• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09b
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• pp.826-827
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• 2006

Copper infiltration is demonstrated as a viable solution to achieve higher mechanical properties by filling the interconnected porosities of a ferrous structure with copper infiltrant. This paper will present the results of a design of experiments study based on the selected processing variables in the copper infiltration process. The variables are the following: Infiltrating temperatures, infiltrating time at pre-heat zone and hot zone, the green density of iron part, the migration of copper into the iron part at different processing conditions. The results show the flexibility of the infiltration process to attain certain mechanical properties by changing the processing conditions.

• Korean Journal of Animal Reproduction
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• v.25 no.4
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• pp.317-325
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• 2001

This study investigated the effect of ferrous sulfate (Fe$^{2+}$) and/or ascorbic acid (Asc) on fertilizing ability in vitro of frozen-thawed boar spermatozoa. Using chlortetracycline (CTC) fluorescence, the spermatozoa was treated in preincubation medium with control, Fe$^{2+}$(1 mM), Asc (0.5 mM) and Fe$^{2+}$Asc to assessed for acrosome reaction, and the oocyte penetration test to determine whether the Fe$^{2+}$ and/or Asc can promote the penetration ability in vitro. When frozen-thawed spermatozoa was washed with preincubation medium, there were significantly (P ＜ 0.05) more acrosome-reacted in medium with Fe$^{2+}$Asc (38%) than control (27%). The penetration rates were also significantly (P ＜ 0.05) higher in medium with Fe$^{2+}$Asc (76%) than control (55%). Next, the lipid peroxidation of sperm was evaluated on the basis of malondialdehyde production following same treatments. The addition of Fe$^{2+}$Asc to sperm suspension increases the formation of malondialdehyde. However, there were not significantly different under the all conditions. The sperm suspension were also treated with control, Fe$^{2+}$, Asc and Fe$^{2+}$/Asc and assayed for sulfhydry1(-SH) group content. In the Fe$^{2+}$/Asc group, sperm-SH group were higher than another groups. In spermatozoa treated with Fe$^{2+}$ and/or Asc, however, no changes in sperm -SH-groups were detected when compared to controls. In another experiment, the activity of sperm binding to zona pellucida was evaluated through binding to salt-stored porcine oocytes. In control and Asc treatment groups, sperm binding to zona pellucida were significantly (P ＜ 0.05) higher than in medium with Fe$^{2+}$. On the other hand, there is not a significant increase in binding to zona pellucida with spermatozoa treated by Fe$^{2+}$/Asc. In summary, the present study suggests that Fe$^{2+}$/Asc causes an enhancement in fertilizing ability that is associated with penetration rate increased without change of spermatozoa binding capacity to homologous zona pellucida.o homologous zona pellucida.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2003.09a
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• pp.306-309
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• 2003

The natural soil containing organic matter and ferrous is used in the Electrokinetic-Flushing Remediation(EFR) tests. A series of tests are carried out through controlling the concentration of acetic acid in the EFR cell. The test results showed that the electrical potential in X/L=0.9 is increased with the increasing of the concentration, and pH in the sample is the similar at all of the region because of the buffer capacity of natural soil. Finally, the efficiency of EFR is enhanced at acetic acid of 1mM. But it may not be not strongly affected by the concentration of acetic acid.

• Journal of Korean Society of Environmental Engineers
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• v.32 no.1
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• pp.79-86
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• 2010

Effects of operating parameters such as applied voltage, solution conductivity, ferrous ion concentration, electrode material on phenol degradation by pulsed corona discharges were investigated in laboratory scale experiments. The increase of applied voltage enhanced the phenol degradation by generating more energetic electrons. The solution conductivity inversely affected phenol removal rate in the tested ranges because the increase of conductivity decreased the electric field strength through the liquid phase. The addition of ferrous sulfate promoted the phenol degradation through the OH radical production by the Fentonlike reactions between ferrous ion and hydrogen peroxide generated by pulsed corona discharges. Catechol and hydroquinone were detected as primary intermediates of phenol degradation and the decrease of pH and the increase of conductivity were observed probably due to the generation of organic acids. Almost all of the initial phenol was disappeared and 29% of total organic corbon (TOC) was removed in the condition of 0.5 mM of ferrous sulfate after approximately 230 kJ of discharge energy transferred to the reactor.

• Journal of Animal Science and Technology
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• v.47 no.6
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• pp.1025-1032
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• 2005

This study was carried out to separate ovotransferrin in chicken egg white by gel chromatography and heparin affinity chromatography. In gel filtration which was performed with 50mM Phosphate buffer (pH 7.2, 0.15M salt) at a flow rate of 2.0 ml/min, ovotransferrin and ovalbumin were eluted together in fraction number 11-16. In order to separate pure ovotransferrin, fraction No. 12-14 of them which have high concentration of ovotransferrin were concentrated and rechromatographed. However, the ovotransferrin did not separated clearly. In heparin affinity chromatography, the separation was performed with 50mM ethylaminetetraacetic acid (EDTA, pH7.2) and 50mM Phosphate buffer (pH 7.2, 0.15M salt contained) on ferrous and ferric ion saturated column at as same flow rate as gel filtration system's. Ovotransferrin and albumin were eluted together at 10-15min (fraction No.3) and 15-20min (fraction No.4), respectively. However, purified ovotransferrin was eluted at 156-165min and 165-175min (tube No.32-33) with 50 mM phosphate buffer (pH 7.2, 0.15M salt free), respectively. Heparin affinity chromatography with ferric ion saturated column was resulted in the best separation of ovotransferrin rather than separation by gel chromatography and ferrous ion saturated heparin affinity chromatography.

• Environmental Engineering Research
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• v.20 no.2
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• pp.121-125
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• 2015

Biohydrogen production from food waste via dark fermentation was conducted by using mixed culture under various environmental conditions (initial pH, initial F/M ratio, initial ferrous iron ($Fe^{2+}$), and temperature condition) in batch reactor. The results revealed that the maximum hydrogen yield of $46.19mL\;H_2/g\;COD_{add}$ was achieved at the optimal conditions (initial pH 8.0, initial F/M ratio 4.0, initial iron concentration 100 mg $FeSO_4/L$ and thermophilic condition ($55{\pm}1^{\circ}C$)). Furthermore, major volatile fatty acid (VFA) productions of butyrate (765.66 mg/L) and acetate (324.69 mg/L) were detected and COD removal efficiency was detected at 66.00%. Therefore, these optimal conditions could be recommended to operate a system.

• Korean Journal of Environmental Biology
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• v.25 no.4
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• pp.342-348
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• 2007

In a previous study, a new antibacterial activity was found from Paenibacillus polymyxa DY1 isolated from Korean soil, which showed a good growth inhibition against various multidrug resistant enteric bacteria. Thus the effect of nutritional factors and physicochemical conditions on the growth of P. polymyxa DY1 cells and the production of antibacterial activity were evaluated in this study. For the growth of P. polymyxa DY1 cells the optimum condition reaches by incubating at $35^{\circ}C$ for 48 hours by shaking at 180 rpm in the basal medium containing 0.6% dextrose, 1.4% ammonium phosphate dibasic, 0.9% peptone, 2.4% glutamine, and 2 mM sodium molybdate with initial pH 8.0. A maximum level of antibacterial activity was obtained when P. polymyxa DY1 was incubated at $35^{\circ}C$ for 48 hours by shaking at 180 rpm in the basal medium with initial pH 8.0 containing 1% dextrose, 1.5% ammonium sulfate, 1.1% casamino acid, 1.9% aspartic acid, and 2 mM ferrous sulfate.

• Preventive Nutrition and Food Science
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• v.8 no.4
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• pp.406-411
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• 2003

The objective of this study was to investigate the effects of iron supplementation and nutrition education on the iron status and anemia of middle school girls in Ulsan city in Korea. The subjects were already diagnosed as having anemia (hemoglobin < 12 g/dL) or iron deficiency (ferritin < 12 ng/mL and/or transferrin sataturation < 14 %). Over a period of three months, one iron tablet (80 mg Fe as ferrous sulfate/day) was administered to the iron deficient subjects and two tablets (160 mg Fe as ferrous sulfate/day) were administered to the anemia subjects. Total calorie intake of subjects was 82.1 % of RDA. The iron intake of subjects was 91.3 % of RDA and the Ca intake was 78.8 % of RDA. The basal hemoglobin concentration of subjects averaged 12.8 1.2 g/dL, and this increased significantly (p < 0.001) to 13.2 0.9 g/dL after iron supplementation. The basal ferritin concentrations were 14.9 14.2 ng/mL and these significantly increased to 26.6 19.8 ng/mL (p < 0.001). The level of total iron binding protein (TIBC) significantly decreased from the initial 523.1 108.7 $\mu\textrm{g}$/dL to 462.2 90.2 $\mu\textrm{g}$/dL (p < 0.001) after iron supplementation. Anemia symptoms such as‘Being bruised easily’, ‘Inflamed inner mouth’, and ‘Pale face’ improved significantly after iron supplementation in the subjects. There was a negative correlation between their class & year ranking and serum iron level, transferrin saturation after nutritional education and iron supplementation. It was shown, therefore, that the higher the improvement of their anemia level after iron supplementation, the higher their academic performance. It was shown that there was some improvement of their dietary attitudes after nutritional education, and that their serum level related to anemia symptoms and iron nutrition was improved after iron supplementation.

• Journal of Powder Materials
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• v.10 no.6
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• pp.390-394
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• 2003

Ultra fine titanium carbide particles were synthesized by novel metallic thermo-reduction process. The vaporized TiC1$_4$+$CCl_4$ gases were reacted with liquid magnesium and the fine titanium carbide particles were then produced by combining the released titanium and carbon atoms. The vacuum treatment was followed to remove the residual phases of MgC1$_2$ and excess Mg. The stoichiometry, microstructure, fixed and carbon contents and lattice parameter were investigated in titanium carbide powders produced in various reaction parameters.

• Korean Journal of Food Science and Technology
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• v.36 no.3
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• pp.440-447
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• 2004

Characteristics of human ${\beta}-carotene$ 15,15'-dioxygenase isolated by recombinant DNA technology was elucidated. Optimal pH and temperature were 9.0 and $40^{\circ}C$, respectively. Enzyme activity was temperature-sensitive. Enzyme was stable at pH 6.0-9.0 for 24 hr and under $5^{\circ}C$. Half-life of enzyme at $35^{\circ}C$ was 40 min. Crude preparations of enzyme were inhibited by ferrous ion-chelating agent and sulfhydryl-binding agent. GSH offsets inhibitory effect of PCMB. With increasing substrate concentrations, enzyme activity gave typical Michaelis-Menten curve, Based on Hanes-Woolf plot of data, $K_{m}\;and\;V_{max$ were $3.39{\times}10^{6}\;M\;and\;1.2\;pmol/mg$ protein/min, respectively.