• Analytical Science and Technology
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• v.8 no.4
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• pp.1069-1074
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• 1995

The application of scanning electrochemical microscopy to the imaging of surfaces in water and air and to the study of the electrochemistry of single molecules is discussed.

• Applied Chemistry for Engineering
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• v.27 no.4
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• pp.433-438
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• 2016

The current study evaluated the air quality of the smoking booth equipped with the air purification system consisting of photocatalysts and air filters by measuring the concentrations of hazardous substances of tobacco smoke such as CO, HCHO, $CH_3CHO$, PM10 and PM2.5. To enhance the removal efficiency of hazardous substances, an infrared ray was exposed to improve the reactivity of OH radical generated from the photocatalyst toward environmental tobacco smoke (ETS) gas phase hazardous materials. It was found that the smoking booth with the air purification system improved the removal efficiency of hazardous substances containing formaldehyde by 85.2% compared to that of the smoking booth without any purification systems. In addition, the removal efficiency of the fine dust after treatment was enhanced up to 89.4%.

• Journal of Korean Society for Atmospheric Environment
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• v.29 no.4
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• pp.407-438
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• 2013

Current status and future direction of air quality modeling for monitoring and forecasting air quality in East Asia were discussed in this paper. An integrated air quality modeling system, combining (1) emission processing and modeling, (2) meteorological model simulation, (3) chemistry-transport model (CTM) simulation, (4) ground-based and satellite-retrieved observations, and (5) data assimilation, was introduced. Also, the strategies for future development of the integrated air quality modeling system in East Asia was discussed in this paper. In particular, it was emphasized that the successful use and development of the air quality modeling system should depend on the active applications of the data sets from incumbent and upcoming LEO/GEO (Low Earth Orbit/Geostationary Earth Orbit) satellites. This is particularly true, since Korea government successfully launched Geostationary Ocean Color Imager (GOCI) in June, 2010 and has another plan to launch Geostationary Environmental Monitoring Spectrometer (GEMS) in 2018, in order to monitor the air quality and emissions in/around the Korean peninsula as well as over East Asia.

• Journal of the Korean Chemical Society
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• v.37 no.7
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• pp.635-641
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• 1993

Electrochemical cell, $Pt|air(PO_2=5.3{\times}10^{-3}atm)|Zr_{0.85}Ca_{0.15}O_{1.85}|air(PO_2= 0.21atm)|Pt$, has been designed to characterize the solid electrolyte and the temperature dependence of the electromotive force (EMF) has been measured in a temperature range of 600∼1000${\circ}$C. Solid electrolyte shows pure ionic conduction of the oxygen anion. The Fe-FexO, Co-CoO, Ni-NiO, and Cu2O-CuO electrodes have been prepared by mixing the 1 : 1 mole ratio of each metal and metal oxide and then by heating at 800${\circ}$C for 6 hours. Electrochemical cells, Pt│M(s), $MO(s)|Zr_{0.85}Ca_{0.15}O_{1.85}|air(PO_2=0.21atm)|Pt$, have been designed and the temperature dependence of the EMF has also been measured in the same temperature range. The changes of the thermodynamic state functions for the formation of the metal oxides are calculated from the electromotive forces and their temperature dependences. The material properties of the oxide systems are also discussed with the function changes.

• Bulletin of the Korean Chemical Society
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• v.35 no.5
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• pp.1465-1468
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• 2014

In this study, an intermediate temperature ionic conductor, $Ce_{0.95}Eu_{0.05}P_2O_7$, was prepared by solid state reaction. The variation of conductivities with the pressure $pH_2O$ or time were studied. The highest conductivity of $Ce_{0.95}Eu_{0.05}P_2O_7$ sample was observed in dry air atmosphere at $300^{\circ}C$ to be $1.1{\times}10^{-4}S{\cdot}cm^{-1}$ and in wet air atmosphere ($pH_2O=7.4{\times}10^3Pa$) at $100^{\circ}C$ to be $1.4{\times}10^{-3}S{\cdot}cm^{-1}$, respectively. The log ${\sigma}$ ~ log ($pO_2$) plot result indicated that $Ce_{0.95}Eu_{0.05}P_2O_7$ was almost a pure ionic conductor under high oxygen partial pressure and a mixed conductor of ion and electron under low oxygen partial pressure.

• Journal of the Korean Vacuum Society
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• v.12 no.S1
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• pp.70-73
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• 2003

Sum-frequency vibrational spectroscopy has recently been used to investigate the surface of the various polymers and was able to find the chemical compositions and structures specific to the surface. Here we report our studies on two specific polymer samples to demonstrate its capability. Polyimide thin films were made by spin coating on fused quartz and $CaF_2$ substrates. The sum-frequency signal originating mainly from the air/polymer interface showed markedly different spectra, indicating the structural change of the polymer surface depending on the underlying substrate. Various polyethylene surfaces were also investigated by sum-frequency vibrational spectroscopy. The surface of polyethylene samples in the CH-region showed different sum-frequency spectra, presumably due to the trace amount of additives having much higher concentration at the air/polymer interface. These examples demonstrate the surface and interface of the polymer could have different structure and chemical composition from those of a bulk, which can be studied effectively by surface nonlinear optical spectroscopy.

• Applied Chemistry for Engineering
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• v.16 no.5
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• pp.719-723
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• 2005

Organic-inorganic hybrid mesoporous materials were prepared by co-condensation of organosilanes with tetraethyl orthosilicate (TEOS) or 1,2-bis(triethoxysilyl) ethane (BTSE). Their removal capability of volatile organic compounds (VOCs) in the air was evaluated and compared with that of inorganic hydrophilic mesoporous material, SBA-15 that was prepared with TEOS only. It was found that the increased hydrophobicity of mesoporous materials due to the presence of organic group, could enhance the VOCs removal by adsorption in the air. An organic-inorganic hybrid material prepared by the co-condensation of BTSE/phenyl triethoxysilane (90/10 by weight) was a typical example of superior adsorbent. It was also observed that these organic-inorganic hybrid materials can be utilized as absorbents for the removal of oil dispersed in water.

• Journal of the Korean Chemical Society
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• v.65 no.5
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• pp.333-346
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• 2021

In this study, we developed education materials using history of science related to the experiment of 'Boyle's air pump' and the Boyle and Hobbs' debate of vacuum to find out the perceptions of NOS by pre-service chemistry teachers. For the study, 29 pre-service chemistry teachers at a college of education in Chungcheongbuk-do were selected. As RFN items that were related to the contextual situation developed in this study, items in the categories of 'Aims and Values', 'Scientific practices', 'Scientific Methods among Educational Applications' and 'Social-Institutional Aspects among Educational Applications' were selected. Through the items of RFN, the perceptions of pre-service teachers in non-contextual situations were investigated. Then we presented the pre-service teachers with the situation related to Boyle's experiment on air pump and Boyle and Hobbes' debate over vacuum. In addition, their perception of NOS was examined in contextual situations related to RFN items. Responses to the items, experimental results related to Boyle's Law, group discussion, and interview data were collected as data. As a result of the study, it was found that pre-service teachers had informed perceptions in most of the items, but cases with naive views or mixed views were found in context experimental situations. This study can contribute to the NOS education for pre-service chemistry teachers by development of context situation education materials related to NOS and by finding out their perceptions in the non-contextual and contextual situation.

• Journal of the Korean Applied Science and Technology
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• v.30 no.3
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• pp.518-527
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• 2013

5,6-dihydroxyindole was easily oxidation with air and light Conditions. Availability of 5,6-dihydroxyindole was studied for hair dye as a precursor of melanin. This study used wet and dry coating process to stabilize 5,6-dihydroxyindole. In wet process used dimethicone and cyclometicone, the 5,6-dihydroxyindole had darkened through the drying process at $58^{\circ}C$. Wet coating process was inappropriate to stabilize the coating. In dry coating process, shea butter coating was stable until 3 days. Dextrin palmitate was most efficient ingredient to prevent oxidation by sun light and air until 7days. Oxidation test with 1.0% and 1.5% of dextrin palmitate was not different under conditions of sun light and air and was not dependent on contents. Vitamin E acetate under conditions of sun light and air, there were no significant effect in preventing oxidation.

• Journal of the Korean Society of Safety
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• v.25 no.1
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• pp.17-21
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• 2010

The chemistry and ignition delay of hydrogen/air/HFP premixed mixtures was investigated numerically with unsteady perfectly stirred reactor(PSR). The detailed chemistry of 93 species and 817 reaction mechanism was introduced for hydrogen/air/HFP mixtures. The results shows the temporal concentration variations of major or reactants such as hydrogen and oxygen during autoignition were similar to the spatial distribution of premixed flame while water vapor produced at the ignition temperature was decomposed later, which can be clarified with the relate species production rates that the the re-growth (or shoulder) of OH concentration is a result of F radicals attacking $H_20$ forming OH and HF. For the stoichiometric $H_2$/air mixture inhibited by 20% HFP, HFP thermal decomposition reaction prevails over the radical attack such as H at initial stage. Even though relatively large HFP addition contributes to delay the ignition, chemical effect on the ignition delay is not effective because of late thermal decomposition of HFP. The most small ignition delay was observed at a slightly fuel lean condition ($\phi$ = 0.9), and temperature dependency of ignition delay was clearly shown near 900 K.