• Membrane Journal
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• v.28 no.1
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• pp.62-66
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• 2018

In this study the cleaning spherical beads with same density as water were fabricated. Bead moving velocity was measured with respect to the aeration rate and bead concentration in water reservoir. The permeation experiments for FR (filtration and relaxation) and SFCO (sinusoidal filtration continuous operation) modes were simultaneously carried out under the condition of 1 to 3% cleaning spherical bead concentration, 20 LMH and 500 mL/min aeration rate in the MLSS 8,000 mg/L activated sludge solution. The used membrane was the $90cm^2$ effective area and $0.4{\mu}m$ nominal pore size flat membrane. The TMP (transmembrane pressure) decreased as the bead concentration increased, and was shown most effective in FR mode with 2% bead concentration.

• Journal of the Korean Chemical Society
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• v.27 no.5
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• pp.376-381
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• 1983

Dispersed nickel particles on Spherocarb were prepared at 540$^{\circ}C$ in various reaction atmosphere. Magnetic properties of these samples were determined, and results were compared with those of unsupported and MgO supported nickel particles. It was shown that nickel react primarily with carbon regardless of reducing atmosphere. In addition, apparent possibility of nickel-carbon interaction was discussed.

• Transactions of the Korean hydrogen and new energy society
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• v.28 no.3
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• pp.238-245
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• 2017

Mg-Ni nanoparticles were synthesized by a physical vapor condensation method (DC arc-discharge) in a mixture of argon and hydrogen atmosphere, using compressed mixture of micro powders as the raw materials. The crystal phases, morphology, and microstructures of nanoparticles were analyzed by means of X-ray diffraction (XRD) and high-resolution transmission electron microscopy (HRTEM). It was found that the intermetallic compounds of $Mg_2Ni$ and $Mg_2Ni$ formed with existence of phases of Mg, Ni, and MgO in Mg-Ni nanoparticles. After one cycle of hydrogen absorption/desorption process (activation treatment), Mg-Ni nanoparticles exhibited excellent hydrogen absorption properties. $Mg_2Ni$ phase became the main phase by aphase transformation during the hydrogen treatments. The phenomenon of refinement of grain size in the nanoparticle was also observed after the hydrogen absorption/desorption processes, which was attributed to the effect of volume expansion/shrinkage and subsequent break of nanoparticles. Maximum hydrogen absorption contents are 1.75, 2.21 and 2.77 wt.% at 523, 573 and 623 K, respectively.

• Journal of the Korean Society of Visualization
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• v.17 no.3
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• pp.59-65
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• 2019

Phosphor particles ((Sr,Mg)₂ SiO₄:Eu²⁺ were suspended in deionized water in quartz cuvette and used for measuring liquid temperature field by using two-color-ratio method. In the temperature range of 23~77℃, it showed the relative error from 2.4% to 4% and the temperature sensitivity of 0.65 %/℃ at 30℃ and 0.95 %/℃ at 77 ℃. This performance is comparable to measurement techniques using thermographic liquid crystal or laser induced fluorescence or other thermographic phosphor particle. Among investigated potential error sources, the particle number density affected the intensity ratio and the temperature, but the effect of laser fluence was not evident.

• Journal of Animal Environmental Science
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• v.17 no.3
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• pp.197-204
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• 2011

During the process of anaerobic digestion, hydrolysis of substrate is the key factor determining methane production efficiency. The hydrolysis efficiency are directly affected by biodegradability of substrate. In this study, three types of pre-treatment methods were tested to enhance biodegradability effectiveness. By the application of blender and the Cavitation treatment, the SCODcr increased from 24,723 mg/l to 24.726~29,175 mg/l and to 25,589~26,456 mg/l, respectively. In case of ozone treatment, the SCODcr decreased from 24,723 mg/l to 22.540~23,988 mg/l. In batch experiment, there was a little improvement of the biochemical methane potential (BMP) by the blender and the cavitation treatment. In contrast, the BMP somewhat decreased by ozone treatment. This result shows that higher anaerobic digestion efficiency of livestock manure could be obtained through pre-treatment of substrate.

• Journal of Food Hygiene and Safety
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• v.26 no.1
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• pp.43-48
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• 2011

For the application of nano-sized material in various fields, the evaluation of nano-sized material toxicity is important. In the present study, various concentrations of 200 nm-sized silicon dioxide nanoparticle suspension were intraperitonially injected into mice to identify the toxicity of silicon dioxide nanoparticle in vivo. In the hematological analysis of group II treated with silicon dioxide nanoparticle 100 mg/kg body weight, lymphocytes and monocytes were significantly different compared to the control group. In group III treated with silicon dioxide nanoparticle 200 mg/kg body weight, lymphocytes, monocytes and hemoglobin were significantly different compared to the control group. In blood biochemical analysis of group III, the concentration of AST, ALT, BUN, and creatinine were significantly different compared to the control group. Histopathologic examination of the kidney indicated a mild injury only in mice received 200 mg/kg silicon dioxide nanoparticle. According to the results of the present study, the significant differences in the hematological and blood biochemical analyses and abnormal histopathological findings in the mouse kidney may have been related to exposure to silicon dioxide nanoparticle.

• Journal of the Korean Society for Marine Environment & Energy
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• v.12 no.4
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• pp.302-306
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• 2009

9 kinds of nanoparticle used for this study was a particle with the size of less than 100 nm of diameter, and Artemia sp. cyst examined what kind of influence to have upon the process hatched out in nauplius. 82% hatched in nauplius at the opposition ward where a nanoparticle wasn't added after 24 time course. AGZ020, Nano silver, P-25, Sb and SnO nanoparticle showed hatching rate of 18%, 20%, 13%, 50% and 0% respectively by the 20mg/L density, and it became clear that a harmful effect is big, but I had a harmful effect compared with the opposition ward by 75%, 60%, 73% and 73% respectively by Ag-$TiO_2$, In, Sn and Zn nanoparticle, but a feeble thing was known relatively compared with AGZ020, Nano silver, P-25, Sb and SnO nanoparticle. The difference has caused this with the ingredient a nanoparticle has. Ag is included 2 % and AGZ020, Nano silver and P-25 nanoparticle are used widely as anti-fungus agent, and the SnO nanoparticle which became combination is a light catalyst pill, and oxygen is used for a Sn particle. This and others, a possibility that use is generalized and flows into aquatic environment in sequence the home electronics, functionality cosmetics, anti-fungus agent and a light catalyst pill at present becomes high for nanoparticles and others. The anxiety which has an influence on the ecology world in the water with this can be generated, so I'd have to study the potential danger a nanoparticle has continuously.

• Proceedings of KOSOMES biannual meeting
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• 2008.05a
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• pp.137-141
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• 2008

9 kinds of nanoparticle used for this study was a particle with the size of less than 100 nm of diameter, and Artemia sp. cyst examined what kind a influence to have upon the process hatched out in nauplius. 82% hatched in nauplius at the opposition ward where a nanoparticle wasn't added after 24 time course. AGZ020, Nano silver, P-25, Sb and SnO nanoparticle showed hatching rate of 18%, 20%, 13%, 50% and 0% respectively by the 20mg/L density, and it became clear that a harmful effect is big, but I had a harmful effect compared with the opposition ward by 75%, 60%, 73% and 73% respectively by Ag-$TiO_2$, In, Sn and Zn nanoparticle, but a feeble thing was known relatively compared with AGZ020, Nano silver, P-25, Sb and SnO nanoparticle. The difference was mused this with the ingredient a nanoparticle has. Ag is included 2% and AGZ020, Nano silver and P-25 nanoparticle are used widely as anti-fungus agent, and the SnO nanoparticle which became combination is a light catalyst pill, and oxygen is used for a Sn particle. This and others, a possibility that use is generalized and flows into aquatic environment in sequence the home electronics, functionality cosmetics, anti-fungus agent and a light catalyst pill at present becomes high for nanoparticles and others. The anxiety which has an influence on the ecology world in the water with this can be generated, so I'd have to study the potential danger a nanoparticle has continuously.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.7
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• pp.777-784
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• 2005

The first flush phenomenon is defined as the initial period of road runoff during which the concentration of pollutants was significantly high. Road runoff contains significant loads of micro-particles, heavy metals and organic constituents. There were two major objectives of this study. The first objective was to characterize the road runoff. The second objective was to measure and evaluate particle sire distribution of the road runoff, Stormwater runoff was monitored on two sites of four lane road areas along with traffic volume. A total six storm events were monitored to characterize the road runoff. The quantity of road runoff and quality constituents, including chemical oxygen demand ($COD_{Cr}$), suspended solids(SS), total Kjeldahl nitrogen (TKN), ortho-phosphorus ($PO_4-P$), total phosphorus(TP), heavy metals and particle size distribution were analyzed. The results indicate that the concentration of SS, $COD_{Cr}$, TKN and TP ranges were $45{\sim}2,396\;mg/L$, $40{\sim}931\;mg/L$, $0.1{\sim}19.6\;mg/L$, and $0.2{\sim}25.1\;mg/L$, respectively. The results of the regression analysis between SS and the others constituents shows that $COD_{Cr}$, TP, Cu, Pb were highly correlated. And the results showed that the mean range of particle size and uniformity coefficient for road runoff were $6.7{\sim}23.4{\mu}$ and $6.4{\sim}10.2$, respectively.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.2 no.2
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• pp.151-159
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• 1997

Benthic respiration and chemical fluxes were measured at the sediment-water interface underlying the marine fish cages floating on the open coastal waters off Tong-Young, the South Coast of Korea. The effects of cage farming on coastal benthic environment and on mass balance of organic carbon in the benthic boundary layer under the marine fish cages are addressed. In a growing season of caged fishes of June, 1995, benthic chambers and sediment traps were deployed on the sediment-water interfaces of the two sites chosen for this study: 1) Cage Site, directly underlying the fish cages of the farm at 18 m water depth, and 2) Control Site, about 100 m away from the farm at 32 m water depth. Benthic respiration rates and chemical fluxes were calculated from the evolution of dissolved oxygen and chemicals in the chamber water, and mass balance of organic carbon in the benthic boundary layer was constructed based on the vertical flux of particulate organic matter (POM) and chemical fluxes out of the sediment. High organic dumping (6400 mg C $m^{-2}d^{-1}$) and high benthic respiration (230 mmol $O_2\;m^{-2}d^{-1}$) were observed at the Cage Site. Equivalent to 40% of vertical flux of organic carbon into the Cage Site seemed to be decomposed concurrently and released back to overlying waters (2400 mg C $m^{-2}d^{-1}$). Consequently, up to 4000 mg C $m^{-2}d^{-1}$ of organic carbon could be buried into the farm sediment (equivalent to 60% of organic carbon flux into the Cage Site). At the Control Site, relatively less input of organic carbon (4000 mg C $m^{-2}d^{-1}$) and low benthic respiration rate (75 mmol $O_2\;m^{-2}d^{-1}$) were observed despite short distance away from the cages. The influence of cage farming on benthic chemical fluxes might be restricted and concentrated in the sea bottom just below the fish cages in spite of massive organic dumping and high current regime around the fish cage farm.