• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.30 no.3
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• pp.295-303
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• 2012

Clarify wind energy productivity depends on three factors: the wind probability density function(PDF), the turbine's power curve, and the air density. The wind PDF gives the probability that a variable will take on the wind speed value. Wind shear refers to the change in wind speed with height above ground. The wind speed tends to increase with the height above ground. also, Wind PDF refers to the change with height above ground. Wind analysts typically use the Weibull distribution to characterize the breadth of the distribution of wind speeds. The Weibull distribution has the two-parameter: the scale factor c and the shape factor k. We can use a linear least squares algorithm(or Ln-least method) and moment method to fit a Weibull distribution to measured wind speed data which data was located same site and different height. In this study, find that the scale factor is related to the average wind speed than the shape factor. and also different types of terrain are characterized by different the scale factor slop with height above ground. The gross turbine power output (before accounting for losses) was caculated the power curve whose corresponding air density is closest to the air density. and air desity was choose two way. one is the pressure of the International Standard Atmosphere up to an elevation, the other is the measured air pressure and temperature to calculate the air density. and then each power output was compared.

• Journal of The Korean Society of Grassland and Forage Science
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• v.22 no.1
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• pp.23-30
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• 2002

Eveuadies 71' kenaf (Hibiscus cannabinus L.) was grown at five plant densities (1, 2, 3, 4, and 5 plants per hill; 16,000, 32,000, 48,000, 64,000 and 80,000 plants/10a) from April 13 to October 8, 2001 in Jeju island to determine influence of plant number per hill on agronomic characteristics, forage yield and quality. As plant density increased from 1 to 5 plants per hill, the plant height averaged across two harvests increased 176 to 185 cm. Compared with the plant density of two plants per hill, the plant height decreased at higher plant densities (183, 180, and 166 cm for 3, 4 and 5 plants per hill). The highest yield of fresh forage (114.6 MT/ha), dry matter (17.3 MT/ha), crude protein (2.33 MT/ha), and total digestible nutrients (TDN) (9.21 MT/ha) was obtained at 2 plants per hill. As plant density increased from 1 to 5 plants per hill, crude protein, ether extract, nitrogen free extract, and TDN contents increased from 13.1 to 15.4%, 3.0 to 3.7%, 20.1 to 23.2% and 41.1 to 45.4%, respectively, while crude fiber and crude ash contents decreased from 41.2 to 34.9% and 9.4 to 8.2%, respectively.

• Journal of the Korean Society of Marine Environment & Safety
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• v.17 no.2
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• pp.123-129
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• 2011

A study on the occurrence and movement of marine debris is required for protecting the marine environment and ecosystem from marine pollution. The aim of this study is to show annual production and movement characteristics through analysis for the flow path, composition and the sources of marine debris. This study analyzed the distribution and characteristics of marine debris collected in the region of $100\;m{\times}20\;m$($=2,000\;m^2$) at the Daekwang Beach in the Yellow Sea. During the collection period from 2008 to 2010, the total weight of the marine debris was 1,445 kg in this site. The most marine debris was plastic amounting to 46.5% of the whole collection; the rest were styrofoam(20%) and wooden material(12.6%). The amount of marine debris mused from foreign country observed 155.5 kg, more than 90% of them was plastic came from China such as buoys. Additionally, this study analyzed seasonal change if marine environment to understand occurrence amount change if marine debris. 2009 and 2010 was high occurrence ratio in season that the north wind is very strong and the occurrence rate appeared highest by 40% in the summer(July) of 2008 that appeared westbound tidal current. Overall, marine Debris mused from foreign country was high occurrence ratio in January, May and then November has a lot of quantity secondly. While, occurrence ratio was the highest by 46% summer(July) in 2008, but in 2009 and 2010 showed the lowest rate to 4%.

• Journal of Korean Society of Forest Science
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• v.99 no.3
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• pp.312-322
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• 2010

In Korea, Torreya nucifera (L.) Siebold & Zuccarini is widely distributed in the warm temperate zone of South coastal area and Jeju island, mainly as preserved forest in the vicinity of the Buddhist temple and Confucian temple. The objective of this study is in order to develop the conservation method and comprehension of vegetation community by current vegetation structure analysis of Torreya nucifera stand. As the results, the number of surveyed species in Torreya nucifera stand were total 148 species with 28 species of tree layer, 38 species of subtree layer, and 82 species of shrub layer. The appearance of the common species were Ligustrum obtusifolium Siebold & Zucc., Hedera rhombea Bean, and Trachelospermum asiaticum Nakai var. asiaticum. All the story of the surveyed region, Torreya nucifera maintained the current dominant species, but the subtree layer and shrub layer was decreased dominant rate because of the development of the crown of tree layer and biased growth of the subtree layer. Most of the tree layer and subtree layer in Torreya nucifera stands are composed of the sprout forest. Therefore, these results suggest that in order to maintain the healthy stand it is demanded for the application of selection thinning method for reducing crown competition in Torreya nucifera forests.

• Korean Journal of Plant Taxonomy
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• v.41 no.4
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• pp.429-439
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• 2011

We investigated the flora of Imja-do(Isl.), an island of the Shinan archipelago, located in Imja-myeon, Shinan-gun, Jollanamo-do and discussed the vascular plants found there. Twenty-four separate field trips (100days) were completed from August of 1997 to October of 2009. As a result, we identified the distribution of 526 taxa in Imja-do(Isl.), comprising 112 families, 331 genera, 463 species, 1 subspecies, 60 varieties, and 2 forms. There are a total of 78 taxa of floristic regional indicator plants and one taxon of level II endangered species, Millettia japonica, as designated by the Korean Ministry of the Environment. The floristic regional indicator plants are as follows; four taxa of level V such as Utricularia bifida, two taxa of level IV such as Cladium chinense, 14 taxa of level III such as Aletris spicata, three taxa of level II, and 55 taxa of level I. In addition, one endangered species (EN), Nymphoides coreana, five vulnerable species (VU),such as Ilex cornuta, and three near-threatened species (NT) such as Utricula riaracemosa, were found in the investigated area. The plants of Imja-do(Isl.) are classified into four types based on the plant geographical origin, as follows: 1) boreal plants advancing southward in a glacial period, 2) temperate plants spreading eastward from the Himalayas and China to Japan passing through the south coast of Korea, 3) subtropical plants, and 4) indigenously developed endemic species of the warm-temperate region of East Asia.

• Korean Chemical Engineering Research
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• v.46 no.5
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• pp.958-964
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• 2008

In this work, micro-sized dextran particles, which have recently been focused as one of the candidate materials for the Drug Delivery System(DDS), were prepared by means of the Supercritical Antisolvent (SAS) process with $CO_2$. With dimethyl sulfoxide(DMSO) as the solvent, effects of the operating variables such as temperature (308.15~323.15 K), pressure(90~130 bar), solute concentration(10~20 mg/ml), and the molecular weight of the solute(Mw=37,500, 450,000) on the size and morphology of the resulting particles were thoroughly observed. The higher solute concentration led to the larger particles, however, the injection velocity of the solution and pressure did not show significant effects on the resulting particle size. With dextran of the lower molecular weight, the smallest particles were obtained at 313.15 K. On the other hand, the size of the particles from the high molecular weight dextran ranged between $0.1{\sim}0.5{\mu}m$ with an incremental effect of the temperature and pressure. For the solute concentration of 5 mg/ml, the lower molecular weight dextran did not form discrete particles while aggregation of the particles appeared when the solute concentration exceeded 15 mg/ml for the higher molecular weight dextran. It is believed that if the solute concentration is too low, the degree of the supersaturation in the recrystallization chamber would not be sufficient for initiation of the nucleation and growth mechanism. Instead, the spinodal decomposition mechanism leads to formation of the island-like phase separation which appears similar to aggregation of the discrete particles. This effect would be more pronounced for the smaller molecular weight polymer system due to the narrower phase-splitting region.

• The Journal of Engineering Geology
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• v.16 no.2 s.48
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• pp.125-134
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• 2006

In order to establish the in-situ application of the artificial storage and recovery (ASR) technology which is used the property of the aquifer storage of groundwater. We carried out to the in-situ experiments such as borehole TV logging, pumping test and artificial hydraulic fracturing in volcanic island, Ulleungdo. In-situ experiments were conducted to divide the before- and after-hydraulic fracturing. Pumping test was achieved to confirm the two fracture zones, GL-13m and GL-21m, which are determined by the borehole TV logging. From the results of the before- and after-pumping tests, the hydraulic connectivity was confirmed to locate at GL-13m in the residual deposit zone of pumice media as alluvium. However, in the bedrock tone at GL-21m the hydraulic connectivity could be considered to faulty. Consequently, in this study area the artificial recharge has a little unsatisfied to geo-structural condition and desired to more detail investigation works.

• Korean Journal of Environmental Biology
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• v.31 no.4
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• pp.288-294
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• 2013

Recently, sustainable production of biofuel using algal biomass is being pursued because of its enormous potential. First and foremost, securing superior strains to develop an efficient production system for algal biodiesel through screening or genetic improvement of microalgae is necessary. The genus of Botryococcus is regarded as one of the superior microalgae for biodiesel production due to its ability to accumulate high amounts of lipids and hydrocarbons. However, its low growth rate is a bottleneck for large-scale production and commercialization. The purpose of this study is to obtain indigenous Botryococcus strains which possess high lipid content and biomass productivity. The Botryococcus sp. was isolated from the Seobu Reservoir in Jeju Island and identified as Botryococcus sudeticus J2 by comparative analysis of 18s rRNA gene and ITS regions. The biomass productivity and lipid content of B. sudeticus J2 were 0.116 g $L^{-1}day^{-1}$ and 40.1% of dry wt., respectively. This was higher than the value of B. braunii UTEX 572, which is widely regarded as a superior strain among Botryococcus species. The relatively high growth rate of B. sudeticus J2 was achieved under a light intensity of 240 ${\mu}mol$ photons $m^{-2}s^{-1}$ with ambient air spargingwhen compared to 120 ${\mu}mol$ photons $m^{-2}s^{-1}$ with 2% $CO_2$ supply. In summary, it is likely that the isolated B. sudeticus J2 can be used for the mass cultivation and biodiesel production.

• Analytical Science and Technology
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• v.24 no.1
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• pp.38-44
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• 2011

The quality of decoction water would be important for the preparation of herbal medicines. Four types of decoction water, S1, S2, S3 and S4, three types of mineral water from Jeju island and one type of tap water from Seoul region were evaluated. The contents of minerals in decoction water were analysed by ICP-AES and ICP-MS. There was significant difference in the mineral contents between the types of decoction water. The bioactive components from rhubarb were extracted with four types of water and the relationship between mineral contents in water and the extracted amounts of components was evaluated. The total extraction was calculated by evaporating water and weighing the residue. The bioactive components in rhubarb were determined by HPLC method. Kruskall-Wallis rank sum tests were used. Multiple factor analysis was used to analyze the relation between the contents of mineral and total extraction or bioactive components in the decocted solutions. Not only the total extraction but also the amount of extracted bioactive components showed statistically significant relationship with the contents of minerals and anions in decoction water.

• Journal of the Korean Geographical Society
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• v.41 no.4 s.115
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• pp.435-456
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• 2006

This study examines the long-term spatial patterns and recent trends of seasonal onsets and durations defined by daily temperatures in South Korea for the period 1973-2004. Spatially, spring and winter onset dates show approximately 44 day and 63 day maximum difference respectively between south and north (Seongsanpo to Daegwallryeong) attributable to the impacts of latitudes and altitudes. In contrast, summer onset, which is more affected by proximity to oceans and altitudes than by latitudes, begins earlier in interior low elevated areas than in the coastal areas but earliest at higher latitudes than Jeiu Island. Five climatic types regarding the seasonal cycles in South Korea are spatially clustered according to the combination of longer seasonal durations. As a reflection of recent climate changes on seasonal cycles in South Korea, winter duration was shortened by 10 days during the post-1988 period due to a late winter onset of 4 days and an early spring onset of 6 days. The winter reduction began in the southern regions of the Korean Peninsula in the mid-1980s and spread northward during the 1990s period, ultimately appearing everywhere. In urbanized cities, where much of the surface is covered with asphalt or concrete, the winter reduction was intensified and summer duration was locally incremented. The reduced winter duration in recent decades shows significant teleconnections with variations of geopotential height (925hPa) in the eastern Arctic region ($0-90^{\circ}E$, $65-85^{\circ}N$) during the cold season. The reduction in winter duration in South Korea agrees with results in overall global warming trends as a climate change signal.