• Journal of Ocean Engineering and Technology
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• v.21 no.3 s.76
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• pp.58-64
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• 2007

New artificial fishing reefs are developed using modified sulfur concrete. Modified sulfur concrete, which is made of by-product aggregates and modified sulfur binder, has good properties, including high density, less water absorption, high strength, high salt resistance, and good affinity for living organisms. This paper shows the mechanical properties of modified sulfur concrete and its field tests under the sea. We have found that the pH-neutral materials attach microalgae and seaweed more readily, compared to the pH-high materials.

• Proceedings of the Korea Concrete Institute Conference
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• 1998.10c
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• pp.211-216
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• 1998

Recently the shortage of good aggregate has encouraged the use of sea sand in construction field, and the corrosion damage of the reinforced steel in concrete structures has been increased due to chlorides from sea sand and deicing salt. Therefore, a number of researchs are proceeding to prevent the corrosion of the reinforced steel in concrete, especially in marine environments. This study focused on the effect of corrosion inhibitors to evaluate protection characteristics for mortar specimens containing clorides. Corrosion behaviors have been investigated by half-cell potential measurement, linear polarization method, AC impedance method, and cyclic polarization test after immersing in sea water for 7 years. A possitive effect of a corrosion inhibitor has been obtained.

• 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 the Korean Society for Railway
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• v.5 no.1
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• pp.32-39
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• 2002

As most railways are gradually electrified with modernized electric cars, the demand for catenary wires and their facilities are also increased. Catenary Wires are exposed to the marine area with air-borne salt or severely polluted industrial area with much corrosive emission gases depending on the locations. Corrosion of catenaty wires can make their actual lifetime shorter than that originally designed. Thus, the messenger and ACSR wires, kinds of catenary wire system, were investigated with respect to corrosion, which include new and used ones collected at the field. Tensile strengths and elongations appeared to decrease when the wires were exposed to corrosive environments. The amount of decrease was more prominent as environmental conditions became more corrosive. They are also vibrated with some amplitude everytime pentographs touch contact line. The frequent cyclic load on the wire may result in a fatigue damage. Surface damage by corrosion can make fatigue crack initiate with ease. In the present study, the fatigue life of the used wire was measured 50 to 60% compared with that of new one in average.

• Tunnel and Underground Space
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• v.9 no.3
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• pp.175-184
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• 1999

Systematic measurements in the field are the key component in the design process to ensure that optimal and safe designs result. The instruments installed at the Waste Isolation Pilot Plant, a underground nuclear waste repository in U.S., for measuring rock deformation was reviewed. Also discussions about installation and measurement for better understanding the complex time-dependent deformational behavior of underground excavation were made.

• 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.

• KSBB Journal
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• v.13 no.1
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• pp.31-37
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• 1998

A simple method for the in vivo production of third-stage infective juveniles(IJs) of Steinernema glaseri was developed. Using Galleria mellonella larvae, only IJs can be rapidly generated inadequate quantities for field application. The nematode inoculation concentration and incubation temperature were critically important. The most effective temperature for infectivity of Steinernema glaseri IJs to Galleria mellonella larvae was 33$^\circ C$. However, the total number of menatodes harvested at 25$^\circ C$ about 66,000 IJs per larva was significantly greater than those at other temperatures. The optimal inoculation number of nematodes was 60 to 80 nematodes per host larva. The higher nematode inoculation concentration of 100 IJs per larva caused a rapid decrease in the total number of IJs harvested. As the inoculation medium pH increased, the number of IJs harvested increased and reached about 110,000 IJs per larva at pH 9.0. The pathogenicity of IJs decreased y increasing the salt concentration in the medium.

• Journal of the Korean Society of Costume
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• v.29
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• pp.85-98
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• 1996

WE SELECTED 30 SORTS OF PLANT-DYES WHICH WE CAN GET EASILY AROUND US DYED TEXTILE FABRICS THROUGH EXPERIMENTAL STUDIES AND GOT SEVERAL GOOD COLORS AS FOLLOWS WITH HISTORICAL REVIEW-ING ABOUT THE TRADITIONL NATU-RAL DYEING. 1. We got the colors of brown most com-monly yellow the nest black green and red in order of frequency 2. It is dyed more rapidly beautifully and deeply to the silk than to the cotton. 3. Salt worked the colors deeply K2CO3 more light FeSo47H2O more darkly and Alum the most beautifully and brightly as a mor-dant. 4. natural plant dyes contains various sorts of colors and we could confirm the possibility to create the composed implicit and secondary and tertiary colors through dual method of dyeing which couldnt's be got in the field of modern chemical dyes.

• Journal of Magnetics
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• v.14 no.4
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• pp.165-167
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• 2009

Nano-sized Yttrium iron garnet (YIG;$Y_3Fe_5O_{12}$) particles have been synthesized by using coprecipitation and a heat treatment process. The YIG particles were made using a nitrate or a chloride salt solution. The pH concentration of the solution was fixed at 12. Spherical shaped YIG particles were made with a size of about 20 nm. The magnetization value of the particles was smaller than the bulk value but their coercive field showed a high value.

• Proceedings of the KSR Conference
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• 2001.10a
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• pp.139.1-146
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• 2001

Contact lines are necessary to supply electric locomotives with electric power. As most railways are gradually electrified with modernized electric cars, the demand for catenary wires and their facilities are also increased. Catenary wires made by metallic materials are generally used in the open air. They are exposed to the marine area with air-borne salt or severely polluted industrial area with much corrosive emission gases depending on the railway locations. In urban area, acid rain may cause a degradation of catenary wire system. Corrosion of catenary wires can make their actual lifetime shorter than that originally designed. Thus, the messenger wires, a kind of catenary wire system, were investigated with respect to corrosion, which include new and the used one collected at the field. They are also vibrated with some amplitude everytime the train passes through the railway. The frequent cyclic load on the wire any result in a fatigue damage, Surface damage by corrosion can make fatigue crack initiate with ease. In the present study, the fatigue life of the used wire was measured 40 to 50% shorter than that of new one in average.