• Transactions of the Korean Society of Mechanical Engineers B
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• v.27 no.11
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• pp.1572-1578
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• 2003

Particle Image Thermometry(PIT) with liquid crystal tracers is used for visualizing and analysis of the bubbly flow in a vertical temperature gradient. Quantitative data of the temperature were obtained by applying the color-image processing to a visualized image, and neural-network was applied to the color-to-temperature calibration. This paper describes the method, and presents the transient mixing temperature patterns of the bubbly flow.

• 한국정보디스플레이학회:학술대회논문집
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• 2005.07b
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• pp.1067-1070
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• 2005

A large size flat panel LCD-TV must fulfill different requirements than a desktop LCD-monitor: The contrast must be much larger, the viewing angle should be as wide as possible and the switching times must be shorter to allow moving pictures to be displayed naturally. The "Vertically Aligned" technology is most promising to realize such a product. LC-material development for this technology began at Merck about 10 years ago. New materials based on the 1,1,6,7-tetrafluoroindane skeleton were recently synthesized via ortho-metallation and intramolecular Heck cyclization followed by an oxidative fluorination procedure. The materials offer improved properties over liquid crystals currently employed in flat panel LCD-TVs.

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.517-519
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• 2009

We fabricated thin film polarizer by coating lyotropic chromonic liquid crystals (LCLCs) dissolved in anionic monomer solution. Compared to water-based technique, the new method provided many advantages such as excellent coatability, good adhesion to various substrates, and superb surface hardness.

• 한국정보디스플레이학회:학술대회논문집
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• 2007.08a
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• pp.105-108
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• 2007

Chiral liquid crystals exhibit band-gap structures responsive to electrical and optical fields, providing wide-ranging opportunities for photonics applications. We discuss three aspects of this technology: optics of chiral nematic devices and removal of pitch jumps; optical switching of chiral nematic materials; and using novel phases in photonic devices.

• Bulletin of the Korean Chemical Society
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• v.34 no.10
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• pp.2973-2977
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• 2013

In this study, we developed a liquid crystal (LC)-based optical sensor for monitoring enzymatic activity through orientational changes in liquid crystals (LCs) coupled to the properties of a poly-${\small{L}}$-lysine (PLL)-based polymeric membrane. We prepared a PLL-based polymeric membrane at the planar interface between the thermotropic liquid crystal and aqueous phases. The PLL-based polymeric membrane was obtained by contacting the PLL solution with water immiscible LCs, 4-cyano-4'-pentyl-biphenyl (5CB) doped with adipoyl chloride. We then investigated the membrane properties by examining the permeability of the membrane to phospholipids, 1,2-didodecanoyl-rac-glycero-3-phosphocholine (DLPC). The permeability of the membrane to transport phospholipids was monitored through the orientational transition of 5CB in contact with the dispersions of DLPC. Since trypsin can enzymatically catalyze the hydrolysis of PLL, we incubated an aqueous trypsin solution with the membrane for 2 h at room temperature to cause an increase in the permeability of the polymeric membrane to DLPC. As a result, a bright to dark optical shift of LCs was observed, which implied that an enzymatic reaction between trypsin and PLL-based membrane occurred. Two control experiments using chymotrypsin and bovine serum albumin (BSA) revealed no sign of improved permeability based on the orientational transition of LCs.

• 한국신재생에너지학회:학술대회논문집
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• 2006.06a
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• pp.391-394
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• 2006

Growth characteristics of methane-propane clathrate hydrate, growing under different undercooling conditions, was investigated. After the water within pressurized vessel was fully saturated with guest gas molecules by agitation, medium was rapidly undercooled and maintained at the constant temperature. The growth of hydrate was always Initiated with film formations at the upper bounding surface of liquid pool. The visual observation using microscope revealed detailed features of subsequent crystal nucleation, migration, growth and interference occurring within liquid pool. A number of small crystals ascended and settled at the hydrate film. When undercooling was small $({\Delta}T=3.2K)$, some of the settled crystals slowly grew into faceted columns. As the undercooling increased, the downward growth of crystals underneath the hydrate film became dendritic and occurred with greater rate and with finer arm spacing. The shapes of the floating crystals were diverse and included octahedron and triangular or hexagonal platelet When the undercooling was small, the octahedral crystals were found dominant. As the undercooling increased, the shape of the floating crystals also became dendritic. The detailed characteristics of floating crystals were reported in this study.

• Journal of the Korean Ceramic Society
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• v.25 no.6
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• pp.699-703
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• 1988

Domain structures of LiNbO3 crystals grown by Czochralski method were examined according to the growth axis and the rotational speed of crystals. Ring shape and split domain structures were revealed in Z-axis and Y-axis grown crystals respectively. It was found that the domain structures of grown crystals were closely related to the solid-liquid interface shape during growth.

• 한국정보디스플레이학회:학술대회논문집
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• 2004.08a
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• pp.287-288
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• 2004

We report on the development of ferronematic liquid crystals, new materials that consist of a dilute suspension of ferroelectric particles in a nematic liquid crystal host. The particles share their ferroelectric properties with the nematic liquid crystal and impose a spontaneous dielectric polarization of about 10 nC/$cm^2$ to the entire medium, typical for many ferroelectric liquid crystals. As expected, these new materials have enhanced dielectric anisotropy and are sensitive to the sign of an applied electric field. The potential of their use in a number of devices are discussed.

• Korean Journal of Optics and Photonics
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• v.17 no.1
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• pp.23-30
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• 2006

Effects of liquid-crystal droplets size on electro-optical properties of the polymer dispersed liquid crystals are investigated experimentally The liquid crystal droplets size was varied by controlling the Laser power for phase separation and LC/oligomer composition ratio. Electro-optical switching voltage is dependent on the LC/oligomer composition ratio and liquid crystal droplet size. The experimental results showed droplet size will be small and saturation voltage is increased but rise time will be short at high power illumination laser light for phase separation.

• Journal of Information Display
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• v.5 no.2
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• pp.27-38
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• 2004

We describe dried oriented films with anisotropic structural and optical properties prepared from the aqueous solutions of plank-like molecules, the so-called Lyotropic Chromonic Liquid Crystals (LCLCs). The dried LCLC films may be used as optical elements, such as polarizers, compensators, color filters, or retardation plates in the UV, visible, or infrared parts of spectrums. The optical quality of the films is determined by the uniformity of the molecular alignment, which often distorted by periodic variations of the director field. We describe different ways to improve the alignment properties of the films by using additives. We present compositions capable of polarizing effects in visible and UV parts of spectrum.