• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 하계학술대회 논문집 Vol.9
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• pp.121-122
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• 2008

Lithium Niobate (LN:LiNbO3) is a compound of niobium, lithium and oxygen. The characteristics of LN are piezoelectricity, ferroelectricity and photoelectricity, and which is widely used in surface acoustic wave (SAW). To manufacture LN device, the LN surface should be a smooth surface and defect-free because of optical property, but the LN material is processed difficult by traditional processes such as grinding and mechanical polishing (MP) because of its brittleness. To decrease defects, chemical mechanical polishing (CMP) was applied to the LN wafer. In this study, the suitable parameters scuh as pressure and relative velocity, were investigated for the LN CMP process. To improve roughness, the LN CMP was performed using the parameters that were the highest removal rate among process parameters. And, evaluation of optical property was performed by the optical reflectance and non-linear characteristic.

• 한국실내디자인학회논문집
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• 제15권6호
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• pp.150-158
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• 2006

The purpose of this study is to evaluate environment-friendly planning feature in Environment-friendly Certificated apartments and to use the basic planning data of housing. Seven Environment-friendly Certificated apartments have been analyzed. The findings of this study are as follows: Environment-friendly planning features are categorized into 4 items; floor planning feature, material planning feature, universal planning feature and environmental planning feature. Among floor planning features, natural sunlight, built-in closets, and differentiated floor plans are well considered, but the flexible floor plan for resident's lifestyle and green space are lack. Among material planning features, environment-friendly finishing materials, environment-friendly products and energy-efficient double-pane windows are well considered, but implementation for resource savings using recycled materials are lack. Among universal design planning features, removal of threshold and installation of safety device in bathroom are not well considered. Among environmental planning features, usage of alternative energy like solar energy are not applied. The environment-friendly planning features in interior space should be introduced in diverse ways.

• Journal of Mechanical Science and Technology
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• 제15권11호
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• pp.1588-1598
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• 2001

The effects of recirculated exhaust gas on the characteristics of NOx and soot emissions under a wide range of engine loads were experimentally investigated by using a four-cycle, four-cylinder, sw irl chamber type, water-cooled diesel engine operating at three engine speeds. The purpose of this study was to develop the EGR-control system for reducing NOx and soot emissions simultaneously in diesel engines. The EGR system is used to reduce NOx emissions, and a novel diesel soot removal device with a cylinder-type scrubber for the experiment system was specially designed and manufactured to reduce soot contents in the recirculated exhaust gas to the intake system of the engine. The experiments were performed at the fixed fuel injection timing of 4$^{\circ}$ ATDC regardless of experimental conditions. It was found that soot emissions in exhaust gases were reduced by 20 to 70% when the scrubber was applied in the range of the experimental conditions, and that NOx emissions decreased markedly, especially at higher loads, while soot emissions increased owing to the decrease in intake and exhaust oxygen concentrations, and the increase in equivalence ratio as the EGR rate is elevated.

• 한국기계가공학회지
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• 제16권5호
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• pp.40-46
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• 2017

A plasma gas control apparatus for semiconductor plasma etching processes securely holds a cathode for forming a plasma, confines the plasma during the plasma etching process, and discharges gas after etching. It is a key part of the etching process. With the advancement of semiconductor technology, there is increasing interest in parts for semiconductor manufacturing that directly affect wafers. Accordingly, in order to replace the plasma gas control device with a CVD-SiC material superior in mechanical properties to existing SiCs (Sintered-SiC, RB-SiC), a study on the grinding characteristics of CVD-SiC was carried out. It is confirmed that the optimal grinding condition was obtained when the result table feed rate was 2 m/min and the infeed depth was $5{\mu}m$.

• 한국수소및신에너지학회논문집
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• 제25권4호
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• pp.386-392
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• 2014

The effective water management in a polymer electrolyte membrane fuel cell (PEMFC) is one of the key strategies for improving cell performance and durability. In this work, an ex situ measurement was carried out to understand the water droplet behavior on the surface of gas diffusion layer (GDL) as a fundamental study for establishing novel water management. For that purpose, simplified cell including one rib and two flow channels was designed and fabricated. Using this ex situ device, the water droplet emergence through the GDL of the PEMFC was emulated to understand liquid water transport through the porous diffusion medium. Through the visualization experiment, the emergence and growth of water droplets at the channel/GDL interface are mainly observed with the surface characteristics of GDL (SGL 10BA, 24BA) and rib when the liquid water passes through the GDL and is expelled to the flow channel. It is expected that the results obtained from this study can contribute to the better understanding on the water droplet behavior (emergence and removal) in the flow channels of PEMFC.

• 조명전기설비학회논문지
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• 제15권1호
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• pp.98-103
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• 2001

본 연구는 전기적 방법인 선대원통형 전극구조에서 발생되는 비열플라즈마를 이용하여 반응장치내에서의 NO의 제거율을 측정하고, 또 방전시의 방전 Image와 수평방향과 수직방향의 신호강도를 ICCD카메라를 이용하여 관측하였다. NO입자의 제거율은 NO농도가 낮을수록 높아지는 것을 확인할 수 있었으며, 수평방향의 신호강도와 수직방향의 신호강도는 NO농도가 낮을수록 큰 것을 확인할 수 있었다. 특히 방전에 의해 발생되는 비열플라즈마를 이용했을때의 교류방전시의 Image를 관측함으로써 NO입자의 방전 메카니즘을 보다 명확하게 규명하고자 하였다.

• 한국전기전자재료학회논문지
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• 제16권5호
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• pp.385-389
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• 2003

There are four main components of the CMP process: polishing pad, slurry, elastic supporter, and pad conditioner. The polishing pad is an essential component to the reproducibility of polishing uniformity in CMP process. However, the polishing pad in recently using metal CMP raised the several points of high cost caused by the increase of cycle time and the many usage of slurry. It is necessary to develop the novel polishing pad which would lead the cost reduction by the higher pad life-cycle, minimized cycle time and lower slurry usage. The characteristics of polishing pad were studied on the effects of different sets of the Polishing pad, which can be applied to metal chemical mechanical polishing process for global planarization of multilevel interconnection structure. The main purpose of this experiment is cost reduction by the increase of pad life-time, the decrease of cycle time and the lower usage of slurry through the specific hard porous structured pad design. It is confirmed that the novel polishing pad made the slurry usage decrease to 60% as well as the pad life-time increase twice with the 25% improvement of removal rate. The polishing time could be decreased and it also helped the cycle time to diminish. It can be expected that this results will help both the process throughput and the device yield to be improved.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 하계학술대회 논문집 C
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• pp.1818-1820
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• 2003

In this study, we developed friendly-environment device through various applications of pulse power system and studied research about pulse energy transfer characteristics. We have studied the mutual relation between characteristics of the load impedance and consumed power of the pulse power system. The consumed power means electrical power from the wall plug. For changing the load impedance, we could change elecrode length. As results, we can get electrical characteristics between pulse generator and load. When the pulse energy was triggered the microbes, caused waste water, they were almost removed in the waste water.

• 한국지능시스템학회논문지
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• 제16권5호
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• pp.581-586
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• 2006

본 논문에서는 무인주행 차량의 자율주행에 사용되는 자계안내시스템에서 지자계를 제거하기 위한 새로운 방법으로 Ground 검출법을 제안한다. 자계안내시스템은 도로에 일정한 간격으로 자계표식을 매설하고 차량이 자계표식으로부터 떨어진 거리를 인식하여 주행하는 방법이다. 차량이 주행 중 측면이탈거리를 알기 위해서는 지자계가 제거된 자계표식의 자계만을 이용해야 한다. 그러나 자계센서는 자계를 검출할 때 자계표식의 자계와 지자계를 함께 계측한다. 지자계는 차량의 주행방향과 경사에 따라 다르게 검출되기 때문에 자계표식의 자계와 더해질 경우 측면이탈거리를 인식하는데 오차를 발생한다. 따라서 본 논문에서는 지자계를 제거하는 새로운 방법을 제안하고, 이를 검증하기 위한 실험 장치를 구성하였다. 그리고 실험을 통하여 제안한 방법의 타당성과 유용성을 입증한다.

• 대한두개안면성형외과학회지
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• 제20권5호
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• pp.319-323
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• 2019

Cochlear implant extrusion, which is a common complication of cochlear implants, is generally repaired by a well visualized soft-tissue flap. A 61-year-old female patient with a medical history of schizophrenia who had a skin ulcer that caused cochlear implant extrusion, but that would be a stronger statement was referred to our department for removal of the implant and reconstruction of the resultant scalp defect. Accordingly, the broad defect was covered via rotation of a temporoparietal fascia flap (TPFF) using the superficial temporal artery, with the pedicle in the preauricular region as the pivot point. Coverage of TPFF was achieved with a split-thickness skin graft using the scalp as the donor site, which led to a quick recovery after the operation and satisfactory results in terms of aesthetics. This case suggests that a TPFF might be used as a flexible flap with low donor site morbidity for reconstructing cases of cochlear implant extrusion accompanied by a large full-layer scalp defect.