• Food Science of Animal Resources
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• v.26 no.4
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• pp.497-502
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• 2006

The adhesion of 16 bifidobacterial strains, including 10 isolates from Korea infants, to Caco-2 cells and their cell surface hydrophobicity were tested. The results of adhesion and cell surface hydrophobicity of for various bifidobacterial strains were obtained and correlations between adhesion and hydrophobicity were strain-dependent properties. Any correlations between species of tested strains were not observed. Among the tested strains, Bifidobacterim longum D6, B. longum H4, B. thermophilum ATCC 25525, B. suis ATCC 27533, and B. animalis subsp. lactis BB12 had higher adherent properties and B. bifidum B3, B. longum D6, B. longum stronger hydrophobicity, respectively. Due to the strain-dependant correlation between adhesion to Caco-2 cells and cell surface hydrophobicity of bifidobacteria, these results provide a possible method for preliminary selection of bifidobacteria potentially adherent to Caco-2 cells by means of cell surface hydrophobic properties.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.08a
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• pp.275-275
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• 2013

Osteoblast is one of cells related with osseointegration and many research have conducted the adhesion of osteoblast onto the surface of implant. In the osseointegration, biocompatibility of the implant and cell adhesion to the surface are important factors. The researches related to cell adhesion have a direction from micro-scaled surface roughness to nano-scaled surface roughness with advancing nanotechnology. A cell reacts and sense to stimuli from extracellular matrix (ECM) and topography of the ECM [1]. Thus, for better osseointegration, we should provide an environment similar to ECM. In this study, we synthesize TiO2 nanowires using hydrothermal reaction because TiO2 provides inertness to titanium on its surface and enables it used as an implant material for the orthopedic treatment such as fixation of the bone fracture [2]. Ti substrate is immersed into NaOH aqueous solution. The solution are heated at $140{\sim}200^{\circ}C$ for various time (10~720 minutes). After heat treatment, we take out the sample and immerse it into HCl aqueous solution for 1 hour. The acid treated sample is heated again at $500^{\circ}C$ for 3 hours [3]. Then, we culture osteoblast on the TiO2 nanowires. For investigating cell adhesion onto nanostructured surface, we conduct several tests such as MTT assay, ALP (Alkaline phosphatase) activity assay, measuring calcium expression, and so on. These preliminary results of the cell culture on the nanowires are foundation for investigating cell-material interaction especially with nanostructure interaction.

• Corrosion Science and Technology
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• v.4 no.6
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• pp.222-225
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• 2005

The adhesion strength of metal plating on PC was studied. In this study, surface was treated by chemical agents or DBD(dielectric barrier discharge) plasma to imporve the adhesion. The surface roughness, contact angle, gloss of plating and adhesive strength were measured. Adhesion strengths of Ni plating on prepared PC by NaOH and KOH solution were $12.3kgf/cm^2$ and $7.5kgf/cm^2$, respectively. The highest adhesion strength was obtained in the plasma treated one, $27.8kgf/cm^2$.

• Journal of the Korean Society for Nondestructive Testing
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• v.29 no.6
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• pp.534-549
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• 2009

As the thin film technology has emerged in various fields, adhesion of the film interface becomes an important issue in terms of the longevity and durability of thin film devices. Diverse nondestructive methods utilizing acoustic techniques have been developed to assess the interfacial integrity. As an effective technique based on the ultrasonic wave focusing and the surface acoustic wave(SAW) generation, scanning acoustic microscopy(SAM) has been investigated for adhesion evaluation. Visualization of film microstructures and quantification of adhesion weakness levels by SAW dispersion are the recent achievements of SAM. To overcome the limitations in the theoretical dispersion model only suitable for perfectly elastic and isotropic materials, a new model has been more recently developed in consideration of film anisotropy and viscoelasticity and applied to the adhesion evaluation of polymeric films fabricated on semiconductive wafers.

• Korean Journal of Materials Research
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• v.15 no.1
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• pp.6-13
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• 2005

Copper based leadframe sheets were immersed in two kinds of hot alkaline solutions to form brown-oxide or blackoxide layer on the surface. The oxide-coated leadframe sheets were molded with epoxy molding compound (EMC). After post mold curing, the oxide-coated EMC-leadframe joints were machined to form sandwiched double-cantilever beam (SDCB) specimens. The SDCB specimens were used to measure the fracture toughness of the EMC/leadframe interfaces under quasi-Mode I loading conditions. After fracture toughness testing, the fracture surface were analyzed by various equipment to investigate failure path. An adhesion model was suggested to explain the failure path formation. The adhesion model is based on the strengthening mechanism of fiber-reinforced composite. The present paper deals with the introduction of the adhesion model. The explanation of the failure path with the proposed adhesion model was introduced in the companion paper.

• Journal of the Korean institute of surface engineering
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• v.29 no.3
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• pp.157-162
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• 1996

The effects of microstructural change on the adhesion strength between Cu/Cr film and polyimide have been studied. Cr films (50 nm thick) and Cu films (500 or 1000 nm thick) were deposited on polyimide by DC magnetron sputtering. During Cu deposition the Ar pressure was 5 or 100 mtorr. The microstructure was observed by SEM and the adhesion was measured by T-peel test. Plastic deformation of peeled metal strips was characterized quantitatively by using XRD technique. The film in which Cu is deposited at 100 mtorr has higher adhesion strength than the film in which Cu is deposited at 5 mtorr. And in the film with same deposition pressure of 100 mtorr, the adhesion strength is increased as the deposited thickness increases from 500 to 1000 nm. The adhesion change of Cu/Cr can be interpreted as the difference in plastic deformation.

• Journal of the Korean institute of surface engineering
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• v.53 no.6
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• pp.306-311
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• 2020

In this work, diamond-like carbon (DLC) films are coated onto plasma nitrided AISI 4140 steel by DC-pulsed PECVD. One problem of DLC films is their very poor adhesion on steel substrates. The purpose of the nitriding was to enhance adhesion between the substrate and the DLC films. The white layer formation is avoided. Plasma nitriding increased adhesion from 8 N for DLC coating to 25 N for duplex coating. Duplex plasma nitriding/DLC coating was proven to be more effective in improving the adhesion. The purpose of the bond layer was to enhance adhesion between the substrate and the DLC films.

• Tribology and Lubricants
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• v.18 no.4
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• pp.267-272
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• 2002

Nano adhesion between SPM(scanning probe microscope) tips and DDPO$_4$(octadecylphosphoric acid ester.) and ODPO$_4$(octadecylphosphoric acid ester) SAM(self-assembled monolayer.) was experimentally studied. Tests were performed to measure the nano adhesion and friction in both AFM(atomic force microscope) and LFM(lateral force microscope) modes with the applied normal load. DDPO$_4$ and ODPO$_4$ SAM were formed on Ti and TiOx surfaces. Ti and TiOx were coated on the Si wafer by ion sputtering. Adhesion and friction of DDPO$_4$ and ODPO$_4$ SAM surfaces were compared with those of OTS(octadecyltrichlorosilane) SAM and DLC surfaces. DDPO$_4$ and ODPO$_4$ SAM converted the Ti and TiOx surfaces to be hydrophobic. When the surface was hydrophobic, the adhesion and friction forces were found lower than those of bare surfaces. Work of adhesion was also discussed to explain how the surface was converted into hydrophobic Results also showed that tribological characteristics of DDPO$_4$ and ODPO$_4$ SAM had good properties in the adhesion, friction, wetting angle and work of adhesion. DDPO$_4$ and ODPO$_4$ SAM could be one of the candidates for the bio-MEMS elements.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.28 no.8 s.227
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• pp.1087-1092
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• 2004

Adhesion and friction forces influence adversely on performance and durability of MEMS. It has been reported that the adhesion and friction forces can be reduced with the introduction of micro surface bumps into the contacting interfaces. In this study experiments were conducted to investigate comparatively the effect of hemispherical and torus micro bumps on the adhesion and friction forces. It is confirmed that micro bumps reduce the adhesion and friction forces, and their effect is more pronounced with the bumps of smaller outer boundary radius. Moreover, the results shows that the torus bumps exhibit more rapid decrease of the adhesion and friction forces with the decrease in the outer boundary radius of bump than the hemispherical bumps. When the magnitude of adhesion force is same, the torus bumps generate smaller friction force than the hemispherical bumps. The usage of hemispherical and torus bumps to reduce the adhesion and friction forces in MEMS is discussed.

• Journal of the Korean institute of surface engineering
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• v.26 no.6
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• pp.316-326
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• 1993

Adhesion and hardeness are the most important properties of a hard coated layer which is applied to wear-resistant devices. Zr/ZrN layer was deposited on tool steel(SKH9) and stainless steel(SUS304) by a re-active D.C. magnetron sputtering technique and their microhardness and adhesion strength were measured for the films processed by changing the partial pressures of $N_2$ gas (4~10$\times$$10^{-4}$mbar) and the substrate bias voltage(0~250V). The adhesion strength was evaluated by acoustic signals through the scratch-test with the incremental applied load. As the partial pressure of $N_2$ gas and the substrate bias voltage were increased, the adhesion strength of tool steel was observed to be stronger than that of the stainless steel. The adhesion strength was generally, observed to decrease with the same tendency regardless of the kinds of substrates. The adhesion strength of tool steel was increased more and more strongly than that of stainless steel as heat-treated temperature was increased. The strength of tool steel was appeared to be high adhesion strength at $400^{\circ}C$. From the failure mode of the film during the scratch adhesion test, the cohesive failure was observed to be obvious and the adhesive failure in a minor portion in the Zr/ZrN doublelayer regardless of the kinds of substrates.