• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.24 no.1
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• pp.57-63
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• 2011

Dielectric Barrier Discharge (DBD) reactor with sinsodual AC type of power supply is very widely adopted for its compact size and effective discharging mechanism to generate high density of ozone radicals. However, at the aspect of design on power supply, its optimal switching conditions and topology is achieved by empirical test. Therefore, throughout this paper, it is proposed a design method of DBD power supply to guarantee a maximum ozone yield rate in accordance with DBD reactor modification and impedance variation when rapid gas discharging in the DBD reactor is proceeded.

• Journal of the Semiconductor & Display Technology
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• v.9 no.3
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• pp.75-78
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• 2010

In this study we investigated the electrical properties of ZnO-based MOS capacitor with $HfO_2$ as the gate dielectric. MIM capacitor, which uses either $HfO_2$ or $Al_2O_3$ as the dielectric layer, is also studied to understand the dependency of the dielectrics on the preparation conditions. It was found that thinner $HfO_2$ films yield better electrical properties, namely lower leakage current and higher breakdown electric field. These properties were observed to deteriorate when subsequently annealed. Capacitance in the depletion region of MOS capacitor was found to increase with UV ozone treatment time up to 60min. However, when the treatment time was extended to 120min, the trend is reversed. The 'threshold voltage' was also observed to positively shift with UV ozone treatment time up to 60min. The shift apparently saturated for longer treatment.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.14 no.2
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• pp.59-67
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• 2000

In this paper, an ozonizer, which can supply individual and superposed silent discharge using three-phase voltage has been designed and manufactured. The ozonizer consists of 3 electrodes(Central Electrode, Internal Electrode and External Electrode and External electrode) and 2 gaps (gap between Central Electrode and Internal Electrode, gap between Internal Electrode and External Electrode). Ozone is generated according to voltage supplying method to each electrode by individual silent discharge and three-phase superposed discharge. The characteristics of ozone generation were investigated with variation of discharge power and the flow rate of supplied gas (O2). In case of individual silent discharge, the maximum values of ozone concentration, ozone generation and ozone yield were obtained between internal electrode and external electrode, and its values were 2300[ppm], 570[mg/h] and 745[g/kWh] respectively. Each maximum value was 5039[ppm], 1773[mg/h] and 851[g/kWh] respectively, when three-phase superposed silent discharge was employed. Therefore, characteristics of ozone generation with three-phase voltage are improved compared with single-phase voltage because silent discharge is generated continuously.

• Journal of Korean Society of Forest Science
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• v.97 no.5
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• pp.508-515
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• 2008

Sycamore (Platanus occidentalis L.) seedlings were grown under low light intensity and ozone treatments to investigate the role of the light environment in their response to chronic ozone stress. One-year-old seedlings of Platanus occidentalis L. were grown in pots for 3 weeks under low light (OL, $150{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$) and high light (OH, $300{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$) irradiance in combination with 150 ppb of ozone fumigation. After three weeks of ozone and light treatment, seedlings were placed in ozone free clean chamber for 3 weeks for recovery from ozone stress with same light conditions to compare recovery capacity. Ozone fumigation determined an impairment of the photosynthetic process. Reduction of leaf dry weight (14%) and shoo/root ratio (17%) were observed in OH treatment. OL treatment also showed severe reductions in leaf dry weight and shoot/root ratio by 48% and 36% comparing to control, respectively. At the recovery phase, OH-treated plants recovered their biomass, whereas OL-treated plant showed reduction in leaf dry weight (52%) and shoot/root ratio (49%). OH-treated plants reached similar relative growth rate (RGR) comparing to control, whereas OL-treated plants showed lower RGR in stem height. However, there were no significant differences in response to those treatments in stem diameter RGR at the recovery phase. Ozone treatment produced significant reduction of net photosynthesis in both high and low light treatments. Carboxylation efficiency and apparent quantum yield in OL-treated plants showed significant reductions rate to 10% and 45%, respectively. At the recovery stage, ozone exposed seedlings under high light had similar photosynthetic capacity comparing to control plants. Antioxidant enzymes activities such as superoxide dismutase (SOD), ascorbate peroxidase (APX), and glutathione reductase (GR) were increased in ozone fumigated plants only under low light. The present work shows that the physiological changes occur in photosynthesis-related parameters and growth due to ozone and low light stress. Thus, low light seems to enhance the detrimental effects of ozone on growth, photosynthesis, and antioxidant enzyme responses.

• KIEE International Transactions on Electrophysics and Applications
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• v.12C no.4
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• pp.201-207
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• 2002

A Pin-Cylinder discharge type ozonizer was designed and manufactured. The increase or decrease of temperature greatly influences on the characteristics of ozone generation of a discharge type ozonizer. The characteristics of ozone concentration ( $O_{3con}$), ozone generation ($_{3g}$) and ozone yield .ate ($_{3Y}$) of the ozonizer were investigated by varying the gas flow rate (Q), the discharge power ($_{Wd}$ ) and the temperature (T). At T = 20($^{\circ}C$), the values of ( $O_{3con}$) were found as 7800,5300,3000 and 2300(ppm) at Q=1,2,4 and 6(1/min) respectively. The corresponding values of ( $O_{3g}$) were found as 917, l247,1411 and 1623(mg/h) and those of ( $O_{3Y}$) were 93,126,143 and 164(g/kWh) respectively. When the temperature is decreased to -50($^{\circ}C$), the values of ( $O_{3con}$) became 12000,8000,5200 and 3600(ppm) at Q=1,2,4 and 6(1/min) respectively. The corresponding values of 0,9 were obtained as 1411,1882,2446 and 2600(mg/h) and those of ($O_{3Y}$) were 143,190,247 and 2631g/kWh] respectively. Hence as the temperature was decreased from 20 to -50[。C], the efficiencies of ozone generation were increased by 54,51,73 and 60[%] at Q=1,2,4 and 6(1/min) respectively.ctively.

• Proceedings of the Korean Environmental Sciences Society Conference
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• 1998.10a
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• pp.1-1
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• 1998

Advanced (Chemical) oxidation processes (AOP) differ from most conventional ones in that hydroxyl radical(OH.) is considered to be the primary oxidant. Hydroxyl radicalcan react non-selectively with a great number of organic and inorganic chemicals. The typical rate constants of true hydroxyl radical reactions are in the range of between 109 to 1012 sec-1. Many processes are possible to generate hydroxyl radical. These include physical and chemical methods and their combinations. Physical means involves the use of high energy radiation such as gamma ray, electron beam, and acoustic wave. Under an applied high energy radiation, water molecules can be decomposed to yield hydroxyl radicals or aqueous electrons. Chemical means include the use of conventional oxidants such as hydrogen peroxide and ozone, two of the most efficient oxidants in the presence of promoter or catalyst. Hydrogen peroxide in the presence of a catalyst such as divalent iron ions can readily produce hydroxyl radicals. Ozone in the presence of specific chemical species such as OH- or hydrogen peroxide, can also generate hydroxyl radicals. Finally the combination of chemical and physical means can also yield hydroxyl radicals. Hydrogen peroxide in the presence of acoustic wave or ultra violet beam can generate hydroxyl radicals. The principles for hydroxyl radical generation will be discussed. Recent case studied of AOP for water treatment and other environmental of applications will be presented. These include the treatment of contaminated soils using electro-Fenton, lechate treatment with conventional Ponton, treatment of coal for sulfur removal using sonochemical and the treatment of groundwater with enhanced sonochemical processes.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.19 no.5
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• pp.87-93
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• 2005

In order to develope high concentration$\cdot$yield ozonizer, superposed discharge type ozonizer using overlap of silent discharge and internal electrode of mesh type has been designed and manufactured. It consists of three electrodes(central electrode, internal electrode and external electrode) and double gaps(gap between central electrode and internal electrode, gap between internal electrode and external electrode). Therefore, ozone is generated by overlapping silent discharges generated between the gaps respectively for which the AC high voltages applied to the internal electrode and the external electrode has a $180{[^\circ]}$ phase difference and for which the central electrode is a ground Ozone generation characteristics proportional to mesh of internal electrode by increasing of discharge electrode and controlling of discharge power density. As a result, the in maximum ozone concentration, generation, and yield can be obtained 17,720[ppm], 5.4[g/h], and 205[g/kwh] respectively.

• Journal of Marine Bioscience and Biotechnology
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• v.2 no.3
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• pp.149-154
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• 2007

This study was conducted to investigate the effect of ozone treatment on removal of brown color and ammonia-like odor produced from shark cartilage (SC) and to establish the optimal extraction conditions of chondroitin sulfate (CS) by NaOH and hot water. Treatment of SC with 0.3 ppm ozone water resulted in higher color $L^*$ value but lower $a^*$ and $b^*$ values compared with those of non-treated SC, without affecting its proximate compositions (moisture, protein, lipid, carbohydrate, and ash). Ozone treatment also increased the overall acceptability of SC by reducing ammonia-like odor. The optimum concentration and time for extraction of CS from SC using NaOH at $100^{\circ}C$ were 1 N and 120 min, respectively, with 10.02% of extraction yield. The total yield (10.01%) of CS obtained by 7 times repeated extraction with hot water at $100^{\circ}C$ was comparable to that of the 1 N NaOH extraction for 120 min at $100^{\circ}C$.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.48 no.7
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• pp.533-541
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• 1999

Multi-discharge type ozonizer(MDO) using superposed silent discharge has been designed and manufactured. It consists of three electrodes( central electrode, internal electrode, and external electrode ) and double gaps( gap between central electrode and internal electrode, gap between internal electrode and external electrode ). Therefore, ozone is generated by superposing silent discharges generated between the gaps respectively. And the MDO consists of three types of superposed discharge ozonizers according to voltage appling method for each electrode ; A.C. high voltages are applied two of three electrodes with phase difference of 180[˚], the other electrode is a ground. This paper describes that discharge and ozone generation characteristics of MDO which comprising central electrode and internal electrode applied A.C. high voltages with phase difference of 180[˚] respectively, and the grounded external electrode. As a result, the maximum ozone concentration, generation, and yield can be obtained 10208[ppm], 6.4[g/h], and 280[g/kwh] respectively.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.23 no.2
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• pp.118-123
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• 2010

The eco-friendly technologies have been extended as matter of international concern due to various diseases and syndromes according to an environmental pollution. In this study, we have manufactured a ceramic cluster with thick film type for anion generation equipment which is maximized anion but minimized ozone contents generated. To develop the formulation of ceramic cluster, we conducted the $Mg_2SiO_4$ powders doped with 10 vol% glass frits as Na-Zn-B-O system and sintered at $1050^{\circ}C$ for 2 hours in air for starting materials and investigated the matching properties between the Ag-Pd electrode and the starting materials. The sintered sample for the composition of cluster has 6.7 of dielectric constant and 32 kV/mm of withstand voltage. The yield of anions was measured according to an electrode pattering, discharge gap between electrode, and thickness of electrode protective layer in the cluster of thick film type. We have manufactured the ceramic clusters with optimized thick film structure that have an anion over a hundred particles and the ozone of 0.6 ppb generated.