsochromic shifts with the increase of polarity of the solvents.

• Bulletin of the Korean Chemical Society
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• v.33 no.1
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• pp.183-188
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• 2012

A blue phosphorescent $Ir(dfpypy)_3$ (dfpypy:fluorinated pyridine-pyridine ligand) complex with meridional configuration has been synthesized by newly developed effective method and its solid state structure and photoluminescence are characterized. For this complex, mer-$Ir(dfpypy)_3$, the glass-transition and decomposition temperatures appear at $160^{\circ}C$ and $384^{\circ}C$ respectively in TGA and DSC experiments, which indicates that this complex has high thermal stability. In a crystalline structure, an average Ir-C bond length of mer-$Ir(dfpypy)_3$ is slightly longer than that of fac-$Ir(dfpypy)_3$, which assumed to be due to the weak trans-influence. The absorption and emission spectra are observed more red-shifted in mer-$Ir(dfpypy)_3$ than fac-$Ir(dfpypy)_3$. In addition, the former is readily oxidized than the latter in electrochemical behavior.

• Bulletin of the Korean Chemical Society
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• v.33 no.1
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• pp.278-280
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• 2012

• Journal of Science Education
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• v.35 no.2
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• pp.119-126
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• 2011

The purpose of this study was to examine the effects of experimental learning using the small-scale chemistry (SSC) on high school students' academic achievement, scientific attitude and science-related attitude in high school chemistry I. For this study, two high school 2nd grade classes were divided into an experimental group and a control group. Experimental learning using the SSC in the experimental group, traditional experimental learning presented in the textbook in the control group were performed. The results showed that experimental learning using the SSC compared to traditional experimental learning was effective in improving academic achievement. The experimental learning also was effective in improving voluntary, patience, cooperativity in the scientific attitudes and social implications of science, attitude for science curriculum, attitude toward science in the science-related attitudes. Therefore, experimental learning using the SSC is necessary to actively utilize in high school chemistry curriculum.