• Journal of the Korean Vacuum Society
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• v.15 no.2
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• pp.173-179
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• 2006

We have investigated structural and electrical properties of $PbZr_{0.3}Ti_{0.7}O_{3}$ (PZT) thin films deposited by pulsed laser deposition methods. PZT thin films have been deposited on $LaMnO_3$ (LMO) bottom electrodes with $LaAlO_3$ (LAO) substrates during different deposition times. High-resolution x-ray diffraction data have shown that all the PZT films and bottom electrodes are highly oriented. The thickness of each film is determined by field-emission scanning electron microscope. We have also observed root mean square roughness by using atomic force microscopy mode, and local polarization distribution and retention behavior of a ferroelectric domain by using piezoelectric force microscopy mode. A PZT/LMO structure has shown good ferroelectric and retention properties as the media for nano-storage devices.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.62-62
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• 2008

As micro-system move toward higher speed and miniaturization, requirements for embedding the passive components into printed circuit boards (PCBs) grow consistently. They should be fabricated in smaller size with maintaining and even improving the overall performance. Miniaturization potential steps from the replacement of surface-mount components and the subsequent reduction of the required wiring-board real estate. Among the embedded passive components, capacitors are most widely studied because they are the major components in terms of size and number. Embedding of passive components such as capacitors into polymer-based PCB is becoming an important strategy for electronics miniaturization, device reliability, and manufacturing cost reduction Now days, the dielectric films deposited directly on the polymer substrate are also studied widely. The processing temperature below $200^{\circ}C$ is required for polymer substrates. For a low temperature deposition, bismuth-based pyrochlore materials are known as promising candidate for capacitor $B_2Mg_{2/3}Nb_{4/3}O_7$ ($B_2MN$) multi layers were deposited on Pt/$TiO_2/SiO_2$/Si substrates by radio frequency magnetron sputtering system at room temperature. The physical and structural properties of them are investigated by SEM, AFM, TEM, XPS. The dielectric properties of MIM structured capacitors were evaluated by impedance analyzer (Agilent HP4194A). The leakage current characteristics of MIM structured capacitor were measured by semiconductor parameter analysis (Agilent HP4145B). 200 nm-thick $B_2MN$ muti layer were deposited at room temperature had capacitance density about $1{\mu}F/cm^2$ at 100kHz, dissipation factor of < 1% and dielectric constant of > 100 at 100kHz.

• Journal of the Korean Electrochemical Society
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• v.5 no.2
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• pp.43-46
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• 2002

Commercial titanium rod was anodized in three types of electrolytes such as 0.06 mol/L $\beta-glycerophosphate+0.3mol/L$ calcium acetate, 0.06mol/L $\beta-glycerophosphate+0.3mol/L$ sodium acetate and 0.06 mol/L $\beta-glycerophosphate+5mol/L$ calcium phosphate. The titanium oxide layer $(TiO_2)$ was characterized by scanning electron microscope (SEM), X-ray diffraction (XRD) and electron spectroscopy chemical analysis (ESCA). Numerous micropores were observed on the titanium oxide layer by SEM. The diameter of micropores increased with the increase of electrolytic voltage. The titanium oxide layer was composed of anatase structure. The phosphorous element was detected at 130 eV binding energy, but calcium was not found in the oxide layer because of lower contents. After anodizing the oxide layer was etched in the 30g/L NaOH solution at $80^{\circ}C$ for 1hr. The surroundings of micropores were much more smoothed and rounded than before alkaline etching.

• Mycobiology
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• v.48 no.5
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• pp.383-391
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• 2020

Use of nanoparticles (NPs) in several commercial products has led to emergence of novel contaminants of air, soil and water bodies. The NPs may exhibit greater ecotoxicity due to nano-scale dependent properties over their bulk counterparts. The present investigation explores the effect of in vitro supplementation of TiO₂, silica and silver NPs on radial growth and ultrastructural changes in the hyphae and spores of two mushroom genera, Ganoderma lucidum and Volvariella volvaceae. A concentration dependent decrease in radial growth on NP amended potato dextrose agar medium was recorded. However, in comparison to control, there was decrease in radial diameter on supplementation with TiO₂ NPs while an increase was recorded for silica and silver NPs amendments as compared to their bulk salts at same concentrations after 48 h of incubation. Optical microscopy studies showed decrease in the number of spores while increase in spore diameter and thinning of hyphal diameter on NPs supplementation. Scanning electron microscopy analysis of fungal growth showed presence of deflated and oblong spores in two fruiting strains of Ganoderma while Volvariella exhibited decreased sporulation. Further, hyphal thinning and branching was recorded in response to NP amendments in both the test mushrooms. Enhancement of protein content was observed on NP compared to bulk supplementation for all cultures, concentrations and hours of incubation except for TiO₂ NPs. Likewise, bulk and NP supplementations (at 100 mg L^-1) resulted in enhanced laccase activity with occurrence of laccase specific protein bands on SDS-PAGE analysis.

• Applied Chemistry for Engineering
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• v.18 no.1
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• pp.17-23
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• 2007

For the purpose of antibacterial and photocatalystic deodorization functions, the papermaking inorganic fillers and pigments were surface-modified with Ag nano-colloidal solution and $TiO_2$ by using the hybridization technique. The functional specialty sheets and coating papers were produced with the surface-modified fillers and pigments, and evaluated by halo test and inhibition growth test in their antibacterial and photocatalystic characteristics. For the application of specially produced antibacterial handsheet to the wallpaper usages, the photocatalyst efficiency test of benzene in volatile organic compound dissolution experiment of antibacterial and deodorization function wallpaper showed that the efficiency was 45~50% for 80 min of reaction time and 90% of attained resolution was reached at approximately 30 min of response time.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.11a
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• pp.691-694
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• 2004

염료감응형 태양전지는 다공질 $TiO_2$ 전극막, 광감응형 염료, 전해질, 상대전극으로 구성된, 전기화학적 원리를 응용한 신형태양전지이다. 염료감응형 태양전지의 상대전극으로 주로 Pt가 사용되고 있는데 본 연구에서는 탄소나노튜브를 사용하여 상대전극으로서의 가능성을 조사하였다. 제조된 탄소나노튜브 상대전극은 cyclic voltammetry와 Impedance spectroscopy을 이용하여 전기화학적 특성을 측정하였다. 또한 탄소 나노튜브 상대 전극이 태양전지의 효율 및 그 특성에 미치는 영향을 알아보기 위하여 단위 셀 태양전지를 제조하여 단파장 하에서의 광전특성을 측정하고, 이를 바탕으로 탄소나노튜브의 상대전극으로서의 가능성을 제시하였다.

• Bulletin of the Korean Chemical Society
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• v.34 no.9
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• pp.2765-2768
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• 2013

The effect of $TiO_2$ nanorods (TNR) and nanoparticles (TNP) composite photoelectrodes and the role of TNR to enhance the energy conversion efficiency in dye-sensitized solar cells (DSSCs) was investigated. The 5% TNR content into the TNP photoelectrode significantly increased the short-circuit current density ($J_{sc}$) and the open-circuit potential ($V_{oc}$) with the overall energy conversion efficiency enhancement of 13.6% compared to the pure TNP photoelectrode. From the photochemical and impedemetric analysis, the increased $J_{sc}$ and $V_{oc}$ for the 5% TNR/TNP composite photoelectrode was attributed to the scattering effect of TNR, reduced electron diffusion path and the suppression of charge recombination between the composite photoelectrode and electrolyte or dye.

• YAKHAK HOEJI
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• v.59 no.3
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• pp.113-119
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• 2015

Protein phosphorylation is one of most important post-translational modifications (PTMs) and plays an important role in regulation of protein function. Here we develop a method for a global identification of phosphopeptides and phosphorylation sites using nano-LC MS/MS. We compared two separation methods, C4 and strong cation ion exchange (SCX). Before phosphopeptides enrichment with $TiO_2$, total proteins from Rat 1 cells have been separated using C4 column or tryptic peptides of proteins from the cells have been separated using SCX column. Finally, we have detected 52 phosphorylation sites on 41 proteins from SCX method and 375 phosphorylation sites on 252 proteins from C4 method, and determined the function and localization of identified phosphoproteins using DAVID software. In particular, we showed new phosphorylation sites from membrane proteins related to various cell signaling mechanisms. This method may contribute to study global signal networks induced by various signals including ligands and drugs.

• Proceedings of the KIEE Conference
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• 1997.11a
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• pp.291-293
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• 1997

In this study, Sol-Gel derived $(Ba_{0.7}Sr_{0.3})TiO_3$ thin films were fabricated and investigated. The stock solution was synthesized and spin-coated on Pt/Ti/$SiO_2$/Si substrate at 4000(rpm] and then, annealed at $650{\sim}750[^{\circ}C]$. Crystallization condition, microstructural properties and interfacial structure were observed by XRD, AFM, SEM and TEM. It was found that the BST thin films were completely crystallized at 750[$^{\circ}C$] and showed nano-sized grains. The dielectric constant and loss of the BST thin films were 220, 0.01 at 1[kHz] respectively. Increasing the temperature, the dielectric constant and loss characteristics were not varied widely. At the applied voltage of 1.5[V], the leakage current density was under the $10^{-9}[A/cm^2]$.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.1
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• pp.114-118
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• 2011

Dye-Sensitized Solar Cells(DSSCs) consist of a titanium dioxide($TiO_2$) nano film of the photo electrode, dye molecules on the surface of the $TiO_2$ film, an electrolyte layer and a counter electrode. But two transparent conductive oxide(TCO) substrates are estimated to be about 60[%] of the total cost of the DSSCs. Currently novel TCO-less structures have been investigated in order to reduce the cost. In this study, we suggested a TCO-less DSSCs which has titanium double layer electrodes. Titanium double layer electrodes are formed by electron-beam evaporation method. Analytical instruments such as electrochemical impedance spectroscopy, scanning electron microscope were used to evaluate the TCO-less DSSCs. As a result, the proposed structure decreases energy conversion efficiency and short-circuit current density compared with the conventional DSSCs structure with FTO glass, while internal series impedance of TCO-less DSSCs using titanium double layer electrodes decreases by 27[%]. Consequently, the fill factor is improved by 28[%] more than that of the conventional structure.