• Journal of the Korean earth science society
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• v.23 no.5
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• pp.424-435
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• 2002

This study analyzes the surface ozone and meteorological data in Daegu for a period from 1997 to 1999. It also investigates the meteorological characteristics of high ozone episodes. For this study the high ozone episode has been defined as a daily maximum ozone concentration higher than 100ppb in at least one station among six air quality monitoring stations in Daegu, Korea. The frequency of episodes is 13 days. The frequency is the highest in May and September. The average value of daily maximum ozone concentration is 81.6ppb, and 8-hour average ozone concentration is 58.6ppb for the high episodes. This shows that ozone pollution is continuous and wide-ranging in Daegu. The daily maximum ozone concentration is positively correlated to solar radiation and daily maximum temperature, but negatively correlated to relative humidity, wind speed and cloud amount. The maximal correlation coefficient to solar radiation is 0.45. The differences between high ozone episode day's daily mean meteorological value and monthly mean value are +1.58hPa for sea level pressure, +3.45${\circ}$C for maximum temperature, -5.69% for relative humidity, -0.46ms$^{-1}$ for wind speed, -1.79 for cloud amount, and +3.97MJm$^{-2}$ for solar radiation, respectively. This shows that strong solar radiation, low wind speed and no precipitation between 0700${\sim}$1100LST are favorite conditions for high ozone episodes. It is related to the morning stagnant condition.

• Journal of Korean Society on Water Environment
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• v.29 no.1
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• pp.74-80
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• 2013

The aim of this study is to evaluate color removal from leather-dyeing wastewater using $O_3$ and $O_3/H_2O_2$ unit processes and a serial process for $O_3$, followed by the $O_3/H_2O_2$ process. The color removal rate of the $O_3$ alone process was only 65% effective, and the color increased when an applied $O_3$ dose of more than 40 ~ 50 mg/L was applied. On the other hand, the color was completely removed without increments of color by the $O_3/H_2O_2$ process with $H_2O_2$ injection ratio of 0.2 and 0.3 (wt. $H_2O_2$/wt. $O_3$). Even though the injection of $H_2O_2$ had an effect on color removal, the color removal rates from $O_3$ alone and from $O_3/H_2O_2$ were similar up to the initial $O_3$-demand stage with an application of 0 ~ 40 mg/L $O_3$. In conclusion, it was found that the $O_3$ followed by the $O_3/H_2O_2$ serial process, the method injecting $H_2O_2$ after ozonation with $O_3$-demand (30 ~ 40 mg/L) in the first stage, is the most appropriate process for effective color removal from leather-dyeing wastewater.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2003.11a
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• pp.295-296
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• 2003

1990년대 이후 활발히 진행되고 있는 국내 $O_3$ 연구는 대부분 서울 지역에 국한되어 있다. 그러나 대도시의 $O_3$ 농도가 대도시 내에서의 생성 및 소멸에만 기인하는 것이 아니라 대기 운동과 관련된 수평 및 연직 수송에 의한 영향도 중요한 요소임이 많은 연구에서 밝혀지고 있다. 따라서 청정 대기 상태에서 $O_3$의 배경 농도 특성에 대한 연구의 필요성이 증가하고 있다 (서명석 등, 1995). 울릉도 태하는 우리나라의 배경 농도 지역으로 청정 대기 상태에서의 $O_3$ 농도 특성을 연구하기 좋은 지역이다. (중략)

• Korean Journal Plant Pathology
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• v.11 no.2
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• pp.107-115
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• 1995

들깨 '수원25호', 담배 'L8', 'KF109'와 'NC82', 시금치 '입추'와 나팔꽃을 생장혼경조절이 가능한 대기오염원 노출상에서 SO? 140ppb/시간 또는 O? 150ppb/시간의 농도로 하루 24시간 10일 동안 노출시킨 결과 '수원25호' 들깨와 담배 'L8'은 SO?에 민감한 반면, 담배 'L8'과 나팔꽃은 오존에 아주 민감한 것으로 판명되었다. 위의 농도에서 가시적 피해가 조사식물의 50%에서 발생하는 병반발생빈도 50%(SF?)를 기준으로 설정한 한계노출시간 조사에서 오존에 대한 한계 노출시간은 담배 'L8'의 경우 24시간, 나팔꽃의 경우 72시간, 담배 'NC82'와 'KF109'의 경우 144시간 내외, 시금치의 경우 216시간으로 추정되었으며, SO?에 대한 한계노출시간은 담배 'L8'의 240시간을 제외하고는 모든 식물에서 240시간 이상으로 추정되었다.

• Journal of Soil and Groundwater Environment
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• v.6 no.1
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• pp.3-12
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• 2001

During ozonation process, the hydroxyl radical generation rates were measured under different experimental conditions (ozone feed rate, nitrobenzene concentration, hydroxyl radical scavenger, pH, HO$_2$O$_2$/O$_3$ etc.) Nitrobenzene could be decomposed by hydroxyl radical rather than ozone only and nitrobenzene decomposition rate was expressed with functions of ozone and nitrobenzene concentration. The rate was decreased as the hydroxyl radical scavenger concentration was increased, and all results were followed pseudo first-order reaction. Using a competitive method, hydroxyl radical generation rate was measured with probe compound and scavenger. It was proportional to ozone concentration, and 0.24mo1 of hydroxyl radical was produced with 1mol of ozone. Under different pH conditions, hydroxyl radical generation rates were measured (pH 10.2 (0.91Ms$^{-1}$ ) > pH 7.3 (0.72Ms$^{-1}$ ) > pH 5.6 (0.67Ms$^{-1}$ ) > pH 3.4 (0.63Ms$^{-1}$ )) showing higher generation rate at high pH values. Addition of hydrogen peroxide promoted the generation rate of hydroxyl radical. Considering the results of pH experiments and addition of hydrogen peroxide experiments, the hydroxyl radical generation rate was 1.6 times higher in hydrogen peroxide solution than in high pH solution, indicating addition of hydrogen peroxide is better promoter to produce the hydroxyl radical in ozonation. These results could be applied to AOPs to remediate the contaminated wastewater and groundwater.

• Journal of Korean Society of Environmental Engineers
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• v.30 no.7
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• pp.743-750
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• 2008

In water treatment plant the Dissolved Ozone Flotation(DOF) System may be employed because this system has various abilities, such that it can remove SS using microbubbles, and it can exert strong oxidation power in removing taste and odor, color, and microbial agents. In order to investigate effectiveness of the DOF system in water treatment, removal characteristics of various water quality parameters were observed depending on the different levels of ozone concentrations. Removal efficiencies of water quality parameters in DOF system were compared with those in DAF(Dissolved Air Flotation) system and in CGS(Conventional Gravity Settling) system. Optimum ozone dose obtained in the pilot experiments was 2.7 mg/L. With increasing ozone dose higher than 2.7 mg/L, removal rates of turbidity, KMnO$_4$ consumption, UV$_{254}$ absorbance, and TOC were reversely lowered. High concentration of ozone dissociate organic matter in water, so that increasing dissolved organic level in effluent. Removal rates of water quality parameters at optimum ozone dose were obtained, such that removal rates of turbidity, KMnO$_4$ consumption, TOC, and UV$_{254}$ asorbance were 88.9%, 62.9%, 47%, and 77.3% respectively. Removal rate of THMFP was 51.6%. For all the parameters listed above, the DOF system was more effective than the DAF system or the CGS system. It is found that the DOF system may be used in advanced water treatment not only because the DOF system is more efficient in removing water quality parameters than the existing systems, but because the DOF system is also required smaller area than the CGS system for the treatment plant.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2003.11a
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• pp.419-420
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• 2003

대기질의 특성 및 변동에 관련된 많은 연구는 대부분이 대도시 또는 대도시 인접지역을 중심으로 이루어져 왔으며, 이러한 연구로부터 대도시에서의 대기질, 특히 오존의 변동 특성 및 기타 오염물질과의 관계 등에 대한 많은 자료가 축적되어왔다. 그렇지만 대도시의 오존농도가 대도시내에서의 생성 및 소멸에만 국한되어 있는 것이 아니라 대기운동과 관련된 수송과도 밀접한 관련이 있다고 밝혀짐에 따라 청정한 대기상태에서 배경농도 특성에 대한 연구의 필요성이 증가하고 있다. (중략)

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.20 no.7
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• pp.58-64
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• 2006

Recently deep interests have been paid on the effective generation of ozone, which has been widely used for water treatment, deodorization, color removal, and chemical processing of exhausted smoke. The silent discharge reaction has been proposed as the most effective one in the many ozone generation methods, because the silent discharge can be generated under the conditions of lower applied voltage and power consumption, compared other ones. In this paper, in order to improve the ozone generation and ozone generation efficiency, the conventional silent discharge chamber with $Al_2O_3$ dielectric layer and tubular ferroelectric bed discharge reactor packed with $Al_2O_3$ pellets were made, and the silent discharge of the reactors were studied experimentally. The ozone generation characteristics are also discussed based on the discharge characteristics, especially on the wall charge accumulation properties and power consumption. The results show that the electric charges of discharge tube with bead are around 2.5 times as large as those without bead. In the discharge chamber packed with dielectric beads, the ozone concentration and the energy yield characteristics were also improved, compared with those in the conventional silent discharge reactor.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2003.11a
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• pp.227-228
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• 2003

대기 오염에 관한 연구가 진행되면서 광화학반응에 기여도가 높고, 인체에 직, 간접적으로 영향을 미치는 Volatile organic carbons(이하 VOCs)를 측정하는데 많은 연구가 진행되어져 오고 있다. Gas chromatography와 같은 sampling method에 의한 농도 측정 방법은 정확한 농도를 측정 할 수 있다는 장점은 있지만, 대기 중 광화학반응 기작을 연구하는데 있어서 오존과 VOCs를 포함한 화학종들의 공간적, 시간적인 농도 변화를 분석하는데 한계를 가지고 있다. (중략)

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2001.11a
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• pp.350-351
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• 2001

대기환경기준물질 중 하나인 오존은 자외선과 코로나 방전에 의해 대기중에서 생성되며(Heisig et al., 1997), 강력한 산화력을 지니고 있기 때문에 많은 유기화합물, 무기화합물을 산화시킨다. 특히 유기화합물의 올레핀류 뿐만 아니라 방향족핵도 실온에서 빠르게 분해시키는 특징이 있다. 이 산화분해력을 이용하여 오존은 탈색, 탈취 표백 또는 유기화합물의 구조를 결정, 화학제품의 합성 등에 이용되고 있다. (중략)