• Proceedings of the Korean Society of Precision Engineering Conference
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• 1996.11a
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• pp.908-912
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• 1996

FRMLs consist of thin sheets of high strength metal, which are laminated using a structural adhesive and high strength fibers. ARALL(Aramid-fiber Reinforced Aluminum alloy Laminates) of FRMLs is a new class of hybrid material. HERALL(Heracron Reinforced Aluminum Laminate) i.e. domestic ARALL is made of homemade aramid fibers, adhesives and adhesive technique. Domestic aramid fiber is Heracron manufactured by KOLON and domestic adhesive is epoxy resin manufactured by Han Kuk Fiber. In this study, Fatigue crack propagation behavior was examined in a 2024-T3 aluminum alloy/aramid-fiber epoxy 3/2 laminated composites, HERALL and ARAL $L^{ⓡ}$-2 LAMINATE comparing with 2024-T3 aluminum alloy. The extrinsic toughening mechanisms in HERALL and ARALL were examined, the crack bridging behavior of fibers was analyzed by new algorithm, which measures crack bridging stress, and the crack bridging zone length was measured.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 1993.10a
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• pp.97-102
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• 1993

The application of epxy composite materials for the outdoor insulating systems has some significant advan-tages compared with conventional inorganic materials, that is low weight in combination with high mechanical strength, small dimensions and design versatility. The paper describes the results of high voltage investigations carried out different aging types of epoxy resin insulator and silicone grease coating. The insulators have been exposed 3000 hours to weather-o-meter and 12 months to outdoor. In this connection, the main study of paper is form the basis of develop-ment of principal technologies of epoxy composites which ard: (1)manufacturing of insulator, (2)high vol-tage testing under dry and wet condition, (3)mechani-cal properties, (4)accelerated weather-ometer test and outdoor exposed, artificial polution.

• Textile Coloration and Finishing
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• v.19 no.4
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• pp.26-31
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• 2007

Nanocomposite resin(PUD-CNT) composed of Carbon nanotube(CNT) and Polyurethane Dispersion (PUD) was prepared by different contents of CNT($0{\sim}5%$). PUD-CNT was coated on samples, and their electrical conductivity was investigated. With increasing CNT content, static change, half life and surface resistance decreased. Composites having 5% CNT showed $10^9{\Omega}/cm$(surface resistance), and 40V (stactic charge). Respectively, From this results, PUD-CNT can be used as a antistatic material.

• Carbon letters
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• v.15 no.1
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• pp.67-70
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• 2014

In this work, nanocomposites of epoxy resin and chemically reduced graphene oxide (RGO) were prepared by thermal curing process. X-ray diffractions confirmed the microstructural properties of RGO. Differential scanning calorimetry was used to evaluate the curing behaviors of RGO/epoxy nanocomposites with different RGO loading amounts. We investigated the effect of RGO loading amounts on the mechanical properties of the epoxy nanocomposites. It was found that the presence of RGO improved both flexural strength and modulus of the epoxy nanocomposites till the RGO loading reached 0.4 wt%, and then decreased. The optimum loading achieved about 24.5 and 25.7% improvements, respectively, compared to the neat-epoxy composites. The observed mechanical reinforcement might be an enhancement of mechanical interlocking between the epoxy matrix and RGO due to the unique planar structures.

• Carbon letters
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• v.8 no.1
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• pp.17-24
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• 2007

Microporous carbons with narrow pore size distribution have been successfully synthesized by using hydrolyzed and calcined silica as templates and phenol formaldehyde (pf) resin as carbon precursor. Phenol formaldehyde-silica micro composites were prepared by solution route. Subsesequently, silica templates were removed by HF leaching. Resulting carbons were steam activated. The porous carbons were characterized by nitrogen adsorption-desorption isotherm, SEM, FTIR analysis, iodine adsorption, thermogravimetry analysis, etc. Adsorption isotherms show that the porous carbon prepared from calcined silica as templates are microporous with 88% pores of size <2 nm porosity and are of type I isotherm, while porous carbon prepared by using hydrolyzed silica are microporous with 89% microporosity, shows hysteresis loop at high relative pressure indicating the presence of some mesoporosity in samples. The microporosity in porous carbon materials has a bearing on the nature of silica templates used for pore formation.

• Korean Journal of Materials Research
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• v.8 no.5
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• pp.429-435
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• 1998

무정형 PEEK 필름의 self-bonding 공정 시에 일어나는 결정화 현상이 접합 면에서 개발되어지는 self-bonding 강도에 미치는 영향을 주사전자현미경(SEM)을 이용하여 고찰하였다. 무정형 PEEK 필름의 결정화 현상은 접합 시의 공정변수에 따라 변화하며, self-bonding 공정 동안 접합 면을 가로질러 PEEK의 결정들이 성장함에 따라 접합이 일어남을 알 수 있었다. 접합온도가 높을수록 접합 면을 가로지르는 결정들의 성장 정도가 낮은 온도에서 접합시켰을 때의 경우보다 훨씬 커서 결과적으로 높은 self-bonding 강도를 보였다. 각각의 시편들을 전단 파괴시킨 후 행한 파단면 관찰에서는 self-bonding 강도가 점차 높아짐에 따라 더욱 조밀한 물결무늬 파면과 dimple 형태와 유사한 파면 형상들이 관찰되는 것으로 보아 접합공정 시 접합 면을 가로지르는 PEEK 결정들의 성장 정도가 self-bonding 강도에 커다란 영향을 미친다고 판단되었다.

• Proceedings of the KIEE Conference
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• 1994.07b
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• pp.1323-1326
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• 1994

the application of epoxy composite materials for outdoor insulating systems has some significant advantages compared with conventional inorganic materials, that is low weight in combination with high mechanical strength, small dimensions and design versatility. The experimental results for the basis composition and interlace characteristics of the matrix resin/inorganic fillers($SiO_2$) which are the composite materials have been studied. The electrical characteristics(electrical breakdown, dielectric, insulating resistivity, tracking) and mechanical characteristics( tensile strength, elongation, flexible strength) in the epoxy composite materials have been studied. The life of the epoxy composite material was evaluated by accelerated Weather-Ometer test and the degradation process due to outdoor exposure condition is discussed with respect to the mechanical and electrical properties.

• Proceedings of the KIEE Conference
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• 1994.07b
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• pp.1357-1359
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• 1994

In this study, in order to improve the problem that dielectric breakdown strength decrease remarkably at high temperature, simultaneous interpenetrating polymer networks method was Introduced so that epoxy insulating material could have stable temperature characteristics and stable dielectric breakdown characteristics at whole temperature range. So network structure of epoxy/$SiO_2$ composite material was changed by adding MA and MA/PU into epoxy resin. DC voltage is applied into the specimen fabricated by this method, and then the result was compared and investigated.

• Composites Research
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• v.17 no.2
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• pp.21-27
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• 2004

In this paper, the polymer concrete using the chemically treated waste paint and polystyrene foam was manufactured and their mechanical properties were evaluated. The compressive strength, specific gravity and water absorption with respect to the volume percents of the waste paint and resin were tested. From the tests, the specific gravities of the polymer concretes using the waste paint were lower than that of the conventional polymer concrete and it was recommended that they can be used for building exterior materials.

• Journal of the Korean Society for Railway
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• v.9 no.1 s.32
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• pp.57-62
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• 2006

Composite thin-walled members for civil engineering application are mainly produced by pultrusion technique, and they are generally made of a polymeric resin system reinforced by E-glass fibers due to economical reason. This material combination results in low elastic moduli of the composite materials and makes the design of composite members to be governed by stability limit state. Therefore the buckling behavior of composite thin-walled members was experimentally investigated in the present study. Axial compression was applied on each specimens by a hydraulic ram and knife edge fixtures were placed at both ends to simulate simple boundary condition. Axial compression, lateral displacements and twisting at the mid-height of each specimen were measured by a set of transducers during buckling test. The experimental buckling loads were compared with analytical results obtained through isotropic formulas. In the calculation of analytical results, elastic properties such as Young's modulus(E) and shear modulus(G) were replaced with EL and GLT obtained from coupon tests, respectively.