• Proceedings of the Korean Environmental Health Society Conference
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• 2004.06a
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• pp.92-106
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• 2004

Elemental dry deposition fluxes were measured using dry deposition plates from March to June 1998 in Seoul, Korea. During this spring sampling period several yellow sand events characterized by long-range transport from China and Mongolia impacted the area. Understanding the impact of yellow-sand events on atmospheric dry deposition is critical to managing the heavy metal levels in the environment in Korea. In this study, the measured flux of a primarily crustal metal, Al and an anthropogenic metal, Pb was used with two hybrid receptor models, potential source contribution function (PSCF) and residence time weighted concentration (RTWC) for locating sources of heavy metals associated with atmospheric dry deposition fluxes during the yellow-sand events in Seoul, Korea. The PSCF using a criterion value of the 75th percentile of the measured dry deposition fluxes and RTWC results using the measured elemental dry deposition fluxes agreed well and consistently showed that there were large potential source areas in the Gobi Desert in China and Mongolia and industrial areas near Tianjin, Tangshan, and Shenyang in China. Major industrial areas of Shenyang, Fushun, and Anshan, the Central China loess plateau, the Gobi Desert, and the Alaskan semi-desert in China were identified to be major source areas for the measured Pb flux in Seoul, Korea. For Al, the main industrial areas of Tangshan, Tianjin and Beijing, the Gobi Desert, the Alashan semi-desert, and the Central China loess plateau were found to be the major source areas. These results indicate that both anthropogenic sources such as industrial areas and natural sources such as deserts contribute to the high dry deposition fluxes of both Pb and Al in Seoul, Korea during yellow-sand events. RTWC resolved several high potential source areas. Modeling results indicated that the long-range transport of Al and Pb from China during yellow-sand events as well as non yellow-sand spring daytimes increased atmospheric dry deposition of heavy metals in Korea.

• Asian-Australasian Journal of Animal Sciences
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• v.8 no.3
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• pp.205-212
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• 1995

This paper describes small ruminant production systems in dry areas of Pakistan. Formal and informal surveys had identified that poor feed resources, as a result of harsh climatic conditions, is a major factor responsible for low sheep and goats production. In view of their recommendations, use of approaches like supplemental feeding and pasture production through an introduction of improved forage species in the country, are reviewed. The improvement in sheep production and associated socioeconomic benefits, are discussed.

• Proceedings of the KSME Conference
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• 2001.06d
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• pp.189-194
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• 2001

A simultaneous visualization of the behavior of bubbles and dry spots has been carried out for pool boiling of R-1l3 on a horizontal heater. From video imaging and image processing analysis, the formation of bubbles and dry spots occurs simultaneously, and therefore they should be considered as a synchronized concept rather than independent identities. The dry spot density is equivalent to the active site density in the region before CHF. At CHF point, large dry areas due to the coalescence of neighboring dry areas cover the heater surface.

• Journal of Environmental Impact Assessment
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• v.18 no.6
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• pp.331-346
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• 2009

The serious problem facing two-dimensional finite element hydraulic model is the treatment of wet and dry areas. This situation is encountered in most practical river and coastal engineering problems, such as flood propagation, dam break analysis and so on. Especially, dry areas result in mathematical complications and require special treatment. The objective of this study is to investigate the wet and dry parameters that have direct relevance to model performance in situations where inundation of initially dry areas occurs. Several numerical simulations were carried out, which examined the performance of the marsh porosity method of RMA-2 model to investigate for application of parameters. Experimental channel with partly dry side slopes, straight channel with irregular geometry and Han river were performed for tests. As a result of this study, effectively applied marsh porosity method provide a reliable results for flow distribution of wet and dry area, it could be further developed to basis for extending to water quality and sediment transport analysis.

• Journal of The Korean Society of Grassland and Forage Science
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• v.10 no.3
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• pp.158-163
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• 1990

This experiment was to study the effect of pure mineral nitrogen fertilizing on seasonal distribution of dry matter yield and the advisable mineral nitrogen amounts on grassland. The results were as follows: 1. With longer regrowth periods the absolute dry matter yields and the nitrogen-efficiences due to nitrogen fertilizing increased substantially, whereas the quality declined at the relatively lesser cutting frequencies. 2. The first cut at 3-cut regimes, the first and fourth cut at 4-cut regimes, and the second and last cut at 5-and 6-cut regimes showed the highest nitrogen-efficiency, respectively. 3. By the sigmaformed process of production curve the most efficient mineral N-dressing rate per ha and cut was calculated: 42-56kg N on the 3-cut areas, 39-55kg N on the 4-cut areas, 38-47kg N on the 5-cut areas and 35-48kg N/ha/cut on the &cut areas. 4. In dependence on site and kind of calculation the economical borders were reached with the following dressings of mineral N/ha/cut: 90-100kg on the 3-cut areas, 70-100kg on the 4-cut areas and 50- 90kg on the 5-and 6-cut areas.

• Proceedings of the Korea Water Resources Association Conference
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• 2009.05a
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• pp.827-831
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• 2009

Recently, frequency occurring flood and drought has increased the necessity of an effective water resources control and management of river flows. Therefore, the simulation of the flow distribution in natural rivers is great importance to the solution of a wide variety of practical flow problems in water resources engineering. However The serious problem facing two-dimensional hydraulic model is the treatment of wet and dry areas. The objective of this study is to investigate the wet and dry parameters that have direct relevance to model performance in situations where inundation of initially dry areas occurs. Several numerical simulations were carried out, which examined the performance of the marsh porosity method for the purpose of sensitivity analysis. Experimental channel and a variety of channel were performed for model tests. The results were compared with those of the observation data and simulation data of existing model. The RMA-2 model displayed reasonable flow distribution compare to the observation data and simulation data of existing model in dry area for application of natural river flow. As a result of this study, effectively applied marsh porosity method provide a reliable results for flow distribution of wet and dry area, it could be further developed to basis for extending to water quality and sediment transport analysis.

• Journal of Environmental Science International
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• v.10 no.1
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• pp.1-8
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• 2001

This study was carried out estimating the dry deposition flux of $SO_2$at eight urban areas in Korea during one year of 1996. To calculate the deposition flux, deposition velocities were calculated by turbulence parameters estimated from routine meteorological data. Also, hourly averaged $SO_2$concentrations which calculated from air pollution monitoring data of each city were used. The dry deposition velocities were mostly higher in the coastal areas than the other areas, which would be caused by relatively strong wind. And, they were high in the daytime because of turbulence activities. The deposition flux of $SO_2$is mainly related to the atmospheric concentration. The annual average $SO_2$concentration and the deposition flux were 22.62ppb and 1510.52g/$\textrm{km}^2$/hr at Pusan respectively. Also, the flux was higher in winter than other season, which was a significant contribution of exhausted fuel for heating. While the deposition velocity was high to 0.688cm/sec at Yosu in case of strong wind and small cloud cover, the deposition flux was high to 1597.4g/$\textrm{km}^2$/hr at Pusan in case of weak wind and small cloud cover.

• Journal of The Korean Society of Grassland and Forage Science
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• v.14 no.3
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• pp.201-205
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• 1994

The objectives of this research are to determine the seasonal and varietal differences of total digestible nutrients(TDN) and in vitro dry matter digestibility(1VDMD) of tall fescue grown in Takwalyon areas, based on the data of preceding paper(Lee et al. 1994b). The results are may be summarized as follows : 1. The values of total digestible nutrients(TDN) and in vitro dry matter digestibility(1VDMD) in 1st cutting were lower than the values of 2nd and 3rd cutting, and it was due to different stages of growth and seasonal difference of climatic conditions in this areas. 2. The relative yield(RY) had negative significantly correlation with in vitm dry matter digestibility(1VDMD) of 1st cutting. 3. Total digestible nutrients(TDN) indicated high positive significant correlation with in vitro dry matter digestility (IVDMD) in all cuttings. 4. The variety of Johnstone showed a high values of total digestible nutrients(TDN) and in vitm dry matter digestibility(1VDMD) of 2nd and 3rd cutting, but Fuego was lower than the other varieties.

• Journal of the Korean Society of Tobacco Science
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• v.11 no.2
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• pp.115-126
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• 1989

This study was conducted to determine the time and methods of predicting tobacco yield, by studying the relationship of yield components to yield. 1. The relationship between each position in leaf dry weight and approached gradually each other and also correlation coefficient of top leaf was higher than that of lower leaf. The leaf dry weight per plant was highly correlated with leaf area from 16th leaf position on stalk. Leaf dry weight of each leaf position on stalk was highly correlated with leaf dry weight per plant at 14 to 16th leaf position. 2. The correlation coefficient between leaf dry weight and leaf area per plant was higher at the late growth stage than at the early growth stage, and higher between the near stages. Correlation coefficient between leaf dry weights was higher than that of leaf areas. 3. Flue-cured tobacco yield be estimated from leaf dry weight per plant at 50 to 55 days after transplanting. 4. Air-cured tobacco yield could be predicted from leaf dry weight per plant at 60 days after transplanting.

• Journal of Wetlands Research
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• v.10 no.2
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• pp.105-114
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• 2008

Growth in population and urbanization has progressively increased the loadings of pollutants from non-point sources as well as point sources. Separated sewer overflows(SSO) have been considered as a major cause of water-quality deterioration of natural water-courses in the vicinity of the heavily urbanized areas. The factors defining the magnitude and occurrence of SSO are site-specific. It is important to know exact properties of pollutants contained in SSO to address water quality impacts that are caused by SSO inputs to the receiving waters. Site and event parameters found to have significant influences on urban runoff pollutant EMCs include total event rainfall, antecedent dry period, rainfall intensity. In this study, a field survey was carried out in some selected areas of Cheongju city. Literature from previous similar studies was consulted and some important factors affecting the runoff characteristics of urban drainage areas were analyzed for some selected survey points. It was found that the factors most affecting BOD are the number of dry days prior to rainfall and the intensity of the rainfall. The factor most affecting CODcr is the number of dry days prior to rainfall. The factors most affecting SS are the amount of rainfall and the number of dry days prior to rainfall. The factor most affecting TN is the amount of rainfall. The factor most affecting TP is the amount of rainfall and the number of dry days prior to rainfall.