• Journal of the Korean Ceramic Society
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• v.49 no.5
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• pp.427-431
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• 2012

The $TiO_2$ foam synthesized using freeze-casting is a promising photocatalyst and photovoltaic electrode for a variety of energy applications, because the freeze-casting technique is easy to use, cheap, and suitable for mass-production. Despite its several advantages, little scientific information is available on the processing and morphology of the $TiO_2$ foams processed by freeze-casting. In particular, no systematic study has been performed on the microstructural evolution and morphological change of the rutile-phase $TiO_2$ foams during sintering. Therefore, in the present study, several $TiO_2$ foam samples were produced using the freeze-casting technique, which were then sintered at a relatively high temperature of $1200^{\circ}C$ for 1, 2, and 4 h to compare the morphological changes in the microstructure and to understand the effects of processing parameters of the rutile-phase $TiO_2$ foams. The foam ligament size increased near linearly with increasing sintering time whereas the average pore size decreased only slightly with increasing sintering time, with changes in particle morphology from sphere to rod and complete phase transformation from anatase to rutile.

• Fashion & Textile Research Journal
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• v.10 no.2
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• pp.254-259
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• 2008

Poly(ethylene-co-vinylacetate)(EVA) microspheres were prepared by a thermally induced phase separation. The microsphere formation occurred by the nucleation and growth mechanism in the metastable region. The diluents used were toluene. The microsphere formation and growth was followed by the cloud point of the optical microscope measurement. The microsphere size, which was obtained by SEM observation and particle size analyzer, became decreased when the titanium dioxide($TiO_2$) concentration was higher. The deodorizing function of the prepared fabrics was studied by the determination of the decomposing capability for $NH_3$. The deodorant activity of these deodorizing fabrics was measured by chromogenic gas detector tubes. The deodorant activity of $NH_3$ increased with increasing $TiO_2$ concentration of EVA microsphere.

• Korean Journal of Materials Research
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• v.24 no.1
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• pp.33-36
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• 2014

This study was aimed at synthesizing and characterizing cerium-doped titania. Cerium-doped anatase titania powders were prepared by sol-gel process, with ammonium (IV) nitrate and titanium (IV) butoxide as the raw materials. The characteristics of pure $TiO_2$ and cerium-doped $TiO_2$ were investigated by XRD, TG/DTA, FE-SEM, and UV-vis spectroscopy. The results of this study show that anatase type of $TiO_2$ was obtained in as-prepared and calcined $TiO_2$ and Ce-$TiO_2$ powder. A DTA curve was also observed as the crystallization temperature decreased with increasing cerium contents. We found that the crystallite size of the obtained anatase particles decreased from 55 nm to 25 nm and the particle size decreased with increasing cerium contents. Moreover, UV-vis spectra showed that anatase titania powders with various cerium contents effectively extend the light absorption properties to the visible region.

• Imaging Science in Dentistry
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• v.51 no.4
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• pp.363-372
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• 2021

Purpose: This systematic review and meta-analysis assessed the diagnostic accuracy of imaging examinations for the detection of peri-implant bone defects and compared the diagnostic accuracy between titanium (Ti) and zirconium dioxide (ZrO₂) implants. Materials and Methods: Six online databases were searched, and studies were selected based on eligibility criteria. The studies included in the systematic review underwent bias and applicability assessment using the Quality Assessment of Diagnostic Accuracy Studies 2 (QUADAS-2) tool and a random-effect meta-analysis. Summary receiver operating characteristic (sROC) curves were constructed to compare the effect of methodological differences in relation to the variables of each group. Results: The search strategy yielded 719 articles. Titles and abstracts were read and 61 studies were selected for full-text reading. Among them, 24 studies were included in this systematic review. Most included studies had a low risk of bias (QUADAS-2). Cone-beam computed tomography (CBCT) presented sufficient data for quantitative analysis in ZrO₂ and Ti implants. The meta-analysis revealed high levels of inconsistency in the latter group. Regarding sROC curves, the area under the curve (AUC) was larger for the overall Ti group (AUC=0.79) than for the overall ZrO₂ group (AUC=0.69), but without a statistically significant difference between them. In Ti implants, the AUCs for dehiscence defects(0.73) and fenestration defects(0.87) showed a statistically significant difference. Conclusion: The diagnostic accuracy of CBCT imaging in the assessment of peri-implant bone defects was similar between Ti and ZrO₂ implants, and fenestration was more accurately diagnosed than dehiscence in Ti implants.

• Bulletin of the Korean Chemical Society
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• v.22 no.11
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• pp.1213-1216
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• 2001

1,2-Diketones, camphorquinone and 1-phenyl-1,2-propanedione, are converted to the corresponding $\alpha-hydroxyketones$ in moderate to good yields by TiO2-catalyzed photochemical reactions in deoxygenated alcoholic media. The reduction yield for 1-phenyl-1,2-propanedione is considerably increased by addition of water or triethylamine

• Journal of Sensor Science and Technology
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• v.31 no.2
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• pp.102-106
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• 2022

Currently, the demand for real-time monitoring of water quality has increased dramatically. Total organic carbon (TOC) analysis is a suitable method for real-time analysis compared with conventional biochemical oxygen demand (BOD) and chemical oxygen demand (COD) methods in terms of analysis time. However, this method is expensive because of the complicated internal processes involved. The photocatalytic titanium dioxide (TiO2)-based TOC method is simpler as it omits more than three preprocessing steps. This is because it reacts only with organic carbon (OC) without extra processes. We optimized the rate between the TiO2 photocatalyst and binder solution and the TiO2 concentration. The efficiency was investigated under 365 nm UV exposure onto a TiO2 coated substrate. The optimized conditions were sufficient to apply a real-time monitoring system for water quality with a short reaction time (within 10 min). We expect that it can be applied in a wide range of water quality monitoring industries.

• Applied Science and Convergence Technology
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• v.24 no.6
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• pp.219-223
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• 2015

Enhancement of the surface hydrophobicity of polydimethylsiloxane (PDMS) thin films deposited on substrates covered with titanium dioxide ($TiO_2$) nanospheres was studied. First, a low-temperature solution-phase method using polyvinylpyrrolidone (PVP) as a surface capping agent and a water/dimethylformamide (DMF) mixture as the reaction medium was used to synthesize monodisperse $TiO_2$ nanospheres. It was possible to easily control hydrolysis rate of the Ti-precursors and the size of the synthesized nanospheres by varying the amount of PVP and the volume ratio of the solvent mixture. Spray coating of the synthesized $TiO_2$ nanospheres under the PDMS film increased the water contact angle of the film surface to $150.3^{\circ}$. This simple treatment can modify the surface morphology at a nanometer scale without any long or complicated nanoprocess; hence, the surface enters the superhydrophobic Cassie-Baxter regime.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.199-200
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• 2007

본 논문에서는 $SiO_2$ Gate 유전체를 대체할 재료의 하나인 $TiO_2$, Gate 유전체의 기판 증착 온도에 따른 특성을 알아보고자 한다. 디바이스의 고집적화가 높아짐에 따라 얇은 두께의 Gate 유전체의 절대적인 필요에 따라 두께를 최소화하면서 유전율은 높아 전기적 특성이 우수한 소재를 찾게 되었다. 본 논문의 실험에서는 비휘발성 메모리 소자 제작시 Gate Blocking Layer 적용을 위해 High-k 물질인 $TiO_2$, 박막 증착 실험을 하였고, APCVD 방법을 사용하여 성장하였다. 증착 온도에 따른 I-V 특성을 분석하고 그에 따른 소자의 물리적 구조를 SEM을 통해 확인하면서 소자 제작시 최적의 온도를 찾고자 하였다.

• Membrane Journal
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• v.21 no.2
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• pp.193-200
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• 2011

An amphiphilic graft copolymer comprising a poly(vinyl chloride) (PVC) backbone and poly (styrene sulfonic acid) (PSSA) side chains (PVC-g-PSSA) was synthesized via atom transfer radical polymerization (ATRP). Mesoporous titanium dioxide $(TiO_2)$ films with crystalline anatase phase were synthesized via a sol-gel process by templating PVC-g-PSSA graft copolymer. Titanium isopropoxide (TTIP), a $TiO_2$ precursor was selectively incorporated into the hydrophilic PSSA domains of the graft copolymer and grew to form mesoporous $TiO_2$ films, as confirmed by scanning electron microscopy (SEM) and X-ray diffraction (XRD) analysis. The performances of dye-sensitized solar cell (DSSC) were systematically investigated by varying spin coating times and the amounts of P25 nanoparticies. The energy conversion efficiency reached up to 2.7% at 100 mW/$cm^2$ upon using quasi-solid-state polymer electrolyte.

• Journal of Surface Science and Engineering
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• v.52 no.4
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• pp.187-193
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• 2019

Electroless Ni-P coatings are widely used in the chemical, mechanical, and electronic industries because of their excellent wear and abrasion resistance. In this study, the effect of $TiO_2$ particles of composite coating was investigated. To improve the corrosion resistance, electroless $Ni-P-TiO_2$composite coating was studied by varying the $TiO_2$ content. The morphology and phase structure of $Ni-P-TiO_2$ composite coatings were analyzed by scanning electron microscopy(SEM), X-ray diffractometry(XRD) and X-ray photoelectron spectroscopy(XPS). The result showed that $Ni-P-TiO_2$composite coating is composed of Ni, P, Ti and O. It exhibits an amorphous structure, high hardness and good corrosion resistance to the substrate. $Ni-P-TiO_2$ composite coatings have higher open circuit potential than that of the substrate, which obtained at $TiO_2$ content of 5.0 g/L optimal integrated properties.