• Journal of the Microelectronics and Packaging Society
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• v.12 no.4 s.37
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• pp.275-280
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• 2005

We propose a new approach to greatly simplify the fabrication of conventional nanoimprint lithography (NIL) by combined nanoimprint and photolithography (CNP). We introduce a hybrid mask mold (HMM) made from UV transparent material with a UV-blocking Cr metal layer placed on top of the mold protrusions. We used a negative tone photo resist (PR) with higher selectivity to substrate the CNP process instead of the UV curable monomer and thermal plastic polymer that has been commonly used in NIL. Self-assembled monolayer (SAM) on HMM plays a reliable role for pattern transfer when the HMM is separated from the transfer layer. Hydrophilic $SiO_2$ thin film was deposited on all parts of the HMM, which improved the formation of SAM. This $SiO_2$ film made a sub-10nm formation without any pattern damage. In the CNP technique with HMM, the 'residual layer' of the PR was chemically removed by the conventional developing process. Thus, it was possible to simplify the process by eliminating the dry etching process, which was essential in the conventional NIL method.

• Composites Research
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• v.29 no.3
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• pp.111-116
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• 2016

The tilting pad journal bearing for the turbo compressor application has a role to support high speed and heavy loading rotor. White metal has been widely used for the bearing material but the conventional bearing is immediately suspended and induces serious serious damage to the rotor under the unexpected oil cut situation or the insufficient oil film formation. The carbon fiber reinforced composite having high specific stiffness, specific strength and excellent tribological characteristics can solve these seizure problems. In this work, the study on the durability of high thermal resistance carbon fiber/epoxy composite tilting pad journal bearing under oil cut situation was conducted. The material properties of the composite materials including tensile, compressive and interlaminar properties were measured at room and high temperature of oil cut situation. To investigate the possibility of failure of composite tilting pad journal bearing under oil cut situation, the stress distribution of the composite bearing was analyzed via finite element analysis and the Tsai-Wu Failure index was calculated. To verify the failure analysis results, the oil cut tests for the composite tilting pad journal bearing were conducted using industrial test bench.

• Journal of the Korean Electrochemical Society
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• v.5 no.2
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• pp.52-56
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• 2002

Tin oxide was coated on graphite particle by sol-gel method and an electrode with this material having microcrystalline structure for lithium ion battery was obtained by heat treatment in the range $400-600^{\circ}C$. The content of tin oxide was controlled within the range of $2.25wt\%\~11.1wt\%$. The discharge capacity increased with the content of tin oxide and also initial irreversible capacity increased. The discharge capacity of tin oxide electrode showed more than 350 mAh/g at the initial cycle and 300 mAh/g after the 30th cycle in propylene carbonate(PC) based electrolyte whereas graphite electrode without surface modification showed 140 mAh/g. When the charge and discharge rate was changed from C/5 to C/2, The discharge capacity of tin oxide and graphite electrode showed $92\%\;and\;77\%$ of initial capacity, respectively. It has been considered that such an enhancement of electrode characteristics was caused because lithium $oxide(Li_2O)$ passive film formed from the reaction between tin oxide and lithium ion prevented the exfoliation of graphite electrode and also reduced tin enhanced the electrical conduction between graphite particles to improve the current distribution of electrode.

• Journal of the Korean Electrochemical Society
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• v.12 no.2
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• pp.173-180
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• 2009

In order to develop a novel polymer electrolyte membrane for direct methanol fuel cell (DMFC), styrene monomer was graft-polymerized into poly(tetrafluoroethylene perfluoropropyl vinyl ether) (PFA) film followed by a sulfonation reaction. The graft polymerization was prepared by the $\Upsilon$-ray radiation-grafting method. Subsequently, sulfonation of the radiation-grafted film was carried out in a chlorosulfonic acid/1,2-dichloroethane (2 v/v%) solution. The chemical, physical, electrochemical and morphological properties of the radiation-grafted membranes (PFA-g-PSSA) were characterized by fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The water uptake, ionic conductivity, and methanol permeability of the PFA-g-PSSA membrane were also measured. The cell performances of MEA prepared with the PFA-g-PSSA membranes were evaluated and the cell resistances were measured by an impedance analyzer. The MEA using PFA-g-PSSA membranes showed superior performance for DMFCs in comparison with the commercial Nafion 112 membrane.

• Cartoon and Animation Studies
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• s.49
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• pp.697-712
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• 2017

In recent years, film and animation for cinematic release have embraced stereoscopic vision and the three-dimensional depth it creates for the viewer. The maturation of consumer-level virtual reality (VR) technology simultaneously spurred a wave of media productions set within 3D space, ranging from computer games to pornographic videos, to Academy Award-nominated animated VR short film Pearl. All of these works rely on stereoscopic fusion through stereopsis, that is, the perception of depth produced by the brain from left and right images with the amount of binocular parallax that corresponds to our eyes. They aim to emulate normal human vision. Within more experimental practices however, a fully rendered 3D space might not always be desirable. In my own abstract animation work, I tend to favour 2D flatness and the relative obfuscation of spatial relations it affords, as this underlines the visual abstraction I am pursuing. Not being able to immediately understand what is in front and what is behind can strengthen the desired effects. In 2015, Jeffrey Shaw challenged me to create a stereoscopic work for Animamix Biennale 2015-16, which he co-curated. This prompted me to question how stereoscopy, rather than hyper-defining space within three dimensions, might itself be used to achieve a confusion of spatial perception. And in turn, how abstract and experimental moving image practices can benefit from stereoscopy to open up new visual and narrative opportunities, if used in ways that break with, or go beyond stereoscopic fusion. Noteworthy works which exemplify a range of non-traditional, expanded approaches to binocular vision will be discussed below, followed by a brief introduction of the stereoscopic animation loop III=III which I created for Animamix Biennale. The techniques employed in these works might serve as a toolkit for artists interested in exploring a more experimental, expanded engagement with stereoscopy.

• Journal of Sensor Science and Technology
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• v.1 no.2
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• pp.173-181
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• 1992

Tantalum pentoxide($Ta_{2}O_{5}$) thin films on p-type (100) silicon wafer were fabricated by RF reactive sputtering. Physical properties and structure of the specimens were examined by XRD and AES. From the C-V analysis, the dielectric constant of $Ta_{2}O_{5}$ films was in the range of 10-12 in the reactive gas atmosphere in which 10% of oxygen gas is mixed. The ratio of Ta : 0 was 1 : 2 and 1 : 2.49 by AES and RBS examination, respectively. The heat-treatment at $700^{\circ}C$ in $O_{2}$ ambient led to induce crystallization. When the heat-treatment temperature was $1000^{\circ}C$, the dielectric constant was 20.5 in $O_{2}$ ambient and 23 in $N_{2}$ ambient, respectively. The crystal structure of $Ta_{2}O_{5}$ film was pseudo hexagonal of ${\delta}-Ta_{2}O_{5}$. The flat band voltage shift(${\Delta}V_{FB}$) of the specimens and the leakage current density were decreased for higher oxygen mixing ratio. The maximum breakdown field was 2.4MV/cm at the oxygen mixing ratio of 10%. The $Ta_{2}O_{5}$ films will be applicable to hydrogen ion sensitive film and gate oxide material for memory device.

• Journal of Sensor Science and Technology
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• v.7 no.3
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• pp.147-153
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• 1998

The strain characteristics of a fiber optic Fabry-Perot pressure sensor with high sensitivity using a $Si_{3}N_{4}/SiO_{2}/Si_{3}N_{4}$ (N/O/N) diaphragm is experimentally investigated. A 600 nm thick N/O/N diaphragm was fabricated by silicon anisotropic etching technology in 44 wt% KOH solution. An interferometric fiber optic pressure sensor has been manufactured by using a fiber optic Fabry-Perot intereferometer and a N/O/N diaphragm. The 2 cm length fiber optic Fabry-Perot interferometers in the continuous length of single mode fiber were produced with two pieces of single mode fiber coated with $TiO_{2}$ dielectric film utilizing the fusion splicing technique. The one end of the fiber optic Fabry-Perot interferometer was bonded to a N/O/N diaphragm. and the other end was connected to an optical setup through a 3 dB coupler. For the N/O/N diaphragm sized $2{\times}2\;mm^{2}$ and $8{\times}8\;mm^{2}$, the pressure sensitivity was measured 0.11 rad/kPa and 1.57 rad/kPa, respectively, and both of the nonlinearities were less than 0.2% FS.

• Journal of Surface Science and Engineering
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• v.50 no.1
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• pp.35-41
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• 2017

$TiO_2$, $Al_2O_3$, and $TiO_2-Al_2O_3$ nanolaminated films were grown by atomic layer deposition (ALD) on the 316L stainless steel (SS316L) substrates at a temperature of $150^{\circ}C$. The growth kinetics of $ALD-TiO_2$ and $Al_2O_3$ thin films were systematically investigated in order to precisely control the thickness of each layers in the $TiO_2-Al_2O_3$ nanolaminated films using a high-resolution transmission electron microscopy. And, the exact deposition rates of $ALD-TiO_2$ on $Al_2O_3$ surface and $ALD-Al_2O_3$ on $TiO_2$ surface were revealed to be 0.0284 nm/cycle and 0.11 nm/cycle, respectively. At given growth conditions, the microstructures of $TiO_2$, $Al_2O_3$ and $TiO_2-Al_2O_3$ nanolaminated films were amorphous. The potentiodynamic polarization test revealed that the $TiO_2-Al_2O_3$ nanolaminated film coated SS316L had a best corrosion resistance, although all ALDcoated SS316L exhibited a clear improvement of the corrosion resistance compared with a bare SS316L.

• Journal of the Korean Ceramic Society
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• v.39 no.7
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• pp.649-656
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• 2002

In situ patterned zinc oxide thin films were prepared by precipitation of Zn(NO$_3$)$_2$ aqueous solution containing urea and by microcontact printing using Self-Assembled Monolayers(SAMs) on A1/SiO$_2$/Si substrates. The visible precipitation of Zn(OH)$_2$ that was formed in the Zn(NO$_3$)$_2$ aqueous solution containing urea was enhanced with an increase of the reaction temperature and the amount of urea. As the reaction time of Zn(NO$_3$)$_2$ with urea was prolonged, the thickness and grain size of Zn(OH)$_2$ thin layers were increased, respectively. The optimum precipitation condition was at 80$\^{C}$ for 1 h for the solution with the ratio of Zn(NO$_3$)$_2$ to urea of 1 : 8. Homogeneous ZnO thin films were fabricated by the heat treatment of 600$\^{C}$ for 1 h of Zn(OH)$_2$ precipitation on Al/SiO$_2$/Si substrate. This was available to the in-situ patterned ZnO thin films with uniform grain size. Hydrophobic SAM, Octadecylphosphonic Acid(OPA) and hydrophilic SAM, 2-Carboxyethylphosphonic Acid(CPA) were applied on the Al/SiO$_2$/Si substrate by microcontact printing method. In situ patterned ZnO thin film was successfully prepared by the heat treatment of Zn(OH)$_2$ precipitated on the surface of hydrophilic SAM, CPA.

• Polymer(Korea)
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• v.30 no.2
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• pp.140-145
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• 2006

The mort commonly available substrate material is glass in the display fibrication process. However, glass is not desirable due to its heaviness and fragility. Recently, plastics such polysulfone (PSF), polyethesulfone (PES), polycarbonate (PC), polyethylene terephthalate (PET) and cyclic olefin polymers (COP) have been investigated to replace glass as a substrate material for display fibrication. Plastic substrates are advantageous in that they are lightweight, huh impart resistance, flexibility, and ability for roll to roll manufacturing process. But many plastics have poor chemical resistance in organic solvent. The chemica resistance is also lequired because they are exposed to solvents for various chemical treatments din the manufacturing process. So, we have an interest in the chemical modification of PSF to improve chemical resistance. We introduced crosslinkable imide moieties using chloromethylation method for the modification of PSF which could be overcome above shortcomings for display substrate based on plastic film. We prepared the cross-linked polysulfone films which were represented chemical resistance in HeOH, THF, DMSO and NMP. The thermal properties were measured by TGA, DSC and TMA. As the results, we have confirmed to enhance of the thermal property. They had low coefficient of thermal expansion (CTE) which decreased to 15% and had increased $T_g\;from\;180^{\circ}C\;to\;252^{\circ}C$. Cross-linked polysulfone films with imide side-chain had good optical properties and chemical resistance so that they could be used as flexible display substrate.