• Progress in Superconductivity and Cryogenics
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• v.17 no.3
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• pp.1-4
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• 2015

Production of $MgB_2$ film on metallic Hastelloy with SiC as the buffer layer was achieved by means of hybrid physical-chemical vapor deposition technique, whereas SiC buffer layers with varied thickness of 170 and 250 nm were fabricated inside a pulsed laser deposition chamber. Superconducting transition temperature and critical current density were verified by transport and magnetic measurement, respectively. With SiC buffer layer, the reduced delaminated area at the interface of $MgB_2$-Hastelloy and the slightly increased $T_c$ of $MgB_2$ tapes were clearly noticed. It was found that the upper critical field, the irreversibility field and the critical current density were reduced when $MgB_2$ tapes were buffered with SiC buffer layer. Clarifying the mechanism of SiC buffer layer in $MgB_2$ tape in affecting the superconducting properties is considerably important for practical applications.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.53 no.12
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• pp.732-738
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• 2004

In this paper, we constructed 13 turns pancake coil and solenoid coil with HTS tape and measured AC losses of the pancake coil. The critical current of the pancake coil and the solenoid coil were 80A and 109A, respectively. To compare measured AC losses of the two coils, we carried out numerical analysis using 2-D FEM program for manufactured coils. This paper presents current density distribution, flux density distribution and AC losses of the pancake coil and the solenoid. As a result, we obtained that current density distribution was closely related to the orientation of magnetic field and distribution of AC losses were also closely related to the perpendicular component of flux density distribution in coil. The calculated AC losses of the two coils showed good agreement with measured AC losses and AC losses of the pancake coil was about 9 times bigger than that of the solenoid coil under the same turns and length.

• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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• v.19 no.2
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• pp.1-9
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• 2013

Background: The purpose of this study is to analysis of correlation upper body according to forward head posture. Methods: The subjects of this study were 40 female university students who were equally and randomly allocated to a forward head posture group, normal group. Using general posture system, electromyograph, visual analogue scale, tape measurement, neck disability index were evaluated. Results: There was positive correlation between posture analysis and Sternocleidomastoid, neck flexion (p<.05). There was positive correlation between Craniovertebral angle (CVA) and trapezius upper, VAS (p<.05). There was negative correlation between posture analysis and CVA (p<.05). There was negative correlation between Cranial rotation angle and CVA (p<.05). Conclusion: Increased forward head posture lead to increase of pain, muscles activity, so it suggests to be necessary on the prevention of dysfunction and limited activities daily living.

• Physical Therapy Korea
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• v.3 no.2
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• pp.36-41
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• 1996

The purpose of this study was to determine whether the biomechanical variables of the walking patterns of the obese children compared with those of normal children would revealing significant differences. Normal(N=25) and obese(N=19) subjects were screened based on a health record which was examined to eliminate any subjects who had any pathological condition related to their gait. Data for a minimum of 5 repeated walking trials were collected using a stop watch and a tape measure. Basic kinematic analyses yielded data based on the following variables : stride length divided by leg length, and cadence divided by leg length. This measurement data was classified by the Obesity Index calculated from by height, weight data. Results showed no significant difference among normal, obese and subjects(p>.05). Difficulties in formulating the experimental condition and poor equipment quality are thought to be reason for the inconclusive results. Future studies might include medical complications such as tibia vara, genu valgum, other diseases caused by obesity.

• Journal of Korean Biological Nursing Science
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• v.17 no.3
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• pp.271-276
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• 2015

Purpose: This study was to evaluate the effects on the heart rate and respiration rate of preterm infants when providing auditory stimulation on them. Methods: The design of this study was a nonequivalent control group pretest-posttest design in a quasi experimental study. Forty preterm infants were assigned to experimental and control groups : 20 in the auditory and 20 in the control group. The data were collected from May 2014 to October. The auditory stimulation was created by using an audio music tape provided 20-minute per day for 7 consecutive days. In data analysis, SPSS WIN 21.0 program was utilized for descriptive statistics, repeated measurement anova and Mann-Whitney. Results: General characteristics of the two groups showed no significant differences, thus two groups were found to be homogenous. There were no significant differences in heart rate and respiration rate between the auditory and control groups. Conclusion: The effect of auditory stimulation for 7 days was not effective in decreasing heart rate or respiration rate in premature infants. Therefore, the type and length of music therapy must be developed for the improvement of vital signs in preterm infants who were hospitalized in a neonatal intensive care unit.

• Transactions on Electrical and Electronic Materials
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• v.16 no.1
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• pp.42-45
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• 2015

The ability to take electrocardiographic measurements while performing our daily activities has become the people-choice for modern age vital sign sensing. Currently, wet and dry ECG electrodes are known to pose threats like inflammations, allergic reactions, and metal poisoning due to their direct skin interaction. Therefore, the main goal in this work is to implement a very small ECG sensor system with a capacitive coupling, which is able to detect electrical signals of heart at a distance without the conductive gel. The aim of this paper is to design, implement, and characterize the contactless ECG electrodes. Under a careful consideration of factors that affect a capacitive electrode functional integrity, several different sizes of ECG electrodes were designed and tested with a pilot ECG device. A very small cotton-insulated copper tape electrode ($2.324cm^2$) was finally attained that could detect and measure bioelectric signal at about 500 um of distance from the subject's chest.

• Journal of Welding and Joining
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• v.19 no.3
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• pp.311-316
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• 2001

This paper presents that the affecting factors to the solderability and initial reliability. It is the factor that the coefficient of thermal expansion between package and PCB(Printed Circuit Board), the quantity of solder paste and reflow condition, and Au thickness of the solder ball pad on polyimide tape. As the reflow soldering condition for 48 ${\mu}BGA$ is changed, it is estimated that the quantity of Au diffusion at eutectic Sn-Pb solder surface and initial bonding strength of eutectic Sn-Pb solder and lead free solder. It is the result that quantitative measurement of Au diffusion quantity is difficult, but the shear strength of eutectic Sn-Pb solder joint is 842 mN at first reflow and increases 879 mN at third reflow. The major failure mode in solder is judged solder fracture. So, Au diffusion quantity is more affected by reflow temperature than by the reflow times.

• Progress in Superconductivity and Cryogenics
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• v.21 no.4
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• pp.48-52
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• 2019

Recently, many studies have been reported on the magnetoresistance and Hall effect of REBCO thin films and bulk. The voltage interferes quench detection of high-temperature superconducting magnet and generates leakage current in no insulation high-temperature superconducting coil. Therefore, in this paper, experiments on magnetoresistance and Hall effect of commercial YBCO and GdBCO tapes have been carried out. As a result, anomalous voltages expected for the magnetoresistance and Hall effect of REBCO tapes were observed and analyzed. In addition, the voltage characteristics of REBCO have been identified, and the Hall coefficient are calculated for use in high magnetic field magnet applications.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.07a
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• pp.286-287
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• 2005

Critical current(Ic) degradation of HTS tapes and AC loss under mechanical load is one of the hottest issues in HTS development and application. Mechanical load reduces the critical current of superconducting wire, and the Ie degradation affects the AC loss of the wire. We measured the Ie degradation and AC loss under tension and bending of Bi-2223 tapes processed by "Powder-in-Tube" technique at 17K with self-field. And we have studied the frequency dependence of self-field AC loss in multi-filamentary Bi-2223/Ag tape at 77K. The measurement results and discussions on the relationship between Ic degradation and AC loss are presented.

• Progress in Superconductivity and Cryogenics
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• v.20 no.4
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• pp.36-40
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• 2018

In this study, the electromechanical properties in Sn-Cu double layer stabilized GdBCO coated conductor (CC) tapes with and without external lamination under uniaxial tension were examined at 77 K and self-field. Their irreversible stress and strain limits were determined using a loading-unloading scheme based on different critical current ($I_c$) recovery criteria. The repeated tests were performed and statistical estimation was done to check the reproducibility depending on the criterion adopted in evaluating the electromechanical properties. From the results, it showed that the Sn-Cu double-layer stabilized CC tapes have the higher irreversible stress limit, but lower irreversible strain limit as compared to brass laminated ones. Through the repeated tests, it can be found that a small scattering of irreversible limits existed in both CC tape samples. Finally, similar strain sensitivity of $I_c$ in both CC tapes was obtained.