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경상남도 K시 초·중·고등학교의 실내공기질 농도 실태 비교
류재용 ( Jae-yong Ryu ) 한국환경기술학회 2024 한국환경기술학회지 Vol.25 No.2
Indoor air quality (PM<sub>2.5</sub>, PM<sub>10</sub>, CO<sub>2</sub>, HCHO, TCM) concentrations were measured and compared in the f irst (April-May) and second half (September-October) in the 2022 for 19 elementary schools, 11 middle schools, and 9 high schools in K-city, Gyeongsangnam-do. The average concentrations of ultrafine and fine dust were 11.50±6.54 ug/m<sup>3</sup> and 19.93±11.85 ug/m<sup>3</sup> in the first half, and 8.28±3.79 ug/m<sup>3</sup> and 11.85±4.56 ug/m<sup>3</sup> respectively in the second half. It was found that no school exceeded the 35 ug/m<sup>3</sup> and 70 ug/m<sup>3</sup> standards for ultrafine dust and fine dust in the School Health Act. The overall average concentration of carbon dioxide was 657 ± 90.3 ppm and 583 ± 80.6 ppm in the first half and second half, respectively, and no school exceeded the criteria of 1,000 ppm. In the case of formaldehyde, it was found that not only did it not exceed the school health law criteria of 80 ug/m<sup>3</sup>, but it was far below the criteria. The concentration of ultrafine dust, fine dust, and carbon dioxide was slightly higher in the second half than in the first half. However, the concentration of formaldehyde was much higher in the second half than in the first half. The concentration of fine dust and ultrafine dust was somewhat high in elementary school, and the concentration of carbon dioxide was somewhat high in high school.
연구 논문 : 지상 MAX-DOAS를 이용한 중국 베이징에서의 이산화질소 연직분포 산출 및 지상자료와 비교를 통한 검증연구
류재용 ( Jae Yong Ryu ) 대한원격탐사학회 2014 大韓遠隔探査學會誌 Vol.30 No.6
NO2 vertical profiles were retrieved via ground based MAX-DOAS measurements for the summer period in 2006 in Beijing, one of the megacities in the Northeast Asia. Large portion of NO2 load was observed at the 0-1 km layer. We found that NO2 rapidly decreases up to the altitude of 3 km. In addition, the retrieved NO2 mixing ratios within 0-1 km layer were compared with those observed at the surface by in-situ monitor. The correlation coefficient (R) between NO2mixing ratios within 0-1 km layer and those at the surface was calculated to be 0.7. The major causes of such discrepancy are thought to be both differences in measured areas and rapid decrease in NO2 mixing ratio with height.
Powder-Type 산화칼슘(CaO)을 이용한 육불화황(SF<sub>6</sub>) 분해 부산물의 고정화 연구
류재용 ( Jae Yong Ryu ) 한국폐기물자원순환학회 2022 한국폐기물자원순환학회지 Vol.39 No.6
Climate change represents a worldwide warning on global warming and has elevated awareness on the global climate crisis. As a result, worldwide changes to tackle climate change have been initiated. In compliance with the Paris agreement, Korea has declared Carbon Net Zero and implemented legislative changes. Regarding the greenhouse gas emissions in Korea, the mineral industry plays a large role among other industries. A huge amount of greenhouse gases is emitted during the decarboxylation and calcination processes in the cement production process. Therefore, to address the climate crisis, the cement industry also needs to develop technologies to promote carbon neutrality. This study was conducted to explore ways to control SF<sub>6</sub>, of which GWP is the highest, using cement kiln and thermal plasma, and to recycle the byproduct of pyrolysis into an eco-friendly cement supplementary material by immobilizing it with calcium oxide. The destruction and removal efficiency of SF<sub>6</sub> was 100%, while the immobilization reaction rate calculated from the concentration change of the by-product was 99.4%. As a by-product of the immobilization reaction, cement subsidiary raw materials such as fluorite (CaF<sub>2</sub>) and anhydrite (CaSO<sub>4</sub>) were generated, and it is thought that recycling of these raw materials is possible.
류재용 ( Jae-yong Ryu ) 한국환경기술학회 2023 한국환경기술학회지 Vol.24 No.1
The indoor air quality of internet cafes in four metropolitan cities and provinces was investigated. There were 5 measurement items (PM<sub>10</sub>, PM<sub>2.5</sub>, CO<sub>2</sub>, CO, HCHO) of indoor air quality. The research period was from March to June 2021. The total number of internet cafes was 193. Looking at each region, there were 27 in A region, 36 in B region, 33 in C region, and 97 in D region. By month, the number was 52 in March, 35 in April, 56 in May, and 50 in June. The indoor air quality measurement results show the following: The CO<sub>2</sub> concentration in the internet cafes was found to be at least 20 % higher, at most about 50 % higher than the 400 ppm CO<sub>2</sub> concentration in the general atmosphere. The CO concentration in the internet cafes was actually about 2.5 times higher, and at most about 10 times higher than the CO concentration of 0.4 ppm in the general atmosphere. It was found that the indoor HCHO concentration increased with increasing temperature from March to June, 2021. The concentrations of PM<sub>10</sub>, and PM<sub>2.5</sub>, varied slightly by region and month, but generally increased gradually from March to June, 2021.
플라즈마 이용 반도체 공정의 과불화화합물(NF<sub>3</sub>, CF<sub>4</sub>, SF<sub>6</sub>) 분해 연구
류재용 ( Jae-yong Ryu ) 한국폐기물자원순환학회 2018 한국폐기물자원순환학회지 Vol.35 No.3
PFC (perfluorocompound) gases have an extremely high global warming potential (GWP). A study of the destruction of NF<sub>3</sub>, CF<sub>4</sub> and SF<sub>6</sub> gases emitted from the semiconductor industry was attempted by plasma power at 4.4 kW, 5.5 kW, 6.0 kW, 6.6 kW, 7.6 kW, 8.1 kW and 9.1 kW. As electric power increased, DRE (destruction and removal efficiency) of NF<sub>3</sub>, CF<sub>4</sub> and SF<sub>6</sub> was also increased. It was confirmed through experiment that the DRE of NF3 is 99% at 7.6 kW, 97% for CF<sub>4</sub> at 9.14 kW and 100% for SF<sub>6</sub> at 7.6 kW of plasma power. By-products formed by PFC destruction were mainly F<sub>2</sub>, SO<sub>2</sub>F<sub>2</sub>, NOx and CO gases. In addition, particulate matter was formed, and particle were proven to be AlF<sub>3</sub>.
전자빔 기술을 이용한 반도체 공정의 삼불화질소(NF₃) 분해
류재용(Jae Yong Ryu),최창용(Chang Yong Choi),김종범(Jong Bum Kim),이상준(Sang Jun Lee),김승곤(Seung Gon Kim),곽희성(Hee Sung Kwak),윤영민(Young Min Yun) 大韓環境工學會 2012 대한환경공학회지 Vol.34 No.6
전자빔을 이용하여 반도체 공정에서 배출되는 NF3 가스 분해 연구를 수행하였다. 본 연구에서 흡수선량은 0에서 400kGy 범위였고, 전류강도는 0~20mA범위였다. 또한, 처리 대상 가스의 농도 범위는 500~2,000ppm이었다. 그리고 조사시간의 영향을 알기 위해서, 조사시간을 각각 5초, 10초, 15초, 20초 등으로 달리 하면서 실험을 수행하였다. 흡수선량 및 전류 강도가 증가할수록 가스의 분해효율은 증가하였다. 하지만 처리 대상가스의 농도가 증가할 때는 분해효율이 감소함을 알 수 있었다. 흡수선량이 약 400kGy일 때 처리가스의 분해효율은 약 90% 정도를 나타내었다. The destruction study of NF3 gas emitted from the semiconductor industry is performed with electron-beam technology. Absorbed dose (kGy) and current ranged from 0 (0) to 400kGy (20mA). The concentration of NF3 gas ranged from 500 to 2,000ppm. In order to assess the effect of a residence time on DRE (Destruction and Removal Efficiency, %), experiments also conducted at different irridiation times of 5 sec, 10 sec, 15 sec and 20 sec respectively. As absorbed dose and current increased, DRE of NF3 was also increased. However, DRE (%) of NF3 decreased with increasing the concentration of NF3 gas. The DRE of NF3 was about 90% at an absorbed dose of 400kGy.
수소첨가에 의한 육불화황(SF6) 분해효율 향상 기초연구
류재용 ( Jae Yong Ryu ),김종범 ( Jong Bum Ki ),최창용 ( Chang Yong Choi ),장성호 ( Seong Ho Jang ),이상준 ( Sang Joon Lee ) 한국환경과학회 2012 한국환경과학회지 Vol.21 No.9
Destruction and removal efficiency (DRE) of SF6 was tested with low degrees of ionization. The applied dose of ionization energy varied from 63.70 to 212.34kGy. The initial concentration and flow rate of SF6 gas were 1,000ppm and 50L/min, respectively. In order to increase the DRE, injection of conditioning agent (H2) were conducted. The DRE of SF6 increased about 2 times with injection of H2 gas.