• Journal of Biosystems Engineering
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• v.12 no.2
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• pp.16-27
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• 1987

Greenhouse farming was introduced to the Korean farmers in the middle of 1950's and its area has been increased annually. The plastic greenhouse, which is covered with polyethylene or polyvinyl chloride film, has been rapidly spread in greenhouse farming since 1970. The greenhouse farming greatly contributed to the increase of farm household income and the improvement of crop productivity per unit area. Since the greenhouse farming is generally practiced during winter, from November to March, the thermal environment in the plastic greenhouse should be controlled in order to maintain favorable condition for plant growing. Main factors that influence the thermal environment in the plastic greenhouse are solar radiation, convective and radiative heat transfer among the thermal component of the greenhouse, and the use of heat source. The objective of this study was to develop a simulation model for thermal environment of the plastic greenhouse in order to determine the characteristics of heat flow and effects of various ambient environmental conditions upon thermal environments within the plastic greenhouse. The results obtained are summarized as follows: 1. Simulation model for thermal environment of the plastic greenhouse was developed, resulting in a good agreement between the experimental and predicted data. 2. Solar radiation being absorbed in the plant and soil during the daytime was 75 percent of the total solar radiation and the remainder was absorbed in the plastic cover. 3. About 83 percent of the total heat loss was due to convective and radiative heat transfer through the plastic cover. Air ventilation heat loss was 5 to 6 percent of total heat loss during the daytime and 16 to 17 percent during the night. 4. The effectiveness of thermal curtain for the plastic greenhouse at night was significantly increased by the increase of the inside air temperature of the greenhouse due to the supplementary heat. 5. When the temperature difference between the inside and outside of the greenhouse was small, the variation of ambient wind velocity did not greatly affect on the inside air temperature. 6. The more solar radiation in the plastic greenhouse was, the higher the inside air temperature. Because of low heat storage capacity of the plant and soil inside the greenhouse and a relatively high convective heat loss through the plastic cover, the increase of solar radiation during the daytime could not reduce the supplymentary heat requirement for the greenhouse during the night.

• Korean Chemical Engineering Research
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• v.52 no.6
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• pp.807-813
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• 2014

The Ag-impregnated activated carbon was produced from bamboo activated carbon by soaking method of silver nitrate solution. The carbonization and activation of raw material was conducted at $900^{\circ}C$. Soaking conditions are the variation of silver nitrate solution concentration (0.002~0.1 mol/L) and soaking time (maximum 24 h). The specific surface area and pore size distribution of the prepared activated carbons were measured. Also, NO and activated carbon reaction were conducted in a thermogravimetric analyzer in order to use for de-NOx agents of used activated carbon. Carbon-NO reactions were carried out with respect to reaction temperature ($20{\sim}850^{\circ}C$) and NO gas partial pressure (0.1~1.8 kPa). As results, Ag amounts are saturated within 2h, Ag amounts increased 1.95 mg Ag/g (0.2%)~ 88.70 mg Ag/g (8.87%) with the concentration of silver nitrate solution in the range of 0.002~0.1 mol/L. The specific volume and surface area of bamboo activated carbon of impregnated with 0.2% silver were maximum, but decreased with increasing Ag amounts of activated carbon due to pore blocking. In NO reaction, the reaction rate of impregnated bamboo activated carbon was retarded as compare with that of bamboo activated carbon. Measured reaction orders of NO concentration and activation energy were 0.63[BA], 0.69l[BA(Ag)] and 80.5 kJ/mol[BA], 66.4 kJ/mol[BA(Ag)], respectively.

• The Journal of Engineering Geology
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• v.13 no.1
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• pp.29-50
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• 2003

Physicochemical Properties of acid mine water of the Chonam-ri Creek and the Sagok-ri Creek in the Kwangyang Au-Ag mine area were determined using geochemical approaches. Metal contamination (Cd, Cu, Pb, Zn) is more serious in the Chonam-ri Creek than in the Sagok-ri Creek. However, the contents of Al and Fe is higher in the Sagok-ri Creek. Such differences between the two creeks probably reflect the abundance and composition of ore minerals. The attenuation processes for acid mine water in both creeks were investigated. In the Chonam-ri Creek, a small retention pond which contains limestone plays an important role in the removal of heavy metals by adsorption or coprecipitation due to increase of pH. The capacity of metal scavenging in this pond depends on the seasonal variation of inflow volume. Reddish yellow precipitates sampled in the Chonam-ri Creek were analyzed by XRD, SEM-EDS, EPMA, and chemical decomposition. The precipitates mainly consist of goethite and are also enriched in Al, Mn, Cu and Zn. This inditates that precipitation of goethite is important for scavenging those trace elements, possibly due to adsorption or coprecipitation. In the Sagok-ri Creek, on the other hand, hydrologic mixing of uncontaminated tributaries results in removal of heavy metals with iron hydroxides precipitation due to the pH increase. The mechanisms proposed for metal attenuation at the confluence between contaminated mine water and uncontaminated tributary water are also explained by the property-property plots.

• Journal of Korea Water Resources Association
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• v.51 no.2
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• pp.121-129
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• 2018

Rainfall falling in the impervious area of the cities flows over the surface and into the stormwater pipe networks to be discharged from the catchment. Therefore, it is very important to determine the size of stormwater pipes based on the peak discharge to mitigate urban flood. Climate change causes the severe rainfall in the small area, then the peak rainfall can not be discharged due to the capacity of the stormwater pipes and causes the urban flood for the short time periods. To mitigate these type of flood, the large stormwater pipes have to be constructed. However, the economic factor is also very important to design the stormwater pipe networks. In this study, 4 urban catchments were selected from the frequently flooded cities. Rainfall data from Seoul and Busan weather stations were applied to calculate runoff from the catchments using SWMM model. The characteristics of the peak runoff were analyzed using linear regression model and the 95% confidence interval and the coefficient of variation was calculated. The drainage density was calculated and the runoff characteristics were analyzed. As a result, the drainage density were depended on the structure of stormwater pipe network whether the structures are dendritic or looped. As the drainage density become higher, the runoff could be predicted more accurately. it is because the possibility of flooding caused by the capacity of stormwater pipes is decreased when the drainage density is high. It would be very efficient if the structure of stormwater pipe network is considered when the network is designed.

• Journal of Bio-Environment Control
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• v.5 no.2
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• pp.187-193
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• 1996

This experiment was conducted to investigate the influence of temperature variation by the different ventilation methods on the growth and quality of oriental melon in greenhouse of tunnel type 1. The dropping effect in temperature by ventilation types was best at type 3 and those of type 2, type 1 were in order. 2. The temperature distribution in type 3 was uniformed as air- inflow and air- outflow by wind ventilation were easier than others. Whereas the temperature of type 1 having lateral ventilation hole and type 2 having the zenith ventilation tube and lateral ventilation hole was ascended, because small ventilation area of ventilation tube and hole could not make the gravity and wind ventilation successfully. 3. When compared with air amount of three types ventilated by the temperature difference of outside and inside of tunnel type house, that of type 3 was more than those of type 1 and type 2. 4. Type 3 was better than type 2 and type 1 in lear numbers, leaf area, fruit weight, flesh thickness, malformed fruit rate, and marketable fruit rate. 5. Marketable fruit rate of all treatment at each harvesting stages was rised, as goes to the latter periods.

• Korean Journal of Ichthyology
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• v.22 no.4
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• pp.230-237
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• 2010

Histological observation on the seasonal variation of mucus cells of the mud loach Misgurnus mizolepis inhabiting a natural stream was carried out on three skin regions (dorsal, lateral and occiput) from March 2008 to February 2009. Our results showed no differences in general morphology by season, but the mucus cells of the epidermis showed significant seasonal change in their size and number as the water temperature changed. The ratio of surface area of the mucus cell layer and mucus cells, and the number of mucus cells in surface area of the epidermis were the greatest in the cold winter and the least in the hot summer in all regions of the epidermis. In particular, the occiput seemed to be a very sensitive region in response to environmental change, showing wide fluctuations in the size of mucus cells throughout the year and a great change in between seasons, especially from late autumn to early winter when the temperature decreased. As the temperature became colder, a small and spherical-shaped mucus cell was transformed into a large and elongated columnar form with a lot of secreted mucus material in a superficial layer of the epidermis. From our results, we can safely surmise that cold temperature is an important environmental factor having a close relationship with the modification of mucus cells of M. mizolepis in winter.

• Economic and Environmental Geology
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• v.30 no.1
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• pp.35-49
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• 1997

The coal formation of the Deokpyeong area are interbedded along metapelites of the Ogcheon Supergroup, which are composed mainly of graphite, quartz, muscovite and associated with small amounts of biotite, chlorite, pyrite and barite. The ratios of $SiO_2/Al_2O_3$, $Al_2O_3/Na_2O$ and $K_2O/Na_2O$ of the coaly metapelite are variable and wide range from 1.80 to 10.21, from 27.8 to 388.8 and from 7.6 to 61.8, respectively. These coal formation were deposited in basin of marine environments, and the REE of these rocks are not influenced with metamorphism and hydrothermal alterations on the basis of $Al_2O_3$ versus La, La against Ce, the ratios of La/Ce (0.19 to 0.99) and Th/U (0.02 to 4.75). These rocks also show much variation in $La_N/Yb_N$ (1.19 to 22.89), Th/Yb (0.14 to 21.43) and La/Th (0.44 to 13.67), and their origin is explained by derivation from a mixture of sedimentary and igneous rocks. The wide range in trace and REE element characteristics as Co/Th (0.12 to 2.78), La/Sc (0.33 to 10.18), Sc/Th (0.57 to 5.73), V/Ni (8 to 2347), Cr/V (0.02 to 0.67) and Ni/Co (1.56 to 32.95) of these coaly metapelites argues for inefficient mixing of the various source lithologies during sedimentation. Deep to pale green barium-vanadium muscovites (vanadium-oellacherite) have been found in this coal formations. Modes of occurrence and grain size of muscovite are heterogeneous, but most of the barium and vanadium-bearing muscovites occur along the boundaries between graphite and quartz grains, ranging from 200 to $350{\mu}m$ in length and from 40 to $60{\mu}m$ in width. Results of X-ray diffraction data of the minerals characterized to be monoclinic system with $a=5.249{\AA}$, $b=8.939{\AA}$, $c=20.924{\AA}$ and ${\beta}=95.894^{\circ}$. Representative chemical formula of the muscovite was $(Na_{0.09}K_{1.44}Ba_{0.46})(Al_{2.75}Ti_{0.07}V_{0.56}Fe_{0.08}Mg_{0.50})(Si_{6.12}Al_{1.88})O_{22}$. The V possibly substitute octahedral Al, and the Ba is coupled substitution of $K^+Si^{4+}=Ba^{2+}Na^+Ca^{2+}$, which compositional ranges of V and Ba are from 0.42 to 0.69 and from 0.34 to 0.56 based on $O_{22}$, respectively. Formation mechanism of the barium-vanadium muscovites in the coaly metapelite is shown that the formed by high pressure and temperature from regional metamorphism origanated during diagenesis at the interface between a basinal brine and organic matter.

• Korean Journal of Medicinal Crop Science
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• v.13 no.1
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• pp.30-34
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• 2005

Polygonatum species are a useful medical crop in Korea but basic study in the species was not well conducted. The study was carried out to analyse genetic diversity and intraspecific relationship of 47 Polygonatum species collected from Gyeongnam province. Their analysis was done through principle component analysis and average linkage cluster analysis with their twelve morphological traits. The result of principle component analysis showed the Prin 1, Prin 2 and Prin 3 represented 79% of total variation. By the 0.7 average distance of the cluster analysis and the calculated Euclidian distance, the 47 collected species were grouped into five groups. Group I included 22 collected species representing P. ordoratum var. pluriflorum, group II did 5 ones representing P. involucratum, group III was divided into two subclasses, 2 species including P. inflatum and 7 species including P. thunbergii, group IV also consisted of 2 subclasses, a species similar to P. thunbergii and P.involucratum, respectively, and finally group V included 8 species representing P.lasianthum var. coreanum. meaning that the useful germplasms can be collected from relatively small area.

• Journal of the Korean Association of Geographic Information Studies
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• v.10 no.4
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• pp.60-74
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• 2007

For quantitative analysis of spatio-temporal distribution pattern on marine environment, spatial autocorrelation statistics on the both global and local aspects was applied to the observed data obtained from Gwangyang Bay in South Sea of Korea. Global indexes such as Moran's I and General G were used for understanding environmental distribution pattern in the whole study area. LISAs (local indicators of spatial association) such as Moran's I ($I_i$) and $G_i{^*}$ were considered to find similarity between a target feature and its neighborhood features and to detect hot spot and/or cold spot. Additionally, the significance test on clustered patterns by Z-scores was carried out. Statistical results showed variations of spatial patterns quantitatively in the whole year. Then all of general water quality, nutrients, chlorophyll-a and phytoplankton had strong clustered pattern in summer. When global indexes showed strong clustered pattern, the front region with a negative $I_i$ which means a strong spatial variation was observed. Also, when global indexes showed random pattern, hot spot and/or cold spot were/was found in the small local region with a local index $G_i{^*}$. Therefore, global indexes were useful for observing the strength and time series variations of clustered patterns in the whole study area, and local indexes were useful for tracing the location of hot spot and/or cold spot. Quantification of both spatial distribution pattern and clustering characteristics may play an important role to understand marine environment in depth and to find the reasons for spatial pattern.

• Archives of Reconstructive Microsurgery
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• v.16 no.2
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• pp.113-118
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• 2007

Purpose: The purpose of this work was to describe the results of treatment for motor vehiclerelated crushing injuries among children and adolescents under sixteen years in Korea. Materials and Methods: A retrospective analysis was conducted of data from children who were under sixteen year and injured foot by motor vehicles. Cases were documented 1) age at the time of injury, 2) injured site, 3) the area of accident, 4) the kind of vehicle, 5) associated injuries, 6) methods of treatment for soft tissue reconstruction and 7) complications. The relationships between the area of accident and associated injuries, and the kind of vehicle and associated injuries were analyzed using Chi-square test and Fisher exact test. Results: There were 97 children who were 15 year and younger. The mean age was 7.4 years, and 65% were boys. The left foot was more dominant side of injury (57%). Seasonal variation was seen with the number of injuries peaking during the summer (43%, p<0.05). Among the vehicles, 78.3% were the large vehicles (bus, truck or van). The where of accident was more frequent at an alley or less than two lanes of traffic. But, the relationships between the place of accident and associated injury or the kind of vehicles and associated injury were not statistically significant. The associated injury were fracture or dislocation (23 cases, 35.9%), injury of tendon (21 cases, 32.8%). There were amputation or disarticulation of foot in 8 cases (8.2%) and post-traumatic deformities such as flatfoot, hindfoot varus or valus deformities by tendon injury in 7 cases (7.2%). Conclusion: More than 50% of crushing or degloving injuries of child's foot by traffic accidents happened in boys between 5 to 9 years old. The associated injury was unrelated with size of vehicles or accident place at the time of accident. But, even though foot injury happened in an alley or one lane by small vehicles, child who hurt feet by car need thorough investigation about associated injury. If a surgeon keep in mind and treat child to associated injury necessarily, can minimize complication. Microsurgical reconstruction for soft tissue defect was prior to other methods.