• Journal of the Korean Society for Precision Engineering
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• v.15 no.9
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• pp.68-74
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• 1998

The ESPI(Electronic Speckle Pattern Interferometry) is a real time, full-field, non-destructive optical measurement technique that allows static and dynamic deformation analysis and surface shape measurements of engineering structures. e .g. turbine blades. vehicle engine components, body panels, etc. This technique is very similar to holographic interferometry, but uses a solid static camera and an image processing board for recording and digital processing of speckle patterns. In this paper it is presented that FEM results for the free vibration of symmetrically laminated composite as [30/-30/90]s. The natural frequencies of laminated composite rectangular plates having the particular boundary condition are experimentally obtained. In order to demonstrate the validity of the experiment, FEM analysis using ANSYS was performed and natural frequencies experimentally obtained is compared with calculation by FEM analysis. The results obtained from both experiment and FEM analysis show a good agreement.

• Composites Research
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• v.25 no.5
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• pp.154-158
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• 2012

The effect of structure on the sound absorption and sound transmission loss of composite sheet was investigated. A sheet of polypropylene was bonded by hot press with nonwoven fabric sheets of polyethylene terephthalate on the top side and the back side. Absorption coefficient of composite sheet using nonwoven fabric with surface density of $0.64kg/m^2$ was 0.1-0.2. It is 100-400% improvement compare to that of polypropylene sheet. The transmission loss of composite sheet was increased with surface density of polypropylene board and introduction of hemisphere hole on the surface of sheet. Two types of composite sheet were made using flat sheet and sine wave shaped sheet and the effect of sheet structure on the transmission loss was investigated.

• Journal of the Korean Wood Science and Technology
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• v.43 no.4
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• pp.511-517
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• 2015

Sound absorption capability of the flame resistant treated sawdust-mandarin peel composite particleboard was were estimated by two microphone transfer function methods. The weight of flame resistant treated board slightly increased by the treatment. The treatment improved fire retardant performance by decreasing the charred area of flame resistant treated board. Sound absorption capabilities of flame resistant treated sawdust-mandarin peel composite particleboard, in the entire estimated frequency range of 500-6,400 Hz was slightly lower than those of the control specimen. Sound absorption capability of both the control and flame resistant treated sawdust-mandarin peel composite particleboards were higher than that of commercial gypsum boards, being widely used as a sound absorber for ceiling at the estimated frequency.

• Journal of Korean Society of Steel Construction
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• v.14 no.2
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• pp.357-364
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• 2002

The study performed a series of flexural tests on Closed Cold-Formed Steel Sections for stud, joist, and roof truss. Results were compared with analytical values. Each 2.4-m long and 0.9-m wide specimen consisted of two steel beams set at 0.46 m interval. The steel beams were attached to the specimens using either plaster board or ply wood. Another specimens did not use any attachment material. Positive and negative bending tests were conducted to investigate the composite behavior, including the effects of plaster board or ply wood on the buckling behavior of steel beam. Full-scale roof truss tests were also performed to study the buckling behavior and failure mode of the truss members.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.17 no.2
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• pp.110-113
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• 2008

Embedded capacitor technology is one of the effective packing technologies for further miniaturization and higher performance of electric packaging system. In this paper, the embedded capacitors were simulated and fabricated in 8-layered printed circuit board employing standard PCB processes. The composites of barium titanante($BaTiO_3$) powder and epoxy resin were employed for the dielectric materials in embedded capacitors. Theoretical considerations regarding the embedded capacitors have been paid to understand the frequency dependent impedance behavior. Frequency dependent impedance of simulated and fabricated embedded capacitors was investigated. Fabricated embedded capacitors have lower self resonance frequency values than that of the simulated embedded capacitors due to the increased parasitic inductance values. Frequency dependent capacitances of fabricated embedded capacitors were well matched with those of simulated embedded capacitors from the 100MHz to 10GHz range. Quality factor of 20 was observed and simulated at 2GHz range in the 10 pF embedded capacitors. Temperature dependent capacitance of fabricated embedded capacitors was presented.

• Journal of the Korean Wood Science and Technology
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• v.35 no.6
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• pp.108-117
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• 2007

This research was performed to investigate the feasibility of bamboo as a raw material for the manufacture of plywood. Wood veneer-bamboo zephyr composite boards (WBCB) were manufactured using keruing (Dipterocarpus sp.) veneers and hachiku bamboo (Phyllostacbys nigra var. henonis Stapf) using various adhesives, and the effect of the method and amount of resin spread on the mechanical properties of the composites were investigated. The WBCB manufactured using polymeric isocyanate (PMDI) showed the best mechanical properties, followed by phenol-formaldehyde resin (PF), phenol-melamine-formaldehyde resin, urea-melamine-formaldehyde resin, and urea-formaldehyde resin. However, considering the operation feasibility as well as mechanical properties, PF resin proved to be the appropriate adhesive for the practical purpose. As the amount of resin spread increased, the mechanical properties of 5-ply WBCB with 12 mm thicknesses manufactured using PF resin tended to increase, and more failure occurred at the interface between veneer and bamboo zephyr than at the interface among bamboo zephyrs. This result suggests that penetration of resin into bamboo zephyr could be the important factor. In this research, the appropriate amount of resin amount was $320g/m^2$. 5-ply WBCBs were manufactured using various methods of resin spread but the effect of the methods on the mechanical properties showed no little difference, which meant that the method of resin spread could be chosen considering the manufacturing conditions and operation feasibility.

• Fire Science and Engineering
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• v.32 no.3
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• pp.27-34
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• 2018

A Semi-Incombustible Composite Insulation Board (SICIB) that can be applied to building construction and ships was developed. The SICIBs comprised of pine leaf powder, vermiculite. The incombustibility, semi-incombustibility, and U-factor of the developed SICIBs were measured. The incombustibility of the each SICIB was determined by the proportion of combustible flexible binder and pine leaf powder. SICIB satisfied the incombustibility test without a combustible flexible binder and pine leaf powder. In addition, SICIB with 6% of pine leaf ensured its semi-incombustible performance. A combustible flexible binder or pine leaf powder over 6% failed the fire-resistant performance of SICIB. In addition, SICIBs with incombustible/semi-incombustible finishing and a 200 mm insulating layer (glass wool and sprayed poly urethane foam) met the U-factor of an external wall for buildings described in the Korean building code.

• Journal of the Korea Institute of Building Construction
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• v.21 no.5
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• pp.507-518
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• 2021

The application of an adhesive calcium carbonate-based hybrid insulation board with quasi-combustibility in the external thermal insulation composite system(ETICS) ensures effective thermal performance and fire safety. This study aimed to conduct a mechanical test of the quasi-non-combustible hybrid insulation board as well as its constituent materials to obtain the basic data for the structural design of the adhesive ETICS. Test specimens were fabricated based on domestic and foreign test standards to examine and evaluate their tensile, compressive, flexural, and shear strengths. The strength characteristics of the quasi-non-combustible hybrid insulation board were identified from the test results, which verified that the minimum required physical properties suggested by the current KS M ISO 4898 were met. Furthermore, the quasi-non-combustible ETICS used in this study was found to be suitable for use as an external insulation system for walls unless subjected to continuous gravity load, such as a heavy exterior finish.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2005.11a
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• pp.239-242
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• 2005

This paper introduced an approach of improvement of performance of Electric device for EMU type Train like as TTX. The electric equipments are characterized by insulation, Noise, cooling system etc. and Their weight arc decided by these factors. There are two kinds of power source in EMU train. First, DC voltage source, 1500 volt, 750 volt is used for subway system. Second, AC power source 25000 volt is applied to high speed train and existing main lines. Composite material has the protection of inrush current and high frequency noise. We can use this material to minimize weight of train. Additionally we can get energy saving when operator service TTX.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.06a
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• pp.217-218
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• 2007

Aluminum 분말과 고분자를 혼합하여 고분자-금속 복합재료(polymer-metal composite)를 만들어 copper foil과 기판의 접착력을 평가하였다. Tape casting 방법을 이용하여 sheet 만들고 vacuum lamination으로 PCB(Printed Circuit Board)기판을 제조한 후 포토공정으로 peel strength pattern을 형성하였으며, 본 연구에서는 최적의 aluminum 조건을 찾기 위하여 압력, 온도, copper foil의 표면 상태와 silane 표면 코팅에 따른 aluminum-polymer복합재료의 peel strength의 변화를 확인하였다. 최적의 조건은 silane 표면 코팅 처리를 한 aluminum 분말로 $210^{\circ}C$에서 $9.7kg/cm^2$ 압력으로 matte면의 돌기 크기가 크며, 응집이 잘 되어있는 copper foil을 사용하여 13.89N의 우수한 peel strength를 구현 할 수 있었다.