• The Journal of the Convergence on Culture Technology
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• v.10 no.3
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• pp.819-825
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• 2024

The reason for recording dose data when using a diagnostic radiation source is to record and manage the dose to healthcare personnel and patients. The purpose of this study was to verify the difference in radiation dose when using diagnostic radiation generating devices and to inform users' awareness of dose reduction through measurement and analysis of dose in situations with and without shielding. The dose analysis of each equipment for two Korean C-arms and two German C-arms showed that the Korean FPD type C-arm had the highest dose value, followed by the German I.I type C-arm, German FPD type C-arm, Korean, and I.I type C-arm. The results of the dose analysis with and without shielding showed that the dose to the human phantom in a normal atmosphere increased by about 2 times due to scattered radiation, but the dose to the human phantom was reduced by about 5 times by wearing a shield (0.5mm/lead apron). More important than the management of radiation dose is the study of how to reduce exposure when using radiation, and since the radiation dose output from different equipment is different, it is necessary to provide dose information with and without shielding.

• Korean Journal of Soil Science and Fertilizer
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• v.41 no.6
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• pp.399-407
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• 2008

Importance of climate change and its impact on agriculture and environment has increased with a rise of greenhouse gases (GHGs) concentration in Earth's atmosphere, which had caused an increase of temperature in Earth. Greenhouse gas emissions such as methane($CH_4$) and nitrous oxide($N_2O$) in the field need to be assessed. GHGs fluxes using chamber systems in the fields(2004~2005) with pepper cultivation were monitored at the experimental plots of National Academy of Agricultural Science(NAAS), Rural Development Administration(RDA) located in Suwon city. $N_2O$ emission during pepper growing period was reduced to 74.0~82.1% in sandy loam soil compared with those in clay loam soil. Evaluating $N_2O$ emission at different levels of soil water conditions, $N_2O$ emission at -50 kPa were lowered to 13.2% in clay loam soil and 40.2% in sandy loam soil compared with those at -30 kPa. $CH_4$ emission was reduced to 45.7~61.6% in sandy loam soil compared with those in clay loam soil. Evaluating $CH_4$ at different levels of soil water conditions, $CH_4$ emission at -50 kPa was lowered to 69.6% in clay loam soil and 55.8% in sandy loam soil compared with those at -30 kPa. It implied that -50 kPa of soil water potential was effective for saving water and reducing GHG emissions. From the path analysis as to contribution factors for $N_2O$ emission, it appeared that contribution rate was in the order of mineral N(51.2%), soil temperature (25.8%), and soil moisture content(23.0%) in clay loam soil and soil moisture content(39.3%), soil temperature (36.4%), and mineral N(24.3%) in sandy loam soil.

• Clean Technology
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• v.24 no.3
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• pp.212-220
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• 2018

Oxy-fuel combustion is considered as a promising greenhouse gas reduction technology in power plant. In this study, the behaviors of NO and $SO_2$ were investigated under the condition that in-furnace $deNO_x$ and $deSO_x$ methods are applied in oxy-fuel circulating fluidized bed combustion condition. In addition, the generation trends of $SO_3$, $NH_3$ and $N_2O$ were observed. For the purpose, limestone and urea solution were directly injected into the circulating fluidized bed combustor. The in-furnace $deSO_x$ method using limestone could reduce the $SO_2$ concentration in exhaust gas from ~403 to ~41 ppm. At the same experimental condition, the $SO_3$ concentration in exhaust gas was also reduced from ~3.9 to ~1.4 ppm. This trend is mainly due to the reduction of $SO_2$. The $SO_2$ is the main source of the formation of $SO_3$. The negative effect of $CaCO_3$ in limestone, however, was also appeared that it promotes the NO generation. The NO concentration in exhaust gas reduced to ~26 - 34 ppm by appling selective non-catalytic reduction method using urea solution. The $NH_3$ concentration in exhaust gas was appeared up to ~1.8 ppm during injection of urea solution. At the same time, the $N_2O$ generation also increased with increase of urea solution injection. It seems that the HNCO generated from pyrolysis of urea converted into $N_2O$ in combustion atmosphere. From the results in this study, the generation of other pollutants should be checked as the in-furnace $deNO_x$ and $deSO_x$ methods are applied.

• Korean Journal of Soil Science and Fertilizer
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• v.35 no.4
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• pp.216-222
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• 2002

Field experiments were conducted to investigate the effect of various cultural practices on methane($CH_4$) emission in tillage and no-tillage practice in a clayey paddy soil from 1998 to 2000. The factors evaluated in tillage and no-tillage methods were types of nitrogen fertilizers, application method of chemical fertilizers, rice straw application and cultivation method. Of the nitrogen fertilizers, the amount of $CH_4$ emission in ammonium sulfate plot was the lowest, regardless of tillage and the application method. 26.4~41.1% of reduction by ammonium sulfate compared with urea. But in no-tillage which have problem of poor rice yield than tillage, coated urea was more effective nitrogen fertilizer because that showed similar $CH_4$ emission and highest rice yield at 80% of dosage of nitrogen. No-tillage plot emitted lower $CH_4$ than tillage plot where the fertilizers were incorporated. On the contrary, no-tillage plot showed a little higher $CH_4$ emission compared with tillage plot for the surface application. When rice straw was applied, no-tillage practice reduced methane emission by 26.6% compared with tillage practice, but showing a little difference of 10.7% in no application. With cultivation method, no-tillage practice reduced methane emission 26.6% compared with tillage for the 30-d-old seedling transplanting. But for the dry direct seeding practice, no-tillage was a less effective because considerable amounts of rice straw incorporated by tillage were more decomposed aerobically in the soil and emitted as $CO_2$ to the atmosphere with flooding in no-tillage soil.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.6
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• pp.1239-1244
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• 2011

Importance of climate change and its impact on agriculture and environment has increased with a rise of greenhouse gases (GHGs) concentration in Earth's atmosphere. Nitrous oxide ($N_2O$) emission in upland fields were assessed in terms of emissions and their control at the experimental plots of National Academy of Agricultural Science (NAAS), Rural Development Administration (RDA) located in Suwon city. It was evaluated $N_2O$ emissions with different growing periods (spring and autumn seasons), tillage and no tillage conditions in a chinese cabbage field. The results were as follows: 1) An amount of $N_2O$ emissions were high in the order of Swine manure compost>NPK>Hairy vetch+N fertilizer. By tillage and no tillage conditions, $N_2O$ emissions were reduced to 33.7~51.8% (spring season) and 31.4~76.7% (autumn season) in no-tillage than tillage conditions. 2) In autumn season than those spring season, $N_2O$ emissions at NPK, hairy vetch+N fertilizer and swine manure compost were reduced to 49.6%, 39.0% and 60.0%, respectively, in tillage treatment and 59.5%, 70.6% and 58.7%, respectively, in no-tillage treatment. 3) $N_2O$ emission measured in this study was 15.2~86.4% lower with tillage and no tillage treatments than that of the IPCC default value (0.0125 kg $N_2O$-N/kg N).

• Journal of the Korean Ceramic Society
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• v.40 no.5
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• pp.494-500
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• 2003

The effects of $Al_2$O$_3$ addition upon the sintering range of clay-EAF dust (the specified wastes produced from steel making process) system body which would be used as a constructing bricks were investigated. The slope of apparent density to sintering temperature decreased for Clay-dust body containing 5~15 wt% A1203 sintered at 1200-125$0^{\circ}C$, and the absorption(%) of specimen sintered above 125$0^{\circ}C$ decreased due to the formation of open pores produced by pore bloating. For the specimen without any $Al_2$O$_3$ addition sintered at 1275$^{\circ}C$, the major phase was cristobalite, the small amount of mullite (3Al$_2$O$_3$ 2SiO$_2$) formed and the hematite (Fe$_2$O$_3$) remained. In the Clay-dust system body containing $Al_2$O$_3$ 15 wt%, however, the cristobalite disappeared and the major phase was mullite. Also the part of $Al_2$O$_3$ reacted with hematite to form hercynite (FeAl$_2$O$_4$). From the these results, addition of $Al_2$O$_3$ to Clay-dust system body enlarges a sintering range; decreasing an apparent density and absorption slop to sintering temperature owing to consumption of liquid phase SiO$_2$ at higher temperature and gas-forming component Fe$_2$O$_3$ at reduced atmosphere which would decrease an amount of liquid formed and increase the viscosity of the liquid produced during the sintering process.

• Journal of Bio-Environment Control
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• v.20 no.3
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• pp.221-226
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• 2011

The study was carried out to investigate the effect of MA packaging materials on quality and storability of tomato in long distance export condition. We found that the fresh weight loss in perforated film was higher than other breathable films. The fresh weight of tomato (cv 'Madison') packaged with breathable films, such as 5,000 cc, 10,000 cc, $20,000cc/m^2{\cdot}day{\cdot}atm$ oxygen permeable films, reduced less than 0.6%, but perforated film that already being used for packaging horticultural crops showed 1.4% fresh weight loss during $5^{\circ}C$ storage for 20 days and then $20^{\circ}C$ storage for last 5 days with 85% relative humidity. The carbon dioxide and oxygen concentration in tomato packages showed proper level for MA storage in $20,000cc/m^2{\cdot}day{\cdot}atm$ $O_2$ breathable film treatment at $5^{\circ}C$ storage. Although at $20^{\circ}C$ storage, the carbon dioxide concentration increased sharply, the oxygen concentration decreased remarkably, the change of these gases concentration was the lowest in 20,000 cc film treatment. The ethylene concentration was sharply increased at $20^{\circ}C$ from $21^{st}$ day to $25^{th}$ day after $5^{\circ}C$ storage for 20 day, and the concentration was lower in 20,000 cc film treatment among the breathable film treatments. Until 20 days, at $5^{\circ}C$ storage all treatments did not exceed the marketability. However, the last 5 days during at $20^{\circ}C$, the fruit appeared fungal rots and the quality rapidly decreased. The $20,000cc/m^2{\cdot}day{\cdot}atm$ $O_2$ permeability treated tomato performed higher firmness (9.56 N), vitamin C (16.31 mg/100 gFW), and soluble solids ($7^{\circ}Brix$) than other breathable films at final storage day. The results suggest that the $20,000cc/m^2{\cdot}day{\cdot}atm$ $O_2$ permeable film treatment of tomato (cv 'Madison') performed the highest quality and storability of tomato for long distance exporting.

• Korean Journal of Food Science and Technology
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• v.29 no.1
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• pp.57-64
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• 1997

The research was investigated to determine the effect of organic acids or packaging methods (PA) either alone or in combination on the quality of Aster scaber during storages. The Aster scaber was treated with organic acids and PA, and stored at different temperature $(1\;and\;5^{\circ}C)$. Total plate counts, weight loss, color change, and sensory evaluation were evaluated. Both organic acid treatments, PA, and combined treatment had little effect on the inhibition of total plate counts compared to the control (non-treatment). Organic acid treatments showed less weight reduction compared to the control and nitrogen treated package had the least weight reduction, but the combined treatments showed less weight reduction than organic acid treatments or packaging method alone. Organic acid treatments were little different from the control on color change, but nitrogen packages had the least color change, whereas combined treatments were a little reduced, but little different compared to the control or nitrogen packages. The nitrogen packages showed better effects on the sensory evaluation compared to other treatments and the results of sensory evaluation were consistent with that of weight reduction and color change, but not in total counts. All these results showed better effects in $5^{\circ}C$ rather than $1^{\circ}C$.

• Atmosphere
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• v.21 no.4
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• pp.429-438
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• 2011

The climatology of surface UV radiation for Seoul, presented in Cho et al. (1998; 2001), has been updated using measurement of surface erythemal ultraviolet (EUV) and total ultraviolet (TUV) irradiance (wavelength 286.5~363.0 nm) by a Brewer Spectrophotometer (MK-IV) for the period 2004~2010. The analysis was also carried out together with the broadband total (global) solar irradiance (TR ; 305~2800 nm) and cloud amount to compare with the UV variations, measured by Seoul meteorological station of Korean Meteorological Agency located near the present study site. Under all-sky conditions, the day-to-day variability of EUV exhibits annual mean of 98% in increase and 31% in decrease. It has been also shown that the EUV variability is 17 times as high as the total ozone in positive change, whereas this is 6 times higher in negative change. Thus, the day to day variability is dominantly caused rather by the daily synoptic situations than by the ozone variability. Annual mean value of daily EUV and TUV shows $1.62kJm^{-2}$ and $0.63MJm^{-2}$ respectively, whereas mean value of TR is $12.4MJm^{-2}$ ($143.1Wm^{-2}$). The yearly maximum in noon-time UV Index (UVI) varies between 9 and 11 depending on time of year. The highest UVI shows 11 on 20 July, 2008 during the period 2004~2010, but for the period 1994~2000, the index of 12 was recorded on 13 July, 1994 (Cho et al., 2001). A 40% of daily maximum UVI belongs to "low (UVI < 2)", whereas the UVI less than 5% of the maximum show "very high (8 < UVI < 10)". On average, the maximum UVI exceeded 8 on 9 days per year. The values of Tropospheric Emission Monitoring Internet Service (TEMIS) EUV and UVI under cloud-free conditions are 1.8 times and 1.5 times, respectively, higher than the all-sky measurements by the Brewer. The trend analysis in fractional deviation of monthly UV from the reference value shows a decrease of -0.83% and -0.90% $decade^{-1}$ in the EUV and TUV, respectively, whereas the TR trend is near zero (+0.11% $decade^{-1}$). The trend is statistically significant except for TR trend (p = 0.279). It is possible that the recent UV decrease is mainly associated with increase in total ozone, but the trend in TR can be attributed to the other parameters such as clouds except the ozone. Certainly, the cloud effects suggest that the reason for the differences between UV and TR trends can be explained. In order to estimate cloud effects, the EUV, TUV and TR irradiances have been also evaluated for clear skies (cloud cover < 25%) and cloudy skies (cloud cover ${\geq}$ 75%). Annual mean values show that EUV, TUV and TR are $2.15kJm^{-2}$, $0.83MJm^{-2}$, and $17.9MJm^{-2}$ for clear skies, and $1.24kJm^{-2}$, $0.46MJm^{-2}$, and $7.2MJm^{-2}$ for cloudy skies, respectively. As results, the transmission of radiation through clouds under cloudy-sky conditions is observed to be 58%, 55% and 40% for EUV, TUV and TR, respectively. Consequently, it is clear that the cloud effects on EUV and TUV are 18% and 15%, respectively lower than the effects on TR under cloudy-sky conditions. Clouds under all-sky conditions (average of cloud cover is 5 tenths) reduced the EUV and TUV to about 25% of the clear-sky (cloud cover < 25%) values, whereas for TR, this was 31%. As a result, it is noted that the UV radiation is attenuated less than TR by clouds under all weather conditions.

• Journal of Bio-Environment Control
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• v.19 no.4
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• pp.360-365
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• 2010

The effects of precooling treatments on the storability of chicon were investigated during modified atmosphere (MA) storage. The forced air cooling showed faster precooling rate that reduced the internal temperature of chicon to $2{\pm}1^{\circ}C$, and the precooling time of forced air cooling was 1/6 of room cooling. The half cooling time was 3 hr 21 min in room cooling and 1 hr 17 min in forced air cooling. Weight loss was less than 0.5% in all treatments both $5^{\circ}C$ and $10^{\circ}C$ MA storage and maintained higher in forced air cooling treatment. The concentration of carbon dioxide, oxygen, and ethylene of $50{\mu}m$ ceramic film packages were observed higher at $10^{\circ}C$ than $5^{\circ}C$. The precooling effect on respiration reduction was not shown at $5^{\circ}C$, but appeared that the gas concentration of precooling treatments showed less carbon dioxide and higher oxygen than non precooling treatment by 9 days after $10^{\circ}C$ storage. Ethylene concentration of precooling treatments showed lower than non precooling treatment until 3 days both $5^{\circ}C$ and $10^{\circ}C$ MA storage. Precooling showed the effect on maintaining visual quality of chicon both $5^{\circ}C$ and $10^{\circ}C$ MA storage. However, the forced air cooling that showed faster precooling rate did not appeared more precooling effect on the visual quality than room cooling because the fast air flow (6.0 m/sec) of forced air cooling hit directly on chicon outer leaves and might cause physical damage to chicon. Although the forced air cooling showed the effect on maintaining quality of chicon, but additional studies should be needed that investigated proper air flow rate and cooling box structure can prevent physical damage by air flow.