• 한국입자에어로졸학회지
• /
• 제9권2호
• /
• pp.89-102
• /
• 2013

24-hr $PM_{2.5}$ samples were collected from January 19 through February 27, 2009 at an urban site of Gwangju and analyzed to determine the concentrations of organic and elemental carbon(OC and EC), water-soluble OC(WSOC), eight ionic species($Na^+$, $NH^{4+}$, $K^+$, $Ca^{2+}$, $Mg^{2+}$, $Cl^-$, ${NO_3}^-$ and ${SO_4}^{2-}$), and 22 elemental species. Haze phenomena was observed during approximately 29%(10 times) of the whole sampling period(35 days), resulting in highly elevated concentrations of $PM_{2.5}$ and its chemical components. An Asian dust event was also observed, during which $PM_{2.5}$ concentration was 64.5 ${\mu}g/m^2$. Crustal materials during Asian dust event contributed 26.6% to the $PM_{2.5}$, while lowest contribution(5.1%) was from the haze events. OC/EC and WSOC/OC ratios were found to be higher during haze days than during other sampling days, reflecting an enhanced secondary organic aerosol production under the haze conditions. For an Asian dust event, enhanced concentrations of OC and secondary inorganic components were also found, suggesting the further atmospheric processing of precursor gases during transport of air mass to the sampling site. Correlations among WSOC, EC, ${NO_3}^-$, ${SO_4}^{2-}$, and primary and secondary OC fractions, which were predicted from EC tracer method, suggests that the observed WSOC could be formed from similar formation processes as those of secondary organic aerosol, ${NO_3}^-$ and ${SO_4}^{2-}$. Results from principal component analysis indicate also that the observed WSOC was strongly associated with formation routes of the secondary organic and inorganic aerosols.

• 한국지하수토양환경학회지:지하수토양환경
• /
• 제22권6호
• /
• pp.22-28
• /
• 2017

The accuracy of analytical results in response to the use of different additives ($NH_4Cl$, KCl, $LaCl_3$) and oxidant gases was evaluated and compared by using Atomic Absorption Spectrometry (AAS). Identification of spectroscopic interferences and possible improvements in Inductively Coupled Plasma-Atomic Emission Spectrometry (ICP-AES) analysis were also discussed. The average accuracies of total chromium using Certified Reference Materials (CRMs) were found to be 72.1~94.2% in air/acetylene flame condition by AAS, and they were improved to 100.5~110.5% when the oxidants was changed to nitrous oxide rather than adding the additives. The field samples showed similar trends to CRMs, but chromium concentrations were highly variable depending on analytical conditions. The average accuracies using CRMs were estimated to be 89.3~166.1% by ICP-AES, and improved to below 121.7% after eliminating iron interference. Field samples with low chromium and high iron concentration were measured to be > 30% lower in total chromium concentrations by ICP-AES than AAS in nitrous oxide/acetylene flame. Total chromium concentrations in soil could be analyzed with better accuracy under nitrous oxide/acetylene flame by AAS because it was more effective to increase the temperature of the flame than to eliminate the chemical interference for maximizing atomization of chromium. When using ICP-AES, interference substances, total chromium levels, and analytical conditions should be also considered.

• Journal of Microbiology and Biotechnology
• /
• 제10권3호
• /
• pp.338-343
• /
• 2000

The growth capabilities of three $highly-CO_2-tolerant$ microalgae under high concentrations of $CO_2$ were compared for their tolerance to $SO_2$ and NO, the major inhibitory compounds present in flue gases. Although all strains showed good growth with 15% $CO_2$, Chlorella KR-1 exhibited the most desirable properties for $CO_2$ fixation among the strains compared. While Chlorella sp. HA-1 exhibited the best tolerance to NO among the other strains tested, Chlorella sp. KR-1 showed higher tolerance to $SO_2$ than the other two strains tested.

• 한국연소학회:학술대회논문집
• /
• 한국연소학회 2004년도 제29회 KOSCI SYMPOSIUM 논문집
• /
• pp.91-96
• /
• 2004

Simultaneous CH and OH planar laser induced fluorescence(PLIF) and stereoscopic particle image velocimetry (PIV) measurements have been developed to investigate the local flame structure of turbulent premixed flames. The developed simultaneous two radical concentrations and three component velocity measurements on a two-dimensional plane was applied for relatively high Reynolds number turbulent premixed flames in a swirl stabilized combustor. All measurements were conducted for methane-air premixed flames in the corrugated flamelets regime. Strong three-dimensional fluctuation implies that misunderstanding of the flame/turbulent interactions would be caused by the analysis of two-component velocity distribution in a cross section. Furthermore, comparisons of CH-OH PLIF and three-component velocity field show that the burned gases not always have high-speed velocity in relatively high Reynolds number turbulent premixed flame. The Reynolds number dependence of the flame front was clearly captured by the simultaneous CH-OH PLIF and stereoscopic PIV measurements.

• International Journal of Advanced Culture Technology
• /
• 제6권2호
• /
• pp.129-136
• /
• 2018

Our present study, we impregnated Al-Fe-Mg-Si (NFM) nanocomposites having various concentrations 0, 1000, 3000, and 5000 mg/L in biomass in order to make carbonized biomass. We characterized the properties of the impregnated samples through thermogravimetric/differential thermal analysis (TG-DTA), pore distribution, scanning electron microscopy (SEM). The best results were observed for a NFM nanocomposites concentration of 5000 mg/L. After the first heat treatment, carbonization, and activation processes, the fixed carbon ratio and iodine adsorptivity were increased by 21.89% and 368 mg/g, 23.98% and 475 mg/g, 26.40% and 238 mg/g, respectively. The remove rate of malodorous and VOCs were that the sample shows good removal capabilities. From above results, our sample could be used for the removal of noxious and malodorous gases and for the purification of wastewater.

• 한국환경과학회지
• /
• 제6권6호
• /
• pp.637-644
• /
• 1997

The purpose of thins study was to quantitatively determine the Indoor Infiltration of pollutants of outdoor origin. The relationship between Indoor and outdoor air is dependent, to a large extent. on the rate of k exchange between these two environments. Mean Indoor/outdoor ratios measured from thins study were: 0.70 for HNO3; 1.60 for HNO2: 0.56 far SOg: 1.30 for mf3: 0.96 for PM2.5(dP<2.5mm: 0.89 for SO4a': 0.87 for NO3· and 0.79 for NH4 'Mean Indoor concentrations for PMa s, SO4a., HNO9, NO3 and NIL' were similar to outdoor levels. Indoor HNO2 and mB3 values were h19her than outdoors. However, the Indoor level of SO2 was lower than ambient level.

• 대한화학회지
• /
• 제43권2호
• /
• pp.156-160
• /
• 1999

메탄-산소를 아르곤으로 희석한 혼합기체의 점화 과정을 1516-1937K 온도 범위에서 반사 충격파를 이용하여 고찰하였다. 메탄 기체의 점화 지연 시간은 충격관 끝에서 5.0 cm 떨어진 곳에서의 압력 변화 및 광 방출을 측정하여 구하였으며, 각 혼합기체의 농도 의존도 및 온도 의존도에 관한 실험식을 구할 수 있었다. 메탄 산화 과정에 관한 실험 결과를 설명하기 위해 GRI 1.2 메카니즘을 이용한 컴퓨터 모의 실험을 수행하였다.

• 센서학회지
• /
• 제16권2호
• /
• pp.91-96
• /
• 2007

The characteristic of tellurium thin films was studied for detecting nitrogen dioxide gas at room temperature. The film was deposited on $Al_{2}O_{3}$ substrate by using thermal evaporator. The subsequent process was heat treatment by several conditions. (temperature, flowed gases) Surface and grain boundary was investigated using SEM. The results showed that resistance of the tellurium film decreases reversibly in the presence of nitrogen dioxide. The sensitivity of this device depends on the gas concentration and detect lower concentrations less than 10 ppm.

• Journal of Biosystems Engineering
• /
• 제24권5호
• /
• pp.415-424
• /
• 1999

This study was conducted to assess performances of the developed environmental control systems under various seasons of Korea. In all trials for the environmental control systems, the manure pit ventilation system in the windowless pig-housing with partly slatted floor was used. Consequently, under all seasons of Korea, the complex environmental control systems could comfortably maintain the indoor temperature (14.8~27.2$^{\circ}C$) , concentrations of noxious gases (CO2 gas : 631~1,874ppm, NH3 gas : 0.3~3.2ppm), air velocity (0.11~0.23m/s), air movement, and so on. Therefore, the performances of the complex environmental control systems were evaluated as proper as the intended.

• 한국연소학회:학술대회논문집
• /
• 한국연소학회 2004년도 제28회 KOSCO SYMPOSIUM 논문집
• /
• pp.118-123
• /
• 2004

The combustion characteristics of 0.03MW turbulent methane/oxygen diffusion flames have been investigated to give basic informations for designing industrial oxyfuel combustors. NOx reduction has become one of the most determining factors in the combustor design since 3-5% nitrogen is intrinsically included from the current oxygen producing processes. Flame lengths and NOx concentrations were measured by varying flow velocities with and without installing quarls. Flame stabilities are significantly enhanced by oxyfuel combustion in contrast to air-fuel combustion. Flame length decreases with increasing fuel or oxygen velocity because of the enhancement of turbulent mixing. NOx concentration was reduced with increasing flo velocities. This can be attributed to the entrainment of inert product gases into flame decreasing flame temperature. The installation of quarl on the burners rather increased NOx concentration since the quarl blocked the entrainment above the nozzles.