• Journal of Life Science
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• v.13 no.5
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• pp.582-589
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• 2003

The effect of useful rhizobacterium added in bed soil on the early growth promotion of red pepper plug seedlings was investigated. Total 540 colonies of rhizobacteria from 385 samples of eggplant family roots were isolated. Among these, 5 isolates were selected for antifungal activity against pathogenic fungi such as Alternaria solani, Botrytis cinerea, Fusarium oxysporium, Phytophthora capsici, and Sclerotia sclerotiorum. Of all the isolates, MJ-3 having the most pronounced growth-promoting ability for red pepper was finally selected and identified as Bacillus amyloliquefaciens through characterization of biochemical and bacteriological aspects and 16S rDNA sequence. The plant height, stem diameter, root length and fresh weight of red pepper plants which were grown with inoculation of B. amyloliquefaciens MJ-3 were higher than those without inoculation. Especially the root weight of the inoculated red pepper plant increased by 44.3%, the content of endogenous plant hormone (CA$_1$) being 0.556 ng/g (dry weight).

• KSCE Journal of Civil and Environmental Engineering Research
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• v.9 no.3
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• pp.49-56
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• 1989

Recently, a growing attention is paid to the development of new construction materials. The fiber-reinforced concrete is recognized as one of the most promising new construction materials. A comprehensive experimental study was conducted to explore the mechanical behavior of steel fiber reinforced concrete. The major variables in the experiment were the fiber contents and the lengths of steel fibers. The flexural, tensile, and compressive behavior of steel fiber reinforced concrete were investigated. The present study shows that the strength and ductility are remarkably increased with on increase of fiber content. The rate of strength increase due to steel fibers was found to be the highest in tension, the middle in flexure, and the lowest in compression. This indicates that the steel fibers play a major role in increasing the tensile capacity. The present study gives a thorough examination on the mechanical behavior of steel fiber reinforced concrete and allows more realistic use and design of steel fiber reinforced concrete.

• Journal of the Korea institute for structural maintenance and inspection
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• v.20 no.5
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• pp.102-108
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• 2016

The purpose of this study is to examine the reduction effect of shrinkage reducing agent for drying shrinkage induced cracking and suggest the method of controlling the cracking in concrete box culvert for power transmission. Based on drying shrinkage cracking mechanism, it is necessary to perform the numerical analysis, which involves shrinkage reducing effect of shrinkage reducing agent. From the numerical results, it is found that cracking behavior for longitudinal direction and transverse direction due to differential drying shrinkage of box culvert can occur and the experimental observation of concrete cracks support the numerical predictions. The shrinkage reducing agent reduced the concrete cracking by 40~50%, which shows the methodology of controlling of drying shrinkage cracks in box culverts in real construction site.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.925-928
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• 2008

Fiber is an important ingredient in strain-hardening cementitious composite (SHCC), which can control fracture of cementitious composite by bridging action. The properties of reinforcing fiber, as tensile strength, aspect ratio and elastic modulus, have great effect on the fracture behavior of SHCC. To apply SHCC to structural member, SHCC must have economical efficiency and workability as well as own excellent tensile performance. For these purposes, four-point bending and direct tensile tests on SHCC with only hybrid synthetic fibers, total fiber volume fraction, $V_f$, is 1.5%, are carried out. The research emphasis is on the mechanical properties of SHCC made in Polyvinyl alcohol (PVA) and Polyethylene (PE) fibers, and how this affects the composite property, and ultimately its strain-hardening performance. Also, effect of hybrid type and water-cement ratio on the behavior of SHCC was evaluated in this paper.

• Journal of Korean Society of Forest Science
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• v.102 no.2
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• pp.182-188
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• 2013

In this study we investigated that the mountain-cultivated ginseng into persimmon vinegar fused material on blood lipids and anti-oxidant capacity in rats. A 4-year-old mountain-cultivated ginseng was ripened with 4-year-matured persimmon vinegar, and then it was diluted 5 times and orally administerd to rats. The rats were divided into a control group (CON), a persimmon vinegar group (PV) and a mountain-cultivated ginseng + persimmon vinegar fusion material group (MPV). The body weight was found to be low in MPV, and amount of the stored fats were also low in PV and MPV. Blood lipids were found to be low in PV and MPV compared to the CON. HDL-C (high density lipoprotein cholesterol) was found to be significantly high in these two groups. Liver Cu,Zn-SOD (superoxide dismutase) and GPx (glutathione peroxidase) were CON < PV < MPV, in sequence, with significance. Especially, it was the highest in MPV. Liver MDA (malondialdehyde) concent was MPV < PV, CON, in sequence, with significance. These results suggested that the fusion material lowers blood lipids and enhance anti-oxidant capacity. We carefully thought that it might be used effectively as a health food.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.557-560
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• 2008

Fiber reinforcement has been being widely used in concrete to enhance the mechanical properties and to reduce the micro-cracking caused by plastic and drying shrinkage. While researches has been focused on the benefits of fiber reinforcement, the properties of fiber reinforced concrete are strongly dependent on the type, shape and the amount of fibers in concrete. In this study, the resistance of nylon fiber reinforced concrete against the chloride ion penetration was experimentally observed by NT Build 492. The test results showed that the addition of nylon fiber has little effect on the change of the resistivity of concrete to the chloride ion penetration.

• Magazine of the Korea Concrete Institute
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• v.8 no.5
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• pp.189-200
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• 1996

The permeability of concrete influences the durability of concrete remarkably. The conventional test method for permeability is very difficult to apply to high strength concrete because of its very low permeability. The present study employs a resonable and realistic test method for permeability of concrete and proposes a very low permeability concrete. To this end, comprehensive tests have been conducted and major test variables include the types and amount of cement. the types and amount of admixtures, and the size of aggregates. The present test results indicate t h a t the permeability decrease with the increase of strength and that the concrete with certain mineral admixtures exhibits very low permeability. The permeability of those high performance concrete is about 1/100 of conventional normal concrete. The present study provides a firm base for the use of very low permeable and hence very durable concrete.

• Magazine of the Korea Concrete Institute
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• v.7 no.5
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• pp.179-188
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• 1995

SFRC overcomes brittleness of concrete and has increases strength due to the action of confmement, crack arrestmg mechan~sm and pull out resistances of steel f~bers ~ n s ~ d e the concrete. These lead also to the increased strength and ductility under the shear stress. It has been reported that the secondary remforcement effect of steel fibers IS more pronounced In shear than flexure. Addition of hooked stee!, fibers into the cementitious materials enhanced shear resistance and consequently improves structural behavior and shear strength of Reinforced Hooked-Steel-Fiber Concrete Ream(RHSFCI3) under the shear forces. Experimental observations were made on the main parameters effecting structural behavior of RHSFCB in this study. The volume fractions of fibers, shear span to depth ratios, and spaclngs of stlrrups were taken into account as the mam parameters. Some eyuatlons reported in the literatures, regardmg the predict~ons of the shear strength of RHSFCB have been evaluated stdtlst~cdlly based on the tot a1 number of 95 test results on RHSFCB faded In shear on shear flexu~al mode.

• Journal of the Korea institute for structural maintenance and inspection
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• v.10 no.2
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• pp.143-152
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• 2006

High performance concrete(HPC) has been widely used in high-rise building. The HPC has several benefits including high strength, high fluidity and high durability. However, spalling is susceptible to occur in HPC and HPC also tends to be deteriorated in the side of fire resistance performance at fire. This paper investigated the spalling prevention of high performance RC column. Control concrete showed severe failure and a case of concrete with fire enduring spraying material exhibited more severe spalling failure than even control concrete. In addition, concrete with fire enduring paint reported the most favorable spalling resistance effect for preventing spall, compared with other concrete covered with finishing materials, such as fire enduring spraying material, gypsum board, marble board and fire enduring PC board. Meanwhile, concrete adding 0.1% of PP fiber demonstrated spalling resistance performance after 3hours load bearing test.

• Korean Journal of Organic Agriculture
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• v.7 no.1
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• pp.137-146
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• 1998

Various rhizobacteria was isolated, and was bacterialized into the substrates to clarify the plant growth promoting effects of rhizobacteria on the early growth of red peper seedlings. Total 125 bacterial isolates were primarily isolated and purified from the soils in greenhouse. And four strains were finally screened, based on the antifungal activities against Fusarium sp., Pythium sp. and Rhizoctonia sp. of red pepper plants. The strongest antifungal strain RB 109 has a antagonistic activity against Fusarium sp., Pythium sp. and Rhizoctonia sp. in terms of 66.0%, 65.0% and 66.1%. Early growth of red pepper seedlings was promoted, when cultured solution of rhizobacteria RB 109 was bacterialized into the substrates. Antifungal rhizobacteria RB 109 was identified as Pseudomonas sp. related strains, which has a similarity of 82% to the Pseudomonas sp.