• Title/Summary/Keyword: Ozone density

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Voltage Source Resonant Inverter for Excimer Gas Discharge Load

  • Koudriavtsev Oleg;Nakaoka Mutsuo
    • Proceedings of the KIPE Conference
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    • 2001.10a
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    • pp.89-92
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    • 2001
  • Silent gas discharge method has been widely applied for ozone production, ultraviolet light and UV laser generation. Since ozone and ultraviolet applications have tendency to spread widely in industry, the development of efficient and low-cost power supply for such systems is a task of great impotency. This paper introduces high-frequency inverter type mode power supply designed for ozone generation tube and ultraviolet generation excimer lamp and considerations on this inverter and pulse density modulation control strategy applied in it.

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Voltage Source Resonant Inverter for Excimer Gas Discharge Load

  • Koudriavtsev, Oleg;Nakaoka, Mutsuo
    • Journal of Power Electronics
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    • v.2 no.3
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    • pp.206-211
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    • 2002
  • Silent gas discharge method has been widely applied fur ozone production, ultraviolet light and UV laser generation. Since ozone and ultraviolet applications have tendency to spread widely in industry, the development of efficient and low - cost power supply for such systems is an important task at present. This paper introduces high-frequency inverter type mode power supply designed fur ozone generation tube and ultraviolet generation excimer lamp and considerations on the design of the inverter and pulse density modulation control strategy applied in it.

The Effects of Electrodeposited Lead Dioxide Structure on the Ozone Evolution (전착이산화납 결정구조가 전해에 의한 오존발생에 미치는 영향)

  • Kim, In Hwan;Lee, Choong Young;Nam, Chong Woo
    • Applied Chemistry for Engineering
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    • v.7 no.2
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    • pp.280-288
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    • 1996
  • In the ozone evolution using $PbO_2$, which was electrodeposited on Ti plate at various conditions in electrolyte, the effects of lead dioxide structure on the current efficiency and surface structure changes of lead dioxide were investigated. Also the effects of oxygen transfer reaction on the ozone evolution were investigated by means of a $PbO_2$ electrodeposited on the platinum rotating disk electrode. In order to develope an electrode for ozone evolution, durability of lead dioxide and optimum current density were investigated. At the electrodeposited lead dioxide with the larger grain size and higher crystallinity, the efficiency for ozone evolution was higher. Optimum current density to electrodeposite lead dioxide with large grain size and high crystalinity was $50mA/cm^2$. Lead dioxide deposited in the presence of glycerin showed the best advantage of ozone evolution. Also lead dioxide electrodeposited at less than $10mA/cm^2$ or at more than $100mA/cm^2$ has poor performance of ozone evolution and poor adhesive strength to substrate. In the beginning of ozone evolution, surface structure of lead dioxide was changed and this change resulted in good effects on ozone evolution. Lead dioxide doped with other elements was favorable not to ozone evolution but to oxygen evolution, so it is speculated that ozone evolution has not intermediate stage of oxygen evolution and occurs competitively with oxygen evolution. When ozone was evolved at $0.7{\sim}0.8A/cm^2$, the current efficiency was highest.

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Improvement of Market Quality of Minimally Processed Horticultural Products Using Ozone (오존수를 활용한 부분 가공 원예산물의 청정화 및 유통성 증진)

  • Hwang, Yong Soo;Jun, Il Yeul;Ku, Ja Hyeung
    • Korean Journal of Agricultural Science
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    • v.30 no.2
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    • pp.128-138
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    • 2003
  • The bacterial density of partially processed horticultural crops in the commercial market was relatively high probably due to improper handing or processing. Between crops, the bacterial density was low in peeled garlic and ranged above $10^8cfu{\cdot}g^{-1}fw$ in other crops. Especially in brake fern, the bacterial density was the highest and non food materials such as packing strips were found. There was difference in the effects of ozone-treated water washing treatment between crops. In root crops such as burdock and lotus root, ozone showed positive effect on preventing discoloration as well as lowing bacterial density resulting in the increase of marketing period. Any positive effect was not found when sliced crops were treated over 5 min at $0.3mg{\cdot}L^{-1}$ of dissolved ozone. In lettuce slices, leaf tissues were severely discolored and rapidly soften at $0.3mg{\cdot}L^{-1}$ for 2 min dipping. Ozone was highly effective on inhibiting bacterium propagation and off-flavor. This effect was more stronger in Fischer ligulariata than brake fern, probably due to the difference of tissue thickness. Results indicated that ozone-treated water washing had a strong potential to improve the market quality of partially processed horticultural crops including dried wild greens and sliced root crops.

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The Variations of Stratospheric Ozone over the Korean Peninsula 1985~2009 (한반도 상공의 오존층 변화 1985~2009)

  • Park, Sang Seo;Kim, Jhoon;Cho, Nayeong;Lee, Yun Gon;Cho, Hi Ku
    • Atmosphere
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    • v.21 no.4
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    • pp.349-359
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    • 2011
  • The climatology in stratospheric ozone over the Korean Peninsula, presented in previous studies (e.g., Cho et al., 2003; Kim et al., 2005), is updated by using daily and monthly data from satellite and ground-based data through December 2009. In addition, long-term satellite data [Total Ozone Mapping Spectrometer (TOMS), Ozone Monitoring Instrument (OMI), 1979~2009] have been also analyzed in order to deduce the spatial distributions and temporal variations of the global total ozone. The global average of total ozone (1979~2009) is 298 DU which shows a minimum of about 244 DU in equatorial latitudes and increases poleward in both hemispheres to a maximum of about 391 DU in Okhotsk region. The recent period, from 2006 to 2009, shows reduction in total ozone by 6% relative to the values for the pre-1980s (1979~1982). The long-term trends were estimated by using a multiple linear regression model (e.g., WMO, 1999; Cho et al., 2003) including explanatory variables for the seasonal variation, Quasi-Biennial Oscillation (QBO) and solar cycle over three different time intervals: a whole interval from 1979 to 2009, the former interval from 1979 to 1992, and the later interval from 1993 to 2009 with a turnaround point of deep minimum in 1993 is related to the effect of Mt. Pinatubo eruption. The global trend shows -0.93% $decade^{-1}$ for the whole interval, whereas the former and the later interval trends amount to -2.59% $decade^{-1}$ and +0.95% $decade^{-1}$, respectively. Therefore, the long-term total ozone variations indicate that there are positive trends showing a recovery sign of the ozone layer in both North/South hemispheres since around 1993. Annual mean total ozone (1985~2009) is distributed from 298 DU for Jeju ($33.52^{\circ}N$) to 352 DU for Unggi ($42.32^{\circ}N$) in almost zonally symmetric pattern over the Korean Peninsula, with the latitudinal gradient of 6 DU $degree^{-1}$. It is apparent that seasonal variability of total ozone increases from Jeju toward Unggi. The annual mean total ozone for Seoul shows 323 DU, with the maximum of 359 DU in March and the minimum of 291 DU in October. It is found that the day to day variability in total ozone exhibits annual mean of 5.7% in increase and -5.2% in decrease. The variability as large as 38.4% in increase and 30.3% in decrease has been observed, respectively. The long-term trend analysis (e.g., WMO, 1999) of monthly total ozone data (1985~2009) merged by satellite and ground-based measurements over the Korean Peninsula shows increase of 1.27% $decade^{-1}$ to 0.80% $decade^{-1}$ from Jeju to Unggi, respectively, showing systematic decrease of the trend magnitude with latitude. This study also presents a new analysis of ozone density and trends in the vertical distribution of ozone for Seoul with data up to the end of 2009. The mean vertical distributions of ozone show that the maximum value of the ozone density is 16.5 DU $km^{-1}$ in the middle stratospheric layer between 24 km and 28 km. About 90.0% and 71.5% of total ozone are found in the troposphere and in the stratosphere between 15 and 33 km, respectively. The trend analysis reconfirms the previous results of significant positive ozone trend, of up to 5% $decade^{-1}$, in the troposphere and the lower stratosphere (0~24 km), with negative trend, of up to -5% $decade^{-1}$, in the stratosphere (24~38 km). In addition, the Umkehr data show a positive trend of about 3% $decade^{-1}$ in the upper stratosphere (38~48 km).

VERTICAL OZONE DENSITY PROFILING BY UV RADIOMETER ONBOARD KSR-III

  • Hwang Seung-Hyun;Kim Jhoon;Lee Soo-Jin;Kim Kwang-Soo;Ji Ki-Man;Shin Myung-Ho;Chung Eui-Seung
    • Bulletin of the Korean Space Science Society
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    • 2004.10b
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    • pp.372-375
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    • 2004
  • The UV radiometer payload was launched successfully from the west coastal area of Korea Peninsula aboard KSR-III on 28, Nov 2002. KSR-III was the Korean third generation sounding rocket and was developed as intermediate step to larger space launch vehicle with liquid propulsion engine system. UV radiometer onboard KSR-III consists of UV and visible band optical phototubes to measure the direct solar attenuation during rocket ascending phase. For UV detection, 4 channel of sensors were installed in electronics payload section and each channel has 255, 290, 310nm center wavelengths, respectively. 450nm channel was used as reference for correction of the rocket attitude during the flight. Transmission characteristics of all channels were calibrated precisely prior to the flight test at the Optical Lab. in KARI (Korea Aerospace Research Institute). During a total of 231s flight time, the onboard data telemetered to the ground station in real time. The ozone column density was calculated by this telemetry raw data. From the calculated column density, the vertical ozone profile over Korea Peninsula was obtained with sensor calibration data. Our results had reasonable agreements compared with various observations such as ground Umkhr measurement at Yonsei site, ozonesonde at Pohang site, and satellite measurements of HALOE and POAM. The sensitivity analysis of retrieval algorithm for parameters was performed and it was provided that significant error sources of the retrieval algorithm.

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Effects of Operating Parameters on Ozone Production by Plasma Gun for Ballast Water Treatment (밸러스트 수 처리를 위한 Plasma Gun의 오존생성에 미치는 운전변수의 영향)

  • Lee, Hyeon-Don;Kim, Jong-Oh;Chung, Jae-Woo
    • Journal of Navigation and Port Research
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    • v.34 no.3
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    • pp.205-211
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    • 2010
  • Effects of operating parameters on electrical properties and ozone generation of Plasma Gun for ballast water treatment were investigated in a laboratory scale experiment. Electrical discharges and ozone generation initiated with applying voltages higher than discharge onset value. Ozone concentration was almost linearly increased with the increase of applied voltage. The optimum electrode gap distance which gave the optimum energy efficiency of ozone generation was 1.95 mm in the experimented apparatus. The effect of inner electrode material on the electrical energy transfer was negligible, however, the difference of electrical and thermal conductivities between electrode materials significantly influenced the ozone generation. In a constant geometrical structure, the electrical energy density played an important role in the ozone generation. The increase of oxygen content in the feeding gas enhanced the ozone generation by lowering ionization potential and promoting ozone source.

Development of Activated Graphite Felt Electrode Using Ozone and Ammonia Consecutive Post Treatments for Vanadium Redox Flow Batteries (오존, 암모니아 순차적 처리를 통한 바나듐 레독스 흐름 전지용 활성화 카본 펠트 전극 개발)

  • CHOI, HANSOL;KIM, HANSUNG
    • Transactions of the Korean hydrogen and new energy society
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    • v.32 no.4
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    • pp.256-262
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    • 2021
  • A carbon felt electrode was prepared using ozone and ammonia sequential treatment and applied as an electrode for a vanadium redox flow battery (VRFB). The physical and electrochemical analyses demonstrate that the oxygen groups facilitate nitrogen doping in the carbon felt. Carbon felt (J5O3+NH3), which was subjected to ammonia heat treatment after ozone treatment, showed higher oxygen and nitrogen contents than carbon felt (J5NH3+O3), which was subjected to ammonia heat treatment first and then ozone treatment. From the charging/discharging of VRFB, the J5O3+NH3 carbon felt electrode showed 14.4 Ah/L discharge capacity at a current density of 150 mA /cm2, which was 15% and 33% higher than that of J5NH3+O3 and non-activated carbon felt (J5), respectively. These results show that ozone and ammonia sequential treatment is an effective carbon felt activation method to increase the performance of the vanadium redox flow battery.

Fundamental Investigation Results on Ozone Generation Characteristics by Superimposed Discharge (중첩방전에 의한 오존생성 특성)

  • ;Chobei YAMABE
    • The Transactions of the Korean Institute of Electrical Engineers C
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    • v.52 no.2
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    • pp.91-97
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    • 2003
  • In addition to its strong oxidizing power, the ozone has definite advantages over other commercial oxidants, namely, no undesirable by- products or residues are formed. With growing interest in the improvement of the ozone production in the industrial fields, many types of ozonizer using the electrical discharges have been proposed for the higher efficiency and the higher Performance at atmospheric Pressure. Among them, a superposition of different type discharges has been proposed. Especially, since the improvement for the low efficiency of dc discharge and narrow gap of surface discharge is required, a do and an at voltage are applied to same reaction space (or volume) to increase energy density at the same space. An investigation was focused on the superposition with a dc (streamer) corona and 3 surface discharge. This paper describes the investigation results on fundamental ozone generation characteristics by this superimposed discharge.

Study of Electrolysis Ozone Generator Using Polymer Electrolyte (고분자 전해질을 이용한 전기분해식 오존 발생에 관한 연구)

  • Park, Jong-Eun;Lee, Ju-Bong;Lee, Hong-Ki;Park, Soo-Gil
    • Proceedings of the KIEE Conference
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    • 1999.11d
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    • pp.906-908
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    • 1999
  • The application of ozone solid polymer electrolyte or Membrel water electrolysis cells with $PbO_2$ anodes for anodic generation of ozone in electrolyte-free water is reported. Maximum yields were obtained at a temperature of $25^{\circ}C-30^{\circ}C$ and current density of about 1A/$cm^2$. The current efficiency was not found to depend on ozone concentration in the feed water. exclusive transference of electric current by protons absence of convection in the electrolyte and high oxygen oversaturatation in the vicinity of electrode

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