• Journal of the Korean Chemical Society
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• v.36 no.6
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• pp.914-918
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• 1992

The preferential transport phenomena of neutral cation-anion moieties in neutral macrocycle-facilitated emulsion liquid membrane were described in this study. Emulsion membrane systems consisting of (1) aqueous source phase containing 0.001M $M(NO_3)_2$ (M = $Mn^{2+}$, $Co^{2+}$, $Ni^{2+}$, $Cu^{2+}$, $Zn^{2+}$, $Sr^{2+}$, $Cd^{2+}$, $Pb^{2+}$) (2) a toluene membrane containing 0.02M ligand (DB$N_3O_2$, DB18C6) and the surfactant span 80 (sorbitan mono oleate) (3% v/v) and (3) aqueous receiving phase containing $Na_2S_2O_3$ or $NaNO_3$ were studied with respect to the disappearence of metal ions from the source phase as a function of time. Cation transport rates for various two component equimolar mixture of metal ions were determinded. $Cd^{2+}$ was transported higher rates than the other $M^{2+}$ in the mixture solution.

• Journal of Astronomy and Space Sciences
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• v.29 no.3
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• pp.253-258
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• 2012

We revisit the relation between the peak luminosity $L_{iso}$ and the spectral time lag in the source frame. Since gamma-ray bursts (GRBs) are generally thought to be beamed, it is natural to expect that the collimation-corrected peak luminosity may well correlate with the spectral time lag in the source frame if the lag-luminosity relation in the GRB source frame exists. With 12 long GRBs detected by the Swift satellite, whose redshift and spectral lags in the source frame are known, we computed $L_{0,H}$ and $L_{0,W}$ using bulk Lorentz factors ${\Gamma}_{0,H}$ and ${\Gamma}_{0,W}$ archived in the published literature, where the subscripts H and W represent homogeneous and wind-like circumburst environments, respectively. We have confirmed that the isotropic peak luminosity correlates with the spectral time lag in the source frame. We have also confirmed that there is an anti-correlation between the source-frame spectral lag and the peak energy, $E_{peak}$ (1 + z) in the source frame. We have found that the collimation-corrected luminosity correlates in a similar way with the spectral lag, except that the correlations are somewhat less tight. The correlation in the wind density profile seems to agree with the isotropic peak luminosity case better than in the homogeneous case. Finally we conclude by briefly discussing its implications.

• Transactions of the Korean Society of Mechanical Engineers
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• v.16 no.1
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• pp.175-179
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• 1992

Generally speaking, natural gas possesses several characteristics that make it desirable as an engine fuel : for example (1) lower production cost, (2) abundant commodity and (3) cleaner energy source than gasoline. Due to the physical characteristics of natural gas, the volumetric efficiency and flame speed of a natural gas engine are lower than those of a gasoline engine, which results in a power loss of 10-20% when compared to a convensional gasoline engine. This paper describes the results of a research to improve the performance of a natural gas engine through the modification and controls of air/fuel ratio, spark timing advance and supercharging effect by forced air supply method.

• Korean Institute of Interior Design Journal
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• no.17
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• pp.52-59
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• 1998

In the modern ages when the surroundings of a city has become firm and monotonous this study designed to suggest an direction towards creative approaches to space planning by analyzing the images of interior space with the introduction of natural expressions as an alternative to create original space in order to give vitality to the previous standardized space and to satisfy human beings psychological desire. The results of the analysis as a way of expressing direct indirect and eclectic images using nature a source of arts read that most of the natural expressions show perceptive images strongly that natural elements can become the elements of design in any form and that nature's images are expressed by not only natural and artificial materials. In conclusion natural expression in interior space does not have any fixed form of expression but gives a great deal of vocabulary to the image formation of interior space by stimulating being's sentiment with the spatial restructure of nature's own particular order of form.

• Natural Product Sciences
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• v.13 no.4
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• pp.332-336
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• 2007

Five steroids and two norsesquiterpene glycosides were isolated from the methanol extract of H. japonicus. Their structures were determined by means of physio-chemical and spectral data to be friedelin (1), stigmast-5-en-3-${\beta}$-ol (${\beta}$-sitosterol) (2), 7-keto-${\beta}$-sitosterol (3), 6${\beta}$-hydroxy-4-stigmasten-3-one (4), 7${\alpha}$-hydroxy-${\beta}$-sitosterol (5), 3-hydroxy-4,4-dimethyl-4-butyrolactone (6), daucosterol (7), (6S, 9S)-roseoside (8), and (9S)-drummondol-9-O-${\beta}$-D-glucopyranoside (spinoside B) (9). The compounds 1, 3, 4, and 6 - 9 were first isolated from this plant source.

• Proceedings of the Korean Society of Life Science Conference
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• 2001.02a
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• pp.57-57
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• 2001

• The Korean Journal of Ecology
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• v.25 no.1
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• pp.1-7
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• 2002

The ecological background of a restoration project is complex and difficult to betermine without experimentation. A useful context for experiments is the well-studied process of natural succession, because the factors that drive or inhibit succession are also at work during reclamation (a form of primary succession) and restoration (which often resembles secondary succession). Using experimental studies on urban wasteland reclamation, we have tested for factors that stimulate or inhibit succession during early phases of woodland development in the Northeastern United states. The emphasis has been on mutualisms (seed dispersal, pollination, and mycorrhizae) and microsite limitations in the recruitment, growth, and reproduction of woody plants. Using plantings of seeds, seedlings, and clusters of reproductively mature plants on abandoned landfills, we have observed that (1) soil microsite deficiencies lead to very poor germination (<0.1$\%$) and seedling survival (<0.01$\%$) of most native species; (2) seed dispersal by birds is a significant and reliable source of woody plant recruitment; however (3) proximity effects are strong, with most (up to 95$\%$) of seed rain falling in the vicinity of planted clusters that are closest to putative seed sources; and (4) remnant natural woodlands are critical components of the recruitment process. To emphasize the last point, in one case, we found that the destruction of approximately 50$\%$ of nearby natural woodland vegetation led to a commensurate decline in seed rain. In another case, we found that the species richness of recruits was strictly limited by the species composition of nearby source plant communities, with no evidence of community enrichment by long distance dispersal over 5 years. We conclude from these results that the size and proximity of remnant natural populations are critical considerations when planning reclamation and restoration programs that rely on natural successional processes.

• Natural Product Sciences
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• v.24 no.2
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• pp.132-138
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• 2018

Phytochemical investigation of 80% MeOH extract of the aerial parts of Capsella bursa-pastoris yielded fourteen compounds (1 - 14). The structures of the compounds were elucidated by spectroscopic methods to be methyl-1-thio-${\beta}$-D-glucopyranosyl disulfide (1), 10-methylsulphinyl-decanenitrile (2), 11-methyl-sulphinyl-undecanenitrile (3), 1-O-(lauroyl)glycerol (4), phytene-1, 2-diol (5), (3S,5R,6S,7E)-5,6-epoxy-3-hydroxy-7-megastigmen-9-one (6), loliolide (7), ${\beta}$-sitosterol (8), 3-hydroxy-1-(4-hydroxy-3-methoxyphenyl)-1-propanone (9), 1-feruloyl-${\beta}$-D-glucopyranoside (10), pinoresinol-4'-O-${\beta}$-D-glucopyranoside (11), luteolin (12), quercetin-3-O-${\beta}$-D-glucopyranoside (13), and luteolin 6-C-${\beta}$-glucopyranoside (14). Although compound 1 was reported as synthetic compound, 1 was first isolated from natural source. NMR spectral data assignments of 1, 2 and 3 were reported for the first time, and compounds 1 - 14 were for the first time reported from this plant source. The anti-inflammatory effects of 1 - 14 were evaluated in lipopolysaccharide (LPS)-stimulated murine microglia BV-2 cells. Compounds 12 exhibited strong inhibitory effects on nitric oxide production in LPS-activated BV-2 cells with $IC_{50}$ values of $9.70{\mu}M$.

• Journal of Environmental Science International
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• v.19 no.1
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• pp.17-26
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• 2010

To understand the initial changes in the microbial activities of wetland soil after construction, dehydrogenase activity (DHA) and denitrification potential (DNP) of soil from 1 natural wetland and 2 newly constructed wetlands were monitored. Soil samples were collected from the Daepyung marsh as a natural wetland, a treatment wetland in the West Nakdong River, and an experimental wetland in the Pukyong National University, Busan. The results showed that the DHA of the natural wetland soil was 6.1 times higher than that of the experimental wetland and similar to that of the treatment wetland 6 months after wetland construction (fall). Few differences were observed in the DNP between the soil samples from the natural wetland and 2 constructed wetlands four months after wetland construction (summer). However, 6 months after the construction (fall), the DNP of the soil samples from the natural wetland was 12.9 times and 1.8 times higher than that of the experimental wetland and the treatment wetland, respectively. These results suggested that the presence of organic matter as a carbon source in the wetland soil affects the DHA of wetland soil. Seasonal variation of wetland environment, acclimation time under anaerobic or anoxic wetland conditions, and the presence of carbon source also affect the DNP of the wetland soil. The results imply that the newly constructed wetland requires some period of time for having the better contaminant removal performance through biogeochemical processes. Therefore, those microbial activities and related indicators could be considered for wetland management such as operation and performance monitoring of wetlands.

• Journal of Environmental Science International
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• v.24 no.10
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• pp.1239-1251
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• 2015

Impervious areas have been expanded by urbanization and the natural structure of water circulation has been destroyed. The limits of centralized management for controlling storm water runoff in urban areas have been suggested. Low impact development (LID) technologies have been promoted as a crucial alternative, establishing a connection with city development plans to build green infrastructures in environmentally friendly cities. Thus, the improvement of water circulation and the control of nonpoint source were simulated through XP-SWMM (storm water and wastewater management model for experts) in this study. The application of multiple LID combination practices with permeable pavements, bioretention cells, and gutter filters were observed as reducing the highest runoff volume by up to 70%. The results from four different LID installation scenarios indicated that permeable paving is the most effective method for reducing storm water runoff. The rate of storm water runoff volume reduced as the rainfall duration extended. Based on the simulation results, each LID facility was designed and constructed in the target area. The LID practices in an urban area enable future studies of the analysis of the criteria, suitable capacity, and cost-efficiency, and proper management methods of various LID techniques.