• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2009년도 추계학술대회 논문집
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• pp.479-480
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• 2009

• 한국균학회지
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• 제15권3호
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• pp.135-141
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• 1987

원형질체 융합에 의한 식용버섯의 유전육종연구는 종래의 전통적 육종방법인 균사융합으로는 해결할 수 없는 균주간의 불화합성 장벽을 능가하여 새로운 품중육성에 그 기대가 크다. 한국의 주요재배 버섯이며, 날로 세계의 재배면적이 증가하는 느타리버섯류의 유전육종을 위하여 몇가지 종간의 체세포 잡종의 선발과 이들의 유성에 대하여 조사한 결과는 다음과 같다. 1. 이 종간 원형질체 융합으로 체세포 잡종을 선발하였는데, 느타리+노랑느타리, 느타리+사철느타리, 느타리+여름느타리, 사철느타리+노랑느타리, 사철느타리+여름느타리 그리고 여름느타리+노랑느타리의 원형질체 융합율은 0.002-3.25%였으며, MCM과 MCM+benomyl에서 융합주의 균총분리가 일어나지 않았다. 2. 화합성 균주간에는 균사융합 및 원형질체 융합에 의하여 모두 균사체에 clamp connection을 형성하였으며, 자실체도 형성하였다. 그러나 불화합성 균주간에는 균사 및 원형질체 융합에 의하여 clamp connection을 확인할 수 없었으며, 자실체도 형성하지 않았다. 3. clamp connection이 없고 자실체도 형성하지 않는 원형질체 융합주의 임성을 유도하기 위하여, 이들 모균주와 균사융합한 결과 단핵균주와는 드물게 clamp connection을 형성하였으며, 이 핵균주와는 모두 clamp connetion을 형성하였다. 4. 불화합성 균주간의 원형질체 융합주는 새로운 불화합성을 형성하였는데, ASI 2-3+ASI 2-53의 P148은 ASI 2-3과 화합성인 ASI 2-1, ASI 2-2와 불화합성을 나타냈다. 또한 ASI 2-3+ASI 2-44의 P150은 ASI 2-3과 화합성인 ASI 2-1, ASI 2-2와 불화합성이었다.

• 조명전기설비학회논문지
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• 제15권6호
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• pp.49-57
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• 2001

본 논문에서는 single-stage, two-stage 두가지 역률보상(PFC)기법을 기존의 능동 클램프 플라이백 컨버터에 적용하여 역률개선을 하였다. 삽입된 플라이백 컨버터의 능동클램프회로가 주스위치와 보조스위치의 영전압스위칭(ZVS)을 구현하며, 스위칭 손실을 줄임으로써 고효율을 얻을 수 있고, 높은 주파수에서의 스위칭이 가능하다. 하지만 일반적으로 사용되는 다이오드정류기, 평활용커패시터에 의한 낮은 역률의 문제점이 남아있다. 본 논문에서는 300[W급] 능동 클램프 ZVS 플라이백 컨버터를 설계하여 single-stage two-stage방식을 적용, 입력역률개선을 시뮬레이션과 실험에 의해 입증하고자 한다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 춘계학술대회 논문집
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• pp.1626-1629
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• 2005

Recently many countries have concentrated their effort on the port automation, in order to be the Hub-port, that the Ultra Large Container Ship could come alongside the Quay, in their region. As the magnitude of the container ship increase, that of the Quay crane increases from 50ton-class to 61ton-class more and more. The wind speed criteria to design the structures used in the port was upgraded from 20m/s to 40m/s due to change of the weather condition. Our laboratory could have the ability to design the wedge type rail clamp for 50ton-class Quay crane in 30m/s wind speed. Accordingly we analyzed the load condition of the Quay crane about 40m/s wind speed upgraded from 20m/s and designed the wedge type rail clamp for 50ton and 61ton-class Quay crane.

• International Journal of Safety
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• 제6권2호
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• pp.22-26
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• 2007

An episode of corona is a heterogeneity-caused electric discharge that occurs when electric fields are formed layer on layer and concentrated on an electrode. Electric wires built at the tip of 154kV private facilities use dead end clamp spawns corona from homogeneity caused by field concentration. Corona induces power loss, noise, insulator failure and more. In this research, we've studied the characteristics of coronas that take place in porcelain insulators and terminal electric wires of supporting hard wares (dead end clamp) that are set up as spares in the 154kV private facilities use hydroelectricity installations to support electric wires. Corona, which cannot be identified by regular methods, was measured utilizing UV image camera. As the result of measuring corona via UV image camera, we've confirmed that the depletion of insulators was accelerated following the wire end treatment method and validated the stress intensity of insulators at various lengths of bare wires caused by electric fields via FEMLAB. We have also proposed a new model for relieving homogeneity-caused field concentration, and after analyzing the proposed model via FEMLAB, we've confirmed that the concentration of field distribution was indeed reduced. Such results are exploited in installation of private facilities use equipments, maintenance of insulators and hard wares as well as safety enhancement, and are anticipated to be effectively utilized in corona prevention measures.

• 전력전자학회논문지
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• 제9권6호
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• pp.560-567
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• 2004

이 논문에서는 Planar transformer를 적용한 30W급 포워드 컨버터에 대한 설계와 실험결과를 소개한다. 컨버터의 전체적인 크기와 체적은 일반적인 권선형 변압기 대신 Planar transformer를 적용함으로써 감소하였고 크기와 체적의 감소로 포워드 컨버터의 전력밀도가 증가하였다. 또한, Single Switch 포워드 컨버터 와 Active Clamp ZVS 포워드 컨버터를 비교연구 하였다.

• 항공우주시스템공학회지
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• 제9권2호
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• pp.7-12
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• 2015

In this paper, we report a non-explosive separation device for a small satellite which utilize a shape memory alloy actuator and spring clamp. In order to increase the preload, the proposed device employs spring clamp that can generate high toque when the shape memory alloy actuator makes the cylinder key unlatch a holding ball effectively. Owing to simple design of separation device configuration, we could obtain good repeatability(up to 30 times activation). Conclusively, we could develop a non-explosive separation device which can reliably activate within 1.2 sec under high preload(up to 300kgf).

• 전력전자학회논문지
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• 제17권6호
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• pp.500-506
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• 2012

In this paper, a non-isolated high step-up and high efficiency boost converter is proposed. By using the 3-level boost converter structure, the proposed converter can obtain higher voltage gain than conventional high step-up converters. The voltage spike of the switching device is well clamped by using the clamp circuit composed of a clamp diode and a capacitor and the energy of the leakage inductor of coupled inductor is effectively transferred to output. Due to the 3-level structure, the equivalent switching frequency of the coupled inductor is doubled, which results in reduced inductor size. A 500 W prototype converter is built and tested to verify performance of the proposed converter.

• Journal of Korean Neurosurgical Society
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• 제45권5호
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• pp.306-308
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• 2009

The Mayfield head clamp is the most frequently used head clamp system in the field of neurosurgery. In many cases, surgery is performed with complete reliance on the safety of the MHC. However, we experienced an extremely rare case in which the MHC accidentally broke while installing this system for immobilization of the head and neck. This is a case report with a brief review of the literature. The patient was a 58-year-old female who was scheduled to undergo cervical laminoplasty under the diagnosis of degenerative spondylotic cervical stenosis. In an attempt to install an MHC, we fixed three pins in the scalp; however, the arm of the MHC system broke when force was applied from both directions. Fortunately, the patient remained in a stable position and did not sustain an injury to the head or neck. Fixation was performed using another MHC, and the surgery was performed successfully. The patient was discharged after surgery with no specific complications related to the MHC system. The authors experienced an extremely rare case of MHC breakage during application and report the importance of properly managing and maintaining the instruments in order to prevent fatal injury.

• Journal of Power Electronics
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• 제6권2호
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• pp.131-138
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• 2006

An active clamp ZVS PWM forward converter using a secondary synchronous switch control is proposed in this paper. The proposed converter is suitable for low-voltage and high-current applications. The structure of the proposed converter is the same as a conventional active clamp forward converter. However, since it controls the secondary synchronous switch to build up the primary current during a very short period of time, the ZVS operation is easily achieved without any additional conduction losses of magnetizing current in the transformer and clamp circuit. Furthermore, there are no additional circuits required for the ZVS operation of power switches. Therefore, the proposed converter can achieve high efficiency with low EMI noise, resulting from soft switching without any additional conduction losses, and shows high power dens~ty, a result of high efficiency, and requires no additional components. The operational principle and design example are presented. Experimental results demonstrate that the proposed converter can achieve an excellent ZVS performance throughout all load conditions and demonstrates significant improvement in efficiency for the 100W (5V, 20A) prototype converter.