• Proceedings of the Korean Vacuum Society Conference
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• 2011.08a
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• pp.376-376
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• 2011

I-III-VI2 chalcopyrite compounds, particularly copper, indium, gallium selenide(Cu(InxGa1-x)Se2, CIGS), are effective light-absorbing materials in thin-film solar application. They are direct band-gap semiconductors with correspondingly high optical absorption coefficients. Also they are stable under long-term excitation. CIS (CIGS) solar cell reached conversion efficiencies as high as 19.5%. Several methods to prepare CIS (CIGS) absorber films have been reported, such as co-evaporation, sputtering, selenization, and electrodeposition. Until now, co-evaporation is the most successful technique for the preparation of CIS (CIGS) in terms of solar efficiency, but it seems difficult to scale up. CIS solar cells have been hindered by high costs associated with a fabrication process. Therefore, inorganic colloidal ink suitable for a scalable coating process could be a key step in the development of low-cost solar cells. Here, we will present the preparation of CIS photo absorption layer by a solution process using novel metal precursors. Chalcopyrite copper indium diselenide (CuInSe2) nanocrystals ranging from 5 to 20nm in diameter were synthesized by arrested precipitation in solution. For the fabrication of CIS photo absorption layer, the CuInSe2 colloidal ink was prepared by dispersing in organic solvent and used to drop-casting on molybdenum substrate. We have characterized the nanoparticless and CIS layer by XRD, SEM, TEM, and ICP.

• Journal of Sericultural and Entomological Science
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• v.37 no.2
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• pp.142-153
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• 1995

This study is undertaken to investigate proper condition and dissolution method of silk fibroin to use it functional material as powder or membrane. Silk fibroin was dissolved with calcium chloride ethanol aqueous solution and hydrochloric acid. When silk fibron was dissolved with calcium chloride ehanol aqueous solution, main chain of silk fibroin was degradaded and molecular conformation was changed. Silk fibroin powder was made from silk fibroin solution. It showed lower thermal decomposition temperature and crystallinity than those of native silk fibroin. And Its molecular conformation was random coil structure. By acid gydrolysis, main chain of silk fibroin was attacked randomly. Silk fibroin powder from hydrolysate showed high crystallinity and thermal decomposition temprature. $\beta$-form molecular conformation was found by IR and X-ray diffraction. Silk fibroin powder form dissolved part with hydrochloric acid showed low thormal decomposition temperature but high crystallinity. During acid hydrolysis, transition of molecular structure of silk fibroin occurred, and it changed to $\alpha$-helix. Silk fibroin film was achieved by casting silk fibroin solution by ehanol solution or saturated vapor treatment, and its molecular conformation changed to $\beta$structure.

• Polymer(Korea)
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• v.32 no.5
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• pp.478-482
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• 2008

The effect of 1,3-dioxolane on the structural development in the optical polycarbonate film was studied. The 1,3-dioxolane was used as an environmental friendly solvent for manufacturing solution-cast polycarbonate film instead of methylene chloride. The evaporation rate in film drying process decreased due to the high boiling temperature of 1,3-dioxolane. This caused the crystallization in the polycarbonate film. As a result, The increase of crystallinity and roughness led to the decrease of light transmissivity. It was also found that the lowering of mechanical properties in polycarbonate film was attributed to the morphological change due to the solvent evaporation rate in film drying process.

• Analytical Science and Technology
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• v.19 no.5
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• pp.389-393
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• 2006

The detector consisted of ZnS(Ag) scintillator and photomultiplier tube (PMT) is widely used as contamination monitor in the nuclear facilities. Such detectors are mainly manufactured by adhering the ZnS(Ag) powder onto the transparent plastic. In this study the preparation condition for ZnS(Ag) scintillator sheet using a simple method was established. The scintillator sheet was composed with a support polymer sheet and ZnS(Ag) scintillator layer. The base sheet was prepared by casting the polymer solution after solving the polymer with solvent and the scintillator layer was manufactured by printing the mixture solution with ZnS(Ag) and paste. It was found that the polysulfone(PSf) as a polymer for the base sheet and a cyano resin as a paste for adhering the ZnS(Ag) scintillator was suitable. Also, the prepared thin scintillator sheet had a sufficient mechanical strength, a optical transparency and an alpha-ray detection performance.

• Fibers and Polymers
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• v.5 no.3
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• pp.198-203
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• 2004

Composite films were prepared by casting the solution of polyacrylonitrile (PAN) and single wall nanotube (SWNT) in DMF subsequent to sonication. The SWNTs in the films are well dispersed as ropes with 20-30 nm thickness. Moreover, AFM surface image of the composite film displays an interwoven fibrous structure of nanotubes which may give rise to conductive passways and lead to high conductivity. The polarized Raman spectroscopy is an ideal characterization technique for identification and the orientation study of SWNT. The well-defined G-peak intensity at 1580 $cm^{-1}$shows a dependency on the draw ratio under cross-Nicol. The degree of nanotube orientation in the drawn film was measurable from the sine curve obtained by rotating the drawn film on the plane of cross-Nicol of polarized Raman microscope. The threshold loading of SWNT for electrical conductivity in PAN is found to be lower than 1 wt% in the composite film. The electrical conductivity of the SWNT/PAN composite film decreased with increasing of draw ratio due to the collapse of the interwoven fibrous network of the nanotubes with uniaxial orientation.

• Korean Journal of Metals and Materials
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• v.47 no.2
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• pp.129-137
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• 2009

Corrosion behaviors of TiN coated dental casting alloys have been researched by using various electrochemical methods. Three casting alloys (Alloy 1: 63Co-27Cr-5.5Mo, Alloy 2: 63Ni-16Cr-5Mo, Alloy 3: 63Co-30Cr-5Mo) were prepared for fabricating partial denture frameworks with various casting methods; centrifugal casting(CF), high frequency induction casting(HFI) and vacuum pressure casting(VP). The specimens were coated with TiN film by RF-magnetron sputtering method. The corrosion behaviors were investigated using potentiostat (EG&G Co, 263A. USA) in 0.9% NaCl solution at $36.5{\pm}1^{\circ}C$. The corrosion morphologies were analyzed using FE-SEM and EDX. Alloy 1 and Alloy 2 showed the ${\alpha}-Co$ and ${\varepsilon}-Co$ phase on the matrix, and it was disappeared in case of TiN coated Alloy 1 and 2. In the Alloy 3, $Ni_2Cr$ second phases were appeared at matrix. Corrosion potentials of TiN coated alloy were higher than that of non-coated alloy, but current density at passive region of TiN coated alloy was lower than that of non-coated alloy. Pitting corrosion resistances were increased in the order of centrifugal casting, high frequency induction casting and vacuum pressure casting method from cyclic potentiodynamic polarization test.

• Composites Research
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• v.28 no.2
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• pp.40-45
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• 2015

The purpose of the present work was to preparation and study of full biodegradable Eco-friendly bio-composites by using renewable resources. In this study, wheat protein isolate (WPI) films were formed by cross linking with resorcinol through solution casting method for packaging applications. By varying the resorcinol content (10, 20, 30, 40, and 50 wt %), its effect on mechanical properties of the wheat protein isolate film was measured. The addition of 20% resorcinol led to an overall increase in the tensile strength from 5.2 to 18.6 MPa and modulus increase from 780 to 1132 MPa than WPI films. The % elongation was increased from 2.8 to 9.05 when compared to unmodified WPI film. A thermal phase transition of the prepared WPI was assessed by means of DSC. FTIR is evident that the characteristic WPI spectral IR bands shifted on cross-linking with resorcinol.

• Carbon letters
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• v.15 no.1
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• pp.50-56
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• 2014

We prepared ethylene vinyl alcohol (EVOH)/graphene oxide (GO) membranes by solution casting method. X-ray diffraction analysis showed that GOs were fully exfoliated in the EVOH/GO membrane. The glass transition temperatures of EVOH were increased by adding GOs into EVOH. The melting temperatures of EVOH/GO composites were decreased by adding GOs into EVOH, indicating that GOs may inhibit the crystallization of EVOH during non-isothermal crystallization. However, the equilibrium melting temperatures of EVOH were not changed by adding GOs into EVOH. The oxygen permeability of the EVOH/GO (0.3 wt%) film was reduced to 63% of that of pure EVOH film, with 84% light transmittance at 550 nm. The EVOH/GO membranes exhibited 100 times better (water vapor)/(oxygen) selectivity performance than pure EVOH membrane.

• Macromolecular Research
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• v.17 no.9
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• pp.697-702
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• 2009

Mesoporous ethanesilica thin film was prepared using PEO-PLGA-PEO triblock copolymers as structure-directing agents and (1,2-bis(triethoxysilyl) ethane BTESE; bridged organosilicates) as inorganic precursors via one-step sol-gel condensation of ethanesilica precursors. The mesostructure of ethanesilica films is critically dependent on the processing experimental parameters after the hydrolyzed silica sol mixture was spin-cast. This study examined the effects of the block copolymer template/organosilica precursor ratio in the casting solution and aging period before calcination of the mesostructure. It was further demonstrated that mesoscopic ordering of organosilicate thin films is induced by the rearrangement of block copolymer template/organosilica hybrid during thermal decomposition of the PEO-PLGA-PEO triblock copolymer. The mesoporous structure and morphology were characterized by SAXS, TEM and solid-state NMR measurement.

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.568-570
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• 2009

Octadecyltrichlorosilane (OTS) self-assembled monolayer was selectively patterned by deep ultraviolet exposure, resulting in differential surface state, hydrophilic area with OTS hydrophobic surroundings. High-resolution (<10 ${\mu}m$) nanoparticulate Ag electrodes and organic semiconductors were patterned from simple dip-casting and ink-jetting on the pre-patterned hydrophilic surface, forming all solution-processed organic thin film transistors. The devices typically have shown a mobility of 0.065 $cm^2/V{\cdot}s$ and on-off current ratio of $8{\times}10^5$.