• Journal of Korean Society for Atmospheric Environment
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• v.20 no.3
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• pp.345-360
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• 2004

The late sea-breeze and its impacts on ozone distributions were investigated during April to September from 1998 to 2002, in the Busan metropolitan area (including surrounding areas) using the surface ozone concentrations (obtained at 9 monitoring sites), local meteorological variables (obtained near the shore), together with synoptic data. The urban scale ozone concentration was also simulated using the MM5/UAM-V to better understand the role of late sea-breeze in Busan. The results from observation study showed that most of the late sea-breeze occurred when weak offshore synoptic flow (northwesterly) suppressed development of sea - breeze, and the ozone concentration level and frequencies exceeding ozone standard increased with the onset time of sea breeze. We also found that the late sea-breeze clearly induces relatively weak wind speed and high temperature during the daytime As a result it enhances the photochemical ozone accumulation and delays the occurrence time of the averaged maximum ozone concentrations. The results of simulation for high ozone episode (24 August, 2001) by MM5/UAM -V revealed that the late sea-breeze interacted with weak offshore synoptic wind can contribute significantly to high ozone concentration in the coastal urban area. The simulated horizontal and vertical distribution of ozone concentration indicated that ozone can be accumulated over the sea under stagnant condition and return to the land in the late afternoon with the sea breeze, suggesting both the relationship between late sea-breeze and recirculation and the importance of late sea -breeze effects influencing severe ozone pollution in Busan.

• Journal of Environmental Science International
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• v.12 no.4
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• pp.419-426
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• 2003

This study was performed to research ozone concentration related to airmass thunderstorm using 12 years meteorological data(1990~2001) at Busan. The occurrence frequency of thunderstorm during 12 years was 156 days(annual mean 13days). The airmass thunderstorm frequency was 14 days, most of those occurrence at summertime(59%). In case August 4, 1996, increase of ozone concentration was simultaneous with the decrease of temperature and increase of relative humidity, In case July 23, 1997, ozone concentration of western site at Busan increased, while its of eastern site decreased as airmass thunderstorm occurred(about 1500LST). It is supposed that these ozone increases are the effect of ozone rich air that is brought down by cumulus downdrafts from height levels where the ozone mixing ratio is larger. Thunderstorms can cause downward transport of ozone from the reservoir layer in the upper troposphere into planeta교 boundary layer(PBL). This complex interaction of source and sink processes can result in large variability fer vertical and horizontal ozone distributions. Thus a variety of meteorological precesses can act to enhance vertical mixing between the earth's surface and the atmospheric in the manner described fer thunderstorm.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.50 no.4
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• pp.169-175
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• 2001

Ozone has been widely applied to many industrial fields because of its strong oxidation power, Therefore, the studies have been carried out for the methods on an effective and high concentration ozone generation. The silent or surface discharge type ozone generators have been mainly used for high concentration ozone generation in many fields of applications. But these two types of ozone generators have shortcomings to be improved. In this study, the ozone generator which improved the shortcomings of above ozone generators was proposed and fabricated for the high concentration ozone generation. And the proposed ozone generator could generate the surface and barrier discharge simultaneously. For this purpose, a mesh type discharge electrode was proposed and studied as a function of the widths output maximum ozone concentration of 2.96[vol%] was obtained at 5.6[kV], 830[mA], for 0.3[mm] width and 0.8[mm] vacancy of the mesh electrode and gap spacing of 0.65[mm] respectively.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.05d
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• pp.25-28
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• 2003

Ozone is a strong and useful oxidizing gas for the fabrication of oxide thin films. In order to obtain high quality oxide thin films, higher ozone concentration is necessary. In this paper an ozone condensation system was evaluated from the viewpoint of an ozone supplier for oxide thin film growth. Ozone was condensed by an adsorption method and the ozone concentration reached 8.5 mol% in 2.5 h after the beginning of the ozone condensation process, indicating high effectiveness of the condensation process. Ozone was continuously desorbed from the silica gel by the negative pressure. We found the decomposition in the ozone concentration negligible if the condensed ozone is transferred from the ozone condensation system to the film growth chamber within a few minutes.

• Journal of Korean Society for Atmospheric Environment
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• v.5 no.2
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• pp.55-71
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• 1989

This study was carried out to determine the ozone concentration to behaviour and the factors to be influenced the variation of its concentration in the ambient air in Seoul. Measurements of ozone concentrations were made at 10 monitoring station to take care of SIHE (Seoul Institute of Health & Environment) during December 1987 to November 1988, also measured the hourly average concentration of sulfur dioxide, total suspended particulate, nitrogen oxide $(NO & NO_2)$, carbon monoxide, hydro carbon $(n-CH_4 & THC)$ and meteorological factors, that is, temperature, humidity, wind velocity wind direction and ultraviolet intensity etc, for the same period at same place. The basis of the data obtained were analyzed statistically along with the various data. The results were as follows; 1. The annually arithmetic mean concentration of ozone for the 10 sites during one years was 10.0 ppb and ranged from 3.1 $\pm$ 4.5ppb at the Kuro industrial complex to 17.2 $\pm$ 18.7 ppb at the Ssangmun site. 2. The frequency of hours on which oxidant concentrations exceeded the present short term standard of ozone (100 ppb) were 78 times. 3. The diurnal patterns of hourly ozone concentrations in Seoul area was a typical bi-modal variation which have 4 to 5 a.m. peak and 3. to 4 p.m peak. 4. The time ozone of highest ozone concentration in a whole day and hight was 1 to 5 p.m and 90.9 percent of appearence rate. 5. The diurnal patterns of hourly ozone concentrations in Seoul were on the whole the order of daytime from 5.8ppb to 28.7 ppb evening from 1.7 to 18.7 ppb night time from 1.9 to 9.3 ppb daybreak from 1.4ppb according to measuring sites, and the highest that observed at the Ssangmun area while the lowest was the Kuro industrial complex monitor sites. 6. The weekly variation of ozone concentration was the higher level ozone concentration in the day of the week occured sunday-monday and weekend but the decrease were observed from wednesday to thursday.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.52 no.12
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• pp.579-585
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• 2003

Recently the utilization of the ozone dissolved de-ionized water(DI-O3 water) in semiconductor wet cleaning process to replace the conventional RCA methods has been studied. In this paper, we propose the water-electrode type ozone generator which has the ozone gas characteristics of the high concentration and high purity to produce the high concentration DI-O3 water for the silicon wafer surface cleaning process. The ozone generator has the dual dielectric tube structure of silent discharge type and the water is both used to electrode and cooling water. We investigate the performance of the proposed ozone generator which has the design goal of the concentration of 7[wt%] and ozone generation quantity of 6[g/hr] at flow rate of 1[$\ell$/min). The experiment results show that the water electrode type ozone generator has the characteristics of 8.48[wt%] of concentration, 8.08[g/hr] of generation quantity and 76.2[g/kWh] of yield and it's possible to use the proposed ozone generator for the DI-O3 water cleaning process of silicon wafer surface.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.11a
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• pp.331-332
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• 2005

Ozone is ambient gas which is useful for the fabrication of metal oxide thin films under conditions of molecular beam epitaxy. Ozone is condensed by the adsorption method and its concentration is analyzed using the thermal decomposition method. The concentration of ozone exceeds 90 mol% and ozone is supplied for a sufficiently long time to grow oxide thin films. The ozone concentration is also evaluated using a quadrupole mass analyzer and the accuracy of this method is compared with the results of the thermal decomposition method.

• Journal of Environmental Science International
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• v.19 no.6
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• pp.761-769
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• 2010

Temporal trends of ozone concentration in Jinju were investigated by using observation data from 3 air quality monitoring stations for the period of 2004~2008. In addition, spatial comparisons of ozone concentration at Jeoguri, upwind and downwind directions of Jinju were investigated between May and September 2009. Annual mean exhibited increasing trends +1.7ppb/yr throughout the study period. In the case of diurnal variation, the lowest ozone concentration was shown from 7 am to 8 am and the highest around 4 pm. The ozone concentrations of Jeoguri station of the south coast were higher than Jinju. In particular, the upwind direction of Jinju had relatively hight ozone concentration

• Journal of Environmental Science International
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• v.16 no.8
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• pp.985-994
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• 2007

To investigate the effect of NOx and VOCs(volatile organic compounds) on the generation of high ozone episode, examined the hourly variations of ozone, NOx and VOCs concentrations, and calculated the ozone isopleth about maximum ozone concentrations using OZIPR which was presented by U. S. EPA at three sites in Busan. There was some difference by the sites, but decreasing VOCs concentration was effective for reduction of ozone at 22 July, the episode day of 2005. In the year 2006, the episode day was 8 August and the variations of NOx and VOCs concentration was little than variation of ozone. So it was estimated that the photochemical production of ozone was low than transportation of ozone. And the result of the OZIPR modeling was that decreasing VOCs concentration was effective for reduction of ozone.

• Journal of Korean Society for Atmospheric Environment
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• v.15 no.6
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• pp.747-755
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• 1999

Effects of precipitation and cloud cover on high ozone days are examined by investigating the precipitation and average cloud cover before the ozone peak time within a day. High ozone days above 100 ppb in the Greater Seoul Area(GSA) for the ozone season from May to September are chosen for the analyses in terms of the surface meteorological data during 1990~1997. The result shows that the effect of precipitation on the rise of ozone concentration is definitely negative so that ozone concentration could not rise above 100ppb immediately after precipitation. But, the effect of cloud cover is associated with the variations of other meteorological parameters. The number of high ozone days with "zero" cloud cover is rather less than that with cloud cover of 1 to 4 since temperature is usually lower in "zero" cloud cover days. Furthermore, ozone concentration can rise above 100ppb even with full cloud cover when the wind is weak and the temperature is high.temperature is high.