• Journal of Microbiology and Biotechnology
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• v.18 no.1
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• pp.145-152
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• 2008

A cell-based in vitro exposure system was developed to determine whether oxidative stress plays a role in the cytotoxic effects of volatile organic compounds (VOCs) such as benzene, toluene, xylene, and chlorobenzene, using human epithelial HeLa cells. Thin films based on cysteine-terminated synthetic oligopeptides were fabricated for immobilization of the HeLa cells on a gold (Au) substrate. In addition, an immobilized cell-based sensor was applied to the electrochemical detection of the VOCs. Layer formation and immobilization of the cells were investigated with surface plasmon resonance (SPR), cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS). The adhered living cells were exposed to VOCs; this caused a change in the SPR angle and the VOC-specific electrochemical signal. In addition, VOC toxicity was found to correlate with the degree of nitric oxide (NO) generation and EIS. The primary reason for the marked increase in impedance was the change of aqueous electrolyte composition as a result of cell responses. The p53 and NF-${\kappa}B $ downregulation were closely related to the magnitude of growth inhibition associated with increasing concentrations of each VOC. Therefore, the proposed cell immobilization method, using a self-assembly technique and VOC-specific electrochemical signals, can be applied to construct a cell microarray for onsite VOC monitoring.

• Journal of Korean Society for Atmospheric Environment
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• v.22 no.6
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• pp.929-939
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• 2006

In this study, the concentrations of major odorous compounds including reduced sulfur compounds (DMS, $CS_2$, and DMDS) and aromatic VOC (benzene, toluene, xylene, etc.) were measured continuously using an on-line GC analytical system. Our measurements were made from a residential area of Ansan city during about two weeks period of October, 2004. The highest mean concentrations of reduced S and VOC were recorded as 56.9 ppt of DMS and 21.7 ppb of toluene, respectively. The results of this study generally show that the pollution levels for both types of chemicals are significant relative to previous measurement results reported from comparable sites, if the results are compared simply in terms of the magnitude of the measured concentration data. Moreover, when the relative importance of different compounds is compared in terms of the odor strength, it indicates that the contribution of reduced S compounds may be much more important than that of VOC in the study area.

• The monthly packaging world
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• s.114
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• pp.154-157
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• 2002

• Journal of Korean Society for Atmospheric Environment
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• v.14 no.5
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• pp.507-518
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• 1998

A field comparison study was carried out to quantify differences among various sampling and analytical methods for volatile organic compounds (VOCs) at a site in Vlsan in June 1997. Air sampling containers (SUMMA canisters) were used by the Korea Institute of Science and Technology (KIST) and adsorption tubes (carbotrap) were used by Yeungnam University (YN Univ.) for sampling ambient air. Duplicate samples obtained by KIST were analyzed by KIST with a GC-MS system for aromatics and halogenated hydrocarbons and by Atm AA with a GC -FID system for C2∼C9 hydrocarbons, respectively. The adsorption tube samples were analyzed by YN Univ. with a GC-FID system for aromatics. VOC levels for the duplicate canister sampls analyzed by KIST and Atm AA were in good agreement. Concentrations of aromatics by the adsroption tube method were generally higher than those by the canister sampling method by factor of 1.5 to 2.0. Differences between the two sampling methods were discussed.

• Journal of Sensor Science and Technology
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• v.13 no.6
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• pp.454-461
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• 2004

We have designed a portable electronic nose (e-nose) system using an array of commercial gas sensors and personal digital assistants (PDA) for the recognition and analysis of volatile organic compounds (VOC) in the field. Field screening of pollutants has been a target of instrumental development during the past years. A portable e-nose system was advantageous to localize the special extent of a pollution or to find pollutants source. The employment of PDA improved the user-interface and data transfer by Internet from on-site to remote computer. We adapted the Lavenberg-Marquardt algorithm based on the back-propagation and proposed the method that could predict the concentration levels of VOC gases after classification by separating neural network into two parts.

• Korean Chemical Engineering Research
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• v.51 no.1
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• pp.80-86
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• 2013

In this study, the photocatalytic reactor system equipped with photocatalyst-carrying-silica-media cartridges [photocatalytic reactor system (1)] was used to perform the treatment of waste air containing malodor and volatile organic compound (VOC). The result of its performance was evaluated and compared with that of the photocatalytic reactor system equipped with commercial photocatalyst-carrying-nonwoven filter-media cartridges [photocatalytic reactor system (2)]. In case of photocatalytic reactor system (1), at the 1st stage of run the removal efficiencies of ethanol and toluene continued to be 80% and 20%, respectively. However, unlike toluene, the removal efficiency of ethanol dropped to 40% at the end of the 1st stage of run. The removal efficiency of hydrogen sulfide decreased from 100% to 90%. At the 2nd stage of its run the removal efficiency of ethanol decreased to 10% while the removal efficiencies of hydrogen sulfide and toluene remained as same as 90% and 20%, respectively, even though the inlet load of toluene increased by factor of four. In the 3rd stage of its run, as the result of application of aluminium-coated reflector film to the inner wall of photocatalytic reactor system, the removal efficiencies of ethanol and toluene increased by 5% to be 15% and 25%, respectively. In case of photocatalytic reactor system (2), at the 1st stage of its run, the removal efficiencies of ethanol, hydrogen sulfide and toluene continued to be 10%, 97% and 100%, respectively. However, at 2nd stage of its run their removal efficiencies became 5%, 95% and 2~3%, respectively, which showed that the removal efficiencies of ethanol and hydrogen sulfide decreased insignificantly while the removal efficiency of toluene dropped significantly from the perfect elimination. Moreover, the reflector film did not affect the performance of photocatalytic reactor system (2) at all. Therefore the removal of ethanol, hydrogen sulfide and toluene by photocatalytic reactor system (2) was mainly attributed to hydrophobic adsorption of its nonwoven filter media and its extent of photocatalytic removal turned out to be negligible, compared to that of photocatalytic reactor system (1).

• Journal of Korean Society for Atmospheric Environment
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• v.23 no.6
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• pp.727-733
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• 2007

In this study, a newly developed biotrickling system, combined with a non-thermal plasma reactor, was investigated to effectively treat gaseous contaminants such as VOCs (Volatile Organic Compounds). Three kinds of non-thermal plasmas (NTPs) such as a rod type dielectric barrier discharge (DBD) plasma, a packed bead type DBD plasma and a gliding arc (GA) plasma, were tested and compared in terms of power consumption. The rod type DBD plasma was selected as one for integration with biotrickling system due to its relatively high VOC removal efficiency, low power consumption and low pressure drop. Toluene and xylene as representatives of VOCs were used as test gases. The experiment results showed that the efficiency of biotrickling system was especially very low at the high gas concentration and high flow rate and the removal efficiencies of VOCs were considerably enhanced in the biotrickling system, when the DBD plasma was worked in front of that even at the high gas concentration and high flow rate.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.61.3-61
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• 2001

Field screening for pollutants has been a target of instrumental development for number of years. An electronic nose can be of substantial benefit to rapidly localize the spatial extent of a pollution or to find pollutant source. Although an electronic nose cannot separate complex composition into the whole spectrum of present volatile organic compound(VOC) in pollutants such as Gas chromatography(GC), qualitative and semi-quantitative chemical characterizations are rapidly available on site at a low cost using the optimum sensory system and pattern recognition algorithm based on neural network.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.374.2-374.2
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• 2016

Volatile organic compounds (VOCs) in the atmosphere are harmful materials which influence indoor air environment and human health. Titanium dioxide ($TiO_2$) is photocatalyst extensively used in degradation of organic compound. To improve the photocatalytic activity in the visible light region, doping with non-metals element or loading noble metals on the surface of $TiO_2$ is generally proposed. In this study, N- doped $TiO_2$ having photocatalytic activity in visible light region was attached noble metal such as Pt, Ag, Pd, Au by coupling method. Catalytic activities of Noble metal coupled $N-TiO_2$ powders were evaluated by the improvement of their photocatalytic activities and the degradation of VOC gas. A UV-Vis spectrophotometer was used to measure the diffuse reflectance spectra of coupled $N-TiO_2$ sample. The photocatlytic activities of as prepared samples were characterized by the decoloration of aqueous MB solution under Xenon light source (UV and visible light). To measure of decomposition VOCs, ethylbenzene was selected for target VOC material and the concentration was monitored under UVLED irradiation in a closed chamber system. Adjusting the initial concentration of 10~12 ppm, to evaluate the removal characteristics by using the coupled $N-TiO_2$.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2015.07a
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• pp.316-318
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• 2015

The efficient utilization of VTS console functions in terms of user helps carry out VTS tasks successfully. All the console functions for VTS operation have been surveyed. The default functions used in current VTS console are evaluated by VTS operation, Most popular functions are categorized, and the other functions for the advanced VTS services are suggested. The result of research expect application possibility when designing of GUI.