• Bulletin of the Korean Chemical Society
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• v.23 no.7
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• pp.943-947
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• 2002

The two reactions between iron ion (Fe3+ ) and o-chlorophenylfluorone (o-CPF) and copper ion (Cu2+ ) and o-CPF are sensitive at pH 6 in the presence of Triton X-100. We have determined the formation constants of the complexes by the spectral correction technique. Because of the poor selectivity of o-CPF to metals, the competition coordination of only the iron ion from the Cu-o-CPF complex was found and applied to the selective detection of iron traces by the Selective Competition Coordination Determination (SCCD) approach.The analysis of several samples shows that the relative standard deviations are less than 5.0% and the recovery of iron ions between 94.5% and 106%.

• Transactions of Materials Processing
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• v.25 no.6
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• pp.366-372
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• 2016

Recently, the amount of spring usage is on the increase in the automotive and aircraft parts industries as well as home appliances. Manufacture of spring reflects a need for diversification, mass production and high precision. Therefore it is very important to know the bending method and forming technique according to the shape of spring. In this study, to find the optimal bending method for the motor spring, the FE-simulation was executed using orthogonal array. The design parameters are wire length, length of vibration and feed rate. Then, the optimal combination of design parameters was suggested using ANN technique.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.11b
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• pp.766-771
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• 2001

The package used to transport radioactive materials, which is called by cask, must be safe under normal and hypothetical accident conditions. These requirements for the cask design must be verified through test or finite element analysis. Since the cost for FE analysis is less than one for test. the verification by FE analysis is mainly used. But due to the complexity of mechanical behaviors. the results depends on how users apply the codes and it can cause severe errors during analysis. In this paper, finite element analysis is carried out for the 9 meters free drop and the puncture condition of the hypothetical accident conditions using LS-DYNA3D and ABAQUS/Explicit. We have investigated the analyzing technique for the free drop impact test of the cask and found several vulnerable cases to errors. The analyzed results were compared with each other. We have suggested a reliable and relatively simple analysis technique for the drop test of spent nuclear fuel casks.

• Journal of the Korean Magnetics Society
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• v.5 no.5
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• pp.538-542
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• 1995

The etching characteristics of magnetic thin films of permalloy and Fe-based alloys are investigated. The thin films are fabricated by rf magnetron sputtering and the substrates used are silicon and glass. Etching is done by ion beam technique and the main process parameters investigated are beam voltage, beam current and accelerating voltage. The etch rate of the magnetic films is proportional to the beam current, but it is not directly related to the accelerating voltage and beam voltage. The dependence of etch rate on the process parameters can be explained by ion current density. It is found that the ion beam etching is effective in obtaining well-developed micro-patterns on the permalloy and Fe- based magnetic thin films.

• 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 the Korean Chemical Society
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• v.43 no.4
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• pp.423-429
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• 1999

A spectrofluorimetric method for the determination of Fe(III) in aqueous solution with 4,5-dihydroxy-1,3-benzenedisulfonic acid(Tiron) as a fluorimetric reporter was developed. Tiron, which is very soluble in water,is a good fluorimetric reagent. However, when Tiron was complexed with Fe(III), the fluorescent intensity was decreased proportionally with the concentration of Fe(III) by a quenching effect. The excitation and fluorescene wavelength of Tiron showing the quenching effect by Fe(III) at pH 4.5 were 312 nm and 341 nm, respectively. The highest sensitivities were shown at Tiron concentration of $1.0{\times}10^{-2}M$. To enhance the quenching effect, the Fe(III)-Tiron complex solution was heated to 80$^{\circ}C$ for 90 minutes. As for Fe(III), the most interfering ion was Cu(II). The interference effects could be mostly eliminated by pH adjustment or by adding EDTA. The concentration ranges showing the linear response to Fe(III) was from $5.0{\times}10^{-7}M\;to\;6.0{\times}10^{-5}M$ With this proposed method, the detection limits of Fe(III) was $2.8{\times}10^{-6}M$. Recovery of Fe(lII) in a synthetic sample was almost quantitative. Based on experimental results, it is proposed that the above technique can be applied to the practical determination of Fe(III).

• 제어로봇시스템학회:학술대회논문집
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• 1997.10a
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• pp.1750-1753
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• 1997

This paper describes how the directivity pattern of the back-scattered sound pressure is distributed when a plane acoustic wave is incident on a righid spherical shell underwater. A coupled Finite Element-Boundary Element mehtod is developed as numerical technique. The result of the coupled FE-BE method is agreed with theoretical solution for algorithmic confirmation.

• Proceedings of the Korean Magnestics Society Conference
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• 2015.05a
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• pp.136-136
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• 2015

• Journal of Electrical Engineering and Technology
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• v.2 no.2
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• pp.216-220
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• 2007

This paper deals with the characteristic analysis of the single phase switched reluctance motor based on the converter coupled FE analysis. The converter comprises a rectifier, LC filter and switching power device. A computational technique for the converter coupled FE analysis is introduced and its validity is proven by the experiment.

• Resources Recycling
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• v.2 no.2
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• pp.27-38
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• 1993

In this study, we investigated the grinding and sedimentation(elutriation) process of the dusts for the effective separation of high purity iron and iron oxides. For characterization of the dust, particle size distribution and chemical composition, were examined. The results obtained in this study may be summarized as follows : 1. The converter CF(clarifier) dust of the Pohang 1st, 2nd steel making factory and EC(Evaporation Cooler), EP(Eltrostatic precititator) dust of the Kwangyang 2nd steel making factory are composed $\alpha$-Fe(21~50%), FeO(wustite)$Fe_3$$O_4$(magnetite), $Fe_2$$O_3$, CaO, $Al_2$$O_3$, $SiO_2$, and etc. 2. Pure iron has ductile characteristic in nature, particle size of the pure iron increase by increasing the grinding time. On the other hand, it is conformed that bo고 particles of hematite and magnetite become less than 325 mesh after 10 minutes grinding. 3. By applying the elutriation technique for the EC dust of the Kwangyang 2nd steel making factory, the iron powder of high content more than 99.17% of pure Fe was recovered with 37.8% yield at grinding time for 40 minutes. 4. By applying the elutriation technique for the CF dust of the Pohang 2nd steel making factory, the iron powder of high content more than 98.38% of pure Fe was recovered with 44.42% yield at grinding time for 40 minutes. 5. When magnetic separation was performed using plastic bonding magnet of 70 gauss, more than 98% Fe grade of iron powder was recovered in the size range +65 -200 mesh but the recovery of it was low.