• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.11a
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• pp.170-171
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• 2006

The chemical shift of SiOC film was observed according to the flow rate ratio. SiOC film has the broad main band of $880{\sim}1190cm^{-1}$ and the sharp Si-$CH_3$ bond at $1252cm^{-1}$, and the infrared spectra in the Si-O-C bond moved to low frequency according to the increasing of an oxygen flow rate. The chemical shift affected the carbon content in the SiOC film, and the decreasing of carbon atoms elongated the C-H bonding length, relatively. The main bond without the sharp Si-$CH_3$ bond at $1252cm^{-1}$ consisted of Si-C, C-O and Si-O bonds, and became the bonding structure of the Si-O-C bond.

• Journal of Welding and Joining
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• v.15 no.2
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• pp.43-53
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• 1997

The complete joining method for dissimilar press punch materials and its real-time evaluation method is not available at present. Brazing method has been used for joining them, but it is known that the welded joint by the brazing has the lower bonding efficiency and reliability than the diffusion welding. The friction welding with a diffusion mechanism in bonding was applied in this study. This work was carried out to determine the proper friction welding conditions and to analyze mechanical properties of friction welded joints of sintered carbide tool materials (SKNM50 for the blade part of press punch) to alloy steel (SCM440 for the shank part of press punch) using aluminum (A6061 for the interlayer material) as an insert material between the sintered carbide tool materials and the alloy steel. In addition, acoustic emission test was carried out during friction welding to evaluate the weld quality.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2011.04a
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• pp.282-284
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• 2011

Based on graphene oxide and multi-walled carbon nanotube layers, a wireless bi-layer actuator that can be remotely controlled with an electromagnetic induction system has been developed. The graphene-based bi-layer actuator exhibits a large one-way bending deformation under eddy current stimuli due to asymmetrical responses originating from the temperature difference of the two different carbon layers. In order to validate one-way bending actuation, the coefficients of thermal expansion of carbon nanotube and graphene oxide are mathematically formulated in this study based on the atomic bonding energy related to the bonding length. The newly designed graphene-based bi-layer actuator is highly sensitive to electromagnetic wave irradiation thus it can trigger a new actuation mode for the realization of remotely controllable actuators and is expected to have potential applications in various wireless systems.

• Journal of the Microelectronics and Packaging Society
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• v.8 no.3
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• pp.25-30
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• 2001

The stress intensity factors for edge cracks located at the bonding interface between the semiconductor chip and the adhesive layer subjected to a uniform transverse tensile strain are investigated. Such cracks might be generated due to a stress singularity in the vicinity of the free surface. The boundary element method (BEM) is employed to investigate the behavior of interface stresses. The amplitude of complex stress intensity factor depends on the crack length, but it has a constant value at large crack lengths. The rapid propagation of interface crack is expected if the transverse tensile strain reaches a critical value.

• Proceedings of the Korea Concrete Institute Conference
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• 2005.05a
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• pp.287-290
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• 2005

CFRP strips manufactured in factory are produced normally with smaller width and larger thickness than CFRP sheets. By this reason, bonding force between CFRP strips and concrete substrate is not sufficient to sustain tensile force in CFRP strips. Therefore premature debonding failure cannot be avoided when strengthening is done by simply bonding the CFRP strips. The flexural strength of RC beam strengthened with CFRP strips must be calculated based on the effective strain considering debonding failure. This paper presents test results of an experimental study conducted to evaluate the flexural strength on RC beams strengthened with CFRP strips. 7 specimens were tested with respect to bond length and amount of CFRP strips. From the test results, it was indicated that the strain of the CFRP strips achieved at debonding failure can be decreased less than 6,000$\mu$ depending on the amount of CFRP strips.

• Journal of the Korean GEO-environmental Society
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• v.15 no.8
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• pp.31-37
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• 2014

In this study, mechanical properties of Very-Rapid Hardening Polymer (VRHP) mortar were investigated. To do it, 75 VRHP mortar specimens were tested by the compressive test, bending test, bonding test, freezing and thawing test, length variation test, and water absorption test. From the test results, it was confirmed that the bond strength of VRHP was higher than that of normal concrete by 50 %, and the resistance of freezing and thawing of VRHP was more excellent than normal concrete. In addition, length variation ratio and water absorption ratio of VRHP were smaller than those of normal concrete by 20 %. Therefore, It should be mentioned that VRHP can be successfully used as the material for repairing the crack of concrete structure.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.37 no.8
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• pp.751-758
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• 2009

Failure strengths of composite single-lap adhesive joints were investigated with various parameters such as manufacturing method, overlap length and adherend thickness. A total of 335 single-lap joint specimens were tested under tension. Specimens were fabricated with 4 different manufacturing processes; cocuring without and with adhesive, secondary bonding and co-bonding. Each manufacturing process has 5 different overlap lengths and 4 different thicknesses, respectively. As expected, failure strength is higher in thicker adherend joints and lower in larger overlap length specimens. Interesting result is that the secondary bonded joints show the higher strength than the cobonded and cocured joints with adhesive, and give close or even higher strength compared with non-adhesive cocured case.

• Restorative Dentistry and Endodontics
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• v.24 no.1
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• pp.55-66
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• 1999

The purpose of this study was to evaluate the microleakage of 5 current dentin bonding systems which are composed of 2 multi-bottle systems(Scotchbond Multi-Purpose, All Bond2) and 3 one-bottle systems(Single bond, One-Step, Prime & Bond). In this in vitro study, class V cavities were prepared on buccal and lingual surfaces of sixty extracted human premolars and molars on cementum margin. The experimental teeth were randomly divided into six groups of 10 samples (20 surfaces) each, Group 1 : Scotchbond Multi-Purpose ; Group 2 : All Bond 2 ; Group 3 : Single Bond ; Group 4 : One-Step ; Group 5 : Prime & Bond ; Group 6 : no bonding agent(control). The bonding agent and composite resin were applied for each group following the manufacturer's instructions. After 500 thermocycling between $5^{\circ}C$ and $55^{\circ}C$, the 60 teeth were placed in 2% Methylene blue dye for 24 hours, then rinsed with tab water. The specimen were embedded in clear resin, then sectioned buccolingually through the center of restoration with a low speed diamond saw. The dye penetration on each of the specimen were then observed with a stereomicroscope at ${\times}20$. The results of study were statistically analyzed using the Student-Newmann-Keul's Methods and the Mann-Whitney Rank Sum Test. The resin/dentin interfaces were examined under Scanning Electron Microscopy. The results of this study were as follows. 1. None of the dentin bonding systems used in this study showed significant difference in leakage values at both the enamel and the dentin margins (P>0.05). 2. In all groups except the control, leakage value seen at the enamel margin was significantly lower than that seen at the dentin margin (P<0.05). 3. Compared to the control group, all the groups treated with dentin bonding systems showed significantly lower leakage value at both enamel and dentin margins (P<0.05). 4. In the SEM view, gaps were observed in the composite resin / dentin interface in group 6 where no dentin bonding agent was used, and in all the other groups (group 1, 2, 3, 4, 5) composite resin, hybrid layer, and dentin were seen to be closely adhering to each other where there were no leakages. Well-developed resin tags 3~100${\mu}m$ in length infiltrated dentinal tubules past the hybrid layer and a hybrid layer 1~5${\mu}m$ thick had developed between the dentinal surface and the composite resin surface.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.808-812
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• 2003

We need a lot of manpower and we can cut down a labor cost by applying industrial robots the footwear bonding automation process. In this study, we suggest how to program off-line robot path along a shoe's outsole shape in the footwear bonding process by 5-axis microscribe system like robot arms. This microscribe system development consists 5-axis microscribe mechanics, signal processing circuit, and PC with software. It is the system for making database of a shoe's outsole through the movement of a microscribe with many joints. To do this, first read 5-encoders' pulse values while a robot arm points a shoe's outsole shape from the initial status. Then, calculate a relative shoe's outsole by Denavit-Hatenberg's (D-H) direct Kinematics of known length of links and coordinate values. Next, calculate the encoders' pulse values of the robot arm's rotation and transmitting the angle pulse values to the PC through a circuit. Finally, it is able to display a shoe's outsole at real-time by computing the Denvavit-Hantenberg's (D-H) direct kinematics in the PC. With the coordinate values calculated above, we can draw a bonding gauge-line on the upper. Also, we can make off-line robot path programming compute a shoe's bonding area on the upper. These results will be effectively applied for programming a robot path on off-line and automatically.

• Composites Research
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• v.26 no.6
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• pp.386-391
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• 2013

In this paper, a carbon fiber/epoxy composite-aluminum hybrid wheel for passenger cars was suggested for better performance and a prototype was fabricated and tested. Adhesive bonding between aluminum part and a composite rim part was used, and the bonding length and thickness were determined by finite element analysis. For self alignment and the function of bonding jig the special structure with a groove and a protrusion was applied. To evaluate the performance of the hybrid wheel various FE analyses were carried out. Inner and outer molds were prepared for the composite rim part and the thermoformed composite part was bonded to the aluminum part. Vibration tests revealed that the hybrid wheel had 16% higher resonance frequency and 32% higher damping capacity with 10% weight reduction.