• Progress in Superconductivity and Cryogenics
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• v.1 no.1
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• pp.28-32
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• 1999

We have performed an EMTDC simulation for the current limiting effects of a superconducting fault current limiter (SFCL). The fault currents in the 154 kV transmission line between the arbitrary S1 and S2 substations increased up to 54 KA and 60 KA during the line-to-line and three phase faults, respectively. The SFCL with 100$\omega$ of resistance after quench limited the currents to less than 17 KA within a half cycle. This limited current is well below the upper limit of a circuit breaker, suggesting that the resistance of the SFCL in the transmission line is sufficient.

• Proceedings of the KIEE Conference
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• 1998.11a
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• pp.242-244
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• 1998

We have performed an EMTDC simulation for the current limiting effects of a superconducting fault current limiter (SFCL) for the 154 kV transmission line between the Gaepo and Sungnam substations. The simulation showed that a line-to-line fault increases the fault current up to 54 kA. The SFCL with $100{\Omega}$ impedance after quench limited the current to 15 kA within a half cycle. This limited current is well below the upper limit of a circuit breaker, suggesting that the impedance of the SFCL in the transmission line is sufficient.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.18 no.3 s.118
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• pp.265-272
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• 2007

In this paper, a frequency changeable antenna using dual half wavelength loaded line structure is proposed for multiband mobile handset applications. The proposed antenna has a capability of independent frequency shift by controlling two added inductance values in two different bands. Experimental results indicate that the proposed antenna provides enough effective bandwidth to cover $CELLULAR(824\sim894\;MHz)$, $EGSM(880\sim960\;MHz)$, $DCS1800(1,710\sim1,880\;MHz)$, $PCS1900(1,850\sim1,990\;MHz)$ and $WCDMA(1,920\sim2,170\;MHz)$ bands and peak gain variation is only 0.54 dB.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.2
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• pp.278-283
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• 2013

With the increasing power demands, size of the fault current in electrical grids is steadily increasing, and it exceeds the breaking capacity of circuit breakers. To effectively cope with these problems, a high-speed interrupter was suggested. The high-speed interrupter provides fault current with a bypass to a fault current limiter in case of accidents and consequently, fault current can be restricted. In this study, behavioral characteristics of high-speed interrupter were analyzed by accident types occurred in a distribution system. When accidents occurred, a and b contact of the high-speed interrupter were turned-off and then, turned-on. Accordingly, fault current flowed to the circuit connected to a current limiting element, and the fault current limiter restricted fault current to within a half-cycle. Nevertheless, the behavior of the high-speed interrupter was slowed down by a switching surge. As a result, fault current was confirmed to be restricted not to within the anticipated half-cycle, but to after a half-cycle. Moreover, the behavioral characteristics of the high-speed interrupter changed not only by accident types, but by behaviors of R, S, and T phases. This was due to the errors in stroke lengths of the high-speed interrupters, which resulted in a slight time discrepancy among three interrupters. In addition, the switching behaviors of the b and a contact were confirmed not to have coincided due to the switching surge; b contact behaved first and a contact followed. because of this, accuracy of stroke length and switching surges through the solenoid suction increases may be necessary to resolve.

• The Bulletin of The Korean Astronomical Society
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• v.37 no.2
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• pp.113.1-113.1
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• 2012

The characteristics of Doppler shifts in a quiet region of the Sun are investigated by comparing between the $H{\alpha}$ line and the Caii infrared line at 854.2 nm. A small area of $16^{\prime\prime}{\times}40^{\prime\prime}$ was observed for about half an hour with the Fast Imaging Solar Spectrograph (FISS) of the 1.6 meter New Solar Telescope (NST) at Big Bear Solar Observatory. The observed area contains a network region and an internetwork region, and identified in the network region are $H{\alpha}$ fibrils, Caii fibrils and bright points. We infer the Doppler velocity from each line profile at a point with the lambdameter method as a function of half wavelength separation ${\Delta}{\lambda}$. It is confirmed that the bisector of the spatially-averaged Caii line profile has an inverse C-shape of with a significant peak redshift of +1.8 km/s. In contrast, the bisector of the spatially-averaged $H{\alpha}$ line profile has a different shape; it is almost vertically straight or, if not, has a C-shape with a small peak blueshift of -0.5 km/s. In both the lines, the bisectors of bright network points are much different from those of other features in that they are significantly redshifted not only at the line centers, but also at the wings. We also find that the spatio-temporal fluctuation of Doppler shift inferred from the Caii line is correlated with those of the $H{\alpha}$ line. The strongest correlation occurs in the internework region, and when the inner wings rather than the line centers are used to determine Doppler shift. In this region, the RMS value of Doppler shift fluctuation is the largest at the line center, and monotonically decreases with ${\Delta}{\lambda}$. We discuss the physical implications of our results on the formation of the $H{\alpha}$ line and Caii 854.2 nm line in the quiet region chromosphere.

• Journal of Ocean Engineering and Technology
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• v.8 no.1
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• pp.114-122
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• 1994

X-ray stress constant, K, was determined for the diffraction line of (211)plane by using Cr-K$\alpha$ radiation. K was -340.87 MPa/deg. Fatigue crack propagation tests of SS41 steel were conducted under stress ratios of 0.1, 0.3 and 0.5. The half-value breadth of X-ray diffraction profile was measured at and beneath the fracture surface. The half-value breadth, B, on the fracture surface was found to increase with increasing $K_max$. The value of B was influenced by stress ratio in SS41 steel. The half-value breadth took the maximum value at the borden of reversed plastic zone, while it approached to the initial (pre-fatigue) value near the boundary of monotonic plastic zone. The maximum depth of the plasticzone was evaluated on the basis of the half-value breadth distribution. The depth $\omega$$_y$ is related to $K_max$by the following equation : $\omega$$_y$ = $\alpha$($K_max$/$\sigma$$_y$$)^2$ where .sigma.$\sigma$$_y$ is the yield strength obtength obtained in tension test .alpha.is 0.136 for SS41 steel.

• Journal of the Korean Society of Marine Environment & Safety
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• v.21 no.1
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• pp.97-102
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• 2015

The long line fishing machine is combined with motor and two disc rollers has used on the small size fishing-boat under 1 ton located in near Jeollanam-do seaside. The long line fishing motor is controlled only one direction because the fishing line is loaded heavily at pulling up. On this paper we made the long line fishing 400W power motor controller which it was usually applied under 1 ton fishing boat, and designed the controller using PWM chip, Half bridge driver and MOSFET for one direction motor control. Furthermore some user convenience devices were added like battery indicator and safety protection circuit for battery overdischarge and battery source wire mismatch connection. So we protected the battery from overdicharging when the battery voltage was below 11.5V and fishermen didn't need to worry about source lines misconnection anymore. We confirmed the test version of controller was the good working condition at land and sea.

• Therapeutic Science for Rehabilitation
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• v.3 no.2
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• pp.83-89
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• 2014

Objective : This study aims to investigate the effect of half- eyes patching for the reduction of unilateral neglect of left-side hemiplegia. Methods : This study used the ABA design. He was required to wear the half- eyes patching during all the period of ADL because unilateral neglect causes many problems in the majority of ADL. The assessments for the unilateral neglect had been performed by the Line bisection and the Albert test once a session (day). Results : Regarding the Means of the errors to the Line bisection and the Albert test, the Means of the errors was not decreased during the period of the intervention (B) and was not decreased after the withdrawal (A'). Conclusions : Half-eyes patching was non-effective to r e lease the unilateral neglect. Further study is necessary to increase the sample size and the duration of experiments.

• Korean Journal of Human Ecology
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• v.9 no.4
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• pp.471-482
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• 2000

The purpose of this study is to produce slacks pattern for pregnant women in the mid or second half period of their pregnancy according to the development figure of the body shell from a follow-up measurement. We here would like to produce slacks pattern for pregnant women constructed to fit better with their individual property in their figure and to help maintain the shape and beauty of the lower half of body and would compare it with two manufactured slacks pattern. The results of the study were as follows; 1. As the pregnancy proceeds, the height of natural-waist line went up spontaneously due to the projection of abdominal region, therefore, it was given darts at the front zipper part so that they could maintain a nice figure and to avoid possibility of feeling oppressed. To acquire a slimmer outfit, we made of the slacks-bottom narrower than the width at the knee line, and it worked out. 2. Sensory evaluation for appearance: According to the statistical of the result of 19items on the questionaire, all items showed significant difference(a$\leq$0.01) between the new and A(bunka) B(Kim's pattern) method slacks pattern, with the new pattern having higher scores. The new drafting method proved to be better fitted, to fit the shape of bodies properly and to get a visual effect to look slim.

• The Transactions of the Korean Institute of Power Electronics
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• v.16 no.3
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• pp.293-301
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• 2011

This paper proposes a bridgeless half-bridge AC-DC converter with high-efficiency. The proposed converter integrates the bridgeless power factor correction (PFC) circuit with the asymmetrical pulse-width modulated (APWM) half-bridge DC-DC converter. It provides the isolated DC output voltage from the AC line voltage without using any full-bridge diode rectifier. Conduction losses are lowered with a simple circuit structure. Switching losses are also reduced by achieving zero-voltage switching (ZVS) of the power switches. By using series-connected two transformers, the proposed converter provides a low-profile and high power density for AC-DC converters. The performance of the proposed converter is verified from a 250 W (48 V / 5.2 A) experimental prototype circuit at $90 \;V_{rms}$ line voltage.