• Korean Journal of Food Science and Technology
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• v.31 no.5
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• pp.1178-1183
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• 1999

Essential oils were isolated from the peel of mandarin (Citrus unshiu Marc. Var. Okitsu) cultivated in Cheju Island. Among three different isolation methods investigated, simultaneous distillation gave higher yield 1.14%(w/w) than solvent extraction or cold pressing. The densities of essential oils were between 0.8409 and 0.8530, which showed no significant effect of the isolation methods. Some variations in the number of constituents detected and the content of d-limonene in the peel oils were observed depending upon the isolation methods. The citrus fruit was collected seasonally from the field and used as a sample for analysis. The peel thickness and the peel content of citrus fruit were around 2 mm and about 17% on wet weight basis, respectively, in harvest season. The maximum yield of essential oils was obtained in September from citrus peels just prior to ripeness and thereafter the yield had a tendency of decrease but remained over 1%(w/w). The relative content of d-limonene, the major constituent of citrus peel oils. increased gradually with ripening up to 68.69%(relative peak area, RPA). The other minor constituents were ${\gamma}-terpinene,\;{\beta}-elemene$, farnesene, hexadecanoic acid, ${\alpha}-pinene,\; {\beta}-myrcene$ and linalool in the decreasing order of their own contents of 7.75, 2.96, 2.29, 1.76, 1.63, 1.56 and 1.46%(RPA).

• Journal of Bio-Environment Control
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• v.11 no.2
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• pp.81-87
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• 2002

This study was conducted to investigate the cooling efficiency and growth of tomatoes by root zone cooling device using a pad-box and cultivated system. The structure of the root zone cooling system using a pad-box was four piece of pads bonded an the side and a fan set at the bottom. Cool wind was generated by the outside air which was punched at intervals of 10 cm along three rows. Cold wind flowed to the root zone in the culture medium. The root zone cooling efficiency of cold wind generation by using a pad-box flowing through a wet-pad was determined. Major characteristic of this cuttural system consist of bed filled with a perlite medium and a ventilation pipe using PVC. The cold wind generation by a pad box (CWP) was compared to that of cold wind generation by a radiator (CWR), cold water circulation using a XL-pipe (CWX) and the control (non-cooling). When the temperature of water supplied was 16.2-18.4$^{\circ}C$, temperatures in the medium were 20.5~23.2$^{\circ}C$ for CWP 22.7~24.2$^{\circ}C$ for CWR, 22.8~24.27$^{\circ}C$ for CWX and 23.1~-29.6$^{\circ}C$ for the control. The results show that the cold wind temperature using the pad-box was lower by 1~2$^{\circ}C$ than that of cold water circulation in the XL-pipe and lower by 5~6$^{\circ}C$ than that of the control. Growth such as leaf length, leaf width, fresh weight and dry weight, was greater in three root zone cooling methods than in the control. Root activity was higher in the rat zone cooling methods than in the control. However, there was no significant difference among root zone cooling methods.

• Korean Journal Plant Pathology
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• v.3 no.4
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• pp.252-260
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• 1987

Incidence of lettuce drop was observed throughout the growing season in the vinylhouse at the southern part of Korea, Kimhai. Occurrence of this disease was especially severe at the seedling stage. Number of sclerotia in surface soil $(30\times30\times5cm)$ was 22.0 at the seedling stage, and 5.3 at harvest in the infected area. Temperature for mycelial growth ranged from 5 to $30^{\circ}C$ with optimum temperature at $25^{\circ}C$. Sclerotia were formed fewer at low temperature, but their size was larger resulting in heavier dry weight than that at high temperature. The apothecia were formed from the sclerotia that were buried in March, April and September upto 3cm soil depth, but formed from those buried only 1 em soil depth in October. Sclerotia buried in June and December did not form apothecia regardless of soil depth by 90 days. The sclerotia buried in the 5cm of soil depth did not form apothecia. Sclerotia that were embedded in wet or flooded soil at $25^{\circ}C$ and $30^{\circ}C$ for 5 weeks lost their viability. Infection of lettuce was possible with mycelia originated from sclerotia on autoclaved lettuce plant fragments. The fungus was pathogenic on 25 plant species in 8 families in artificial inoculation tests. Lettuce seedlings appeared to be infected by airborne ascospore originated from sclerotia on crops and weeds around paddy fields, because sclerotia existing in soil might perish under long flood conditions during rice cultivation.

• Journal of the Korean Society of Food Science and Nutrition
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• v.34 no.10
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• pp.1611-1618
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• 2005

The microbiological examinations were conducted for the hygienic evaluation on three Korean restaurants during summer season in Busan, Korea. Total one hundred and sixty swabbed samples using sponge were collected from the surface of facilities and utensils at restaurants and total and coliform counts were measured. Also thirty- six air samples were collected at inside of three restaurants for measuring total, coliform, Staphy-lococcus and mold and yeast counts. All collected samples kept in an ice-packed box were transported to the laboratory and analyzed. The results demonstrated that most swabbed samples were highly contaminated with microorganisms and coliforms. The degree of contamination depended on the sampling sites. Averages of total counts of surface swab samples were ranged from not detectable to 2.14$\times\10^{9}$/200 $cm^{2}$, while those of coliforms from not detectable to 8.34$\times\10^{7}$/200 $cm^{2}$/200 $cm^{2}$. Microorganisms also detected from most agar strips of air samples for total, coliform, Staphylococcus and mold and yeast counts. The severely contaminated sites were floor, trench, water bottle, plastic drainer, rubber gloves, shelves, and unsealed wet towel. Those sites should be focused and controlled according to control Points of sanitation standard operating Procedures. Also, periodic microbiological examination in addition to visual examination should be applied on those highly contaminated sites for reducing risk of foodborne disease outbreak at restaurants

• Journal of the Korean Society for Marine Environment & Energy
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• v.12 no.2
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• pp.75-83
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• 2009

In order to understand the impacts of the construction of artificial sea dikes on carbon cycle in Samangeum area being a closed environment after April, 2006, we had measured suspended particulate matters, particulate and dissolved organic carbon in the surface water of inner Saemangeum dike from 2003 to 2006. The significant inputs of suspended particulate matter and organic carbon were mainly occurred during the wet season which suggests that most organic matter loading is concentrated within a short period of time inside the dike. The concentrations of particulate matter and organic carbon have gradually increasing every year inside of dike from the Mangyeong river estuary to Saemangeum dike, which has been closed since 2003 after the construction of the 4th dike. The particulate organic carbon increased due to the phytoplankton blooms by eutrophication. If the large portion of particulate organic matter produced in the surface water sink to the bottom sediment, this will cause the anoxic condition in this closed environment.

• Korean Journal of Environmental Agriculture
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• v.26 no.2
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• pp.116-123
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• 2007

This experiment was conducted to investigate the distribution and burden characteristics of heavy metals in the rainwater sampled at Suwon area, in the middle part of Korea, from April 2002 to October 2003. The relationship between concentration of heavy metal and other chemical properties in the rainwater was also evaluated. Chemical properties in the rainwater were various differences with raining periods and years. It appeared that a weighted average pH of rainwater was ranged from 4.7 to 5.5. Heavy metal concentrations in the rainwater were ranked as Zn>Pb>Cu>Ni>Cr>As>Cd. As compared with heavy metal concentrations of rainwater in 2002, Cd, Cu and As were higher than other element in 2003. There were positive correlation between major ionic components, such as Ca, Mg, and K, and heavy metal concentrations of rainwater, and As, CU, Cu, Zn and Ni were relatively higher relationship than Pb and Cr in respective to correlation coefficient. For heavy metal distribution of rainwater, the order of average enrichment factors was Cd>Pb>AS>Cu>Zn>Ni>Cr, and these were relatively higher than the natural component such as Fe, Mg and Ca. The monthly enrichment factors were relatively high in the spring (from April to May) at Suwon. The monthly amount of heavy metal precipitation was high in the rainy season from June to August because of great influence of rainfall.

• Journal of Korea Water Resources Association
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• v.48 no.10
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• pp.857-868
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• 2015

Hydraulic and water quality models with high reliability are necessary for the efficient management of water quality in the reservoir. The model capacity can be demonstrated by the application for the various hydrological conditions. CE-QUAL-W2 model is laterally averaged two-dimensional hydraulic and water quality model. The W2 model, which is suitable for the narrow reservoir like the Jinyang reservoir as compared with the depth and length of waterbody, has been frequently used by many researchers. Namgang watershed is expected to increase the water demand. In this study, the W2 model is validated under two different hydrological conditions; wet year (2011) and normal year (2009). Using hydrological and water quality condition for calibration, 2011, the effect of water intake increase was simulated. The simulation results showed that the increase of water intake led to increase the concentrations in total nitrogen, total phosphorus and Chlorophyll-${\alpha}$ concentration. Especially the concentration increase was appeared during the dry season in each of up to 62.53% (Total nitrogen), 39.07% (Total phosphorus) and 232.19% (Chlorophyll-${\alpha}$). The changes of chlorophyll-${\alpha}$ is similar to those of total phosphorus concentration.

• Journal of Environmental Science International
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• v.21 no.10
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• pp.1275-1286
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• 2012

Coastal marine ecosystem plays important role of spawning and nursery grounds for fisheries resources. Yongil Bay is one of major coastal marine ecosystems, which is located in the southwestern East Sea of Korea. Species composition and abundance of marine organism in the Yongil Bay were investigated by season from March to November 2009. Gill net and pot fisheries were used for survey of pelagic and demersal species composition, and collected 106 species, 67 families, and 7 taxa of fisheries resources from the coastal ecosystem. Species were included 2 species in Ascidiacea, 2 species in Bivalvia, 6 in Cephalopoda, 22 in Crustacea, 5 in Echinodermata, 12 in Gastropoda, and 57 in Pisces. Diversity indices (Shannon index, H') showed seasonal variation with low value of 2.11 in winter, and high value of 2.63 in autumn. Main dominant species were Asterias amurensis, Pleuronectes yokohamae, Siphonalia spadicea fuscolineata, Trachurus japonicas, Sillago japonica, Conger myriaster, Volutharpa ampullaceal, Engraulis japonicus, Asterina pectinifera, and Portunus (Portunus) sanguinolentus that were occupied over 71.5% of total individuals, and 52.9% of wet weight. Seasonal variations of fisheries resources composition were discussed on correlationships with those of environmental factors in the coastal ecosystem of the Yongil Bay in Korea. Those results from this study will provide scientific data and information to develop the ecosystem-based coastal fisheries assessment and management system in Korea.

• Journal of Korea Water Resources Association
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• v.53 no.11
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• pp.961-971
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• 2020

The Intergovernmental Panel on Climate Change (IPCC) reported that the amount of precipitation in South Korea would increase regardless of the reduction of Greenhouse Gas (GHG) emissions. Moreover, the temporal and spatial rainfall variation would also increase in the future. Due to the geographic allocation of Korea, more than 80% of the annual precipitation occurs in the wet season from early July to late September. It is expected that the average precipitation in this period will increase from the Representative Concentration Pathways (RCP) scenario projections. These predictions imply an increased variability of available water resources. Rainwater harvesting system is widely used as an alternative water resources today. This study introduces a RBSN (rain barrel sharing network) as an efficient way to utilize alternative water resources under the RCP scenarios. The concept of RBSN combines individual rainwater harvesting system to a sharing network, which make the whole system more reliable. This study evaluated a RBSN in South Korea composed of four users based on a storage-reliability-yield (SRY) relationship. The study area comprises all 17 provincal areas in South Korea. The result showed a huge benefit from a RBSN in Korea under the historical rainfall condition. Even in the climate change condition, the results showed that a RBSN is still beneficial but the changes in reliability are different depending on provinces in Korea. The results of this study shows that a RBSN is a very effective and alternative measure that can deal with the impacts of climate change in the near future.

• FLOWER RESEARCH JOURNAL
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• v.18 no.3
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• pp.216-219
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• 2010

An Asiatic lily cultivar 'Yeri' was developed in 2005 at National Institute of Horticultural and Herbal Science (NIHHS), Rural Development Administration (RDA), Korea. The cross was made in 1993 between Asiatic lily 'Geneve', a light pink colored cultivar, and 'Montreux', deep purple colored cultivar. The first selection was done and was tentatively named as 'A95-68' in 1995. After in vitro multiplication and bulbing production, growth and flowering characteristic tests were conducted from 1996 to 2003. The evaluation of characteristics was performed and named as 'Wongyo C1-19' in 2005 that was registered as 'Yeri' to the registration office of Korea Seed & Variety Service. 'Yeri' flowered at the first of July and grew average 34.6 cm stem in length. Flowers bloomed facing upward, unspotted in petals and deep purple (RHS, RP58A). The size of flower was 13.3 cm. Mean petal length and width was 7.7 cm and 2.7 cm, respectively. Leaves were 5.1 cm long and 0.5 cm wide, respectively. The weight and size of bulb were 9.6 g and 11.7 cm, respectively. Year-round flowering can be done by storing the bulb under $-1.5^{\circ}C$ conditions. For forced cultivation, it was necessary to add calcium to the fertilizer or remove side scales to prevent leaf scorch. It was needed to control Botrytis disease in wet season.