• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2001.06a
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• pp.127-134
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• 2001

Nano adhesion and friction between a Sj$_3$N$_4$ AFM tip and thin silver films were experimentally studied. Tests were performed to measure the nano adhesion and friction in both AFM(atomic force microscope) and LFM(lateral force microscope) modes in various ranges of normal load. Thin silver films deposited by IBAD (ion beam assisted deposition) on Si-wafer (100) and Si-wafer of different surface roughness were used. Results showed that nano adhesion and friction decreased as the surface roughness increased. When the Si surfaces were coated by pure silver, the adhesion and friction decreased. But the adhesion and friction were not affected by the thickness of IBAD silver coating. As the normal force increased, the adhesion forces of bare Si-wafer and IBAD silver coating film remained constant, but the friction forces increased linearly. Test results suggested that the friction was mainly governed by the adhesion as long as the normal load was low.

• Applied Chemistry for Engineering
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• v.20 no.3
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• pp.251-257
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• 2009

Recently, there is much interest in the antimicrobial activity of silver since silver has known to be safe and effective as a disinfectant or an antimicrobial agent against a broad spectrum of microorganisms. Although silver has been applied to various kinds of products due to the effective antimicrobial activity, the quantitative antimicrobial activity or detailed mechanism of silver is not clearly investigated yet, causing the controversy and confusion. In this review paper, we summarized the characteristics, antimicrobial activities and mechanisms, synergistic effects with other antimicrobials, and applicability of silver.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2018.06a
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• pp.101-101
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• 2018

Quantitative measurement of chloride ion concentration has an important role in various fields of electrochemistry, medical science, biology, metallurgy, architecture, etc. Among them, its importance of architecture is ever-growing due to unexpected degradations of building structure. These situations are caused by corrosion of reinforced concrete (RC) structure of buildings. And chloride ions are the most powerful factors of RC structure corrosion. Therefore, precise inspection of chloride ion concentration must be required to increase the accuracy of durability monitoring. Multi-walled Carbon nanotubes (MWCNTs) have high chemical resistivity, large surface area and superior electrical property. Thus, it is suitable for the channels of electrical signals made by the sensor. Silver nanoparticles were added to giving the sensing property. CuBTC, one of the metal organic frameworks (MOFs), was employed as a material to improve the sensing property because of its hydrophilicity and high surface area to volume ratio. In this study, sensing element was synthesized by various chemical reaction procedures. At first, MWCNTs were functionalized with a mixture of sulfuric acid and nitric acid because of enhancement of solubility in solution and surface activation. And functionalized MWCNTs, silver nanoparticles, and CuBTC were synthesized on PTFE membrane, one by one. Electroless deposition process was performed to deposit the silver nanoparticles. CuBTC was produced by room temperature synthesis. Surface morphology and composition analysis were characterized by scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDS), respectively. X-ray photoelectron spectroscopy (XPS) was also performed to confirm the existence of sensing materials. The electrical properties of sensor were measured by semiconductor analyzer. The chloride ion sensing characteristics were confirmed with the variation of the resistance at 1 V.

• The Journal of Korean Academy of Prosthodontics
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• v.58 no.4
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• pp.275-281
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• 2020

Purpose: Development of a latent antimicrobial soft liner is strongly needed to overcome a possible inflammation related with its dimensional degrade or surface roughness. Modified tissue conditioner (TC) containing chitosan-doped silver nanoparticles (ChSN) complexes were synthesized and assessed for their characterizations. Materials and methods: ChSN were preliminarily synthesized from silver nitrate (AgNO₃), sodium borohydride (NaBH₄) as a reducing agent and chitosan biopolymer as a capping agent. Ultraviolet-visible and Fourier transform infrared spectroscopy were conducted to confirm the stable reduction of nanoparticles with chitosan. Modified TC blended with ChSN by 0 (control), 1.0, 3.0 and 5.0 % mass fraction were mechanically tested by ultimate tensile strength (UTS), silver ion elution and color stability (n=7). Results: At 24 hour and 7 day storage periods, UTS values were not significant (P>.05) as compared with pristine TC (control) and silver ion was detected with the dose-dependent values of ChSN incorporated. Color stability of TC were influenced by ChSN add, with the higher doses, the significantly greater color changes (P<.05). Conclusion: A stable synthesized ChSN was acquired and modified TC loading ChSN was characterized as silver ion releasing without detrimental physical property. For its clinical application, antimicrobial test, color control and multifactor investigations are still required.

• Bulletin of the Korean Chemical Society
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• v.35 no.5
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• pp.1541-1544
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• 2014

• Proceedings of the PSK Conference
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• 2003.04a
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• pp.227.1-227.1
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• 2003

To assess the effect of chitosan complex with metal ion on various pathogenic bacteria, the antibacterial activities were investigated. Arsenic, bismuth, calcium, iodine, iron, mercury, platinum, and silver were used as a metal ion. Staphylococcus aureus. Streptococcus mutans, Helicobacter pylori, Propionibacterium acnes and human saliva were examined. It was demonstrated that metal ions associated chitosan showed aggregation activities on various pathogens.

• Bulletin of the Korean Chemical Society
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• v.17 no.5
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• pp.405-407
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• 1996

• Bulletin of the Korean Chemical Society
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• v.12 no.5
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• pp.465-467
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• 1991

• Bulletin of the Korean Chemical Society
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• v.20 no.4
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• pp.487-490
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• 1999

• Journal of the Korean Applied Science and Technology
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• v.19 no.3
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• pp.222-244
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• 2002

A mixture of methyl ester derivatives of fatty acids from the oils of pine nuts was well resolved to five fractions differing by degree of unsaturation by silver ion solid-phase extraction column chromatography ($Ag^{+}$-SEC). Polyunsaturated fatty acid with non-methylene interrupted conjugated double bond (NMiDB) radical held more strongly to silver ions in the column than methylene interrupted conjugated double bond (MiDB) one when they had the same number of double bonds. Although both the picolinyl ester and DMOX derivative provided clear mass ion species powerful enough to elucidate the structure of the polyunsaturated fatty acid (PUFA) with NMiDB and/or methylene interrupted conjugated double bond (MiDB) radical in the oils, the picolinyl ester of PUFA with NMiDB radical did not provide a cluster of mass ions neighboring diagnostic mass ions induced by the double bond in the proximal to the carboxyl group. However, the DMOX derivative of PUFA with NMiDB group as well as MiDB showed abundant mass ion species differing by gaps of 12 amu, which made it possible with greater ease to locate the double bonds in the molecule. The oil contained $C_{18:2{\omega}6}$ (46.2 %) and $C_{18:1{\omega}9}$ (25.4 %) as main components, and considerable amounts of PUFAs with NMiDB radical such as ${\Delta}^{5.\;9.\;12}-C_{18:3}$ (16.0 %), ${\Delta}^{5.\;9}-C_{18:2}$ (2.3 %) and ${\Delta}^{5.\;11.\;14}-C_{20:3}$ (0.8 %).