• 한국진공학회지
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• 제19권4호
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• pp.256-264
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• 2010

본 논문에서는 고진공용 터보분자펌프의 비접촉 고속회전을 위한 자기베어링 시스템의 디지털 제어시스템의 설계에 대하여 소개하였으며, 실례로 800 l/s급의 고진공 펌프에 대하여 축 유연모드의 후방향 위험속도를 넘는 최대 40,000 rpm까지의 회전실험 결과를 나타내었다. 제안된 제어시스템은 기본적으로 PID 기반의 직접궤환 제어기와 자이로스코픽 모멘트 효과를 제어하기 위한 교차궤환기, 유연모우드 감쇄를 위한 리드필터와 동기진동 저감을 위한 노치필터 등으로 구성되어 있으며, 이러한 제어기는 자기부상형 터보분자펌프 외에 고속 플라이휠과 같은 자기베어링에 적용될 수 있다.

• 한국진공학회지
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• 제15권1호
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• pp.57-63
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• 2006

진공 인라인 실장기술에 의해 제조된 프라즈마 디스플레이 패널(PDP)의 전기적 및 광학적 특성을 분석하였다. 분석결과, 초기 진공도가 증가함에 따라 발광효율이 증가함을 확인하였다 즉, $1\times10^{-3}$ torr의 진공도인 경우에 대해서는, 동작전압이 235 V(방전가스의 압력을 400 Torr일 경우) 이고 발광효율이 0.8 1n,/W(180 V의 유지전압에 대해) 인데 반해 초기 진공도가 $1\times10^4 torr$일 경우에 대해서는, 동작전압이 215V로 낮아졌고 발광효율은 2.5lm/W로 향상되었음을 확인하였다. 더불어, 진공 인-라인 실장 방법을 이용하여 tip-]ess형 PDP 동작 패널을 성공적으로 제조할 수 있었다.

• 한국진공학회지
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• 제2권2호
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• pp.139-144
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• 1993

동적교정방법을 이용하여 $10^{-7}~10^{-10}$torr 영역에서 교정 가능한 초고진공 표준기를 제작하였다. $10^{-6}~10^{-9}$torr L/s 영역의 극미세 유량은 고진공 표준기에 porous plug를 연결하여 발생 제어시켰으며 일정한 배기속도를 유지함이 알려져 있는 refrigerator type cryopump를 이용하여 $3{\times}10^{-11}$torr의 base pressure를 얻을 수 있었다. 이 초고진공 표준기를 이용하여 두 개의 extractor gauge와 자체 제작한 nude 이온게이지들을 교정하고 그 직선성 및 재현도를 살펴보았다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2016년도 제50회 동계 정기학술대회 초록집
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• pp.363.2-363.2
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• 2016

Stretchable strain sensors are becoming essential in diverse future applications, such as human motion detection, soft robotics, and various biomedical devices. One of the well-known approaches for fabricating stretchable strain sensors is to embed conductive nanomaterials such as metal nanowires/nanoparticles, graphene, conducting polymer and carbon nanotubes (CNTs) within an elastomeric substrate. Among various conducting nanomaterials, CNTs have been considered as important and promising candidate materials for stretchable strain sensors owing to their high electrical conductivity and excellent mechanical properties. In the past decades, CNT-based strain sensors with high stretchability or sensitivity have been developed. However, CNT-based strain sensors which show both high stretchability and sensitivity have not been reported. Herein, highly stretchable and sensitive strain sensors were fabricated by integrating single-walled carbon nanotubes (SWNTs) and nylon textiles via vacuum-assisted spray-layer-by-layer process. Our strain sensors had high sensitivity with 100 % tensile strain (gauge factor ~ 100). Cyclic tests confirmed that our strain sensors showed very robust and reliable characteristic. Moreover, our SWNTs-based strain sensors were easily and successfully integrated on human finger and knee to detect bending and walking motion. Our approach presented here might be route to preparing highly stretchable and sensitive strain sensors with providing new opportunity to realize practical wearable devices.

• Membrane and Water Treatment
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• 제9권1호
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• pp.53-62
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• 2018

In this study, vacuum membrane distillation (VMD) was used to treat high-salinity wastewater (concentration about 17%) discharged by chlor-alkali plant after resin regeneration. The feasibility of VMD for the treatment of real saline wastewater by using Polyvinylidene fluoride (PVDF) microporous plate membrane with a pore diameter of $0.2{\mu}m$ was investigated. The effects of critical operating parameters such as feed temperature, velocity, vacuum degree and concentration on the permeate water flux were analyzed. Numerical simulation was used to predict the flux and the obtained results were in good agreement with the experimental data. The results showed that an increase in the operating conditions could greatly promote the permeate water flux which in turn decreased with an increase in the concentration. When the concentration varied from 17 to 25%, the permeate water flux dropped marginally with time indicating that the concentration was not sensitive to the decrease in permeate water flux. The permeate water flux decreased sharply until zero due to the membrane fouling resistance as the concentration varied from 25 to 26%. However, the conductivity of the produced water was well maintained and the average value was measured to be $4.98{\mu}s/cm$. Furthermore, a salt rejection of more than 99.99% was achieved. Overall, the outcome of this investigation clearly indicates that VMD has the potential for treating high-salinity wastewater.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2007년도 추계학술대회 논문집
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• pp.314-317
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• 2007

Domestic automobile industries have been focusing their effort on development of exhaust manifolds using high temperature stainless steel. Exhaust manifolds fabricated with stainless steels can be categorized into tubular and cast ones. The former is usually manufactured by forming and welding process and the latter by vacuum casting process. In the present study, high temperature mechanical properties of 5 austenitic stainless steels, one was sand cast and the others vacuum cast, were investigated by performing a series of high temperature tensile tests and high temperature low cycle fatigue tests.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제45회 하계 정기학술대회 초록집
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• pp.184.1-184.1
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• 2013

It is generally known that electron beam has sterilization effects and can activate plant germination and growth. Compared to electron beam, electrical pulse has not been frequently studied with respect to the biological application. In this study, we have analyzed the effects of high voltage pulse on seed germination and growth using various plant species. We have used the high voltage generator for examining seed's responses to the high voltage pulse. The operating voltage and currents of the generator are about 300 kV and 30 kA, respectively. Pulse width is 60 ns. High voltage pulse has slightly activated germination and growth of radish during early stage. Various levels of germination and growth are observed in different plant species after treated with high voltage pulse.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2008년도 추계학술대회 논문집
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• pp.611-612
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• 2008

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2008년도 추계학술대회 논문집
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• pp.493-494
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• 2008

• 한국진공학회:학술대회논문집
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• 한국진공학회 2007년도 제32회 학술대회 초록집
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• pp.185-185
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• 2007