• Proceedings of the KIPE Conference
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• 2017.11a
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• pp.11-12
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• 2017

본 논문에서는 전기자동차 800V/14V LDC용 낮은 전압정격을 갖는 소프트 스위칭 컨버터를 제안한다. 제안하는 컨버터는 입력이 직렬구조로써 입력전압의 절반으로 낮은 스위치의 전압정격을 갖기 때문에 도통손실과 스위칭 손실 저감 효과를 갖고, 넓은 입력전압 및 부하영역에서 소프트 스위칭을 성취하여 높은 효율을 달성할 수 있으며 변압기의 직렬연결로 된 커패시터로 인해 자화전류의 오프셋이 없다. 제안하는 소프트 스위칭 컨버터의 동작원리를 제시하고 시작품을 통해 본 논문의 타당성을 검증하였다.

• Journal of Power Electronics
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• v.14 no.3
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• pp.478-487
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• 2014

This study presents a new interleaved three-level zero-voltage switching (ZVS) converter for high-voltage and high-current applications. Two circuit cells are operated with interleaved pulse-width modulation in the proposed converter to reduce the current ripple at the input and output sides, as well as to decrease the current rating of output inductors for high-load-current applications. Each circuit cell includes one half-bridge converter and one three-level converter at the primary side. At the secondary side, the transformer windings of two converters are connected in series to reduce the size of the output inductor or switching current in the output capacitor. Based on the three-level circuit topology, the voltage stress of power switches is clamped at $V_{in}/2$. Thus, MOSFETs with 500 V voltage rating can be used at 800 V input voltage converters. The output capacitance of the power switch and the leakage inductance (or external inductance) are resonant at the transition interval. Therefore, power switches can be turned on under ZVS. Finally, experiments verify the effectiveness of the proposed converter.

• Journal of Power Electronics
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• v.14 no.4
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• pp.661-670
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• 2014

A new DC/DC converter with zero voltage switching is proposed for applications with high input voltage and high load current. The proposed converter has two circuit modules that share load current and power rating. Interleaved pulse-width modulation (PWM) is adopted to generate switch control signals. Thus, ripple currents are reduced at the input and output sides. For high-voltage applications, each circuit module includes two half-bridge legs that are connected in series to reduce switch voltage rating to $V_{in}/2$. These legs are controlled with the use of asymmetric PWM. To reduce the current rating of rectifier diodes and share load current for high-load-current applications, two center-tapped rectifiers are adopted in each circuit module. The primary windings of two transformers are connected in series at the high voltage side to balance output inductor currents. Two series capacitors are adopted at the AC terminals of the two half-bridge legs to balance the two input capacitor voltages. The resonant behavior of the inductance and capacitance at the transition interval enable MOSFETs to be switched on under zero voltage switching. The circuit configuration, system characteristics, and design are discussed in detail. Experiments based on a laboratory prototype are conducted to verify the effectiveness of the proposed converter.

• 한국초전도학회:학술대회논문집
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• v.15
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• pp.85-85
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• 2005

• 한국초전도학회:학술대회논문집
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• v.16
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• pp.84-84
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• 2006

• Journal of Power Electronics
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• v.14 no.4
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• pp.742-753
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• 2014

In this paper, a new continuously and linearly controlled capacitive static VAR compensator is proposed for the automatic power factor correction of inductive single phase loads in 220V 50Hz power system networks. The compensator is constructed of a harmonic-suppressed TCR equipped with a new adaptive current controller. The harmonic-suppressed TCR is a new configuration that includes a thyristor controlled reactor (TCR) shunted by a passive third harmonic filter. In addition, the parallel configuration is connected to an AC source via a series first harmonic filter. The harmonic-suppressed TCR is designed so that negligible harmonic current components are injected into the AC source. The compensator is equipped with a new adaptive closed loop current controller, which responds linearly to reactive current demands. The no load operating losses of this compensator are negligible when compared to its capacitive reactive current rating. The proposed system is validated on PSpice which is very close in terms of performance to real hardware.

• Progress in Superconductivity
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• v.7 no.2
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• pp.114-119
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• 2006

High critical current density, high n value, multiple faults endurances, and fast recovery characteristics of YBCO thin films are very attractive characteristics for developing resistive type superconducting fault current limiters. But due to the limited current and voltage ratings of one YBCO module, it is needed to construct series and parallel module connections for high capacity electric networks. Especially for distribution network, more than 30 units should be connected in series to meet voltage level. So in order to construct distribution-level superconducting fault current limiter, simultaneous quench in one YBCO thin films should be realized, and furthermore, quench should be occurred in all fault current limiting units equally to avoid local heating and failures. In this paper, we proposed optimum design of YBCO thin films for fault current limiting module and technical method using shunt resistor to achieve simultaneous quench between multi current limiting units. From the analytical and the experimental results, optimal current path and thickness of shunt material was determined for YBCO thin films and shunt resistor between modules was developed. Finally, 14 kV one phase resistive fault current limiter using multi YBCO thin films was constructed and it was possible to get satisfactory test results.

• Journal of Physiology & Pathology in Korean Medicine
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• v.25 no.2
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• pp.257-263
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• 2011

This study was designed to investigate the effects of Hominis placenta pharmacopuncture treatment and electroacupuncture therapy on the functional recovery and histological change, protein expression in spinal cord injury(SCI) rats. Experimental groups were divided into the Group I(normal control rat), Group II(Non-treatment after spinal cord injury induction), Group III(Hominis placenta pharmacopuncture treatment after SCI induction), Group IV (Electroacupuncture therapy after SCI induction), Group V(Hominis placenta pharmacopuncture treatment and electroacupuncture therapy after SCI induction). After operation, rats were tested at modified Tarlov test at 1 to 3 days with divided into 4 groups, and motor behavior test(BBB locomotor rating scale, Grid walk test) was examined at 3, 7, 14, and 21 days. For the observation of damage change and size of the organized surface in muscle and spinal cord, histopathological studies were performed at 21 days by H & E stain, and BDNF & NT-3 protein expression studies were performed at 21 days. Acco rding to the results, Hominis placenta pharmacopuncture treatment and electroacupuncture therapy can play a role in facilitating recovery of locomotion following spinal cord injury. Specially, Hominis placenta pharmacopuncture treatment and electroacupuncture combimed therapy after SCI induction was most improvement in functional recovery, BDNF, and NT-3 protein synthesis.

• The Korean Journal of Pain
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• v.8 no.2
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• pp.251-256
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• 1995

Opioids produce strong analgesic effect result with some side effects such as nausea, vomiting, urinary retention, somnolence, and respiratory depression. Nalbuphine, an agonist-antagonist has, at low doses, an analgesic potency comparable to morphine with little side effects. Analgesic effect after continuous infusion of fentanyl-ketorolac-droperidol, or $Nubain^{(R)}$-ketorolac-dropertiodl combination in Cesarean section patients were assessed by numerical rating scale (NRS) and Prince Hednry scale (PHS). The patients were divided into two groups. Each group consists of 30 patients. Group 1 received 20 ${\mu}g$ of fentanyl the end of surgery. And then continuously infused with additional 380${\mu}g$ of fentanyl plus 120 mg of ketorolac and 2.5 mg of droperidol. Group 2 initially received 2 mg of $Nubain^{(R)}$ at the end of surgery and the remaining dose of $Nubain^{(R)}$ 38 mg plus ketorolac 120 mg and droperidol 2.5 mg was continuously infused. With all patients, initial dose of drug was administered by bolus of i.v. injection and the remaining dose was administered via i.v. using a Baxter Two $Infusor^{(R)}$. Pain scores and side effects were recorded at the time of recovery room arrival, and at interval of 30 min, 1 hr, 6 hr, 14 hr, 24 hr, 48 hr after start of continuous infusion. No significant difference was found between the pain scores and side effects of both groups although pain control effect was excellent in both groups. We concluded that $Nubain^{(R)}$ could be an alternative to fentanyl for postoperative pain control.

• Journal of the Korean Society of Clothing and Textiles
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• v.31 no.12
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• pp.1689-1699
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• 2007

The purpose of the research was to explore clothing characteristics that tween girls(ages 9-14) consider important when deciding what to wear, as well as what the tween girls' mothers believe that their daughters value. The purposive sample consisted of 41 mother-daughter pairs recruited by $[TC]^2$ (Textile/Clothing Technology Corporation). Subjects were divided into younger(9-11) and older(12-14) normal- and plus-size groups based on Body Mass Index(BMI). There were significant differences between mothers and daughters in rating the importance of seven decision criteria concerning what to wear. The entire tween girls reported that clothes that fit well as the most important criteria in deciding what to wear. Clothes that were comfortable was the only criterion significantly related to the tween girls' body dissatisfaction scores. Mothers rated clothes that are the newest fashion and that friends would be wearing as being significantly more important than their daughters reported. There was a significant negative correlation between tween girls' body dissatisfaction scores and choosing clothes that are comfortable. Normal-size tweeen girls and their mothers differed significantly only when considering the newest fashion and what friends would be wearing. Plus-size tween girls and their mothers differed significantly for four criteria: fit, comfort, best looking, and what friends would be wearing. Both younger and older groups differed with mothers concerning what friends would be wearihng. Additionally, younger girls placed significantly more emphasis than their mothers fit. Older girls did not consider the newest fashion an important a decision criterion, but their mothers believed that they did.