• Journal of the Korean earth science society
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• v.21 no.5
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• pp.611-622
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• 2000

To investigate the exchange rates of mercury(Hg) across soil-air boundary, we undertook the measurements of Hg flux using gradient technique from a major waste reclamation site, Nan-Ji-Do. Based on these measurement data, we attempted to provide insights into various aspects of Hg exchange in a strongly polluted soil environment. According to our analysis, the study site turned out to be not only a major emission source area but also a major sink area. When these data were compared on hourly basis over a full day scale, large fluxes of emission and deposition centered on daytime periods relative to nighttime periods. However, when comparison of frequency with which emission or deposition occurs was made, there emerged a very contrasting pattern. While emission was dominant during nighttime periods, deposition was most favored during daytime periods. When similar comparison was made as a function of wind direction, it was noticed that there may be a major Hg source at easterly direction to bring out significant deposition of Hg in the study area. To account for the environmental conditions controlling the vertical direction of Hg exchange, we compared environmental conditions for both the whole data group and those observed from the wind direction of strong deposition events. Results of this analysis indicated that the concentrations of pollutant species varied sensitively enough to reflect the environmental conditions for each direction of exchange. When correlation analysis was applied to our data, results indicated that windspeed and ozone concentrations best reflected changes in the magnitudes of emission/deposition fluxes. The results of factor analysis also indicated the possibility that Hg emission of study area is temperature-driven process, while that of deposition is affected by a mixed effects of various factors including temperature, ozone, and non-methane HCs. If the computed emission rate is extrapolated to the whole study area we estimate that annual emission of Hg from the study area can amount to approximately 6kg.

• Journal of the Korean earth science society
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• v.34 no.3
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• pp.209-223
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• 2013

The purpose of this study was to estimate the contributed concentration of each emission source to $CH_4$ by verifying the simulated concentration of $CH_4$ in the Korean peninsula, and then to compare the $CH_4$ emission used to the $CH_4$ simulation with that of a box model. We simulated the Weather Research Forecasting-Community Multiscale Air Quality (WRF-CMAQ) model to estimate the mean concentration of $CH_4$ during the period of April 1 to 22 August 2010 in the Korean peninsula. The $CH_4$ emissions within the model were adopted by the anthropogenic emission inventory of both the EDGAR of the global emissions and the GHG-CAPSS of the green house gases in Korea, and by the global biogenic emission inventory of the MEGAN. These $CH_4$ emission data were validated by comparing the $CH_4$ modeling data with the concentration data measured at two different location, Ulnungdo and Anmyeondo in Korea. The contributed concentration of $CH_4$ estimated from the domestic emission sources in verification of the $CH_4$ modeling at Ulnungdo was represented in about 20%, which originated from $CH_4$ sources such as stock farm products (8%), energy contribution and industrial processes (6%), wastes (5%), and biogenesis and landuse (1%) in the Korean peninsula. In addition, one that transported from China was about 9%, and the background concentration of $CH_4$ was shown in about 70%. Furthermore, the $CH_4$ emission estimated from a box model was similar to that of the WRF-CMAQ model.

• Journal of Bio-Environment Control
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• v.29 no.1
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• pp.43-51
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• 2020

For developing a canopy photosynthesis model, an efficient method to measure the photosynthetic rate in a growth chamber is required. The objective of this study was to develop a method for establishing canopy photosynthetic rate curves of romaine lettuce (Lactuca sativa L.) with light intensity and CO₂ concentration variables using controlled growth chamber. The plants were grown in plant factory modules, and the canopy photosynthesis rates were measured in sealed growth chambers made of acrylic (1.0 × 0.8 × 0.5 m). First, the canopy photosynthetic rates of the plants were measured, and then the time constants were compared between two application methods: 1) changing light intensity (340, 270, 200, and 130 μmol·m^-2·s^-1) at a fixed CO₂ concentration (1,000 μmol·mol^-1) and 2) changing CO₂ concentration (600, 1,000, 1,400, and 1,800 μmol·mol^-1) at a fixed light intensity (200 μmol·m^-2·s^-1). Second, the canopy photosynthetic rates were measured by changing the light intensity at a CO₂ concentration of 1,000 μmol·mol^-1 and compared with those measured by changing the CO₂ concentration at a light intensity of 200 μmol·m^-2·s^-1. The time constant when changing the CO₂ concentration at the fixed light intensity was 3.2 times longer, and the deviation in photosynthetic rate was larger than when changing the light intensity. The canopy photosynthetic rate was obtained stably with a time lag of one min when changing the light intensity, while a time lag of six min or longer was required when changing the CO₂ concentration. Therefore, changing the light intensity at a fixed CO₂ concentration is more appropriate for short-term measurement of canopy photosynthesis using a growth chamber.

• Journal of Plant Biotechnology
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• v.32 no.1
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• pp.23-29
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• 2005

Shoots of balloon flower (Platycodon grandiflorum A. DC.) derived from in vitro germinated seeds were cultured on MS medium containing $0.1\;\cal{mg/L}$ NAA under various photosynthetic photon flux (PPF) 33, 66, and $99\;{\mu}mol\;m^{-2}s^{-1}$ with or without membrane filter. Number of air exchanges per hour (NAEH) of the culture vessel with membrane filter on the lid was $4.9 h^{-1}$ and that without membrane filter was $0.1 h^{-1}$ Plantlets grown in $4.9 h^{-1}$ NAEH showed greater growth than in $0.1 h^{-1}$ NAEH. According to increase of PPF, plantlets growth decreased in $0.1 h^{-1}$ NAEH while it increased in $4.9 h^{-1}$ NAEH. At the same PPF, fresh weight and sugar content in plantlets in $4.9 h^{-1}$ NAEH were above 1.9, 2.0 times higher than those in $0.1 h^{-1}$ NAEH, respectively. Also they were enhanced in $4.9 h^{-1}$ NAEH by increase of PPF whereas no significance in $0.1 h^{-1}$ NAEH. The percentage of water content of plantlets in $4.9 h^{-1}$ NAEH was $4.2\~5.5\%$ lower than those in $0.1 h^{-1}$ and no difference in PPF. The content of total chlorophyll in plantlets in $4.9 h^{-1}$ NAEH was higher $0.27\~0.79\;\cal{mg/g}$ F.W. than that in $0.1 h^{-1}$ NAEH. By increase of PPF, it was decreased in $0.1 h^{-1}$ NAEH while had no significant difference in $4.9 h^{-1}$ NAEH. Guard and subsidiary cells of leaves in $4.9 h^{-1}$ NAEH were more developed than in $0.1 h^{-1}$ NAEH. Especially, in $99\;{\mu}mol\;m^{-2}s^{-1}$ leaves in $0.1 h^{-1}$ NAEH had undeveloped subsidiary cells and wide open stomata whereas those in $4.9 h^{-1}$ NAEH had well-developed subsidiary cells.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.19 no.2
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• pp.131-146
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• 2014

High-resolution seismic profiles coupled with sediment sampling were analyzed to investigate the acoustic characters and distribution patterns of the late Holocene sediments in Gamak Bay of the South Sea, Korea. The mean grain size of surficial sediment lies around $6.3{\sim}9.7{\Phi}$. Sediments in the bay consist of silt and clay with progressive decrease toward the inner bay. The seismic sedimentary sequence overlying the acoustic basement can be divided into two sedimentary units (GB I and II) by a prominent mid-reflector (Maximum Flooding Surface; MFS). The acoustic basement occurs at the depth between 20 m and 40 m below the sea-level and deepens gradually southward. The GB I, mostly occupying the channel-fill, is characterized by reflection-free seismic facies. It can be formed as late Transgressive System Tract (TST), interpreted tidal environment deposits. MFS appears at the depth of about 15~28 m below the sea-level and is well defined by even and continuous reflectors on the seismic profile. The GB II overlying MFS is composed of acoustically transparent to semitransparent and parallel internal reflectors. GB II is interpreted as the Highstand System Tract (HST) probably deposited during the last 6,000 yrs when the sea level was close to the present level. Especially, it is though that the GB II was subdivided into two layers (GB II-a and II-b) by a HST-reflector and this was classified by wind, sea water flux, and tidal current.

• Korean Journal of Agricultural and Forest Meteorology
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• v.17 no.4
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• pp.358-383
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• 2015

The concept of 'carbon footprint' has been developed as a means of quantifying the specific emissions of the greenhouse gases (GHGs) that cause global warming. Although there are still neither clear definitions of the term nor rules for units or the scope of its estimation, it is broadly accepted that the carbon footprint is the total amount of GHGs, expressed as $CO_2$ equivalents, emitted into the atmosphere directly or indirectly at all processes of the production by an individual or organization. According to the ISO/TS 14067, the carbon footprint of a product is calculated by multiplying the units of activity of processes that emit GHGs by emission factor of the processes, and by summing them up. Based on this, 'carbon labelling' system has been implemented in various ways over the world to provide consumers the opportunities of comparison and choice, and to encourage voluntary activities of producers to reduce GHG emissions. In the agricultural sector, as a judgment basis to help purchaser with ethical consumption, 'low-carbon agricultural and livestock products certification' system is expected to have more utilization value. In this process, the 'cradle to gate' approach (which excludes stages for usage and disposal) is mainly used to set the boundaries of the life cycle assessment for agricultural products. The estimation of carbon footprint for the entire agricultural and forestry sector should take both removals and emissions into account in the "National Greenhouse Gas Inventory Report". The carbon accumulation in the biomass of perennial trees in cropland should be considered also to reduce the total GHG emissions. In order to accomplish this, tower-based flux measurements can be used, which provide a direct quantification of $CO_2$ exchange during the entire life cycle. Carbon footprint information can be combined with other indicators to develop more holistic assessment indicators for sustainable agricultural and forestry ecosystems.

• Korean Journal of Agricultural and Forest Meteorology
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• v.9 no.3
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• pp.188-194
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• 2007

The relationships between pine mushroom emergence and meteorological factors were analyzed with three years (from 2003 to 2005) of measurement data at Yangyang site, in order to evaluate the effect of micrometeorological environment on pine mushroom production. fine mushroom was daily monitored and collected in the survey area during the its producing period (approximately one month). Pine mushroom production was highest in 2005 with the meteorological conditions of high temperature and frequent rainfalls in October. The production was lowest in 2004 due to dry conditions from mid September to late October, The meterological factors related to humidity (i.e., relative humidity, soil water content, and precipitation) were better correlated than those related to temperature (i.e., air and soil temperature, soil heat flux and solar radiation) with pine mushroom production. However, all of the correlation coefficients were statistically insignificant with values ranging from 0.15 to 0.46. Such poor correlations may be attributed to various other environmental conditions (e.g., topography, soil, vegetation, other fungi, the relationship between pine mushroom and pine forest) affecting pine mushroom production. We found that a mycelium requires a stimulation of low temperature (of three-day moving average) below $19.5^{\circ}C$, in order to farm a mushroom primordium which grows to pine mushroom after 16 days from the stimulation. We also found that the pine mushroom production ended when the soil temperature (of three-day moving average) fell below $14.0^{\circ}C$.

• Korean Journal of Agricultural and Forest Meteorology
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• v.13 no.2
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• pp.69-78
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• 2011

Rice is one of the world's staple foods. Paddy rice fields have unique biophysical characteristics that the rice is grown on flooded soils unlike other crops. Information on the spatial distribution of paddy fields and the timing of irrigation are of importance to determine hydrological balance and efficiency of water resource management. In this paper, we detected the timing of irrigation and spatial distribution of paddy fields using the Moderate Resolution Imaging Spectroradiometer (MODIS) sensor onboard the NASA EOS Aqua satellite. The timing of irrigation was detected by the combined use of MODIS-based vegetation index and Land Surface Water Index (LSWI). The detected timing of irrigation showed good agreement with field observations from two flux sites in Korea and Japan. Based on the irrigation detection, a land cover map of paddy fields was generated with subsidiary information on seasonal patterns of MODIS enhanced vegetation index (EVI). When the MODISbased paddy field map was compared with a land cover map from the Ministry of Environment, Korea, it overestimated the regions with large paddies but underestimated those with small and fragmented paddies. Potential reasons for such spatial discrepancies may be attributed to coarse pixel resolution (500 m) of MODIS images, uncertainty in parameterization of threshold values for discarding forest and water pixels, and the application of LSWI threshold value developed for paddy fields in China. Nevertheless, this study showed that an improved utilization of seasonal patterns of MODIS vegetation and water-related indices could be applied in water resource management and enhanced estimation of evapotranspiration from paddy fields.

• Journal of Astronomy and Space Sciences
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• v.24 no.1
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• pp.55-68
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• 2007

We carried out a validation study on AURIC FUV/EUV dayglow calculation with $OII\;834{\AA},\;OI\;989{\AA},\;OI\;1027{\AA},\;NII\;1085{\AA},\;NI\;1134{\AA},\;NI\;1200{\AA},\;OI\;1304{\AA},\;OI\;1356{\AA}$ dayglows observed by STP78-1 satellite. Comparison between calculated and observed values indicates that they are in agreement within about 20% for dayglows of $OII\;834{\AA},\;OI\;1027{\AA},\;NI\;1200{\AA},\;OI\;1304{\AA}$. However, the calculated intensities of $OI\;989{\AA},\;NII\;1085{\AA},\;NI\;1134{\AA}$ are only 42, 74 and 45% of the observed values, respectively, showing serious differences from the observation. It was surmised that the differences in $OI\;989{\AA}\;and\;NI\;1134{\AA}$ are due to incomplete calculation of radiative transfer and uncertain photochemical processes in AURIC model, respectively. The difference in $NII\;1085{\AA}$ is conjectured to be due to variation of the input solar EUV flux rather than due to AURIC model itself. For up-looking dayglows from the satellite, the calculated values from AURIC are all less than those of STP78-1, which may imply that AURIC model does not include dayglow contribution from regions below the satellite altitude when it computes dayglows in up-looking direction. The differences are particularly serious for $OI\;989{\AA},\;NI\;1134{\AA},\;NI\;1200{\AA}$ dayglows. The calculated latitudinal variation of $OII\;834{\AA}$ dayglow is also significantly different from the observed one, especially at mid-latitude regions. This may be due to inability of MSISE-90 (in input of AURIC) to simulate oxygen atom densities at mid-latitudes during auroral storms at those days of STP78-1 observations. Our findings of the validation study should be resolved when AURIC model is revised in future.

• Journal of Nutrition and Health
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• v.41 no.5
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• pp.381-390
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• 2008

Present study was conducted to investigate the effects of exercise and cholesterol diet on plasma and liver lipids, platelet aggregation, erythrocyte Na efflux and liver index such as GOT and GPT using Sprague Dawley rats. Forty rats were divided into four groups and fed control or 0.5% cholesterol diet with and without treadmill for six weeks. The final body weight of group fed cholesterol diet with exercise was somewhat decreased compared with group fed cholesterol diet without exercise. L.W/B.W ratio was significantly increased in groups fed cholesterol diet (p < 0.01), but exercise tended to decrease this ratio. Plasma total cholesterol was significantly increased and HDL-cholesterol was decreased in groups fed cholesterol diet (p < 0.01). Plasma triglyceride was significantly decreased in groups fed cholesterol diet compared with groups fed control diet (p < 0.01). Plasma triglyceride of groups with exercise was significantly decreased compared with their non exercising counterparts regardless diet (p < 0.05). Liver total cholesterol and triglyceride was significantly increased in groups fed cholesterol diet (p < 0.01), but exercise did not affect on these levels. Na-K ATPase was somewhat decreased in groups fed cholesterol diet, and exercise tended to recover the reduced Na-K ATPase. Na passive transport was significantly decreased in group fed control diet without exercise and significantly increased in group fed cholesterol diet with exercise, there were significant differences between groups (p < 0.05). There were no differences in total Na efflux and intracellular Na among groups, and total Na efflux was not correlated with intracellular Na. Hematocrit was significantly lower (p < 0.05) in group fed cholesterol diet without exercise compared with other groups. Platelet aggregation in the initial slope and the maximum was increased in groups fed cholesterol diet, but not statistically significant. Exercise especially increased the initial slope of aggregation. Plasma GOT and GPT was significantly increased in groups fed cholesterol diet (p < 0.01), and exercise in group fed cholesterol diet significantly decreased both GOT and GPT compared with the non exercising counterpart (p < 0.01). This study showed that cholesterol diet increases plasma and liver lipids and GOT and GPT, and exercise improves plasma and liver lipid profile and liver index of GOT and GPT preventing fatty liver.