• 한국진공학회지
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• 제16권6호
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• pp.446-452
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• 2007

R.F. magnetron-sputtering 방법에 의해 $(Pb_{1.1},La_{0.08})(Zr_{0.65}.Ti_{0.35})O_3$ 박막을 $Pt/Ti/SiO_2/Si$, $TiO_2(interlayer)/Pt/Ti/SiO_2/Si$ 기판에 증착하고, $TiO_2$ interlayer에 의한 PLZT 박막의 특성을 고찰 하였다. $TiO_2$ interlayer의 증착조건을 변화시켜가며 단일상의 anatase 상과 rutile 상을 증착하였고, 그 위에 증착시킨 PLZT 박막의결정성을 x-ray diffraction(XRD)을 통해 분석하였다. 또한 $TiO_2$ interlayer에 의한 $PLZT-TiO_2$, $TiO_2-Pt$ 박막의 계면상태를 고찰하기 위해 glow discharge spectrometer(GDS) 분석을 행하였고, PLZT의 강유전 특성을 고찰하기 위해 전기적 측정을 행하였다. $TiO_2$ anatase 단일 상에 증착한 PLZT의 경우 (110) 방향으로 우선 배향됨을 알 수 있었고, 12.6 ${\mu}C/cm^2$의 잔류분극 값을 나타내었다.

• 한국감성과학회:학술대회논문집
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• 한국감성과학회 2009년도 추계학술대회
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• pp.258-260
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• 2009

광촉매능을 갖는 $TiO_2$는 국내외적으로 많은 연구가 진행되고 있으며, 빛의 조사로 발생하는 다양한 물리 화학적 촉매특성이 환경정화뿐만 아니라 및 에너지 흡수차단 기능도 갖고 있어 최근 주목을 받고 있다. 본 연구에서는 친수성을 가지는 친환경 창호소재용 및 초친수성을 가지는 자동차의 사이드미러 개발을 위해 유리표면에 이종밴드갭을 갖는 복합구조 $TiO_2/Cr_2O_3/Cr$ 박막을 스퍼터링법으로 증착하여 중간층인 $Cr_2O_3$의 역할을 고찰하였다. Cr, 결정질 $Cr_2O_3$ 기판의 경우 Anatase상과 Rutile상이 공존하는 미세조직이 관찰 되었으며 비정질 $Cr_2O_3$ 기판의 경우는 균일한 결정질 anatase-$TiO_2$상이 나타났다.

• Bulletin of the Korean Chemical Society
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• 제29권1호
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• pp.159-164
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• 2008

Two kinds of CNT/TiO2 composite photocatalysts were synthesized with multi-walled carbon nanotubes (MWCNTs) and titanium(IV) n-butoxide (TNB) by a MCPBA oxidation method. Since MWCNTs had charge transfer and semiconducting, the CNT/TiO2 composite shows a good photo-degradation activity. The XRD patterns reveal that only anatase phase can be identified for MCT composite, but the HMCT composite synthesized with HCl treatment was observed the mixed phase of anatase and rutile. The EDX spectra were shown the presence as major elements of Ti with strong peaks. From the SEM results, the sample MCT and HMCT synthesized by the thermal decomposition with TNB show a homogenous sample with only individual MWCNTs covered with TiO2 without any jam-like aggregates between CNTs and TiO2. From the photocatalytic results, we could be suggested that the excellent activity of the CNT/TiO2 composites for organic dye and UV irradiation time could be attributed to combination effects between TiO2 and MWCNTs with plausible photodegradation mechanism.

• 한국세라믹학회지
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• 제39권6호
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• pp.550-557
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• 2002

광촉매용 TiO$_2$코팅 석탄회 복합체를 침전제적하법을 이용하여 합성한 후, $700^{\circ}C$에서 2시간 열처리하여 제조하였다. 석탄회 표면의 TiO$_2$ 입자 석출상태와 결정상은 반응용액의 pH, 침전제인NH$_4$HCO$_3$의 주입속도, 교반속도, 반응온도 및 TiC1$_4$ 의 첨가량에 영향을 받았다. NH$_4$HCO$_3$의 주입속도=1.0ml/min, 반응용액의 pH=6, 교반속도=1,000rpm 및 반응온도=8$0^{\circ}C$인 석탄회의 표면에는 약 10m의 TiO$_2$ 입자가 균일하게 석출되었으나,NH$_4$HCO$_3$의 주입속도=0.3 및 0.5ml/min, 반응용액의 pH=2 및 11 ,교반속도=300~500rpm 및 반응온도=5$0^{\circ}C$ 이하인 석탄회의 표면에는 불균일한 TiO$_2$ 입자의 석출이 관찰되었다. NH$_4$HCO$_3$의 주입속도와 반응온도가 증가하고 TiC1$_4$의 농도가 감소함에 따라 석탄회 표면에 석출된 anatase상의 결정성은 열처리온도에 따라 증가하였으나,800"C에서 rutile로 전이하였다 반응온도와 NH$_4$HCO$_3$의 주입속도 및 Tic14의 농도가 증가함에 따라 rutile상이 생성되었다. $700^{\circ}C$에서 2시간 열처리하여 약 21m의 anatase상 TiO$_2$ 입자가 코팅된 석탄회 복합체는 1.25g/㎤의 밀도, 82.8%의 강도 및 69.5Lab의 백색도를 나타내었으며, 광촉매로 응용이 가능하였다.능하였다.

• 연구논문집
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• 통권33호
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• pp.123-135
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• 2003

Using the residence time calculated by computer simulation for temperature and gas velocity distribution in CVC reactor, the kinetics on the formation of $TiO_2$ nano powder was analyzed for coagulation process, After abrupt increase of particle size at initial growth stage (< 0.2 $\mus$ ), the particle grew in proportion of cubic root to time. The numerically calculated particle sizes well agreed with the experimental results. However, the coarse rutile $TiO_2$ powders having the particle size of over 40 nm were formed on the surface of quratz rod in the reactor. it is thought that the fine anatase particles condensed on quratz rod were sintered in a heated CVC reactor to grow and transform to coarse rutile phase, and the critical size for phase transformation anstase-to-rutile was around 25 nm tn this study.

• Carbon letters
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• 제7권4호
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• pp.259-265
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• 2006

Carbon-coated $TiO_2$ was prepared by $CCl_4$ solvent mixing method with the different heat treated temperatures (HTTs). Since the carbon layers derived from pitch on the $TiO_2$ particles were porous, the carbon-coated $TiO_2$ sample series showed a good adsorptivity. The values of BET surface areas measured were shown independently on the HTTs. The surface states by SEM present to the characterization of porous texture on the carbon-coated $TiO_2$ sample and carbon distributions on the surfaces. From XRD data, PT700 and PT750 were shown the X-ray diffraction patterns of the anatase $TiO_2$, but PT800 and PT850 were kept anatase-type structure even after heating at $800^{\circ}C$, though small amount of the rutile-type structure appears. The results of EDX microanalyses were observed for each sample show the spectra corresponding to almost all samples similar to C, O and Ti elements with an increase of HTTs. Finally, the excellent photoactivity of carbon-coated $TiO_2$ (especially, PT700 and PT750) could be attributed to the homogeneous coated carbon on the external surface and the structural anatase phase.

• 한국전기전자재료학회논문지
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• 제26권8호
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• pp.608-613
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• 2013

In this paper, the low-temperature sintering of $TiO_2$ is approached to solve the problem of high temperature sintering which decreases the interconnection between particles or between substrate and particle. $TiO_2$ paste is prepared with Titanium (IV) isopropoxide as the precursor material and calcinate at different conditions (low temperature). In the results, since the changing of temperature and time of sintering, crystalline phase do not change and the intensities of anatase, rutile phase are higher. At $110^{\circ}C$, 7 h sintering condition, crystalline size of anatase and rutile phase are the smallest which are 13.07 and 17.47 nm, respectively. In addition, the highest zeta potential is about 32.77 mV and the repulsive force increases thus leading to the best of the dispersion characteristics between $TiO_2$ particles. Futhermore, DSSCs at that condition exhibits the highest efficiency with the values of $V_{oc}$, $J_{sc}$, FF and ${\eta}$ are 0.69 V, $8.60mA\;cm^{-2}$, 67.93% and 4.06%, respectively.

• 한국세라믹학회지
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• 제55권6호
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• pp.618-624
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• 2018

We developed a mass production method that simultaneously controls the phase transformation and crystal size of $TiO_2$ coatings on multiwalled carbon nanotubes (MWCNTs). Initially, MWCNTs were successfully coated with amorphous 15-20-nm-thick $TiO_2$ by an in-situ sol-gel method. As the calcination temperature increased in both air and argon atmospheres, the amorphous $TiO_2$ was gradually transformed into the fully anatase phase at approximately $600^{\circ}C$, a mixture of the anatase and rutile phases at approximately $700^{\circ}C$, and the fully rutile phase above approximately $800^{\circ}C$. The crystal size increased with increasing calcination temperature. Moreover, above $600^{\circ}C$, the size of crystals formed in air was approximately twice that of crystals formed in argon. The reason is thought to be that MWCNTs, which continuously supported the stresses associated with the reconstructive phase transformation, disappeared owing to complete oxidation in air at these high temperatures.

• 한국세라믹학회지
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• 제45권1호
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• pp.43-47
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• 2008

The photocatalyst of $TiO_2$ coated on a fly ash composites (TCF) was prepared from precipitant dropping method to remove the acetaldehyde by photocatalytic reaction. The TCF were characterized by crystal aize, crystal structure and specific surface area. The photodegradation of acetaldehyde has been investigated using a UV-illuminated fixed photocatalytic reactor with TCF catalyst and P-25 catalyst in gas phase. The effect of photodegradation reaction conditions, such as initial concentration of acetaldehyde, concentration of oxidant in mixed gas and the light intensity on the photodegradation of acetaldehyde were investigated. P-25 catalyst showed the highest photodegradation of acetaldehyde and anatase $TiO_2$ coated TCF showed higher decomposition rate than rutile coated TCF. The photodegradation rate of acetaldehyde increased with the decrease of flow rate, initial concentration of acetaldehyde ($C_i$) and water vapor, however, it was increased with the increas of UV light intensity. The optimum conditions were weight of TCF=10 g, flow rate=50 ml/min $C_i$=100 ppm, concentration of oxygen=20%, concentration of water vapor=100 ppm.

• 한국세라믹학회지
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• 제37권4호
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• pp.308-313
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• 2000

Hydrous titanium oxide particles with anatase phase were prepared from 0.05 mol TiCl4 solution using NH4HCO3 as precipitant by the droopping precipitant method. The sequential change of pH is completed by a sudden and steep increase in a pH value of the range of 6~7 to which the concentration of adsorbed OH- and H+ ions on TiO2 surface is equal. Rutile phase started precipitating with anatase phase as an increase of reaction temperature above 6$0^{\circ}C$ in aqueous 0.05mol TiCl4 solution and its specific surface area was found to decrease from 452 $m^2$/g($25^{\circ}C$) to 164$m^2$/g(8$0^{\circ}C$). Specific surface area decreased rapidly when anatase powders precipitated at 4$0^{\circ}C$ were heat-treated at temperature higher 40$0^{\circ}C$. FT-IR result confirmed that it was due to the decrease of OH species within hydrous titanium oxides. The loss of ethanol after illumination of the powder heated at $600^{\circ}C$ and $700^{\circ}C$ for 4 h was 66 and 68.8%, respectively.