• Journal of Welding and Joining
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• v.19 no.4
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• pp.423-428
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• 2001

The bonding phenomena of Ni base single crystal superalloy. CMSX-4 during transient liquid phase(TLP) bonding was investigated using MBF-80 insert metal. Bonding of CMSX-4 was carried out at 1,373∼1,548K for 0∼19.6ks in vacuum. The (001) orientation of each test specimen was aligned perpendicular to the bonding interface. The dissolution width of base metal was increased when the bonding temperature and holding time were increased. The eutectic width diminished linearly with the square root of holding time during isothermal solidification process. Borides were formed in the bonded layer during TLP bonding operation. The solid phase grew epitaxially into the liquid phase from substrates and single crystallization could be readily achieved during the isothermal solidification.

• Proceedings of the Korea Association of Crystal Growth Conference
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• 1997.06a
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• pp.253-259
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• 1997

The iron doped GaAs single crystals were grown by liquid phase epitaxial method and its some physical properties were evaluated with a view to investigate the crystal quality and emission property. The isomer shift of 0.303mm/sec is calculated from low-temperature M ssbauer spectroscopy and we know that charge state of iron ion is 3+ in GaAs crystal. In low temperature photoluminescence, the deep emission bands with wide-line width have been observed at 0.99eV and 1.15eV in addition to sharp excitonic peaks. We attributed that these deep emissions are originated from substitutional Fe-acceptor which has charge state of 3+ and 2+, respectively.

• Journal of Information Display
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• v.6 no.2
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• pp.1-6
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• 2005

We demonstrated stability-enhanced liquid crystal (LC) displays using pixel-isolated LC mode in which LC molecules are isolated in pixel by horizontal polymer layer and vertical polymer wall. The device shows good electro-optic properties against external point or bending pressure due to the polymer structures. The polymer wall acts as supporting structure from mechanical pressure and prevents the cell gap from bending. Moreover, the polymer layer acts as an adhesive to ensure a tight attachment of the two substrates. We present herein various methods for producing polymer structures by using an anisotropic phase separation from LC and polymer composites or patterned micro-structures for stable flexible liquid crystal displays.

• Journal of the Korean Graphic Arts Communication Society
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• v.13 no.2
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• pp.19-32
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• 1995

Liquid crystal-polymer composite(LCPC) films are promising new materials for both projection displays and vision products. LCPC films consist of a continuous liquid crystal phase embedded in a three- dimensional network of polymer matrix. The liquid crystal in these LC phases can be electrically switched giving rise to an opaque scattering off-state and a transparent, non- scattering on-state. In this work, a premixture is composed of LC, UV-curable monomer and photonitiator. LCPC films are formed by photopolymerization induced phase separation from this premixture. In conclusion, structure and electro-optical properties of LCPC films strongly depends on the selection of monomer, LC content and curing rate.

• Journal of the Korean Society for Precision Engineering
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• v.22 no.8 s.173
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• pp.84-91
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• 2005

The role of microstructure is quite significant in fretting of Ti-6Al-4V since its material properties depend strongly on crystallographic texture. In this study, we adopt crystal plasticity theory with a 2-D planar triple slip idealization to account fur microstructure effects such as grain orientation distribution, grain geometry, as well as $\alpha$ colony size. Crystal plasticity simulations suggest strong implications of microstructure effects at fretting contacts.

• Journal of Welding and Joining
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• v.19 no.3
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• pp.325-333
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• 2001

The effect of base metal grain size on isothermal solidification behavior of Ni-base superalloy, CMSX-2 during transient liquid phase (TLP) bonding was investigated employing MBF-80 insert metal. TLP-bonding of single crystal. coarse-grained and fine-grained CMSX-2 was carried out at 1373∼1548k for various holding time in vacuum. The eutectic width diminished linearly with the square root of holding time during isothermal solidification process for single crystal, coarse-grained and fine-grained base metals. The completion time for isothermal solidification decreased in the order ; single crystal, coarse-grained and fine-grained base metals. The difference of isothermal solidification rates produced when bonding the different base metals could be explained quantitatively by the effect of base metal grain boundaries on the apparent average diffusion coefficient of boron in CMSX-2.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.637-637
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• 2013

We develop single-crystal poly(3,4-ethylenedioxythiopene nanowires using liquid-bridge-mediated nanotransfer printing via vapor phase polymerization. This direct printing method can simultaneously enable the synthesis, alignment and patterning of the nanowires from molecular ink solutions. Twoor three-dimensional complex structures of various single-crystal organic nanowires were directly fabricated over a large area using many types of molecular inks. This method is capable of generating several optoelectronic devices. LB-nTM is based on the direct transfer of various materials from a mold to a substrate via a liquid bridge between them. To demonstrate its usefulness, we used LB-nTM to fabricate nanowire field-effect transistors and arrays of 6,13-bis (triisopropyl- silylethynyl) pentacene (TIPS-PEN) nanowire field-effect transistors.

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.1447-1449
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• 2009

We report the syntheses bis-(N,N-diethylaminoethyl) perylene-3,4,9,10-tetracarboxylic diimide (PDI) of lyotropic chromonic liquid crystal and it dissolves in photocurable ionic monomer solution. PDI-acrylic acid solution was observed whether liquid crystal phase appeared in each concentration. Thin film polarizer was prepared by simultaneously coating and aligning the solution of PDI-acrylic acid (in the chromonic nematic phase) onto glass substrates using a mechanical shearing force and was cured by irradiation of UV light. Also Photopatterned polarizer is manufactured by same process.

• Journal of the Korean Society of Propulsion Engineers
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• v.23 no.3
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• pp.44-50
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• 2019

HNIW is a high energy material and has four crystalline phases, it is known that the thermal properties of the material depend on the crystal phase. In this sturdy, the viscosity, mechanical and burning properties of a solid propellant with nitrate ester polyester(NEPE) system with respect to the crystal phases of HNIW. According to the crystal phase of HNIW, the mechanical properties of the cured propellant did not change considerably, however differences were observed in the burning properties. Considering both a high density and stable burning properties, the optimum crystal phase of HNIW can be identified as the main factor influencing to the NEPE system propellant.

• 한국정보디스플레이학회:학술대회논문집
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• 2002.08a
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• pp.939-942
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• 2002

The optically addressed and electrically addressed spatial phase only light modulators without pixelized structures have been developed. A sufficient phase modulation capability and a high diffraction efficiency of these devices are useful for practical applications.