• Nutritional Sciences
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• v.1 no.1
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• pp.29-33
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• 1998

The present study was designed to compare the nutrient intake and iron status of athletic female students majoring in aerobics (n=18) to those of age-matched(20-22 yr) sedentary controls (n=19). The athletic students were exercising regularly for 9.1$\pm$1.4 hrs/wk and the mean training period of aerobics was 2.9$\pm$0.2 years. Means of height, weight, and body mass index calculated as the Quetlet index were similar between athletic and sedentary students. However, mean body fat % of the athletic students (22.3$\pm$1.0%) was significantly lower than that of the sedentary controls (25.8$\pm$0.6%), indicating the effects of routine exercise. Mean daily iron intake was not significantly different between groups (9.9$\pm$0.7 mg vs. 10.9$\pm$0.8 mg), but much lower than the Korean RDA (18 mg/d) in both groups. Dietary calcium intake of the athletic students was significantly lower than that of the sedentary controls. Hematocrit (Hct) and hemoglobin (Hb) values were significantly lower in the athletic students than in the sedentary students (Hct : 40.0$\pm$0.7% vs. 43.8$\pm$0.5% ; Hb : 12.6$\pm$0.3g/dl vs. 14.8$\pm$0.3 g/dl). However, other iron status values such as serum iron, TIBC, and transferrin saturation were not significantly different between groups. Therefore, the low hemoglobin levels in the athletic group are probably due to plasma dilution in endurance-trained individuals. Serum ferritin level was a little lower in the athletic group, but no significant difference between groups was found. Serum triglyceride concentration in the athletic students was significantly lower than that in the control students. In conclusion the findings suggest that regular training of female athletes majoring in aerobics is associated with an increased risk of pseudoanemia due to plasma volume expansion and a decreased risk of coronary heart disease by decreasing body fat and blood lipid level.

• Korean Journal of Community Nutrition
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• v.5 no.2
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• pp.243-252
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• 2000

This study examined the effects of excess intake of calcium(Ca) and iron(Fe) supplements on iron bioavailability, liver and kidney functions in anemic model rats. Seven-week-old female rats were first fed and Fe-deficient diet for ten weeks, and then fed one of nine experimental diets for an additional eight weeks, containing three levels of Ca, normal (0.5%) or high(1.5%) or excess (2.5%) and three levels of Fe, normal(35ppm) or high(210 ppm) or excess(350ppm). In anemic model rats, serum Fe, total iron binding capacity(TIBC), hemogolin(Hb), hematocrit(Hct) and liver Fe contents were significantly decreased. Apparent Fe absorption significantly increased with increasing dietary Fe levels, and decreased with increasing dietary Ca levels. serum Fe concentration significantly increased in rats fed a high- and excess-Fe diet, and decreased in rats fed a excess-Ca diet. TIBC was decreawed in rats fed a excess-Ca diet, and transferrin saturation(%) increased in rats fed ahigh- and excess-Fe diet. Hb and Hct were decreased in rats fed an excess-Ca diet regardless of dietary Fe levels. Fe and thiobarbituric acid reactin gsubstance(TBARS) Contents of liver significantly increased in rats fed a high- and excess0-Fe diet, and decreased in rats fed a high- and excess-Ca diet. Fe content of the spleen showed similar results. Urinary creatinine and GFR increased in rats fed an excess-Ca diet regardless of dietary Fe levels. GOT, GPT and LDH were not significantly affected by dietary Ca and Fe levels. These results suggest that excess intake of Fe may increase liver Fe deposits and TBARS, and excess intake of Ca may decrease Fe bioavailability and kidney function leading to potential health problems in anemic model rats.

• Resources Recycling
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• v.7 no.4
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• pp.43-49
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• 1998

We investigated the effects of the powder characteristics of various domestic iron oxides (${\alpha}Fe_2O_3$) on the magnetic properties of Sr-ferrites The particle size and the distribution of iron oxides were classified hy three different rerinning methods, and greatly a affected on the magn$\xi$tic prope$\pi$ies and the mmphology of Sr-ferntes. The agglomeration of Ruthner iron oxides and the large particles of Chemirite (CY) above $0.80{\mu}\textrm{m}$ were degraded the prope며es of Sr-fcrrites. The optimal magnetic prope$\pi$ies of Srt territes, showing 68.2 emu/g of saturation magnetization and 4300 Oe of intrinsic coerClvity, were achieved at the following c conditions; Chemirite (P2EP) iron oxides of $0.14{\mu}\textrm{m}$ molar ratio of 5.8. and calcination of $1150^{\circ}C$/1 hr.

• Korean Journal of Community Nutrition
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• v.8 no.1
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• pp.26-32
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• 2003

This study was designed to assess the nutritional iron status and anemia of middle school girls. Three-hundred-fifty- three female subjects in Ulsan metropolitan city were evaluated using a questionnaire, and hematological indices. The average height and weight of the respondents were 157.19 $\pm$ 5.57 cm and 51.06 $\pm$ 9.42 kg respectively. The average Body Mass Index (BMI, $kg/m^2$) was 20.63 $\pm$ 3.23, which was within the normal range. With regard to clinical symptoms, the greatest number of respondents reported that they experienced 'decreased ability to concentrate'. The total caloric intake of each subject was 1743.28 $\pm$ 343.47 kcal(83.01% of the Korean RDA) and the calcium intake was 634.98 $\pm$ 201.43 mg (79.37% of the Korean RDh) . The mean daily intake of iron was 14.76 : 4.36 mg (92.25% of the Korean RDh) and the heme iron intake was 6.12 $\pm$ 2.30 mg, which was 41.5% of the total iron intake. The average hemoglobin (Hb) concentration of the subjects was 13.24 $\pm$ 1.01 g/dl, and the average hematocrit (Hct) level was 37.79 $\pm$ 4.10%. The transferrin saturation {TS (%)} was 19.41 $\pm$ 9.21%, and the ferritin level was 26.26 $\pm$ 18.60 ng/ml. The iron deficiency anemia among the subjects was estimated at 6.1% by using Hb (< 12 g/ml), 20.5% by using Hct (< 36%), 30.8% by using 75 (< 14%) , and 23.1% by using ferritin (< 12 ng/ml) The total iron binding capacity (TIBC) showed a negative correlation with the Hb, iron, ferritin and 75. With regard to the correlation between blood biochemistry and clinical symptoms related to anemia, the Hb concentration was negatively correlated with 'pale face'(p < 0.05) . In addition, the level of iron was significantly and negatively correlated with 'poor memory' (p<0.01) and the ferritin concentration was negatively correlated with 'no appetite '(p < 0.05) ,'pale face (p < 0.05) . These results suggest that the prevalence of iron deficiency among middle school girls is very high; therefore, guidelines on dietary support and nutritional education to improve their dietary iron status should be provided.

• Journal of Magnetics
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• v.1 no.1
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• pp.51-54
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• 1996

The effects of additional P-doping on the magnetic properties, thermal stability and cation distribution of Co-doped ${\gamma}-{Fe_2} {O_3}$have been investigated by means of magnetic annealing and measurements with vibration sample magnetometer and torque magnetometer. It is found that the P-doping promotes the coercivity and its magnetic-thermal stability, which may be attributed to increase of the cubic magneto-crystalline anisotropy constant, $K_1$ and the activation energy, E, for cation rearrangement, respectively. The cation distribution of P and Co-substituted iron oxide was calculated from the variation of the saturation magnetization with P-doping on the basis of the Neel model. It was found that the most of P ions in the iron oxides occupied the B-site of spinel lattice.

• Journal of Magnetics
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• v.22 no.2
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• pp.196-202
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• 2017

The occurrence of ferroresonance in electrical systems including nonlinear inductors such as transformers will bring a lot of malicious damages. The intense ferromagnetic saturation of the iron core is the most influential factor in ferroresonance that makes nonsinusoidal current and voltage. So the nonlinear behavior modeling of the magnetic core is the most important challenge in the study of ferroresonance. In this paper, the ferroresonance phenomenon is investigated in a single phase transformer using the finite element method and considering the hysteresis loop. Jiles-Atherton (JA) inverse vector model is used for modeling the hysteresis loop, which provides the accurate nonlinear model of the transformer core. The steady-state analysis of ferroresonance is done while considering different capacitors in series with the no-load transformer. The accurate results from copper losses and iron losses are extracted as the most important specifications of transformers. The validity of the simulation results is confirmed by the corresponding experimental measurements.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2006.05a
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• pp.493-495
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• 2006

The hysteresis characteristics of flux-lock reactor, which is an essential component of flux-lock type superconducting fault current limiter (SFCL), was investigated. The hysteresis loss of iron core in flux-lock type SFCL does not happen due to its winding's structure especially in the normal state. From the equivalent circuit for the flux-lock type SFCL and the fault current limiting experiments, the hysteresis curves could be drawn. Through the hysteresis curves together with the fault current level due to the inductance ratio for the 1st and 2nd windings, the increase of the number of turns in the 2nd winding of the flux-lock type SFCL had a role to prevent the iron core from saturation.

• Proceedings of the KIEE Conference
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• 1993.07b
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• pp.965-967
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• 1993

In this paper, Take two perment magnets and three iron bars and wind copper wire around one or the bars. This paper demonstrate that the method or calculation yields the right results with MAXWELL-2D program package for computing magnetic field, also indicate the value to which the current in the coil has to be limited to prevent saturation of the iron or the cores. The Finally procedures for design of LDM are discussed.

• Proceedings of the PSK Conference
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• 2003.10b
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• pp.117.2-117.2
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• 2003

The mechanism by which lead enters glial cells was examined. The uptake of lead reached saturation when assays were performed in buffers at pH 5.5 and 7.4. The Vmax and Km was 2.7 pmoles/mg protein/min and 13.4 M in the buffer at pH 7.4, respectively, whereas the Vmax and Km was 329 fmoles/mg and 8.2 M in the buffer at pH 5.5, respectively. Uptake in a buffer at pH 5.5 but not at pH 7.4 was inhibited by iron. Cells treated with the iron chelator desferoxamine displayed higher levels of the divalent metal transporter mRNA and protein. (omitted)

• Korean Journal of Community Nutrition
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• v.6 no.1
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• pp.28-35
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• 2001

This study was designed to assess the iron nutritional status and anemia of high school students. 383 female subjects in Ulsan Metropolitan city were evaluated using a questionnaire, and a measurement of hematological indices. The average height and weight of the respondents were 161.24$\pm$4.90 cm and 53.12$\pm$6.37kg, repectively. The average BMI(body mass index) was 20.43$\pm$2.26 which was in the normal ramge. The average hemoglobin(Hb) concentration of the subjects was 13.14$\pm$0.97g/dl, and the average hematocrit(Hct) level was 40.84$\pm$17.40%. Transferrin saturation{TS(%)} was 20.86$\pm$10.32%, and the ferritin by Hct(＜36%), 27.2%by TS(＜14%),26.6% by ferritin(＜12 ng/ml). As for clinical symptoms, the greatest number of respondents reported that they experienced ‘decreased ability to concectrate’. Mean daily intakes of iron were 14.89$\pm$4.48 mg and heme iron intakes were 5.04$\pm$2.13 mg, which was 29.6% of total iron intake. The total iron binding capacity(TIBC) was negatively correlated with Hb concentration(r= -0.222, p＜0.01). Serum ferritin was positively correlated with Hb concentration(r= - 0.323, p＜0.05) and negatively correlated with TIBC(r= -0.367, p＜0.01). TS(%) was positively correlated with Hb concentration(r= 0.402, p＜0.01) and positively correlated with serum ferritin(r=0.413, p＜0.01). As for the correlation between blood biochemistry and clinical symptoms related to anemia, the Hb concentration was negatively correlated with ‘shortening of breath when going upstairs(p＞0.05)’ and ‘cold hands and feet’ significantly(r= -0.109, p＜0.05). The level of Mean corpuscular volume(MCV) was negatively correlated with ‘feel dizzy when standing up’,‘tired out easily’, and ‘decrease ability to concentrate’ significantly(p＜0.05). In particular, the level of Fe was negatively correlated with ‘shortening of breath when going upstairs’ and ‘feeling blue’ significantly(p＜0.01). These results suggest That the prevalence of iron deficiency of female high school students is very high, therefore guidelines for diet supports and nutrition education to improve their iron status should be provided.