• Journal of Nutrition and Health
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• v.32 no.8
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• pp.946-956
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• 1999

The iron nutritional status of 328(20-70 years old) women in Seoul and Puyo areas was evaluated using a dietary information and a measurement of hematological indices. The serum iron was measured by Red Blood Cell(RBC), Hemoglobin(Hb), Hematocrit(Hct), Serum Iron(S-Fe), Total Iron Binding Capacity (TIBC), Transferrin Saturation(TS) and Serum Ferritin(SF) and was analyzed with the information obtained by interviews which included socio-demographic variables and the dietary pattern of the subjects. The mean Hb was 12.6 $\pm$ 1.21g/dl(Seoul : 12.4 $\pm$ 1.14g/dl, Puyo : 13.2 $\pm$ 1.28g/dl), Hct was 38.7 $\pm$ 3.84%(Seoul: 37.5 $\pm$ 3.28%, Puyo: 4.19 $\pm$ 3.48%), S-Fe was 76.8 $\pm$ 31.49ug/dl(Seoul: 68.8 $\pm$ 27.3ug/dl, Puyo: 78.8 $\pm$ 32.3ug/dl) and TIBC was 277.7 $\pm$ 86.15ug/dl(Seoul: 354.1 $\pm$ 129.8ug/dl, Puyo: 259.0 $\pm$ 59.55ug/dl). The mean Ts(%) was 30.9 $\pm$ 17.9% (Seoul: 21.7 $\pm$ 10.52%, Puyo: 33.2 $\pm$ 18.68%) and the level was significantly higher in Puyo women(p<0.05). The mean SF was 45.4 $\pm$ 46.21ng/ml(Seoul: 53.6 $\pm$ 50.21ng/ml, Puyo: 36.1 $\pm$ 39.83ng/ml). The Red Blood Cell(RBC) showed a negative correlation with age and Hb, Hct showed a negative correlation with education and income level. However TIBC showed a and total energy expenditure per day. Energy, protein, carbohydrate, iron and vit.C intake showed a positive correlation with Hb and Hct. In particular, heme iron showed a positive correlation with RBC and nonheme iron of Hb, income level and iron intake affected on the level of Hct. In Seoul women, the age of menarche affected on the level of TIBC, total energy expenditure affected on the level of Hct. In Seoul women, the age of menarche affected on the level of TIBC, total energy expenditure affected on the level of S-Fe.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.29 no.1
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• pp.42-49
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• 2019

Objective: Chronic obstructive pulmonary disease(COPD) is characterized by persistent airflow limitations associated with chronic inflammatory response due to noxious particles or gases in the lung. Iron deficiency is associated with chronic inflammation, such as COPD. The aim of this study was to evaluate the relationship among iron deficiency, iron homeostasis, and inflammation in retired miners with COPD. Methods: The serum levels of ferritin, soluble transferrin receptor(sTfR), and transferrin saturation(TSat) as biomarkers for iron deficiency and high-sensitivity C-reactive protein(hsCRP) as a biomarker for inflammation and hepcidin as a biomarker for iron homeostasis were measured in 93 male subjects. Iron deficiency was defined as any one or more of (1) sTfR>28.1 nmol/L, (2) TSat<16%, and (3) ferritin< $12{\mu}g/L$. Results: Iron deficiency was found 28% of the study subjects. Median levels of serum hsCRP was significantly increased related to airflow limitation of COPD(GOLD 1, $0.09{\mu}g/dL$ vs. GOLD 2, $0.17{\mu}g/dL$ vs. GOLD $3{\leq}$, $0.30{\mu}g/dL$, p=0.010), and was positively correlated with hepcidin(p=0.009). Mean level of serum hepcidin was lower in COPD subjects with iron deficiency(p=0.004) and serum levels of hepcidin was negatively correlated with %$FEV_1$ predicted(p=0.030). Conclusions: These results suggest that high serum levels of hepcidin are related to severe airflow limitation or inflammation and can decrease iron availability, regardless of iron status.

• Resources Recycling
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• v.10 no.3
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• pp.23-28
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• 2001

Zinc ion could be recovered from metal plating wastewater with the spent iron oxide catalyst which was used in the plant of Styrene Monomer(SM) production. The zinc was recovered more than 98.7% at higher than pH 2.0. The saturation magnetization of the spent catalyst is enough high as 59.4 emu/g to apply in the solid-liquid separation after treating the wastewater. The mechanism of zinc recovery with the iron oxide catalyst could be a electro-chemical adsorption at pH 3.0~8.5, and a precipitation as $Zn(OH)_2$ at higher than pH 8.5.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.19 no.2
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• pp.66-69
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• 2009

The compositional dependence of bismuth iron oxides and effect of La-substitutions in the structure of $BiFeO_3$ compounds were investigated, which compounds were synthesized by conventional ceramic processing. It is shown that some of bismuth iron oxides including $BiFeO_3$ show the narrow single phase region. The effect of La-doping in $BiFeO_3$ was presented as disappearance of many impurity phases of Bi-Fe-O compounds. The lower electrical resistivity was obtained as those compositions of Fe deficient region and La-doped $BiFeO_3$. The saturation magnetization of La-doped $BiFeO_3$ was increased with La content. The dielectric dispersion was also observed for those Bi-Fe-O compounds with Fe deficient and La-doped $BiFeO_3$ at low frequencies under 1 kHz.

• Journal of Powder Materials
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• v.26 no.6
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• pp.481-486
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• 2019

Iron oxides currently attract considerable attention due to their potential applications in the fields of lithiumion batteries, bio-medical sensors, and hyperthermia therapy materials. Magnetite (Fe₃O₄) is a particularly interesting research target due to its low cost, good biocompatibility, outstanding stability in physiological conditions. Hydrothermal synthesis is one of several liquid-phase synthesis methods with water or an aqueous solution under high pressure and high temperature. This paper reports the growth of magnetic Fe₃O₄ particles from iron powder (spherical, <10 ㎛) through an alkaline hydrothermal process under the following conditions: (1) Different KOH molar concentrations and (2) different synthesis time for each KOH molar concentrations. The optimal condition for the synthesis of Fe₃O₄ using Fe powders is hydrothermal oxidation with 6.25 M KOH for 48 h, resulting in 89.2 emu/g of saturation magnetization at room temperature. The structure and morphologies of the synthesized particles are characterized by X-ray diffraction (XRD, 2θ = 20°-80°) with Cu-kα radiation and field emission scanning electron microscopy (FE-SEM), respectively. The magnetic properties of magnetite samples are investigated using a vibrating sample magnetometer (VSM). The role of KOH in the formation of magnetite octahedron is observed.

• Bulletin of the Korean Chemical Society
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• v.28 no.12
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• pp.2279-2282
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• 2007

Highly crystalline, uniform Fe nanoparticles were successfully synthesized and encapsulated in zirconia shell using sol-gel process. Two different approaches have been employed for the coating of Fe nanoparticle with zirconia. The thickness of zirconia shell can be readily controlled by altering molar ratio of Fe nanoparticle core to zirconia precursor in the first case where as reaction time was found to be most effective parameter to controlled the shell thickness in the second method. The structure and magnetic properties of the ZrO2-coated Fe nanoparticles were studied. TEM and HRTEM images show a typical core/shell structure in which spherical α-iron crystal sized of ~25 nm is surrounded by amorphous ZrO2 coating layer. TGA study showed an evidence of weight loss of less than 2% over the temperature range of 50-500 °C. The nanoparticles are basically in ferromagnetic state and their magnetic properties depend strongly on annealing temperature. The thermal treatment carried out in as-prepared sample resulted in reduction of coercivity and an increase in saturation magnetization. X-ray diffraction experiments on the samples after annealing at 400-600 °C indicate that the size of the Fe@ZrO2 particles is increased slightly with increasing annealing temperature, indicating the ZrO2 coating layer is effective to interrupt growing of iron particle according to heat treatment.

• Journal of Powder Materials
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• v.14 no.1 s.60
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• pp.19-25
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• 2007

This study was focused on the optimization of low-pressure ultrasonic spraying process for synthesis of pure ${\gamma}-Fe_2O_3$ nanoparticles. As process variables, pressure in the reactor, precursor concentration, and reaction temperature were changed in order to control the chemical and microstructural properties of iron oxide nanoparticles including crystal phase, mean particle size and particle size distribution. X-ray diffraction (XRD) and transmission electron microscopy (TEM) studies revealed that pure ${\gamma}-Fe_2O_3$ nanoparticles with narrow particle size distribution of 5-15 nm were successfully synthesized from iron pentacarbonyl ($Fe(CO)_{5}$) in hexane under 30 mbar with precursor concentrations of 0.1M and 0.2M, at temperatures over $800^{\circ}C$. Also magnetic properties, coercivity ($H_c$) and saturation magnetization ($M_s$) were reported in terms of the microstructure of particles based on the results from vibration sampling magnetometer (VSM).

• Korean Journal of Community Nutrition
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• v.8 no.5
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• pp.726-735
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• 2003

In this study, anthropometric and biochemical indicators and related factors for community dwelling elderly living alone (ELA). as well as for elderly not living alone (ENLA) were explored. The subjects were 140 elderly females (70 living alone, 70 not living alone) residing in Bucheon. Anthropometric measurements revealed significant differences between the two groups (ELA/ENLA) for height, weight, BMI, triceps skinfold thickness, suprailiac skinfold thickness, subscapular skinfold thickness, and body fat percentage. The ELA showed significantly lower data for most of the anthropometric indices, except PIBW. Biochemical indicators of iron status (hemoglobin, serum iron, transferrin saturation) were significantly lower for the ELA, whereas the total serum cholesterol, LDL-C, LDL-C/HDL-C, for the ELA were significantly higher. The prevalence of hypercholesterolemia (240 mg%) was 30%. The latter three are not in accordance with general malnutrition among the ELA. The hemoglobin of the ELA was positively correlated with energy, fat, iron and cholesterol intake, but negatively correlated with height. The serum cholesterol of the ELA was Positively associated with most of their nutrient intake.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.35 no.12
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• pp.567-572
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• 1986

In this paper, a new type of step motor with two degree of mechanical freedom, which is named rotary-Linear Step Motor(RLSM), is presented. Its rotor axis can perform linear and rotary motions either separately or simultaneously. This paper discribes the design of RLSM using finite element method in which the magnetic saturation effect of the iron core is taken into account. The design parameters such as torques, forces and inductances are obtained from the computed magnetic vector potentials. A new type of Rotary-Linear Step Motor was constructed. The calculated parameters agree well with measurements.

• 전기의세계
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• v.29 no.1
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• pp.58-64
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• 1980

In this paper, this objective is to obtain the mathematical model which describes the dynamic characteristics of variable reluctance(VR) step motor, the most important and most widely used motor in practice. In the development of the mathematical model for VR step motor, first the general nonlinear dynamic equations which describe the N-phase VR step motor are derived. These general equations are then applied to the multiple-step type of VR step motor in case, for simplicity, maynetic saturation and core lossess in the iron are neglected. These nonlinear dynamic equations are numerically analysed by the computer simulation, through which the performance characteristics of a step motor undertest are investigated under the various operating conditions.