• Composites Research
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• v.29 no.5
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• pp.282-287
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• 2016

p-DCPD (poly dicyclopentadiene) is the resin that the versatile mechanical properties can be changeable via the control of inner monomer and catalysts. In this work, to improve the strength of composites, surface treated MGF (milled glass fiber) was used as an reinforcement in p-DCPD by molybdenum (Mo) catalyst matrix. The optimum concentration of surface treatment was obtained and the cohesion of MGF themselves increased with concentration. In case of 0.2 wt% silane concentration, the maximized mechanical properties of MGF/p-DCPD composite exhibited because of minimized MGF cohesion. When butyl silane showing minimizing cohesion was used as the optimized alkyl length, high tensile and flexure strength exhibited due to the steric hindrance effect among MGFs. Mechanical and their fractured surfaces of MGF/p-DCPD composites was compared for 4 different chemical functional groups. Norbornene functional groups containing similar chemical structure to DCPD matrix exhibited higher interfacial adhesion between MGFs and DCPD matrix.

• Journal of the Korean Society for Marine Environment & Energy
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• v.16 no.1
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• pp.53-59
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• 2013

Since 1990s, the major recycling methods for mechanical recycling of FRP(Fiber Reinforced Plastics)boats has involved shredding and grinding of the scrap FRP in a new recycled product. But still it leads to secondary problem such as air pollution, unacceptable shredding noise level and few limited applications. This study is to propose a newly advanced method which is more efficient and environment friendly waste FRP regenerating system. As extracting FRP layer and making the recycled fiber for recycled-fiber reinforced concrete(RFRC) from waste FRP, the recycling process has some merits in a sense of the recycling energy and the environmental effects. In this study, for those tasks, spectro-chemical differentiation method and coloring water-soluble dye treatment makes the roving layer more distinguishable photophysically. Also that has remarkably reduced safety hazards and energy. Using the mechanical properties of polymers and composite, FRP with the orthotropic and laminated plastic structure has been easily separated in the new extracting system. Also the new method has introduced five kind of separating manuals for the some different compositions of FRP boats. The roving fiber of laminated glass-fiber layer is as good as the polyvinyl fiber which is cost-high commercial fiber to increasing strength of concrete products. The early study has shown the effectiveness of laminated glass-fiber layer which also is chemical-resistant due to the resin coating. These results imply that more efficient and environment friendly recycled glass fiber can be better applied to the fiber reinforced concrete(FRC) substitute and this study also has shown wide concrete applications with RFRC from the waste FRP boat.

• Journal of the Korean Ceramic Society
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• v.39 no.2
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• pp.171-177
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• 2002

In this study, the vertical aligned carbon nanotubes was synthesized by DC bias-assisted Inductively Coupled Plasma Hot-Filament Chemical Vapor Deposition (ICPHFCVD). The substrate used CNTs growth was Ni(300 ${\AA}$)/Cr(200 ${\AA}$)-deposited one on glass by RF magnetron sputtering. R-F, DC bias and filament power during the growth process were 150 W, 80 W, 7∼8 A, respectively. The grown CNTs showed hollow structure and multi-wall CNTs. The top of grown CNT was found to Ni-tip that the CNT end showed to metaltip. The graphitization and field emission properties of grown was better than grown CNTs by ICPCVD. The turn-on voltage of CNT grown by DC bias-assisted ICPHFCVD showed about 3 V/${\mu}m$.

• Journal of the Korean Institute of Gas
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• v.7 no.1 s.18
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• pp.28-32
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• 2003

In order to apply the properties of fiber reinforced plastic(FRP) to support panel of polyurethane foam in LNG storage tank, we estimated the mechanical properties, degree of vapour barrier, chemical stability and thermal conductivity changes as ageing. According to the results, the mechanical strength (i.g. compressive strength, bending strength, tensile strength and shear strength) are more than 30 times higher than those of plywood. The FRP-polyurethane foam(PUF) composites have lower thermal conductivity changes as ageing than plywood-PUF composites. FRP-PUF sandwich composite for LNG storage tank with these remarkable properties are compared the abilities of these structures with those of the conventional structures(plywood-PUF sandwich composite). Finally, we can obtain the effects such as superior mechanical properties and fuel saving through improved ability of vapor barrier.

• Applied Chemistry for Engineering
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• v.24 no.5
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• pp.499-506
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• 2013

As the usuage of tempered glass for touch panel increased rapidly with the development of industry, the amount of UV curable coating solution used to protect glass surfaces during a tempered glass manufacturing process increased as well. The UV curable coating has advantages compared to thermal curing such as shortened curing time and non-solvent. Appropriated polymer and monomer were used as an acid polymer to grant an alkali peeling ability. The monomers were 2-hydroxyl methylacrylate, 1,6-hexanediol diacrylate and dipentaerythritol hexaacrylate which have acryl groups of 1, 2, and 6, respectively. The combination of three different types of photoinhibitors were used and bisphenol A epoxy diacrylate was used as an oligomer. In this study, experiments were carried out by controlling the amount of photoinitiator, oligomer, and additive while maintaining the constant content of the acid polymer and the acrylic monomer. The changes in physical properties according to the additive content were investigated. It was found that the combination of photoinitiators was necessary to achieve the hardness above 4H and it was possible to control the delamination type of the coating film from a sheet to pieces by the addition of TPO as an initiator. The increase in oligomer contents increased the hardness and adhesiveness alongside dissection time. Talc content of 20 wt% showed the best results.

• Journal of Adhesion and Interface
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• v.22 no.4
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• pp.118-127
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• 2021

In this study, the mechanical properties of vulcanized rubber were evaluated through compounding by controlling filler content to improve the mechanical properties of NBR rubber. Aramid and glass fibers with excellent heat resistance were used as fillers, and ceramics were additionally used in anticipation of a complementary effect, and as for the ceramic materials, needle-shaped and plate-shaped ceramics were used. Each filler was used in an amount of 5.0, 10.0, 15.0, and 20.0 phr in order to investigate the basic properties according to the amount of filler. To confirm the complementary effect through ceramic application, each 10.0 phr fiber and ceramic were mixed with 1:1 ratio to evaluate mechanical properties. As a result, it was confirmed that the decreasing ratio of tensile strength after heat aging was small in the order of aramid fiber, acicular ceramic, glass fiber, and plate ceramic in the case of applying the filler alone. In addition, the mechanical characteristics of vulcanized rubber using composite filler based on fibers and ceramics were evaluated, and it was confirmed that the composite filler had a complementary effect on thermal aging.

• Journal of Conservation Science
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• v.33 no.1
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• pp.25-33
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• 2017

The stone lantern of the four guardian kings in the Beopjusa temple at Boeun was mainly made of biotite granodiorite consisting of porphyritic-textured potassium feldspar and included in ilmenite series. A base stone made of alkali granite was buried, after founded its place during an earlier restoration process. Cracking and break out are noticeable on this object. In addition, discoloration, salt crusting, and epiphytes were observed. The lantern was vulnerable in terms of physical and structural stability caused by cracking in the front and back of the light chamber and in the non-horizontal direction. According to the conservational condition of the stone lantern, structural reinforcement was carried out based on calculations, including those on the position, size, and anchor length of the titanium stiffener. Chemical and biological pollutants were washed off without damage to the surface of the stone material. Oxygenated iron pieces were replaced with titanium. Ethyl silicate was applied to the surface of the lantern for consolidation and smooth drainage.

• Journal of the Korean Chemical Society
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• v.37 no.3
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• pp.327-333
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• 1993

A method was developed for the determination of trace elements in seawater by precipitate flotation preconcentration and subsequent flame atomic absorption detection. In order to quantitatively coprecipitate trace ions such as Cd(II), CuI(II), Fe(III), Mn(II), Pb(II) and Pd(II), 2.0 ml of 1.0M cerium(III) solution was added to 1.0l of seawater and the pH was adjusted to 9.5 with 5.0 M sodium hydroxide solution while stirring with a magnetic stirrer. The precipitate was floated with the aid of surfactant solution (1.0 ml of 0.3% sodium oleate) by bubbling nitrogen gas through a porous (No. 4) fritted glass disk. The floats was collected in a small Erlenmeyer flask by suction. The washed precipitate was dissolved in 8.0 M nitric acid and marked with deionized water in the volumetric flask of 10.0 ml. The analyte was determined by measuring the atomic absorbances in 100-fold concentrated solution. Above all analytes in Kangnung (East Sea) and Kanghwado (West Sea) sea waters were found to be under the detection limit of this method. The recoveries of over 92% for all analytes spiked into seawater samples showed that this method was applicable to the analysis of real seawater.

• Korean journal of food and cookery science
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• v.26 no.6
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• pp.872-886
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• 2010

Six kinds of sunsik containing different contents of brown rice(BR; 20, 30, and 50%) were prepared and subjected to various processing conditions(with or without roasting at $200^{\circ}C$ for 20 min e.g., designated as RBR50 or BR50) to assess their functionality as ready-to-eat foods. They were also assessed for their nutritional and sensory properties and oxidative stability. Dietary fiber contents were proportionate to the levels of added BR. Protein was highest in RBR50 (p<0.001), which also had the highest amounts of free and structural amino acids. The amount of free amino acids tended to increase with roasting, although most amino acids were present in structural form. Oleic acid and linoleic acid were the predominant fatty acids in all prepared sunsik, and RBR50 presented noticeably higher peroxidability index due to its higher amount of linoleic acid(p<0.05). Nevertheless, RBR50 showed good oxidative stability; this phenomenon was observed in all sunsik with roasted BR but not in those with non-roasted BR. It is implied that potential antioxidants might have been newly formed or converted from their precursors while BR was roasted. Roasting process also had an impact on the sensory properties of sunsik, e.g., sunsik with added roasted BR showed lower dissolution and darker color intensity compared to its counterpart sunsik.

• Journal of Korean Society of Forest Science
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• v.87 no.1
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• pp.106-112
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• 1998

This study was conducted to figure out the relationships among soil chemical properties and bacterial biomass related to denitrification and sulfur-reducing and the activity of dehydrogenase, and ultimately to consider the usefulness of dehydrogenase activity as a tool for evaluating the dynamics of forest soil ecosystem. Four sites were selected for the collection of soil samples within two regions(Onsan industrial estate as a polluted region and Mt. Mani at Kanghwa island as a clean area) with two forest types (coniferous and deciduous stands). The soils of Mt. Mani showed higher amount of organic matter, total nitrogen and available phosphorus than those collected from Onsan industrial estate, which indicated that the soils were more beneficial for microbial growth than those of Onsan. The dehydrogenase activity was more sensitive than the denitrifying bacteria or sulfur-reducing bacteria since the activity was significantly different between the regions and season while the two bacterial biomass were not significantly different between the two regions. In addition, the dehydrogenase activity showed relatively high correlation coefficients with organic matter(r=0.53, p=0.004), total nitrogen(r=0.41, p=0.008) and C/Ava. P-ratio(r=-0.52, p=0.001), which was thought to be closely related with microbial activity. Thus, the dehydrogenase activity was thought to be a useful index of soil ecosystem dynamics with considering that the technique need to be applied with the same soil texture for the comparison of the activity as other researchers indicated.