• Journal of the Korean Vacuum Society
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• v.11 no.4
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• pp.240-248
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• 2002

$Fe_xTi_{l-x}O_2$ films (x=0.07 and 0.16) were grown by oxygen-plasma-assisted molecular beam epitaxy on rutile $TiO_2$(110). The same growth conditions were applied for both films in order to determine surface characteristics of grown films as a function of Fe composition. The films were characterized by several surface analysis techniques. The oxidation states of Ti and Fe in $Fe_xTi_{l-x}O_2$ films were found to be +4 and a mixture of +2 and +3, respectively. More $Fe^{3+}$ species exist in higher Fe doped film of $Fe_{0.16}Ti_{0.84}O_2$. The morphology of $Fe_{0.07}Ti_{0.93}O_2$ film shows tall rectangular and cylinderical islands growth on flat substrate-like surface. On the other hand, $Fe_{0.16}Ti_{0.84}O_2$ film consists of round shaped small islands showing somewhat rougher surface compared to the surface of $Fe_{0.16}Ti_{0.84}O_2$ film.

• Journal of the Korean Magnetics Society
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• v.1 no.1
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• pp.17-24
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• 1991

Laves phases of $NdFe_2$, $Nd{(Fe_{0.5})}_2$, $SmCo_2$ and $Sm{(Fe_{0.5}Co_{0.5})}_2$ stoichiometry were prepared using a rapid solidification technology. Low temperature magnetic properties show ferromagnetic behaviors for the $Nd{(Fe_{0.5}Co_{0.5})}_2$, $SmCo_2$ and $Sm{(Fe_{0.5}Co_{0.5})}_2$Nd(Feo,Coo,) Laves compounds while a sort of spin reorientation has been suggested for the supposed composition of $NdFe_2$ alloy. This rapidly solidified $NdFe_2$ alloy is believed to consist of metastable rhombohedral $NdFe_7$ phase plus fine particles of Nd-rich phase. Some evidence of phase transition from the mixture of unstable $NdFe_7$ compound plus Nd-rich to $Nd_2Fe_{17}$ plus Fe-Nd-O phase was obtained after annealing the $NdFe_2$, alloy. The pseudo-binary Laves compound, $Sm{(Fe_{0.5}Co_{0.5})}_2$ exhibits a high coercivityof 4 kOe at room temperature with Curie temperature of $400^{\circ}C$ while the $Nd{(Fe_{0.5}Co_{0.5})}_2$ compound shows a magnetic moment of $2.8\;{\mu}_B/f.u.$.

• Journal of the Mineralogical Society of Korea
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• v.20 no.4
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• pp.367-376
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• 2007

Aenigmatite, $Na_4(Fe^{2+},Ti,Fe^{3+}){_{12}}(Fe^{3+},Si){_{12}}O_{40}$, is a common constituent of sodium-rich alkaline igneous rocks and is classified a an open-branched single-chain silicate. $M\ddot{o}ssbauer$ spectroscopy of three natural aenigmatite specimens were done and the detailed crystal chemistry was obtained. Fitting of $M\ddot{o}ssbauer$ spectra led to the resolution of nine peaks. They consist of three doublets of $Fe^{2+}/oct$ and one merged peak at low velocity matching to two small peaks at high velocity which were assigned to $Fe^{3+}/tet\;and\;Fe^{2+}/oct$, respectively. Using the peak area for $Fe^{2+}\;and\;Fe^{3+}$ peaks, analytical data were recalculated. Precise assignment of $Fe^{2+}\;and\;Fe^{3+}$ ions in tetrahderal and octahedral sites revealed detailed crystal chemistry of aenigmatite. The existence of significant amounts of $Fe^{3+}/tet$ indicates that $Fe^{3+}$ has preference over $Al^{3+}$ for the tetrahedral sites. Crystal chemistry of aenigmatite (AEN1) yields the formula of $(Na_{3.97}Ca_{0.03})(Ca_{0.11}Mn_{0.59}Fe^{2+}{_{8.07}}Ti_{2.07}Mg_{0.70}Fe^{3+}{_{0.43}}Al_{0.04})(Fe^{3+}{_{0.56}}Al_{0.18}Si_{11.26})O_{40}$.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.5
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• pp.767-772
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• 2011

The purpose of this study was to find out required time for recovery of nutritional disorder by Fe-DTPA treatment in induced Fe-deficient tomato cultivars and to select stable Fe-chelate in high pH of nutrient solution. The pH levels of nutrient solution were amended with 6.0, 7.0, and 8.0. Then Fe-EDTA (Ethylenediaminetetraacetic acid, ferric-sodium salt), Fe-DTPA (Sodium ferric diethylenetriamine pentaacetate), and Fe-EDDHA (Ethylenediamine-N,N-bis (2-hydroxyphenylacetic acid) ferric-sodium salt)) were treated as Fe $2.0mg\;L^{-1}$ concentration. The Fe-DTPA and Fe-EDDHA were stable in the nutrient solution of pH 6.0~8.0 but Fe-EDTA in nutrient solution of pH 8.0 was to become insoluble by 25%. The Fe $2.0mg\;L^{-1}$ as Fe-DTPA was treated for recovery of Fe deficient tomato seedlings. In case of Redyoyo and Supersunroad cultivars, total chlorophyll and Fe contents of leaves were recovered as much as those of normal leaves in 5 days. The Rafito cultivar for complete recovery was taken 7 days. When Fe $2.0mg\;L^{-1}$ as Fe-DTPA was supplied to Fe-deficient tomato seedlings, in geotype, heme oxigenase recovered as much as normal leaves in 24 hours in the Rafito and Redyoyo. However, it was not remarkable difference by elapsed time in the Supersunroad.

• Journal of Korea Foundry Society
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• v.33 no.6
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• pp.233-241
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• 2013

Effect of Fe and Mn contents on the castability of Al-9wt%Si-xMg-yFe-zMn alloy has been studied. The alloy was composed of ${\alpha}$-Al phase, Al+eutectic Si phase, ${\beta}$-Al5FeSi compound and chinese script ${\alpha}$-$Al_{15}(Mn,Fe)_3Si_2$ compound. ${\beta}$-$Al_5FeSi$ and ${\alpha}$-$Al_{15}(Mn,Fe)_3Si_2$ compounds assumed to effect the fluidity and shrinkage behaviors of the alloy during solidification due to the crystallization of ${\alpha}$-$Al_{15}(Fe,Mn)_3Si_2$ and ${\beta}$-$Al_5FeSi$ compounds above eutectic temperature. As Fe and Mn contents of Al-9wt%Si-0.3wt%Mg system alloy increased from 0.15wt% to 0.6wt% and from 0.3wt% to 0.7wt%, fluidity of the alloy decreased by 5.7% and 3.3%, respectively. And as Mg content of Al-9wt%Si-0.45wt%Fe-0.5wt%Mn system alloy increased from 0.3wt% to 0.4wt%, fluidity of the alloy decreased by 8.6%. When Fe content of the alloy increased from 0.15wt% to 0.6wt%, macro shrinkage ratio decreased from 6.1% to 4.1%, and micro shrinkage ratio increased from 0.04% to 0.24%. Similarly, Mn content of the alloy increased from 0.3wt% to 0.7wt%, macro shrinkage ratio decreased from 6.0% to 4.5% and micro shrinkage ratio increased from 0.12% to 0.18%. Judging from the castability of the alloy, Al-9wt%Si-0.3wt%Mg alloy with low content of Fe and Mn, 0.1wt% Fe and 0.3wt% Mn, is recommendable.

• Journal of Korea Foundry Society
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• v.33 no.3
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• pp.103-112
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• 2013

Effect of Fe and Mn contents on the tensile properties of Al-4 wt%Mg-0.9 wt%Si alloy system has been studied. Common phases of Al-4 wt%Mg-0.9 wt%Si alloy system were ${\alpha}$-Al, $Mg_2Si$, ${\alpha}-Al_{12}(Fe,Mn)_3Si$ and ${\beta}-Al_5FeSi$. As Fe content of Al-4 wt%Mg-0.9 wt%Si alloy system increased from 0.15 wt% to above 0.3 wt%, ${\beta}-Al_5FeSi$ compound appeared. When Mn content of the alloy increased from 0.3 wt% to 0.5 wt%, morphology of plate shaped ${\beta}-Al_5FeSi$ compound changed to chinese script ${\alpha}-Al_{12}(Fe,Mn)_3Si$. As Fe content of Al-4 wt%Mg-0.9 wt%Si-0.3 wt%Mn alloy increased from 0.15 wt% to 0.4 wt%, tensile strength of the as-cast alloy decreased from 191 MPa to 183 MPa and, elongation of the alloy also decreased from 8.0% to 6.2%. Decrease of these properties can be explained as the formation of plate shape, ${\beta}-Al_5FeSi$ phase with low Mn/Fe ratio of the alloy. However, when Mn content of Al-4 wt%Mg-0.9 wt%Si-0.3 wt%Fe alloy increased from 0.3 wt% to 0.5 wt%, tensile strength of as-cast alloy increased from 181 MPa to 194 MPa and, elongation of the alloy increased from 6.8% to 7.0%. These improvements attribute to the morphology change from ${\beta}-Al_5FeSi$ phase to chinese script, ${\alpha}-Al_{15}(Fe,Mn)_3Si_2$ phase shape-modified from with high Mn/Fe ratio of the alloy.

• Journal of the Korean Magnetics Society
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• v.8 no.2
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• pp.67-73
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• 1998

Crystallographic and magnetic properties of perovskite $Gd_{1-x}Sr_xFeO_{3-y}$ (x=0.0, 0.5) substituted $Sr^{2+}$ having larger inoic radius than $Gd^{3+}$ at GdFeO$_3$have been studied by x-ary diffraction, M$\ "{o}$ssbauer spectroscopy, and VSM. The cystal structures are found to be orthorhombic with the lattice parameters : $a_o=5.53\;{\AA},\;b_o=5.608\;{AA},\;C_o=7.724\;{\AA}$ for $Gd_{0.5}Sr_{0.5}FeO_{3-y}$ (x=0.0, 0.5) have been investigated over temperature range from 4.2 to 690 K using the M$\ "{o}$ssbauer technique. The Neel temperatuer of $Gd_{1-x}Sr_xFeO_{3-y}$ system is 690 K with x value of 0.0 and 515 K with x value of 0.5. Analysis of M$\ "{o}$ssbauer spectra Mohr's salt analysis for $Gd_{1-x}Sr_xFeO_{3-y}$ demonstrated the existence of the mixed valence states of iron and the coordination state of $Fe^{3+}$ and $Fe^{4+}$ ions. The Corresponding hyperfine parameters for GdFeO$_3$ are compatible with S=5/2 $Fe^{3+}$ in octahedral cooedination.l cooedination.

• Journal of Magnetics
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• v.7 no.1
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• pp.18-20
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• 2002

The charge structures of (LSMO) and of the combined system $(La_{ 0.6}Sr_{0.4}FeO_3$(LSMO) and of the combined system (La_{0.6}Sr_{0.4}MnO_3)_{0.7}(La_{0.6}Sr_{0.4}/FeO_3)_{0.3}$are investigated by using M$\ddot{o}$ssbauer spectroscopy. The antiferromagnetically ordered $(La_{0.6}Sr_{0.4}FeO_3$(LSFO) has possible charges of Fe^{3+} and Fe^{4+}$, which include a low-spin $Fe^{4+}$ state at and above 230 K. The temperature dependences of the M$\ddot{o}$ssbauer spectra for the $(La_{ 0.6}Sr_{0.4}FeO_3$ system and for the combined $(LSMO)_{ 0.7}(LSFO)_{0.3}$ system are fitted as three sets of Zeeman patterns corresponding to $Fe^{3+}$ and $Fe^{4+} below 230 K. At and above 230 K, the fitted M$\ddot{o}$ssbauer spectra for the combined system are the same in all temperature ranges. Above 230 K, $(La_{0.6}Sr_{0.4}FeO_3$ spectrum consists of two sets of six Lorentzians for $Fe^{3+}$ and one line for low spin $Fe^{4+}$. It is worth noting that large fields are induced in the combined system.

• The Korean Journal of Mycology
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• v.21 no.3
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• pp.165-171
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• 1993

The effects of the iron ions for the light-induced mitochondrial $F_0F_1-ATPase$ of Lentinus edodes was studied. The enzyme activity was stimulated up to 202% by 0.1 mM $Fe^{2-}$ ion, but was inhibited by $Fe^{3+}\;and\;Mg^{2+}$. In the presence of 0.5 mM $Mg^{2+}$, the activity also increased 32% by 0.1 mM $Fe^{2+}$ ion, and decreased to a similar extent by $Fe^{3+}$ ion than by only $Fe^{3+}$ ion. Also, the activity was inhibited 53% by 5.0 mM $Fe^{2-}$ ion in the presence of 0.5 mM $Mg^{2+}$ ion and various concentration of $Fe^{3+}$ ion(mM). These results showed that $Fe^{2+}$ strongly stimulated the enzyme activity and its role for the enzyme was independent of $Mg^{2+}$ ion, but was dependent of $Fe^{3+}$ ion. From inactivation of the enzyme by addition of metal chelating agent, EDTA, it is suggested that the enzyme is to be metalloenzyme. The optimal pH and temperature of the enzyme in the presence of 0.1 mM $Fe^{2+}$ was 7.6 and $63^{\circ}C$, respectively.

• Journal of Korea Foundry Society
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• v.33 no.2
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• pp.55-62
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• 2013

Effect of Fe and Mn contents on the castability of Al-4wt%Mg-0.9wt%Si system alloy has been studied. According to the analysis of cooling curve for Al-4wt%Mg-0.9wt%Si-0.3wt%Fe-0.3/0.5wt%Mn alloy, ${\alpha}-Al_{15}(Fe,Mn)_3Si_2$ and ${\beta}-Al_5FeSi$ phases crystallized above eutectic temperature of $Mg_2Si$. Therefore, these phases affected both the fluidity and shrinkage behaviors of the alloy during solidification. As Fe and Mn contents of Al-4wt%Mg-0.9wt%Si system alloy increased from 0.1 wt% to 0.4 wt% and from 0.3 wt% to 0.5 wt% respectively, the fluidity of the alloy decreased by 26% and 33%. When Fe content of the alloy increased from 0.1 wt% to 0.4 wt%, 23% decrease of macro shrinkage and 19% increase of micro shrinkage appeared. Similarly, Mn content of the alloy increased from 0.3 wt% to 0.5 wt%, 11% decrease of macro shrinkage and 14% increase of micro shrinkage appeared. Judging from the castability of the alloy, Al-4wt%Mg-0.9wt%Si alloy with low content of Fe and Mn, 0.1 wt% Fe and 0.3 wt% Mn, is recommendable.