• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.11a
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• pp.117-120
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• 2001

A new photoalignment material PFCPMI, poly [4-(fluorocinnamate) phenylmaleimide], was synthesized and the nematic liquid crystal (NLC) aligning capabilities on the photopolymer surface. The NLC pretilt angle generated by non-UV filter method on the PFCPMI surface was higher than that of the UV filter method. A good LC alignment by non-UV filter method was observed at 150\`c of annealing temperature. However, the alignment defect of the NLC by UV filter method was measured above 150$^{\circ}C$ of annealing temperature. Consequently, the high pretilt angle and the good LC alignment in NLC using non-UV filter method can be achieved.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.15 no.5
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• pp.423-428
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• 2002

The photoalignment material PFCPMI, poly[4-(fluorocinnamate)phenylmaleimide], was synthesized and the nematic liquid crystal(NLC) aligning capabilities on the photopolymer surface. The NLC pretilt angle geneated by non-UV filter method on the PFCPMI surface was higher than that of the UV filter method. A good LC alignment by non-UV filter method was observed at $150^{\circ}C$ of annealing temperature. However, the alignment defect of the NLC by UV filter method was measured above $150^{\circ}C$ of annealing temperatue. Consequently, the high pretilt angle and the good LC alignment in NLC using non-UV filter method can be acheived.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.15 no.5
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• pp.419-422
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• 2002

We studied the nematic liquid crystal (NLC) aligning capabilities using the new alignment material of a diamond like carbon (DLC) thin film. A high pretilt angle of about $3.5^{\circ}$ by ion beam(IB) exposure on the DLC thin film surface was measured. A good LC alignment by the IB alignment method on the DLC thin film surface was observed at annealing temperature of $200^{\circ}C$, and the alignment defect of the NLC was observed above annealing temperature of $220^{\circ}C$. Consequently, the high NLC pretilt angle and the good thermal stability of LC alignment by the IB alignment method on the DLC thin film surface can be achieved.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.21 no.5
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• pp.474-480
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• 2008

In order to make full color cholesteric displays, color filter-less R, G, B sub-pixel structured cholesteric LC cells have been studied. To make R, G, B colors, UV induced pitch variant chiral dopant was added to cholesteric LC mixtures. The concentration of the photo-sensitive chiral dopant was adjusted so that the initial state showed blue color and the color was changed from blue to green and red with increase of UV irradiation to the cholesteric cells. To prevent the mixing of R, G, B reflective sub-pixel liquid crystals, separation walls were formed using negative photo resister in boundary area between sub-pixels, Through the optimization of the material concentrations and UV irradiation condition, vivid R, G, B colors were achieved.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.11a
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• pp.502-505
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• 2003

We synthesized high thermal photoalignment material with hydroxyl aromatic polyimide, and studied the liquid crystal (LC) aligning capabilities on the photopolymer layers. Also, electro-optical (EO) performances for the twisted-nematic (TN)-liquid crystal display (LCD) photoaligned with linearly polarized UV exposure were investigated. A good LC alignment with UV exposure on the photopolymer surface can be obtained. However, the low pretilt angles were obtained below $1^{\circ}$. The Voltage-transmittance (V-T) curve without backflow bounce in the photoaligned TN cell with UV exposure was observed. The response time of photoaligned TN cell was measured about 24 ms.

• Transactions on Electrical and Electronic Materials
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• v.7 no.1
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• pp.21-25
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• 2006

In this study, liquid crystal (LC) aligning properties for homeotropic alignment on the $SiO_x$ thin film by electron beam evaporation method with electron beam system in accordance with the evaporation angles were investigated. Also, the control of pretilt angles homeotropic aligned LC on $SiO_x$ thin film as the function of the evaporation angles were studied. The uniform vertical LC alignment on the $SiO_x$ thin film surfaces with electron beam evaporation was achieved with all of the thin film angle conditions. It is considerated that the LC alignment on the $SiO_x$ thin film by electron beam evaporation is attributed to elastic interaction between LC molecules and micro-grooves at the $SiO_x$ thin film surface created by evaporation. The values of the pretilt angles according to the evaporation angle were from about $0.7^{\circ}$ to about $3.4^{\circ}$. The highest pretilt angles of about $3.4^{\circ}$ in aligned NLC on the $SiO_x$ thin film surfaces by electron beam evaporation were measured under the condition of $45^{\circ}$. Also, good LC alignment states on the treated $SiO_x$ thin film layer by electron beam evaporation were observed at annealing temperature of $250^{\circ}C$. Consequently, the high pretilt angle and the good thermal stability of LC alignment on the $SiO_x$ thin film by electron beam evaporation can be achieved.

• Journal of Microbiology and Biotechnology
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• v.26 no.3
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• pp.493-497
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• 2016

Glucosyl rubusosides were synthesized by two dextransucrases. LcDexT was obtained from Leuconosotoc citreum, that LlDexT was obtained from Leuconostoc lactis. LcDexT and LlDexT regioselectively transferred a glucosyl residue to the 13-O-glucosyl moiety of rubusoside with high yield of 59-66% as analyzed by TLC and HPLC. Evaluation of the sweetness of these glucosyl rubusosides showed that their quality of taste, in particular, was superior to that of rubusoside. These results indicate that transglucosylation at the 13-O-glucosyl moiety of rubusoside by different regioselective dextransucrases can be applicable for increasing its sweetness and quality of taste.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.07b
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• pp.1050-1053
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• 2003

Polymer dispersed liquid crystal mode can be classified into two cases, normally scattering mode (NS) and normally transparent (NT) mode according to an initial state. Electro-optic characteristic NS/NT PDLC mode can be improved by controlling the factors to influence the phase separation. In case of NS PDLC mode, we inspected change of a phase separation as a function of curing temperature for the mixture of E7 and NOA65 with different ratios. When the LC concentration is less than polymer such as LC : NOA65 = 40 : 60wt%, the PDLC cell is influenced strongly by the curing temperature. However, when LC concentration is much less than polymer such as LC : NOA65 : 80 : 20wt%, it is influenced slightly by the curing temperature. In case of NT PDLC mode, we observed change of a phase separation as a function of the ratio of the mixture and UV conditions such as curing temperature, UV intensity The cell made with strong UV intensity and curing temperature of $20^{\circ}C$, in case that the ratio of LC to polymer is 70:30wt%, showed good electro-optic characteristics.

• Journal of the korean academy of Pediatric Dentistry
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• v.23 no.2
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• pp.450-460
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• 1996

The purpose of this study was to compare shear bond strength of composite resin using several dentin bonding agents and light cured glass ionomer cement(Fuji II LC). 40 Bovine primary anterior teeth were used for this experiment. Labial surface of teeth were flattened. It were divided into four groups. Each group was composed of 10 teeth. The material used for this experiment were Scotchbond Multipurpose-Z-100, Allbond 2-Aelitefil, Gluma-Pekalux, light cured glass ionomer cement(Fuji II LC). Each of the materials was applied to the exposed surfaces of 10 teeth by insertion into a cylindrical shaped matrix which is 3mm diameter and 3mm in height. The completed specimens were stored at $37^{\circ}C$ under 100% humidity for 24 hours : the shear bond strength of each material to dentin surface were measured with INSTRON universal testing machine. The results were as follows : 1. Shear bond strength to dentin surface increased in order of light cured glass ionomer cement(Fuji II LC), Gluma, Allbond 2, Scotchbond Multipurpose. 2. Between shear bond strength of light cured glass ionomer cement(Fuji II LC) and Allbond 2, there was statistical significace(p<0.05) 3. Between shear bond strength of light cured glass ionomer cement(Fuji II LC) and Scotchbond Multipurpose, between shear bond strength of Gluma and Scotchbond Multipurpose, there was statistical significance.(p<0.01) The shear bond strength of dentin bonding agents were higher than light cured glass ionomer cement. The reason is that materials and quality of dentin bonding agent were enhanced. Further investigation is necessary to improve shear bond strength of light cured glass ionomer cement.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.06a
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• pp.414-414
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• 2007

In this study, Liquid Crystal (LC) alignment and tilt angle generation in Nematic Liquid Crystal (NLC) with negative dielectric anisotropy on the homeotropic PI surface with new ion beam exposure are reported. Also. high density of ion beam energy (DuoPIGatron type Ar ion gun) is used in this study. The tilt angle of NLC on the homeotropic Polyimide (PI) surface for all incident angles is measured about 38 degree and this has a stabilization trend. And the good LC alignment of NLC on the PI surface with ion beam exposure of $45^{\circ}$ incident angle was observed. Also the tilt angle of NLC on the homeotropic PI surface with ion beam exposure of $45^{\circ}$ had a tendency to decrease as ion beam energy density increase. The tilt angle could be controlled from verticality to horizontality. Also, the LC aligning capabilities of NLC on the homeotropic PI surface according to ion beam energy has the goodness in case of more than 1500 eV. Finally. the superior LC alignment thermal stability on the homeotropic PI surface with ion beam exposure can be achieved. For OCB(Optically Compensated Bend) mode driving, we can need pretilt angles control for fast response time. In this study, We success pretilt angles control. Consequently, this result can be applied for OCB mode.