• Bulletin of the Korean Chemical Society
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• v.25 no.6
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• pp.859-864
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• 2004

The solid solutions of the $Sr_{1-x}Ba_xFeO_{3-y)$ system (x = 0.0, 0.1, 0.2 and 0.3) having a perovskite structure were prepared in air at 1423 K and then heat-treated in air (A), $O_2(O)\;and\;N_2(N)$ to examine possibility of controlling the nonstoichiometry and applicability as an additive for electrical conducting inorganic adhesives (ECIA). In the samples heated in $N_2$ stream, there existed almost no $Fe^{4+}$ ions, and at constant temperature their electrical conductivities were considerably lower than those of the samples heat-treated in air or $O_2.\; Sr_{0.8}Ba_{0.2}Fe^{3+}_{0.49}Fe^{4+}_{0.51}O_{2.76}$ (SB2-A) whose $Fe^{3+}/Fe^{4+}$ ratio was nearly 1 (0.96) and whose conductivity values (1.04 $ohm^{-1}cm^{-1}$ at 283 K and 1.88 $ohm^{-1}cm^{-1}$ at 673 K) were higher than any other samples, was found to be the best additive for ECIA.

• Korean Journal of Materials Research
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• v.16 no.12
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• pp.739-742
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• 2006

The ${\gamma}-Fe_2O_3$ nano particles in the size range of $5{\sim}30$ nm were prepared by a chemical coprecipitation method. The nano particles were coated with 2nd surfactants for obtaining the water-based. The size effect of ${\gamma}-Fe_2O_3$ nano particles for the ultraviolet protection was investigated. The variation of the UV-Vis transmittance spectra as a function of wavelength for a ${\gamma}-Fe_2O_3$ nano particles were showed red-shifted increase with the particle size. The protective effects of UVA onset at near 469, 494, 591 nm for a particle size of 8.7, 9.1 and 12 nm. It is shown that the ${\gamma}-Fe_2O_3$ nano particles was good materials for protect of UV.

• Korean Journal of Metals and Materials
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• v.48 no.7
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• pp.674-682
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• 2010

Fe-fullerene/$TiO_2$ composite photocatalysts were prepared with titanium (IV) n-butoxide (TNB) by a sol-gel method. The samples were characterized by scanning electron microscopy (SEM), Transmission electron microscope (TEM), specific surface area (BET), X-ray diffraction analysis (XRD) and energy dispersive X-ray spectroscopy (EDX). The photocatalytic activities were evaluated by the photocatalytic degradation of methylene blue (MB) solution. XRD patterns of the composites showed that the Fe-fullerene/$TiO_2$ composite contained a typical single and clear anatase phase. The surface properties shown by SEM present a characterization of the texture on Fe-fullerene/$TiO_2$ composites and showed a homogenous composition in the particles for the titanium sources used. The EDX spectra for the elemental identification showed the presence of C and Ti with strong Fe peaks for the Fe-fullerene/$TiO_2$ composite. From the photocatalytic results, the excellent activity of the Fe-fullerene/$TiO_2$ composites for degradation of methylene blue under UV light irradiation could be attributed to both the effects between photocatalytic reaction of the supported $TiO_2$, decomposition of the organometallic reaction by the Fe compound and energy transfer effects such as electron and light of the fullerene.

• Korean Journal of Materials Research
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• v.16 no.2
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• pp.80-84
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• 2006

The removal efficiency of Cu and Fe contaminants on the silicon wafer surface was examined to investigate the effect of cleaning solutions on the behavior of metallic impurities. Silicon wafers were intentionally contaminated with Cu and Fe solutions by spin coating and cleaned in different types of cleaning solutions based on $NH_4OH/H_2O_2/H_2O\;(SC1),\;H_2O_2/HCl/H_2O$ (SC2), and/or HCl/$H_2O$ (m-SC2) mixtures. The concentration of metallic contaminants on the silicon wafer surface before and after cleaning was analyzed by vapor phase decomposition/inductively coupled plasma-mass spectrometry (VPD/ICP-MS). Cu ions were effectively removed both in alkali (SC1) and in acid (SC2) based solutions. When $H_2O_2$ was not added to SC2 solution like m-SC2, the removal efficiency of Cu impurities was decreased drastically. The efficiency of Cu ions in SC1 was not changed by increasing cleaning temperature. Fe ions were soluble only in acid solution like SC2 or m-SC2 solution. The removal efficiencies of Fe ions in acid solutions were enhanced by increasing cleaning temperature. It is found that the behavior of metallic contaminants as Cu and Fe from silicon surfaces in cleaning solutions could be explained in terms of Pourbaix diagram.

• Biomedical Science Letters
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• v.6 no.4
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• pp.261-268
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• 2000

Fibrinolytic enzyme (FE-2) was purified from the fruiting bodies of Tricholoma saponaceum using DEAE-Cellulose chromatography and Mono-S column chromatography, The enzyme has a molecular weight of 18.23 kDa and include Zn$^{2+}$ ion as found by ICP/MS. The N-terminal amino acid sequence of the enzyme was A-L-Y-V-G-X-S-P-X-Q-Q-S-L-L-V It has a pH optimum at pH 7.5, suggested that FE-2 was a neutral pretense. The activity of FE-2 was highly inhibited by EDTA and 1,10-phenanthroline, indicating that the enzyme is a metalloprotease. The activity of FE-2 was increased by $Mg^{2+}$, Zn$^{2+}$, Fe$^{2+}$, and Co$^{2+}$, but the enzyme activity was totally inhibited by Hg$^{2+}$. No inhibition was found with PMSF, E-64, pepstatin and 2-mercaptoethanol. The enzyme hydrolyzed both $A\alpha$ and B$\beta$ chains of human fibrinogen. The $\gamma$ chain was resistant to hydrolysis by FE-2.

• Journal of Industrial Technology
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• v.33 no.A
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• pp.89-92
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• 2013

The characteristics of floc formation of the iron(Fe) ions was studied for developing the process treating the acid mine drainage. The metal ions in aqueous solution oxidized with oxygen in air, which generated hydrogen ion and lowered the pH of the aqueous solution. The iron(Fe) ions were formed into flocs by the acid-base reaction with the added $Ca(OH)_2$ for the neutralizing the solution. There were several variables affecting the formation, size and color of floc; whether air was present or not, air feeding rate, oxidizing time, concentration of $Ca(OH)_2$, the acid-base reaction time of the $iron(Fe)-Ca(OH)_2$. For proper formation of the $iron(Fe)-Ca(OH)_2$ flocs and developing the floc treating system, the control variables mentioned above should be considered.

• Journal of the Korean Society of Safety
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• v.8 no.2
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• pp.3-9
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• 1993

For comparison, we used Ca and Mg as reducers to produce TiFe hydrogen stroage alloy from Fe and TiO$_2$by the Reduction-Diffusion process. The results obtained were as follow. \circled1 Ca was found to be effective both for reduction and diffusion processes. Moreover, Ca oxide was easily removed in an NH$_4$Cl solution after the reaction. \circled2 In the case of using Ca as a reducer, the Reduction-Diffusion process is considered to take place in the foiling three steps. First, TiO$_2$is reduced to Ti by Ca over 100$0^{\circ}C$. Second, the atomic Ti drifts in the Ca melt and meets Fe particles. Finally, the atomic Ti diffuses in to the Fe particles. \circled3 In the case of using Mg as a reducer, We found that the reduction reaction of TiO$_2$went well. But the reduced Ti scarcely diffused into Fe particles. This was probably because no Mg melt was formed due to the high vapor pressure of Mg.

• Journal of the Korean institute of surface engineering
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• v.33 no.4
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• pp.281-288
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• 2000

To understand the effect of Fe on the oxidation behavior of TiAl alloys, TiAl-(2, 4, 6at% )Fe were oxidized at 800 and 90$0^{\circ}C$ in air. The oxidation resistance of TiAl-Fe alloys increased with increasing an iron content. The scales formed consisted of an outer $TiO_2$ layer, an intermediate $A1_2$$O_3$ layer, and an inner mixed ($TiO_2$+$A1_2$$O_3$) layer, being similar to other common TiAl alloys. But, the scales formed on TiAl-Fe alloys were generally thin compared to those formed on pure TiAl, and contained dissolved iron. Below the oxide scale, an oxygen affected zone was formed. This beneficial effects of Fe on increasing the oxidation resistance and scale adherence of TiAl alloys were attributed to the refinement of oxide grains, increased scale adherence and the enhanced alumina-forming tendency.

• Journal of Korean Vacuum Science & Technology
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• v.6 no.1
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• pp.40-42
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• 2002

TiO$_2$/Fe$_2$O$_3$composite thin films were prepared on common glass substrates by sol-gel processing and dip-drawing method. The effect of Fe$_2$O$_3$content on the photocatalytic and hydrophilic properties of composite films was studied. The results indicate that the photocatalytic activities of composite TiO$_2$films are superior to that of pure TiO$_2$film, and the film containing 0.5% Fe$_2$O$_3$has the best photocatalytic activity. The hydrophilicity is difference with variant Fe$_2$O$_3$content, the films containing 0.05% ~0.1% Fe$_2$O$_3$have the best hydrophilicity and their contact angles are 0。.

• Korean Journal of Materials Research
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• v.17 no.10
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• pp.526-531
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• 2007

The sintering behavior and electrical property of $Ce_{0.8}Gd_{0.2}O_{1.9}$ ceramics were investigated with the iron oxide concentration ranging from 0 to 5 mol%. Both the sintered density and grain size were found to increase up to 2 mol% $Fe_2O_3$, and then to decrease with further additions. At a higher $Fe_2O_3$ content above 3 mol%, grain size decreased by a pinning effect induced by different shape grains. The electrical conductivity was also increased with increasing $Fe_2O_3$ content up to 2 mol%. Total conductivity of 2 mol% $Fe_2O_3-added$ specimen showed the maximum conductivity of $2{\times}10^{-2}{\Omega}{\cdot}cm^{-1}$ at $500^{\circ}C$. The addition of $Fe_2O_3$ was found to promote the sintering properties and electrical conductivities of $Gd_2O_3-dope\;CeO_2$.