• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1998년도 추계학술대회 논문집
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• pp.227-230
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• 1998

The interfacial breakdown between two internal dielectric surfaces represents one of the major causes of failure for power cable joint. In order to better understand this phenomenon, breakdown experiments were performed for each interfacial condition at Epoxt/EPDM interface found in cable. The specimen were Epoxy resin and EPDM generally used in cable joint. The interface conditions were three parts. First condition was the pressure of interface, we used the value of 1, 2, 3, 4, 5[kg/cm$^2$]. For the second condition, the sanding condition was treated with sand paper #220, #600, #1200. Finally, we observed the breakdown according to the presence of silicon oil at the interface.

• Macromolecular Research
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• 제17권12호
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• pp.987-994
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• 2009

Palladium nanoparticles having cubic silsesquioxanes (POSS) (Pd-POSS) were produced by the reaction of palladium (II) acetate and octa(3-aminopropyl)octasilsesquioxane octahydrochloride (POSS-${NH_3}^+$ in methanol at room temperature. Functionalized multiwalled carbon nanotubes (MWNT-COOH) were prepared by acid treatment of pristine MWNTs. The hybrid nanocomposites of Pd-POSS and MWNT-COOH (Pd-MWNT nanocomposites) were synthesized by self-assembly method via ionic interaction between positively charged Pd-POSS and negatively charged MWNT-$COO^-$. The spherical aggregates of Pd-POSS with a diameter of 40-60 urn were well attached to the surfaces of MWNT-COOH on Silicon wafer. The composition, structure, and surface morphology of Pd-MWNT nanocomposites were studied by UV-vis spectrophotometer, energy dispersive spectrum (EDX), scanning electron microscopy (SEM), and atomic force microscope (AFM).

• Tribology and Lubricants
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• 제19권5호
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• pp.245-250
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• 2003

Water is known to playa crucial role on friction of moving parts in nanoscale contact. Little is, however, known about the tribological behavior of a solid surface that is covered with water adsorption layer. The objective of this study is to investigate the nanotribological behavior of the water layer in relation to water affinity of the surface and relative humidity. This paper presents an examination of the frictional behavior of water adsorption layer as 'confined liquid film'. It is shown that the friction is inversely proportional to the hydrophilicity of surface and relative humidity. On the other hand, friction of hydrophobic surface is not influenced by relative humidity. A model is proposed for the water-mediated contact in which it is shown that the water layer between two hydrophilic surfaces with high relative humidity behaves as a lubricant.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 춘계학술대회
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• pp.1043-1047
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• 2003

With the advancement of micro-systems and nanotechnology, the need for ultra-precision fabrication techniques has been steadily increasing. In this paper, a novel nano-structure fabrication process that is based on the fundamental understanding of nano-scale tribological interaction is introduced. The process, which is called Mechano-Chemical Scanning Probe Lithography (MC-SPL), has two steps, namely, mechanical scribing for the removal of a resist layer and selective chemical etching on the scribed regions. Organic monolayers are used as a resist material, since it is essential for the resist to be as thin as possible in order to fabricate more precise patterns and surface structures. The results show that high resolution patterns with sub-micrometer scale width can be fabricated on both silicon and various metal surfaces by using this technique.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2003년도 춘계학술대회 논문집
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• pp.50-55
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• 2003

Atomic force microscope(AFM) techniques are increasingly used for tribological studies of engineering surfaces at scales ranging from atomic and molecular to microscale. AFM with suitable tips is being used for nanofabrication nanomachining purposes. In this paper, machining characteristics of silicon have been investigated by nano indentation and nano scratch. Mechanisms of material removal on the microscale are studied and the Taguchi method is introduced to acquire optimum parameters for nanomachining. This work shows effectiveness of the Taguchi method in nanomachining. Also, Acoustic Emission(AE) is introduced for the monitoring of nanomachining.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1992년도 추계학술대회 논문집
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• pp.97-101
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• 1992

Cordierite glass ceramic has become an electronic substrate material for electronic circuits and the use of whiskers for improving strength and toughness is evident. Green sheets of mixtures containing 15% silicon nitride were sintered to greater than 99 % density. The microstructure was analysed using optical microscopy, scanning electron microscopy (SEM), and X-ray diffraction (XRD). The toughness and hardness were improved with increasing the whisker vol. % and sintering temperature. Especially, it is assumed that toughening increasing at the more high sintering temperature relevants to the glass phase increasing, as showned in the roughness of the fracture surfaces. It was directionally dependent of whisker direction during processing.

• 한국전기전자재료학회논문지
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• 제26권5호
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• pp.351-354
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• 2013

Thin-film transistors(TFTs) with silicon-zinc-tin-oxide(SiZnSnO, SZTO) channel layer are fabricated by rf sputtering method. Electrical properties were changed by different annealing treatment of dry annealing and wet annealing. This procedure improves electrical property especially, stability of oxide TFT. Improved electrical properties are ascribed to desorption of the negatively charged oxygen species from the surfaces by annealing treatment. The threshold voltage ($V_{th}$) shifted toward positive as increasing Si contents in SZTO system. Because the Si has a lower standard electrode potential (SEP) than that that of Sn, Zn, resulting in the degeneration of the oxygen vacancy ($V_O$). As a result, the Si acts as carrier suppressor and oxygen binder in the SZTO as well as a $V_{th}$ controller, resulting in the enhancement of stability of TFTs.

• E2M - 전기 전자와 첨단 소재
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• 제7권1호
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• pp.1-6
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• 1994

Cordierite based glass ceramics has become an electronic substrate material for electronic circuits and the use of whickers for improving strength and toughness is evident. Pure cordierite containing 15 vol.% silicon nitride were sintered by hot-prossing and it has above 99% density. Especially, it is assumed that toughening increasing at the more high sintering temperature relevants to the glass phase increasing, as showned in the roughness of the fracture surfaces. It was directionally dependent of whisker drirection during processing.

• 동력기계공학회지
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• 제9권4호
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• pp.118-123
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• 2005

We have investigated the fabrication of Si nanoparticles and $C_{60}$ thin films by pulsed laser ablation. By atomic force microscopy(AFM), the laser-deposited $C_{60}$ thin film was verified to have surface far smoother than the surfaces of films produced by the conventional evaporation method. The Si deposited at a He atmosphere of 0.2 Torr was with about $60{\AA}$ height of the Si nanoparticles, suggesting that it was uniformly deposited. We observed visible green emissions spectra in the $Si/C_{60}$ multilayer films after laser annealing. It is considered that this green emissions is occurred from SiC particles, which is produced reaction of Si nanoparticles with $C_{60}$ by laser annealing.

• International Journal of Precision Engineering and Manufacturing
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• 제9권2호
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• pp.39-43
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• 2008

Atmospheric pressure plasma polishing (APPP) is a noncontact precision machining technology that uses low temperature plasma chemical reactions to perform atom-scale material removal. APPP is a complicated process, which is affected by many factors. Through a preliminary theoretical analysis and simulation, we confirmed that some of the key factors are the radio frequency (RF) power, the working distance, and the gas ratio. We studied the influence of the RF power and gas ratio on the removal rate using atomic emission spectroscopy, and determined the removal profiles in actual operation using a commercial form talysurf. The experimental results agreed closely with the theoretical simulations and confirmed the effect of the working distance. Finally, we determined the element compositions of the machined surfaces under different gas ratios using X-ray photoelectron spectroscopy to study the influence of the gas ratio in more detail. We achieved a surface roughness of Ra 0.6 nm on silicon wafers with a peak removal rate of approximately 32 $mm^{3}$/min.