• Geomechanics and Engineering
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• v.18 no.5
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• pp.555-566
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• 2019

The purpose of this paper is to investigate the thermal effects on the behaviour reinforced-concrete beams strengthened by bonded angle-ply laminated composites laminates plate $[{\pm}{\theta}n/90m]_S$. Effects of number of $90^{\circ}$ layers and number of ${\pm}{\theta}$ layers on the distributions of interfacial stress in concrete beams reinforced with composite plates have also been studied. The present results represent a simple theoretical model to estimate shear and normal stresses. The effects the temperature, mechanical properties of the fibre orientation angle of the outer layers, the number of cross-ply layers, plate length of the strengthened beam region and adhesive layer thickness on the interfacial shear and normal stresses are investigated and discussed.

• Structural Engineering and Mechanics
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• v.78 no.5
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• pp.573-583
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• 2021

This paper presents a theoretical approach of the structures reinforced with bonded FRP composites, taking into account loading model, shear lag effect and the thermal effect. These composites are used, in particular, for rehabilitation of structures by stopping the propagation of the cracks. They improve rigidity and resistance, and prolong their lifespan. In this paper, an original model is presented to predict and to determine the stresses concentration at the FRP end, with the new theory analysis approach. The model is based on equilibrium and deformations compatibility requirements in and all parts of the strengthened beam, i.e., the concrete beam, the FRP plate and the adhesive layer. The theoretical predictions are compared with other existing solutions. The numerical resolution was finalized by taking into account the physical and geometric properties of materials that may play an important role in reducing the stress values. This solution is general in nature and may be applicable to all kinds of materials.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.36 no.5
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• pp.482-487
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• 2023

A carbon-based hybrid resistor was fabricated using carbon nanotube (CNT) paste as an adhesive layer to establish electrically continuous ohmic contacts between CNT sheets and different CNT sheet or copper based metal alloy plates, and its electrical properties were evaluated. CNT sheets were fabricated using vacuum filtration with a CNT solution dispersed in isopropyl alcohol (IPA) solvent. The electrical characteristics of these carbon-based hybrid resistors were investigated. The CNT paste fulfilled the requirements for forming ohmic contacts between CNT sheets and metal alloy plates, which was attributed to the lowest work function difference and excellent wettability at the interface.

• Parasites, Hosts and Diseases
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• v.33 no.3
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• pp.165-172
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• 1995

A transmission electron microscopic study was performed on the ultrastructure of the tegumental layer of GymophoLloines seoi (Digenea: Gymnophallidae) metacercarlae and adults. The metacercariae were obtained from naturally infected oysters, Crcssosoea gigas, and the adults from experimentally infected C3H mice. The tegumental layer generally revealed a small number of foldings, numerous small vacuoles, sines, and muscle bundles. Beneath the muscle layer, nuclei of the tegumental cells were located. There was little difference in the structure of the tegument between the metacercariae and adults. The oral sucker, having well-developed muscle layers, showed a similar structure to the ventral sucker except numerous foldlngs in the ventral sucker. The ventral pit was surrounded by a thin spcpiu layer, where a number of microtubules and mitochondria were seen. Around the ventral pit located well-developed circular and longitudinal muscles. The results showed that the ultrastructure of the tegumental layer of G. seoi metacercariae and adults revealed little difference from other trematodes in general. The ventral pit, a peculiar structure of this trematode, seems to function as a sphincter or an accessory adhesive organ.

• Restorative Dentistry and Endodontics
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• v.21 no.1
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• pp.425-435
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• 1996

The effect of application of dentin bonding agent to the exposed dentin on the intradental nerve activity (INA), dentinal fluid movement and sealing of the dentinal tubules, was investigated in this study. The INA was recorded from the single pulp nerve unit dissected from the inferior alveolar nerve. And specimen of dentin was observed by SEM. Dentinal fluid 'movement through exposed dentin surface was measured before and after the application of dentin bonding agent. 1. Eight Ao-fiber units (conduction velocity: $8.0{\pm}4.0m$/sec) were identified. 4M NaCl evoked an irregular burst of action potentials which ceased immediately after washing. 2. In 4 $A{\delta}$-fiber units, appliction of All Bond 2 completely abolished the INA induced by 4M NaCl. Also, application of Scotchbond Multipurpose(SBMP) totally abolished the INA induced by 4M NaCl in 4 $A{\delta}$-fiber units. 3. Before the application of dentin bonding agent, outward dentinal fluid movement of $10.2{\pm}5.7\;pl{\cdot}s^{-1}{\cdot}mm^{-2}$ was obsered. But after the application of dentin bonding agent the movement of dentinal fluid was stopped. 4. The gap width of 2-$3{\mu}m$ was formed between exposed dentin and adhesive resin in the specimens applied with dentin bonding agents of All Bone 2 and SBMP. But the formation of hybrid layer and the penetration of resin into were dentinal tubules were not clearly observed in interface between dentin and adhesive resin.

• Journal of Conservation Science
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• v.35 no.4
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• pp.295-307
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• 2019

In the process of the conservation treatment of the glass eyes of the stone standing Maitreya of Daejosa temple, Buyeo (Treasure No. 217), a blackish material, expected to be the adhesive for fixing the glass eyes, was collected and analyzed. Infrared spectroscopy and pyrolysis/gas chromatography/mass spectrometry (pyrolysis/GC/MS) were employed to identify the organic material in the sample. The IR analysis revealed the presence of materials such as apatite or bone black. The pyrogram of the sample was similar to that of Asian lacquer, among traditional adhesives. In particular, the pyrolysis/GC/MS analysis with online methylation detected 1,2-dimethoxy-3-pentadecylbenzene, methyl 7-(2,3- dimethoxyphenyl) heptanoate, and methyl 8-(2,3-dimethoxyphenyl)octanoate. These are known to be the pyrolysis products of catechol and its oxidation product, which indicated the presence of Asian lacquer in the sample. X-ray diffraction, X-ray fluorescence, and thermal gravimetry analysis showed that the sample contained ca. 60% inorganic substances, including apatite. Radiocarbon dating of the sample suggested that the blackish material was applied between the late 13^th and early 15^th century, revealing some discrepancy with the art-historical manufacturing time of the Maitreya. From the above analysis, it was concluded that Asian lacquer and bone ash were used to attach the glass eyes by forming a thick blackish lacquer layer.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.2
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• pp.608-613
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• 2010

This study is on development of UV-cured water soluble coating composition which have more improved anti-cigar burning to prevent a surface of PVC tile from damage of heat. To make an anti-cigar burning coating solution, thermostable agent that synthesize main materials phosphorus compound, guanidine and ammonium phosphate dibasic used temporary flame retardants, changing their contents from 10 to 30wt% against quantities of resin and compounded. After coating PVC tiles using bar-coating method that can adjust a thickness, we estimated surface properties of coated layer such as anti-cigar burning, adhesive power, chemical resistance, thickness of coating, and so on. Results showed that a coating composition added 30 wt% of phosphorus compound and coated with No.12 bar-coater had the best optimized surface property in anti-cigar burning effect, adhesive power and chemical resistance. Also, we could find anti-cigar burning effect was improved as thermostable agents content and coating thickness increased.

• Composites Research
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• v.29 no.5
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• pp.249-255
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• 2016

The fiber metal laminates have been widely used at aerospace industry due to outstanding fatigue characteristic, corrosion resistance and impact resistance and so forth. The objective of this research is to establish the proper manufacturing variables for enhancing the interfacial energy release rate of fiber metal laminates using Taguchi method. The major variables of the manufacturing process are surface treatment, pre-specified temperature holding time and additional pressure. In order to determine the interfacial adhesive strength, the double cantilever beam and end-notched flexure tests were conducted. Afterward, Mode I and II energy release rates at various conditions were introduced signal-to-noise ratio with respect to each condition. Finally, the most efficient manufacturing variables are recognized using larger-the-better characteristic.

• Structural Engineering and Mechanics
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• v.61 no.3
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• pp.407-417
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• 2017

RC shear walls are considered one of the main lateral resisting members in buildings. In recent years, FRP has been widely utilized in order to strengthen and retrofit concrete structures. A number of experimental studies used CFRP sheets as an external bracing system for retrofitting of RC shear walls. It has been found that the common mode of failure is the debonding of the CFRP-concrete adhesive material. In this study, behavior of RC shear wall was investigated with three different micro models. The analysis included 2D model using plane stress element, 3D model using shell element and 3D model using solid element. To allow for the debonding mode of failure, the adhesive layer was modeled using cohesive surface-to-surface interaction model at 3D analysis model and node-to-node interaction method using Cartesian elastic-plastic connector element at 2D analysis model. The FE model results are validated comparing the experimental results in the literature. It is shown that the proposed FE model can predict the modes of failure due to debonding of CFRP and behavior of CFRP strengthened RC shear wall reasonably well. Additionally, using 2D plane stress model, many parameters on the behavior of the cohesive surfaces are investigated such as fracture energy, interfacial shear stress, partial bonding, proposed CFRP anchor location and using different bracing of CFRP strips. Using two anchors near end of each diagonal CFRP strips delay the end debonding and increase the ductility for RC shear walls.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.38 no.5
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• pp.521-526
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• 2014

In this study, closed-cell aluminum foam with an initial crack was investigated to produce an axial load-time graph. Using the 10-kN Landmarks of MTS Corporation, a 15-mm/min velocity of mode I shape was applied to the aluminum foam specimen using the displacement control method. ABAQUS 6.10 simulation was used to model and analyze the identical model in three dimensions under conditions identical to those of the experiment. The energy release rate was calculated on the basis of an axial load-displacement graph obtained from the experiment and a transient image of the crack length, and then an FE model was analyzed on the basis of this fracture energy condition. The relation between load and displacement was discussed; it was found that the aluminum foam deformed somewhat less than the adhesive layer owing to the difference in elastic modulus.