• Journal of the Korean Society of Industry Convergence
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• v.16 no.2
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• pp.41-46
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• 2013

On the purpose of helping the inhabitants living in farming, fishing villages, and islands for more safe and hygienic water from simple waterworks, experimental investigations were performed concerning the development of a water purifier with silver nanomaterial packed, having a function of the auto-disinfection. The results show as follows through such filteration and auto-disinfection processes. It is possible to get hygienic and safe water, for example, more than 95% of general bacteria, total coliforms, and fecal coliforms were removed. It is also possible to get good-quality water, for 49.4% of spent potassium permanganate and 85% and 63% of turbidity and conductivity were removed respectively. It is a very effective equipment, for 100% cost reduction of used chemicals was achieved by no-chemical disinfection process and THM was not generated.

• Nuclear Engineering and Technology
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• v.3 no.1
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• pp.9-13
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• 1971

The levels of strontium-90 in milk produced in Korea were determined during the past six years. Milk samples were collected from dairies and market shops in seoul area. Strontium-90 in milk was separated from calcium using fuming nitric acid and purified radiochemically. After seculear equilibrium was completed, the radioactivity of yttrium-90 was counted in a low background beta counting system. The determination of stable calcium in milk was also made by volu-metric method using 0. 1 N potassium permanganate solution. The highest value of 34.9 pCi $^{90}$ Sr/g-Ca was determined in August, 1966 and the lowest value was 7.5 pCi $^{90}$ Sr/g-Ca in August, 1967. From the result we can say that levels of strontium-90 are decreasing year after year and are far bellow the maximum permissible level recommended by International Committe on Radiation Protection.

• Bulletin of the Korean Chemical Society
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• v.30 no.3
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• pp.595-598
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• 2009

The authors describe an analytical method to determine total chlorine in a sanitizer liquid, incorporating a lab-made He-rf-plasma within a PDMS polymer microchip. Helium was used instead of Ar to produce a plasma to achieve efficient Cl excitation. A quartz tube 1 mm i.d. was embedded in the central channel of the polymer microchip to protect it from damage. Rotational temperature of the He-microchip plasma was in the range 1350-3600 K, as estimated from the spectrum of the OH radical. Chlorine was generated in a volatilization reaction vessel containing potassium permanganate in combination of sulfuric acid and then introduced into the polymer microchip plasma (PMP). Atomic emission lines of Cl at 438.2 nm and 837.7 nm were used for analysis; no emission was observed for Ar plasma. The achieved limit of detection was 0.81 ${\mu}g\;mL^{-1}$ (rf powers of 30-70 W), which was sensitive enough to analyze sanitizers that typically contained 100-200 ${\mu}g\;mL^{-1}$ of free chlorine in chlorinated water. This study demonstrates the usefulness of the devised PMP system in the food sciences and related industries.

• Corrosion Science and Technology
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• v.20 no.4
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• pp.175-182
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• 2021

Magnesium alloy is limited in the industrial field because its standard electrode potential is -2.363 V vs. NHE (Normal Hydrogen Electrode) at 25 ℃. This high electrochemical activity causes magnesium to quickly corrode with oxygen in air; chemical conversion coating prevents corrosion but causes surface defects like cracks and pores. We have examined the anti-corrosion effect of sol-gel coating sealed on the defected conversion coating layer. Sol-gel coatings produced higher voltage current and smaller pore than the chemical conversion coating layer. The conversion coating on magnesium alloy AZ31 was prepared using phosphate-permanganate solution. The sol-gel coating was designed using trimethoxymethylsilane (MTMS) and (3-Glycidyloxypropyl) trimethoxysilane (GPTMS) as precursors, and aluminum acetylacetonate as a ring-opening agent. The thermal shock resistance was tested by exposing specimens at 140 ℃ in a convection oven; the results showed changes in the magnesium alloy AZ31 surface, such as oxidization and cracking. Scanning electron microscope (FE-SEM) analysis confirmed a sealed sol-gel coating layer on magnesium alloy AZ31. Electrochemical impedance spectroscopy (EIS) measured the differences in corrosion protection properties by sol-gel and conversion coatings in 0.35 wt% NaCl solution, and the potentiodynamic polarization test and confirmed conversion coating with the sol-gel coating show significantly improved resistance by crack sealing.

• Journal of the Korean Chemical Society
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• v.42 no.2
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• pp.209-213
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• 1998

The higher order structure of Pseudomonas alcaligenes 5S rRNA has been investigated by using ($\eta^{6}$-mesitylene) manganese (Ⅰ) tricarbonyl hexafluorophosphate[MTH-Mn (Ⅰ)], dimethylpyrocarbonate, potassium permanganate as chemical probes. The sequences cleaved strongly by MTH-Mn (Ⅰ) on the tertiary structure of the 5S rRNA are $G_{12}AUGG_{16}$ of loop a, $G_{51}AAGUGAAGC_{60}$ of the region b-C, $U_{65}-AGCG_{69}$. of the region B-a, and $G_{72}AUGG_{76}$ of loop d. Based on such cleavage patterns of 5S rRNA by MTH-Mn(Ⅰ) and other chemical probes, we presume that the sequences strongly cleaved form pocket-like structure as in the the corner of L structure of $tRNA^{Phe}$. We also presume that the region b-C and loop d together play a role of hinge in forming the pocket-like structure in the 5S rRNA.

• Journal of Sericultural and Entomological Science
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• v.32 no.2
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• pp.105-109
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• 1990

The disinfectivity of formalin fumigation was tested against silkworm nuclear polyhedrosis virus and yellow muscardine pathogen, Beauveria bassiana. The inactivation of the virus was acquired when it was fumigated by adding 30g of potassium permanganate to 75$m\ell$ of formalin per 3.3$m^2$ of rearing room area and viability of the yellow muscardine pathogen was also lost with the same treatment of fumigation. It was also proved that the fumigation didn't give and damage to silkworm larvae when it was applied 2 or 3 times to grown larvae.

• Applied Chemistry for Engineering
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• v.5 no.3
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• pp.509-516
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• 1994

Liquid phase hydrogenation come into use for the removal process of unsaturated hydrocarbon such as croton aldehyde. The croton aldehyde is generated in a very small amount as by-product in the ethanol production, and it is converted into n-butanol through hydrogenation. Liquid phase hydrogenation is low energy consumption process as compared with gas phase hydrogenation. The nickel catalyst is selected with respect to the economic aspect such as durability and cost. The analysis of the conversion were performed by method of the PMT(permangante time) test. The PMT was sharply decreased as the initial concentrations of croton aldehyde in the ethanol solution were increased. The hydrogenation of croton aldehyde to n-butanol was carried out in sequence after the saturation of the carbon-carbon double bond. The formation of both butyraldehyde and n-butanol followed zero order kinetics. Within expermental conditions the PMT gets longer as reaction temperature goes higer and as LHSV becomes slower, while the reaction pressure has almost no relation with PMT.

• Journal of Korean Society of Water and Wastewater
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• v.29 no.2
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• pp.211-222
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• 2015

This study focused on evaluating the efficiency of the removal of non-point source pollution by Daecheong Lake Juwon Stream constructed wetlands. The constructed wetland system is a surface flow type designed in the year 2007 for purifying eutrophic water of Daecheong Lake Juwon Stream. The value of conductivity, suspended solids(SS), chemical oxygen demand using a potassium permanganate($COD_{Mn}$), five-day biochemical oxygen demand($BOD_5$), total nitrogen(T-N), total phosphorous(T-P), and pH in inflow averaged 220.2, 2.46, 3.33, 1.34, 2.00, 0.04 mg/L and 7.24, respectively and in outflow averaged 227.9, 1.12, 3.34, 0.87, 1.16, 0.02 mg/L and 7.45, respectively. The average removal efficiency of constructed wetlands was 30 % for SS, 22 % for $BOD_5$, 45 % for T-N and 31 % for T-P. The removal rates of SS, $BOD_5$ and T-N in the spring, summer and autumn were higher than those in winter. The removal rate of T-P was not significant different in all seasons. The amounts of pollutants removal in the constructed wetlands were higher in the order of $3^{rd}$ < $2^{nd}$ < $1^{st}$ wetland for SS and T-P, $2^{nd}$ < $3^{rd}$ < $1^{st}$ wetland for $BOD_5$ and T-N. Therefore, our findings suggest that the constructed wetlands could well treat the eutrophic Daecheong Lake Juwon Stream waters.

• Journal of environmental and Sanitary engineering
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• v.12 no.3
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• pp.19-29
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• 1997

The Chemical Oxygen Demand(COD) by potassium permanganate and potassium dichromate is used as a measure of the organic matter content of a sample. Newly proposed $K_{2}Cr_{2}O_{7}$ analysis method to be list at Korean Official Method was made from analysis and comparison of the experimental process on Japanese Industrial Standard(JIS), American Open Reflux and Closed Reflux Methods. New $K_{2}Cr_{2}O_{7}$ method had better the qualitative and reproducible COD results than another methods as a result of the tested four times repeatedly by using Lakes water Plant wastewater. The COD data ratio by $KMnO_{4}$ and $K_{2}Cr_{2}O_{7}$ methods was 2-3, 3, 2-17 and 3-4 times respectively when its data had compared with the lakes water and treated water of domestic and experimental wastewater, and raw wastewater which is generated at the manufacturing process of 6 steps and treated wastewater of chemistry source. Its ratio indicated to 2-4 and 2-3 times respectively on raw wastewater and plant wastewater of Chemistry, rubber and plastic, fiber, metal molding source. Oxidation ratio of benzene and ethyl benzene by $KMnO_{4}$ method was nearly zero, but the oxidation ratio by $K$_{2}Cr_{2}O_{7}$ method was 50%, 70% respectively. Also, Oxidation ratio of phenol by $KMnO_{4}$ and $K_{2}Cr_{2}O_{7}$ methods was 80%, 100% respectively, and trichloroethylene and tetrachloroethylene were not nearly oxidizd by $KMnO_{4}$ and $K_{2}Cr_{2}O_{7}$ methods. As the above contents, oxidation ratio and COD results by $KMnO_{4}$ and $K_{2}Cr_{2}O_{7}$ were different from various from various compounds and samples respectively.

• Journal of Environmental Impact Assessment
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• v.8 no.1
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• pp.81-92
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• 1999

This study discussed the appropriateness of organic matter indexes such as biochemical oxygen demand(BOD) and chemical oxygen demand with potassium permanganate($COD_{Mn}$) in water quality environmental standard of streams and lakes and the applicability of the items to water quality environmental standard to add or substitute COD with potassium dichromate ($COD_{Cr}$) and total organic carbon(TOC) being used as index of organic matter. And indexes of organic matter content and organic carbon concentration were distinguished between dissolved and particulate component in water sample to estimate their effect on pollutants loading in lake and stream. The ratio of $COD_{Cr}$/BOD was 5.1 under BOD concentration 3mg/L in river water quality environmental standard II, and 2.67 above it. This ratio was diminished to 2.04 when BOD concentration was more than 8mg/L, in river quality environmental standard IV. Also the ratio of $COD_{Mn}$/BOD showed 2.16 under 3mg/L(BOD), and 1.1 above it. This ratio is also diminished to 0.84 over 8mg/L(BOD). Accordingly, we should apply this ratio depending on the concentration level to add and change organic matter index of water quality environmental standard newly. The ratio $COD_{Cr}/COD_{Mn}$ both in lake and stream shows 2.37(r=0.986, p<0.001). But the ratios showed range of 2.34~2.50, which is no much difference of this ratio according to $COD_{Mn}$ concentration.