• Korean Journal of Mineralogy and Petrology
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• v.33 no.3
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• pp.195-214
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• 2020

The Samgwang Au-Ag deposit has been one of the largest deposits in Korea. The deposit consists of eight lens-shaped quartz veins which filled fractures along fault zones in Precambrian metasedimentary rock, which feature suggest that it is an orogenic-type deposit. The Ti-bearing minerals occur in wallrock (titanite, ilmenite and rutile) and laminated quartz vein (rutile). They occur minerals including biotite, muscovite, chlorite, white mica, monazite, zircon, apatite in wallrock and white mica, chlorite, arsenopyrite in laminated quartz vein. Chemical composition of titanite has maximum vaules of 3.94 wt.% (Al₂O₃), 0.49 wt.% (FeO), 0.52 wt.% (Nb₂O₅), 0.46 wt.% (Y₂O₃) and 0.43 wt.% (V₂O₅). Titanite with 0.06~0.14 (Fe/Al ratio) and 0.06~0.15 (X_Al (=Al/Al+Fe³⁺+Ti)) corresponds with metamorphic origin and low-Al variety. Chemical composition of ilmenite has maximum values of 0.07 wt.% (ZrO₂), 0.12 wt.% (HfO₂), 0.26 wt.% (Nb₂O₅), 0.04 wt.% (Sb₂O₅), 0.13 wt.% (Ta₂O₅), 2.62 wt.% (As₂O₅), 0.29 wt.% (V₂O₅), 0.12 wt.% (Al₂O₃) and 1.59 wt.% (ZnO). Chemical composition of rutile in wallrock and laminated quartz vein has maximum values of 0.35 wt.%, 0.65 wt.% (HfO₂), 2.52 wt.%, 0.19 wt.% (WO₃), 1.28 wt.%, 1.71 wt.% (Nb₂O₃), 0.03 wt.%, 0.07 wt.% (Sb₂O₃), 0.28 wt.%, 0.21 wt.% (As₂O₅), 0.68 wt.%, 0.70 wt.% (V₂O₃), 0.48 wt.%, 0.59 wt.% (Cr₂O₃), 0.70 wt.%, 1.90 wt.% (Al₂O₃) and 4.76 wt.%, 3.17 wt.% (FeO), respectively. Rutile in laminated quartz vein is higher contents (HfO₂, Nb₂O₃, As₂O₅, Cr₂O₃, Al₂O₃ and FeO) and lower content (WO₃) than rutile in wallrock. The substitutions of rutile in wallrock and laminated quatz vein are as followed : rutile in wallrock [(Fe³⁺, Al³⁺, Cr³⁺) + Hf⁴⁺ + (W⁵⁺, As⁵⁺, Nb⁵⁺) ⟵⟶ 2Ti⁴⁺ + V⁴⁺, 2Fe²⁺ + (Al³⁺, Cr³⁺) + Hf⁴⁺ + (W⁵⁺, As⁵⁺, Nb⁵⁺) ⟵⟶ 2Ti⁴⁺ + 2V⁴⁺], rutile in laminated quartz vein [(Fe³⁺, Al³⁺) + As⁵⁺ ⟵⟶ Ti⁴⁺ + V⁴⁺, (Fe³⁺, Al³⁺) + As⁵⁺ ⟵⟶ Ti⁴⁺ + Hf⁴⁺, 4(Fe³⁺, Al³⁺) ⟵⟶ Ti⁴⁺ + (W⁵⁺, Nb⁵⁺) + Cr³⁺], respectively. Based on these data, titanite, ilmenite and rutile in wallrock were formed by resolution and reconcentration of cations (W⁵⁺, Nb⁵⁺, As⁵⁺, Hf⁴⁺, V⁴⁺, Cr³⁺, Al³⁺, Fe³⁺, Fe²⁺) in minerals of wallrock during regional metamorphism. And then rutile in laminated quartz vein was formed by reconcentration of cations (Nb⁵⁺, As⁵⁺, Hf⁴⁺, Cr³⁺, Al³⁺, Fe³⁺, Fe²⁺) in alteration minerals (white mica, chlorite) and Ti-bearing minerals reaction between hydrothermal fluid originated during ductile shear and Ti-bearing minerals (titanite, ilmenite and rutile) in wallrock.

• Investigative Magnetic Resonance Imaging
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• v.19 no.2
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• pp.76-87
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• 2015

Purpose: There is an ongoing search for a stent material that produces a reduced susceptibility artifact. This study evaluated the effect of manganese (Mn) content on the MRI susceptibility artifact of ferrous-manganese (Fe-Mn) alloys, and investigated the correlation between MRI findings and measurements of Fe-Mn microstructure on X-ray diffraction (XRD). Materials and Methods: Fe-Mn binary alloys were prepared with Mn contents varying from 10% to 35% by weight (i.e., 10%, 15%, 20%, 25%, 30%, and 35%; designated as Fe-10Mn, Fe-15Mn, Fe-20Mn, Fe-25Mn, Fe-30Mn, and Fe-35Mn, respectively), and their microstructure was evaluated using XRD. Three-dimensional spoiled gradient echo sequences of cylindrical specimens were obtained in parallel and perpendicular to the static magnetic field (B0). In addition, T1-weighted spin echo, T2-weighted fast spin echo, and $T2^*$weighted gradient echo images were obtained. The size of the low-intensity area on MRI was measured for each of the Fe-Mn binary alloys prepared. Results: Three phases of ${\alpha}^{\prime}$-martensite, ${\gamma}$-austenite, and ${\varepsilon}$-martensite were seen on XRD, and their composition changed from ${\alpha}^{\prime}$-martensite to ${\gamma}$-austenite and/or ${\varepsilon}$-martensite, with increasing Mn content. The Fe-10Mn and Fe-15Mn specimens comprised ${\alpha}^{\prime}$-martensite, the Fe-20Mn and Fe-25Mn specimens comprised ${\gamma}+{\varepsilon}$ phases, and the Fe-30Mn and Fe-35Mn specimens exhibited a single ${\gamma}$ phase. The size of the low-intensity areas of Fe-Mn on MRI decreased relative to its microstructure on XRD with increasing Mn content. Conclusion: Based on these findings, proper conditioning of the Mn content in Fe-Mn alloys will improve its visibility on MR angiography, and a Mn content of more than 25% is recommended to reduce the magnetic susceptibility artifacts on MRI. A reduced artifact of Fe-Mn alloys on MRI is closely related to the paramagnetic constitution of ${\gamma}$-austenite and/or ${\varepsilon}$-martensite.

• Journal of the Korean institute of surface engineering
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• v.35 no.2
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• pp.107-112
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• 2002

We have studied diffusion behavior of NiFe/Ag bilayer deposited by on silicon Ion Beam Sputtering methods. The diffusion behavior of NiFe and Ag in NiFe/Ag thin film is analyzed by Medium Energy Ion Scattering Spectroscopy. For samples without Ta underlayer, silicides such as Ni-Si or Fe-Si were formed at Si substrate and NiFe interface. In contrast, Ag predominantly diffused into the NiFe layer probably through their grain boundaries for Ta underlayered samples.

• Journal of The Korean Society of Grassland and Forage Science
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• v.24 no.4
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• pp.281-292
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• 2004

This pot experiment was conducted to investigate the effects of systematic variation appling of Fe, Mn, Cu, and Zn on forage performance of orchardgrass and white clover, The treatments of systematic variation were 0/100. 25/75, 50/50. 75/25, and $100/0\%$ in the Fe/Cu, Mn/Zn, and Fe+Cu/Mn+Zn trials, respectively. The treatments of Fe/Mn/Cu/Zn trial were $70\%$ in main-element and $10\%$ in other 3sub-elements. 1 . General differences had been showed in the relative contents, uptake amounts, and mutual ratios of Fe, Mn, Cu, and Zn between orchardgrass and white clover. The effects of Fe application on the all traits were generally insignificant. The Mn and Cu applications, however, showed consistent differences in the all traits. At the high relative content of Mn in the forages influenced by the Mn application, the relative contents of Fe, Cu and Zn were greatly decreased without the significant differences in common content. 2. The increase of uptake amount of each micronutrient was not positively correspond to the yield increase. In some cases, the uptake amount of micronutrient was greatly increased without the significant increase of yield. At the Mn application, the Mn uptake amount was relatively much more increased than increase of the yield. The uptake amount of each element was significantly increased by the application with Mn and Cu. However, it was not in the case of Fe and Zn. 3. The mutual ratios of micronutrients were more influenced by the applications of Mn and Cu, especially Mn, than those by the applications of Fe and Zn. In the Fe/cu trial, the ratios of Fe/Cu showed 6.0~ 10.5 in orchardgrass and 10.2~ $16.4\%$ level of difference in white clover. In the Fe+Cu/Mn+Zn trial, the ratios of Mn/Cu, Mn/Zn, and Fe/Mn were greatly influenced by the treatments. It has been also found that the poor growth of white clover was caused by the unbalanced ratios of Fe/Mn, and it tended to be enhanced by the good applications and mutual ratios of other elements.

• Journal of the Mineralogical Society of Korea
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• v.27 no.4
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• pp.207-222
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• 2014

In order to recover the metallic copper powder from the mine-waste rock, heap bioleaching, Fe removal and electrowinning experiments were carried out. The results of heap leaching with the mine-waste rock sample containing 0.034% Cu showed that, the leaching rate of Cu were 61% and 62% in the bacteria leaching and sulfuric acid leaching solution, respectively. Sodium hydroxide (NaOH), hydrogen peroxide ($H_2O_2$) and calcium hydroxide ($Ca(OH)_2$) were applied to effectively remov Fe from the heap leaching solution, and then $H_2O_2$ was selected for the most effective removing Fe agent. In order to prepare the electrolytic solution, $H_2O_2$ were again treated in the heap leaching, and Fe removal rates were 99% and 60%, whereas Cu removal rates were 5% and 7% in the bacteria and sulfuric acid leaching solutions, respectively. After electrowinning was examined in these leaching solution, the recovery rates of Cu were obtained 98% in bacteria and obtained 76% in the sulfuric leaching solution. The dendritic form of metallic copper powder was recovered in both leaching solutions.

• Korean Journal of Animal Reproduction
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• v.23 no.3
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• pp.229-237
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• 1999

The influence of ascorbic acid (Asc) and ferrous sulfate (Fe$^{2＋}$) on capacitation, acrosome reaction and fertility in vitro was investigated in boar frozen-thawed spermatozoa with or without preincubation. The addition of 0-1.0 mM Fe$^{2＋}$ to sperm suspensions during preincubation increase acrosome reaction (P＜0.05) and oocyte penetration. These increase are also associated with addition of 0~0.5 mM Asc, but the penetration rates were higher in those without than with sperm preincubation. The addition of 0.1 mM Asc than 0.5 mM in medium with Fe$^{2＋}$ were significantly (P＜0.05) higher on acrosome reaction at 2 h after sperm preincubation. No significant differences, however, were observed in penetration rates among the concentrations of Asc. On the other hand, when preincubation medium containing the Asc was supplemented with 0.1mM Fe$^{2＋}$, the percentage of spermatozoa acrosome-reacted were significantly (P＜0.05) higher than in medium wothout Fe$^{2＋}$, on the contrary, the penetration rate was significantly (P＜0.05) low during in-vitro fertilization. These findings indicate some apparent effects of Fe$^{2＋}$ or Asc addition on acrosome reaction and the fertilizing potential by sperm preincubation.

• Journal of the Korean Magnetics Society
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• v.19 no.3
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• pp.106-112
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• 2009

$Ni_{1-x}Mg_xFe_2O_4$ ferrite system was studied by using X-ray diffraction and $M{\ddot{o}}ssbauer$ spectroscopy. The samples were prepared by ceramic sintering method with Mg content x. The X-ray diffraction patterns of samples show phase of cubic spinel structure. There are no remarkable changes of lattice constants in $Ni_{1-x}Mg_xFe_2O_4$ ferrite system. The $M{\ddot{o}}ssbauer$ spectra were consisted of two sets of six lines, respectively, corresponding to $Fe^{3+}$ at tetrahedral and octahedral sites. The magnetic hyperfine field of samples was decreased as increasing Mg contents x in both sites and it was shown Yafet-Kittel magnetic structure. $NiFe_2O_4$ was shown complete inverse spinel, but $NiFe_2O_4$ was shown partial inverse spinel which absorption area ratio (oct/tet) was 1.449 in $M{\ddot{o}}ssbauer$ spectrum.

• Journal of Environmental Health Sciences
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• v.20 no.1
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• pp.62-67
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• 1994

Introduction : Recently, water and environmental pollution becomes serious social problem and high technology makes this pollution accelerate. Hydrogen sulfide, the main subject of our research, is one of the most dangerous air pollutant like SO$_x$ and NO$_x$. The major contaminant in coal gasification is H$_2$S, which is very toxic, hazardous and extremely corrosive. Therefore, control of hydrogen sulfide to a safe level is essential. Although commercial desulfurization process called liquid scrubbing is effective for removal of H$_2$S, it has drawbacks, the loss of sensible heat of the gas and costly wastewater treatment. Many investigations are carried out about high-temperature removal ol H$_2$S in hot coal-derived gas using metal oxide or mixed metal qxide sorbents. It was reported that ZnO was very effective sorbent for H2S removal, but it has big flaw to vaporize elemental zinc above 600\ulcorner \ulcorner As alternative, metal oxides such as CaO, $Fe_2O_3$, TiO$_2$ and CuO were added to ZnO. Especially, different results are reported for $Fe_2O_3$ additive. Tamhankar et al. reported SiO$_2$ with 45 wt% $Fe_2O_3$ sorbent is favorable for removal of H$_2$S and regeneration.

• Journal of Powder Materials
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• v.19 no.2
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• pp.146-150
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• 2012

The effects of nano $Fe_xC$ addition to superconducting properties of $in$ $situ$ processed $MgB_2$ superconductors was examined. 0.1 wt.% and 1 wt.% nano $Fe_xC$ powders were mixed with boron and magnesium powders by ball milling. The powder mixtures were made into pellets by uniaxial pressing. The pellets were heat-treated at $700^{\circ}C-900^{\circ}C$ in argon atmosphere for $MgB_2$ formation. It was found by powder X-ray diffraction that the raw powders were completely converted into $MgB_2$ after the heat treatment. The superconducting transition temperature ($T_c$) and critical current density ($J_c$), estimated from susceptibility-temperature and $M-H$ curves, were decreased by nano $Fe_xC$ addition. The $T_c$ and $J_c$ decrease by nano $Fe_xC$ addition are attributed to the incorporation of iron and carbon with $MgB_2$ lattices (Fe substitution for Mg and C substitution for B) due to the high reactivity of the nano $Fe_xC$ powder.

• Journal of the Korean Society of Clothing and Textiles
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• v.22 no.8
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• pp.1132-1140
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• 1998

The adhesion and removal of $\alpha$-Fe2O3 particles on the from PET fabric in NPE solution with different ionic strength were discussed in terms of interaction of surface charge of particle and substrate. The adhesion of $\alpha$-Fe2O3 particles to PET fabric and its removal from PET fabric were carried out by using water bath shaker and Terg-O-Tometer under various solution conditions. The ζ potential of PET fiber and $\alpha$-Fe2O3 particles in the detergent solution were measured by steaming potential and microelectrophoresis methods, respectively. The adhesion and removal amount of $\alpha$-Fe2O3 particles on the from PET fabric increased with increasing time of adhesion and removal, and the rates of adhesion and removal were high at the initial stage of adhesion and removal, and then the rates decreased with passing time. The adhesion and removal amount of $\alpha$-Fe2O3 particles on and from PET fabric increased with increasing pH of solution regardless ionic strength. The tendencies and degree of adhesion and removal were very similar regardless interaction of surface charge of particle and fiber. Therefore, in the presence of a surfactant and electrolyte, the influence of interaction of surface charge of particle and substrate on the detergency of particulate soil was small.