• Proceedings of the KIEE Conference
• /
• 2003.07b
• /
• pp.825-827
• /
• 2003

There are many problems when air core reactor is used. Especially, measure instruments are influenced from magnetic field. This paper shows the research results for the magnetic field shielding on air core reactor.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.34 no.6
• /
• pp.675-681
• /
• 2010

It is well known that mesenchymal stem cell(MSCs) can be differentiated into fibroblasts, chondrocytes, and osteoblasts and that they develop into fibrous tissue, cartilage, or bone, as a result of mechanical stimulation. In this study, we developed a bioreactor system, which is composed of a reactor vessel that provides the required cell culture environment, an environment controlling chamber to control the media, a gas mixer, and a reactor motion control subsystem to apply mechanical stimuli to the cells. For the MSC culture, We used a poly-urethane (PU) scaffold, with a collagen coating to ensure improved cohesion ratio. Then, we transferred the cultivated MSCs in the PU scaffold, cultured the cells in the bioreactor system, and confirmed the proliferation, differentiation, and ossification processes, resulting from mechanical stimuli.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.14 no.4
• /
• pp.65-72
• /
• 2000

This paper proposes a Push type High Frequency DC-DC Converter using Zero Voltage Switching to reduce turn on and off loss at the switching instants. This paper has a advantage which is able to operating safely in load short, because DC reactor is connected with resonance reactor in order to supply a fixed safely in load short, because DC reactor is connected with resonance reactor in order to supply a fixed current with low ripple from DC power supply. The capacitor $(C_1, C_2)$ connected in switch are a common using as resonance capacitor and ZVS capacitor. The analysis of the proposed high frequency resonance DC-DC converter is generally described by using normallized parameter, and we has evaluated characteristic values which is needed to design a circuit. We conform a rightfulness of theoritical analysis by comparing a theoretical values and experimental values obtained from experiment using MOSFET as switching devices.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.17 no.1
• /
• pp.86-93
• /
• 2003

This paper describes that the resonant tank type DC-DC converter consist of reactor and capacitor resonant tank circuit for increased the output current. This circuit configuration is composed of the resonant tank circuit used resonant capacitor and reactor and the capacitor connected in switch are a common using by resonance capacitor and ZVS(Zero Voltage Switching) capacitor. Therefore, the proposed converter can reduce a switching losses, noise, and voltage stress at turn-on and turn-on and has an advantage which is able to operating safely in load short, because DC reactor is connected with resonance reactor in order to supply a fixed current with low ripple from DC power supply. The analysis of proposed circuit uses normalized parameters and characteristic estimation is generally described the proposed circuit with the characteristics of power and output voltage etc. Also, design is based on the characteristic estmations in each step. Hence, We conform a rightfulness theoretical analysis by comparing a theoretical values and experimental values obtained from experiment.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.16 no.5
• /
• pp.477-483
• /
• 2011

Existing switching system that is one of the ways which are used for DC/DC power converter is classified to hard-switching system and resonant-soft-switching system, generally. Hard-switching system is inefficient because the power loss of the switching element is large when it is been to trun on or turn off. And resonant-soft-switching system have the defect that need to add the another reactor and capacitor that make it expensive and huge. This paper suggest the ZVS Full-Bridge power converter contrcution of novel switching system for the overcoming these shortcomings. In Suggested soft-switching system, the front of buck converter at diode current, switch is changing on and off at the part of full-bridge converter's zero voltage part. as the result that is possible to be ZVS excepting the reactor and capacitor. also to verify the reasonability of the isolated ZVS full-bridge DC/DC converter as previously suggested, we produced the 500[W] level DC/DC converter and enforced the simulation for Psim, and then it able to conform the superiority of the DC/DC converter's efficient.

• Journal of the Korean Geotechnical Society
• /
• v.36 no.5
• /
• pp.17-24
• /
• 2020

In order to analyze the effect of applying the bioreactor landfills on the waste landfill for acceleration of waste biocompression, a settlement experiment was performed. The secondary compression indices (C_α) were analyzed, and compared with the results of experimental studies conducted in other countries. Analyses of C_α from the experiment showed that the recirculation method of mixing leachate and FWL could accelerate the waste settlement as much as 2.9 times and 2 times more than the leachate recirculation and the sanitary landfills due to additional biocompression generated by the organic matter in FWL. The C_α in this study was smaller than the C_α of the other studies due to the low organic content of the waste in accordance with domestic waste policies to reduce food waste. The relation between biodegradable waste content and C_α was analyzed. The C_α of the waste was shown to be sensitive to biodegradable waste content, and become higher as the content of the biodegradable waste increases.

• Proceedings of the KIEE Conference
• /
• 2002.07b
• /
• pp.619-621
• /
• 2002

In this paper, AC reactor for PWM converter using the metal powder is introduced. Metal powder AC reactor was developed to substitute conventional iron core typed AC reactor in the PWM converter application. The characteristics of the metal powder AC reactor are analyzed and tested. A new reactor has reduced switching noise and loss.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.26 no.2
• /
• pp.92-98
• /
• 2012

As the increasing of non-linear load, filter is coming to be high gradually in order to reduce the harmonic which occurs from the power conversion. The maintenance of passive filter is easier than active filter and it has been widely used in the industrial site. This passive filter is connected with condenser and reactor by series and parallel and it is installed at the front of nonlinear load. The breakdown of passive filter occurs frequently at the reactor side rather than capacitor. So the breakdown cause close examination is necessary. In this paper, we analyzed that the electric stress of reactor which is considered magnetization saturation at the passive filter. We confirm that the reduction of harmonics and the electric stress of reactor is influenced by the linear and non-linear element of reactor.

• Proceedings of the KIPE Conference
• /
• 2016.07a
• /
• pp.147-148
• /
• 2016

본 논문에서는 원격 플라즈마 발생장치 (Remote Plasma Generator, RPG)에 적용하기 위한 공진형 토폴로지에 대해 비교한다. 원격 플라즈마 발생장치는 AC-DC 정류기, DC-AC 인버터, 공진탱크, 플라즈마 발생용 리액터, 점화장치로 구성되며, 이는 기존의 SMPS와 유사한 구성이다. 하지만 플라즈마 부하는 기존의 전력전자 어플리케이션들과는 달리 점화조건과 플라즈마 유지 조건을 충족시켜야 한다는 특징이 있다. 따라서 본 논문에서는 각 공진형 토폴로지들의 특성 비교 분석을 통해 원격 플라즈마 발생장치에 대한 적용 가능성에 대한 분석을 수행하였으며, 시뮬레이션을 통해 검증하였다.

• Proceedings of the KIEE Conference
• /
• 1990.11a
• /
• pp.210-213
• /
• 1990

This paper presents the countermeasure to present the main transformer of distribution substation from deteriorating and failing due to repeated magnetic force of the transformer winding by ground fault current in 22.9kV multi grounded distribution system. The Winding strength to the short circuit current is designed to be endurable to the stress of over current. But this design is related to the manufactures. In this paper we examine the application of shunt reactor to the neutral point of the low side of the transformer to reduce fault current due to the fault in the distribution lines we have analysed the fault characteristics of the system and calculated the optimum ohmic values of the neutral reactor.