• Journal of Food Hygiene and Safety
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• v.3 no.4
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• pp.211-215
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• 1988

Anion chromatographic (lC) method was developed for the determination of sulfites infoods. Sulfites refer to sulfur dioxide that was separated from a food sample by addition of acid and heating, and carried into a trapping solution by distillation. The trapping solution was applied to IC system. Sulfites was separated on an anionic separator column, HPIC-AS4A with 0.75mM $NAHCO_3/2.25mM\;Na_2CO_3$ as the eluent and determined by the use of conductivity detector. The recoveries of sulfites added to water, carrot and apple at level of 1 ppm were 99.8%, 91.6% and 83.5%, respectively. The detection limit was 0.2 ppm in the case of a 10 g sample size. All experiment could be finished within 20 minutes

• Nuclear Engineering and Technology
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• v.54 no.8
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• pp.3051-3058
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• 2022

In the present work, untreated Iraqi sand with grain sizes varied between 100 and 200 ㎛ was used to produce a colored glass sample that has shielding features against the low gamma-ray energy. Therefore, a weight of 70-60 wt % sand was mixed with 9-14 wt% B₂O₃, 8-10 wt% Na₂O, 4-6 wt% of CaO, 3-6 wt% Al₂O₃, in addition to 0.3% of Co₂O₃. After melting and annealing the glass sample, the X-ray diffraction spectrometry was applied to affirm the amorphous phase of the fabricated glass samples. Moreover, the X-ray dispersive energy spectrometry was used to measure the chemical composition, and the MH-300A densimeter was applied to measure the fabricated sample's density. The Makishima-Makinzie model was applied to predict the mechanical properties of the fabricated glass. Besides, the Monte Carlo simulation was used to estimate the fabricated glass sample's radiation shielding capacity in the low-energy region between 22.1 and 160.6 keV. Therefore, the simulated linear attenuation coefficient changed between 10.725 and 0.484 cm^-1, raising the gamma-ray energy between 22.1 and 160.6 keV. Also, other shielding parameters such as a half-value layer, pure lead equivalent thickness, and buildup factors were calculated.

• Microbiology and Biotechnology Letters
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• v.9 no.3
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• pp.145-152
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• 1981

Microorganisms from the waste water of starch industry, were isolated and a strain, Y-124, possessing a powerful enzymic activity was selected and identified as a member of the genus Bacillus. The ideal cultural condition for the formation of $\alpha$-amylase form Bacillus Y-124 and its preservation was investigated in connection with the biotechnological and industrial approach to the bulk enzyme production. High yield of $\alpha$-amylase was observed in medium containing casein as well as calcium pantothenate in this work. Calcium ions were found to have an effect in forming this particular enzyme. Ammonium phosphate dibasic was an important inorganic nitrogen source for the formation of $\alpha$-amylase. And preservation of this enzyme was greatly affected by calcium or sodium salts. The addition of calcium carbonate or sodium sulfate presented the most effective result for the prevention of its denaturation to various factors. The above data was obtained with crude enzyme preparation.

• Proceedings of the Korean Geotechical Society Conference
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• 2008.10a
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• pp.1475-1486
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• 2008

Bentonite-based grouting has been popularly used to seal a borehole installed for a closed-loop vertical ground heat exchanger in a geothermal heat pump system (GHP) because its high swelling potential. However, if the bentonite-based grouting is conducted in coastal areas, the salinity of groundwater changes in the mineral fabric of bentontie. In order words, an increase of cation concentration in groundwater leads to a reduction in the diffuse double-layer thickness in the bentonite mineral structure, and thus the volume of bentointe-based grouts will decrease proportional to the salinity of groundwater. In this paper, the effect of salinity (i.e., NaCl 0.5M, 0.25M, and 0.1M) on the change of swelling potential for bentonite-based grouts has been quantitatively evaluated for seven bentonite grouts from different product sources. In addition, in case of using addictives such as a silica sand to increase the thermal conductivity of bentonite-based grouts, the possibility of particle segregation has been studied considering the viscosity of grouts and salinity of groundwater.

• Wind and Structures
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• v.13 no.6
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• pp.529-556
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• 2010

This paper investigates the correlation of wind characteristics monitored on a cable-stayed bridge. Total five anemoscopes are implemented into the bridge. Two out of 5 anemoscopes in inflow and two out of 5 anemoscopes in wake-flow along the longitudinal direction of the bridge are installed. Four anemoscopes are respectively distributed at two cross-sections. Another anemoscope is installed at the top of the tower. The correlation of mean wind speed and direction, power spectral density, the turbulent intensity and integral length of wind in flow at two cross-sections are investigated. In addition, considering the non-stationary characteristics of wind, the spatial correlation in time-frequency is analyzed using wavelet transform and different phenomenon from those obtained through FFT is observed. The time-frequency analysis further indicates that intermittence, coherence structures and self-similar structures are distinctly observed from fluctuant wind. The flow characteristics around the bridge deck at two positions are also investigated using the field measurement. The results indicate that the mean wind speed decrease when the flow passing through the deck, but the turbulence intensity become much larger and the turbulence integral lengths become much smaller compared with those of inflow. The relationship of RMS (root mean square) of wake-flow and the mean wind speed of inflow is approximately linear. The special structures of wake-flow in time-frequency domain are also analyzed using wavelet transform, which aids to reveal the forming process of wake-flow.

• Journal of the Korean Ceramic Society
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• v.44 no.5 s.300
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• pp.155-159
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• 2007

Blue light-emitting phosphors having the excitation spectrum range of the medium-long ultraviolet ($280nm{\sim}400nm$) have been prepared by solid state reaction method. As a starting material the natural alkaline feldspar powder produced from the domestic mine field in Buyeo, Chungnam-do. The photoluminescence characteristics and crystal structures have been analyzed for the phosphor samples. The powder mixture of the natural alkaline feldspar and the rare-earth oxide was calcined at $800{\sim}1000^{\circ}C\;for\;3{\sim}4h$ in air. The calcined samples we fully ground at room temperature and then heat-treated in the mild reducing gas atmosphere of $5%H_2-95%N_2$ mixture at $1100{\sim}1150^{\circ}C\;for\;3{\sim}4h$. The natural alkaline feldspar material consists of the monoclinic orthoclase ($KAlSi_3O_8$) and the triclinic albite ($NaAlSi_3O_8$) phases. At the $0.5wt%Eu_2O_3$ addition the PL spectrum showed the maximum intensity and with further increase of $Eu_2O_3$ the PL intensity decreased. The albite phase disappeared in the $Eu_2O_3$ doped phosphors. The effect of the co-doped activator on the PL characteristics have been also discussed.

• Korean Journal of Plant Resources
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• v.34 no.3
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• pp.203-215
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• 2021

Bok choy is one of Brassica vegetables widely consumed worldwide. Brassica vegetables have been reported to exert various pharmacological activities such as antioxidant, anti-cancer and cardioprotective activity. However, studies on immunostimulatory activity of bok choy sprout have not been conducted properly. Thus, in this study, we investigated in vitro immunostimulatory activity of bok choy sprout extract (BCS) using mouse macrophage RAW264.7 cells. Our results showed that BCS increased the production of immunomodulators such as NO, iNOS, IL-1β, IL-6, IL-12, TNF-α and MCP-1, and phagocytic activity in RAW264.7 cells. BCS activated MAPK, NF-κB and PI3K/AKT signaling pathways. However, BCS-mediated production of immunomodulators was dependent on JNK, NF-κB and PI3K/AKT signaling pathways. the mRNA expression of TLR2 were significantly increased by BCS, TLR2 inhibition by anti-TLR2 dramatically suppressed the production of immunomodulators by BCS. In addition, TLR2 inhibition by anti-TLR2 significantly reduced BCS-mediated phosphorylation level of AKT, JNK and NF-κB. From these results, BCS may have immunostimulatory activity via TLR2-MAPK, NF-κB and PI3K/AKT signaling pathways. Therefore, BCS expected to be used as a potential immune-enhancing agent.

• Journal of Korean Society of Water and Wastewater
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• v.32 no.3
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• pp.211-220
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• 2018

The water containing soluble manganese may cause problems such as discolored water, unpleasant taste, fouling or scaling of pipes in water distribution system, and so on. Conventional water treatment processes using sand filtration or sedimentation after oxidation, however, cannot often meet manganese standard for drinking water. Two types of oxidants, potassium permanganate ($KMnO_4$) and sodium hypochlorite (NaOCl), were utilized at the same time for manganese oxidation, and then the precipitated manganese oxides were removed by low pressure membrane filtration in this study. In batch experiments, the multiple injection of both oxidants showed more effective manganese removal than did the single injection using either of them. Moreover, the deterioration of manganese removal at low temperature was less serious for the multiple injection than that for the single injection. Manganese removal by the continuous system of oxidation by multiple injection combined with membrane filtration was higher than those by batch experiments at the same oxidation conditions. In addition, less membrane fouling was observed for membrane filtration with oxidation during continuous membrane filtration than membrane filtration without oxidation. These results indicate that the oxidation by multiple injection coupled with membrane filtration was efficient and applicable to actual water treatment for manganese removal.

• Journal of Korean Society of Environmental Engineers
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• v.35 no.3
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• pp.226-232
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• 2013

Several pretreatment processes such as softening, coagulation and precipitation, activated carbon adsorption, ion-exchange and neutralization processes were studied to remove organics and inorganics for selection of the RO based reusing system of metal industry wastewater. The effects of the hydrophobic/hydrophilic fractions of the organics on DOC removal were tested and used to optimize the combination process. Among various pretreatment processes, softening could reduce 93.4% of hardness and could remove all hydrophobic organics from the effluent of metal industry wastewater. Softening followed by coagulation process could reduce DOC (Dissolved Organic Carbon) from 5.1 mg/L to 1.6 mg/L. In addition, as a result of physiochemical pretreatment to raw wastewater of metal industry, neutralization with NaOH showed an efficient removal of iron and TDS (Total Dissolved Solids) without increase in the hardness.

• Microbiology and Biotechnology Letters
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• v.17 no.3
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• pp.207-212
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• 1989

Cultural conditions for $\alpha$-D-Glucosidase Inhibitor production from Streptomyces sp. YS-221-B isolated from soil arid identified as Streptomyces flauovirens or a subspecies of it were investigated. When the strain was cultured in a flask containing 2% glucose, 0.3% asparagine, 0.0002% riboflavin, 0.05% $K_2$HPO$_4$, 0.1% MgSO$_4$.7$H_2O$, 0.05% NaCl, pH 8.0 at 3$0^{\circ}C$, maximum production of the inhibitor was obtained after 8-9 days of cultivation. Sugar alcohols such as mannitol, i-inositol, erythritol as carbon sources, asparagine and beef extract as nitrogen sources were favorable for inhibitor production. Among vitamins, riboflavin, p-aminobenzoic acid, pyridoxamine and folic acid promoted the production of inhibitor, but depressed by the addition of hesperidine, and also depressed by cobalt, lithium and ferrous salts.