• Bulletin of the Korean Chemical Society
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• v.34 no.11
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• pp.3261-3264
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• 2013

Carbon nanocomposites composed of carbon nanostructures and metal nanoparticles have become one of useful materials for various applications. Here we present the preparation and antibacterial activity of CNT-Ag and GO-Ag nanocomposites. Their physical properties were characterized by TEM, XPS, and Raman measurements, revealing that size-similar and quasi-spherical Ag nanoparticles were anchored to the surface of the CNT and GO. The antibacterial activities of CNT-Ag and GO-Ag were investigated using the growth curve method and minimal inhibitory concentrations against Gram-negative and Gram-positive bacteria. The antibacterial activities of the carbon nanocomposites were slightly different against Gram-positive and Gram-negative bacteria. The proposed mechanism was discussed.

• Journal of Power System Engineering
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• v.14 no.6
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• pp.29-34
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• 2010

As the steam temperature of fossil power plant boiler is increasing, the use of 9Cr-1Mo high alloy material is prevalent and it is needed to investigate the characteristics of low cycle fatigue for high alloy and austenite stainless steel that has used up to recently. As a result of test, in 9Cr-1Mo high alloy steel, the relation of strain and fatigue life is non-linear and the crack mode of low cycle fatigue is brittle but in the austenite stainless steel, that of strain and fatigue life is linear and the crack mode of low cycle fatigue is ductile. Comparing the fatigue life between high alloy and austenite stainless steel, there is no consistent characteristics as to strains. But the fatigue life of 9Cr-1Mo steel is longer by 25% than that of STS304 stainless steel in the relatively low, 0.3% strain. In the other strain, the fatigue life of two materials is similar.

• The International Journal of Costume Culture
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• v.4 no.1
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• pp.9-17
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• 2001

The purposes of the study are to find out the effect of clothing colors on perception of stimulus ages, occupations and images using stereotyping and color vision theories. The research method is a qualitative study and materials developed for the study are a set of stimuli and open-ended responses. The subjects were 1138 undergraduate students in Taejoen city, Chungbuk province. The data is analyze using content analysis, supplementary frequency and χ²analysis. The results are as follows : 1) The colors in Korean traditional costumes affected on the wearer's age perception : The red ensemble give the wearer the youngest look while the gray give the oldest look. 2) Mono-color ensemble wearers tend to give older look than bi-color ensemble wearers. 3) The chima colors and the jogori colors have similar impact on the wearer's age perception. 4) On image perception the jogori colors have more impact than the chima colors. 5) The colors in Korean traditional costumes are the clues to estimate the wearer's occupation.

• 한국기계연구소 소보
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• s.19
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• pp.43-52
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• 1989

Material damage of Unifiner Change Heater: Tube used for nearly 20 years was evaluated and Mechanical tests such as tensile tests and creep-rupture tests were conducted to predict the residual life. After the investigation, any major damage or degradation was not found except the welded zone. Microstructural observation showed that most of delta-ferrite was transformed. to sigma-phase and consequently, the ductility was very much reduced. A KLA(Knife-Line Attack) crack with 60mm in length and 2.8mm in depth was found just near the welded zone, which is believed to be caused by intergranular corrosion. Creep-rupture tests, which are very essential to predict the residual life, showed that both used base and weld metals have similar results with the reference data.

• Journal of the Korean Solar Energy Society
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• v.33 no.1
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• pp.66-72
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• 2013

In this study, the thermal conductive characteristics and basic properties of the nine commercial products of bentonite grouts were studied. Six of the nine products for ground heat exchanger systems are imported and others for civil engineering are domestic. The thermal conductivities of all bentonite products are nearly similar among products. The free swell indexes, viscosities and filter losses of the ground heat exchanger grouts are lower than those of the civil engineering ones. These characteristics seem to increase of the fluidity to fill the bentonite slurry to bore-hall perfectly, rather than to prevent underground water penetration. Thus, the mixtures of bentonites and sands are recommended for high thermal conduction grouts.

• Korean Journal of Bronchoesophagology
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• v.8 no.1
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• pp.22-28
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• 2002

Background and Objectives : The aim of the this study is to determine the efficacy of an external prosthesis made of ringed Polytetrafluoroethylene to prevent Postanastomotic stenosis after surgical correction of extensive tracheal defects in rabbits. Materials and Methods : Thirty rabbits were used, divided into two groups of 15 animals each. Group A rabbits underwent resection of six-ring segments of the cervical trachea and tracheal end-to-end anastomosis. The Procedure used in group B was similar to that used in group A. but the tracheal anastomosis was supported by an external ringed polytetrafluoroethylene prosthesis. After six months, rabbits were killed and tracheas were resected and then compared the postanastomotic tracheal stenosis using morphometry. Results : Anteroposterior diameter, transverse diameter, cross sectional area and intra luminal perimeter of trachea was greater in group B than group A. Also inflammatory changes of mucosa and submucosa were greater in group A than group B. Conclusion : A ringed PTFE as a external stent was effective to prevent tracheal stenosis resulting from the extensive tracheal resection and tracheal reconstruction in rabbits.

• Animal cells and systems
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• v.10 no.2
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• pp.109-114
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• 2006

A study on marine sponges was conducted with the materials collected by SCUBA diving in Hongdo and Gageodo Islands, Korea from September 2004 to July 2005. Clathria (Clathria) hongdoensis n. sp. and Clathria (Clathria) sohuksanensis n. sp. turned out to be new to the science. Clathria (Clathria) hongdoensis n. sp. closely seems to C. (C.) acanthstyli Hoshino (1981), based on their spicules type. However, they differ in the size of spicules and growth form. Clathria (Clathria) sohuksanensis n. sp. is similar to C. (C.) bicalthrata Hooper (1996), except for lacking small toxas.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 1999.10c
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• pp.271-276
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• 1999

This study is performed to evaluate an elastic properties and acid-resistance of concrete using pine needle ash(PNA). Materials used for this experiment are PNA , normal portland cement, natural fine and coarse aggregate. Test results show that the highest ultrasonic pulse velocity , dynamic and static modulus of elasticity is achieved by 5% PNA filled PNA concrete, which has showed similar with those of thei normal cement concrete. Acid-resistance of PNA concrete is increased with increase of the contnet of PNA , it is 1.29 times of the normal cement concrete by 5% PNA fille PNA concrete an d2.57 times by 15% PNA filled PNA concrete . Accordingly , PNA concrete wil greatly improve the properties of concrete.

• Journal of the Society of Naval Architects of Korea
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• v.42 no.6 s.144
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• pp.637-643
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• 2005

A new novel Whipping Factor is proposed as a measure of the ship damage potential due to an underwater explosion bubble pulse. The factor was derived from the relationships among the charge weight, its depth and the fluid acceleration due to pulsating gas bubble. From the whipping response analyses for three uniform Timoshenko beams with similar characteristics of real naval surface ships, we have confirmed the maximum bending moment responses of beams due to whipping are almost same if the applied whipping factor is constant regardless of the charge weights and depths, which could validate the proposed whipping factor.

• Journal of Industrial Technology
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• v.27 no.A
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• pp.121-130
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• 2007

Centrifuge model tests were performed to find appropriate equations proposed previously of estimating the bearing capacity of the composite clayey soil reinforced with sand compaction pile. Model tests were carried out with changing the replacement ratio of SCP (20%, 40%, 70%), contents of fine materials (5%, 10%, 15%) and ratio of treated width to loading width (1B, 2B, 3B). Test results about bearing capacity of the composite ground were obtained by performing the surcharge load tests with measurements of applied loads and vertical displacement. Bearing capacities against bulging and shear failures were estimated by the existing equations. As results of comparing the estimated bearing capacity with experimental values the bearing capacities estimated by Greenwood's equation (1970) for bulging failure mode were similar to the test results.