• Journal of Satellite, Information and Communications
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• v.10 no.1
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• pp.67-70
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• 2015

We studied the state of the dual liquid crystal (LC) alignment which displays both homeotropic and homogeneous alignment on blended polyimide (PI) layer. The research was conducted using rubbing method at different imidizing temperatures and the blended PI was made using homeotropic PI having an alkyl side chain and homogeneous PI without the side chain. The uniform LC alignments were achieved, and have thermal stability. The results of contact angles were similar to that of pretilt angles.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.11a
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• pp.311-312
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• 2006

We studied homeotropic alignment effect for a nematic liquid crystal (NLC) on the $SiO_x$, thin film irradiated by the new ion beam method $SiO_x$ thin films were deposited by plasma enhanced chemical vapor deposition (PECVD) and were treated by the DuoPIGatron ion source. A uniform liquid crystal alignment effect was achieved over 2100 eV ion beam energy. Tilt angle were about $90^{\circ}$ and were not affected by various ion beam energy.

• Transactions on Electrical and Electronic Materials
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• v.17 no.2
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• pp.109-112
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• 2016

We demonstrated an alternative electrically controlled birefringence liquid crystal (ECB-LC) system with ion beam (IB)-irradiated yttrium gallium oxide (YGaO) alignment films using a sol-gel process. The surface roughness of the films was dependent on the annealing temperature; aggregated particles on surface were observed at lower annealing temperatures, whereas a smooth surface could be obtained with higher annealing temperatures. Higher transmittance in the visible region was observed at higher annealing temperatures. The film had an amorphous crystallographic state irrespective of the annealing temperature. Furthermore, ECB-LC cell with our IB-irradiated YGaO film yielded faster response time when compared to ECB-LC cell with rubbed polyimide. Considering the fast response time and high transmittance, the IB-irradiated YGaO-base LC system is a powerful alternative application for the liquid crystal display industry.

• 한국정보디스플레이학회:학술대회논문집
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• 2003.07a
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• pp.595-599
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• 2003

We have studied the phase transition to look for molecular structure by using several different techniques for new banana-shaped liquid crystals shown in Fig. 1. Based on the similarities to recently observed fluro-contaning materials (switching involves layer structure rearrangement, increasing threshold with increasing temperature) for HC sample (where x is H), we assume that the phase C has a triclinic symmetry corresponding to the double tilted $smC_G$ Phase. The observation that the polarization peak appears at lower field ($E_o{\sim}15V/{\mu}m$) than the amplitude of the threshold ($E_{th}$) can be explained assuming a field induced $SmC_G$ - SmCP (or SmAP) transition at $E_{th}$

• 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.

• Bulletin of the Korean Chemical Society
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• v.23 no.4
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• pp.587-592
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• 2002

Photocrosslinkable chalcone-epoxy compound comprising 1,3-bis-(4-hydroxy-phenyl)-propenone was synthe-sized for fabricating the photo-alignment layer of liquid crystals. Chalcone group was introduced into the main chain unit of the epoxy oligomer. We observed a photodimerization behavior and an optical anisotropy of this material by irradiation of a linearly polarized UV(LP-UV) light. With a trace amount of cationic photoinitiator (TRS-HFA), polymerization of epoxy groups was also conducted at the similar wavelength range used for photodimerization. Linearly polarized UV irradiation on the chalcone-epoxy films with cationic photoinitiator induced optical anisotropy of the film and the resultant film can be used for alignment layers for low molecular weight nematic liquid crystals.

• Journal of Energy Engineering
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• v.13 no.4
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• pp.301-310
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• 2004

Carbon dioxide ocean disposal is one of the promising options to reduce carbon dioxide concentration in the atmosphere. So, in the present study, calculations of the solubility, the surface concentration and the dissolution behavior of carbon dioxide when liquid carbon dioxide is released at 1,000m and 1,500m in depth are performed. The results show that liquid carbon dioxide changes to carbon dioxide bubbles around 500m in depth, and the hydrate acts as a resistant layer for the dissolution of liquid carbon dioxide. Also. the injection of liquid carbon dioxide from a moving ship is more effective than that from a fixed pipeline.

• Transactions on Electrical and Electronic Materials
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• v.14 no.2
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• pp.82-85
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• 2013

This paper introduces 6,13-bis(triisopropylsilylethynyl) pentacene (TIPS pentacene) doped liquid crystal (LC) alignment properties on a rubbed polyimide (PI) layer as a function of the doping concentration of TIPS pentacene. Pretilt angles, photomicrographs, and electro-optical properties of TIPS pentacene doped LCs were comparable to those of pure LCs. However, TIPS pentacene in a LC medium supported twisted nematic-liquid crystal displays (TN-LCDs) to improve electro-optical properties. The threshold voltages observed in the TN cells decreased as the TIPS pentacene concentration increased. In addition, suitable response times were observed in TN cells.

• Biomolecules & Therapeutics
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• v.10 no.4
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• pp.281-286
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• 2002

In this study, we intended to get a preliminary data for establishing rat tracheal surface epithelial(RTSE) cell culture system as an experimental model for physiology and pharmacology of tracheal epithelial cells. Primary culture on the membrane support and application of the air-liquid interface system at the level of cell layer were performed. The cell growth rate and mucin production rate were measured according to the days in culture. The results were as follows: this culture system was found to manifest mucocilliary differentiation of rat tracheal epithelial cells, the cells were confluent and the quantity of produced and released mucin was highest on culture day 9, the mucin was mainly released to the apical side and tbe free $^3{H}$-glucosamine which was not incorporated to process of synthesis of mucin was left on the basolateral side. Taken together, we suggest that air-liquid interface culture system can be used as a substitute for immersion culture system and as an experimental model for in vivo mucus-hypersecretory diseases.

• Smart Structures and Systems
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• v.28 no.6
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• pp.839-853
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• 2021

In this paper, a novel multimode liquid metal-based pressure sensor is developed. The main body of the sensor is composed of polydimethylsiloxane (PDMS) elastomer. The structure of the sensor looks like a sandwich, in which the upper structure contains a cylindrical cavity, and the bottom structure contains a spiral microchannel, and the middle partition layer separates the upper and the bottom structures. Then, the liquid metal is injected into the top cavity and the bottom microchannel. Based on linear elastic fracture mechanics, the deformation of the microchannel cross-section is theoretically analyzed. The changes of resistance, capacitance, and inductance of the microchannel under pressure are deduced, and the corresponding theoretical models are established. The theoretical values of the pressure sensor are in good agreement with experimental data, implying that the developed theoretical model can explain the performance of the sensor well.