• Proceedings of the Korean Fiber Society Conference
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• 2003.04a
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• pp.372-373
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• 2003

전기방사는 고분자 용액에 전기장을 이용하여 나노섬유를 제조하는 유용한 방법이다. 전기방사에 의한 섬유 제조에 영향을 주는 공정인자들로는 고분자의 성질과 분자량 그리고 용액의 농도와 점도, 용매, 전기장의 세기, 콜렉터와의 거리에 의존한다[1-3]. TiO$_2$-SiO$_2$ 나노구조는 광학성, 열안정설, 내화학성 그리고 낮은열팽창성이 우수하여 반투명 코팅재, 광학센서, 광학유리, 보강재, 촉매재 등 광범위하게 응용될 수 있다. (중략)

• Journal of the Korean Ceramic Society
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• v.30 no.9
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• pp.775-783
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• 1993

TiO2-SiO2 system anti-reflective(AR) film was prepared to decrease reflectance on the glass surface. The experiments were carried out as fellow, 1) preparation & hydrolysis of TiO2-SiO2 system sols. 2) glass dipping, and 3) drying & heat treatment. We investigated the refractive index and thickness of film with viscosity, zeta-potential of sol, sol concentration, withdrawal speed, drying and heat treatment condition. As a result, we prepared good qualitative Quarter-Half-Quarter type anti-reflective film that had minimum, 0.02% and average reflectance, 0.087% in the visible region.

• Journal of Korean Ophthalmic Optics Society
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• v.3 no.1
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• pp.237-242
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• 1998

A transparent and colorless $80SiO_2-20TiO_2$(mol%) thin films on soda-lime-silica slide glass and sapphire substrate were obtained by spin-coating technique using tetraethyl orthosilicate and titanium trichloride as starting materials. The prepared film annealed at $750^{\circ}C$ showed a high transmittance and a low reflectance. For the $SiO_2-TiO_2$ films on slide glasses, a strong interaction between the sodium ion and oxygens is properbly the origin of the good stability to the high temperature and the high humidity.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.35D no.3
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• pp.39-45
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• 1998

SrBi$_{2}$Ta$_{2}$O$_{9}$ (SBT) ferroelectric thin films for nonvolatile memory were prepared on Pt/Ti/SiO$_{2}$/Si and RuO$_{2}$/SiO$_{2}$/Si substrates by RF magnetron sputtering. The dependences of crystalline and electrical properties on the lower electrode type(Pt and RuO$_{2}$) and the annealing temperatures were investigated. SBT films regardless of their electrode types showed typeical Bi layered peroviskite crystal structures. The crystalline quality of as-deposited SBT films was improved by the rapid thermal annealing at 650.deg. C for 30 sec. The remanetn polarization of 2Pr (Pr+-Pr-) of the annealed SBT films deposited on Pt/Ti/SiO$_{2}$/Si substrates were about 11 .mu.C/cm$^{2}$ and 3 .mu.C/cm$^{2}$, respectively. The leakage currents at 3 V bias voltage were about 0.8 .mu.A/cm$^{2}$ for SBT/ Pt/Ti/SiO$_{2}$/Si and about 1 .mu.A/cm$^{2}$ for SBT/RuO$_{2}$/SiO$_{2}$/Si sample. SBT films annealed at 650 .deg. C showed no degradation in Pr values after 10$^{11}$ polarization switching cycles, indicating good fatigue properties. In addition, for SBT samples deposited on Pt/Ti/SiO$_{2}$/Si, Pr values increased to more than that of initial state, suggesting the increament of leakage current caused by repeated polarization.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.33 no.3
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• pp.186-193
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• 2009

In this article, the effect of silica addition on the phase transformation characteristics of $TiO_2$ nanoparticles synthesized by using an $O_2$-enriched coflow, hydrogen, diffusion flame was investigated. TTIP(titanium tetra-isopropoxide) and TEOS(tetraethyl-orthosilicate) were used as precursors for $TiO_2$ and $SiO_2$ nanoparticles, respectively. Based on the results from TEM and XRD analysis, it is believed that the silica addition on the flame synthesis of $TiO_2$ nanoparticles reduces the particle size distribution and raises the temperature of the phase transition from anatase to rutile. But the reduced sizes of the synthesized particles due to the silica addition made the sintering and phase transformation of particles more easily.

• Korean Journal of Materials Research
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• v.34 no.6
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• pp.275-282
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• 2024

In this work, we investigated the photo-degradation performance of MnO₂-SiC fiber-TiO₂ (MnO₂-SiC-TiO₂) ternary nanocomposite according to visible light excitation utilizing methylene blue (MB) and methyl orange (MO) as standard dyes. The photocatalytic physicochemical characteristics of this ternary nanocomposite were described by X-ray diffraction (XRD), scanning electron microscopy (SEM), tunneling electron microscopy (TEM), ultraviolet-visible (UV-vis), diffuse reflectance spectroscopy (DRS), electrochemical impedance spectroscopy (EIS), photocurrent and cyclic voltammogram (CV) test. Photolysis studies of the synthesized MnO₂-SiC-TiO₂ composite were conducted using standard dyes of MB and MO under UV light irradiation. The experiments revealed that the MnO₂-SiC-TiO₂ exhibits the greatest photocatalytic dye degradation performance of around 20 % with MB, and of around 10 % with MO, respectively, within 120 min. Furthermore, MnO₂-SiC-TiO₂ showed good stability against photocatalytic degradation. The photocatalytic efficiency of the nanocomposite was indicated by the adequate photocatalytic reaction process. These research results show the practical application potential of SiC fibers and the performance of a photocatalyst composite that combines these fibers with metal oxides.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.663-663
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• 2013

We prepared Cu oxides, and Ni and Pd-TiO2@SiO2 core-shellnanostructures, and tested their CO oxidation performances by temperature-programmed mass spectrometry. We found the starting temperatures of CO oxidation are around $200^{\circ}C$ and $300^{\circ}C$ for Ni and Pd-TiO2@SiO2 nanostructures, respectively. Cu oxides are cubes with 50~200 nm with, prepared with different concentrations of NaOH and ascorbic acid. For the core-shell structures, we prepared 100 nm SiO2 spheres, first coated the surface with TiO2 precursor, and then coated with Ni and Pd. Their characteristics are further examined by scanning electron microscopy, optical microscope, FT-IR, and UV-Vis absorption spectroscopy.

• Proceedings of the Optical Society of Korea Conference
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• 2001.02a
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• pp.266-267
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• 2001

TiO$_2$와 SiO$_2$는 일반적으로 가시광 영역에서부터 근적외선까지의 넓은 파장영역의 광학박막을 제작하기 위한 물질로서 사용되어져 오고 있다. 이 두 물질은 비교적 큰 굴절률 차이를 지니고 있어 이들을 이용한 다층박막 또는 혼합박막에 대한 연구가 이루어져왔다. TiO$_2$-SiO$_2$ 혼합박막을 제작하기 위해 e-beam evaporation, CVD, flame hydrolysis, sol-gel 등 다양한 방법이 연구되고 있다. 특히 sol-gel법은 혼합물질의 조성이 용이하고 최종 물질의 광학적 특성이 우수하다. (중략)

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.52 no.2
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• pp.80-84
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• 2003

The mechanical and electrical properties of the hot-pressed and pressureless annealed SiC-Ti $B_2$electroconductive ceramic composites were investigated as functions of the liquid additives of $Al_2$ $O_3$+ $Y_2$ $O_3$. The result of phase analysis for the SiC-Ti $B_2$ composites by XRD revealed $\alpha$-SiC(6H), Ti $B_2$, and YAG(A $l_{5}$ $Y_3$ $O_{12}$ ) crystal phase. The relative density of SiC-Ti $B_2$ composites was increased with increased $Al_2$ $O_3$+ $Y_2$ $O_3$ contents. The fracture toughness showed the highest value of 6.04 Mpa $m^{\frac{1}{2}}$ for composites added with l2wt% A1$_2$ $O_3$+ $Y_2$ $O_3$ additives at room temperature. The electrical resistivity showed the lowest value of 6.2$\times$10$^{-3}$ $\Omega$ㆍcm for composite added with l6wt% $Al_2$ $O_3$+ $Y_2$ $O_3$ additives at room temperature. The electrical resistivity of the SiC-Ti $B_2$ composites was all positive temperature cofficient resistance(PTCR) in the temperature ranges from $25^{\circ}C$ to $700^{\circ}C$.

• Proceedings of the Optical Society of Korea Conference
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• 2002.07a
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• pp.196-197
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• 2002

졸-겔법은 비정질이나 결정질의 산화물 박막을 제작하는 유용한 방법중 하나이다.(1) 또한 졸-겔법은 제작하고자 하는 특성의 시편을 비교적 쉽게 구현할 수 있다는 장점이 있다. TiO$_2$와 SiO$_2$ 박막은 비교적 큰 굴절률 차이를 갖고 있어 혼합비에 따라 넓고 완만한 굴절률 분포를 가진다.(2) 이것은 박막이 원하는 광학적 특성을 가지게 하여 광학이나 촉매 분야에 응용할 수 있는 가능성이 크다는 것을 의미한다. (중략)