• Composites Research
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• v.18 no.4
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• pp.27-34
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• 2005

Salt water spray and immersion tests were experimentally conducted for over 6 months to investigate the durability of glass fabric/phenolic composites under salt water environment. Mechanical properties such as tensile properties, flexural properties, and shear properties were evaluated and thermal analysis properties such as storage shear modulus, loss shear moduls, and tan 6 were obtained through a DMA. A change in chemical structures was analyzed through a FTIR. According to the results, mechanical properties and thermal analysis properties were sensitive to salt water environment and these properties began to degrade in increasing in exposure times. However, tensile and flexural moduli started to decrease and then slightly increase as increasing in exposure times due to plasticization and crosslinking in matrix as well as physical swelling in composites. Beyond a certain exposure times, these properties began to decrease as further increasing in exposure times. Also the shape and location of peaks in FTIR curves were insensitive to exposure times, but the intensity of peaks would be. finally we found that the durability of glass fabric/phenolic composites were affected on salt water immersion environment rather than salt water spray environment.

• International Union of Geodesy and Geophysics Korean Journal of Geophysical Research
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• v.22 no.1
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• pp.1.1-15
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• 1994

The transports of the seasonal freshwater and salt from surface to 500 m depth in the tropical Atlantic Ocean are derived from the equations of the continuity and saltconservation, respectively. The freshwater transport is obtained by southward integration of the divergence of surface freshwater flux, using climatological freshwater(i. e. precipitation, evaporation, and river discharge) data. The annual freshwater transport is northward, ranging from 0 Sv near the equator to 0.3 Sv at $12^{\circ}{\;}N{\;}and{\;}20^{\circ}{\;}S$. The seasonal meridional transport amounts of freshwater range from 1.35 Sv to-0.45 Sv. The strong northward freshwater transports prevail for the intraseasonal period summer to fall. This seasonal cycle is caused by the shifts of the ITCZ as well as the changes in the local freshwater storage. Annual and seasonal salt transports are calculated from objectively analyzed historical (1900-86) salinity observations. The annual salt flux in the ocean zero, showing that the salt flux by horizontal advection balances the flux by horizontal diffusion. The salt flux due to the diffusion is northward, and has a maximum of $5{\;}{\times}{\;}10^6kg/s$ at 15oN. Seasonal transport amounts of salt range from $30{\;}{\times}{\;}10^6kg/s{\;}to{\;}-35{\;}{\times}10^6kg/s$. The direction of the seasonal salt transports is northward except for the intraseasonal period summer to fall.

• Journal of Ecology and Environment
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• v.35 no.2
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• pp.123-129
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• 2012

Salt marsh is an important transitional zone among terrestrial, riverine, and marine ecosystems and is a productive habitat that interacts extensively with adjacent landscape elements of estuarine and coastal ecosystems. Nowadays, in addition to various human activities, a variety of natural processes induce changes in salt marshes. This study aims to provide background information to restore disturbed salt marshes and to propose their ecological restoration using seed banks. The study area is a prepared area for the Gwangyang Container Port located in the southern Korea. This area was formed by accumulating mud soils dredged from the bottom of the forward sea. This land was created in a serial process of preparing the Gwangyang container port and the salt marsh was passively restored by seeds buried in mud soil dredged from seabed. As a result of stand ordination based on vegetation data collected from the land, stands were arranged according to tolerance to salinity in the order of $Suaeda$ $maritima$, $Salicornia$ $europaea$, and $Phragmites$ $communis$ communities on the Axis 1. Landscape structure of the projected area was analyzed as well. Edges of the projected area were divided from the marginal waterway by the dike. Four types of vegetation appeared on the dike: $Alnus$ $firma$ plantation, $Robinia$ $pseudoacacia$ plantation, $Lespedeza$ $cyrtobotrya$ plantation, and grassland. In the more internal areas, two types of vegetation sequences appeared: $Aster$ $tripolium$ community-$Suaeda$ $glauca$ community-$Salicornia$ $europaea$ community sequence and $Aster$ $tripolium$ community-$Suaeda$ $maritima$ community-$S.$ $europaea$ community sequence. Mixed community showed the highest species diversity (H' = 0.86) and $S.$ $europaea$ community showed the lowest (H' = 0.0). Evenness is the highest in Mixed community (J' = 2.26) and the lowest in $S.$ $maritime-S.$ $europaea$ community (J' = 0.0). Several plant communities were successfully established on the land created by mud soil dredged from the bottom of Gwangyang Bay. Moreover, community diversity in this area approached a similar level with those from other studies involving natural salt marshes. Therefore, restoration effect based on community diversity obtained in our study can be evaluated as a successful achievement. In this respect, although most salt marshes in Korea and other places worldwide have been destroyed or disturbed by excessive land use, feasibility of seed bank as a restoration tool is greatly expected.

• Journal of Korean Medicine for Obesity Research
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• v.18 no.2
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• pp.106-114
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• 2018

Objectives: We investigated about the microbial properties and changes in the efficacy of the Codonopsis lanceolata (CL) by natural fermentation. Methods: CL was fermented for four weeks in a well-ventilated place with 2.5% salt. pH, total sugar, total polyphenol, and total flavonoid were measured to determine fermentation characteristics according to fermentation period and salt treatment. Polymerase chain reaction denaturing gradient gel electrophoresis and random amplification of polymorphic DNA-polymerase chain reaction were carried out for microbial analysis during fermentation. In addition, HepG2 cell was cultured to check the lipid accumulation through oil red O staining and the glucose uptake was analyzed by measuring the 2-NBDG at C2C12 cell. Results: The pH level and the total sugar decreased with the CL fermentation. Total polyphenol and flavonoid increased after CL fermentation. It was confirmed that Leuconostoc mesenteroides were maintained continuously during fermentation. In the salt treatment CL, there was a sharp increase in Rahnella aquatilis. Lactobacillus plantarum matrix was observed in fermented CL. In addition, Lactococcus lactis, Weissella koreensis, R. aquatilis, L. plantarum, Leu. mesenteroides have been added to the salt treatment. Glucose uptake were significantly increased after fermentation with salt for four weeks. Lipid accumulation in the HepG2 cells was observed that there was difference (P<0.01) between free fatty acid group (100%) and decreased 4 weeks after fermentation (90.38%) at $800{\mu}g/mL$. Conclusions: Total polyphenol and flavonoid were increased after CL fermentation. Especially, percentage of the glucose uptake and lipid accumulation inhibition increased in CL fermentation with salt. It is expected that fermentation of salt treated CL will be more effective in diabetes and fatty liver.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.34 no.3
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• pp.859-871
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• 2014

In order to analyze the density current due to salt and temperature difference, this study develops new numerical model (LES-WASS-3D ver. 2.0) by introducing state equation for salt and temperature and 3D advection-diffusion equation to existing 3D numerical wave tank (LES-WASS-3D ver. 1.0). To verify the applicability, the newly-developed numerical model is analyzed comparing to the experimental result of existing numerical model. In the result, it well implement the behavior and vertical salt concentration of advected and diffused seawater as well as flow velocity and temperature of the discharged warm water. This confirms the validity and effectiveness of the developed numerical model.

• Macromolecular Research
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• v.15 no.2
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• pp.167-172
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• 2007

The reduction behavior of silver ions to silver nanoparticles is an important topic in polymer/silver salt complex membranes to facilitate olefin transport, as this has a significant effect on the long-term performance stability of the membrane. In this study, the effects ofthe solvent type on the formation of silver nanoparticles, as well as the long-term membrane performance of a solid polymer/silver salt complex membrane were investigated. These effects were assessed for solid complexes of poly(N-vinyl pyrrolidone) $(PVP)/AgBF_4$, using either an ionic liquid (IL), acetonitrile (ACN) or water as the solvent for the membrane preparation. The membrane performance test showed that long-term stability was strongly dependent on the solvent type, which increased in the following order: IL > ACN >> water. The formation of silver nanoparticles was more favorable with the solvent type in the reverse order, as supported by UV-visible spectroscopy. The poor stability of the $(PVP)/AgBF_4$ membrane when water was used as the solvent might have been due to the small amount of water present in the silver-polymer complex membranes actively participating in the reduction reaction of the silver ions into silver nanoparticles. Conversely, the higher stability of the $(PVP)/AgBF_4$, membrane when an IL was used as the solvent was attributable to the cooperative coordination of silver ions with the IL, as well as with the polymer matrix, as confirmed by FTIR spectroscopy.

• Journal of Industrial and Engineering Chemistry
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• v.68
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• pp.14-23
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• 2018

$TiO_2-coated$ cubic ${\alpha}-Fe_2O_3$ with mostly exposed (012) and (101) facets (${\alpha}-Fe_2O_3@TiO_2$) was fabricated using a hydrothermal route for the photo-Fenton degradation of tetracycline under visible light irradiation. $TiO_2$ coating could greatly affect the photocatalytic activity of ${\alpha}-Fe_2O_3@TiO_2$. Compared with cubic ${\alpha}-Fe_2O_3$ alone for photodegradation of tetracycline, ${\alpha}-Fe_2O_3@TiO_2$ with $TiO_2$ shell of around 15 nm exhibited higher removal efficiency of tetracycline in photo-Fenton system, and its durability was slightly affected after five cycle times under same conditions. It is ascribed to the well-matched interface between cubic ${\alpha}-Fe_2O_3$ core and $TiO_2$ shell, leading to the broadened light-absorption and the efficient separation of photo-generated electon-hole pairs. The $^{\bullet}OH$ radicals were main responsible for the advanced photocatalytic performance of ${\alpha}-Fe_2O_3@TiO_2$ in visible-light driven degradation of tetracycline.

• Journal of Food Hygiene and Safety
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• v.11 no.3
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• pp.171-176
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• 1996

Microbial distribution as well as content of salt and preservatives in side dishes was investigated by analyzing cell count of viable cells, coliform bacteria and food poisoning bacteria of sliced squid bokum and anchovy bokum, purchased at 17 different department stores and 2 different traditional market in Seoul, which are most preferred by many consumers to any other side dishes available in the market. 6.2$\times$103~1.2$\times$108 cells/g of viable cell was detected in 19 different samples of the sliced squid bokum, among which samples of the sliced squid bokum and 14 samples of the anchovy bokum contained 103~108 cells/g of coliform group. However food poisoning bacteria were not detected in all the samples tested. Salt content was 2.42~4.89 %w/w and 2.28~6.46 w/w for the sliced squid bokum and the anchovy bokum respectively. Analysis of preservatives by HPLC such as sorbic acid, benzoic acid, dehydroacetic acid and another 6 kinds of esters resulted that 1.0$\times$73.8 mg/100 g of sorbic acid was detected in the 19 samples of the sliced squid bokum, while only 6 samples of the 15 anchovy bokum samples contained sorbic acid.

• Journal of Korean Society for Atmospheric Environment
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• v.20 no.2
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• pp.143-151
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• 2004

The chemical composition of PM$_{2.5}$ was measured at Gosan, Jeju for two weeks each in November 2001 and spring 2002. In the latter part of the measurement period of November 2001, designated as the polluted period in this work, secondarily formed ion components as well as primarily emitted elemental carbon were high. PM$_{2.5}$ mass concentration was also high in this polluted period compared with the yellow sand period, in which daily average of PM $_{10}$ peaked up to 520 $\mu\textrm{g}$/㎥. Increase of major components of anthropogenic origin in the polluted period was not correlated with the variation in sea salt components while increase of crustal components in the yellow sand period was highly correlated with the variation in sea salt components. Trace elements were generally higher in the yellow sand period; however, toxic heavy metals such as zinc, cadmium and lead were the highest in the polluted period.d.d.d.

• Applied Chemistry for Engineering
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• v.9 no.2
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• pp.261-267
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• 1998

We have investigated the stability of macroemulsions of AOT prepared from Winsor systems. The emulsion system was prepared from heptane+aqueous NaCl+AOT. As the concentration of NaCl increases, the stability of the emulsion increases, reaches a maximum, and then decreases. At low salt concentration the creaming occurred due to density difference of oil and aqueous phases. We developed a model for the creaming. Behavior of the emulsions containing low salt could be described very well by the model, however, at high salt concentration the electrostatic repulsion decreased due to screening and droplets started to attract each other and the stability of the emulsion decreased.