• Progress in Medical Physics
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• v.9 no.1
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• pp.55-64
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• 1998

In recent, the demand of development of the high dose rate brachytherapy source increased for substitute for Co-60 source by iridium source, since the supplying Co-60 source is very depressed and the high dose rate brachytherapy sources are entirely imported from the abroad. This study investigated the exposure rates and isotropic dose distributions for the Ir-192 source produced from $\^$191/Ir(n,r)$\^$192/Ir by nuclear reactor in Korea Atomic Energy Research Institute. The activity of source was obtained an 1.012 Ci (the initial activity without encapsulation was 2,87Ci) by measurement with encapsuled stainless steel. The exposure rate of provided Ir-192 source was determined on 6.36 ${\pm}$ 0.147 Rm$^2$/h-GBq (2.350 ${\pm}$ 0.054 Rcm$^2$/mCi-hr) within ${\pm}$ 2.2% discrepancy with IC-10 ion chamber (0.14 cc) which was mounted on the acrylic jig to 5, 10 and 20 cm from the center of source. The calculated doses with 22 most significant spectrum lines were corrected with intrinsic efficiency of the germanium detector were compared to measured exposure dose rates within ${\pm}$3.8 % discrepancy. The authors confirmed the high dose rate Ir-192 source could be replaced the long decayed Co-60 source via investigation of the isotropic dose distributions in lateral, source axis and diagonal direction of source center are very closed to within 3% uncertainties. Especially, this exposure rate constant and isotropic dose distribution will be fundamental to build the high dose rate source and develop the computed therapy planning system.

• ALGAE
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• v.36 no.4
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• pp.285-298
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• 2021

The amount of CO₂ absorbed by the oceans continues to rise, resulting in further acidification, altering some functional traits of phytoplankton. To understand the effect of elevated partial pressures of CO₂ (pCO₂) on functional traits of dinoflagellates Alexandrium affine and A. pacificum, the cardinal temperatures and chain formation extent were examined under two pCO₂ (400 and 1,000 µatm) over the range of temperature expected to be associated with growth. The growth rate and chain formation extent of A. affine increased with higher pCO₂, showing significant changes in cardinal temperatures and a substantial increase in middle chain-length (4-8 cells) fractionation under elevated pCO₂ condition. By contrast, there were no significant differences in specific growth rate and any chain-length fractionation of A. pacificum between ambient and elevated pCO₂ conditions. The observed interspecies variation in the functional traits may reflect differences in ability of species to respond to environmental change with plasticity. Moreover, it allows us to understand the shifting biogeography of marine phytoplankton and predict their phenology in the Korea Strait.

• Journal of Ocean Engineering and Technology
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• v.36 no.3
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• pp.168-180
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• 2022

The IMO has decided to proceed with the early introduction of EEDI Phase 3, a CO₂ emission regulation to prevent global warming. Measures to reduce CO₂ emissions for ships that can be applied immediately are required to achieve CO₂ reduction. We set six different CO₂ emission scenarios according to the type of ship and fuel, and designed a monoethanolamine-based CO₂ capture process for ships using a rate-based model of Aspen Plus v10. The simulation model using Aspen Plus was validated using pilot plant operation data. A ship inevitably tilts during operation, and the performance of a tilted column decreases as its height increases. When configuring the conventional CO₂ capture process, we considered that the required column heights were so high that performance degradation was unavoidable when the process was implemented on a ship. We applied a parallel column concept to lower the column height and to enable easy installation and operation on a ship. Simulations of the parallel column confirmed that the required column height was lowered to less than 3 TEU (7.8 m).

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.14 no.5
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• pp.433-440
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• 2002

Simulations were carried out to investigate the characteristics of $CO_2$ emissions for an electric powered air conditioning system. The $CO_2$ emissions were evaluated for various simulation parameters such as a power source distribution rate, power plant efficiency, power supply efficiency and system performance (COP). It was found that the $CO_2$ emissions were remarkably decreased by increasing the COP of the electric powered air conditioning system with storage tank. The $CO_2$emission per unit refrigeration capacity is 0.6 kg/RTh. And also, as the COP increase by 0.1, the $CO_2$ emissions decrease by 7.2%.

• Korean Journal of Agricultural and Forest Meteorology
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• v.15 no.4
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• pp.245-263
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• 2013

This study was conducted to find out the influence of elevated atmospheric $CO_2$ concentrations and air temperature on photosynthesis and fruit quality of 'Fuji'/M.9 apple trees and to investigate these to the effects of climate change during the last four years (2009-2012). The treatments employed were: 'Ambient' (ambient temperature + ambient $CO_2$ concentration); 'High $CO_2$' (ambient temperature + elevated $CO_2$ concentration); 'High Temp'. (elevated temperature + ambient $CO_2$ concentration); and 'High $CO_2$ + High Temp'. (elevated temperature + elevated $CO_2$ concentration). The elevated temperature plots were maintained at $4^{\circ}C$ higher than ambient air temperature, while the elevated $CO_2$ plots were maintained at 700 ${\mu}mol{\cdot}mol^{-1}$. Annual treatment period was applied from end of April to beginning of November for four years. Results showed that elevated $CO_2$ decreased stomatal conductance and leaf SPAD value, but increased photosynthetic rate, intercellular $CO_2$ concentration (Ci), and starch content of mesophyll tissue. In the vegetative growth, elevated temperature increased total number of shoot and total shoot growth per tree, but elevated $CO_2$ decreased average shoot length. In the fruit quality, elevated $CO_2$ increased soluble solid content, fruit red color, and ethylene production. In conclusion, elevated $CO_2$ increased photosynthetic rate of apples during the early growth, but effect of increased photosynthetic rate due to elevated $CO_2$ was decreased during latter growth stage. Elevated temperature, on the other hand, tended to decrease photosynthetic rate of apples during the early growth, but that tended to increase during latter growth stage. Both elevated $CO_2$ and temperature tended to decrease the degree of decreased photosynthetic rate due to each factor.

• Korean Journal of Animal Reproduction
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• v.19 no.2
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• pp.135-140
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• 1995

The study was conducted to investigate on the survival rate of bisected porcine embryos co-cultured in 10% FCS(v/v)＋TCM-199 media containing hormones, oviductal epithelial cells and cumulus cells 0 to 72 hrs after bisection. In vitro survival rate was defined as development rate on in vitro culture or FDA-test. The results are summarized as follows ; 1. The survival rate of bisected porcine embryos cultrued in 10% FCS＋TCM-199 media contaning PMSG, hCG, PMSG＋hCG, hCG＋$\beta$-estradiol 0 to 20 hrs and 20 to 40 hrs were 37.6% and 37.5%, 28.6% and 28.6%, 35.7% and 28.8%, 30.8% and 23.1%, 38.5% and 30.7%, respectively. The survival rate of bisected embryos co-cultured in TCM-199 media containing hormones, oviductal epithelial cells and cumulus cells was significantly higher than that of non co-culture. 2. The survival rate of bisected porcine embryos co-cultured 10% FCS＋TCM-199 media containing oviductal epithelial cells 4 to 5 hrs and 20 to 24 hrs were 42.9% and 38.5%, respectively. 3. The survival rate of bisected porcine embryos co-cultured in 10% FCS＋TCM-199 media containing cumulus cells 4 to 5 hrs and 20 to 24 hrs were 40.0% and 35.7%, respectively.

• Journal of Environmental Health Sciences
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• v.34 no.3
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• pp.240-246
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• 2008

The purpose of this study was to gain basic information on the characteristics of $CO_2$ adsorption in relation to $Na_2CO_3$, $K_2CO_3$, $Li_2CO_3$-impregnated activated carbon in a Fixed Bed Reactor. From the results of this study the following conclusions were made: $Na_2CO_3$, $K_2CO_3$, $Li_2CO_3$-impregnated activated carbon had a longer breakthrough time and more enhanced adsorption capacity than activated carbon alone. When tested with isothermal adsorption and tested for $CO_2$ adsorption the amount of $CO_2$ adsorbed varied with temperature, $CO_2$ inlet concentration, gas flow rate, aspect ratio, etc. Based on the results, when Langmuir, Freundlich and Dubinin-Polanyi adsorption isotherms were used for linear regression of isothermal adsorption data, Langmuir adsorption isotherm was the most suitable. And, the optimum condition for $Na_2CO_3$ and $K_2CO_3$ impregnated activated carbon make-up was 1N and $Li_2CO_3$ was 0.1N. It could be concluded that adsorption capacity was decreased with adsorption temperature and increased gas concentration. When the aspect ratio (L/D) was varied 0.5, 1.0 and 2.0, the significant drop of adsorption amount was observed below 1.0 and breakthrough time was shortened with gas flow rate.

• Journal of the Korea Safety Management & Science
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• v.2 no.4
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• pp.187-195
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• 2000

Electrochemical promotion of the reaction rate was investigated for CO oxidation in a solid electrolyte catalytic reactor where a thin film of Pt was deposited on the yttria stabilized zirconia as an electrode as well as a catalyst. It was shown under open circuit condition that potential was a mixed potential of $O_2$exchange reaction and electrochemical reaction induced by CO. The effect of electrochemical modification on the CO oxidation rate was studied at various overpotentials and $P_{CO}$$P_{O2}$.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2008.04a
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• pp.44-47
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• 2008

This paper evaluated the fire characteristics by using furniture calorimeter. Fire property assessment using the furniture calorimeter showed that the heat release rate is maximum 1,600 kW, maximum CO is 0.261%, maximum CO2 is 2.597%, while for the sofa for one person, the maximum heat release rate is approx. 531.5 kW, max. CO is 0.102%, and max. CO2 is 1.011%.

• Applied Chemistry for Engineering
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• v.20 no.4
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• pp.423-429
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• 2009

The purpose of this study is to investigate the optimal condition for the hydrogen-rich gas production and the CO removal by reforming of gliding arc plasma reforming system using biogas. The parametric screening studies were carried out according to changes of steam feed amount, catalyst bed temperature in water gas reactor and catalyst bed temperature, input air flow rate in preferential oxidation reactor. The standard condition is as follows. The steam/carbon ratio, catalyst bed temperature, total gas flow rate, input electric power and biogas composition rate ($CH_4$ : $CO_2$) were fixed 3, $700^{\circ}C$, 16 L/min, 2.4 kW and 6 : 4, respectively. The results are as follow, HTS optimum operating conditions were S/C ratio of 3 and reactor temperature of $500^{\circ}C$. LTS were S/C ratio of 2.9 and temperature of $300^{\circ}C$. Also, PROX I optimum conditions were input air flow rate of 300 mL/min and reactor temperature of $190^{\circ}C$. PROX II were 200 mL/min and $190^{\circ}C$ respectively. After having passed through each reactor, the results were as follows: 55% of $H_{2}$ yield, 0% of CO selectivity, 99% of $CH_4$ conversion rate, 27% of $CO_2$ conversion rate, respectively.