• Proceedings of the KIEE Conference
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• 1996.07c
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• pp.1950-1953
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• 1996

A $1\;{\times}\;4$ micro mirror array is designed and fabricated. In contrast to other micro mirrors which utilize torsional flexure hinges or cantilevers for restoring torque and supporting purpose, we have placed a substrate hinge structure under each mirror. Each micro mirror consists of address electrode, substrate hinge consisting of pin and staple, supporter post, and mirror plate. Electrical connection between mirror plate and ground electrode is established by substrate hinge. Mirror undergoes a rotational motion due to electrostatic force when voltage difference is applied between address electrode and mirror plate. Micro mirrors with two different types of staple shape and two different pin sizes are designed and fabricated. Each mirror is designed to have ${\pm}\;10^{\circ}$ of deflection angle and have $100\;{\times}\;110\;{\mu}m^2$ of size.

• Journal of the Korean Ceramic Society
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• v.20 no.3
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• pp.199-204
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• 1983

An attempt was made to study wetting behavior of various low temperature molten frist on ceramic substrates including high alumina silicon carbide and porous fired clay plates by Sessile-drop method. The cosine values of contact angles between substrates and molten frist were linear as a function of temperature unless chemical reactions between substrate and molten frit occured. Addition of BaO to frit composition indicated that cosine of values of contact angles were gradually increased with increasing temperature but in the frist contained $Li_2O$ consine values were abruptly increased with increasing temperature after reached a certain temperature. The contact angle increased with increasing roughness of the substrate surface in case of alumina substrate plate.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.53 no.1
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• pp.47-52
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• 2004

3D microstructures with different side-wall angles and different scales are fabricated by both methods of inclined exposure and rear-side exposure at each of selected areas on a same substrate. Conventional methods of inclined exposure are used to make side-walls with a same inclined angle on one substrate and to get a scale error due to front-side exposure through thick photoresist layer, But, by using the proposed method, we are able to fabricate 3D microstructures on a same substrate with various side-wall angles and accurate dimensions as the original design. In the rear-side exposure, UV exposure light reflects from the chromium mask pattern after passing through the thick photoresist layer, resulting in fabrication of well-defined, inclined 3D structures inside the thick photoresist layer.

• Steel and Composite Structures
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• v.44 no.1
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• pp.17-31
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• 2022

This investigation studies the characteristics of wave dispersion in sigmoid functionally graded (SFG) curved beams lying on an elastic substrate for the first time. Homogenization process was performed with the help of sigmoid function and two power laws. Moreover, various materials such as Zirconia, Alumina, Monel and Nickel steel were explored as curved beams materials. In addition, curved beams were rested on an elastic substrate which was modelled based on Winkler-Pasternak foundation. The SFG curved beams' governing equations were derived according to Euler-Bernoulli curved beam theory which is known as classic beam theory and Hamilton's principle. The resulted governing equations were solved via an analytical method. In order to validate the utilized method, the obtained outcomes were compared with other researches. Finally, the influences of various parameters, including wave number, opening angle, gradient index, Winkler coefficient and Pasternak coefficient were evaluated and indicated in the form of diagrams.

• Journal of Computational Design and Engineering
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• v.3 no.3
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• pp.198-214
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• 2016

Oval substrates are widely used in automobiles to reduce the exhaust emissions in Diesel oxidation Catalyst of CI engine. Because of constraints in space and packaging Oval substrate is preferred rather than round substrate. Obtaining the flow uniformity is very challenging in oval substrate comparing with round substrate. In this present work attempts are made to optimize the inlet cone design to achieve the optimal flow uniformity with the help of CATIA V5 which is 3D design tool and CFX which is 3D CFD tool. Initially length of inlet cone and mass flow rate of exhaust stream are analysed to understand the effects of flow uniformity and pressure drop. Then short straight cones and angled cones are designed. Angled cones have been designed by two methodologies. First methodology is rotating flow inlet plane along the substrate in shorter or longer axis. Second method is shifting the flow inlet plane along the longer axis. Large improvement in flow uniformity is observed when the flow inlet plane is shifted along the direction of longer axis by 10, 20 and 30 mm away from geometrical centre. When the inlet plane is rotated again based on 30 mm shifted geometry, significant improvement at rotation angle of $20^{\circ}$ is observed. The flow uniformity is optimum when second shift is performed based on second rotation. This present work shows that for an oval substrate flow, uniformity index can be optimized when inlet cone is angled by rotation of flow inlet plane along axis of substrate.

• Journal of the Korean Ceramic Society
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• v.42 no.7 s.278
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• pp.497-502
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• 2005

This study investigated the effects of the substrate and powder content on the fabrication of SiO$_{2}$ photonic crystals by evaporation method. Photonic crystals were self-assembled on quartz, Corning 1737 glass, slide glass, and ITa glass to verify the effects of the wetting angle and surface morphology. The powder contents of the solution were varied from 0.2 to 2.0 wt$\%$. The number of photonic crystal layers increased according to the decrease of wetting angle and surface roughness. The resultant photonic crystals showed the best optical characteristics when the number of photonic crystal layers was within 40 and 50. In addition, the intensity peak of Fabry¡?Perot fringes increased when the wetting angle was large and the particle size was small. Photonic crystals coated on ITO glass showed the highest reflectance peak of 63$\%$ relative intensity.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.07a
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• pp.199-202
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• 2003

We have investigated the generation of pretilt angle for a nematic liquid crystal (NLC) alignment with rubbing alignment method on two kinds of polyimide (PI) surfaces using thin plastic substrates. The generated NLC pretilt angles on the pre-imidized type PI are about $3.8^{\circ}$ by the rubbing alignment method with thin plastic substrates, However, the pretilt angle measured at about $2.8^{\circ}$ lower on the polyamic acid type PI than by pre-imidized type PI surface with thin polymer film. The tilt angle increases as increasing curring temperature for making polyimide layer using polyamic acid type PI. It was concluded that pretilt angle in the polyimide surface is attributable to the increasing of imide rato.

• Transactions of the Society of Information Storage Systems
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• v.7 no.1
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• pp.19-24
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• 2011

Holographic Data Storage System, one of the next generation data storage devices, is a 2-dimensional page oriented memory system using volume holograms in writing and retrieving process. Recently photopolymer with disc type substrate was selected as a media for the Holographic Data Storage System. The disc tilt occurs when the media rotates and the external disturbance applies. The disc tilt causes the change of the angle between the reference beam and the media, the data cannot be retrieved with the right angle or other data page is retrieved. The tilt is generated in a 2-axis direction (tangential, radial). The tangential tilt direction is the same with the multiplexing plane, while the radial tilt direction is a perpendicular to the multiplexing plane. In this research we propose 2-axis tilt angle servo system. The tilt errors are measured by using external photo detector and the additional red laser. Then the tangential direction tilt is compensated by using the galvano mirror. Also the radial direction tilt is compensated by the rotating prism between the relay lens in the reference field. Finally we confirm the compensation results through the Signal to Noise Ratio(SNR) and Bit Error Rate(BER).

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.65 no.1
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• pp.53-56
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• 2016

Because of the low pollution resistance of the porcelain electrical insulator itself, in this work the anti-pollution performance of insulator was improved by using the functional coating. The ceramic substrates that components were same as the porcelain electrical insulator were used in this experiment. The functional films were coated on the ceramic substrate by using a spray coating method, and then the coated substrate were annealed under different coating condition such as natural curing and annealing temperature of $200^{\circ}C$, $300^{\circ}C$ and $400^{\circ}C$. Then, the contact angles of the coated surfaces were measured and the minimum angle ($8.3^{\circ}$) was obtained at $400^{\circ}C$. The anti-contamination properties were measured, revealing that as the contact angle decreased, the anti-contamination properties improved. The hardness and adhesion were small at the natural curing condition however the excellent mechanical properties were obtained under higher temperature annealing.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.126-126
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• 2012

Copper is considered to be the most promising substrate, especially Cu(111), for the growth of high quality monolayer graphene. Since interactions between graphene and Cu substrates will influence on the orientation, quality, and electrical properties of synthesized graphene, we experimentally determine a weak interfacial interaction between Cu(111) substrate and graphene using angle-resolved photoemission spectroscopy (ARPES). The measurement was conducted from the initial stage to the formation of a graphene monolayer. Graphene growth was initiated along the Cu(111) lattice, and two rotated graphene domains were grown, where no significant differences were observed in the band structure depending on different orientations. The interaction, including electron transfer from the Cu(111) to graphene, was limited between the Shockley state of the Cu(111) surface and the ${\pi}$ bands of graphene. These results provide direct information on the growth behavior and interactions between the Cu(111) and graphene.