• Korean Journal of Environmental Agriculture
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• v.28 no.3
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• pp.289-294
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• 2009

Concerning about the negative impact of chemical pesticides on human health and the environment has been leading to dramatic increase of research in natural product-based pesticides. An antagonistic bacterium Streptomyces sp. S-1110 was isolated from apple farm soil. The culture filtrate of the strain showed growth inhibition effects to apple pathogenic fungi, Botryosphaeria dothidea, Colletotrichum gloeosporioides and Rhizoctonia solani. The unidentified antibiotic substances from the strain kept antagonistic activity either after heat treatment at $121^{\circ}C$ for 1 h or pH treatment at range of pH 3 - pH 12 for 24 h. The substances also prevented apple fruit from spoiling by inoculated two pathogenic molds, B. dothidea and C. gloeosporioides. These results suggested that the isolated strain would be useful as a biocontrol agent to control apple spoiling occurred from mold.

• Resources Recycling
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• v.20 no.2
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• pp.67-73
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• 2011

In this study, for recovery of renewable noble metal from used stack of fuel cell, synthesis of platinum nano particle is established through effect of platinum solution concentration, pH value, reducing agent and dispersing agent at a volume ratio of 1 mM $H_2PtCl_6$:10 mM $NaBH_4$:8 mM Cl4TABr = 1:0.4:0.4(vol.%), pH4, $50^{\circ}C$, 160 rpm and 10min. Less than 5 nm platinum particles were synthesized using Pt leaching solution from used MEA of stack under same condition of method using simulated Pt solution. The characteristics of synthesized nano particles was illustrated by XPS analysis as the reduction of platinum ions into platinum metals(zero-valent).

• Bulletin of the Korean Chemical Society
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• v.27 no.9
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• pp.1341-1345
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• 2006

An electrostatic interaction is responsible for the attachment of gold seeds of 1-3 nm onto APTMS (3-aminopropyl trimethoxysilane)-coated silica cores in the formation of gold clusters. A surface plasmon resonance and morphology of gold clusters were significantly affected by the pH of gold colloids prepared by THPC reducing agent. Gold colloids of alkaline pH induced the heterogeneous deposition of gold seeds onto the silica nanoparticles, probably due to the continuous reduction of residual gold ions during the attachment process. Gold colloids of acidic pH induced the monodisperse deposition of gold seeds, consequently leading to the formation of smooth gold layer on the silica nanoparticles surface. The gold nanoshells (core radius = 80 nm) prepared by gold colloids of pH 3.1 exhibited the more red-shift and relatively stronger intensity of plasmon absorption bands, compared with gold nanoshells prepared by alkaline gold colloids of pH 9.7.

• Journal of Korean Society of Water and Wastewater
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• v.9 no.3
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• pp.108-115
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• 1995

The feasibility study of using converter slag as a solidifying agent of digested sewage sludge cake has been performed. The availability of converter slag as solidifying agent has been investigated by several trial tests. Based on the trial test results, the optimum mixing ratios of sludge cake and solidification additive are estabilished. Finally the solidification characters of sludge cake are elucidated by SEM and EDS. It is ascertained that converter slag with a small amount of quicklime enhences the solidification. From the result of pH test, overall pH of specimens tends to decrease slowly with curing time. After solidifying specimens had been cured for 7 days, these are water-cured for 24 hours. The weight and strength of all the specimens are nearly the same regardless of the mixed ratios of solidifying agent. The result of leaching tests for four heavy metal ions, Cd, $Cr^{6+}$, Pb and Cu show that the leaching strength becomes below the decision criteria of the specific wastes, respectively. The SEM observation of the delicate structure shows that needlelike crystals appear after solidification which are not observed before. From the EDS analysis, it is found that the main ingredients of needlelike crystals are Ca, Si, Al and O.

• Journal of Korean Society on Water Environment
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• v.24 no.4
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• pp.415-422
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• 2008

Drinking water treatment is enhanced by coagulant dosages and chlorine injection because of pH increase in raw water in droughty seasons such as spring and fall. But water quality deterioration is occurred by increase in residual aluminium and disinfection by-products. Coagulation process can be used to control natural organic matter (NOM) during water treatment. The effect of coagulation process appeared to depend on the pH of water rather than coagulant dosages. In this study, for water treatment in high pH season $H_2SO_4$ was applied for pH adjustment at full scale. Before and after pH adjustment by $H_2SO_4$ injection, water quality of drinking water was evaluate. In the result of investigation of total organic carbon (TOC) removal in high pH season, TOC was removed approximately 30~40%, which showed decrease in water treatment efficiency. Also, it is increased both particle numbers and residual Al concentration in the water. After $H_2SO_4$ injection for adjustment to pH<7.5 in settled water, treated water turbidity decreased in 0.047 NTU from 0.059 NTU, and particle numbers of filtered water decreased in 20/mL from 90/mL. On the other side, TOC removal efficiency increased in approximately 10% after adjustment of pH. In the result of decrease in pH in raw water through more coagulants and prechlorine without $H_2SO_4$ injection, trihalomethanes (THMs) concentration increased in $16{\mu}g/L$ from $8{\mu}g/L$.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2018.11a
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• pp.555-556
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• 2018

• Proceedings of the Korean Institute of Building Construction Conference
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• 2002.11a
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• pp.7-10
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• 2002

Concrete used up to date semipermanent architecture material but now day concrete early deterioration emboss social issue because of construction structure and environmental factor. so, many study of deterioration concrete construction improve durability used impregnation alkalization agent. In These to Study of derelop reoairmeat material in reduce carbonation. xoncrete Building use Alkalinity Recovery Agent which is Realkalinity and strength surface. Alkalinity Recovery Agent undisposed application volume and cure the concrete period. To study Alkalinity Recovery Ahent spray and cure the concrete propriery in field.

• Microbiology and Biotechnology Letters
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• v.51 no.4
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• pp.425-431
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• 2023

The biopolymer produced by Lysinibacillus macroides can be useful as an emulsifying agent, flocculating agent, anti-oxidative agent, and anti-corrosive agent. The present work focused on the functional activities of this biopolymer such as bioflocculant and anti-corrosion. The results of the study for the biopolymer as a bioflocculating agent reveal that the biopolymer gave 72.3% flocculating activity against activated carbon at a concentration of 5 mg/l. In the optimization study, the highest bioflocculant activity was obtained in the presence of CaCl₂ mineral at 15% biopolymer concentration, 7.0 pH, and 40℃ temperature. The biopolymer was also studied for its anti-corrosive nature and observed that it was able to prevent corrosion of steel paper clips in a 6% CaCl₂ solution at a concentration of 0.5% after 7 days.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.8
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• pp.3112-3118
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• 2010

The pH control agent in PWRs, to insure the integrity of steam generator, was changed from ammonia to ethanolamine(ETA) which decreased pH at condensate system and low pressure feedwater heater drain system, so that several amines were investigated for the selection of the optimum amine. There was no single alternative amine to meet the optimum condition. The more volatile ammonia provides the higher pH in condensate, while the less volatile ETA increases the pH in wet steam area. Thus, the combined amine of ammonia and ETA is able to equally raise the pH in both region so that the flow accelerated corrosion be reduced in the every system of the secondary side and the integrity of steam generator be also improved in pressurized water reactors (PWRs).

• Journal of the Korean institute of surface engineering
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• v.36 no.3
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• pp.263-271
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• 2003

Optimal conditions of electroless nickel plating in acid baths has been studied for industrial applications of a developed EN solution. The phosphorus content in the deposition ranges from 8 to $12\;wt.\%$. The investigated EN plating parameters are ion concentrations of nickel and hypophosphite, concentration of reducing and complexing agent, temperature, and pH. The average plating rate of Ni-P deposition was ca. $14{\mu}m/h$. The EN solution used shows a deposition rate of $10{\mu}m/h$ up to seven metal turnovers.