• Journal of Ecology and Environment
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• v.32 no.3
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• pp.167-176
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• 2009

Land cover changes associated with urbanization have driven climate change and pollution, which alter properties of ecosystems at local, regional, and continental scales. Thus, the relationships among urban ecological variables such as community composition, structure, health, soil and functioning need to be better understood to restore and improve urban ecosystems. In this study, we discuss urban ecosystem management and research from a futuristic perspective based on analyses of vegetation structure, composition, and successional trends, as well as the chemical properties of soils and the distribution of heat along an urban-rural gradient. Urban thermo-profile analysis using satellite images showed an obvious mitigating effect of vegetation on the Seoul heat island. Community attributes of Quercus mongolica stands reflected the effects of urbanization, such as pronounced increases in disturbance-related and pollution-tolerant species, such as Styrax japonica and Sorbus alnifolia. Retrogressive successional trends were detected in urban sites relative to those in rural sites. Changes in the urban climate and biotic environment have the potential to significantly influence the practice and outcomes of ecological management, restoration and forecasting because of the associated changes in future bio-physical settings. Thus, for management (i.e., creation and restoration) of urban green spaces, forward-thinking perspectives supported by historical information are necessary.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.12 no.6
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• pp.931-939
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• 2001

The slot coupling characteristics was analysed in a radial-line slot antenna for its design. The previously proposed waveguide model with a periodic boundary condition on its narrow walls and periodically arranged slots on its wide wall was used. The magnetic field integral equation and two dyadic Green\`s functions for respective regions was derived and the method of moments was used. To maximize the efficiency of numerical analysis and to extract singularities, two different kinds of basis functions, the entire domain basis function and the sub-domain one, are used. In addition, the Ewald sum technique for the rectangular waveguide and the Shanks transform for the half space were used to accelerate the computation of the slowly convergent potential Green\`s functions. Simulation results expressed the effects of the various design parameters on the slot coupling.

• Bulletin of the Society of Naval Architects of Korea
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• v.27 no.4
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• pp.15-26
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• 1990

This paper describes a potential-baoed panel method formulated for the analysis cf a supercavitating two-dimensional symmetri strut. The method employs normal dipoles and sources distributed on the foil and cavity surfaces to represent the potential flow around the cavitating hydrofoil. The kinematic boundary condition on the wetted portion of the foil surface is satisfied by requiring that the total potential vanish in the fictitious inner flow region of the foil, and the dynamic boundary condition on the cavity surface is satisfied by requiring that the potential vary linearly, i.e., the tangential velocity be constant. Green's theorem then results in a potential-based integral equation rather than the usual velocity-based formulation of Hess & Smith type, With the singularities distributed on the exact hydrofoil surface, the pressure distributions are predicted with improved accuracy compared to those of the linearized lifting surface theory, especially near the leading edge. The theory then predicts the cavity shape and cavitation number for an assumed cavity length. To improve the accuracy, the sources and dipoles on the cavity surface are moved to the newly computed cavity surface, where the boundary conditions are satisfied again. This iteration process is repeated until the results are converged.

• Journal of Climate Change Research
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• v.4 no.3
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• pp.211-219
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• 2013

This study uses the LEAP model that is a long-term energy analysis model to analyze reduction potential on S city residential sector energy usage for greenhouse gas emission. Energy consumption of S-si in 2009 is consumed most in residential and commerce sector by 39.1%. Also, energy and greenhouse gas emission of residential sector is expected to increase due to increase of households. Therefore, greenhouse gas reduction measures are desperately required in residential sector. For this study recognizes energy consumption of S-si residential sector and has established reduction measure of S-si residential sector greenhouse gas through literature search on domestic and foreign climate change correspondence policies. Also, construction of greenhouse gas reduction potential by reduction measures through LEAP model. There were a total of 5 reduction measures scenarios is Reference Scenario, LED Lighting, Energy Alternative, Green Life Practice, and Total Reduction Measure. As a result, greenhouse gas emission of Light Emitting Diode Lightings by 2020 was $1,181.0thousand\;tonCO_2eq$, decrease of 6.1% compared to the Reference Scenario and Greenhouse gas emission of Energy Alternative by 2020 was $1,171.6thousand\;tonCO_2eq$, decrease of 6.8% compared to the Reference Scenario. Greenhouse gas emission of Green Life Practice by 2020 was $1,128.7thousand\;tonCO_2eq$, decrease of 10.2% compared to the Reference Scenario. For Total Reduction Measures by 2020 emission was $966.9thousand\;tonCO_2eq$, decrease 23.1% compared to Reference Scenario.

• Journal of the Society of Naval Architects of Korea
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• v.30 no.2
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• pp.86-97
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• 1993

A numerical method is developed for the nonlinear motion of two-dimensional wedges and axisymmetric-forced-heaving motion using Semi-Largrangian scheme under assumption of potential flows. In two-dimensional-problem Cauchy's integral theorem is applied to calculate the complex potential and its time derivative along boundary. In three-dimensional-problem Rankine ring sources are used in a Green's theorem boundary integral formulation to salve the field equation. The solution is stepped forward numerically in time by integrating the exact kinematic and dynamic free-surface boundary condition. Numerical computations are made for the entry of a wedge with a constant velocity and for the forced harmonic heaving motion from rest. The problem of the entry of wedge compared with the calculated results of Champan[4] and Kim[11]. By Fourier transform of forces in time domain, added mass coefficient, damping coefficient, second harmonic forces are obtained and compared with Yamashita's experiment[5].

• Korean Journal of Materials Research
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• v.16 no.12
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• pp.761-765
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• 2006

[ $II-III_2-(S,Se)_4$ ] structured of phosphor has been used at various field because those have high luminescent efficiency and broad emission band. Among these phosphors, the europium doped $BaGa_2S_4$ was prepared by solid-state method and had high potential application due to an emissive property of UV region. Also, the common sulfide phosphors were synthesized by using injurious $H_2S\;or\;CS_2$ gas. However, in this study $BaGa_2S_4:Eu^{2+}$ phosphor in addition to excess sulfur was prepared under at 5% $H_2/95%\;N_2$ reduction atmosphere. Thus, this process could be considered as large scale synthesis because of non-harmfulness and simplification. The photoluminescence efficiency of the prepared $BaGa_2S_4:Eu^{2+}$ phosphor increased 20% than that of commercial $SrGa_2S_4:Eu^{2+}$ phosphor. The prepared $BaGa_2S_4:Eu^{2+}$ could be applied to green phosphor for white LED of three wavelengths.

• The Korean Journal of Mycology
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• v.46 no.2
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• pp.145-160
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• 2018

Members of Chlorociboria are soft-rot ascomycetes that produce blue-green pigment. We investigated the growth characteristics of two Korean species of Chlorociboria, eight strains of Chlorociboria aeruginascens and Chlorociboria poutoensis, under various culture conditions (solid media, temperature, pH) and screened them for extracellular enzyme activity. Although the growth rate was slow, all tested strains of Chlorociboria spp. grew well on potato dextrose agar (PDA; 16.3~42.6 mm after 60 days) or Sabouraud dextrose agar (SDA), but not on malt extract agar (MEA). Compared with C. aeruginascens strains, C. poutoensis strains exhibited higher expression of blue-green pigments on both PDA and SDA media. The optimal temperature for mycelial growth was $20{\sim}25^{\circ}C$, and mycelial growth was lower at $30^{\circ}C$ than at $10^{\circ}C$. All strains tended to have increased mycelial growth as the incubation temperature increased in the range of 10 to $20^{\circ}C$. The optimal pH of potato dextrose broth (PDB) for mycelial growth varied according to the strain under static culture conditions. Maximum biomass production was obtained at pH 6.0 for NIFoS 579 ($114.3{\pm}5.1mg/60days$), but it maintained a stable pigment expression under a broad pH spectrum. The activities of both cellulase and laccase were observed in all tested strains of Chlorociboria spp. Enzyme activities of NIFoS 579 were remarkably higher than those of the other strains. From these results, we suggest that C. poutoensis NIFoS 579 is a potential candidate for use as a source of natural blue-green dye.

• International Commerce and Information Review
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• v.11 no.2
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• pp.303-328
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• 2009

MERCOSUR, which is the biggest economic community in the Latin America, has great potential as Korea's export market with 220 million population and 2.8 trillion$ GDP. In the midst of global economic crises, the importance of MERCOSUR is highlighted with relatively sound economic growth. The average tariff rate of MERCOSUR is 10.4~12.2% which is almost same as that of Korea(12.2%), but the tariff rates on Korea's main export items such as auto, display, digital camera, mobile phone are as high as 20~30%, which means that Korea-MERCOSUR FTA will result in substantial growth of Korea's export. In pursuing Korea-MERCOSUR FTA, cooperations in natural resources, agriculture, mid-sized aircraft, construction and green energy as well as liberalization of commodity market are very important for Korea. To realize Korea-MERCOSUR FTA, it is essential to overcome the objections from the manufacturing sectors of MERCOSUR. So it is desirable to aim relatively low in terms of the level of liberalization at the beginning, and expand corporate and industrial cooperation between Korea and MERCOSUR's manufacturing industries.

• Korean Journal of Microbiology
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• v.46 no.3
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• pp.296-302
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• 2010

Microcystis (Cyanobacteria, Chroococcales) is one of the green tide-causing organisms in freshwaters, and some species produce microcystin that is hepatotoxin. In the aspects of freshwater quality controls and health concerns, therefore it is necessary to manage the harmful organisms. In the present study, RNA polymerase beta subunit (rpoB) gene sequences of Microcystis were determined and characterized in order to use a potential marker for the molecular detections of the species. Microcystis rpoB showed high divergences of DNA similarity and genetic distances when compared with those of 16S rRNA, and the molecular differences were statistically significant (Student t-test, p<0.05). Parsimony analyses showed the rpoB gene evolves more than 2-fold faster than 16S rRNA. In addition, phylogeny of the rpoB gene separated each M. aeruginosa strain more clearly compared with a 16S rRNA tree. This study found that the order Chroococcales, including Microcystis, has approximately two rRNA operons and single copy of the rpoB gene in their chromosomes. These results suggest that the rpoB gene is a useful marker for the molecular phylogenetics and the detection of Microcystis.

• ALGAE
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• v.38 no.4
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• pp.217-240
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• 2023

Sulfated polysaccharides (SPs) isolated from seaweed have emerged as remarkable bioactive compounds with a wide spectrum of biological activities and have substantial value in the scientific and industrial domains. The current study explores the diverse biological activities of SPs and their relationship with their structures. This aids in an in-depth examination of the multifaceted biological activities of SPs, including anticoagulant, anti-inflammatory, antiviral, antioxidant, and immunomodulatory properties, which underpin their potential health benefits. Furthermore, the current study explores the complicated properties of SPs, with their extraction methodologies and techniques for precise characterization. Elucidation of the commercial significance of SPs derived from brown, red, and green seaweed by highlighting their potential applications has emphasized their importance in human well-being. Further, this review emphasizes the challenges needed to overcome research and industrial innovations for SPs. Collaboration among researchers, industry stakeholders, and regulatory authorities can overcome these challenges and elevate the potential of SPs to revolutionize industries such as pharmaceuticals, cosmeceuticals, food, and biotechnology.