• Analytical Science and Technology
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• v.7 no.4
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• pp.493-504
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• 1994

The morphology and structure of precipitates of formed in Nb steels were investigated using SEM, TEM and XRD. The quantitative analysis of the precipitates was performed by ICP-AES. The potentiostatic etching method was employed as an extraction method using 10% AA-methanol and 15% Na-citrate electrolytes. The two selected potentials relative to SCE(Standard Calomel Electrode), -100mV in 10% AA-methanol solution and -250mV in 15% Na-citrate solution were found to be effective for the extraction. XRD analysis showed that composition of Nb carbonitride in Nb-steel(0.01% C-0.7% Nb-0.004N) was $NbC_{0.65}N_{0.2}$.

• Economic and Environmental Geology
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• v.8 no.3
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• pp.117-124
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• 1975

Wet chemical analysis (for $MnO_2$, MnO, and $H_2O$(+)) and electron microprobe analysis (for $Fe_2O_3$ and PbO) give $MnO_2$ 74.91, MnO 11.33, $Fe_2O_3$ (total Fe) 4.19, PbO 0.03, $H_2O$ (+) 9.46, sum 99.92%. 'Available oxygen determined by oxalate titration method is allotted to $MnO_2$ from total Mn, and the remaining Mn is calculated as MnO. Traces of Ba, Ca, Mg, K, Cu, Zn, and Al were found. Li and Na were not found. The existence of (OH) is verified from the infrared absorption spectra. The analysis corresponds to the formula $Mn^{4+}{_{4.85}}(Mn^{2+}{_{0.90}}Fe^{3+}{_{0.30}})_{1.20}O_{8.09}(OH)_{5.91}$, on the basis of O=14, 'or ideally $Mn^{4+}{_{5-x}}(Mn^{2+},Fe^{3+})_{1+x}O_{8}(OH)_{6}$ ($x{\approx}0.2$). X-ray single crystal study could not be made because of the distortion of single crystals. But the x-ray powder pattern is satisfactorily indexed by an orthorhombic cell with a 9.324, b 14.05, c $7.956{\AA}$., Z=4. The indexed powder diffraction lines are 9.34(s) (100), 7.09(s) (020), 4.62(m) (200, 121), 4.17(m) (130), 3.547(s) (112), 3.212(vw) (041), 3.101(s) (300), 2.597(w) (013), 2.469(m) (331), 2.214(vw)(420), 2.098(vw) (260), 2.014 (vw) (402), 1.863(w) (500), 1.664(w) (314), 1.554(vw) (600), 1.525(m) (601), 1.405(m) (0.10.0). DTA curve shows the endothermic peaks at $250-370^{\circ}C$ and $955^{\circ}C$. The former is due to the dehydration: and oxidation forming$(Mn,\;Fe)_2O_3$(cubic, a $9.417{\AA}$), and the latter is interpreted as the formation of a hausmannite-type oxide (tetragonal, a 5.76, c $9.51{\AA}$) from $(Mn,\;Fe)_2O_3$. Infrared absorption spectral curve shows Mn-O stretching vibrations at $515cm^{-1}$ and $545cm^{-1}$, O-H bending vibration at $1025cm^{-1}$ and O-H stretching vibration at $3225cm^{-1}$. Opaque. Reflectance 13-15%. Bireflectance distinct in air and strong in oil. Reflection pleochroism changes from whitish to light grey. Between crossed nicols, color changes from yellowish brown with bluish tint to grey in air and yellowish brown to grey through bluish brown in oil. No internal reflections. Etching reactions: HCl(conc.) and $H_2SO_4+H_2O_2$-grey tarnish; $SnCl_2$(sat.)-dark color; $HNO_3$(conc.)-grey color; $H_2O_2$-tarnish with effervescence. It is black in color. Luster dull. Cleavage one direction perfect. Streak brownish black to dark brown. H. (Mohs) 2-3, very fragile. Specific gravity 3.59(obs.), 3.57(calc.). It occurs as radiating groups of flakes, flower-like aggregates, colloform bands, dendritic or arborescent masses composed of fine grains in the cementation zone of the supergene manganese oxide deposits of the Janggun mine, Bonghwa-gun, southeastern Korea. Associated minerals are calcite, nsutite, todorokite, and some undetermined manganese dioxide minerals. The name is for the mine, the first locality. The mineral and name were approved before publication by the Commission on New Minerals and Mineral Names, I.M.A.

• Clean Technology
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• v.28 no.2
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• pp.103-109
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• 2022

Nd-Fe-B waste permanent magnet contains about 20~30% rare earth elements and about 60~70% iron elements, and the rare earth and iron components were recovered through sulfuric acid leaching and fractional crystallization. Oxidation roasting was not performed for separation and recover of the rare earth and iron elements. The leaching characteristics were confirmed by using as variables the sulfuric acid concentration and the mineral solution concentration ratio. Sulfuric acid leaching was carried out for 3 hours for each sulfuric acid concentration. The leached solid phase was characterized for its crystalline phase, composition, and quantitative components by XRD and XRF analysis, and the filtrate was analyzed for components by ICP analysis. With sulfuric acid leaching at 3M sulfuric acid concentration, neodymium compounds were formed, the iron content was the least, and the recovery rate was high. After the filtrate remaining after sulfuric acid leaching was subjected to fractional crystallization through evaporation and concentration, the neodymium component was found to be concentrated 7.0 times and the iron component 2.8 times. In this study, the recovery rate of waste permanent magnets through sulfuric acid leaching and a fractional crystallization method without an oxidation and roasting process was confirmed to be about 99.4%.

• Journal of the Korean Society for Nondestructive Testing
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• v.20 no.4
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• pp.314-321
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• 2000

A gap between a $Al_2O_3/Fe$ thermite and lower head vessel is formed in the lower-plenum arrested vessel attack(LAVA) experiment which is the 1st phase study of simulation of naturally arrested vessel attack in vessel(SONATA-IV). The gap measurement using a conventional ultrasonic method would be lack of a reliability due to the structure complexity and the metallurgical grain size change of the lower head HAZ occurred by a thermite $Al_2O_3/Fe$ melt or a $Al_2O_3$ melt at $2300^{\circ}C$. The grain echoes having false signals and lower S/N ratio signals are detected due to a multiple scattering, a mode conversion and an attenuation of a ultrasonic resulted from at the interface of increased grain size zone. In this test, the signals pattern was classified to understand the behavior of the ultrasonic in a multi-layer specimen of solid-liquid-solid of assuming that the thermite and the lower head vessel is immersed. The polarity threshold algorithm of frequency diversity gives us the enhancement about 6dB of the ratio S/N.

• Nutritional Sciences
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• v.7 no.4
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• pp.247-253
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• 2004

This study has investigated the effect of dietary attitudes on nutritional status of nurses living in Kyungnam province. A total of 249 muses working at hospitals in the Kyungnam area participated in this study. The general characteristics and dietary attitudes of the subjects were surveyed using a self-administered questionnaire, and nutrient intakes were examined using one day 24-hour recall method from November 14 to December 20, in 2001. The data of nutrient intakes were analyzed by the Computer Aided Nutritional Analysis Program and then the diet quality was estimated using the Index of Nutritional Quality (INQ). The subjects were classified as the high score group (17.3 %), medium score group (54.2%), and low score group (28.5%) based on dietary attitude score. The results were as follows: Average age of subjects was 27.1 years old, average nursingexperience was 5.7 years, and 70.7% of the subjects graduated from a junior college. The rate of shift work (45.4%) and non-shift work (54.6%) were similar. The average score on dietary attitudes in thehigh score group was 78.8, and those in he medium score group and in the low score group were 58.6 and 40.8 out of 100 points respectively. The average intake of energy (p < 0.001), carbohydrate (p < 0.001), protein (p < 0.05), animal protein (p < 0.01), animal fat (p < 0.05), vitamin $B_1$ (p < 0.01), vitamin $B_2$ (p < 0.0l), niacin (p < 0.001), Ca (p < 0.001), Fe (p < 0.001), animal Fe (p < 0.01), P (p < 0.001), and crude fiber (p < 0.00l), were significantly higher in the high score group than those in the medium score group and low score group. In the high score group, the average intake of protein, vitamin $B_1$, niacin, vitamin C and P were above 125% of the Korean RDA, and in medium score group, those of vitamin C and P, and in low score group, that of vitamin C were above 125% of the Korean RDA. In the high score group, nutrient of intake below 75% of the Korean RDA was Ca, and those in medium score group were vitamin $B_2$, Ca, and Fe, and those in low score group were energy, vitamin $B_2$, Ca and Fe. The intake ratio of Ca and P showed an unbalanceof 1:2, and that of animal protein/plant protein, and that of animal fat/plant fat were high (1.45-1.64) in all group;. The dietary attitude had a positive correlation (p < 0.00l) with nutrition intake except vitamin A and vitamin C.

• Journal of Korean Society of Environmental Engineers
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• v.37 no.12
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• pp.705-711
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• 2015

Degradation of 2,6-Dichlorophenol (DCP) using liquid ferrate(VI) synthesized by wet oxidation method has been studied. Several parameters such as pH (acid, base and neutral), DCP initial concentration, ferrate dosage, and temperature have been examined to determine the optimal experimental conditions. The ferrate(VI) has useful properties such as strong oxidizing power and selectivity and generates a non-toxic end product, Fe(III). Ferrate ion reduced rapidly to Fe(III) and oxygen in acidic and neutral conditions. The experimental results showed the higher DCP degradation efficiency in the neutral condition than in the acidic and basic conditions. The oxidation of DCP strongly depended on the dosage of ferrate added to the reactor and DCP initial concentration. With increasing of ferrate dosage the degradation efficiency of DCP increased, while the degradation efficiency of DCP decreased with increasing of DCP initial concentration. The effect of temperature has been tested at 4 different levels (10, 25, 35, and $50^{\circ}C$). The optimal temperature was obtained in $25^{\circ}C$ and degradation efficiency decreased as the temperature increased in the range from $25^{\circ}C$ to $50^{\circ}C$. The DCP degradation pathways were studied and proposed based on the intermediate products identified by GC/MS analysis.

• Applied Chemistry for Engineering
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• v.19 no.4
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• pp.382-387
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• 2008

$Ba_{0.5}Sr_{0.5}Co_{0.8}Fe_{0.2}O_{3-{\delta}}$ oxide was synthesized by polymerized complex method. Dense membrane of perovskite oxide was prepared using as-prepared powder by pressing and sintering at $1080^{\circ}C$. Leakage test was conducted on the membrane sealed by gold ring, Pyrex ring or Pyrex powder as a sealing material. The oxygen permeation flux of $Ba_{0.5}Sr_{0.5}Co_{0.8}Fe_{0.2}O_{3-{\delta}}$ membrane increased with increasing temperature and was $0.74mL/min{\cdot}cm^2$ at $900^{\circ}C$. In the case of the membrane applied by sealing material, oxygen permeation flux of the membrane using gold ring at $950^{\circ}C$ was higher than that using Pyrex materials because the undesired spreading of Pyrex glass materials in the membrane led to the reduction of effective permeation area. Microphotograph analysis results for the membrane after permeation test confirmedthe diffusion of Pyrex glass seal into the membrane.

• Journal of the Korea institute for structural maintenance and inspection
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• v.15 no.4
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• pp.165-174
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• 2011

This research aims at the optimal constitution of sensors required to identify the structural shortcoming of roller-coaster. In this research we analyzed the dynamic characteristics of roller-coaster by three dimensional FE modelling, decided on the appropriate location and number of sensors through optimal transducer theory, abstracted the mathematical value of modal features before and after damage on the basis of optimally placed and numbered sensors. and then presented it as a primary information about the basic structure which would be applied to damage estimation. As a target structure, the roller-coater at Seoul Children's Grand Park was chosen and built as a model reduced by one twentieth in size. In order to consider the Kinetics features particular to the roller-coaster structure, we made an exact three-dimensional FE modelling for the model structure by means of Spline function. As for the proper location and number of sensors, it was done by applying EIM and EOT. We also estimated the damage from the combination of strength, flexibility, and model corelation after abstracting the value of modal features. Finally the optimal transducer theory presented here in this research was proved to be valid, and the structural damage was well identified through changes in strength and flexibility. As a result, we were able to present the optimal constitution of sensors needed for the analysis of dynamic characteristics and the development of techniques in dynamic characteristics, which would ultimately contribute to the development of health monitoring for roller-coaster.

• Journal of the Korean Magnetics Society
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• v.24 no.4
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• pp.101-106
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• 2014

The glass/Ta(5.8 nm)/NiFe(5 nm)/Cu(2.3 nm)/NiFe(3 nm)/IrMn(12 nm)/Ta(5.8 nm) GMR-SV (giantmagneto-resistance-spin valve) multilayer structure films with a magnetoresistance ratio (MR) of 5.0 % and a magnetic sensitivity (MS) of 1.5%/Oe was deposited by dc magnetron sputtering method. Also, GMR-SV device having a width of $7{\mu}m{\sim}8{\mu}m$ similar to the diameter of RBC (red blood cell) was fabricated by the light lithography process. When RBCs coupled with several magnetic beads with a diameter of $1{\mu}m$ dropped upon the GMR-SV device having MR = 1.06% and MS = 0.3 %/Oe, there is observed the variation of about included of a resistance value of ${\Delta}R=0.4{\Omega}$ and ${\Delta}MR=0.15%$ around a external magnetic field of -0.6 Oe. From these results, the GMR-SV device having the width magnitude of a few micron size can be applied as the biosensor for the analysis of a new magnetic property of hemoglobin inside of RBC combined to magnetic beads.

• Journal of the Korea Concrete Institute
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• v.25 no.2
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• pp.209-215
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• 2013

This study is aimed to identify the method to use the CaO-$Al_2O_3$ system of rapidly cooled steel making slag (RCSS) as the environment-friendly inorganic accelerating agent by analyzing its physical and chemical properties. The fraction of rapidly cooled steel making slag is distinguished from its fibrous, and the contents of CaO and $Fe_2O_3$ are inversely proportional across different fractions. In addition, as the content of CaO decreased and the content of $Fe_2O_3$ increased, the loss ignition tended to become negative (-) and the density increased. The pore distribution by mercury intrusion porosimetry is very low as compared to the slowly cooled steel-making slag, which indicates that the internal defect and the microspore rate are remarkably lowered by the rapid cooling. To analyze the major minerals the rapidly cooled steel-making slag, XRD, f-CaO quantification and SEM-EDAX analysis have been performed. The results shows that f-CaO does not exist, and the components are mainly consisted of $C_{12}A_7$ and reactive ${\beta}-C_2S$.