• Bulletin of the Korean Chemical Society
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• 제25권5호
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• pp.634-638
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• 2004

Titanium silicalite-1 (TS-1) molecular sieve was produced by microwave heating of amorphous titanium-containing solid precursors after impregnation with aqueous TPAOH solution. $SiO_2-TiO_2$ xerogel, sub-micron sized $SiO_2-TiO_2$ prepared by thermal plasma process, and Ti-containing mesoporous silica, Ti-HMS, were tested as the solid phase substrates. Highly crystalline product was obtained within 30 min. after microwave irradiation with yields over 90% using $SiO_2-TiO_2$ xerogel, which showed essentially identical physicochemical properties to TS-1 prepared by conventional hydrothermal method. Excellent catalytic activity was also obtained for 1-hexene epoxidation using $H_2O_2.\;SiO_2-TiO_2$ particles prepared by thermal plasma and Ti-HMS were found inferior as a substrate for TS-1, probably due to difficulties in wetting the surface uniformly with TPAOH.

• 한국전기전자재료학회논문지
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• 제30권12호
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• pp.788-793
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• 2017

Electrical behaviors of plasma-sprayed $Al_2O_3-TiO_2$ coatings have been investigated in terms of their $TiO_2$ content. On increasing the $TiO_2$ content from 6 to 30 wt%, the DC electrical conductivity increased by several orders of magnitude. From impedance spectroscopy analysis, the total conductivity of the grains and grain boundaries and their respective activation energies were determined without the electrode effects that could impede ionic transfer. An electron transference number was also estimated, ranging between 6.5% and 7.3% for 13 wt% $TiO_2$ and between 0.4% and 0.7% for 30 wt% $TiO_2$ in the coating. Because of the high electronic contribution to the total conductivity, the $Al_2O_3-TiO_2$ coating could be a new candidate material to obtain superior electrical conductivity as well as corrosion and wear resistances.

• 동력기계공학회지
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• 제19권5호
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• pp.12-16
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• 2015

$TiO_2$ nanoparticle can be used for the improvement of performance of the epoxy resin composites. In this study, the effect of the size of $TiO_2$ nanoparticle on the mechanical properties for the epoxy resin composites was investigated. The size of $TiO_2$ nanoparticle was easily controlled by heat treatment. The heat treatment of $TiO_2$ nanoparticle was conducted between $700^{\circ}C$ and $900^{\circ}C$. The obtained size of $TiO_2$ nanoparticle was 20 nm, 100 nm and 200 nm respectively. As the diameter of $TiO_2$ nanoparticle is smaller, the epoxy resin composite specimen showed higher tensile strength. It was also found that Vickers hardness of epoxy resin was increased by the addition of $TiO_2$ nanoparticle. But the size of $TiO_2$ nanoparticle did not strongly affected to the Vickers hardness of this material. The fracture surface of epoxy resin showed clear difference by the size of $TiO_2$ nanoparticlet.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 하계학술대회 논문집 Vol.9
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• pp.358-359
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• 2008

Solar cell based on dye-sensitized photoelectric conversion was studied by investigating the effects of the amount of $TiO_2$ nanofiber added to the $TiO_2$ paste, on surface morphology, good electric of the $TiO_2$ films and on the solar cell performance. Energy conversion efficiency was found to increased with $TiO_2$ nanofiber addition up to 7wt% in $TiO_2$ films. Maximum increase upto 15% in the efficiently was observed at 7 wt. % of $TiO_2$ nanofiber in $TiO_2$ electrode.

• 한국재료학회지
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• 제28권10호
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• pp.590-594
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• 2018

ZnO micro/nanocrystals are formed by a vapor transport method. Mixtures of ZnO and TiO powders are used as the source materials. The TiO powder acts as a reducing agent to reduce the ZnO to Zn and plays an important role in the formation of ZnO micro/nanocrystals. The vapor transport process is carried out in air at atmospheric pressure. When the weight ratios of TiO to ZnO in the source material are lower than 1:2, no ZnO micro/nanocrystals are formed. However, when the ratios of TiO to ZnO in the source material are greater than 1:1, the ZnO crystals with one-dimensional wire morphology are formed. In the room temperature cathodoluminescence spectra of all the products, a strong ultraviolet emission centered at 380 nm is observed. As the ratio of TiO to ZnO in the source material increases from 1:2 to 1:1, the intensity ratio of ultraviolet to visible emission increases, suggesting that the crystallinity of the ZnO crystals is improved. Only the ultraviolet emission is observed for the ZnO crystals prepared using the source material with a TiO/ZnO ratio of 2:1.

• 한국환경과학회지
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• 제15권7호
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• pp.677-688
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• 2006

Currently, the application of $TiO_2$ photocatalyst has been focused on purification and treatment of wastewater. However, the use of conventional $TiO_2$ slurry photocatalyst results in disadvantage of stirring during the reaction and of separation after the reaction. And the usage of artificial UV lamp has made the cost of photocatalyst treatment system high. Consequently, we studied that solar light/$TiO_2$ film system was designed and developed in order to examine disinfection characteristics of sewage wastewater treatment. The optimum conditions for disinfection such as solar light intensity, characteristic of sewage wastewater, amounts of $TiO_2$ and comparison of solar ligth/$TiO_2$ systems with UV light/$TiO_2$ system was examined. The results are as follows: (1) photocatalytic disinfection process with solar light in the presence of $TiO_2$ film more effectively killed total coliform (TC) than solar light or $TiO_2$ film absorption only. (2) The survival ratio of TC and residual ratio of organic material (BOD, CODcr) decreased with remain resistant material. (3) The survival ratio of TC and residual ratio of organic material (BOD, CODcr) decreased with the increase of amounts of $TiO_2$. (4) TC survival ratio decreased linearly with increasing UV light intensity. (5) The disinfection effect of solar light/$TiO_2$ slurry system decreased more than UV light/$TiO_2$ film systems. (6) The disinfection reaction followed first-order kinetics. We suggest that solar light instead of using artificial UV light was conducted to investigate the applicability of alternative energy source in the disinfection of TC and the degradation of organic material.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2006년도 영호남 합동 학술대회 및 춘계학술대회 논문집 센서 박막 기술교육
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• pp.117-120
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• 2006

$TiOCl_2$를 중화시키고 과산화수소와 반응시켜 Ti peroxo 전구체를 수열합성법을 이용하여 autoclave 반응기 내에서 가열하여 $TiO_2$ 졸을 제조하였다. Autoclave 반응기 내에 압력을 가하면 브룩카이트상 $TiO_2$졸이 형성됨을 확인하였고, 중화과정에서 NaCl을 첨가하여 Ti 수산화물 격자 내에 Na 이온을 포획되어 브룩카이트상이 나타남을 알 수 있었다. Na 이온의 첨가량에 따라 브룩카이트 결정상 함량이 달라져 광촉매 활성도 달라짐을 브룩카이트상 $TiO_2$가 코팅된 박막의 기상벤젠 광분해 실험을 통해 확인하였고 미세구조, 결정성, 광흡수도률 측정하여 특성평가를 실시하였다.

• 한국재료학회지
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• 제17권3호
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• pp.125-131
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• 2007

[ $TiO_{2}-solution$ ] was aaded in $SiO_{2}-solution$ by various composition. $SiO_{2}-TiO_{2}$ thin films were obtained by the dip-coating method on the $SiO_{2}$ glass substrates, and then heat-treated at various temperature. Nano-size $TiO_{2}$ particles dispersed $SiO_{2}-TiO_{2}$ films showed absorption peak by quantum size effect at short wavelength region $350{\sim}400nm$, which made them good candidates for non-linear optical materials and photo-catalytic materials. The thickness of $SiO_{2}-TiO_{2}$ films were $300{\sim}430nm$. The contact angle of $SiO_{2}-TiO_{2}$ films for water was $5.3{\sim}47.9^{\circ}$, and therefore it is clear that $SiO_{2}-TiO_{2}$ films have super hydrophilic properties and the self-cleaning effects.

• 센서학회지
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• 제18권3호
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• pp.217-221
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• 2009

Different methods of material engineering, used for improvement of solid state gas sensors parameters are reviewed in this report. The wide possibilities of material engineering in optimization of gas sensing properties were demonstrated on the example of $SnO_2,\;TiO_2\;and\;In_2O_3$-based sensors.

• 한국결정성장학회지
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• 제20권5호
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• pp.221-226
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• 2010

메칠멜캅탄($CH_3SH$) 가스를 검출하는 수정진동자(QCM) 가스센서를 QCM의 전극에 $TiO_2$ 나노입자와 전해질 폴리머를 증착하여 제조하였다. LBL-SA법에 의해 제조된 $TiO_2$/PSS 박막은 높은 비표면적을 나타내었고, 가스센서의 감도를 증가시켰다. 1.0 ppm의 농도를 갖는 메칠멜캅탄에 노출된 TEA 혹은 $TiO_2$/PSS 막이 증착된 QCM의 주파수 변이는 각각 약 9 Hz, 2 Hz 였다. ($TiO_2$/PSS) 박막의 증착수가 늘어남에 따라 제조된 박막의 비표면적이 증가하게 되어 QCM 센서의 주파수 변이도 점차적으로 증가하였다. 추가적으로 메칠멜캅탄 가스의 농도가 0.5 ppm에서 2.0 ppm으로 높아짐에 따라 QCM 센서의 주파수 변화도 증가되었다. 본 연구에서는, ($TiO_2$/PSS) 박막이 증착된 QCM 센서의 표면구조의 변화와 센서 특성을 측정하였다.