• Journal of the Korean Electrochemical Society
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• v.15 no.2
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• pp.109-114
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• 2012

The cathode catalyst layer in polymer electrolyte membrane fuel cells (PEMFCs) was fabricated with anodic aluminum oxide (AAO) template and its structure was characterized with scanning electron microscopy (SEM) and Brunauer-Emmett-Teller (BET) analysis. The SEM analysis showed that the catalyst layer was fabricated the Pt nanowire with uniform shape and size. The BET analysis showed that the volume of pores in range of 20-100 nm was enhanced by AAO template. The electrochemical properties with the membrane electrode assembly (MEA) were evaluated by current-voltage polarization measurements and electrochemical impedance spectroscopy. The results showed that the MEA with AAO template reduced the mass transfer resistance and improved the cell performance by approximately 25% through controlling the structure of catalyst layer.

• Journal of the Korea Institute of Building Construction
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• v.16 no.3
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• pp.219-227
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• 2016

Chloride ions ingress continuously in reinforced concrete through pores of it by $Cl^-$. Finally, it causes a localized corrosion of the rebar and then it generates cracks on concrete structures. Recently, new materials removing harmful anions have been developed. Layered double hydroxides(LDHs) has an excellent ability to remove harmful anions because various anions can be adsorbed in the interlayer space between divalent and trivalent cations. Thus, LDHs has been applied in various fields. Especially, LDHs is expected to be effective adsorbent binding chloride ions. In this study, $Ca/Al-NO_3$ and $Mg/Al-NO_3$ LDHs were prepared by using a co-precipitation method. $Ca/Al-NO_3$ and $Mg/Al-NO_3$ LDHs were compared and analyzed by using XRD, SEM analysis. Many nano size hexagonal crystals were observed by SEM. Experiments for binding chloride ions of LDHs were conducted by using potentiometric method. The experimental data were measured every 15 minutes. It was observed that the chloride ion content is reduced by increasing of LDHs mass fraction and the reaction rate of $Mg/Al-NO_3$ is faster than $Ca/Al-NO_3$. In future studies, binding chloride capacity in cement materials will be evaluated based on results of this study.

• KSBB Journal
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• v.14 no.1
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• pp.114-118
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• 1999

In order to use a polysaccharide, curdlan, as a concrete admixture, we first developed a pilot-scale fermentation process for the mass production of curdlan. We also examined the rheological properties of curdlan, and tested how well the curdlan obtained in this work increased the segregational resistance of the cement slurry. Fermentation was performed in a 300-liter fermenter equipped with 3 disk-turbine impellers. Since curdlan production is stimulated under nitrogen-limiting conditions, the culture pH was shifted from the optimal pH for cell growth (pH 7.0) to the optimal pH for curdlan production (pH 5.5) at the onset of ammonium exhaustion. We obtained a curdlan production of 65 g/L in 120 hr batch cultivation of Agrobacterium species. The insoluble curdlan at the final stage of fermentation was readily harvested by centrifugation together with the cells. The freeze-dried sample contained 78% (w/w) of curdlan. The solubility and viscosity of the curdlan increased with the increase of the solution pH, which enhances the viscosity of concrete since the pH of concrete is extremely high (pH 13.0). Test results of the curdlan as a concrete admixture with cement slurry demonstrated that it prohibits the leakage of water. In conclusion, this work certifies and enlarges curdlan's industrial potential as a concrete admixture.

• Journal of the Korean Society of Food Science and Nutrition
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• v.42 no.1
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• pp.26-32
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• 2013

Boesenbergia pandurata (Roxb.) Schltr. has been reported to possess anti-oxidative and anti-inflammatory properties. The aim of this study was to investigate the effect of Boesenbergia pandurata extract (BPE) in a high-fat diet (HFD)-induced obese mice model. C57BL/6J mice were fed with either the high-fat diet or a 0.5% BPE-supplemented HFD for 8 weeks. The BPE-containing HFD significantly reduced body weight gain and the accumulation of visceral fat mass in mice model without altering the amount of food intake. Moreover, mice fed with BPE-containing HFD had lower concentrations of lipids in their blood, lower hepatic lipid accumulation, and lower serum leptin levels compared with the HFD-fed mice. RT-PCR analysis showed that the expression levels of peroxisome proliferators-activated receptor ${\gamma}2$ ($PPAR{\gamma}2$) and CCAT/enhancer binding protein ${\alpha}$ ($C/EBP{\alpha}$) genes in the epididymal fat tissue of mice fed the BPE-containing HFD increased 1.16- and 1.30-fold, respectively, compared to mice fed HFD only. In conclusion, BPE attenuated visceral fat accumulation and improved dyslipidemia in a mice model with HFD-induced obesity.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.35 no.1
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• pp.23-31
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• 2011

At supercritical pressure, the physical properties of fluid change substantially and the heat transfer at a temperature similar to the critical or pseudo-critical temperature improves considerably; however, the heat transfer may deteriorate due to a sudden increase in the wall temperature at a certain condition of a mass and heat flux. In this study, the heat transfer rates in $CO_2$ flowing vertically upward and downward in a circular tube with a diameter of 4.57 mm under various conditions were calculated by measuring the temperature of the outer wall of the tube. The published heat transfer correlations were analyzed by comparing their prediction values with 7,250 experimental data. By introducing a buoyancy parameter, a heat transfer correlation, which could be applied only to a normal heat transfer regime, was extended such that it can be applied to regime of heat transfer deterioration. The published criteria for heat transfer deterioration were evaluated against the conditions obtained from the experiment in this study.

• Horticultural Science & Technology
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• v.34 no.2
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• pp.331-341
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• 2016

We analyzed the functional fragrant components of three species of Cymbidium oriental orchids using gas chromatography-mass spectrometry (GC/MS). For the comparative analysis, C. goeringii 'Minchunran', 'Jugeumhwa', C. forrestii 'Chwigae', 'Songmae', 'Yongja', and C. faberi 'Choemae', 'Namyangmae', 'Hwaja' were investigated. Major fragrant components detected by GC/MS were selected on the basis of more than 3% value according to the analysis of peak area (%). We found that ${\alpha}$-bergamotene, which has a cytotoxic effect on breast cancer, cervical cancer, and glioblastoma, and nerolidol, which induces apoptosis of human hepatoma cells (HepG2), inhibits the growth of Streptococcus mutans and babesiosis, and has antibacterial properties, are common substances produced by C. goeringii L. Nerolidol and ${\beta}$-bisabolene, which is cytotoxic and suppresses the growth of malignant melanoma cells (B16-F10), HepG2, and leukemia cells (HL-60, K562), are major substances in C. forrestii R. Furthermore, ${\alpha}$-pinene, which inhibits the growth of gliobastoma cells (SF-767) and inhibits the anti-inflammatory action of hepatoma cells (BEL-7402); 1,8-cineole, which is a potential therapeutic agent for the treatment of gastric ulcers; and 1,3,7-octatriene, which functions as a pheromone, are the most common substances in C. faveri R. Thus, substances identified as major fragrant components in oriental orchid species have multiple beneficial applications in human health. This research forms the basis for further studies of the roles of major fragrant components in oriental orchids.

• Journal of Food Hygiene and Safety
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• v.28 no.3
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• pp.222-226
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• 2013

A simple and sensitive analytical method was developed using gas chromatograph with electron capture detector (GC-ECD) and gas chromatograph-mass spectrometer (GC-MS) for determination and identification of chloropicrin. Because of small molecular weight and high volatile properties of chloropicrin, analytical method was developed utilizing headspace extraction and direct injection to the GC. The developed method was validated using hulled rice sample spiked with chloropicrin at different concentration levels, 0.1 and 0.5 mg/kg. Average recoveries of chloropicrin (using each concentration three replicates) ranged 77.7~79.3% with relative standard deviations less than 10% and calibration solutions concentration in the range $0.005{\sim}0.5{\mu}g/mL$, and limit of detection (LOD) and limit of quantification (LOQ) were 0.004 and 0.01 mg/kg, respectively. The result showed that developed analytical methods was successfully applied to detect a small amount of chloropicrin in hulled rice.

• The Korean Journal of Food And Nutrition
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• v.28 no.5
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• pp.910-917
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• 2015

Radicchio (Cichorium intybus L.) is widely known to have antioxidant, anti-cancer, and digestion-promoting effects. Antioxidant activity and sensory characteristics of sponge cakes made with radicchio powder were investigated in this study. Sponge cakes were made with freeze-dried radicchio powder added to the flour at concentrations of 1, 3, 5, and 7%. As the amount of radicchio powder increased, the specific gravity of radicchio-containing sponge cakes significantly increased. pH value did not significantly differ between groups. Moisture content decreased from 30.72% (control) to 28.68% (7% radicchio) and loss of mass during baking increased from 7.11% (control) to 9.36% (7% radicchio). L (brightness) and b (yellowness) of sponge cakes decreased while redness increased. Hardness and chewiness decreased as concentration of radicchio powder increased. Springiness and cohesiveness did not significantly differ between any of the groups. Total polyphenol contents ranged from 0.12 to 0.31 mg GAE/g. DPPH scavenging activity significantly increased as the amount of radicchio powder increased. Overall acceptability of sensory experience measured on a 7-point scale was highest in the 3% radicchio cakes (5.35). In conclusion, the addition of 3% radicchio powder improves the sensory qualities of radicchio sponge cakes.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.31 no.6_1
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• pp.483-491
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• 2013

By a development of car navigation systems and mobile or positioning technology, it increases interest in location based services, especially pedestrian navigation systems. Updating of digital maps is important because digital maps are mass data and required to short updating cycle. In this paper, we proposed change detection for different network data-sets based on areal feature matching. Prior to change detection, we defined type of updating between different network data-sets. Next, we transformed road lines into areal features(block) that are surrounded by them and calculated a shape similarity between blocks in different data-sets. Blocks that a shape similarity is more than 0.6 are selected candidate block pairs. Secondly, we detected changed-block pairs by bipartite graph clustering or properties of a concave polygon according to types of updating, and calculated Fr$\acute{e}$chet distance between segments within the block or forming it. At this time, road segments of KAIS map that Fr$\acute{e}$chet distance is more than 50 are extracted as updating road features. As a result of accuracy evaluation, a value of detection rate appears high at 0.965. We could thus identify that a proposed method is able to apply to change detection between different network data-sets.

• Microbiology and Biotechnology Letters
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• v.26 no.4
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• pp.297-302
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• 1998

$\beta$-Xylosidase B was produced by Escherichia coli HB101/pKMG12 carrying the xylB gene of Bacillus stearothermophilus No.236 on its recombinant plasmid. The $\beta$-xylosidase B produced was purified by ammonium sulfate fractionation, DEAE-Sepharose CL-6B, Sephacryl S-200 and Superdex 200 HR gel filtration. The purified enzyme showed the highest activity at pH 6.5 and 5$0^{\circ}C$. But, the enzyme was observed to be very sensitive to the pH and temperature of the reaction mixture. The enzyme was activated about 35% of its original activity in the presence of 1 mM of $Mn^{2+}$ but it was completely inhibited by $Ag^{+}$, $Cu^{2+}$and $Hg^{2+}$ions. In contrast with the $\beta$-xylosidase A, the B enzyme was found to have $\alpha$-arabinofuranosidase activity though the activity was fairly low compared with the $\alpha$-arabinofuranosidase produced from the arfI gene of the same Bacillus stearothermophilus. Therefore, $\beta$-xylosidase B is considered to be more suitable than $\beta$-xylosidase A at least for the biodegradation of arabinoxylan. The $K_{m}$ and V$_{max}$ values of the $\beta$-xylosidase B for o-nitrophenyl-$\alpha$-D-xylopyranoside were 6.43 mM and 1.45 $\mu$mole/min, respectively. Molecular mass of the enzyme was determind to be about 54 kDa by SDS-PAGE and 160 kDa by Superdex 200HR gel filtration, indicating that the functional $\beta$-xylosidase B was composed of three identical subunits.s.