• Journal of Plant Biotechnology
• /
• v.37 no.1
• /
• pp.25-46
• /
• 2010

The demand for fuel and energy resources continues to grow due to increased consumption and emerging economies in all parts of the world. With this increase in demand, crude oil prices in the international market has jumped dramatically. Global warming, which is a consequence of increasing greenhouse gas (GHG) emissions, has become scientific, social, and political concerns. To cope with global warming and energy crisis, cost-competitive biofuels are urgently needed. In addition, development of an infrastructure, which supplies energy stably and diversifies energy resources, as well as new cost-saving technologies should be developed to reduce the costs of producing biofuels. Due to high oleic acid content, rapeseed (Brassica napus L.) is currently the potential feedstock for biodiesel production in temperate zone region and the production and use of rapeseed oil is already commercialized in Europe. In Korea double-cropping (rice and rapeseed) became more prevalent because it reduces competitions from land constraints. Production of rapeseed as a biodiesel feedstock may reduce the influence of rising oil prices and nation's dependence on imported petroleum and increase job opportunities and farm incomes.

• Korean Journal of Ecology and Environment
• /
• v.43 no.4
• /
• pp.492-502
• /
• 2010

The study objects were to analyze long-term and seasonal variations of nutrients (N, P), suspended solids, N:P ratios, algal chlorophyll, and trophic state along with general water quality parameters in four sampling sites including two intake tower sites supplying drinking water in Daechung Reservoir. For the analysis, we used water quality long-term data sampled during 1998~2007 by the Ministry of Environment, Korea. Interannual and seasonal trends in inflow and discharge near the intake tower facilities over the ten years were directly influenced by rainfall pattern. The distinct difference between wet year (2003) and dry year (2001) produced marked differences in water temperature, pH, dissolved oxygen, organic matter contents, nutrients, and these variables influenced algal biomass and trophic state. Values of TP varied depending on the year and locations sampled, but monthly mean TP always peaked during July~August when river inflow and precipitation were maxima. In contrast, TN varied little compared to TP, indicating lower influence by seasonal flow compared to phosphorus. The number of E. coli were highest in Site 2 (Chudong intake tower) and varied largely, whereas at other sites, the numbers were low and low variations. Contents of chlorophyll-${\alpha}$ (CHL), as an estimation of primary productivity, varied largely depending on the year and season. The maximum of CHL occurred at Muneu intake tower (S4) during 2006 when the precipitation and inflow were lowest. In contrast, another CHL peak was observed in Site 2 (Chudong intake tower) in 2006 when one of the largest typoons (Ewinia) occurred and river runoff were maximum. So the CHL maxima were associated with both wet year (high flow, high nutrient supply) and dry year (low flow, nutrient supply by littoral zone). Such conditions influenced trophic states, based on Trophic State Index of nutrients and CHL. Based on all analyses, we can provide some clues for management and protection strategies of two intake tower sites.

• The Journal of the Korea Contents Association
• /
• v.11 no.5
• /
• pp.403-412
• /
• 2011

This study aims at proposing clear direction of tourism policy through analyzing the correlation between tourism resource, tourism system and activation of regional economic. A total of 283 samples were ultimately collected in survey of 300 researchers from the national and public institutes in provinces Chungchong-do and Kyungsang-do in July 2010 alone. SPSS 15.0 and AMOS 6.0 were used to test the model. Analysis showed that the more regional tourism resources have more significant effect on tourism system and tourist-attracting strategy, and that tourism system exerts influence on tourist-attracting strategy. So it was proved that the tourism policy effects meaningfully on vitalization of regional economic, and it was confirmed that the tourism system is more effective on the energization of regional economic than the tourist-attracting strategy. But the hypothesis has been rejected unexpectedly that tourist attractions have consequences for the activation of regional economic. It establishes the fact that it is useless for regional economy regardless of abundant regional tourism resources, if the tourism policy is not concretely in force. Therefore, Korean government must intercept overissue and overlapping investments on tourism development by the local government and induce qualitative growth of tourism sector through upgrading of development guidelines and the criteria for selecting tourism special zone, regional festival and cultural assets, and its continuous assessment and management. And it is desirable to enforce the connected cooperation projects between local governments and the 5+2 great-sphere economic blocs on government-level.

• Journal of Ginseng Research
• /
• v.38 no.1
• /
• pp.1-7
• /
• 2014

Background: Although ginsenosides such as Rg1, Rb1 and Rg3 have shown promise as potential nutraceuticals for cognitive impairment, their use has been limited due to high production cost and low potency. In particular, the process of extracting pure Rg3 from ginseng is laborious and expensive. Methods: We described the methods in preparing ginseol k-g3, an Rg3-enriched fraction, and evaluated its effects on scopolamine-induced memory impairment in mice. Results: Ginseol k-g3 (25-200 mg/kg) significantly reversed scopolamine-induced cognitive impairment in the passive avoidance, but not in Y-maze testing. Ginseol k-g3 (50 and 200 mg/kg) improved escape latency in training trials and increased swimming times within the target zone of the Morris water maze. The effect of ginseol k-g3 on the water maze task was more potent than that of Rg3 or Red ginseng. Acute or subchronic (6 d) treatment of ginseol k-g3 did not alter normal locomotor activity of mice in an open field. Ginseol k-g3 did not inhibit acetylcholinesterase activity, unlike donezepil, an acetylcholinesterase inhibitor. Rg3 enrichment through the ginseol k-g3 fraction enhanced the efficacy of Rg3 in scopolamine-induced memory impairment in mice as demonstrated in the Morris water maze task. Conclusion: The effects of ginseol k-g3 in ameliorating scopolamine-induced memory impairment in the passive avoidance and Morris water maze tests indicate its specific influence on reference or long-term memory. The mechanism underlying the reversal of scopolamine-induced amnesia by ginseol k-g3 is not yet known, but is not related to anticholinesterase-like activity.

• Korean Journal of Materials Research
• /
• v.21 no.10
• /
• pp.573-579
• /
• 2011

Highly textured Ag, Al and Al:Si back reflectors for flexible n-i-p silicon thin-film solar cells were prepared on 100-${\mu}m$-thick stainless steel substrates by DC magnetron sputtering and the influence of their surface textures on the light-scattering properties were investigated. The surface texture of the metal back reflectors was influenced by the increased grain size and by the bimodal distribution that arose due to the abnormal grain growth at elevated deposition temperatures. This can be explained by the structure zone model (SZM). With an increase in the deposition temperatures from room temperature to $500^{\circ}C$, the surface roughness of the Al:Si films increased from 11 nm to 95 nm, whereas that of the pure Ag films increased from 6 nm to 47 nm at the same deposition temperature. Although Al:Si back reflectors with larger surface feature dimensions than pure Ag can be fabricated at lower deposition temperatures due to the lower melting point and the Si impurity drag effect, they show poor total and diffuse reflectance, resulting from the low reflectivity and reflection loss on the textured surface. For a further improvement of the light-trapping efficiency in solar cells, a new type of back reflector consisting of Ag/Al:Si bilayer is suggested. The surface morphology and reflectance of this reflector are closely dependent on the Al:Si bottom layer and the Ag top layer. The relationship between the surface topography and the light-scattering properties of the bilayer back reflectors is also reported in this paper.

• Journal of the Korean association of regional geographers
• /
• v.7 no.1
• /
• pp.1-20
• /
• 2001

This study explored the changes of the patterns of land use and the social patterns of ownership of Kumnamno in Kwangju under the rule of Japanese colonialism by analyzing the townscape of Kumnamno in terms of the form and function of it. The research was done considering three periods: the year of 1912, 1930 and 1945. Kumnamno is the name of the street as well as the legal district name, and includes Kumnamno 1-ga, 2-ga, 3-ga, 4-ga and 5-ga. In the year 1912, Kumnamno was utilized as land, farmland and road. With the increase in population and the urbanization of the Kwangju area, it gradually began to be changed into land. By 1941, it was completely turned into land. Before and after the year 1910, the streets intersecting the Kumnamno area came into being as the roads of the Kwangju town, and were built with a lattice pattern. The road building of the Kumnamno began in accordance with the building of Kwangju station in 1922. The road building linking Kwangju Station to Chonnam Provincial Hall marked the first appearance of Kumnamno. The block from Ku-sung-no to Kumnamno 3-ga was built in 1925, the block from Kumnamno 3-ga to 2-ga in 1921, and Kumnamno 1-ga in 1930. It was not until the year 1933 that the construction of streets ranging from Ku-sung-no through Kumnamno 5-ga was finished. Examining the land ownership of the Kumnamno area in 1912, the Japanese possessed the land of Kumnamno 1-ga, 2-ga and 3-ga on the one hand and the Koreans possessed the land of 4-ga and 5-ga on the other hand. In 1930, the Japanese enlarged their sphere of influence and controlled the land located in all the areas of Kumnamno, and the Koreans reduced their ownership of Kumnamno 4-ga and 5-ga. There was a tendency for companies to occupy the land rapidly. In 1945, while the land owned by the Japanese decreased and the land owned by the Koreans did not change in quantity, the possessions of companies increased. To summarize, the Kumnamno area had some changes in the use of land during the above mentioned period. This was in part due to the construction of a street linking Kwangju Station to Chonnam Provincial Hall in order to strengthen the authority of the Japanese Government-General of Korea, as well as the expansion of the residential zone with the increase of the population of Kwangju.

• Journal of Korean Society of Environmental Engineers
• /
• v.34 no.6
• /
• pp.421-429
• /
• 2012

This study was aimed to analyze the water quality characteristics of the Hwapocheon Stream and to be utilized in the further related research. Water in the upper stream became a dammed pool due to the existence of 14 weirs, and pollutants such as both sewage and irrigation water were introduced into the mainstream passing through farming settlements and agricultural land. For these reasons, filamentous cyanobacteria (Oscillatoria sp.) bloomed at the bottom of the dammed pool. Also in the midstream and downstream, tributaries with high pollutant concentrations [e.g., Comocheon (T3) and Yongdeokcheon (T8)] were inflowed, and had a negative impact on water quality of the mainstream, especially nitrogen and phosphorus. In the Hwapocheon Stream, dissolved oxygen (DO) decreased, and suspended solid (SS) increased toward the downstream. The result showed that hydraulic retention time, SS, COD, and concentration of $NH_4{^+}$ were important water quality factors of the Hwapocheon Stream. The high concentration of benthic organic matter and rich in attached algae in the core of Hwapo-wetland were expected to give impact on the water quality of the mainstream. In the spatial manner, water quality showed increasing trend in the weir zone, and it was constant or decreased trend in wetland. In the seasonal manner, the nutrient concentrations were high in the winter dry season, however, the organic matter concentrations were high in spring and summer. Generally, the concentrations of phytoplankton value were $40{\mu}g\;chl-{\alpha}/L$ or less in all reaches except for the high concentrations in the weir and wetland area in June.

• Geophysics and Geophysical Exploration
• /
• v.5 no.1
• /
• pp.56-63
• /
• 2002

Tracing the history of study, problems of seawater intrusion are commonly investigated with electrical techniques because seawater saturated zone is indicative of the low resistivity anomaly. There we, however, silt and mud layers in the western and southern coastal areas of Korea, so we may make a mistake in case we determine seawater intrusion only with resistivity survey. Hence, reference IP survey was carried out in Kimje, Jeollabuk-Do and Youngkwang, Jeollanam-Do in order to decide whether or not the area is under the influence of seawater intrusion. With the use of a electric field cable to minimize EM coupling, we obtained more accurate results by appling reference If technique measuring simultaneously wavelet of current as well as potential. With the aid of reference IP technique, it is possible that we can exactly evaluate seawater intrusion by discriminating seawater saturated area (no IP effect) from very highly conductive layer composed of clay mineral (high IP effect).

• Geophysics and Geophysical Exploration
• /
• v.9 no.4
• /
• pp.291-298
• /
• 2006

Resistivity method is a practical and effective geophysical technique to detect leakage zones in embankment dams. Generally, resistivity survey conducted along the crest assumes that the embankment dam has a 2D structure. However, the 3D topography of embankments distorts significantly resistivity data measured on anywhere of the dam. In this study, we analyse the influence from 3D effects created by specific dam geometry through the 3D finite element modeling technique. We compared 3D effects when resistivity surveys are carried out on the upstream slope, left edge of the crest, center of the crest, right edge of the crest and downstream slope. We ensure that 3D effect is greatly different according to the location of the survey line and data obtained on the downstream slope are most greatly influenced by 3D dam geometry. Also, resistivity data are more influenced by the electrical resistivity of materials constituting reservoir than 3D effects due to specific dam geometry. Furthermore, using resistivity data synthesized with 3D modeling program for an embankment dam model with leakage zone, we analyse the possibility of leakages detection from 2D resistivity surveys performed along the embankment dam.

• Korean Journal of Environment and Ecology
• /
• v.32 no.1
• /
• pp.77-96
• /
• 2018

We investigated and analyzed three Korean island sites (Bijin-do, Ae-do, and Bogil-do) and one Japanese site (Tachibanayama) of sword-leaf litsea (Actinodaphne lancifolia) forests, known as the climax forest, to discuss the vegetation succession sere of warm-temperature evergreen broad-leaved forests. We then reviewed the literature in Korea, Japan, China, and Taiwan to consider the distribution characteristics of evergreen broad-leaved forests, vegetation succession sere, and climax tree species. Although Mt. Tachibana and Ae-do showed the most advanced vegetation structure, the soil and ordination (CCA) analysis indicated that it was not enough to consider that the sword-leaf litsea forest was at the climax stage in the warm-temperature region. The Actinodaphne lancifolia forest is sparsely distributed in Korea and Japan while the common types of vegetation in the warm temperate zone region in East Asia are Machilus spp., Castanopsis spp., and Cyclobalanopsis spp. The vegetation succession sere of the Korean warm-temperature region is thought to have a secondary succession such as Pinus thunbergii, P. densiflora, Q. serrata (early stage) through Machilus thunbergii, innamomum yabunikkei, Neolitsea sericea, Actinodaphne lancifolia (middle stage) to Castanopsis sieboldii, Q. acuta, Q. salicina (climax stage). However, Machilus thunbergii will be the climax species as an edaphic climax in places where there is a strong influence of the sea wind, or it is difficult to supply the seeds of Castanopsis spp. and Cyclobalanopsis spp.