• Proceedings of the Korea Concrete Institute Conference
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• 2000.04a
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• pp.66-71
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• 2000

Recently, great efforts and investment have been made in order to achieve economical production by applying new methods like minimization of man-power into construction field. Therefore in this study, we have been focused on the development and practical using of high of high flowing concrete with fly ash, superplasticizer and viscocity agent, also we find out the optimum mix proportions to accomplish good wuality high flowing concrete. The results of this study show that high flowing concrete with the ratio of fly ash replacement of 20%, viscosity agent of 300g/㎥ and superplsticizer 2.0%(C$\times$%) in W/B of 35, 45% has better performance than the high flowing concrete without fly ash replacement

• Journal of the Semiconductor & Display Technology
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• v.18 no.3
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• pp.47-51
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• 2019

The three different polymer compounds were manufactured with the three different fire retardant (silane coated magnesium dihydroxide) contents, 180, 200, 220 phr, for making cable sheath for ship industry. In the research, ethylene-vinylacetate, polyethylene as matrix polymers and ethylene-vinylacetate grafted maleic anhydride as coupling agent were selected for compounding with fire retardant, closslinking agent, plasticizer, and other additives. In the evaluation. ΔT, Mooney viscosity, and tensile strength increased with the content of fire retardant. But it was found that too much fire retardant damaged aging resistance and cold resistance of the polymer compound.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.11a
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• pp.765-768
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• 2006

This paper investigates the properties of light weight foamed concrete with variances in adding ratio of stability agent(PS). Test showed that an increase of PS adding ratio decreased fluidity due to higher viscosity and increased unit weight of specimens. A sinking depth declined as the adding ratio of PS inclines, but all specimens including control concrete was ranging in KS; 0.5 to 10mm. Compressive strength value of specimens increased as PS adding ratio inclines. As for the tensile strength, any significant feature was not observed, compared with control concrete, but the ratios of camp. to tens. increased. Appearance density of concrete increased, and thermal conductivity was satisfied in KS, except for a specimen adding 0.07 percent of PS.

• Journal of Electrochemical Science and Technology
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• v.9 no.4
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• pp.339-344
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• 2018

The gelling agent used in Zn-air cells plays a role in improving battery life. It prevents the evaporation of water and diffusion of $Zn^{2+}$ ions away from the current collector. Additional functionality was incorporated by replacing some of the gelling agents with new materials. Alcohols with moderate viscosity, namely maltose, sucrose, poly ethylene glycol 600, and 2-hydroxyethyl cellulose, were used to replace some gelling agents in this work. Among these alcohols, poly ethylene glycol 600 and 2-hydroxyethyl cellulose improved the cycle life of full cells. This improved cycle life was attributed to the inhibition of water electrolysis and the improved cycle life of the anode.

• Proceedings of the Korea Concrete Institute Conference
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• 2003.11a
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• pp.497-500
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• 2003

The propose of this study is to discover the extrusion lightweight concrete panel mixing by admixture. The standard of water ratio 50% and weight substitution 0%, 10% by Fly-ash. When the products are manufactured, it is used to maintain its form weight substitution and addition among the viscosity agent each Silica-fume and Hydroxy propyl methyl cellulose. The study is basic properties and performances of extrusion lightweight concrete panels. Testing methods was specific gravity, water absorption, resistance to impact, thermal conductivity, and sound insulation.

• Proceedings of the KACD Conference
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• 2001.11a
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• pp.558.1-558
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• 2001

Flowable resin composite is a relatively new restorative material. It has been reported that a low viscosity, low modulus intermediate resin applied between the bonding agent and restorative resin act as an "elastic buffer" that can relieve contraction stress. This in-vitro study aimed to evaluate the effect of flowable composite resin as a restorative material on regional tensile bond stredgth to cervical wedge shaped cavity walls. (omitted)

• Carbon letters
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• v.13 no.4
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• pp.254-259
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• 2012

Nanoporous non-woven carbon fibers for a gas sensor were prepared from a pitch/polyacrylonitrile (PAN) mixed solution through an electrospinning process and their gas-sensing properties were investigated. In order to create nanoscale pores, magnesium oxide (MgO) powders were added as a pore-forming agent during the mixing of these carbon precursors. The prepared nanoporous carbon fibers derived from the MgO pore-forming agent were characterized by scanning electron microscopy (SEM), $N_2$-adsorption isotherms, and a gas-sensing analysis. The SEM images showed that the MgO powders affected the viscosity of the pitch/PAN solution, which led to the production of beaded fibers. The specific surface area of carbon fibers increased from 2.0 to $763.2m^2/g$ when using this method. The template method therefore improved the porous structure, which allows for more efficient gas adsorption. The sensing ability and the response time for the NO gas adsorption were improved by the increased surface area and micropore fraction. In conclusion, the carbon fibers with high micropore fractions created through the use of MgO as a pore-forming agent exhibited improved NO gas sensitivity.

• The Journal of the Korea Contents Association
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• v.15 no.1
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• pp.324-330
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• 2015

When diagnostic ultrasounds are used, an ultrasonic transmission media is used to effectively transmit the ultrasonic energy. Types of ingredients of polymer hydro gel, emulsion, and oil gel were compared with commercialized products by measuring characteristics of ultrasonic transmission media such as skin lubricity, skin moisturizing, and dryness speed which were contained in each different media. The mean friction coefficient measured to investigate skin lubricity showed high in the agent containing a large amount of oil, whereas the mean friction coefficient of the low viscosity emulsion did not show a significant difference with that of the polymer hydro gel. The moisture evaporation measured to investigate the dryness speed of the agent showed highest in polymer hydro gel. This showed that the larger amount of oil it had, the less moisture evaporation occurred. For skin moisture measured to investigate moisturizing characteristics of skin, low viscosity emulsion showed high in moisture content, whereas it showed slowest reduction in moisture content. As a type of emulsion appropriately containing water and oil is superior in skin moisturizing and skin tenderness, it is expected to serve as a dosage form of new ultrasonic transmission media.

• Journal of the Korean Society for Heat Treatment
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• v.19 no.4
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• pp.200-207
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• 2006

In addition to the basic properties of the base and top coating agents, corrosion resistance of non-chrome magni 565 coating and characteristics of coating film when coated to steel substrate were studied. The system had a good wettability at room temperature. Moreover, both the contact angle and surface tension were affected little by the viscosity of coating agent and surface roughness of the steel substrate. And the samples coated with optimal conditions showed a great corrosion resistance in salt spray test with 1500 hours or longer of initial appearance time of rust. The coating film was composed of overlapping layer of zinc and aluminium flakes, and the thickness of base coat increased with an increase of base coat viscosity. Based on the C-F peaks of 1,1-Difluoroethaen homo-polymer, it was thought that the base coat was an inorganic polymer bond layer. Meanwhile, the top coat showed C-F peaks of polytetrafluoroethylene with C-H peaks of phenol in FT-IR analysis. From the lower weight loss of base coat in TG analysis, it was thought that cross linking density of base coat was larger than that of top coat. It was thought that the small exothermic reactions observed in DSC curves were due to the thermosetting resins contained in the coating agents. Compared to the non-coated specimen, the coated sample showed more higher polarization resistance and corrosion potential with lower corrosion current density.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2000.11a
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• pp.396-402
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• 2000

Porous structures of aluminum foam have been studied. The apparent foam shape, foam hight, density, pore size, shape, and their distributions in various section areas of the experimental samples have been investigated. The sample have been cast into metallic mold, using aluminum foam prepared from a precursor based on pure Al ingot mixed with various amount of 1-2wt% increasing viscosity and foam agent materials. The process provides for flexibility in design of foam structures via relatively easy control over the amount of hydrogen evolution and the drainage processes which occur during foam formation. This is facilitated by manupulating parameters such as the foaming agent, thermal histories during solidification and mix melt viscosities. The acoustical performance of the panel made with the foamed aluminum is considerably improved; its absorption coefficient shows NRC 0.6-0.8. It has been found that the Al foam is very preferable for the compactness of the thermal system.