• Proceedings of the Polymer Society of Korea Conference
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• 2006.10a
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• pp.285-285
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• 2006

The ionic layer-by-layer (LBL) assembled films can be formed by sequentially dipping of substrates to oppositely charged polyions solution in the multilayer, called polyelectrolytes multilayer (PEM) films. Easy way of these assemblies of charged polymers offer the ability to adjust important parameters such as controllability of thickness in the nanometer-scale level and functionality of most top layer of PEM films. Nevertheless, we do not know of any trials to fabricate PEM organic films into nanometer size. Herein, we show the integration of the LBL technique with DPN in fabricating nanometer size patterns of multilayered polyelectrolyte structures. Through the use of single and multiple cantilever AFM probes, we demonstrate the parallel writing capabilities of DPN.

• Bulletin of the Korean Chemical Society
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• v.28 no.12
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• pp.2253-2260
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• 2007

A series of tetra donor substituted [2.2]paracyclophane-based two-photon absorption (TPA) fluorophores were synthesized in neutral and cationic forms. The imaging activity of overall set of fluorophores was studied by the two-photon induced fluorescence (TPIF) method in a range of solvents. We also measured a clear progression toward a longer photoluminescence lifetime with increasing solvent polarity (intrinsic photoluminescence lifetime, τi: ~2 ns in toluene → 12-16 ns in water). The paracyclophane fluorophores with this unique property can be utilized as an optical polarity probe for the biomolecular substrates. The combined measurement of the two-photon fluorescence microscopy (TPM) cell image and TPIF lifetime can give us a better understanding of the biological processes and local environments in the cells.

• Bulletin of the Korean Chemical Society
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• v.31 no.8
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• pp.2190-2194
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• 2010

Development of the methods to organize zeolite microcrystals into closely packed and uniformly aligned monolayers on various substrates have been pursued viewing microparticles as a novel class of building blocks. We now report that the vertically aligned zeolite monolayer can be applied as novel supramolecularly organized systems for anisotropic photoluminescence in high dichroic ratio, to study energy transfer dynamics between the internal and external fluorophores, and to develop zeolite-based advanced materials. Study of polarized fluorescence spectroscopy and angle-dependent intensity change with dye molecules in different surroundings further provides insight into molecular interactions that can be used for the future design of optoelectronic device in nanometer size. In addition, this report shows that isolating of organic dye through surface treatment is crucial for preventing the egress of the incorporated dye molecules from the channels of zeolite to the solution and to enhance the anisotropic luminescence.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.07a
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• pp.185-189
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• 2002

Flexible displays such as plastic based LCDs and organic light-emitting diodes for mobile communication devices have been researched and developed at KETI in KOREA since 1997. The Plastic film substrate has so poor thermal tolerance and non-rigidness that the fabrication of active devices and panel assembly have to perform at low temperature and pressure. In addition, high thermal expansion of the substrate is also a serious problem for reliable metallic film deposition. In this paper, we investigated particularly on the fundamental characteristics of various plastic substrates and then, suggested novel methods that improve the fabrication processes of plastic LCD panel. In order to maintain stable substrate surface and uniform cell gap during panel assembly, we utilized newly-invented iii and vacuum chuck. Electro-optical characteristics of fabricated plastic LCD are better than or equivalent to those of typical glass based LCDs though it is thinner, lighter-weight and more robust.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.07b
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• pp.685-688
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• 2003

[ $(Ba,Sr,Ca)TiO_3$ ] powders, prepared by the sol-gel method, were mixed with an organic vehicle and the BSCT thick films were fabricated by the screen printing techniques on alumina substrates. The grain size decreased with increasing amounts of $MnO_2$, and the BSCT(50/40/10) thick film doped with 1wt% $MnO_2$ showed a value of 6.5mm. The thickness of thick films by four-cycle on printing/drying was approximately 100mm. The relative dielectric constant, dielectric loss and tunability of the BSCT(S0/40/10) thick films doped with 1.0wt% $MnO_2$ were 1296, 0.61% and 11.18%, respectively.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.07b
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• pp.632-635
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• 2003

[ $(Ba,Sr,Ca)TiO_3$ ] powders, prepared by the sol-gel method, were mixed with organic vehicle and the BSCT thick films were fabricated by the screen printing techniques on alumina substrates. The dielectric properties were investigated for various composition ratio and $Nb_2O_5$ doping contents. All the BSCT thick films, sintered at $1420^{\circ}C$, showed the typical XRD patterns of a perovskite polycrystalline structure. The Curie temperature and the relative dielectric constant decreased with increasing Ca content and $Nb_2O_5$ doping amount. The relative dielectric constant, dielectric loss and tunability of the BSCT(50/40/10) thick films doped with 1.0wt% $Nb_2O_5$ were 1410, 0.65% and 17.29% respectively.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.23 no.4
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• pp.343-346
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• 2010

We have investigated growth of CdTe thin films by using (As, GaAs) buffer layers for application of large scale IR focal plane arrays(IFPAs). Buffer layers were grown by molecular beam epitaxy(MBE), which reduced the lattice mismatch of CdTe/Si and prevented native oxide on Si substrates. CdTe thin films were grown by metal organic chemical deposition system(MOCVD). As a result, polycrystalline CdTe films were grown on Si(100) and arsenic coated-Si(100) substrate. In other case, single crystalline CdTe(400) thin film was grown on GaAs coated-Si(100) substrate. Moreover, we observed hillock structure and mirror like surface on the (400) orientated epitaxial CdTe thin film.

• Journal of Environmental Health Sciences
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• v.13 no.2
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• pp.83-90
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• 1987

The objective of this study is to review the basic theories related substrate removal in wastewater flow variations using submerged biofilm reactor. An aerated biofilm reactor is that in which influent organic substrates are aerobically oxidized by the microorganisms of biofilm grown on the surface of submerged media. No sludge is returned, and oxygen is supplied by diffusers. Three types of aerated biofilm reactor are one stage-central aeration, one stageup flow aeration and two stage-side aeration. The orders of substrate removal capacity in wastewater flow variations showed two stage-side aeration, one stage-upflow aeration and one stage-central aeration. The phenonmenon of nonclosing volid in upflow aeration type was superior to these in central-side aeration type. Attached biofilm masses in case of upflow, side and central aeration reactor were 1.0mg/cm$^2$, 4.1 mg/cm$^2$ and 0.93 mg/cm$^2$, respectively. Yield coefficient for biofilm was 0.31 to 0.48. Especially, removal efficiency can be increased remarkably according to the number of biofilm reactor and the packed condition of media.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.18 no.6
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• pp.550-553
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• 2005

[ $Pb(Zr_{0.2}Ti_{0.8})O_3$ ] powders, prepared by the sol-gel method, were mixed with an organic vehicle and the PZT thick films were fabricated by the screen-printing techniques on Pt/alumina substrates. The structural and dielectric properties were examined as a function of sintering temperature. The particle size distribution of the powder is bimodal with the mean particle size of about $1.2\;{\mu}m$. The average grain size of the PZT thick films sintered above $1000^{\circ}C$ was about $3.1\;{\mu}m$ and the thickness of the specimens was approximately $41\;{\mu}m$. The relative dielectric constant and dielectric loss of the thick films sintered at $1050^{\circ}C$ were 337 and $1.24\%$, respectively.

• Journal of the Korean Applied Science and Technology
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• v.11 no.2
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• pp.89-92
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• 1994

Ultra thin organic films, (3-docosyl benzimidazolium)-TCNQ(1:1)complex, were deposited onto ordinary microscope slide glass substrates with a Langmuir-Blodgett technique. II-A isotherms were studied to find optimum conditions of deposition by varying temperature. Anisotropic de electrical conductivities were measured at room temperature. They are about $5.21{\times}10^{-12}S/cm$ along the direction of film surface, and $(2.73{\sim}4.40){\times}10^{-16}S/cm$ in the vertical direction.