• Journal of Environmental Science International
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• v.2 no.3
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• pp.201-206
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• 1993

The concentration of Total Suspended Particulates(T.S.P), size distribution of suspended particulates, and soluble anions of T.S.P in atmosphere of industrial region in Busan were investigated. T.S.P was measured by High-Volume Air Sampler and particle size distribution was measured by Anderson Air Sampler. We analyzed the chemical component of the T.S.P by ion Chromatography and measure4 the shape and size of T.S.P by Scanning Electron Micrography The small size of T.S.P mainly exist in industrial region, but the large size of T.S.P mainly exist in residentail area.

• Microbiology and Biotechnology Letters
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• v.24 no.3
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• pp.261-267
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• 1996

To examine the potential utilization of chitosan, the biodegradable natural polymer, as a control agent of apple white rot caused by Botryosphaeria dothidea in a new control measure by coating it on the diseased branches, the various antifungal activities of chitosan was investigated. Chitosan showed significant inhibitory effect on the mycelial growth of B. dothidea, along with the morphological changes including hyphal swelling and ultrastructural changes on solid PDA medium. In liquid PD broth medium, the chitosan showed more significant effect on the growth of B. dothidea also forming cell clusters indicating affection on the hyphal extension. The growth of B. dothidea was inhibited more than 90% at the concentration of 1.0 mg/ml. Chitosan also detained the spore germination and induced the morphological change of germ tubes. Glucosamine, monomer of chitosan, did not affect on the growth of B. dothidea indicating the antifungal activity was caused by chitosan polymer.

• Proceedings of the Korea Concrete Institute Conference
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• 1999.10a
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• pp.675-678
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• 1999

Rebar corrosion in concrete containing both chloride ions and calcium nitrite inhibitors were investigated by the various electrochemical methods. Rebar corrosion was accelerated by applying the impressed current to the rebar in concrete. Effect of chloride content and inhibitors on rebar corrosion were evaluated. Accelerated corrosion technique is the method to measure the time to the initiation of cracks of reinforced concretes, by applying constant voltage between rebar and the stainless steel cathedes. The increase of concentration of chloride ions in concrete result in the increase in anodic currents and the reduction of time to crack. However addition of inhibitors did not improve corrosion resistance of rebar in concrete. Rebar corrosion in concrete with chloride ions and inhibitors was also analyzed by the immersed tests though the mesurement of corrosion potentials.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2000.04a
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• pp.163-166
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• 2000

Fiber Bra99 grating (FBG) sensor, one of the fiber optic sensor (FOS) offers lots of advantages for structural health monitoring due to its multiplexing capability. Also, it is proper to measure the structural vibration with no mass concentration effect. In this paper, we constructed two sensor arrays composed of 9 FBG sensors for the vibration and mode sensing of a composites beam. For an accurate measurement of wavelength shift, a signal processing board with an electric circuit based on time-interval counting was developed. This sensor system showed a good resolution of dynamic strain (<10${\mu}{\varepsilon}$). Using this sensor system, dynamic strains at 9 points of composite beam was measured and strain measured mode shape of the beam was calculated from the acquired strains and compared with numerical results by ABAQUS.

• The Mathematical Education
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• v.45 no.1 s.112
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• pp.25-34
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• 2006

In this paper, we focus on the creative attitude in mathematics as one aspect of mathematical creativity. To measure the creative attitude, we first introduce some prior studies and CAS (Creative Attitude Scale) designed by Noboru Saito in Japan. We develop the CAS-K (Creative Attitude Scale-Korea) including 33 items of 7 factors based on CAS which has 27 items. The factors are fluency, appropriateness, positiveness, independency, concentration, convergency, and accuracy. In CAS-K, it is important to give the information about students' creative attitude for each factor. Thereby, CAS-K can be useful sources of creative attitude to foster mathematical creativity. Rather than the total scores, we emphasize applications and results from CAS-K relating to the 7 factors.

• Journal of Periodontal and Implant Science
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• v.26 no.3
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• pp.681-688
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• 1996

Periodontal regeneration requires the migration and proliferation of gingival fibroblasts and periodontal ligament cells. These cellular events are influenced and regulated by growth factors and some drugs. The purpose of this study is to examine the effect of Rhizoma coptidis and Centella asiatica extracts on human gingival fibroblasts. Gingival fibroblasts were primarily cultured from extracted premolar with non-periodontal diseases. Cells were cultured with ${\alpha}-MEM$ at $37^{\circ}C$, 5% $CO_2$, 100% humidity incubator for 2 or 3 days, as a measure of cell proliferation potential, it was examined that the DNA synthesis using $[^3H]-thyrnidine$ incorporation, the cell numbers (with or without dye), and cell viabilities. Rhizoma coptidis is increased the proliferation of gingival fibroblasts at concentration of $10^{-9}g/ml$, but Centella asiatica is decreased the proliferation at all concentrations. This study demonstrated that Rhizoma coptidis is a potential mitogen for human gingival fibroblasts in vitro, and we can expect the usefulness of this drug in periodontal regeneration.

• 한국생물공학회:학술대회논문집
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• 2003.04a
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• pp.128-131
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• 2003

The effect of microwave irradiation on waste activated sludge was investigated in order to improve solubilization. a different levels of microwave irradiation time were varied within a range from 1 min to 15 min. When WAS was pretreated at 1, 3, 5, 7, and 15 min, the SCOD concentration increased according to microwave irradiation time. A simple batch procedure was used to measure the VFA potential, i.e. the amount of VFA that can be formed through digestion of organic constituent in sludge. At equilibrium point, TVFA in the case of 1, 3, 5, 7 and 15 min microwaved sludges was 8%, 122%, 243%, 279% and 232% higher than that in the case of raw sludge, respectively.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.3 no.1
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• pp.62-69
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• 2000

Topography influences shallow landslide initiation through both concentration of subsurface flow and the gradient on slope stability. A model for the topographic influence on shallow landslide initiation developed by Mongomerry et al (1994) is applied to 24 places with similar terrain and subsurface flow. The criterion of landslide prone areas developed by Korea Forestry Administration (1998) is likely to misinterpreted under the condition of heavy rainfall. Soil saturation can be predicted by this model. This relative soil saturation can be used to analyze the stability of each topographic point in the case of cohesionless soils with spatially constant thickness and saturated conductivity. The three different stages of steady state rainfall predicting to cause instability in each topographic points provide a good measure of shallow landsliding possibility.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.26 no.6
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• pp.817-822
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• 2002

Sooting characteristics of counterflow ethylene/propane mixture flames have been experimentally studied to investigate the fuel structure effect on PHM and soot formation. Laser-induced incandescene and laser-induced fluorescene techniques were employed to measure soot volume fraction and polycyclic aromatic hydrocarbon (PAH) concentration, respectively. Importance of $C_{3-}$species on PAH growth as well as the H-abstraction-C$_2$ $H_2$addition (HACA) mechanism has been emphasized, considering that PAH growth rate is greater for with mixed fuel than fer pure fuel flames. It was also confirmed that HACA pathways are the dominant soot growth mechanism. A new PAH growth model including both $C_{2-}$ and $C_{3-}$growth mechanisms is proposed based on the experimental results.

• Journal of Environmental Health Sciences
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• v.27 no.3
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• pp.57-62
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• 2001

The study was conducted to measure the heavy metal pollution of soils at the playground for children and to investigate the characteristics of heavy metals distribution I city. The studied area was divided into two: the residential area and the industrial area. The samples of the sands and soils were collected from both areas. The results were obtained as follows. All average concentration of 6 different heavy metals was found to be lower than the standard of soil pollution. Zn, Pb and cu concentrations were higher than other species of heavy metals. The contents of heavy metals in the soil were higher than the sands. The average contents of Zn, Pb, Cu, As, Hg and Cd in soil were 38.36, 9.53, 7.31, 0.03, 0.18 and 0.09 mg/kg respectively. Comparing with the residential area, heavy metal concentrations of the industrial area were 4.60, 1.49, 2.60 and 4.29 times for Zn, Pb, Hg and Cd in soils, respectively.