• Restorative Dentistry and Endodontics
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• v.20 no.1
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• pp.183-192
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• 1995

The purpose of this study was to evaluate the effect of smear layer management on the interfacial morphology between dentin bonding system and dentin. Clearfil New Bond, Scotchbond Multipurpose, Prisma Universal Bond 3 and X-R Bond were used on the cervical dentinal surfaces of bovine incisor teeth. All of the dentin bonding systems were labeled with fluorescene in primer and rhodamine B in adhesive. Specimens of 2~3mm thichness were prepared by longitudinal and labiolingual sectioning. The interface between dentin bonding system and dentin was observed by flouresence imaging with a confocal laser scanning microscope. Following results were obtained. 1. In the specimen of Clearfil New Bond, dentinal tubules were widened by destruction of peritubular dentin in the course of treatment with phosphoric acid of high concentration. 2. Hybrid layer was observed in the specimen of Scotchbond Multipurpose and X-R Bond. 3. In the specimen of Prisma Universal Bond 3, the penetraton of adhesive was not observed clearly.

• Carbon letters
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• v.19
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• pp.32-39
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• 2016

In this work, we studied the effects of electrochemical oxidation treatments of carbon fibers (CFs) on interfacial adhesion between CF and epoxy resin with various current densities. The surface morphologies and properties of the CFs before and after electrochemical-oxidation-treatment were characterized using field emission scanning electron microscopy, atomic force microscopy, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and single-fiber contact angle. The mechanical interfacial shear strength of the CFs/epoxy matrix composites was investigated by using a micro-bond method. From the results, electrochemical oxidation treatment introduced oxygen functional groups and increased roughness on the fiber surface. The mechanical interfacial adhesion strength also showed higher values than that of an untreated CF-reinforced composite.

• International Journal of Concrete Structures and Materials
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• v.1 no.1
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• pp.37-43
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• 2007

This paper discusses the failure mode of reinforced concrete beams strengthened with composite materials based on six experimental set-ups to determine the FRP-to-concrete bond strength. Interfacial bond behavior between concrete and CFRP plates was discussed. Shear test were performed with different concrete compressive strengths (21 MPa and 28 MPa) and different bonding length (100 mm, 150 mm, 200 mm, and 250 mm). Shear test results indicate that the effective bond length (the bond length beyond which the ultimate load does not increase) was estimated as $196{\sim}204\;mm$ through linear regression analysis. Failure mode of specimens occurred due to debonding between concrete and CFRP plates. Maximum bond stress is calculated as about $3.0{\sim}3.3\;MPa$ from the relationships between bond stress and slip. Finally, the interfacial bond-slip model between CFRP plates and concrete, which is governed debonding failure, has been estimated from shear tests. Average bond stress was about $1.86{\sim}2.04\;MPa$, the volume of slip between CFRP plate and concrete was about $1.45{\sim}1.72\;mm$, and the fracture energy was found to be about $1.35{\sim}1.71\;N/mm$.

• Proceedings of the Korea Concrete Institute Conference
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• 1991.04a
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• pp.65-68
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• 1991

Finite element analysis is used to study the role of interfacial properties on the bond strength of reinforcing steel to concrete. Specifically, the role played by epoxy coatings on the failure of standard beam-end specimens is explored. Experimental results show that epoxy coatings reduce bond strength, but that the effect is dependent on the bar size and the deformation pattern. The finite element model for the beam-end specimen includes representations for the deformed steel bar, the concrete, and the interfacial material. The interface elements can be varied to match the stiffness and friction properties of the interfacial material. Cracking within the concrete is represented using Hillerborg's ficticious crack model. The model is used to study important aspects or behavior observed in the tests and to provide an explanation for the effect of the various test parameters.

• Transactions of Materials Processing
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• v.27 no.5
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• pp.267-275
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• 2018

The clad sheet material is produced by a roll-bonding process of one or more materials with different properties. Good formability of clad sheet material is an essential property in to deform a clad metal sheet into a part or component. Performance of the clad sheet material largely depends on interfacial bond strength between different materials. In this study, interfacial bond strength of STS/Al clad sheet was analyzed by varying experimental parameters using a blanking process. Experimental parameters are the punching speed, clearance, and stacking order of plate materials. In addition, blanking test results were compared with bond strengths measured by the T-peel test, that analyzes interface bonding strength of the standard clad sheet. The blanking process was analyzed by the finite element method under the sticking condition of interface of different materials, and experimental results and analysis results were compared.

• Geomechanics and Engineering
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• v.14 no.3
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• pp.233-240
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• 2018

Pullout tests are usually employed to determine the ultimate bearing capacity of reinforced soil, and the load-displacement curve can be obtained easily. This paper presents an analytical solution for predicting the full-range mechanical behavior of a buried planar reinforcement subjected to pullout based on a bi-linear bond-slip model. The full-range behavior consists of three consecutive stages: elastic stage, elastic-plastic stage and debonding stage. For each stage, closed-form solutions for the load-displacement relationship, the interfacial slip distribution, the interfacial shear stress distribution and the axial stress distribution along the planar reinforcement were derived. The ultimate load and the effective bond length were also obtained. Then the analytical model was calibrated and validated against three pullout experimental tests. The predicted load-displacement curves as well as the internal displacement distribution are in closed agreement with test results. Moreover, a parametric study on the effect of anchorage length, reinforcement axial stiffness, interfacial shear stiffness and interfacial shear strength is also presented, providing insights into the pullout behaviour of planar reinforcements of MSE structures.

• Proceedings of the KSME Conference
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• 2001.11a
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• pp.38-43
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• 2001

The interfacial adhesive joining characteristics of the foams are very important for the structural integrity of sandwich structures. Peel strength is one of the best criteria for the interfacial characteristics of the sandwich structures and peel energy is most commonly used for the interfacial characteristics. The peel strength is the first peak force per unit width of bond line required to produce progressive separation by the wedge or other crack opening type action of two adherends where one or both undergo significant bending and the peel energy is the surface active energy per unit width of bond line. In this work, to investigate the strengthening effect of resin treatment on the interfacial surface of foam material, peel strength and peel energy of epoxy resin treated polyurethane foam core sandwich structures were obtained by the cleavage peel tests and compared with those of non surface treated polyurethane foam core sandwich structures.

• The Journal of Korean Academy of Prosthodontics
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• v.30 no.2
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• pp.135-154
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• 1992

This study was performed to analyze bond strength, the alterations of the interfaces between metal films which are populary used and considered to contribute to the chemical reaction with porcelain, according to constant ion- beam- mixing, and the relation between interfacial chemical reactions and bond strength in metal/porcelain specimens. For this study, three seperate metals : selected-gold, indium and tin were chosen ; each to be bonded to a seperate body porcelain. Bonding occurs when the metal is deposited to the body porcelain using a vacuum evaporator. The vacuum evaporator used $10^{-5}\sim10^{-6}$ Torr vacuum states for the evaporation of various metals (Au, Sn, In). Ion-beam-mixing of the porcelain/metal interfaces caused reactions when the Ar+ was implanted into thin films using a 80 KeV accelerator. These ion-beam-mixed specimens were then compared with an unmixed control group. An analysis of bond strength and ionic changes between the the metal and porcelain was performed by electron spectroscopy of chemical analysis (ESCA) and scratch test. The finding led to the following conclusions : 1. Light microscopic views of the scratch test : The ion-beam-mixed Au/porcelain specimen showed narrower scratched streams than the unmixed specimen. However, the Sn/porcelain, In/porcelain specimens showed no differences in the two conditions. 2. Acoustic emissions in scratch tests : The ion-mixed Au/porcelain, In/porcelain specimens showed signals closer to the metal/porcelain interfaces than unmixed specimens. Conversely, the ion-mixed Sn/porcelain specimen showed more critical signals in superficial portions than unmixed specimens. 3. After ion- beam-mixing, the Au/porcelain specimen showed apparently increased bond strength, and the In/porcelain specimen showed very slightly increased bond strength. However, the Sn/porcelain specimen showed no differences between ion mixed specimen and the unmixed one. 4. ESCA analysis : The ion-beam-mixed Au/porcelain specimen showed a higher peak separated value (4.3eV) than that of the unmixed specimen(3.65eV), the ion-beam-mixed In/porcelain specimen showed a higher peak separated value (9.43eV) than that of the unmixed specimen(7.6eV) and the ion-beam-mixed Sn/porcelain specimen showed a higher peak separated value (8.79eV) than that of the unmixed specimen(8.5eV). 5. Interfacial changes were observed in the ion-mixed Au/porcelain, In/porcelain and Sn/porcelain specimens. Especially, significant interfacial changes were measured in the ion- mixed Sn/porcelain specimen. Tin dioxide(SnO2) and a combination of pure tin and tin dioxide (Sn+SnO2) were produced. 6. In the Au/porcelain specimen, the interfacial chemical reaction showed increased bond strength between gold and porcelain substrate. But, in the In/porcelain, Sn/porcelain specimens, interfacial chemical reactions did not affected the bond strength between metal and porcelain substrate. Especially, bonding strength on the ion mixed Sn/porcelain specimen showed the least amount of difference.

• Journal of Industrial Technology
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• v.28 no.A
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• pp.195-198
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• 2008

Graphite and $MoS_2$ were added respectively to the Cu/Sn bond materials of the same composition as a lubricant in order to find out the effect of lubricants on the mechanical properties and the increase in density of the sintered products for microblades. The addition of $MoS_2$ as a lubricant was more beneficial to strength, fracture toughness, and hardness as well as densification than graphite. $MoS_2$ seemed to be more effective in reducing the friction between the metallic powders and die wall during hot pressing process. Due to the better wettability of MoS2 with bond metal alloy, less amount of interfacial defects which is detrimental to mechanical properties use observed.

• Proceedings of the Korea Concrete Institute Conference
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• 2003.05a
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• pp.579-584
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• 2003

For strengthening deteriorated concrete structures, externally bonded FRP sheets or plates using epoxy resins are widely used. For the external FRP composites to be effective in improving the performance of the structure, bond between FRP composites and concrete is required. In general, the most frequently observed failure mode in FRP strengthened concrete structures is debonding failure at the interfacial section between FRP and concrete. Therefore, it is very important to find out the interfacial behavior properties. This paper presents experimental results of the relationship of concrete and FRP sheet for some conditions including concrete compressive strength, concrete surface preparation to observe the bond behavior between concrete and FRP sheet and various anchorage types to increase the bond capacity of FRP sheet.