• Journal of the Korean institute of surface engineering
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• v.34 no.2
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• pp.135-141
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• 2001

Arc-melted Ti-6Al-4V, Ti-4Fe and Ti-(1,2) Si alloys were oxidized at 700, 800, 900 and $1000^{\circ}C$ in air. The oxidation resistance of Ti-4Fe was comparable to that of Ti-6Al-4V, while the oxidation resistance of Ti-(1,2) Si was superior to that of Ti-6Al-4V. Ti-2Si displayed the best oxidation resistance among the four alloys, but failed after oxidation at $1000^{\circ}C$ for 17h. The oxide scale formed on Ti-6Al-4V, Ti-4Fe and Ti-(1,2)Si consisted of ($TiO_2$ and a small amount of $Al_2$$O_3$), ($TiO_2$ and a small amount of dissolved iron), and ($TiO_2$ plus a small concentration of amorphous $SiO_2$), respectively. The oxide grains of the surface scale of the four alloys were generally fine and round.

• Applied Chemistry for Engineering
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• v.7 no.4
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• pp.645-652
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• 1996

Selective catalytic oxidation of $H_2S$ to elemental sulfur using $TiO_2/SiO_2$ catalysts was investigated in this study. The reaction test with pure $TiS_2$ and $Ti(SO_4)_2$ and cyclic temperature operation revealed that $TiO_2$ had a good resistance to sulfation and sulfidation, which are known as the main cause of catalytic deactivation in sulfur recovery process. With the increase of $TiO_2$ loading amount in $TiO_2/SiO_2$ catalysts, the conversion of $H_2S$ increased and the selectivity of elemental sulfur was very slightly decreased. As the ratio of $O_2/H_2S$ increased, the selectivity to elemental sulfur was drastically decreased. In the presence of 10 vol.% water vapor to a stoichiometric mixture of $H_2S$ and $O_2$($H_2S$= 5 vol.% O=2.5 vol.% ), both activity and selectivity of 10 wt.% $TiO_2/SiO_2$ catalyst are decreased, but it still showed more than 80% of sulfur yield.

• Journal of Sensor Science and Technology
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• v.23 no.3
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• pp.207-210
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• 2014

$TiO_2$ oxide semiconductor is being widely studied in various applications such as photocatalyst and photosensor. Pd/$TiO_2$ gas sensor is mainly used to detect $H_2$, CO and ethanol. This study focus on increasing hydrogen detection ability of Pd/$TiO_2$ in room temperature through Al-doping. Pd/$TiO_2$ was fabricated by the hydrothermal method. Contacting to Aluminum (Al) foil led to Al doping effect in Pd/$TiO_2$ by thermal diffusion and enhanced hydrogen sensing response. $TiO_2$ nanoparticles were sized at ~30 nm of diameter from scanning electron microscope (SEM) and maintained anatase crystal structure after Al doping from X-ray diffraction analysis. Presence of Al in $TiO_2$ was confirmed by X-ray photoelectron spectroscopy at 73 eV. SEM-energy dispersive spectroscopy measurement also confirmed 2 wt% Al in Pd/$TiO_2$ bulk. The gas sensing test was performed with $O_2$, $N_2$ and $H_2$ gas ambient. Pd/Al-doped $TiO_2$ did not response $O_2$ and $N_2$ gas in vacuum except $H_2$. Finally, the normalized resistance ratio ($R_{H2on}/R_{H2off}$) of Pd/Al-doped $TiO_2$ increases about 80% compared to Pd/$TiO_2$.

• Journal of the Microelectronics and Packaging Society
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• v.21 no.3
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• pp.31-35
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• 2014

$TiO_2$-nanoparticle-dispersed silicone was applied to a LED package and the light efficiency of the LED package was evaluated in this study. The addition of $TiO_2$ nanoparticles in silicone increased refractive index, which improved the light efficiency of the LED package. The $TiO_2$ nanoparticles were fabricated by hydrothermal synthesis and were dispsersed by a vinyl silane coating treatment. After the silane treatment, the $TiO_2$ nanoparticles dispersed with diameters of 10~40 nm but rod-shape $TiO_2$ nanoparticles with lengths of 100 nm were also observed. The refractive index increased with the $TiO_2$ concentration in silicone, while the transmittance decreased with the $TiO_2$ concentration. The light efficient of the LED package with $TiO_2$+silicone encapsulant was higher than that of the LED package with no $TiO_2$ in silicone encapsulant.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.23 no.6
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• pp.320-324
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• 2013

The effects of $CeO_2$ on catalytic activity of $CeO_2-TiO_2$ for the selective catalytic reduction (SCR) of $NO_x$ were investigated in terms of structural, morphological, and physico-chemical analyseis. $CeO_2-TiO_2$ catalysts were synthesized with three different additions, 10, 20, and 30 wt% of $CeO_2$, by the sol-gel method. The XRD peaks of all specimens were assigned to a $TiO_2$ phase (anatase) and the peaks became broader with the addition of $CeO_2$ because it was dispersed as an amorphous phase on the surface of $TiO_2$ particles. The specific surface area of $TiO_2$ increased with the addition of $CeO_2$ from $60.6306m^2/g$ to $116.2791m^2/g$ due to suppression of $TiO_2$ grain growth by $CeO_2$. The 30 wt% $CeO_2-TiO_2$ catalyst, having the strongest catalytic acid sites ($Br{\Phi}nsted$ and Lewis), showed the highest $NO_x$ conversion efficiency of 98 % at $300^{\circ}C$ among the specimens. It was considered that $CeO_2$ contributes to the improvement of the $NO_x$ conversion of $CeO_2-TiO_2$ catalyst by increasing specific surface area and catalytic acid sites.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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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.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.31 no.2A
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• pp.129-136
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• 2011

Recently studies on functional concrete with a photocatalytic material such as $TiO_2$ have actively been carried out in order to remove air pollutants. The absorbtion of $TiO_2$ from those studies is applied by it being directly mixed into concrete or by suspension coated on the surface. When it comes to the effectiveness, the former process is less than that of the latter compared with the $TiO_2$ use. As a result, the direct coating of $TiO_2$ on materials' surface is more used for effectiveness. The Surface spread of it needs to have a more than $400^{\circ}C$ heat treat done to stimulate the activation and adhesion of photocatalysis. Heat treat consequently leads hydration products in concrete to be dehydrated and shrunk and is the cause of cracking. The study produces $TiO_2$ used Sol-gel method which enables it to be coated with a low temperature treat, applies it to pearlite using Lightweight Aggregate Concrete fixed with a low temperature treat and evaluates the spread performance of it. In addition to this, the size of pearlite is divided into two types: One is 2.5 mm to 5.0 mm and the other is more than 5.0 mm for the benefit of finding out the removal characteristics of $CH_3CHO$ whether they are affected by pearlite size, mixing method and ratio with $TiO_2$ and elapsed time. The result of this experiment shows that although $TiO_2$ produced by Sol-gel method is treated with 120 temperature, it maintains a high spread rate on the XRF(X ray Florescence) quantitative analysis which ranks $TiO_2$ 38 percent, $SiO_2$ 29 percent and CaO 18 percent. In the size of perlite from 2.5 mm to 5.0 mm, the removal characteristic of $CH_3CHO$ from a low temperature heated Lightweight concrete appears 20 percent higher when $TiO_2$ with Sol-gel method is spreaded on the 7 percent of surface. In other words, the removal rate is 94 percent compared with the 72 percent where $TiO_2$ is mixed in 10 percent surface. In more than 5.0 mm sized perlite, the removal rate of $CH_3CHO$, when $TiO_2$ is mixed with 10 percent, is 69 percent, which is similar with that of the previous case. It suggests that the size of pearlite has little effects on the removal rate of $CH_3CHO$. In terms of Elapsed time, the removal characteristic seems apparent at the early stage, where the average removal rate for the first 10 hours takes up 84 percent compared with that of 20 hours.

• Korean Journal of Microbiology
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• v.37 no.2
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• pp.130-136
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• 2001

The killing effects of two types(one-phase reactor and two-phase reactor) of UV-TiO$_2$photocatalytic system on the microorganisms have been studied. The UV-lamp which emits maximum 39 watts at 254 nm was prepared in these system. Three types of $TiO_2$ coating method were adopted. One type is thin film coated form on the quartz tube in the reactor and another one is surface rough coated form on the glass bead. The other one is $TiO_2$-mixed alginate bead form. UV irradiation was carried out for 1 min. In case of one phase reactor, the bactericidal efficiencies of E. coli by $TiO_2$-coated quartz tube and $TiO_2$-coated glass bead were 63.2% and 89.9%, respectively. In the air-bubbling system, the bactericidal efficiency was 95%, however, the efficiency decreased to 90.6% in the non-bubbling system. In the $TiO_2$-mixed alginate bead system, bactericidal efficiency was 86%. When $H_2O$$_2$ was treated (10, 15, 20, and 25 mg/ι) to the $TiO_2$-coated glass bead reactor, bactericidal efficiency significantly increased according to the concentration of $H_2$$O_2$. Two phase reactor showed more elevated efficiency. E. coli was more sensitive to the reaction than S. cerevisiae.

• Proceedings of the Materials Research Society of Korea Conference
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• 2002.11a
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• pp.173-173
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• 2002

• Journal of the Korean Ceramic Society
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• v.38 no.9
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• pp.806-810
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• 2001

$La_{2/3}TiO_3$, $La_2Ti_2O_7$ are used in various parts by dielectric properties. The purpose of the present study is to understand the photoluminescence properties of $Al^{3+}\;and\;Pr^{3+}$ doped perovskite-type $La_{2/3}TiO_3$ and pyrochlore-type $La_2Ti_2O_7$ phosphor, which characterized by the red emission $(^1D_2{\rightarrow}^3H_4)\;of\;Pr^{3+}$ of $Pr^{3+}$ ion. The explanation for the energy transfer and the corresponding critical distance were proposed on the role of Al^3+ ions as energy transfer mediates in perovskite-type $La_{2/3}TiO_3$:Pr phosphor. In order to clarify the distinction of photoluminescence propoerties between the perovskite-type $La_{2/3}TiO_3$ and the pyrochlore $La_2Ti_2O_7$, the trap-involved process and the charge transfer band have been investigated.