• International Journal of Naval Architecture and Ocean Engineering
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• v.10 no.1
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• pp.85-94
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• 2018

For the design of wind-power facilities, the highest and lowest astronomical tides (HAT and LAT, respectively) are needed for the tidal-water levels regarding international designs; however, the approximate highest high water and approximate lowest low water AHHW and ALLW, respectively, have been used in Korea. The HAT and LAT in the wind-farm test-bed sea should be estimated to satisfy the international standard. In this study, the HAT and LAT are therefore estimated using the hourly tidal-elevation data of the Eocheongdo, Anmado, Younggwang, Gunsan, Janghang, and Seocheon tidal-gauging stations that are located in the adjacent coastal sea. The nodal variation patterns of the major lunar components, such as $M_2$, $O_1$, and $K_1$ are analyzed to check the expected long-term lunar cycle, i.e., 18.61 year's nodal-variation patterns. The temporal amplitude variations of the $M_2$, $O_1$, and $K_1$ clearly show the 18.61-years periodic patterns in the case of the no-nodal correction condition. In addition, the suggested HAT and LAT elevations, estimated as the upper and lower confidence limits of the yearly HAT and LAT elevations, are 50 cm greater than the AHHW and 40 cm lower than the ALLW, respectively.

• Journal of Sensor Science and Technology
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• v.9 no.3
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• pp.153-162
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• 2000

Triple points of high purity materials have been used to calibrate primarily the capsule-type platinum resistance thermometer (PRT) in the temperature range of the triple point of equilibrium hydrogen (13.8033 K) and water (273.16 K). In this work, triple points of Ne, $O_2$, Ar, Hg and $H_2O$ except for the triple point of equilibrium hydrogen were realized to establish the International Temperature Scale of 1990 (ITS-90). At each fixed point, two capsule-type PRTs, which were selected for the international comparison, were tested two times. The combined uncertainties of the realization of each triple point were calculated considering the type A and type B evaluation. In Korea Research Institute of Standards and Science, the combined standard uncertainties of the defining triple Points by the ITS-90 were estimated to about 0.18 mK for Ne, 0.14 mK for $O_2$, 0.14 mK for Ar, 0.24 mK for Hg and 0.11 mK for $H_2O$, respectively.

• International Journal of Highway Engineering
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• v.18 no.1
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• pp.43-55
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• 2016

PURPOSES : This study aims to develop a repair material that can enhance pavement performance, inducing rapid traffic opening through early strength development and fast setting time by utilizing MgO-based patching materials for repairing road pavements. METHODS : To consider the applicability of MgO-based patching materials for repairing domestic road pavements, first, strength development and setting time of the materials were evaluated, based on MgO to $KH_2PO_4$ ratio, water to binder ratio, and addition ratio of retarder (Borax), by which the optimal mixture ratio of the developed material was obtained. To validate the performance of the developed material as a repair material, the strength(compressive strength and bonding strength) and durability (freezing, thawing, and chloride ion penetration resistance) was checked through testing, and its applicability was evaluated. RESULTS : The results showed that when an MgO-based patching material was used, the condensation time was reduced by 80%, and the compressive strength was enhanced by approximately 300%, as compared to existing cement-based repair materials. In addition, it was observed that the strength (compressive strength and bonding strength) and durability (freezing and thawing, and chloride ion penetration resistance) showed an excellent performance that satisfied the regulations. CONCLUSIONS : The results imply that an emergent repair/restoration could be covered by a rapid-hardening cement to meet the traffic limitation (i.e. the traffic restriction is only several hours for repair treatment). Furthermore, MgO-based patching materials can improve bonding strength and durability compared to existing repair materials.

• Journal of People, Plants, and Environment
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• v.24 no.1
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• pp.53-62
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• 2021

Background and objective: Dermatitis is a chronic disease accompanied by such symptoms as itching and dry skin. The environment and diet can aggravate dermatitis, so attention to skin care is essential. Colocasia esculenta is used in various manners and for different purposes, including with regard to inflammation, aging, and the digestive system. The anti-inflammatory effect of Colocasia esculenta water extract was confirmed using RAW 264.7 macrophages with regard to male ICR mice. Methods: In the case of the ICR mice, 5% 12-O-Tetradecanoylphorbol-13-acetate (TPA) was used to cause inflammation for 7 days, and 100 μL of Colocasia esculenta water extract and panthenol were administered orally for 10 days. In addition, RT-PCR, NO, ELISA was conducted. Results: As a result of reverse transcription polymerase chain reaction (RT-PCR) using RAW 264.7 macrophages stimulated with lipopolysaccharide (LPS), it was found that Colocasia esculenta water extract reduced the expression of inflammatory cytokines. As a result of hematoxylin and eosin (H&E) staining using mouse ear tissue, Colocasia esculenta water extract reduced ear thickness and showed an effect of suppressing ear edema. In addition, compared to the TPA-treated group, the Colocasia esculenta extract-treated group had reduced nitric oxide (NO) production by 18.23 μM and IL-13 production decreased by 136.55 pg/ml. Conclusion: Colocasia esculenta water extract has been shown to be effective in lowering inflammatory cytokine production. These results suggest that Colocasia esculenta water extracts can be used as natural products to treat dermatitis.

• Journal of the Korean Society for Precision Engineering
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• v.18 no.11
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• pp.168-173
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• 2001

The chemical mechanical polishing (CMP) is generally consisted of pad, slurry including abrasives and so on. However, there are some problems in a general CMP: defects, a high Cost of Consumable (CoC), an environmental problem. The slurry including abrasives especially gives rise to not only increase a CoC, but also prohibition from achieving an eco-process. This paper introduces an abrasive capsulation pad to achieve an eco-process decreasing abrasives used is CMP. The binder wth a water a water swelling and a water soluble characteristic is used for an auto-conditioning, and the $CeO_2$abrasive is selected for an abrasive capsulation pad. Comparing with a conventional CMP, an abrasive capsulation pad appears good characteristics in ILD CMP and is able to achieve an eco-process decreasing wasted slurry.

• Journal of Korean Society of Environmental Engineers
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• v.37 no.5
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• pp.262-268
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• 2015

This study established an analytical method to simultaneously determine six organophosphorous pesticides [methyldemetone-S, diazinon, fenitrothion, parathion, phentoate, and O-ethyl O-(4-nitrophenyl) phenylphosphonothioate (EPN)] and carbaryl in water using a gas chromatography/mass spectrometry (GC/MS) system coupled with on-line micro extraction by packed sorbent (MEPS) and programmed temperature vaporizer (PTV) injector. Polystyrene divinylbenzene (PDVB) was used as a sorbent of MEPS. The effects of elution solvents, pH, elution volume and draw-eject cycles of samples on sample pretreatment process were investigated. Also, quality assurance and quality control (QA/QC) and the recovery of the pesticides in environmental samples were evaluated. The elution was performed using $30{\mu}L$ of a mixed solvent (acetone : dichloromethane = 80 : 20 (v/v)). Sample pretreatment processes were optimized with seven cycles of draw-eject of sample (1 mL) spiking an internal standard and sulfuric acid. At lower pH, the analytical sensitivity of diazinon decreased, but that of carbaryl increased. The method detection limit and the limit of quantification for this method were 0.02~0.18 and $0.08{\sim}0.59{\mu}g/L$, respectively. The method precision and accuracy were 1.5~11.5% and 83.3~129.8%, respectively, at concentrations of $0.5{\sim}5.0{\mu}g/L$. The recovery rates for all the pesticides except carbaryl in various environmental samples ranged 75.7~129.3%. The recovery rate of carbaryl in effluent sample was over 200% whereas carbaryl in drinking water, groundwater, and river water were in the acceptable range.

• Korean Journal of Ecology and Environment
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• v.38 no.3 s.113
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• pp.382-392
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• 2005

Data were collected in Lake Daecheong from March 1997 to October 2002 and used to understand an annual change of water environmental factors and trophic states. The surface water temperature was ranged from $3.2^{\circ}C$ to $33.1^{\circ}C$ In the middle of February, water temperature was the lowest. Turbidity was ranged from 0.1 to 203.5 NTU, but the values of above 30 NTU were only measured at site 1. The total mean values of COD and Chl a were $3.6{\pm}1.4\;mg\;O_2\;L^{-1}$, $9.3{\pm}12.8\;{\mu}g\;L^{-1}$respectively. The concentrations of TP and TN were ranged from 0.14 to 5.09 mg N $L^{-1}$, 1 to $247\;{\mu}g\;P\;L^{-1}$ respectively. The total mean value of TN/TP ratio was $98.7{\pm}56.2$. The trophic states were ranged from mesotrophic to eutrophic in Lake Daecheong.

• Journal of the Korea Institute of Building Construction
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• v.18 no.4
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• pp.321-327
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• 2018

Blast furnace slag has been actively used as a substitute for cement in the construction field with high value-added through resource recycling research. However, most of the slag cannot find a clear recycling purpose. This is because some slags contain unstable materials and are used for road-use asphalt and embankment, which are low value-added materials. Electric arc furnace reduction slag(ERS) has been reported to contain a large amount of unstable free CaO due to deoxidation and component adjustment. In this study, free CaO of ERS which is generated in Korean steelmakers is quantitatively evaluated by using ethylene glycol method. As a result of free CaO quantitative evaluation of ERS, it was confirmed that there is a big difference according to the location of each field. In addition, ERS generally existed in powder form as undifferentiated characteristics, but it was confirmed that free CaO content was different due to hydration product in aggregate form due to water treatment. In addition, free CaO is an amorphous material and its crystallization characteristics are different due to the influence of temperature when it is cooled. ERS requires a long-term aging period as it contains a lot of free CaO.

• 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.