• Smart Structures and Systems
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• v.25 no.3
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• pp.337-343
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• 2020

In this paper, we focused on the self-healing concrete using new nano-capsules. Three types of nano-capsules with respect to availability, high strength and temperature tolerance are used; type 1 is URF and polyethylene (PE) as shell and nano titanium oxide (TiO₂) as core, type 2 is URF and PE as shell and nano silica oxide (SiO₂) as core, type 3 is PE as shell and nano silica oxide (SiO₂) as core. The concrete samples mixed by nano-capsules with three percents of 0.5, 1 and 1.5. Based on experimental tests and the compressive strength of samples, the URF-PE-SiO₂ is selected for additional tests of compressive strength before and after recovery, ultrasonic test, ion chlorine and water penetration depths. After careful investigation, it is concluded that the optimum value of URF-PE-SiO₂ nano-capsules is 0.5% since leads to higher compressive strength, ultrasonic test, ion chlorine and water penetration depths.

• Journal of Korean Society of Environmental Engineers
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• v.33 no.3
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• pp.162-166
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• 2011

Phosphorous contaminated in the effluent from sewage treatment plants can cause the eutrophication in surface water bodies. In this study, a powder of titanium oxysulfate-sulfuric acid made of ion-exchange materials was immobilized in an alginate gel and this material was examined to evaluate its phosphorous removal efficiency. Equilibrium and kinetic studies were carried out to quantify the adsorption capacity and time dependent removal rate of phosphorous. Adsorption isotherms and kinetic parameters were obtained for the entrapped titanium beads with three different methods. Equilibrium data were analyzed using Langmuir adsorption isotherm model and found to be well fitted to the model. The maximum adsorption capacity for phosphorous by the titanium bead synthesized with the solution method was 92.26 mg/g. Kinetic data followed a pseudo-second-order kinetic model. Due to the low production cost and high adsorption capacity, the titanium bead synthesized by the solution method has a potential to be utilized for the cost-effective removal of phosphorous from wastewater.

• Journal of Biomedical Engineering Research
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• v.25 no.2
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• pp.157-163
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• 2004

Nitrogen ion implantation and ion plating techniques were applied for improvement of the wear resistance of metallic implant materials. In this work, the wear dissolution behaviour of a nitrogen ion implanted super stainless steel (S.S.S, 22Cr-20Ni-6Mo-0.25N) was compared with those of S.S.S, 316L SS and TiN coated 316L SS. The amounts of Cr and Ni ions worn-out from the specimens were Investigated using an electrothermal atomic absorption spectrometry. Furthermore, the Ti(Grade 2) disks were coated with TiN, ZrN and TiCN by use of low temperature arc vapor deposition and the wear resistance of the coating layers was compared with that of titanium. The chemical compositions of the nitrogen ion implanted and nitride coated layers were examined with a scanting auger electron spectroscopy. It wat observed that the metal ions released from the nitrogen ion implanted S.S.S surface were significantly reduced. From the results obtained, it was shown that the nitrogen ion implanted zone obtained with 100 KeV ion energy was easily removed within 200,000 revolutions from a wear dissolution testing under a similar load condition when applied to artificial hip joint. The remarkable improvement in wear resistance weir confirmed by the nitrides coated Ti materials and the wear properties differ greatly according to the chemical composition of the coating layers. for specimens with the same coating thickness of about 3$\mu\textrm{m}$, TiCN coated Ti showed the highest wear resistance. However, after removing the coating layers, the wear rates of all nitrides coated Ti reverted to their normal rates of below 10,000 revolutions from Ti-disk-on-disk wear testing under the same load condition. From the results obtained, it is suggested that the insufficient depth of the 100 Kel N$\^$＋/ ion implanted zone and of the nitrides coated layers of 3$\mu\textrm{m}$ are subject to restriction when used as frictional parts of load bearing implants.

• Bulletin of the Korean Chemical Society
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• v.31 no.4
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• pp.953-958
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• 2010

A laser ablation-molecular beam/reflectron time-of-flight mass spectrometric technique was used to investigate the ion-molecule reactions that proceed within $Ti^+(CH_3COCH_3)_n$ heterocluster ions. The reactions of $Ti^+$ with $CH_3COCH_3$ clusters were found to be dominated exclusively by an oxidation reaction, which produced $TiO^+(CH_3COCH_3)_n$ clusters. These ions were attributed to the insertion of a $Ti^+$ ion into the C=O bond of the acetone molecule within the heteroclusters, followed by $C_3H_6$ elimination. The mass spectra also indicated the formation of minor sequences of heterocluster ions with the formulas $Ti^+(C_3H_4O)(CH_3COCH_3)_n$ and $TiO^+(OH)(CH_3COCH_3)_n$, which could be attributed to C-H bond insertion followed by $H_2$ elimination and to the sequential OH abstraction by the $TiO^+$ ion, respectively. Density functional theory calculations were carried out to model the structures and binding energies of both the association complexes and the relevant reaction products. The reaction pathways and energetics of the $TiO^+\;+\;CH_2CHCH_3$ product channel are presented.

• Journal of Magnetics
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• v.11 no.1
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• pp.12-15
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• 2006

Magnetic and electronic properties of reduced rutile titanium dioxide $(TiO_{2-\delta})$ thin films doped by Mn have been investigated. The present sol-gel-grown semiconducting $TiO_{2-\delta}:Mn$ films exhibit a ferromagnetic behavior at room temperature for a limited range of Mn content. The Mn-doped films have p-type electrical conductivity with the carrier concentration near $10^{19}\;cm^{-3}$. The observed room-temperature ferromagnetism is believed to be intrinsic but not related to free carriers such as holes. Oxygen vacancies are likely to contribute to the room-temperature ferromagnetism-trapped carriers in oxygen vacancies can mediate a ferromagnetic coupling between neighboring $Mn^{+3}$ ions. The energy band-gap change due to the Mn doping measured by spectroscopic ellipsometry exhibits a red-shift compared to that of the undoped sample at low Mn content. It is explainable in terms of strong spin-exchange interactions between Mn ion and the carrier.

• Membrane Journal
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• v.17 no.3
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• pp.244-253
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• 2007

This research investigated the effect of a photocatalytic reaction on nanofiltration(NF) membrane fouling by natural organic matter(NOM). The photocatalytic degradation was very effective for destruction and transformation of NOM and was carried out by titanium dioxide($TiO_2$) and $TiO_2$-immobilized bead as a photocatalyst. In order to compare their phtocatalytic properties, the photocatalytic degradation of humic acid in the presence of calcium ion was used as a model reaction. After the photocatalytic degradation the membrane fouling was dramatically decreased.

• 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.

• Transactions on Electrical and Electronic Materials
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• v.12 no.3
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• pp.106-109
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• 2011

We investigated the etching characteristics of titanium nitride (TiN) thin film in $BCl_3$/Ar inductively coupled plasma. The etching parameters were the gas mixing ratio, radio frequency (RF) power, direct current (DC)-bias voltages and process pressures. The standard conditions were as follows: total flow rate = 20 sccm, RF power = 500 W, DC-bias voltage = -100 V, substrate temperature = $40^{\circ}C$, and process pressure = 15 mTorr. The maximum etch rate of TiN thin film and the selectivity of TiN to $Al_2O_3$ thin film were 54 nm/min and 0.79. The results of X-ray photoelectron spectroscopy showed no accumulation of etch byproducts from the etched surface of TiN thin film. The TiN film etch was dominated by the chemical etching with assistance by Ar sputtering in reactive ion etching mechanism, based on the experimental results.

• KIEE International Transactions on Electrophysics and Applications
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• v.5C no.3
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• pp.119-123
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• 2005

Lithium titanium oxide as anode material for energy storage prepared by novel synthesis method. Li$_{4}$Ti$_{5}$O$_{12}$ based spinel-framework structures are of great interest material for lithium-ion batteries. We describe here Li$_{4}$Ti$_{5}$O$_{12}$ a zero-strain insertion material was prepared by novel sol-gel method and by high energy ball milling (HEBM) of precursor to from nanocrystalline phases. According to the X-ray diffraction and scanning electron microscopy analysis, uniformly distributed Li$_{4}$ Ti$_{5}$O$_{12}$ particles with grain sizes of 100nm were synthesized. Lithium cells, consisting of Li$_{4}$ Ti$_{5}$O$_{12}$ anode and lithium cathode showed the 173 mAh/g in the range of 1.0 $\~$ 3.0 V. Furthermore, the crystalline structure of Li$_{4}$ Ti$_{5}$O$_{12}$ didn't transform during the lithium intercalation and deintercalation process.

• Transactions of the Korean hydrogen and new energy society
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• v.7 no.1
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• pp.29-37
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• 1996

Alkaline water electrolysis has been commercialized as the only large-scale method for a long time to produce hydrogen and the technology is superior to other methods such as photochemical, thermochemical water splitting, and thermal decomposition method in view of efficiency and related technical problem. However, such conventional electrolyzer do not have high electric efficiency and productivity to apply to large scale hydrogen production for energy or chemical feedstocks. Solid polymer electrolyte water electrolysis using a perfluorocation exchange membrane as an $H^+$ ion conductor is considered to be a promising method, because of capability for operating at high current densities and low cell voltages. So, this is a good technology for the storage of electricity generated by photovoltaic power plants, wind generators and other energy conversion systems. One of the most important R&D topics in electrolyser is how to minimize cell voltage and maximize current density in order to increase the productivity of the electrolyzer. A commercialized technology is the hot press method which the film type electrocatalyst is hot-pressed to soild polymer membrane in order to eliminate the contact resistance. Various technologies, electrocatalyst formed over Nafion membrane surface by means of nonelectrolytic plating process, porous sintered metal(titanium powder) or titanium mesh coated with electrocatalyst, have been studied for preparation of membrane-electrocatalyst composites. In this study some experiments have been conducted at a solid polymer electrolyte water electrolyzer, which consisted of single cell stack with an electrode area of $25cm^2$ in a unipolar arrangement using titanium mesh coated with electrocatalyst.