• Transactions of the Korean Society of Mechanical Engineers A
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• v.30 no.2 s.245
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• pp.135-140
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• 2006

In tapping mode atomic force microscopy (TM-AFM), the vibro-contact response of a resonating tip is used to measure the nanoscale topology and other properties of a sample surface. However, the nonlinear tipsurface interactions can affect the tip response and destabilize the tapping mode control. Especially it is difficult to obtain a good scanned image of high adhesion surfaces such as polymers and biomolecules using conventional tapping mode control. In this study, theoretical and experimental investigations are made on the nonlinear dynamics and control of TM-AFM. Also we report the surface adhesion is an additional important parameter to determine the control stability of TM-AFM. In addition, we proved that it was adequate to use Johnson-Kendall-Roberts (JKR) contact model to obtain a reasonable tapping response in AFM for the soft and high adhesion samples.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2018.05a
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• pp.283-284
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• 2018

The rear side surface of tiles act have protrusions that helps secure the adhesion between the tile and the mortar for tile setting. Conventional height of the rear side usually ranges between 1 to 1.5 mm, and the molding method is classified in between press type and compression type during the manufacturing process, with most tiles being produced by the former method. In sites where adhesion failures were observed, tiles were taken to examine the cause of defect. It was determined that height was irregular at the rear side surface. Based on these findings, an experiment was conducted to determine the correlation between the rear surface and the bonding strength of tiles.

• Journal of the Korean institute of surface engineering
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• v.30 no.5
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• pp.298-309
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• 1997

Hard Tin coating on tool steel substrate were prepared using the pulsed PACVE. An orthogonal experimental design was employed to find the best deposition conditions for TiN coating and to systematically understand the effect of processing parameters. The small size Taguchi matrix called the L16 was used for experiment and ANOVA(ANalysis of VAriance) was followed to study the effect of main parameters on hardness and adhesion TiN coatings. In conclusion, pulse on/off time ratio and pulsing frequency were the major deposition parameters to determine hardness and adhesion of TiN coating in the pulsed DC PACVE process. (200) preferred orientation, columnar growth and dome-shaped surface morphology of the TiN films gave rise to a high hardness and a good adhesion to the substrates.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1999.05a
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• pp.226-229
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• 1999

Epoxy compound has been used as insulation material in electrical equipment for a long time because of its excellent electrical, mechanical and chemical properties. Nowdays, becoming higher voltage system, the properties of interface between epoxy and metal insert become more important. The breakdown voltage of epoxy compound for electric material is variable according to the surface roughness of metal insert. Generally, with metal insert sanding, the adhesion strength is enhanced and the breakdown strength is reduced. But in this study, we knew that the adhesion strength became enhanced but the breakdown strength didn\`t reduced with metal insert sanding. So in this study sanding. So in this study, we suggest the optimum interface condition by adjusting the surface roughness.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2003.10a
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• pp.59-59
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• 2003

In recent, various functional coatings on artificial tooth implants have been conducted to enhance the bonding strength between implants and bones. Despite of these efforts, some previous reports argued that an adhesion strength between titanium implant and the final coatings like hydroxyapatite(HA) is weaker than the strength between coating and bone. In order to increase the adhesion force between the final coating and implant surface, TiN/DLC based functionally graded coating, which has higher mechanical strength than the titanium implant, was applied as a middle layer between titanium implant and final coating. Particularly we finally coated a biocompatible hydroxyapatite film on the DLC layer and examined the mechanical properties. As a result, TiN/DLC based functionally graded coating showed the higher adhesion strength compared with hydroxyapatite single layer coating on the titanium implant.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2007.11a
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• pp.140-141
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• 2007

The arc ion plating (AIP) technique has been used widely for thin coating in the area of surface engineering. The TiN coating is important in the field of dies, cutting tools and other mechanical parts. When forming the TiN films by AIP technique, the processing parameters such as arc power, bias voltage, working pressure, temperature of substrate and pre-treatment affected the adhesion respectively. The results of scratch test revealed that the adhesion strength was influenced by arc power most strongly. And a sequence of the importance of each parameters has been obtained. The crystal structure and cross-section of TiN films are also be investigated.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.07a
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• pp.232-233
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• 2005

The Surface of semi-conductive silicone rubber was treated by oxygen plasma to improve adhesion and electric performance in joints between insulating and semi-conductive silicone materials. Surface characterizations were assessed using contact angle measurement and Fourier transform infrared spectroscope (FTIR). Adhesion level was understood from T-peel tests between plasma treated semi-conductive and insulating material. Electrical breakdown strength was measured to understand the charge of electrical performance. From the results, the oxygen plasma treatment produces a significant increase in function group of containing oxygen which can be mainly ascribed to the creation of carbonyl groups on the silicone surface from the strength were improved. Therefore it is concluded then plasma treatment leads to decrease voids originating form poor adhesive, and the improve the adhesion in silicone interface. So we could obtain higher electrical design level of silicone material used for electrical apparatus using oxygen plasma treatment.

• Proceedings of the Polymer Society of Korea Conference
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• 2006.10a
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• pp.363-363
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• 2006

Bonding of composite materials with an adhesive layer is one of the most promising alternatives to classical bonding techniques. The use of several surface treatments may greatly increase this adhesion behavior at the initial state. Then in order to see the influence of the thickness of polymer matrix on the adhesion of composite assembly, different surface treatment, which can reduce or increase this thickness, are used (peel ply, tear ply, excimer laser). The influence of this specific parameter is not only discussed at the initial state but also after thermal ageing of the whole bonded assembly. Results show that the best performances at the initial state are not obviously the best performances after ageing.

• Applied Chemistry for Engineering
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• v.2 no.2
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• pp.175-184
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• 1991

Ultraviolet curable coatings are often used to protect the surface of polymer materials exposed to the ultraviolet radiation. However, the adhesion of epoxy acrylate on poly(vinyl chloride) and the UV curable coating on polystyren are poor. The objective of this work was to improve the adhesion of coating according to various formulations of the reactive diluents and finishing methods using the photografting of multifunctional acrylate and the surface activation on polymer surface impregnated a phtoinitiator. The addition of Tripropylene glycole diacrlate in the formulation of coating results in the improvement of adhesion of coating due to the flexibility. But the increase of the crosslinking density which results from the oxidation of surface during the exposure of UV radiation caused the loss of adhesion of coating exept the photografting method. In the trimethylolpropane triacrylate the improvement of adhesion are considerable due to the chemical bond between multifundtional acrylate and surface. From this work we expect to achieve the varity and functionality in the formulation of coating according to the photografting and surface activating of polymer.

• Journal of Microbiology and Biotechnology
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• v.13 no.2
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• pp.276-281
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• 2003

The adhesion of probiotic bacteria to the intestinal mucosa is one of the desirable properties for their colonization in the intestinal tract, where these bacteria constantly compete with other bacteria. The adhesion of different strains of bifidobacteria to Caco-2 cells was compared. Among the strains examined, BGN-4 showed the highest adhesion level and the greatest cell surface hydrophobicity (CSH). No close relationship was found between the adhesion and CSH of the strains. Upon protease and heat treatment, the adhesion of the BGN-4 to the Caco-2 cells decreased significantly. The cells grown at $42^{\circ}C$ showed a lower CSH and self-aggregation levels than cells grown at $37^{\circ}C$. The treatment of EGTA did not have any effect on the adhesion. The degree of adhesion did not differ among the experimental groups in which galactose, mannose, or fucose were added in the adhesion assay mixture. The results suggest that the adhesion of the Bifidobacterium to the epithelial cells may be affected by the composition and structure of the cell membrane and interacting surfaces.