• Korean Journal of Food Science and Technology
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• v.25 no.1
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• pp.46-51
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• 1993

The inactivating effect of iron(II)-ascorbate complex (Fe-Asc) on various phages was previously reported. This paper describes the molecular target in the phage virion attacked by Fe-Asc. The effect of Fe-Asc on protein was investigated with bovine serum albumin and the structural protein of phage J1. There were no differences in the SDS-polyacrylamide gel electrophoresis (patterns of these two proteins when either they were treated) with Fe-Asc or not. Also, there were no changes in the amino acid composition and ultraviolet spectrum of the proteins. The effects of Fe-Asc on DNA was investigated with pUC18 DNA, M13mpB DNA and ${\lambda}$ DNA as well as DNA from phage J1. Fe-Asc caused initially nicking of the subsequently form of pUC18 DNA to yield the open circular form and then subsequently the linear form. Strand breaks were also confirmed with M13mp8 DNA and ${\lambda}$ DNA as well as J1 DNA. The results indicate that the strand breaks in phage DNA could be responsible for the inactivation of phages by Fe-Asc.

• Transactions of the Korean hydrogen and new energy society
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• v.18 no.2
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• pp.124-131
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• 2007

Methane is partially oxidized to produce the syngas by the lattice oxygen of metal oxides in the absence of gaseous oxygen. The present work deals with ferrite including copper component, which does not chemisorb methane, to investigate the suppression of the carbon deposition during the reduction of metal oxides by methane. Iron-based oxides of $Cu_xFe_{3-x}O_4$(X=0.25, 0.5, 1.0) was synthesized by the co-precipitation method. Thermogravimetric Analysis(TGA) was used to observe the isothermal reduction behavior of $Cu_xFe_{3-x}O_4$ and $Fe_3O_4$ at $600-900^{\circ}C$ under methane atmosphere. The crystal structures of reduced specimens were characterized by X-rays powder diffraction(XRD) technique. From the analyses of TGA, it is concluded that the reduction kinetics of $CuFe_2O_4$ was the fastest among $Fe_3O_4$ and $Cu_xFe_{3-x}O_4$(X=0.25, 0.5, 1.0). The X-ray diffraction analyses indicated that $Cu_xFe_{3-x}O_4$ was decomposed to Cu and $Fe_3O_4$ phase at $600^{\circ}C$ and was reduced to Cu and Fe phase at $800^{\circ}C$. $Fe_3O_4$, which was reduced at $900^{\circ}C$, showed Fe, graphite and $Fe_3C$ phases. On the contrary, $Cu_xFe_{3-x}O_4$ does not show the graphite or $Fe_3C$ phases. This results infer that Cu component suppress the carbon deposition on Cu-ferrite.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.9 no.5
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• pp.486-492
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• 1999

The purpose of this research was to find out what is the dominant factor determining the $H_{ex}$ and the $H_C$ of Mn-Ir/Ni-Fe multilayers with different buffer layers. Regardless of (111) texture of Mn-Ir layer, all samples showed over the $H_{ex}$ of 155 Oe. We found out the $H_{ex}$ and the $H_C$ of Mn-Ir/Ni-Fe multilayers depend on interface morphology and grain size of Mn-Ir layer at the interface between Mn-Ir and Ni-Fe layers. The dependence of magnetroesistance ratio and coupling field on the thickness of ferromagnetic layer, thickness of Cu layer and different buffer layers have been studied. Maximum magnetoresistance ratio appeared for the sample Ta(5 nm)/Mn-Ir(10 nm)/Ni-Fe(7.5 nm)/Cu(2 nm)/Ni-Fe(6 nm)/Ta(5 nm)/Si. Magnetoresistance ratio may be related to grain of ferromagnetic layer. Coupling field may be related to the roughness and the grain size of ferromagnetic layer in the spin-valve multilayers.

• Resources Recycling
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• v.7 no.3
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• pp.3-10
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• 1998

Simulated waste liquid containing 50 ppm cobalt ion was treated by adsorbing colloidal flotation using Fe(III) or Al(IlI) as flocclant and a sodium lamyl sulfate as a collector. Parameters such as pH, surfactant concentration, Fe(III) or Al(III) concentration, gas flow rate, etc., W앙e considered. The flotation with Fe(III) showed 99.8% removal efficiency of cohalt on the conditions of initial cobalt ion concentration 50 ppm, pH 9.5, gas flow rate 70 ml/min, and flotation time 30 min. When the waste solution, was treated with 35% $H_2O_2$ prior to adsorbing colloidal flotation, the optimal pH for removing cobalt shifted m to weak alkaline range and flotation could be applied in wider range of pH as compared to non-use of $H_2O_2$. Additional use of 20 ppm Al(III) after precipitation of 50 ppm Co(II) with 50 ppm Fe(III) made the optimal pH range for preferable flotation w wider. Foreign ions such as, $NO_3^-$, $SO_4^{2-}$, $Na^+$, $Ca^{2+}$ were adopted and their effects were observed. Of which sulfate ion was f found to be detrimental to removal of cob퍼t ion by flotation. Coprecipitation of Co ion with Fe(III) and Al(III) resulted in b better removal efficiency of cobalt IOn 피 the presence of sulfate ion.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.2
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• pp.184-190
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• 2005

A new VFAs production process from sewage sludge using Fenton's oxidation was investigated. Optimum concentrations of $H_2O_\;and\;Fe^{2+}$ as well as optimum reaction temperature for VFAs production were studied. In the presence of $Fe^{2+}$ as catalyst, the VFAs formation rate increased about 4 times compared to $H_2O_2$ oxidation process without $Fe^{2+}$. Optimum concentrations of $H_2O_2$ and $Fe^{2+}$ were 0.62 M and 0.007 M, respectively. VFAs formation reaction proceeded rapidly within 1 min and VFAs formed degraded partly to acetic acid and $CO_2$, which exhibited series reaction characteristics. Based on the economic aspect, reaction temperature of $25^{\circ}C$ and 10 min of reaction time were thought to be proper reaction conditions. The effect of initial pH in the range of $3{\sim}6.3$ on the VFAs formation was not observed.

• Korean Chemical Engineering Research
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• v.49 no.6
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• pp.804-809
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• 2011

Tubular $Ba_{0.5}Sr_{0.5}Co_{0.8}Fe_{0.2}O_{3-${\delta}$}$ membranes were prepared by extrusion. TGA results of green body membrane after extrusion showed three successive weight losses due to decomposition of organic additives and carbonate. Drying shrinkage rate of tubular $Ba_{0.5}Sr_{0.5}Co_{0.8}Fe_{0.2}O_{3-${\delta}$}$ membranes was no change after 68 h and higher in the membrane with large outer diameter. XRD and SEM results showed the sintered membranes were the single phase structure and dense. The stoichiometric molar ratio agreed well with composition ratio calculated by EDS results for $Ba_{0.5}Sr_{0.5}Co_{0.8}Fe_{0.2}O_{3-${\delta}$}$ membrane. Radial crushing strength of tubular $Ba_{0.5}Sr_{0.5}Co_{0.8}Fe_{0.2}O_{3-${\delta}$}$ membrane with 0.95 mm thickness was 5.7 kgf/$mm^2$ and the oxygen permeation rate of same membrane was 146.85 mL/min ($Jo_2$=2.33 mL/$min{\cdot}cm^2$) at $950^{\circ}C$. Therefore, it was known that use of vacuum pump was more effective than that of sweep gas to obtain higher oxygen permeation flux.

• Asian-Australasian Journal of Animal Sciences
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• v.15 no.10
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• pp.1469-1474
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• 2002

This study was designed to evaluate the influence of a single or double dose of Fe dextran with organic trace mineral supplementation on the performance of piglets from dams fed diets with either inorganic (ITM) or organic trace minerals (OTM). It also determined the effect of the source of the trace minerals on the reproductive performance of sows. The trace mineral premixes were prepared using metal proteinates and the corresponding inorganic salts for the OTM and the ITM, respectively. Each mineral premix provided 100 ppm Fe/175 ppm Fe, 35 ppm Cu/170 ppm Cu, 90 ppm Zn/120 ppm Zn, and 40 ppm Mn/35 ppm Mn when added at 0.20% in sows /weaned pigs' diets, respectively. The first dose of Fe dextran was administered to piglets at 3 d and the second dose at 10 d after birth. One dose of Fe dextran supplied 100 mg of Fe. A total of 16 gestating sows (Landrace${\times}$Yorkshire) in parities 2 to 4 were randomly allocated to four treatments: 1) diet with ITM/one dose of Fe dextran to piglets, 2) diet with ITM/two doses of Fe dextran to piglets, 3) diet with OTM/one dose of Fe dextran to piglets, and 4) diet with OTM/two doses of Fe dextran to piglets. The total born alive, weaned, body weight at birth and at weaning were not affected by the sow's dietary treatment. Although organic trace mineral supplementation tended to increase the milk Fe content (p<0.10) at 7 d postpartum, piglets in all treatments performed equally from birth to weaning. The double doses of Fe dextran neither improved the average daily gain (ADG) nor influenced the survival of piglets from birth to weaning (21 d). Results suggest that a single dose of Fe dextran given to suckling pigs is adequate to sustain their needs for growth throughout the lactation period (21 d). Furthermore, there was a 21% improvement in both the ADG and the average daily feed intake (ADFI) (p<0.05) in weaned pigs fed diets with OTM. Cu and Fe in the liver (p<0.01), and Zn in both the bone (p<0.01) and the serum (p<0.01) were higher in piglets fed OTM than in those fed ITM. It would be concluded that single dose of Fe dextran administration with organic trace mineral supplementation show similar growth performance compared to 2 dose Fe dextran administration with inorganic mineral supplementation in young pigs.

• Journal of Powder Materials
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• v.24 no.4
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• pp.298-301
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• 2017

In the present work, we use multiwall carbon nanotubes (MWCNT) as the starting material for the fabrication of sintered carbon steel. A comparison is made with conventionally sintered carbon steel, where graphite is used as the starting material. Milling is performed using a horizontal mill sintered in a vacuum furnace. We analyze the grain size, number of pores, X-ray diffraction patterns, and microstructure. Changes in the physical properties are determined by using the Archimedes method and Vickers hardness measurements. The result shows that the use of MWCNTs instead of graphite significantly reduces the size and volume of the pores as well as the grain size after sintering. The addition of $Y_2O_3$.to the Fe-MWCNT samples further inhibits the growth of grains.

• Korean Journal of Materials Research
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• v.15 no.12
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• pp.760-764
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• 2005

The influences of the oxidant($O_2\;and\;O_3$) on the FeOOH formation were studied with fixed $FeSO_4{\cdot}7H_2O$ concentration (0.5M) and NaOH equivalent ratio(0.5). The characteristics of the synthesized powders were evaluateed by XRD, and equantitative phase analysis. $\alpha-FeOOH$ (Geothite) and/or $\gamma-FeOOH$ was promoted when $O_3$ was used as a oxidant which is stronger oxidizing agent than $O_2$.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.378-378
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• 2010

We report the electronic structure of CoFeO-R (R=Hf, La, Nb) thin films studied by x-ray absorption spectroscopy (XAS). These ferrites thin films were prepared by pulsed laser deposition method and characterized by XAS measurements at O K-, Co and Fe L-edges. The O K-edge spectra suggest that there is a strong hybridization between O 2p and 3d electrons of transition metal cations and Fe $L_{3,2}$-edge spectra indicate that Fe-ions exist in $Fe^{2+}$ with tetrahedral site of the spinel structure. Divalent Co ions is also distributed in tetrahedral site with rare earth ions goes to octahedral sites of spinel structure. X-ray magnetic circular dichroism (XMCD) is also used to explain the symmetry and magnetic nature dependence on rare-earth ions.