• 수도
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• s.66
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• pp.5-38
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• 1994

• 제어로봇시스템학회:학술대회논문집
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• 1996.10b
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• pp.640-643
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• 1996

In this paper, a sensitivity of the fiber optic pressure sensor in water is demonstrated. A single mode optical fiber Mach-Zehnder interferometer used to detect the change in optical path length produced by the change of fiber optic strain in water. The sensitivity with this system measured 100.mu.psia through an experiment in the static response.

• Applied Chemistry for Engineering
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• v.27 no.1
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• pp.62-67
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• 2016

In this study, a pellet-type adsorbent was prepared by using the water-treatment sludge as a raw material, and its physical and chemical properties were analyzed through $N_2$-adsorption, XRD, XRF, and $NH_3$-TPD measurements. Adsorption performance for gaseous ammonia and formaldehyde was compared between the pellet-type adsorbents prepared from water-treatment sludge and the impregnated activated carbon. Although the surface area and pore volume of the pellet-type adsorbent produced from water-treatment sludge were much smaller than those of the impregnated activated carbon, the pellet-type adsorbent produced from water-treatment sludge could adsorb ammonia gas even more than that of using the impregnated activated carbon. The pellet-type adsorbent prepared from water-treatment sludge showed a superior adsorption capacity for ammonia which can be explained by chemical adsorption ascribed to the higher amount of acid sites on the pellet-type adsorbent prepared from water-treatment sludge. In the case of formaldehyde adsorption, the impregnated activated carbon was far superior to the adsorbent made from the water-treatment sludge, which can be attributed to the increased surface area of the impregnated activated carbon.

• YAKHAK HOEJI
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• v.24 no.2
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• pp.87-95
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• 1980

Chlorination to polluted water can produce chlorocompounds which may impair human health. It has been discussed that chlorophenols would be one of undesirable substances in drinking water. This study was undertaken to investigate the production mechanism of chlorophenols by chlorination in the disinfection of water and to determine pollution levels of phenols as precursor of chlorophenols and chloropbenols in some sewage, stream water and tap water in the vicinity of Seoul from January to September, 1979. By chlorination with hyperchlorite to phenols in distilled water, o-chlorophenol was predominantly produced at the concentration of less than 10ppm of free chlorine. o-Chlorophenol, 2,6-dichlorophenol and 2,4-dichlorophenol were also produced by chlorination with the concenration from 20 to 100ppm of free chlorine. From the concentration of 100ppm of free chlorine to 200ppm, o-Chlorophenol was vanished and 2,6-dichlorophenol and 2,4-dichlorophenol were determined. Phenols originated from night soil, municipal sewage and stream were determined at 49.15 ppm. 0.095 ppm and 0.003 ppm in average respectively. About 87 and 88 percent of phenols in sewage and night soil were biodegradated by aeration for 10 days and 74 and 51 percent of phenols in sewage and night soil by spontaneous settling for 10 days. From the tap water in Seoul during summer, 1979, chlorophenols were identified; they were average 0.042 ppb of o-chlorophenol, 0.033 ppb of 2, 6-dichlorophenol and 0.003 ppb of 2, 4-dichlorophenol respectively. With the above result and discussion, it is considered that chlorophenols should be controlled from the source as well as chlorination in water purification.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.54 no.5
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• pp.751-760
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• 2021

This study investigated the changes in water quality parameters and microbial colonies when ozone was applied to a semi-recirculating aquaculture system (semi-RAS) for the olive flounder Paralichthys olivaceus (500 g in average weight). Concentrations of ozone-produced oxidants (OPO) in rearing tanks were maintained at 0, 0.014, 0.025 mg/L as Cl₂ for 26 days. Except total ammonia nitrogen, nitrite nitrogen, nitrate nitrogen, phosphate phosphorus, chemical oxygen demand, and total suspended solids decreased significantly with increasing OPO concentration in daily and weekly monitoring (P<0.05). Colony forming unit (CFU) counts of heterotrophic marine bacteria decreased in an OPO concentration-dependent manner. Overall reduction rates of microbial colonies in the treatments were 80% higher than those of the control (P<0.05). During the experiment, the OPO concentration-driven ozonation was reliably practiced without any adverse effects on the animals cultured in semi-RAS. Considering the biohazard, operating cost, and stability of ozonation, an OPO concentration of 0.014 mg/L would be sufficient to control water quality parameters and microbial colonies in a semi-RAS.

• Journal of Korean Society of Water and Wastewater
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• v.24 no.2
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• pp.219-230
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• 2010

Computer simulation has been widely used to design and optimize the operation of wastewater treatment plants since 1980. For secondary clarifiers, the simulation has been a tool to optimize the performance by providing dimensions for flocculation well. However, there has been no attempt to find the optimized geometrical parameters in circular secondary clarifier using simulation tools. In this study, three SVIs (Sludge Volume Indexes), two well types (feed and flocculation wells), 8 SWDs (Side Water Depths) and 9 bottom slopes were variables for simulation. Diurnal inflow and associated MLSS (Mixed Liquor Suspended Solid) concentrations were used for input loadings. When flocculation well was installed, 48% less concentration at lowest ESS (Effluent Suspended Solid) concentrations was produced and the diurnal ESS concentration range had been reduced by 52%. From these results, flocculation well must be installed to produce lower and stable ESS from circular secondary clarifiers. Under same loading conditions with $300m{\ell}$/g of SVI, The lowest ESS was produced when SWD was 4.5m with 4% of bottom slope. Therefore, SWD and bottom slope must not be deeper than 4.5m and must be near 4%, respectively, in circular clarifier with flocculation well to produce the lowest ESS concentration.

• Journal of Ginseng Research
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• v.29 no.2
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• pp.80-85
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• 2005

Antiallergic and antipsoriatic effects of korean Red Ginseng (KRG, steamed root of panax ginseng C.A. Meyer, Family Araliaceae) were measured. Orally administered KRG water extract potently inhibited passive cutaneous anaphylaxis (PCA). KRG water extract also showed the potent inhibition in oxazolone-induced mouse dermatitis, and suppressed mouse ear swelling by $39\%$ at 16 days at a dose of $0.1\%$. KRG water extract reduced the levels of mRNA of cyclooxygenase (COX)-2, $IL-1\beta$, $TNF-\alpha$ and $INF-\gamma$ increased in oxazolone-applied mouse ears, however, did not inhibit that of IL-4. KRG water extract also inhibited iNOS and COX-2 mRNA expression level of RAW264.7 cell induced by lipopolysaccharide. Based on these findings, we suggest that KRG can improve atopic and contact dermatitis by the regulation of $ IL-1\beta$ and $TNF-\alpha$ produced by macrophage cells and $interferon-\gamma$ produced by Th1 cells.

• Journal of Electrochemical Science and Technology
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• v.2 no.2
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• pp.85-90
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• 2011

Active oxygen species or free radicals are considered to cause extensive oxidative damage to biological macromolecules, which brings about a variety of diseases as well as aging. Electrolyzed reduced water(ERW) has been regarded as a ideal antioxidative agent in recent years. ERW is produced by passing a diluted salt solution through an electrolytic cell, within which the anode and cathode are separated by membrane. It can be produced reactive materials in ERW near the cathode during the electrolysis of water. ERW have the following advantages over other traditional cleaning agents: effective antioxidative agent, easy preparation, inexpensive, and environmentally friendly. The main advantage of ERW is its safety and antioxidative effect. ERW with strong reducing potential can be used to remove dirt and grease from items such as cutting boards and other kitchen utensils. The primary aim of this study is the activation mechanism of oxidation reduction potentials, ion conductivity, pH, and electrochemical properties with reactive materials in ERW.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2014.11a
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• pp.173-174
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• 2014

In this research, the effect of the amount of retarder and the washing timing on the quality of aggregate-exposed concrete produced by water-jet washing method is evaluated as a series of test to develop the aggregate-exposed concrete as a concrete finishing method. As a result, the amount of losing aggregate and surface mortar was increased as the dosage of retarder was increased because of the hydration retarding effect of the retarder. Furthermore, as the washing timing was extended, the mortar on the surface of the concrete was not blown by water jet with 8 to 24 ml of retarder because of hydration of cement, hence the surface quality was poor. Therefore, washing timing of one day after concrete placement showed 90 % of aggregate exposed rate and 24 ml of retarder showed the most favorable result of aggregate exposure.

• Journal of KIBIM
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• v.8 no.4
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• pp.72-79
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• 2018

Rapid developments around the world have resulted in urban expansion, habitat destruction, habitat fragmentation, and pollution problems, which are the main reasons for the decline in biological diversity. The United Nations warns that many animals and plants will die out in the near future if this continues. This study was performed to propose a map of eco-corridor suitability analysis of Korean water deer(Hydropotes Inermis) to enhance biodiversity in Chuncheon city. Eight factors affecting habitat suitability were elevation, aspect, slope, forest type, distance to the road, distance to the stream, land use and green connectivity. Previous study analysis on the mobility behaviour of the Korean water deer(Hydropotes Inermis) produced a habitat suitability map by determining the threshold and assigning a value between 0 and 1 depending on the habitat suitability using the fuzzy function. A method of analysis was proposed for a number of eco-corridor through comparative analysis of the data from the produced habitat suitability map and the road-kill point. The previous studies were focused on Backdudaegan region and national parks except for urban cities. The potential habitat map of Korean water deer could be helpful as a way to prevent habitat disconnection and increase species diversity in urban areas.