• Korean Chemical Engineering Research
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• v.45 no.5
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• pp.455-459
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• 2007

Plasma catalytic methane conversion was carried out in the presence of sol-gel derived $Pt/TiO_2$ catalysts within a dielectric-barrier discharge (DBD) reactor. Plasma-assisted reduction (PAR) was applied to reduce the prepared $Pt/TiO_2$ catalysts in DBD reactor, and prepared catalysts were successively reduced by PAR within 20 min irrespective of the Pt loading and the calcination temperature. The highest methane conversion was 40% when 3 wt% $Pt/TiO_2$ and 5 wt% $Pt/TiO_2$ catalysts were used after calcination at $600^{\circ}C$. The selectivities of light alkanes ($C_2H_6$, $C_3H_8$, $C_4H_{10}$) were highly increased when $Pt/TiO_2$ catalysts were used in DBD reactor.

• KSBB Journal
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• v.30 no.1
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• pp.21-26
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• 2015

Plasma is an ionized gas mixture, consisting of neutral particles, positive ions, negative electrons, electronically excited atoms and molecules, radicals, UV photons, and various reactive species. Also, plasma has unique physical properties distinct from gases, liquids, and solids. Until now, non-thermal plasmas have been widely utilized in bio-medical applications (called bio-plasma) and have been developed for the plasma-related devices that are used in the medical field. Although numerous bio-plasma studies have been performed in biomedicine, there is no confirmation of the nonthermal effect induced by bio-plasma. Standardization of the biological application of plasma has not been evaluated at the molecular level in living cells. In this context, we investigated the biological effect of bio-plasma on living cells. Hence, we treated the fibroblasts with Dielectric Bauvier Discharge bio-plasma (DBD), and assessed the characteristic change at the molecular level, one of the typical cellular responses. Heat shock protein 70 (HSP70) regulates its own protein level in response to stimuli. HSP70 responds to heat shock by increasing its own expression at the molecular level in cells. Hence, we confirmed the level of HSP70 after treatment of mouse embryonic fibroblasts (MEFs) with DBD. Interestingly, DBD-plasma induced cell death, but there was no difference in the level of HSP70, which is induced by heat shock stimuli, in DBD-treated MEFs. Our data provide the basic information on the interaction between MEFs and DBD, and can help to design a molecular approach in this field.

• Molecules and Cells
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• v.37 no.3
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• pp.264-269
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• 2014

The molecular interaction between tumor suppressor p53 and the anti-apoptotic Bcl-2 family proteins plays an essential role in the transcription-independent apoptotic pathway of p53. In this study, we investigated the binding of p53 DNA-binding domain (p53DBD) with the anti-apoptotic Bcl-2 family proteins, Bcl-w, Mcl-1, and Bcl-2, using GST pull-down assay and NMR spectroscopy. The GST pull-down assays and NMR experiments demonstrated the direct binding of the p53DBD with Bcl-w, Mcl-1, and Bcl-2. Further, NMR chemical shift perturbation data showed that Bcl-w and Mcl-1 bind to the positively charged DNA-binding surface of p53DBD. Noticeably, the refined structural models of the complexes between p53DBD and Bcl-w, Mcl-1, and Bcl-2 showed that the binding mode of p53DBD is highly conserved among the anti-apoptotic Bcl-2 family proteins. Furthermore, the chemical shift perturbations on Bcl-w, Mcl-1, and Bcl-2 induced by p53DBD binding occurred not only at the p53DBD-binding acidic region but also at the BH3 peptide-binding pocket, which suggests an allosteric conformational change similar to that observed in Bcl-$X_L$. Taken altogether, our results revealed a structural basis for a conserved binding mechanism between p53DBD and the anti-apoptotic Bcl-2 family proteins, which shed light on to the molecular understanding of the transcription-independent apoptosis pathway of p53.

• Korean Journal of Culture and Social Issue
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• v.17 no.2
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• pp.175-197
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• 2011

This study aimed to expand and reconstruct the Driving Behavior Determinants' factors in order to confirm the relationship between Driving Behavior Determinants(DBD) and drivers' reckless driving behavior level. To expand the structure of DBD, drivers anger, introversion and type A characteristics were added, which were never considered as related factors in existing DBD studies before. The correlations between the new factors of DBD and reckless driving behavior(includes driver's personal records of driving experiences for the last three years) were verified. A factor analysis result showed us that new DBD questionnaire consists of five factors such as, 'Problem Evading', 'Benefits/Sensation Seeking', 'Anti-personal Anxiety', 'Anti-personal Anger', and 'Aggression'. Also, reckless driving behavior consists of 'Speeding', 'Inexperienced Coping', 'Wild Driving', 'Drunken Driving', and 'Distraction'. The result of correlation between the DBD and reckless driving behavior indicates that inappropriate level of DBD is highly correlated with dangerous driving behavior and strong possibilities of traffic accidents. Based on these results, we might be able to discriminate drivers according to DBD level and predict their reckless driving behavior through a standardization procedure. Futhermore, this will make us to provide drivers differentiated safety education service.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2008.06a
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• pp.597-598
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• 2008

• Bulletin of the Korean Chemical Society
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• v.34 no.4
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• pp.1300-1302
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• 2013

• Journal of Korean Society of Environmental Engineers
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• v.27 no.2
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• pp.215-223
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• 2005

Non-thermal plasma decomposition of gas-phase styrene was investigated in this study using three different types of plasma reactors; dielectric-barrier discharge (DBD) reactor, surface discharge (SD) reactor and plasma-driven catalyst (PDC) reactor packed with 2.0 wt% $Ag/TiO_2$ catalysts. The main parameters used for the comparative assessment of the plasma reactors include the decomposition efficiency, carbon balance, byproduct distribution, COx ($CO+CO_2$) selectivity and COx yield. The SD and the DBD reactors showed better conversion efficiency of styrene than that of the PDC reactor due to their larger capability in ozone formation. On the other hand, the PDC reactor showed better carbon balance, the yield and the selectivity of COx. The required specific input energies to achieve 100% carbon balance from the decomposition of 100 ppmv styrene using the plasma alone reactors and the PDC reactor were 420 J/L and 110 J/L, respectively. The major decomposition products in gas-phase were CO, $CO_2$ and HCOOH regardless of the types of plasma reactors. In the case of SD and DBD reactors, the $CO_2$ selectivity ranged in $39.5{\sim}60%$. The $CO_2$ selectivity in the PDC reactor was in range of $68.5{\sim}75.5%$.

• Journal of the Society of Disaster Information
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• v.19 no.2
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• pp.344-351
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• 2023

Purpose: This study aimed to evaluate the effectiveness of a dielectric barrier discharge (DBD) plasma module for sterilizing airborne bacteria in indoor spaces and measure the concentration of ozone generated during plasma discharge. Method: The DBD plasma module was installed in a 76m³ space, and air samples were collected under various discharge times to compare the reduction of airborne bacteria. Result: The results showed a significant decrease in airborne bacteria, ranging from 92.057% to 99.999%, with an average ozone concentration of 0.04 ppm, below the reference value. Conclusion: The study suggests that plasma discharge can be used as a means of preventing the spread of airborne bacteria and viruses, while ensuring safety for human exposure.

• Korean Journal of Environmental Biology
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• v.40 no.4
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• pp.641-650
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• 2022

The purpose of this study was to compare the efficiency of air and oxygen injected into the underwater non-thermal dielectric barrier discharge plasma (DBD plasma) device used to remove five types of antibiotics (tetracycline, doxycycline, oxytetracycline, clindamycin, and erythromycin) artificially contained in the fish farm discharge water. The voltage given to generate DBD plasma was 27.8 kV, and the measurement intervals were 0, 0.5, 1, 2, 4, 8, 16 and 32 minutes. Tetracycline antibiotics significantly decreased in 4 minutes when air was injected and were reduced in 30 seconds when oxygen was injected. After the introduction of air and oxygen at 32 minutes, 78.1% and 95.8% of tetracycline were removed, 77.1% and 96.3% of doxycycline were removed, and 77.1% and 95.5% of oxytetracycline were removed, respectively. In air and oxygen, 59.6% and 83.0% of clindamycin and 53.3% and 74.3% of erythromycin were removed, respectively. The two antibiotics showed lower removal efficiency than tetracyclines. In conclusion, fish farm discharge water contains five different types of antibiotics that can be reduced using underwater DBD plasma, and oxygen gas injection outperformed air in terms of removal efficiency.

• The KSFM Journal of Fluid Machinery
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• v.15 no.3
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• pp.46-50
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• 2012

Plasma actuator makes parallel flow on the wall surface by the interaction between plasma and neutral air particles. Dielectric barrier discharge (DBD) plasma actuator is widely studied as one type of plasma actuators, which consists of one electrode exposed to the environmental gas and the other encapsulated by a dielectric material. This paper is experimentally focused on the performance of DBD plasma actuator mounted on a flat plate, which depends on kinds of the electrode materials, their thicknesses and the supplied voltage including its frequency. We measured the velocity magnitudes of the induced flow by a stagnation probe as a performance parameter of the plasma actuators. The velocity profiles of the flow induced by the plasma actuators are similar in all measurement cases. The magnitude of the induced velocity is strongly influenced by the thickness of the electrodes and the frequency of the input voltage. The performance of DBD plasma actuators is related to the electric properties of the electrode materials such as the ionization energy and the electrical resistivity.