• 한국농공학회논문집
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• 제54권5호
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• pp.9-16
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• 2012

In this study, the effect of metakaoline and silica fume on the bond performances of structural polyvinyl alcohol (PVA) fiber in cement mortar, including bond strength, interface toughness, and microstructure analysis are presented. Metakaoline and silica fume contents ranging from 0 % to 15 % are used in the mix proportions. Pullout tests are conducted to measure the bond performance of PVA fiber from cement mortar. Test results showed the incorporation of metakaoline and silica fume can effectively enhance the PVA fiber-cement mortar interfacial properties. Bond strength and interface toughness increased with metakaoline and silica fume content up to 10 % in cement mortar and decreased when the metakaoline and silica fume content reached 15 %. The microstructural observation confirms the findings on the interface bond mechanism drawn from the fiber pullout test results.

• Journal of information and communication convergence engineering
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• 제8권4호
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• pp.399-404
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• 2010

We propose a seamless IPTV transport technology of mobile device. This technology uses multiple interfaces of wireless communication on mobile device. This proposal for transportation of mobile IPTV contents is more mobile and adaptable than other wireless technologies that are currently being used. Algorithm of proposed technology is as follow. When the signal strength of the connected wireless network interface of mobile device is getting lower than specified level, another wireless network interface is connected to continue downloading the IPTV contents in advance. Another connection is maintained until the signal strength of the first connected interface is stable or the interface is connected to another base station (or AP) that have good signal strength. For more seamless services, we consider classifying the packets of mobile IPTV and using dynamic content quality select techniques. Dynamic content quality selection is based on notifying transfer rate to the content delivery network (CDN) server. The proposed technology is expected to use efficiently with both mobile IPTV and the transportation of mobile P2P/P4P.

• 한국지반공학회논문집
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• 제18권1호
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• pp.79-89
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• 2002

폐기물 매립지에는 차수 및 보호기능을 하는 다양한 토목섬유가 사용된다. 토목섬유 사이의 접촉(interface) 전단강도는 사면에 설치되는 차수 및 최종 덮개시설의 안전한 설계를 위해 곡 필요한 물성치로서, 본 연구에서는 대형 직접전단 시험기를 사용하여 지오멤브레인(GM)과 지오텍스타일(GT) 사이의 접촉 전단강도를 측정하였다. 본 논문에서는 Mohr-Coulomb 파괴 포락선을 이용하여 전단강도를 평가하였으며, 연직하중, 수팀상태, 지오멤브레인(GM)의 표면상태-texturing 유무 - 등이 전단강도에 미치는 영향을 알아보았다. 분석 결과 연직하중이나 수침상태가 전단강도에 미치는 영향은 각각 하중의 크기와 토목섬유의 종류에 따라 정도가 다르게 나타났다. 사면에 설치되는 토목섬유의 경우, 다양한 현장조건-상재하중, 수침상태, 사용되는 토목섬유의 종류을 고려한 시험 결과를 통해 얻은 물성치를 이용하여야 안전한 설계가 될 수 있을 것이다.

• 한국도로학회논문집
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• 제18권5호
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• pp.1-9
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• 2016

PURPOSES : This study focuses on the evaluation of interface performance with varying surface texture and tack coat application in an asphalt overlay. METHODS : The evaluation is carried out in two phases: tracking test and interface bond strength test. Using an image processing tool, tracking test is conducted to evaluate the susceptibility of the tack coat material to produce excessive tracking during application. Using the pull-off test method, the bond strength test is performed to determine the ability of the interface layer to resist failure. RESULTS : Results show that the underseal application yields less tracking compared to other applications. However, the bond strength is barely within the minimum acceptable value. On the other hand, RSC-4 produces higher bond strength for all surface types, but the drying time is long, which produces excessive tracking. CONCLUSIONS : While underseal application may be suitable for a trackless condition, the bond strength is less appealing compared to the rest of the tack applications available. RSC-4 demonstrated a high and consistent bond strength performance, but more time is required for drying to avoid excessive tracking. Tack coat application and surface type combination produce varying results. Therefore, these should be considered when selecting suitable future tack coat application options.

• 한국기계가공학회지
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• 제12권2호
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• pp.62-67
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• 2013

The influence of internal stress and joint strength(shear, tensile) according to the deposition conditions was investigated by the Polyimide substrate and ZnO thin film. Deposition thickness and temperature affect the internal stress and the internal stress was minimum at the 60nm and $200^{\circ}C$ of the deposition conditions. Tensile strength is large at the deposition condition that shear strength is large and the shear strength was about 50% of the tensile strength. The shear strength and tensile strength were large at deposition condition that internal stress was small. Crack occurred near the joint interface of Polyimide substrate and progressed along the interface until the final fracture.

• Journal of Welding and Joining
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• 제4권2호
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• pp.47-52
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• 1986

Friction Welds are formed by the mechanisms of diffusion as well as mechanical inter-locking. The severe plastic flow at the interface by the forge action of the process brings the subsurface so close together that detection of any unbounded area becomes very difficult. No reliable method is available so fat to determine the weld quality nondestructively. The paper presents an attempt to determine weld strength quantitatively using the ultrasonic pulseecho method. The new approach calculates the coefficient of reflection based on measured amplitudes of the echoes. This coefficient provides a single quantitative measurement which involves both acoustic energy reflected at the welded interface as well as transmitted across the interface. As a result, it was known that the quantitative relationship between the coefficient and the weld strength (torsional strength) could be drawn.

• Computers and Concrete
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• 제20권3호
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• pp.291-295
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• 2017

Tests on the fracture behavior of CFRP-concrete composite bonded interfaces have been extensively carried out. In this study, a progressive damage model is employed to simulate the fracture behaviors. The crack nucleation, propagation and more other details can be captured by these models. The numerical results indicate the fracture patterns seem to depend on the relative magnitudes of the interface cohesive strength and concrete tensile strength. The fracture pattern transits from the predominated adhesive-concrete interface debonding to the dominated concrete cohesive cracking as the interface cohesive strength changes from lower than concrete tensile strength to higher than that. The numerical results have an agreement with the experimental results.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1998년도 봄 학술발표회 논문집(I)
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• pp.359-364
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• 1998

The interfacial zone in concrete materials is extensive, geometrically complex, and constitutes inherently weak zones that limit the concrete performance. Motar-aggregate interfaces play a major role in the fracture processing in concrete composites. Also, the interfacial bond considerably influence mechanical properties of concrete such as modulus of elasticity, strength, and fracture energy, Characterization of the interfacial properties is, therefore, essential to overcome the limitations associated with the interfaces. an objective of this paper is to investigate the corelationship between the fracture toughness of mortar-aggregate interface and the concrete properties such as strengths and elastic moduli. It is observed from the test results that interface fracture toughness is closely related with the compressive strength rather than other properties. At early ages, the development of both tensile strength and elastic modulus are much greater thatn that of both interface fracture toughness and compressive strength.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 춘계학술대회 논문집
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• pp.1018-1021
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• 2003

A scratch tester was developed to evaluate the adhesive strength at interface between thin film and substrate(silicon wafer). Under force control, the scratch tester can measure the normal and the horizontal forces simultaneously as the probe tip of the equipment approaches to the interface between thin film and substrate of wafer. The capacity of each component of force sensor is 0.1 N ∼ 100 N. In addition, the tester can detect the signal of elastic wave from AE sensor(frequency range of 900 kHz) attached to the probe tip and evaluate the bonding strength of interface. Using the developed scratch tester. the feasibility test was performed to evaluate the adhesive strength of semiconductor wafer.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 추계학술대회
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• pp.1448-1452
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• 2003

A scratch tester was developed to evaluate the adhesive strength at interface between thin-film and substrate(silicon wafer). Under force control, the scratch tester can measure the normal and the tangential forces simultaneously as the probe tip of the equipment approaches to the interface between thin-film and substrate of wafer. The capacity of each component of force sensor is 0.1 N ${\sim}$ 100 N. In addition, the tester can detect the signal of elastic wave from AE sensor(frequency range of 900 kHz) attached to the probe tip and evaluate the bonding strength of interface. Using the developed scratch tester, the feasibility test was performed to evaluate the adhesive strength of thin-film.