• Journal of the Korean Magnetics Society
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• v.2 no.3
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• pp.244-250
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• 1992

Iron nitride $Fe_4N$ by partial substitution of nitrogen by carbon was prepared by nitriding the iron oxalate whose thermal decomposition gives a carburating atmosphere. Iron oxalates, the precursors, were prepared by precipitation and co-precipitation. The size and shape of the carbonitride particles could be controlled by modifying the conditions of preparation of the oxalate precursor. From the results of electron micrographs, it is clear that the $Fe_4N$ pigment particle maintains the original shape(needle shape) of the starting materials and that it consists of fine unit particles which link together to form a stereo-network structure. An investigation of the $Fe^{II}_3\;Fe^I_{1-x}\;Sn_xN_{1-y}C_y$ solid solution has shown that Sn plays the role of a growth inhibitor of the elementary microcrystallites of the iron carbonitride. The coercive force and saturation magnetization of iron carbonitride obtained from co-precipitated iron oxalate were 500 Oe and 120 emu/g, respectively.

• Journal of Korean Society for Atmospheric Environment
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• v.23 no.5
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• pp.575-584
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• 2007

The adsorption capability of iron phthalocyanine derivatives were investigated by means of X-ray diffractometor (XRD), IR (infrared) spectroscopy, scanning electron microscopy (SEM) and temperature programmed desorption (TPD). According to TPD results, iron phthalocyanine derivatives showed two desorption peaks at low temperature ($100{\sim}150^{\circ}C$) and high temperature ($350{\sim}400^{\circ}C$) indicating that there were two kinds of acidities. Tetracarboxylic iron phthalocyanine (Fe-TCPC) have a stronger desorption peak (chemical adsorption) at the high temperature and a weaker desorption peak (physical adsorption) at the low temperature than iron phthalocyanine (Fe-PC). The specific surface areas of Fe-TCPC and Fe-PC were $26.46\;m^2/g\;and\;11.77\;m^2/g$, respectively. The pore volumes of Fe-TCPC and Fe-PC were $0.14\;cm^3/g\;and\;0.06\;cm^3/g$, respectively. The adsorption capability of triethyl amine calculated by breakthrough curve at 220 ppm of equilibrium concentration was 29.2 mmoL/g for Fe-TCPC and 0.8 mmoL/g for Fe-PC. The removal efficiency of dimethyl sulfide of Fe-TCPC and Fe-PC in batch experiment of 225 ppm of initial concentration were 44.9% and 28.9%, respectively. The removal efficiency of trimethyl amine of Fe-TCPC and Fe-PC in batch experiment of 118 ppm of initial concentration were approximately 100.0% and 33.9%, respectively.

• Archives of Pharmacal Research
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• v.22 no.3
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• pp.288-293
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• 1999

Postabsorptive serum iron level was determined after oral administration of the compounds to human. In serum and whole blood, $Fe^{3+}$ was measured by ion chromatography (IC) using a pyridine-2,6-dicarboxylic acid (PDCA) as an eluent. The serum sample solutions were pretreated with I N HCI and 50% TCA. The whole blood sample solutions were treated with 3 N HCI for 30 min at $125^{\circ}C$. The limit of detection (LOD) of the IC technique is $0.2 {\mu}M$ for$Fe^{2+}$and 0.1 $\mu$M for $Fe^{3+}$. The area under concentration (AUC) can be obtained by the above analytical condition. In addition, to compare the stability of $Fe^{2+}$ to that of $Fe^{3+}$ in pharamaceutical preparations, accelerated stability test was carried out. After storing the samples under $40^{\circ}C$, 75%RH in light-resistant container for various time intervals, the contents of iron of different valencies were determined separately by the IC technique and the change and/or the interchange of among those iron species in preparations was investigated. Iron raw materials are stable, but $Fe^{2+}$ in$Fe^{3+}$ source materials was slightly converted to $Fe^{3+}$ by oxidation. $Fe^{2+}$ in$Fe^{3+}$ source raw materials and $Fe^{3+}$ in $Fe^{2+}$ raw materials are determined as impurities. Therefore, IC technique is found to be an appropriate method for comparative evaluation of dissimilar bioavailability of $Fe^{2+}$ and $Fe^{3+}$, stability of $Fe^{2+}$ and $Fe^{3+}$ raw materials and preparations.

• The Korean Journal of Ceramics
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• v.4 no.2
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• pp.156-161
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• 1998

We have measured changes of the non-stoichiometry, $\Delta\delta$, in Fe-doped nicked oxide , by thermogravimetry for four iron fractions, x=0.01, 0.031, 0.057 and 0.10, and three temperatures, T=1273, 1373 and 1473 K. The obtained data can be modelled by a defect structure in which substitutional trivalent iron ions, FeNi, are compensated by cation vacancies, $V_{Ni}$", and (4:1)-clusters. These clusters consist of tetravalent interstitial iron, $Fe_i\;^4$

• Journal of the Korean Ceramic Society
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• v.35 no.3
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• pp.239-244
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• 1998

Iron complexes were prepared using ferric nitrate and ethylene glycol as starting materials and the ul-trafine ${\alpha}-Fe_2O_3$ particles with the sizes smaller than 200nm were obtained by the pyrolysis of iron com-plexes at over $350^{\circ}C$ In addition the decomposition mechanism of the synthesized iron complexes was in-vestigated by differential scanning calorimeter X-ray diffractometer and IR spectrometer. Transmission electron microscopy and BET method were performed to analyze the effects of ferric nitrate contents and reaction temperatures on the size and shape of the particles.

• Journal of Photoscience
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• v.1 no.2
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• pp.83-88
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• 1994

The synergic effect of iron plus blue light on the peroxidation of membrane lipid was investigated, using liposomes made of phospholipid. While strong irradiation did not affect Fe$^{+2}$-promoted lipid peroxidation that turned out to be O$_2$-dependent, ferric iron in bright light exerted a pronounced effect on the initiation of lipid peroxidation: this combined action of light and Fe$^{+3}$ on liposomal membranes was apparently independent of O$_2$. When liposomal samples containing Fe$^{+3}$ were subjected to irradiation, some portions of Fe$^{+3}$ were converted into Fe$^{+2}$. The extent of the Fe$^{+3}$-Fe$^{+2}$ conversion increased with increasing time of irradiation, which resembled the dependence of Fe$^{+3}$-promoted lipid peroxidation on irradiation. Further, it was observed that the effect of irradiation in liposomal samples containing Fe$^{+2}$ was strikingly mimicked by that of Fe$^{+2}$ addition to the same samples. The obligatory requirement of a suitable Fe$^{+3}$/Fe$^{+2}$ ratio for the genesis of iron-dependent lipid peroxidation, a controversial proposition, was also confirmed by the observation that lipid peroxidation was substantially enhanced by the addition of a mixture of Fe$^{+3}$ and Fe$^{+2}$, as compared to the addition of Fe$^{+3}$ or Fe$^{+2}$ alone. The results obtained in this study not only suggest that light acts as an effector for initiating lipid peroxidation, when Fe$^{+3}$ is present in membrane systems, but also imply that any chemical or physical factor that influences the redox states of iron in membranes can play a role in lipid peroxidation reactions.

• Journal of Nutrition and Health
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• v.40 no.5
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• pp.428-434
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• 2007

Cham-dang-gui (Angelica gigas nakai) has been used in traditional Korean medicine to treat hemotological disorders. The purpose of this study is to investigate the hematological effects of water extracts of Cham-dang-gui in rats with anemia induced by iron-free diets. Rats were divided into two groups, a regular diet group (RD) and an iron-free diet group (FeD). The iron-free diet group was then subdivided into the following three treatment groups: saline (1.0 ml/kgBW/day, FeDS), Cham-dang-gui (1.0 g/kgBW/day, FeDA), and iron (iron succinylate 14 mg/kgBW/day, FeDFe) groups. Rats were fed an iron-free diet for 6 weeks to induce iron-deficient anemia, and subsequently underwent the treatments, during which they were fed an iron-free diet for 3 weeks followed by a regular diet for 3 weeks. Body weights of the iron-diet groups (FeDS, FeDA, FeDFe) were lower than that of RD group. The blood levels of Hgb, Hct, MCV, MCH and TIBC were significantly higher in RD and FeDFe groups than those of other groups. The water extract of Cham-dang-gui with iron-free diet has no hematological effects. A regular diet followed by iron-free diets significantly increased blood levels of Hgb, Hct, and MCH.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09b
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• pp.1187-1188
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• 2006

This paper compares the effect of using different types of iron powders for the preparation of $Sm_2Fe_{17}$ by calciothermic reduction-diffusion (CRD). Three types of iron powder were used: carbonyl, sponge and water atomized. The results show that, when immediately nitrogenated after the CRD process, $Sm_2Fe_{17}$ prepared from sponge and water atomized iron powders yield $Sm_2Fe_{17}N_3$-magnets with a high degree of texture. However, after a suitable treatment with hydrogen followed by nitrogenation, $Sm_2Fe_{17}$-powders made from Carbonyl iron produce magnets with the best quality regarding coercivity, remanence and degree of texture.

• Resources Recycling
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• v.13 no.5
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• pp.45-50
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• 2004

To investigate the characteristics of phases formed in iron carbides, super iron carbide was synthesized from hematite fines with $CO-H_2$ gas mixture after reduction under $H_2$ gas at $600^{\circ}C$. Before carburization, the surface of iron powder reduced was pre-treated in the atmosphere of 0.05 vol% $NH_3$-Ar. The synthesized iron carbides were comprehensively explored by C/S analyzer(Low C/S determinator), M$\"{o}$ssbauer spectroscopy, X-ray diffraction patterns(XRD), scanning electron microscopy(SEM), transmission electron microscopy(TEM), and Raman spectroscopy at various reaction time of 5, 10, 15, 20, 25, 30, and 35 min, respectively. By adding a small amount of $NH_3$ gas, the super iron carbides containing 10 wt% carbon were synthesized, and its addition stabilized iron carbides. It was found that the $NH_3$ treatment played a major role in the formation of iron carbide without decomposition($Fe_3C{\to}$3Fe+C) of iron carbides and precipitation of free carbon. It also succeed to synthesize super iron carbide, $Fe_5C_2$, as a stable single phase without involving Fe and $Fe_3C$ phases.

• Resources Recycling
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• v.13 no.6
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• pp.9-15
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• 2004

The optimum conditions were studied for the preparation of transparent iron oxide with the air oxidation of FeOOH. The FeOOH obtained by mixing NaOH and FeSO$_4$ solution in various conditions such as R(=2NaOH/FeSO$_4$), FeSO$_4$ concentration. reaction temperature and air flow rate. When the FeSO$_4$ increased gradually, the concentration of iron ion in the solution became high. So, particle size increased precipitating Fe$_3O_4$. Goethite dehydrate at about 200$^{\circ}C$ and ended the reaction at about 320$^{\circ}C$ forming hematite. The lower the reaction temperature was, the shorter the particle length of goethite and particle size decreased. When the flow rate of air as an oxidant increased, the amount of dissolved oxygen in the solution increased, which made oxidation rate increased. And then particle size of goethite decreased.