• Bulletin of the Korean Chemical Society
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• v.29 no.10
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• pp.1887-1892
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• 2008

Novel poly(aspartic acid) derivatives conjugated with L-lysine moieties and their amphiphilic analogs were synthesized and characterized. The chemical structures of these polymers were confirmed using FT-IR and $^1HNMR$ spectroscopy. The physicochemical properties of amphiphilic copolymers were characterized using an electrophonetic light scattering spectrophotometer (ELS) and transmission electron microscopy (TEM). These results indicated a stable nanoparticle formation within aqueous media. These polymers have potential applications in the pharmaceutical and cosmetic fields as delivery vehicles for bioactive molecules.

• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.1516-1519
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• 2008

We report extremely low doping technology in phosphorescent organic light emitting diodes(PHOLEDs). Highly efficient red PHOLEDs with excellent energy transfer characteristics even under 1 % doping condition have been demonstrated. Results reveal efficient host-dopant system to realize highly efficient PHOLEDs and useful cost saving way by reduction of expensive Ir complex dopants.

• 한국정보디스플레이학회:학술대회논문집
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• 2006.08a
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• pp.1010-1013
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• 2006

To understand the exact charge carrier photogeneration properties of photoactive thin films consisting of a ${\pi}-conjugated$ polymer matrix and a triplet dopant, we prepared two types of polymer, poly(9-vinylcarbazole) (PVK) and poly[9,9-bis(2- ethylhexyl)fluorene-2,7-diyl] (PF2/6) doped with triplet emitters for organic light-emitting diodes (OLED), either iridium(III)fac-tris(2-phenylpyridine) $(Ir(ppy)_3)$ or iridium(III)bis[(4,6-fluorophenyl)- $pyridinato-N,C^2'$]picolinate (FIrpic), as thin film devices by using the conventional method. Those doped film devices, as well as pristine film devices, on ITO substrates were characterized by means of steady state photocurrent measurement for a wide spectral range.

• 한국정보디스플레이학회:학술대회논문집
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• 2003.07a
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• pp.903-906
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• 2003

Doping a small amount of a phosphorescent dye into an organic light-emitting diodes(OLED) can lead to a significant improvement in the device properties. The fluorescent host materials like TAZ, CBP have been used, but have a problem of rapid decay of efficiency at high current densities. To alleviate this problem, phosphorescent host was introduced. The whole configuration of OELD fabricated was ITO/a-NPD(50nm)/Zn $cluster:Ir(ppy)_{3}(30nm)/BCP{(10nm)/Alq_{3}(20nm)$ /Al:Li. The OLED showed high luminance (> 50,000 $cd/m^{2}$ ) and external efficiency(5.7%). At higher current densities, rapid decay of external quantum efficiency or host emission, which was frequently observed in the fluorescent host system, were not observed.

• 한국정보디스플레이학회:학술대회논문집
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• 2003.07a
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• pp.1057-1059
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• 2003

New polyfluorene derivatives, poly[9,9-bis(4' n-octyloxyphenyl)] fluorene (PAPF-8) and poly[9,9-bis(4'-(2",7"-dimethylocyloxy)phenyl)] fluorene (PAPF-10) were synthesized from the monomers, 2,7-dibromo-9,9-bis[4' (2"-ethylhexyloxy)benzene] fluorene and 2,7-dibromo-9,9-bis[4' (2", 7"-dimethyloctyloxybenzene)] fluorene through the Ni(0) mediated polymerization. The copolymers were characterized using FT-IR spectroscopy, UV-vis spectroscopy, TGA, photoluminescence (PL) & electroluminescence (EL) spectroscopy, elementa analysis, and molecular weight studies. The synthesized POPF-8 and POPF-10 showed a pure blue emission without any spectral change upon thermal annealing and EL device operation.

• Fibers and Polymers
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• v.2 no.4
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• pp.184-189
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• 2001

Continuous photografting/crosslinking of polyethyleneglycol dimethacrylate oligomers onto cotton using a water-soluble benzophenone photoinitiator was investigated. Photografting increased with increasing irradiation dose, oligomer concentration and photoinitiator concentration. Maximum grafting efficiency of DM 400 and 600 were 83% and 79%, respectively. the photografting increased the wrinkle resistance of cotton implying surface crosslinking of cotton. bothsurface crosslinking and bulk crosslinking of cotton were accomplished via dual curing of a mixed formulation containing both a thermally curable component (BTCCA/SHP) and a UV-curable component. The wrinkle resistance of the crosslinked cotton was found to be higher when cured by thermal curing due to the facile post-polymerization of the UV active component. The presence of crosslinks in the dually crosslinked cotton was verified with FT-IR and thermogravimetric analysis.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.12 no.5
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• pp.30-35
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• 2013

In order to increase cell efficiency in crystalline silicon solar cell, reduction of light reflection is one of the essential problem. Until now silicon wafer was textured by wet etching process which has random patterns along crystal orientation. In this study, high aspect ratio patterns are manufactured by nano imprint process and reflectance could be minimized under 1%. After that, screen printed solar cell was fabricated on the textured wafer and I-V characteristics was measured by solar simulator. Consequently cell efficiency of solar cell fabricated using the wafer textured by nano imprint process increased 1.15% than reference solar cell textured by wet etching. Internal quantum efficiency was increased in the range of IR wave length but decreased in the UV wavelength. In spite of improved result, optimization between nano imprinted pattern and solar cell process should be followed.

• Journal of the Korean Ceramic Society
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• v.47 no.4
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• pp.269-275
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• 2010

In this study, we successfully prepared CNT/$TiO_2$, Pt/CNT and Pt/CNT/$TiO_2$ composites and investigated their photocatalytic activity in MB solution by irradiation under UV light. Fourier transform infrared (FT-IR) spectroscopy was used to characterize the functional group on the surface of MWCNTs, which oxidized by MCPBA. Brunauer-Emmett-Teller (BET) surface area, transmission electron microscopy (TEM), X-ray diffraction (XRD) and energy dispersive X-ray (EDX) were used to analyze the prepared composites. The results of the decomposition of the MB solution indicated that the Pt/CNT/$TiO_2$ composite had the best photocatalytic activity among the three kinds of composites.

• Journal of Pharmaceutical Investigation
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• v.40 no.4
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• pp.219-223
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• 2010

The hyaluronic acid (HA) conjugate bearing $\alpha$-cyclodextrin ($\alpha$-CD) was synthesized as the potential carrier of poly(ethylene glycol) (PEG)-drug conjugates. The HA conjugate was prepared by the reaction between the carboxylic acid of HA and the primary amine of $\alpha$-CD in the presence of 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide and 1-hydroxybenzotriazole. The chemical structure of the conjugate was confirmed using $^1H$ NMR and FT-IR spectroscopy. The conjugate could form nano-sized particles in the presence of PEG by forming the inclusion complexes between $\alpha$-CD at the backbone of HA, which was demonstrated using electrophoretic light scattering and field emission transmission electron microscopy. It is anticipated that this novel kind of nanoparticles can serve as a useful delivery system for PEGylated drugs.

• Textile Coloration and Finishing
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• v.14 no.2
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• pp.77-77
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• 2002

Cotton fabrics dipped in cationic agent(3-chloro-2-hydroxypropyl trimethyl ammonium chloride) were irradiated with deep Ultra Violet Rays(UV), in the region of UV-C using the low pressure mercury lamp. The chemical changes of cationized cotton fabric surfaces were investigated by FT-IR analysis. The dyeabilities of the irradiated portions were investigated by dyeing with acid dyes. Deep UV(UV-C) irradiation broke O-H bonds in cotton fiber and oxidized the fibers. The dyeability of the UV irradiated portion were different from that of the portion not irradiated. Various pattern were gained from one bath dig dyeing by pattern mask. The tensile strengths of cotton fabrics were decreased in the UV irradiated portion. Washing fastness of cotton dyeings were good about 3∼4 grade and light fastness were fair about 2∼3 grade.