• Journal of the Korean Chemical Society
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• v.63 no.4
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• pp.289-306
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• 2019

The purpose of this study is to compare the contents of chemistry textbooks developed according to the 2015 revised curriculum with the contents of the 2009 revised curriculum to research the change in "the development and use of models". To do this, we analyzed 8 kinds of Chemistry I textbooks and 6 kinds of Chemistry II textbooks from the 2015 revised curriculum and compared them with 4 kinds of Chemistry I textbooks and 4 kinds of Chemistry II textbooks from the 2009 revised curriculum. The scope of the analysis was the explanations of the textbooks related to aqueous electrolysis experiments. In order to compare the contents regarding electrolytes when the same experiments are interpreted with different models, we analyzed contents of 4 kinds of middle school science textbooks from the 2015 revised curriculum and 9 kinds of middle school science textbooks from the 2009 revised curriculum. As a result of the analysis, the same experiment was explained by different models according to the grade level and unit, and all explanations were limited to a single model. Also, the tendency to limit the kinds of electrolytes for controlled experimental results is more pronounced in the 2015 revised curriculum than in the 2009 revised curriculum. From this results, we suggest that efforts are needed to reflect the "development and use of models" in chemistry textbooks developed according to the 2015 revised curriculum.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2012.04a
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• pp.137-140
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• 2012

현대의 건축 재료는 각종 고분자 화합물의 비중이 커지고 있어 건축 재료가 연소할 때 발생하는 가스의 성분비가 천연재료를 이용하던 과거의 건축물과 차이를 보인다. 실제로 근래의 건축재료 연소가스의 정성분석결과에서도 천연재료의 연소가스에서 발견되는 CO, $CO_2$ 외에도 HF, HCN, HBr, HCl, NO, $NO_2$, $SO_2$등의 화학종이 발견되고 있다. 이러한 화학종들은 고분자 화합물에서 발생하는 것으로 분석되며, 건축 재료에서 화합물의 비중이 높아지는 만큼 향후 이러한 화학종들이 건축물의 화재에서 대피의 주요 방해요인으로 작용할 수 있다. 이에 본 연구에서는 HF를 대상으로 동물 노출실험을 통하여 얻은 결과와 HF에 대한 기존연구를 비교 분석하여 HF의 독성에 대한 기초 연구를 수행하였다.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2003.11a
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• pp.455-456
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• 2003

광화학 스모그 현상을 재현하기 위한 메카니즘은 약 20,000개의 반응식과 수천개의 종이 포함되어야 하므로 자세한 반응 메카니즘을 포함하는 데는 한계가 있다(Dodge, 2000). 최근에 morphecule이라 부르는 대리종(surrogates)을 사용하는 방법(morphecule approach)이 개발되었다. 이 메카니즘은 반응 속도, 생성율, 생성물의 형태를 포함하여 lumped surrogates와 관련된 인자들이 모사하는 전체 시간 중 각 t시간 동안 일정하고 그 시간이후에는 인자들이 변화한다고 가정한다. 또한 특성이 비슷한 유기 화합물의 다양한 그룹을 표현할 때 morphecule이라 부르는 특정 화학종들을 사용한다. (중략)

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.10 no.1
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• pp.13-19
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• 2012

The long-lived fission products $^{79}Se$ and $^{99}Tc$ have been considered as the major concern nuclides for the disposal of radioactive waste because of their high solubilities and the existence of anionic species in natural water. In this study, the solubilities of $FeSe_2(s)$ and $TcO_2(s)$, known as respective Solubility Limiting Solid Phase (SLSP) of selenium and technetium, were measured in the KURT (KAERI Underground Research Tunnel) groundwater under various pH and redox conditions. And their solubilities and major species were also calculated using geochemical codes under conditions similar to experimental solutions. Experimental results and calculation for $FeSe_2$ show that the solubility of selenium was found to be below $1{\times}10^{-6}mol/L$ under the condition of pH 8~9.5 and Eh=-0.3~-0.4 V while the dominant species was identified as $HSe^-$. For $TcO_2$, the solubility of technetium was found to be $5{\times}10^{-8}{\sim}1{\times}10^{-9}mol/L$ in the solutions of pH 6~9.5 and Eh<-0.1 V, while the dominant species was $TcO(OH)_2$. However, when the Eh of the solution is -0.35 V, $TcO(OH)_3^-$ and $TcO_4^-$ are calculated as the dominant species at pH 10.5~12 and pH>12, respectively.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.1135-1139
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• 2017

Spatial distribution of chemical species in flame is a important indicator understanding the flame structure and combustion characteristics, and optical emission spectroscopy has been widely used for the measurement because of its simple and non-intrusive methodology. In this study, we suggest the feasibility of the measurement of chemical species (OH radical) distribution in rocket plume using optical emission spectrometer which was developed for the spatially resolved measurement along the line-of-sight. In order to predict the ground state concentration of species from the measured emission intensity by optical emission spectrometer, we consider thermal and chemical excitation mechanisms in flame, and assume thermodynamic equilibrium for the thermally excited species. We also present the spatial resolution and the correction of collection characteristics of the optical emission spectrometer depending on object distance.

• Journal of the Korean Electrochemical Society
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• v.27 no.1
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• pp.1-7
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• 2024

With the increasing demand for wearable sensors that are capable of point-of-care testing, paper-based sensors have been extensively studied. Paper is not only extremely cost-effective but also lightweight and flexible, and it is easy to apply conductive materials such as carbon and hydrophobic substances like wax to its surface. Moreover, the capillary action caused by cellulose fibers in paper allows the flow of liquid without help from external forces, making paper a particularly promising platform for wearable electrochemical sensors. Accordingly, paper-based sensors for detecting various analytes through electrochemical methods have been actively developed. Recently, paper-based electrochemical sensors that utilize electrochemiluminescence (ECL) or electrochromic materials for the optical read-out have been reported. This review introduces the basic fabrication methods and various application strategies of paper-based electrochemical sensors.

• Agrochemical news magazine
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• v.22 no.8 s.171
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• pp.50-51
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• 2001

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.7 no.3
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• pp.133-141
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• 2009

Study on the chemical speciation of uranium(VI) species, ${UO_2}^{2+}$, $UO_2(OH)^+$, ${(UO_2)}_2{(OH)_2}^{2+}$, ${(UO_2)}_3{(OH)_5}^+$, has been peformed by using time-resolved laser-induced fluorescence spectroscopy. Speciation sensitivity which depends on the excitation wavelength was investigated. We obtained the speciation sensitivity in the order of $10^{-9}$ M concentration of U(VI) compounds at the excitation wavelength of 266 nm. The fluorescence spectrum and lifetime of ${UO_2}^{2+}$ were carefully measured at pH 1 and ion strength of 0.1 M. The spectrum showed the four characteristic peaks located around 488, 509, 533, 559nm and the fluorescence lifetime of $1.92{\pm}0.17{\mu}s$. The wavelength shifts of fluorescence peaks and the change of lifetimes for uranium hydrolysis compounds were compared with those of ${UO_2}^{2+}$. We report on the characteristic features, the shifts of peaks to the longer wavelength direction and the prolonged lifetimes, in the fluorescence of the U(VI) hydrolysis compounds.

• Journal of the Korean Chemical Society
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• v.29 no.4
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• pp.356-364
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• 1985

Ab initio calculations with STO-3G method were carried out on isomers of isobutylene dianion and dilithioisobutylene, and geometry, energy and Mulliken population were discussed. Energy of reaction, ${\Delta}$E, for isodesmic processes involving these species and relative heats of formation, ${\Delta}H_f$, estimated with ${\Delta}$E have shown that the contribution of "Y-aromaticity" to the structural stabilization of Y-type dianion is a tenuous one but the alkylation appears to proceed via the Y-type dilithio compound.

• Journal of the Korean Chemical Society
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• v.64 no.1
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• pp.19-29
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• 2020

We analyzed the representations of acid-base models in 4 kinds of Chemistry I and 4 kinds of Chemistry II textbooks of the 2009 revised curriculum, and 9 kinds of Chemistry I textbooks and 6 kinds of chemistry II textbooks of the 2015 revised curriculum in this study. The problems of the textbook were divided into the problems of definitions and the representations of the logical thinking. As a result of the study, the lack of the concept of chemical equilibrium had a problem with the representation of reversible reactions in the definition of the Brønsted-Lowry model in the Chemistry I textbooks of 2009 revised curriculum, it also appeared to persist in Chemistry I textbooks of 2015 revised curriculum which contains the concept of chemical equilibrium. The representations of logical thinking were related to particle kinds of conservation logic, combinational logic, particle number conservation logic, and proportion logic. There were few problems related to representation of logical thinking in Chemistry I textbook in 2009 revision curriculum, but more problems of representations related to logics are presented in Chemistry I textbooks in 2015 revision curriculum. Therefore, as the curriculum is revised, the representations of chemistry textbooks related to acid and base models need to be changed in a way that can help students' understanding.