• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2013.05a
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• pp.104-104
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• 2013

고분자이면서 유전체인 Poly-Tetra-Fluoro-Ethylene (PTFE) 튜브에 AC형 고전압을 인가하여 유전체 장벽 방전 (dielectric barrier discharge, DBD)를 유도하고, 발생된 마이크로 플라즈마에 의한 PTFE 튜브 내벽의 표면 개질에 관한 연구이다. 가스인입과 진공배기가 가능한 장치에 PTFE 튜브를 연결하고, 튜브내부를 진공상태를 유지하면서 반응가스를 이용하여 튜브 내벽을 표면개질 하였다. 반응가스를 아르곤, 수소, 아세틸렌, 산소, 질소를 반응 단계에 맞게 혼입하여 마이크로 플라즈마를 발생시켜 플라즈마에 의한 표면변화를 관찰하였다. 표면은 반응성 가스 플라즈마에 의해 물리 화학적 반응이 일어나 고분자 표면의 반응성 활성화를 통한 표면개질의 방식으로 진행되었다. 표면 개질된 튜브 내벽 표면에 대해 XPS, FT-IR, SEM, 접촉각 측정과 분석 실시함으로써 표면변화를 관찰하였다.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2001.09a
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• pp.208-211
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• 2001

Geosynthetic Clay Liners (GCLs) have been used for the applications of the hydraulic containment system in landfill due to inexpensive costs, simple workability and distinguished ability as a barrier material. However, bentonite of GCLs is easy to be damaged by the chemical solutions. Thus, there is a need to evaluate the potential susceptibility of GCLs causing Increase the hydraulic conductivity when GCLs are exposed to raw leachate and dissolved humic substances from landfill leachate. The hydraulic conductivity tests were performed with flexible-wall permeameter (the falling -headwater/rising -tailwater procedure) in order to verify the potential susceptibility of GCLs. The values of the hydraulic conductivity conducted with raw leachate as a permeant liquid increased considerably; however, The change of the hydraulic conductivity in the case of humic and fulvic acid were not worthy of notice. As the results of swelling tests of bentonite, however, humic substances can affect badly on the dispersion behavior of bentonite. These results indicate that humic substances dissolved in leachate could reduce the hydraulic conductivity of GCLs in landfill.

• Proceedings of the Korean Geotechical Society Conference
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• 2006.03a
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• pp.1204-1209
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• 2006

Grouting operate to reinforce expanded clay ground. Cement grouting is one of the most frequently used techniques for underground construction. This work is going to use to add an electrolytic ion to boring water for expanded reduction. To construct underground structures on expanded clay ground is operated pre-grouting that it is the barrier wall previous excavation to prevent an accident. Grouting for early compressive strength development is made a type of suspension. That grouting aims to prevent the swelling magnification in length of time. From now on, grouting is became a type of higher strength suspension to develop early compressive strength.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2000.06a
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• pp.1823-1828
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• 2000

Power transformers, air-intakes, stacks in a combined thermal power plant are the main noise sources. Power transformer noise among them has being get a target of public complaint due to 480Hz component of its pure tone. The source is mainly magnetostrictive vibration of the transformer core. The first countermeasures was installing sound barrier on the front of transformer. However, 500Hz, center of the frequency is not reduced. This paper includes the measurements of noise level at the near resident apartment, the identification of noise transfer and the countermeasures for noise sources. Cavity resonance type of noise reduction devices was installed on enclosuring wall of transformers. As a result, the noise level from transformer is reduced about 3dB.

• Archives of Plastic Surgery
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• v.44 no.1
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• pp.76-79
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• 2017

Necrotizing fasciitis (NF) is an aggressive soft-tissue infection involving the deep fascia and is characterized by extensive deterioration of the surrounding tissue. Immediate diagnosis and intensive treatment, including debridement and systemic antibiotics, represent the most important factors influencing the survival of NF patients. In this report, we present a case of NF in the abdomen due to an infection caused by a perforated small bowel after abdominal liposuction. It was successfully treated using negative-pressure wound therapy, in which a silicone sheet functioned as a barrier between the sponge and internal organs to protect the small bowel.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2014.11a
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• pp.199-199
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• 2014

좁은 관경을 갖는 상대 유전율 3 이하인 PTFE와 PE 고분자 튜브 내부에 플라즈마 방전을 일으켜 고분자 튜브 표면 그래프팅 기술을 개발 하고자 하였다. 스텐트 및 인공혈관 등에 적용이 가능한 내부지름 3 mm 이하의 원통형 고분자 생체 식립체 내부 표면을 그래프팅하는 기술이다. 좁은 고분자 튜브 내부에 생성되는 방전은 고분자의 관경에 의해 방전개시 전압이 결정되었다. 방전개시 이후 DC glow discharge 에서 나타나는 전압과 전류의 특징들이 나타났다. 전압과 전류의 파형 분석에서는 고분자 표면과 가스 간의 새로운 용량성 임피던스가 형성되는 것을 관찰하였다. 고분자 내부 표면에 플라즈마의 방전 형태는 면 방전 (surface discharge)의 형태로 나타났다.

• Journal of electromagnetic engineering and science
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• v.2 no.2
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• pp.105-111
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• 2002

New high-performance Ka-band waveguide-to-microstrip transitions for millimeter-wave transceiver applications have been developed and characterized. These transitions are probe-type, but the dielectric material completely covers the whole waveguide aperture, thus providing moisture-barrier and robustness in the probe section. The new probe transitions are also designed to be less sensitive to fabrication tolerances. Further performance enhancements have been obtained by placing vias around the waveguide aperture. Also, the resonance phenomena associated with waveguide wall-penetration have been identified. The developed probe transitions provide insertion loss less than 0.4 dB over entire Ka-band frequencies, but can be optimized for narrowband applications with insertion loss less than 0.2 dB.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.15 no.5
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• pp.346-351
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• 2003

This paper aims at suggesting design guidelines for a perimeter-less HVAC system that contributes energy savings. Perimeter-less HVAC system is one that relieves difficulties fuck as handling mixing loss, uneven radiative environment, and maintenance and repair. It prevents heat load gained through window and outdoor wall without modifying a previously equipped building skin system. In this paper, we performed several kinds of CFD (computational fluid dynamics) cases through numerical simulation to obtain an optimized perimeter-less design, and then we conducted a large-scale model experiment to see how the push-pull air flow would handle indoor heat to obtain an optimized perimeter-less design.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.05a
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• pp.165-167
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• 2002

Stable reset and address discharge are very important when they show apparent display. But the shape of reset and address discharge and wall-charge distribution change, according to the variation on temperature. Namely, it is very difficult to show exact picture. This study represents how Dynamic Margin is height and dielectric thickness. When barrier rib height is $100{\mu}m$ and dielectirc thickness is $40{\mu}m$, it is responded the most sensitively by decreasing temperature.

• Korean Journal of Veterinary Research
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• v.44 no.4
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• pp.615-619
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• 2004

A three years old male Jackass penguin(Spheniscus demersus) showed anorexia, depression, respiratory problem for a few days, followed by clinical treatment for 20 days resulted in death. Grossly, multiple white nodules measuring 2~3 mm in diameter were observed in the surface of and inside lung, liver, kidney, thoracic wall. Microscopically, granuloma formations were observed in the lung and liver. The margin of granuloma surrounded by connective tissue barrier and infiltrated lymphocytes, and also observed giant cell near the granuloma. By Periodic acid Schiff reaction, hyphae were detected in granuloma of lung and liver. This case was a chronic and systemic aspergillosis caused by Aspergillus fumigatus infection in a Jackass penguin at a zoo.