• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 한국전기전자재료학회 2009년도 춘계학술대회 논문집
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• pp.7-8
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• 2009

Non-contact critical current measurement apparatus was developed using hall probe which measures the magnetic field distribution across the width of superconducting tape. The hall probe consists of 7 independent hall sensors which lie in a line 600 ${\mu}m$. The difference between maximum and minimum magnetic field in the magnetic filed distribution is a main parameter to determine the critical current. As preliminary research, we calculated the magnetic field intensity at the middle sensor, which is a minimum magnetic field and generated by the circular shielding current modeled by Bean model. We confirmed that there are some parameters that affect on the minimum magnetic field; the distance between superconducting layer and hall sensor, the width of superconducting tape, and the critical current distribution across the width of superconducting tape. Among these parameters, the distance between superconducting layer and hall sensor highly influences on the minimum magnetic field.

• Proceedings of the KIEE Conference
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• 대한전기학회 1998년도 하계학술대회 논문집 A
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• pp.125-127
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• 1998

Superconducting tape is being developed for electrical equipment such as superconducting transformers and generators. AC loss reduction is primary concern in the development of such high-efficiency equipment. AC losses in Bi-2223 silver-sheathed tapes, both single and multi-filamentary, were investigated by means of AC magnetization techniques. The results were compared with the hysteresis loss equation based on Bean model and the eddy current loss equation. The AC loss, of the mono-filamentary tape was the hysteresis. On the contrary, the AC loss of the multi-filamentary tape was substantially dominated by the eddy current loss in the Ag matrix.

• Proceedings of the KIEE Conference
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• 대한전기학회 1998년도 추계학술대회 논문집 학회본부 B
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• pp.702-705
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• 1998

To be applied to electrical equipment HTSC tapes have to endure external stress and so on. The critical current density has been shown depending on the mechanical properties, strain and bending stress. AC loss reduction is primary concern in the development of such high-efficiency equipment. AC losses in Bi-2223 silver-sheathed tapes, both single and multi-filamentary, were investigated by means of AC magnetization techniques. The results were compared with the hysteresis loss equation based on Bean model and the eddy current loss equation. The AC loss of the mono-filamentary tape was the hysteresis. On the contrary, the AC loss of the multi-filamentary tape was substantially dominated by the eddy current loss in the Ag matrix.

• Korean Journal of Occupational Health Nursing
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• 제22권4호
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• pp.343-351
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• 2013

Purpose: This study was to identify factors affecting mammography screening behavior in job women by attitude, social influence and self-efficacy model. Methods: The data were obtained from 171 job women in one residency area by structural questionnaire from March to June 2013 and analysed by using $x^2$-test, ANOVA, Spearman's correlation and logistic regression analysis. Results: The each performance rate was 45.1% in mammography, 44.9% in breast self examination and 48.5% in physical examination. The mammography performance rate in job women showed higher significance in the groups of 1) older age, urban residency, marital status or high economic state, 2) shorter office hours or higher job position, 3) childbirth experience or menopause and 4) preferring soy bean food, practicing regular exercise, suffering chronic disease or receiving radiation therapy. Attitude, social influences and self-efficacy made significant differences in mammography performance. Logistic regression analysis showed that 50 years or older, urban residency, social influences towards mammography and high self-efficacy were significant relationship. Conclusion: In order to increase the mammography performance rate, the intervention strategies are needed to increase positive social influences or self-efficacy and to offer public information to younger age.

• Proceedings of the KIEE Conference
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• 대한전기학회 1998년도 추계학술대회 논문집 학회본부A
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• pp.382-385
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• 1998

To be applied to electrical equipment HTSC tapes have to endure external stress and so on. The critical current density has been shown depending on the mechanical properties, strain and bending stress. AC loss reduction is primary concern in the development of such high-efficiency equipment. AC losses in Bi-2223 silver-sheathed tapes, both single and multi-filamentary, were investigated by means of AC magnetization techniques. The results were compared with the hysteresis loss equation based on Bean model and the eddy current loss equation. The AC loss of the mono-filamentary tape was the hysteresis. On the contrary, the AC loss of the multi-filamentary tape was substantially dominated by the eddy current loss in the Ag matrix.

• Bulletin of the Korean Chemical Society
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• 제11권6호
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• pp.560-563
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• 1990

A.c. susceptibility for $Bi_{1.4}Pb_{0.6}Sr_2Ca_2Cu_{3.6}O_x$ superconductor is measured as a function of temperature at different value of a.c. magnetic field amplitude. Two transition steps are attributed to the intergranular and intragranular properties. Based on Bean's critical state model, intergranular critical current density, $J_c^{gb}$ (11 $A/cm^2$ at 77 K) and intragranular critical current density, $J_c^g (7{\times}10^3\;A/cm^2$ at 100 K) are estimated. The low values of $J_c^{gb}$and $J_c^g$ reflect a poor nature of coupling between grains and the low pinning force density of intragrain in $Bi_{1.4}Pb_{0.6}Sr_2Ca_2Cu_{3.6}O_x$ superconductor.

• Journal of Magnetics
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• 제16권1호
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• pp.15-18
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• 2011

We have studied the $TiO_2$ doping effects on the flux pinning behavior of an $MgB_2$ superconductor synthesized by the in-situ solid-state reaction. From the field-cooled and zero-field-cooled temperature dependences of magnetization, the reversible-irreversible transition of $TiO_2$-doped $MgB_2$ was determined in the H-T diagram (the temperature dependence of upper critical magnetic field and irreversibility line). For comparison, the similar measurements are also obtained from SiC-doped $MgB_2$. The critical current density was estimated from the width of hysteresis loops in the framework of Bean's model at different temperatures. The obtained results manifest that nano-scale $TiO_2$ inclusions served as effective pinning centers and lead to the enhanced upper critical field and critical current density. It was concluded that the grain boundary pinning mechanism was realized in a $TiO_2$-doped $MgB_2$ superconductor.

• Progress in Superconductivity and Cryogenics
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• 제23권1호
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• pp.12-16
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• 2021

The magnetic properties of heat treated O-series high temperature superconducting (HTS) GdBCO coated conductor (CC) tapes which were formed of Ag/GdBCO/Buffer-layers/Stainless Steel (SS), were investigated by employing a Quantum Design PPMS-14. Using a modified Bean model, the critical current density J_c values have been estimated from the 𝚫m_irr(H) data, which are obtained by measuring the magnetic moment m(H) loops. For a range of intermediate fields, which are interacting or collective flux pinning area, the magnetic flux behaviors were investigated from the relationship J_c ∝ H^-β. In addition, the changes of irreversibility magnetic field H_irr line of heat-treated O-series HTS GdBCO CC tapes were analyzed, according as the annealing temperature under oxygen flowing increases. Both weak and strong break-downs were found by examining the changes of irreversibility magnetic field H_irr lines.

• Journal of Korean Ophthalmic Optics Society
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• 제18권1호
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• pp.61-65
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• 2013

Purpose: This study was performed to identify the relations between glaucoma and dietary patterns in Korean adults, aged 30 years or older. Methods: 6,453 subjects (male 2,759, female 3,694 subjects) who aged 30 years or older from the Korea National Health and Nutrition Examination Survey were included. Glaucoma was assessed based on the subjects were diagnosed by a doctor. At first, waist circumference and body mass index (BMI) were compared to investigate the association between glaucoma and obesity index. Secondly, dietary patterns using factor analysis for external blue colored fish(mackerel), seaweed(seaweed, laver), bean(bean, soybean milk), vegetables(sprout, spin, carrot, cabbage, cucumber, pepper, tomato, pumpkin) and fruits(tangerine, apple, pear, strawberry, grape, peach) were obtained. Lastly, regression analysis was used for glaucoma and emerged dietary factors. Results: In glaucoma and normal group, waist circumference and BMI were $82.25{\pm}9.96cm$ and $23.27{\pm}2.84kg/m^2$, $75.79{\pm}13.79cm$ and $22.39{\pm}4.06kg/m^2$, respectively. There was statistically significant difference (p<0.05). Three dietary patterns were emerged from the factor analysis, and factor 1 was included sprout, spin, carrot, cabbage, seaweed, cucumber, mackerel, laver. The factor 1 of dietary pattern was inversely related to the prevalence of glaucoma (OR: 0.697, 95%CI: 0.496-0.980, p=0.038), and model adjusting for age and sex was showed the same trend (OR: 0.698, 95%CI: 0.497-0.982, p=0.039). Conclusions: This study was analysed first with glaucoma and dietary pattern in Korean, and vegetables, laver and mackerel significant associated to reduce the risk of glaucoma.

• Journal of the Korean Society of Food Science and Nutrition
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• 제38권9호
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• pp.1253-1257
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• 2009

The effects of seven commercial gums (xanthan gum, guar gum, pectin, gum arabic, gellan, locust bean gum, and sodium alginate) at different concentrations (0, 0.3, and 0.6%) on flow properties of sweet potato starch (SPS) pastes were investigated. Flow behavior characteristics were adequately described by power law flow model, and yield stress was also measured by vane method. SPS-gum mixtures (5% w/w) at $25^{\circ}C$ were found to have high shear-thinning flow behavior with yield stress, and their consistency index (K) and apparent viscosity ($\eta_{a,100}$) increased with elevated gum concentration, except for pectin and sodium alginate. Vane yield stress ($\sigma_o$) value of SPS-pectin mixture was lower when compared to other mixtures while that of SPS-gellan mixture was much higher. Most of the gums, except for pectin, gum arabic, and sodium alginate, showed a synergistic effect on the elastic properties of SPS-gum mixtures. In general, the flow properties of SPS-gum mixtures appeared to be strongly influenced by the addition of gum, and dependent on the type and concentration of gum.