• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1998.11a
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• pp.339-342
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• 1998

Ferroelectric L $a_2$ $Ti_2$ $O_{7}$(LTO) thin films were prepared by chemical solution deposition processes. Acetylacetone was used as chelating agent and nitric acid was added in the stock solution to control hydrolysis and condensation reaction rate. The LTO thin films were spin-coated on Pt/Ti/ $SiO_2$/(100)Si and Pt/Zr $O_2$/ $SiO_2$/(100)Si substrates. After multiple coating, dried thin films were heat-treated for decomposition of residual organics and crystallization. The role of acetylacetone in Ti iso-propoxide stabilization by possibly substituting $O^{i}$Pr ligand was studied by H-NMR. B site-rich impurity phase, i.e. L $a_4$ $Ti_{9}$ $O_{24}$, was found after annealing, where its appearance was dependent on process temperature indicating the possible reaction with substrate. Dielectric and other relevant electrical properties were measured and the results were compared between modified sol-gel and MOD processes.s.s.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.07b
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• pp.861-864
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• 2002

Ferroelectric $Bi_{4-x}Nd_xTi_3O_{12}$(BNdT) thin films with the composition(x=0.75) were prepared on pt/Ti/$SiO_2$/Si(100) substrate by metal-organic deposition. The electrical and structural characteristics of BNdT thin films were investigated to develop ferroelectric thin films for capacitor layers of FRAM. After spin coating, thin films were annealed at $650^{\circ}C$ for 1hour in oxygen atmosphere. Scanning electron micrographs showed uniform surfaces composed of rod-like grains. The $Bi_{4-x}Nd_xTi_3O_{12}$(X=0.75) thin film capacitors with a Pt top electrode showed better ferroelectric properties. At the applied voltage of 5V, the dielectric constant$(\varepsilon_r)$, dissipation factor$(tan{\delta})$, remanent polarization(2Pr) and nonvolatile swiching charge of the $Bi_{4-x}Nd_xTi_3O_{12}$(x=0.75)thin films were about 346.7, 0.095, $56{\mu}C/cm^2$ and $38{\mu}C/cm^2$ respectively. Also the capacitor did not show any significant fatigue up to $8{\times}10^{10}$ read/write switching cycles at a frequency of 1MHz.

• Journal of the Korean Solar Energy Society
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• v.31 no.3
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• pp.67-72
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• 2011

The aim of this study is to evaluate how much would the building energy consumption be saved by applying DSSC BIPV window which is possible to control the transmittance and express the color in the office building. For this, physical characteristics such as transmittance and reflectance, U-factor of DSSC areanalyzed and an annual energy consumption that is connected to dimming control is calculated when DSSC BIPV window is applied by alternate clear window system. As a result, It is possible to reduce the anannual energy consumption as much as4.1% by just change the clear double window system to DSSC BIPV double window system because the major factor to reduce energy consumption in the office that has much cooling load than other building is SHGC. When the thermal insulation properties of DSSC BIPV window with low-e coating and making triple window are improved, energy saving ratio is about 9%. Plus, energy saving ratio of 25~28% in lighting energy consumption is possible when the dimming control system with DSSC BIPV window is adopt.

• Korean Journal of Materials Research
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• v.29 no.12
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• pp.757-763
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• 2019

A stacked high-voltage (900 V) Al electrolytic capacitor made with ZrO₂ coated anode foils, which has not been studied so far, is realized and the effects of Zr-Al-O composite layer on the electric properties are discussed. Etched Al foils coated with ZrO₂ sol are anodized in 2-methyl-1,3-propanediol (MPD)-boric acid electrolyte. The anodized Al foils are assembled with stacked structure to prepare the capacitor. The capacitance and dissipation factor of the capacitor with ZrO₂ coated anode foils increase by 41 % and decrease by 50 %, respectively, in comparison with those of Al anode foils. Zr-Al-O composite dielectric layer is formed between separate crystalline ZrO₂ with high dielectric constant and amorphous Al₂O₃ with high ionic resistivity. This work suggests that the formation of a composite layer by coating valve metal oxide on etched Al foil surface and anodizing it in MPD-boric acid electrolyte is a promising approach for high voltage and volume efficiency of capacitors.

• Macromolecular Research
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• v.15 no.4
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• pp.343-347
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• 2007

Novel composite membranes, which delivered high separation performance for propylene/propane mixtures, were developed by coating inert poly(ethylene-co-propylene) rubber (EPR) onto a porous polyester substrate, followed by the physical distribution of $AgBF_4$. Scanning electron microscopy-wavelength dispersive spectrometer (SEM-WDS) revealed that silver salts were uniformly distributed in the EPR layer. The physical dispersion of the silver salts in the inert polymer matrix, without specific interaction, was characterized by FT-IR and FT-Raman spectroscopy. The high separation performance was presumed to stem from the in-situ dissolution of crystalline silver ionic aggregates into free silver ions, which acted as an active propylene carrier within a propylene environment, leading to facilitated propylene transport through the membranes. The membranes were functional at all silver loading levels, exhibiting an unusually low threshold carrier concentration (less than 0.06 of silver weight fraction). The separation properties of these membranes, i.e. the mixed gas selectivity of propylene/propane ${\sim}55$ and mixed gas permeance ${\sim}7$ GPU, were stable for several days.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.44 no.2
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• pp.29-34
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• 2012

For the purpose of developing liner board for water-resistant corrugated board in the cold chain system, several types of base paper for corrugated board were purchased from the market and 6 different boards were produced in the paperboard mill by applying the chemicals on the base paper. Then, water-moisture resistant performance and physical properties of the boards were compared each other. The liner board which is dried at high temperature with pressure by Condebelt papermaking system(CK paper) showed a superior performance in strength over common liner boards. Strength of the board increased by surface chemical treatment up to 60% of compressive strength and 30% of bursting strength. Starch insolubilization with Ammonium-Zirconium Carbonate(AZC) and surface coating with a surface size and a moisture resistant chemical on CK paper showed the best result. Therefore, this method was recommended to produce the outer liner board for water -resistant corrugated board.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2011.04a
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• pp.339-347
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• 2011

This study was carried out in order to manufacture the high quality coated paper. High quality coated paper includes not only present state but also the state of the future. So in this study, acrylic-styrene emulsion which polymerized in laboratory was compared with SB(Styrene-butadiene) latex during thermal aging. The coated paper with three different formulations which controlled the dosage of acrylic-styrene emulsion were prepared. The coated paper were thermally aged at $105^{\circ}C$ for 18days and the optical properties were measured. Brightness, whiteness and CIE L value were higher during thermal aging with increasing amount of acrylic-styrene emulsion. CIE $a^*$ value was higher and CIE $b^*$ value decreased with increasing amount of acrylic-styrene emulsion. These results indicate that high quality coated paper which has anti -thermal aging property can be manufactured with acrylic-styrene emulsion.

• Applied Science and Convergence Technology
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• v.26 no.3
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• pp.47-49
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• 2017

Photocurrent enhancement has been investigated in monolayer (1L) $MoS_2$ with PbS quantum dots (QDs). A metal-semiconductor-metal (Au-1L $MoS_2$-Au) junction device is fabricated using a standard photolithography method. Considerably improved photo-electrical properties are obtained by coating PbS QDs on the Au-1L $MoS_2$-Au device. Time dependent photoconductivity and current-voltage characteristics are investigated. For the QDs-coated $MoS_2$ device, it is observed that the photocurrent is considerably enhanced and the decay life time becomes longer. We propose that carriers in QDs are excited and transferred to the $MoS_2$ channel under light illumination, improving the photocurrent of the 1L $MoS_2$ channel. Our experimental findings suggest that two-dimensional layered semiconductor materials combined with QDs could be used as building blocks for highly-sensitive optoelectronic detectors including radiation sensors.

• Journal of the Korean Society of Propulsion Engineers
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• v.19 no.5
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• pp.84-90
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• 2015

Titanium alloys has been received an attention due to their excellent specific strength and many other superior properties in the application of components of flying subjects. In this study, Ti-6Al-4V (Ti64 alloy) has been selected in order to evaluate oxidation and degradation behaviors under the exposure of high temperature flame. The alloy has been coated with Al diffusion coating routes. The coated alloys showed an improved oxidation and degradation behaviors. The oxidation and degradation mechanism for the coated and uncoated alloys has been discussed in terms of microstructural observations.

• Journal of Hydrogen and New Energy
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• v.19 no.1
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• pp.35-40
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• 2008

Ni-based amorphous alloy ribbon was prepared by a single-roller melt-spinning technique. Palladium coating was found to enhance significantly the absorption/desorption behavior of hydrogen in amorphous alloy. The hydrogen permeability of a Pd-coated $(Ni_{60}Nb_{40}){_{100-X}}$TaX(x=5, 10) amorphous alloy was examined in the temperature range of $623{\sim}773K$, comparable with those of $Pd_{60}-Cu_{40}$ alloys. The permeated hydrogen flux was increased with increasing the temperature and the difference of hydrogen pressure between the feed side and permeates side of the membrane. The Ni-based amorphous alloys were characterized by X-ray diffractometry(XRD) and differential scanning calorimetry(DSC). The morphology of surface and roughness was observed by using scanning electron microscopy(SEM) and atomic force microscopy(AFM).