• 한국생물공학회:학술대회논문집
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• 2002.04a
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• pp.449-452
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• 2002

A filamentous microorganism was isolated from completely rotten wood for the production of cellulolytic enzyme. The Trichoderma sp. FJ1 produced a large amount of cellulolytic enzymes, such as CMC, xylanase, ${\beta}-glucosidase$, and avicelase. For the production of the enzymes, when cellulolsic wastes were used as carbon sources of strain FJ1, rice straw showed higher enzyme activities than sawdust and pulp. The activities of CMC, xylanase, ${\beta}-glucosidase$, and avicelase were 2.95, 5.89, 0.45, and 0.12 U/ml in use of rice straw, respectively. To enhance production of the enzymes, the mixture substrate of rice straw and commercial cellulosic materials was investigated as carbon sources. The highest activities of CMCase, ${\beta}-glucosidase$, and avicelase were found in the mixture of rice straw and avicel, particularly rice straw:avicel (50:50), and the highest xylanase was obtained in the mixture ratio of 71:29. Bacto peptone addition of 0.1% showed enhanced production of the cellulolytic enzymes in which the activities of CMCase, xylanase ${\beta}-glucosidase$, and avicelase were 19.23, 27.18, 1.28, and 0.53 U/ml, respectively. The production of the enzymes using rice straw was efficiently induced in present of avicel and pulp containing high content of cellulose. Consequently, the filamentous microorganism, strain FJ1 utilized various cellulosic wastes as carbon sources and cellulases productivities were excellent compared to those of others strains reported previously, suggesting that the strain FJ1 will be expected as a favorable candidate for biological saccharification of cellulosic wastes in further.

• Magazine of the Korean Society of Agricultural Engineers
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• v.41 no.5
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• pp.93-98
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• 1999

The results of an experimental investigation on the characteristics of compaction and compressive strength of polypropylene fiber reinforced soil are presented in this paper. This study has been performed to obtain the physical properties of PFRS(polypropylene fiber reinforced soil) such as strain-stress relationships, OMC(optimum moisture contents) and ${\gamma}$dmax (maximum dry unit weight), with four different contents (i.e., 0.1%, 0.3%, 0.5% and 1.0% weights ) of mono-filament and fibrillated polypropylene fibers. From the compaction test results, it is found that OMC increased with the contents ratio of fiber, but ${\gamma}$dmax decreased. It means that the improvement of the workability and the reduction of the weight of embankment structures by the asddtion of the polypropylene fiber. And, from the compression test results, it is found that the additon of the polypropylene fiber remarkably improved the compressive strength of PFRS. And it was observed in the viewpoint of strength that the fibrillated polypropylene fiber reinforced soil is more effective than the mono-filament polypropylene fiber reinforced soil.

• Journal of Sericultural and Entomological Science
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• v.33 no.1
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• pp.9-12
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• 1991

A study on dyeing-rate for single and mixture dyeing of silk with acid dyes was carried out. Single and mixture dyeings were performed with levelling and milling dyes at 7$0^{\circ}C$ and at pH 3, pH 4 and pH 5, respectively. The results of this study were summerized as follows : 1. C. I. Acid Orange 7. A) At pH 3, dyeing-rate was more fast in the single dyeing than in mixture dyeing at the beginning of dyeing process. B) At pH 4 and 5, dyeing-rates tend to get very similar in single and mixture dyeing. 2. C. I. Acid Blue 138 A) At all pH value, dyeing-rates were more fast in the mixture dyeing than single dyeing at the beginning of dyeing. B) As the time increased, the difference of dyeing-rate and adsorption amounts between single and mixture dyeing was not shown.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.4A
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• pp.775-785
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• 2006

This study focused on the development of surface deformations of GFRP rebars with a better bond characteristic for reinforcing concrete, and simultaneously, of GFRP rebars with more simple and economic production process. This research paper describes a development and bond performance of GFRP rebar with molded deformations, which is composed of polymer resin and milled glass fiber. To determine proper mix ration of milled fibers, material test of hardened epoxy and pullout tests of GFRP rebar with various mix ratio were conducted. The test results indicate that the new strategy of using a mixture of epoxy resin and milled fiber could be successfully applied to a surface structure of GFRP rebar to enhance bond with concrete. The bearing resistance of the ribs was further enhanced by the milled fibers at mechanical and environmental loading state.

• Journal of Korea Foresty Energy
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• v.21 no.2
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• pp.62-68
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• 2002

Adiabatic property of plywood wall panel was examined to evaluate their thermal conductivities. The amount of heat loss was investigated through overall heat transmission experiment. Styroform and grass wool showed less heat loss. However, yellowsoil board and laminated lumber showed high volume specific heat capacity. When the changes of indoor and outdoor temperature were checked in model house, wall manufactured with styroform and grass wool was affected easily by the changes of outdoor temperature. Yellowsoil, the mixed board of yellowsoil and sawdust, and laminated lumber, which have high volume specific heat capacity, were not affected much. The rates of overall heat transmission were much better in styroform and grasswool, but the adiabatic properties were much higher in yellowsoil board and the mixed board of yellowsoil and sawdust. The results showed that the insulating material can be developed using yellowsoil and wood, which are nature friendly materials.

• Polymer(Korea)
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• v.33 no.5
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• pp.429-434
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• 2009

In this study, electro spinning conditions for PMMA were studied. Namely, the ratio of DMF and THF and its maximum concentration were examined. Conductivity of the polymer solution containing silver nanoparticles and its effect on fiber diameter were also studied. As the results, the maximum concentration for the electro spinning of PMMA was found at 18 wt%, and the ratio of DMF/THF was 7:3. The diameter of nanofibers obtained was 100-400 nm when the PMMA solution containing 1000 ppm silver was electrospun. It was found, from TEM results, that silver nanoparticles were distributed on the edge of fibers and the resulting nanofiber mats showed a good antibacterial activity.

• Journal of the Korea Convergence Society
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• v.11 no.5
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• pp.35-41
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• 2020

This study was conducted to develop the efficient system for starch hydrolysis suppression using rutin, quercetin and dietary fiber through the statistical mixture design. The three components were replaced with wheat flour at the level of 10% and the mixed gel with three components was characterized by in vitro starch digestion. The mixture design was applied by simplex-centroid experimental model. The quadratic model (R²=0.86) was well fitted and the obtained regression equation indicated that the significant positive effects was observed in the quercetin and fiber mixture. Based on the statistical results, the best mixing ratio of quercetin and fiber was 72: 28 that led to the lowest predicted glycemic index (pGI). Their interactions on the pGI of starch digestibility were clearly visualized in the 3D surface plot. These results suggested that the mixture of quercetin and fiber interact strongly with wheat flour, consequently retarding starch hydrolysis by 15%.

• Journal of the Korea Concrete Institute
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• v.27 no.3
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• pp.291-298
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• 2015

In this paper, a bundled diagonal reinforcement using high performance steel fiber was proposed to enhance the construct ability and seismic performance. Experiments of coupling beam was composed of four specimens and the hysteretic behavior evaluated for reverse cyclic loading to specimens using high performance steel fiber. The main variables of the experiment is a amount of stirrup and bundled reinforcement, depending on whether the mix of steel fiber. Specimen which criteria was applied 100% of stirrup and bundled diagonal reinforcement of ACI318 criteria. With this, by appling same diagonal reinforcement, two specimens were created by adjusting stirrup of 75%, 50%. So, a total of four specimens were produced. When coupling beam was placed concrete, this experiment was mixed in a content of steel fiber 1%. All the specimens were produced by aspect ratio 3.5(l/h=1050/300) to a half-scale. In this result, two specimens as reduced to stirrup of 75%, 50% was no significant difference in the strength, stiffness and energy dissipation capacity, respectively compared to the stirrup of 100%.

• Journal of the Korean GEO-environmental Society
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• v.21 no.12
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• pp.35-41
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• 2020

Recently, underground spaces have been developed variously due to the concentration of the building structure in downtown area and reconstruction of the apartment. However, various problems such as differential settlement are occurring in the waterproof and reinforcement construction. In grouting method, which is frequently used for the ground reinforcement, quality control was performed by measuring the injection quantity of grouting materials and performing laboratory tests using boring samples, but it is difficult to determine whether the ground reinforcement has been performed properly during the construction stage. In order to solve this problem, a research is needed to carry out quality control by measuring electric resistivity after grouting is performed using grouting materials mixed with conductive materials. In this research, as a basic study of the new grouting method using conductive materials, uniaxial compression tests were performed using cement specimen with 0, 3, 5, 7% of carbon fiber to evaluate the effect of conductive material on the performance of grouting material. Based on the test results, the uniaxial compressive strength is increased with the mixed proportion of the carbon fiber increase. Furthermore, the carbon fiber can also affect on the early-strength of the grouting materials.

• Applied Biological Chemistry
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• v.29 no.1
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• pp.36-43
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• 1986

In order to produce cellulosic single cell protein from the cellulose, 163 strains of cellulose assimilating bacteria were isolated from 95 sources and one of them was screened by its strong cellulose assimilating activity. and was identified as Sporocytophaga congregate A-7. The optimum temperature and pH for cellulase production were $30^{\circ}C$ and 6.0, and the optimum temperature, pH and heat stability of the enzyme were $50^{\circ}C$, 7.0 and below $55^{\circ}C$. When the bacteria was cultured in fermentor, the specific growth rate was $0.034hr^{-1}$ and when the bacteria was mixed cultured with Candida guilliermondii var. guilliermondii, the specific growth rate of the bacteria and yeast were $0.06hr^{-1}$ and $0.08hr^{-1}$ respectively and total cell dry weight was $4{\sim}5g/l$.