• Membrane Journal
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• v.16 no.1
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• pp.68-76
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• 2006

This is the research about the concentration of trace citrus flavor components in water by pervaporation. We have investigated the permeation characteristics depending on the material and formation of membranes using four siloxane-based polymer composite membranes. We have also chosen the optimal membrane and investigated the permeation characteristics depending on the feed temperature, concentration and flow rate. And then it has been analyzed by using resistance-in series model. In the permeation experiment of citrus essence aroma model solution through the four siloxane-based polymer composite membranes, PVDF/POMS membranes have showed the best flavor flux and enrichment factor. As a result of the permeation experiment depending on the feed temperature, concentration and flow rate, we can find that as the feed temperature and concentration increase, the flavor flux increases while the enrichment factor decreases. And the flavor flux and enrichment factor increased as the flow rate increases.

• Journal of Korea Trade
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• v.25 no.5
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• pp.93-109
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• 2021

Purpose - The logistics industry is often featured by its location relevance and industrial concentration. Industrial concentration is conducive to the effective transmission of information by reducing transaction costs and improving transaction efficiency, thus promoting the development of trade. The main purpose of this paper is to measure the spatial total factor productivity and location quotient of the logistics industry in Korea, and to study the impact of the logistics industry efficiency and agglomeration effect on import and export trade in Korea. Design/methodology - First, used the spatial stochastic frontier method to measure the spatial total factor productivity of the logistics industry in Korea, this serves as the efficiency index of the logistics industry in various regions of Korea. Second, calculated the location quotient (LQ) of the logistics industry to measure the industry's concentration degree. Third, employed a spatial econometric model to analyze the impacts of factors such as the efficiency and concentration levels of the logistics industry on import and export trade in Korea. Findings - This study's main findings can be summarized as follows: this study found that the overall efficiency of the logistics industry in Korea needs to be improved, even though it showed an upward trend in all regions of the country; Moreover, the agglomeration level of Korea's logistics industry needs to be improved; Finally, the positive spatial correlation and industrial agglomeration effect of Korea's logistics industry had a positive impact on the country's import and export trade. Originality/value - This study is innovative in terms of research perspective and methods. Most of the previous studies have measured the development level of the logistics industry using the logistics performance index (LPI), Fewer studies have assessed through the spatial total factor productivity and location quotient of the logistics industry in Korea to measure the efficiency index of the logistics industry in various regions of Korea and concentration degree, as well as there was almost no study on the impact of logistics industry efficiency and agglomeration effect on import and export trade in Korea. This study addresses this limitation by analyzing the impacts of the efficiency and agglomeration effect of the logistics industry on import and export trade in Korea.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2019.10a
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• pp.63-63
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• 2019

The thinning Green ball apple was extracted using water and ethanol and a phenolic concentration of thinning Green ball apple was $50-200{\mu}g/mL$. The water and ethanol extracts of thinning Green ball apple showed 94.69% and 92.24% 1,1-diphenyl-2-picrylhydrazyl radical scavenging activity and 100.30% and 99.16% 2,2'-Azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) radical scavenging activity at phenolic concentration of $200{\mu}g/mL$, respectively. The water and ethanol extracts of thinning Green ball apple showed antioxidant protection factor of 1.76 antioxidant protection factor and 1.76 antioxidant protection factor, respectively. The water and ethanol extracts showed 101.46% and 99.64% anti-oxidative effect on thiobarbituric acid reactive substances at phenolic concentration of $200{\mu}g/mL$. Hence, the water and ethanol extracts of thinning Green ball apple can be considered a potential anti-oxidant. The water and ethanol extracts showed 33.28% and 32.14% hyaluronidase inhibition, respectively, at phenolic concentration of $150{\mu}g/mL$. The water and ethanol extracts showed 47.33% and 40.92% elastase inhibition and 46.19% and 65.58% collagenase inhibition at phenolic concentration of $200{\mu}g/mL$, respectively. About these experiments, thinning Green ball apple was found to exhibit anti-oxidation activity as well as hyaluronidase, elastase and collagenase inhibitory activities. Therefore, thinning Green ball apple can be considered a potential source for functional food.

• Current Applied Physics
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• v.18 no.12
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• pp.1513-1522
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• 2018

Bismuth telluride ($Bi_2Te_3$) thin films were prepared with various electrolyte temperatures ($10^{\circ}C-70^{\circ}C$) and concentrations [$Bi(NO_3)_3$ and $TeO_2:1.25-5.0mM$] in this study. The surface morphologies differed significantly between the experiments in which these two electrodeposition conditions were separately adjusted even though the applied current density was in the same range in both cases. At higher electrolyte temperatures, a dendrite crystal structure appeared on the film surface. However, the surface morphology did not change significantly as the electrolyte concentration increased. The dendrite crystal structure formation in the former case may have been caused by the diffusion lengths of the ions increasing with increasing electrolyte temperature. In such a state, the reactive points primarily occur at the tops of spiked areas, leading to dendrite crystal structure formation. In addition, the in-plane thermoelectric properties of $Bi_2Te_3$ thin films were measured at approximately 300 K. The power factor decreased drastically as the electrolyte temperature increased because of the decrease in electrical conductivity due to the dendrite crystal structure. However, the power factor did not strongly depend on the electrolyte concentration. The highest power factor [$1.08{\mu}W/(cm{\cdot}K^2$)] was obtained at 3.75 mM. Therefore, to produce electrodeposited $Bi_2Te_3$ films with improved thermoelectric performances and relatively high deposition rates, the electrolyte temperature should be relatively low ($30^{\circ}C$) and the electrolyte concentration should be set at 3.75 mM.

• Journal of Physiology & Pathology in Korean Medicine
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• v.24 no.4
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• pp.586-591
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• 2010

Chemokine and Growth Factor are major mediumtors of immuno-inflammatory pathway. The purpose of this study is to investigate whether productions of Chemokine and Growth Factor in lipopolysaccharide (LPS)-induced mouse macrophage RAW 264.7 cells are modulated by Gallic acid (GA), which is easily founded in tannin-containing natural materials such as red wine, green tea, grape juice, and Corni Fructus. Productions of Chemokine and Growth Factor were analyzed by High-throughput Multiplex Bead based Assay with Bio-plex Suspension Array System based on $xMAP^{(R)}$ (multi-analyte profiling beads) technology. At first, cell culture supernatant was obtained after treatment with LPS and GA for 24 hour. Then, the antibody-conjugated beads were added and incubated for 30 minutes. After incubation, detection antibody was added and incubated for 30 minutes. And Strepavidin-conjugated Phycoerythrin (SAPE) was added. After incubation for 30 minutes, the level of SAPE fluorescence was analyzed on Bio-plex Suspension Array System. Based on fluorescence intensity, concentrations of Chemokine and Growth Factor were determined. The results of the experiment are as follows. GA significantly inhibited the production of interferon-inducible protein (IP)-10, keratinocyte-derived chemokine(KC), and vascular endothelial growth factor (VEGF) in LPS-induced RAW 264.7 cells at the concentration of 25, 50, 100, 200 uM (p<0.05). GA significantly inhibited the production of monocyte chemoattractant protein-1(MCP-1) and macrophage-colony stimulating factor(M-CSF) in LPS-induced RAW 264.7 cells at the concentration of 50, 100, 200 uM (p<0.05). GA diminished the production of granulocyte macrophage-colony stimulating factor (GM-CSF) in LPS-induced RAW 264.7 cells. But GA did not show the inhibitory effect on the production of leukemia inhibitory factor (LIP) and macrophage inflammatory protein (MIP)-2 in LPS-induced RAW 264.7 cells. These results suggest that GA has the immuno-modulating activity related with its inhibitory effects on the production of IP-10, KC, MCP-1, VEGF, and M-CSF in LPS-induced macrophages.

• Journal of Environmental Health Sciences
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• v.2 no.1
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• pp.29-31
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• 1975

This experiment Was carried out under two points of view, from May 1st to the end of 1973. One was the comparative determination of the activation factor of Lead dioxide by kinds in measuring of Sulfur oxides concentration by $PbO_2$ cylinder method, and the other was the comparison that result with the record of auto analyzer. Five measuring sites were selected out of Seoul City. Three kinds of Lead dioxide made in Japan (B,C and D) were compared with Standard $PbO_2$ (A for use in Determination of Sulphur in the atmosphere, purity 99% up) made in British Institution, and monthly measuring was conducted at every sampling site. The recording by auto analyzer (Beckman Model 906-A $SO_2$ Analyzer) was conducted once or twice a month for 24 hours at each sampling site during the same period. And some significant results were obtained. 1. In comparative experiments to determine the activation degree of three kinds of Lead dioxide (B,C and D), the obtained correction factor of B reagent was 1.09, 1.16 in C and 1.30 in D against Standard $PbO_2$ (A). Therefore, it should be in need of standardization or clear statement about the reagents for use, in determination sulfur oxides by $PbO_2$ cylinder method. 2. Generally, the concentration of Sulfur dioxide by wilkins' convertion method from $SO_3$ showed about 20-30% higher than those by Auto analyzer.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.28 no.2
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• pp.92-100
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• 2016

Reliability analysis of tripod support structure for offshore wind turbine was performed. Extreme distribution function of peak response due to wind and wave loads was estimated by applying peak over threshold(POT) method. Then, stress based limit state function was defined by using maximum stress of support structure which was obtained by multiplying beam stress and concentration factor. The reliability analysis result was compared when maximum stress was calculated from shell element. Reliability index was evaluated using first order reliability method(FORM).

• Journal of the Korean Applied Science and Technology
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• v.13 no.3
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• pp.95-103
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• 1996

In the separation of toluene/n-heptane mixture by the emulsion type liquid membrane in an batch system, the effect of surfactant on the separation factor and membrane stability was studied over the surfactant concentration ranging form 0.1 to 1.5wt％ at the contact time of 5 and 10 minutes. and the settling time of 5 and 10 minutes. The surfactant used was sodium lauryl sulfate. The separation factor reached its maximum value at the surfactant concentration of 0.5wt％ for surfantant. It was found that the percentage of membrane breakup reached its minimum values and the separation factor showed its maximum value at the surfactant concentration of 0.5wt%. which confirmed that efficient separation could be effect when emulsion liquid membrane was stable because of low membrane breakup.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.12 no.4
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• pp.63-69
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• 2003

In discontinuous composite mechanics, shear lag theory is one of the most popular model because of its simplicity and accuracy. However, it does not provide sufficiently accurate strengthening predictions in elastic regime then the fiber aspect ratio is small. This is due to its neglect of stress transfer across the fiber ends and the stress concentrations that exist in the matrix regions near the fiber ends. To overcome this shortcoming, a more simplified shear lag model introducing the stress concentration factor which is a function of several variables, such as the modulus ratio, the fiber volume fraction, the fiber aspect ratio, is proposed. It is found that the modulus ratio($E_f$/$E_m$) is the essential variable among them. Thus, the stress concentration factor is expressed as a function of modulus ratio in the derivation. It is found that the proposed model gives a good agreement with finite element results and has the capability to correctly predict the values of interfacial shear stresses and local stress variations in the small fiber aspect ratio regime.

• Analytical Science and Technology
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• v.9 no.4
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• pp.406-410
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• 1996

The adsorption behaviors of transition metal ions on the poly(N,N'-bispalmitoyl-1, 12-diaza-3, 4;9,10-dibenzo-5,8-cyclopentadecane) has been determined by adsorption process in aqueous solution. The order of concentration factor(CF) and the amount of adsorption were Cu(II)