• Journal of the Korean Society of Industry Convergence
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• v.16 no.1
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• pp.14-20
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• 2013

In this study, characteristic of new materials for repairing/reinforcement of sea and underwater structures using urethane were studied experimentally. As a results, following their good result was obtained. Materials and construction methods due to a chemical reaction, so no seams, shape or form, regardless of the variety of civil engineering in the field can be applied. Fast workability, hardening existing concrete compared with 80% in shortening. Than the existing large concrete pouring construction cost could be reduced by more than 30%.

• Journal of Powder Materials
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• v.5 no.4
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• pp.241-249
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• 1998

Sintering kinetics of ball-milled $MoSi_2$ was studied with the addition of Ni. $MoSi_2$ powder with the average particle size of 1 $\mu\textrm{m}$ was obtained from ball-milling of 10 $\mu\textrm{m}$ powder. Small amount of Ni was added to the ball-milled $MoSi_2$ powder by salt solution and reduction method. The powder was compacted into cylindrical shape at 200 MPa and isothermally sintered in a $H_2$ atmosphere at the temperature range of 1100~$1400^{\circ}C$ for 3~600 minutes. The changes of linear shrinkage and sintered density were monitored as a function of sintering time. The microstructure was observed by using optical microscopy and scanning electron microscopy. Phases were identified by X-ray diffratometer and electro-probe micro analysis. Sintering kinetics of Ni-added powder was compared to as-milled powder and the apparent activation energy was calculated from Arrhenius plot.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2001.10a
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• pp.51-58
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• 2001

The PTDRT model as prediction techniques of desalinization in reclaimed tidelands was developed and verified in order to be applicable to reclaimed tidelands at the beginning stage. In this model, the changes of salt concentration during desalinization, the water requirements and period required for desalinization, were simulated according to soil properties and desalinization methods by regression analyses. This program was also designed to systematize input data and analysis data associated with desalinization, and to confirm the results by a graphic form. All input data and the results are able to be printed after the form of a typical report.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2003.10a
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• pp.79-82
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• 2003

This study was performed in order to analyze the changes of electrical conductivity during the growing period in Saemangum reclaimed tidal lands soils. According to USDA Salinity Laboratory classification system of salt affected soils, the reclaimed tidal land soils used in this study were saline-sodic soils. As the results obtained from analying the changes of electrical conductivity(EC) during the growing period in reclaimed tidal land soils, EC of irrigation water and soils were no difference among the fertilization quanity, fertilization method and fertilization times.

• Proceedings of the Korea Concrete Institute Conference
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• 2000.10a
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• pp.467-472
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• 2000

It is known that chloride ion in concrete destroys the passive film of reinforcement inside concrete and accelerates corrosion which is the most influencing factor to durability of concrete structures. In this thesis, a chloride ion diffusion model for blast furnace slag(BFS) concrete, which has better resistance to both damage due to salt and chloride ion penetration than ordinary portland cement concrete, is proposed by modifying existing model of normal concrete. Proposed model is verified by comparing diffusion analysis results with both results by indoor chloride penetration test for specimens and field test results for actual RC bridge pier. Also, the optimum resistance condition to chloride penetration is obtained according to degrees of fineness and replacement ratios of BFS concrete. As a result, resistance to chloride ion penetration for BFS concrete is more affected by replacement ratio than degree of fineness.

• Carbon letters
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• v.15 no.3
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• pp.187-191
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• 2014

This study reports on the influence of N-butyl-N-methylpyrrolidinium tetrafluoroborate ($PYR_{14}BF_4$) ionic liquid additive on the conducting and interfacial properties of organic solvent based electrolytes against a carbon electrode. We used the mixture of ethylene carbonate/dimethoxyethane (1:1) as an organic solvent electrolyte and tetraethylammonium tetrafluoroborate ($TEABF_4$) as a common salt. Using the $PYR_{14}BF$ ionic liquid as additive produced higher ionic conductivity in the electrolyte and lower interface resistance between carbon and electrolyte, resulting in improved capacitance. The chemical and electrochemical stability of the electrolyte was measured by ionic conductivity meter and linear sweep voltammetry. The electrochemical analysis between electrolyte and carbon electrode was examined by cyclic voltammetry and electrochemical impedance spectroscopy.

• Journal of Environmental Science International
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• v.13 no.1
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• pp.11-17
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• 2004

The purpose of this study is to present the model of ecological restoration through analysis on the condition of hydrach succession process in brackish water lake. To this study, we investigate and research the present condition of brackish water lake in South Korea. Most brackish water lake in South Korea have characteristics that is come into being malignant hydrach succession. Many lakes were reclaimed to increase foodstuff production. And river conservation work seperate lakes from the ocean. In a embryological view, most lakes based on the brackish water lakes, But present lakes show many different types such as a fresh water lake, a salt lake, a brackish water lake, a swamp, and a marshland. As a result, brackish water lakes have greatly damaged by diverse artificial interventions to promote people's activities. Therefore, in order to manage brackish water lakes systematically, criteria of lake preservation must be coincide with the present conditions of hydrach succession in each lake.

• Clean Technology
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• v.11 no.3
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• pp.153-164
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• 2005

This study found a reliable evaluation for four kinds of pb-Free plating solutions and it's layers, through pure Sn, SnAg, SnBi and SnCu. These four kind of solutions are widely used to pb-Free plating. Hull-cell, Harring-blum, coverage, throwing power, current efficiency, stability, life-time, composition, hardness, roughness, abrasion, scratch, solderability, corrosion, contact angle, morphology, SIR(Surface insulation resistance) and Whisker test were experimented. Also, Using ICP, XRF, FE-SEM, EDS, temperature/humidity chamber, solderability tester, hardness tester, roughness tester, abrasion tester, salt spray tester, contact angle tester, SIR tester, and microscope. In this paper could be shown the systematic and various analysis for reliability about four kinds of pb-Free plating solutions, processes and it's deposit surface.

• Horticultural Science & Technology
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• v.35 no.2
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• pp.243-251
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• 2017

Plants have evolved to adapt to abiotic stresses, such as salt, cold, and drought stress. In this study, we conducted an in-depth analysis of drought resistance mechanisms by constructing a gene co-expression network in Chinese cabbage (Brassica rapa ssp. pekinensis L.). This drought stress co-expression network has 1,560 nodes, 4,731 edges, and 79 connected components. Based on genes that showed significant co-expression in the network, drought tolerance was associated with the induction of reactive oxygen species removal by raffinose family oligosaccharides and inositol metabolism. This network could be a useful tool for predicting the functions of genes involved in drought stress resistance in Chinese cabbage.

• Molecular & Cellular Toxicology
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• v.5 no.3
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• pp.237-242
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• 2009

The potential antioxidant activities of different fractions from methanolic extract of Curcuma longa L. were assayed in vitro. All of the fractions exception of n-hexane and $H_2O$ showed a strong antioxidant activity, especially the ethylacetate (EtOAc) fraction, which showed the highest 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging activity ($IC_{50}=9.86\;{\mu}g/mL$). The results of 2,2'-azinobis (3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) radical scavenging activity and ferric reducing antioxidant power (FRAP) assay showed concentration dependency, the EtOAc fraction demonstrating a better result than the other fractions at the same concentration in this studies. Additionally, when the total phenolic contents of fractions were measured, the EtOAc fraction contained the highest level. Meanwhile, correlation analysis indicated a high correlation between the antiradical activity and the total phenolic contents, suggesting that fractions obtained from the methanolic extract of Curcuma longa L. have wide potential for use as sources of antioxidant material.