• Proceedings of the Korea Air Pollution Research Association Conference
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• 2003.11a
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• pp.251-254
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• 2003

'UNEP Global Environment Outlook 2000'의 자료에 의하면, 향후 1000년에 가장 심각한 환경문제는 "지구온난화" 였다. $CO_2$ 농도 증가 등으로 인한 기후변화로 지난 100년간 전 세계적으로 기온은 평균 0.3~0.6$^{\circ}C$ 상승, 해수면은 평균 25 cm 내외 상승, 프레온가스 등으로 인하여 성층권의 오존층이 파괴되어 피부암과 안질환이 급증하고 면역기능이 저하되며, 현종 식물종 8%, 조류 11%, 어류 5%, 포유류 14%가 멸종위기에 처하는 등 생물다양성의 감소, 내분비계 장애물질(환경호르몬) 증가로 유해화학물질에 더욱 노출되고 있다. (중략)

• Clean Technology
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• v.27 no.4
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• pp.350-358
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• 2021

The results of this study shows that the combustor temperature ranged from 848.27 to 1,026.80 ℃, averaging about 976.61 ℃, and the NOx concentration increased as the temperature increased. The urea usage ranged from 291.00 to 693.00 kg d^-1, averaging about 542.34 kg d^-1, and the NOx concentration decreased as the urea usage increased. Residence time was about 3.38 to 9.17 s, averaging about 5.22 s, about 2.61 times larger than the 2 s of the design details. This is 1,086 kg h^-1, averaging about 55.71%, compared to the 1,950 kg h^-1 SRF input permission standard. The combustion chamber area is constant, but the residence time is shown to increase with the decrease of exhaust gas. The O₂/CO ratio was 847.05 to 14,877.34, averaging about 3,111.30, and the NOx concentration slightly increased as the O₂/CO ratio increased. As the combustor temperature and O₂/CO ratio increased, the combustion reaction with nitrogen in the air increased and the NOx concentration slightly increased. As the urea usage and residence time increased, the NOx concentration decreased slightly with an increase in reactivity with NOx. The NOx concentration at the stack ranged from 7.88 to 34.02 ppm with an average of 19.92 ppm, and was discharged within the 60 ppm emission limit value. The NOhx emission factor was 1.058 to 1.795 kg ton^-1, averaging about 1.450 kg ton^-1. This value was about 24.87% of the maximum emission factor of 5.830 kg ton^-1 of other solid fuels. Other synthetic resins and industrial wastes were 79.80% and 43.65% compared to 1.817 kg ton^-1 and 3.322 kg ton^-1, respectively. This value was similar to 1.400 kg ton^-1 of RDF in the NIER notice (2005-9), 10.98% compared to the maximum SRF of 13.210 kg ton^-1. Therefore, the NOx emission factor had a large deviation.

• Korean Journal of Agricultural and Forest Meteorology
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• v.9 no.4
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• pp.268-276
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• 2007

Urban atmosphere may play as a harbinger for the future climate change with respect to temperature and $CO_2$ concentration. The Seoul metropolitan area is unique in rapid urbanization and industrialization during the last several decades, providing a natural $CO_2$ dome with increased temperature. This study was carried out to evaluate the feasibility of using the urban-rural environmental gradient in replacement of the IPCC mid-term scenario (after 30-50 years). For this, we measured atmospheric $CO_2$ concentration and air temperature at three sites with different degree of urbanization (Seoul, Suwon, and Icheon). Results from 11-month measurement can be summarized as follows: (1) The annual mean $CO_2$ concentration across 3 sites was in the order of Seoul (439 ppm) > Suwon (419 ppm) > Icheon (416 ppm), showing a substantial urban-rural environmental gradient. (2) The diurnal fluctuation in $CO_2$ concentration was greater in summer than in winter, showing the effect of photosynthesis on local $CO_2$ concentration. (3) The daily maximum $CO_2$ concentration was observed at 0500 LST in spring and summer, 0800 LST in autumn, and 0900 LST in winter, showing the sunrise-time dependence. (4) The observed hourly maximum $CO_2$ concentration averaged for the whole period was 446 ppm in Seoul at 0700 LST, while the minimum was 407 ppm in Suwon at 1500 LST. (5) Compared with the background atmospheric concentration of $CO_2$ in Anmyeon-do (377.4 ppm annual mean), $CO_2$ concentration of the study sites was higher by 14% in Seoul, by 10% in Suwon, and by 9% in Icheon. The observed $CO_2$ concentration in Seoul reached already 98% of the 2030-2040 projection (450 ppm) and 80% of the 2040-2050 projection (550 ppm) under the IPCC BAU scenario, showing a feasibility of using the $CO_2$ dome of Seoul as a natural experimental setting for the mid-term climate change impact assessment.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1995.04a
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• pp.85-85
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• 1995

전년도에 ara-C 유도체 중에서 ara-CDP-DL-PTBA가 각종 암세포주에 대한 뛰어난 항암작용이 보고된바 있으며, 이후 시료의 대량확보, Bulk Formulation 및 전임상등의 세가지 분야에 관해 연구를 수행하였다. Ara-CDP-DL-PTBA를 수용액에 현탁, 초음파분쇄후 NICOMP Analysis에 의하여 micellar solution의 입자도를 알아 본 결과 fresh prepared micelles은 11,1mm size가 88.63%이며 50,5mm가 11.37%로 나타나 평균 19,0mm가 되고, Reconstructed micells은 10.9mm size가 99.87%이며 356.1mm가 0.13%로 나타나 평균 11.0mm가 된다. Ara-C와 Ara-CDP-DL-PTBA의 대사작용을 알아본 결과, ara-C는 투여 1시간째 2,850 $\pm$ 450 pmol, 4시간째 450$\pm$190 pmol, 24시간째 30 pmol 이하로 ara-CTP의 혈중 농도가 급격히 감소하는 반면에 ara-CDP-DL-PTBA는 1시간째 650$\pm$120 pmol, 2시간째 1,800$\pm$500 pmol, 24시간째 300$\pm$90 pmol으로 ara-CTP의 혈중 농도가 서서히 감소하였다.

• Journal of Preventive Medicine and Public Health
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• v.24 no.4 s.36
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• pp.507-515
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• 1991

One, two, six and ten week old Sprague-Dawley rats were exposed to carbon monoxide at 3,700 ppm for 30 minutes, and carboxyhemoglobin was measured immediateley. 5, 30, 60, 90, 120 minutes after the exposure. In each time after the exposure, the means of the carboxyhemoglobin levels were compared among the week age groups. The regression analysis was done using the natural logarithm of the carboxyhemoglobin concentration as a dependent variable and the time after the exposure as an independent vaiable. From the regression equation, the half lives of the carboxyhemoglobin were calculated. The one week old rats showed significantly higher carboxyhemoglobin level than other week age rats in the entire time after the exposure. The corrected carboxyhemoglobin concentration calculated by subtracting the normal carboxyhemoglobin level from the measured carboxyhemoglobin at each age group, showed no uniform differences.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.35 no.6
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• pp.543-547
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• 1990

Diurnal courses of $CO_2$ concentration and air temperature in the rice seedbed tunnel covered with polyethylene film, subjected to three different ventilation methods, were traced. Regaredless of ventilation methods, $CO_2$ concentrations in the tunnel on a clear day were lower than that in ambient air, and vice versa before dawn. $CO_2$ concentration during the day was lowest in the tunnel with non-ventilation (NV), followed by horizontal slit ventilation (HSV) and traditional one(TN), reaching down to the lowest level of 58ppm, 155ppm and 272ppm, respectively. Air temperature in the tunnel reached 46$^{\circ}C$ in NV, 37$^{\circ}C$ in HSV and 32$^{\circ}C$ in TV at the daytime when ambient air temperature was 22$^{\circ}C$. Even at night time of ambient air temperature below 15$^{\circ}C$, HSV was more effective than TV in raising the air temperature in the tunnel. The dry weight of 40-day old seedling weighed heaviest in HSV, followed by TV and NV.

• Korean Journal of Remote Sensing
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• v.31 no.6
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• pp.549-560
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• 2015

With the global scale impact of atmospheric $CO_2$ in global warming and climate system, it is necessary to monitor the $CO_2$ concentration continuously on a global scale, where satellite remote sensing has played a significant role recently. In this study, global monthly $CO_2$ concentrations obtained by satellite remote sensing were compared with ground-based measurements at Anmyeon-do and Gosan Korean Global Atmosphere Watch Center. Atmospheric $CO_2$ concentration has increased from 371.87 ppm in January 1999 to 405.50 ppm in December 2013 at Anmyeon-do station (KMA, 2013). Comparison of the continuous measurements by flask air sampling at Anmyeon-do shows the same trend and seasonal variations with those of global monthly mean dataset. Nevertheless, the trends of $CO_2$ over Northeast Asia showed the higher than those of global and the trends also changes with different slope. $CO_2$ products derived from Greenhouse Gases Observing Satellite (GOSAT) and Atmospheric Infrared Sounder (AIRS) were compared with ground-based measurement at Anmyeon-do. The monthly mean values of GOSAT and AIRS data are systemically lower than those obtained at Anmyeon-do, however, the seasonal cycle of satellite products present the similar trend with values of global and Anmyeon-do. The accuracy of $CO_2$ products from GOSAT and AIRS were evaluated statistically for two years from January 2011 to December 2012. GOSAT showed good correlation with the correlation coefficient, RMSD and bias of 0.947, 5.610 and -5.280 to ground-based measurements respectively, while AIRS showed reasonable comparison with 0.737, 8.574 and -7.316 at Anmyeon-do station, respectively.

• Journal of the Korean GEO-environmental Society
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• v.9 no.6
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• pp.13-19
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• 2008

The objectives of this paper are to investigate states of these open dumping landfills for managing, utilizing and stabilization of a municipal solid waste landfill site in environmentally secure conditions. The result of the physical analysis of the landfill showed that it is composed of between 29.72-63.84% organic matter, 32.88% vinyl plastic. The environmental assessment of the landfill site confirmed that the landfill is at a maturation phase due to 0.18 of $BOD_5$/CODcr of leachate. VS and FS of TS Was respectively 30.37%, 32.34% and C/N ratio was 21.8. Surface water around landfill was BOD 10.7 mg/g, SS 37.8 mg/g, E-Coli 31,157(MPN/$100m{\ell}$) and Ground water was $COD_{Mn}$ 1.13-1.38 mg/g, $NO_3-N$ 1.025-4.075 mg/g. Leachat indicated T-P 0.002-0.028 mg/g, $NH_3-N$ 4.0-21.0 mg/g. The soil contamination of around landfill didn't appear as below of the regulation of Soil Environment Conservation Act. The Landfill Gas was $CH_4$ 13.25%, $CO_2$ 6.17%, H2S and CO was not detected. Also Surface Water was not detected $CO_2$, $CH_4$, $H_2S$, CO.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.4
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• pp.1440-1446
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• 2012

This paper presents an experimental study of heat transfer and pressure drop characteristics of supercritical carbon dioxide with PAG inside a horizontal microfin tube. Heat transfer coefficient and pressure drop gradients were measured at 10 MPa in pressure and 520 kg/$m^2s$ in mass flux with variation of PAG mass concentration from 0.06% to 2.26%. The tendencies of both heat transfer and frictional pressure drop characteristics show the same as those of pure $CO_2$ up to 0.3% in PAG mass concentration. In case of 2.26% in PAG mass concentration, measured heat transfer coefficients showed 50% lower than those of pure $CO_2$ near the pseudocritical temperature and measured frictional pressure drop gradients show 1.6 times higher in comparison with those of pure $CO_2$ at $60^{\circ}C$ in $CO_2$ bulk temperature.

• Clean Technology
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• v.16 no.2
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• pp.124-131
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• 2010

Effects of $Ca(OH)_2$ concentration (0.16~0.64 wt%), surfactant concentration (2~16 wt%), total volumetric flow rate (3~6 L/min) and $CO_2$ volume fraction $(0.3{\sim}0.6)$ on morphology, crystal structure, mean particle diameter, aggregation and specific surface area of the precipitated $CaCO_3$ were investigated in the slurry bubble column reactor. Experiments were carried out in acrylic reactor ($0.11\;m-ID{\times}1.0\;m-high$) with a internal tube ($0.04\;m-ID{\times}1.0\;m-high$h). The reaction time of $CaCO_3$ synthesis decreased with adding Dispex N40 of the anionic surfactant. The reaction rate of $Ca(OH)_2$ increased with increasing the volumetric flow rate of $CO_2$. From SEM images, the single crystal of $CaCO_3$ increased with increasing the reaction rate in the saturated concentration of $Ca(OH)_2$ (0.16 wt %) and the concentration of Dispex N40 (2 wt%). The mean particle size of $CaCO_3$ varied with adding Dispex N40. In addition, the specific surface area of $CaCO_3$ increased with adding of surfactant (2 wt%) from $35m^2/g$ to $44m^2/g$ at the volumetric flow rate of $CO_2$ (0.9 L/min) and the concentration of $Ca(OH)_2$(0.64 wt %).