• Journal of Korean Society of Environmental Engineers
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• v.30 no.3
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• pp.293-301
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• 2008

A study on the operational variables of the UV-TiO$_2$ based photocatalytic air cleaning system was tried. In this study, to examine effects as various air cleaning system conditions, a duct-type reactor was made, and TiO$_2$ was immobilized on a stainless mesh. Benzene was chosen as a target compound. Removal experiments for benzene were done under different initial benzene concentration, air velocity, TiO$_2$ loading, area coated TiO$_2$ as the same TiO$_2$ loading, and UV light intensity conditions. During the experiments, relative humidity was 55%, and reactor temperature was 45$^{\circ}C$. As a result, the photocatalytic degradation of benzene decreased as the inlet concentration increased. But the photocatalytic degradation increased as the concentration boundary layer thickness, amount of TiO$_2$, area coated TiO$_2$ as the same amount of TiO$_2$, and UV light intensity increased. Based on results of current study, they can be applied to the design of air cleaning system over low level VOCs in the indoor air.

• Applied Chemistry for Engineering
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• v.23 no.2
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• pp.148-152
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• 2012

Anatase and anatase/rutile $TiO_2$ samples were prepared at $HNO_3$/TTIP molar ratio of 0.1, 0.5, 1.0, and 1.5 to study the effects of the physical properties of $TiO_2$ on photocatalytic decomposition of methylene blue. The physical properties of the samples were measured with XRD, SEM, TEM, BET, FT-IR, and UV-vis spectroscopy. Anatase phase was observed at $HNO_3$/TTIP of 0.1 and anatase/rutile phases were observed at $HNO_3$/TTIP of 0.5~1.5. Rutile crystal phase, mesopore size between $TiO_2$ nanoparticles, and surface OH group on $TiO_2$ sample were gradually increased with increasing the molar ratio of $HNO_3$/TTIP and the residual methylene blue concentration before UV irradiation decreased from 78.0 to 53.3%. After UV irradiation, the residual methylene blue concentrations of the samples prepared at $HNO_3$/TTIP of 0.1, 0.5, 1.0, and 1.5 were 20, 14, 11, and 23%, respectively, and the sample prepared at $HNO_3$/TTIP of 1.0 showed the best photocatalytic ability.

• Journal of the Korean Ceramic Society
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• v.39 no.8
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• pp.750-757
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• 2002

Self-patterning of thin films using photosensitive sol solution has advantages such as simple manufacturing process compared to photoresist/dry etching process. In this study, ferroelectric $Sr_{0.9}Bi_{2.1}Ta_2O_9$ thin films have been prepared by spin coating method using photosensitive sol solution. Strontium ethoxide, tertramethylheptanedionato bismuth and tantalum ethoxide were used as starting materials. As UV exposure time to the SBT thin film increased, the UV absorption peak intensity of metal ${\beta}$-diketonate decreased due to reduced solubility by M-O-M bond formation. Solubility difference by UV irradiation on SBT thin film allows to obtain a fine patterning of thin film. Also, The ferroelectric properties of the UV irradiated SBT thin films were superior to those of the no-UV irradiated films.

• Journal of Environmental Science International
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• v.26 no.3
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• pp.303-309
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• 2017

Aeration with low energy micro-bubble generation and $UV/H_2O_2$ processes was introduced to verify the possibility of oxidation treatment for acid mine drainage. During 10 hours of aeration with micro-bubbles, Fe and As concentrations were decreased to 18.1 and 61.8%, respectively, while Cu, Cd, Al were kept at influent concentrations. Other heavy metals such as Mn, Cr, Pb, Zn, and Ni concentrations fluctuated due to the repetition of oxidation and release. Twenty days of aeration indicated the oxidation possibility for Cu, Cd, and Al. With the employment of $UV/H_2O_2$ processes, more than 77% of Cu and Fe removed, whereas slightly more than 30% of Cd and Al removed.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.22 no.3
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• pp.230-234
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• 2009

Hydrogen and Oxygen plasma treatments have been done on sonochemical grow ZnO nanorods by varying treatment temperature and time, The changes(position and intensity) in ultraviolet(UV) peaks and green peaks of photoluminescence(PL) spectroscopy have been measured, Experimental results showed; i) in the case of hydrogen plasma treatment, the blue shift of UV peak and the increase of PL intensity of the UV peak were observed as the increase of the process time and temperature, ii) in the case of oxygen plasma treatment, the red shift of green peak was observed and the ratio of $I_{Green}/I_{UV}$ was also increased, as the increase of the process time and the temperature.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.394-394
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• 2012

We fabricated organic-inorganic superlattice films using molecular layer deposition (MLD) and atomic layer deposition (ALD). The MLD is a gas phase process in the vacuum like to atomic layer deposition (ALD) and also relies on a self-terminating surface reaction of organic precursor which results in the formation of a monolayer in each sequence. In the MLD process, 'Alucone' is very famous organic thin film fabricated using MLD. Alucone layers were grown by repeated sequential surface reactions of trimethylaluminum and ethylene glycol at substrate temperature of $80^{\circ}C$. In addition, we developed UV-assisted $Al_2O_3$ with gas diffusion barrier property better than typical $Al_2O_3$. The UV light was very effective to obtain defect-free, high quality $Al_2O_3$ thin film which is determined by water vapor transmission rate (WVTR). Ellipsometry analysis showed a self-limiting surface reaction process and linear growth of each organic, inorganic film. Composition of the organic films was confirmed by infrared (IR) spectroscopy. Ultra-violet (UV) spectroscopy was employed to measure transparency of the organic-inorganic superlattice films. WVTR is calculated by Ca test. Organic-inorganic superlattice films using UV-assisted $Al_2O_3$ and alucone have possible use in gas diffusion barrier for OLED.

• Journal of the Korean Ceramic Society
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• v.40 no.3
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• pp.279-285
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• 2003

Ferroelectric S $r_{0.9}$B $i_{2.1}$T $a_{1.8}$N $b_{0.2}$ thin films with 200 nm thicknesses were deposited on Pt/Ti $O_2$/ $SiO_2$/Si Substrates by a sol-gel method. In these experiments, Sr(O $C_2$ $H_{5}$)$_2$, Bi(TMHD)$_3$, Ta(O $C_2$ $H_{5}$)$_{5}$ and Nb(O $C_2$ $H_{5}$)$_{5}$ were used as precursors, which were dissolved in 2-methoxyethanol. After UV-irradiation and RTA processes, the remanent polarization value (2 $P_{r}$) of SBTN thin films with annealed at $650^{\circ}C$ was 8.49 and 11.94 $\mu$C/$\textrm{cm}^2$ at 3 V and 5 V, respectively.

• Journal of Korean Ophthalmic Optics Society
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• v.9 no.1
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• pp.69-73
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• 2004

TSEE and TSL phenomena have been measured for ${\alpha}-Al_2O_3$ single crystals by the use of the $2{\pi}$ proportional counter. The ${\alpha}-Al_2O_3$ crystals irradiated to X-ray and UV for the temperature range from room temperature to about 500k degree. Three peaks of TSEE and three peaks of TSL were observed after X-ray irradiation. Also, two peaks of TSEE and three TSL peaks were observed after UV irradiation. TSEE and TSL glow curves of ${\alpha}-Al_2O_3$ single crystals showed very similar to the peaks position regardless of excitation sorts. Form this work, we knew that the $2{\pi}$ proportional counter is useful to not only the energy spectrum analysis device of ${\alpha}$-particle, but also the measurement instrument of TSEE and TSL.

• Journal of Food Hygiene and Safety
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• v.19 no.2
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• pp.97-103
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• 2004

The present study was performed to investigate photodegradation rate constants and degradation products of piperophos by the USEPA method. The pesticide was very stable in 16 days exposure of sunlight from October 3 to 22, 2003 and humic acid had no sensitizing effect on the photolysis of each pesticide in sunlight. In the UV irradiation test, piperophos was rapidly degraded as increasing UV intensity. In case of UV irradiation with TiO$_2$ and with TiO$_2$ powder amount, degradation of piperophos was slower than UV irradiation. In order to identify photolysis product, the extracts of degradation product was analyzed by GC/MS. The mass spectrum of photolysis product of piperophos was at m/z 166. It was suggested that the photolysis products of piperophos was O, O-dipropyl phosphorodithioate.

• The Korean Fashion and Textile Research Journal
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• v.5 no.4
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• pp.395-398
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• 2003

In this study, we measured the antibacterial activities, deodorization, UV cut ability, whiteness and SEM, according to the size($5{\mu}m$, $15{\mu}m$) of $TiO_2$, concentration(3%, 5%, 10%) and dipping temperature($50^{\circ}C$, $70^{\circ}C$) with using anatase type of $TiO_2$ photocatalyst. Photocatalyst is the substance which carries out functions, such as decomposition, removal, deodorization, antibacterial, etc. of a contaminant, in a place with light based on an oxidation-reduction reaction. The results of this study were as follow. Antibacterial activities are increased with increasing of the $TiO_2$'s concentration, and $TiO_2$ has high antibacterial activities for Staphylococcus aureus but it has low antibacterial activities for Klebsiella pneumoniae. The deodorization and UV cut ability is very good, therefore be able to get good effects with using only 3% of $TiO_2$. Every effects are increased by using small size of $TiO_2$ and high dipping temperature.