• 대한기계학회논문집A
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• 제29권12권
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• pp.1645-1652
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• 2005

Pick-and-place systems using suction cups have been being widely used and continuously developed in production automation. There are, however, some drawbacks in constructing such systems. One of them is that it generates high level noise due to air compressors. And the system must have complex constitutions of mechanical component such as air compressors, air tubes, air valves, etc. Moreover, it needs continuous air supply to maintain vacuum in suction cups. If there is a failure in any suction cup, the total suction system may fail owing to air leakage. To overcome these drawbacks, we propose PMS (Permanent Magnet Suction) mechanism which has permanent magnets for vacuuming suction cups with no air compressor. The basic concept of PMS mechanism is to rotate permanent magnets with fixed angle. Simple rotation of permanent magnets changes the direction of the magnetic force applied at the suction cups. Since each suction cup has no direct connection with any of the others, the air leakage at one suction cup is not critical. The proposed suction mechanism was designed and fabricated. With some experiments, the feasibility and performance of the PMS mechanism was shown. The strong points of the PMS mechanism are in its simple structure, generating low noise, high energy efficiency, and no need of continuous energy supply.

• Journal of Korean Vacuum Science & Technology
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• 제4권1호
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• pp.1-5
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• 2000

The C 1s photoelectron energy loss spectra of tris (8-hydroxy-quinoline) aluminum (Alq$_3$) and N,N'-diphenyl-N,N'-bis (3-methyl phenyl)-1,1'-bi-phenyl-4,4'-diamine (TPD) thin films have been investigated. Two major loss structures, namely the plasmon dominated loss lines and shake-up satellites, have been observed. The shake-up spectrum of the C 1s photoelectron line is directly related to the $\pi$-$\pi$$\^$*/ energy gap of the molecule which plays an important role in organic electroluminescent materials. The molecular orbitals of Alq$_3$ and TPD and their major components, quinolime and benzene, have been calculated with the AMI semi-empirical method. The amount of the plasma-dominated loss of Alq$_3$ and TPD, which has to do with the delocalization of electrons through the molecule, was about 24 eV, alike in both cases. The main peak of the C 1s shake-up spectrum of Alq$_3$ and TPD, however, was 5.2 eV and 6.8 eV respectively. It was found that the main shake-up peak reflects more the local $\pi$\longrightarrow$\pi$$\^$*/ transition of quinoline and benzene component rather than the excitation of the whole molecule of Alq$_3$ and TPD. The C 1s shake-up spectra, however, revealed some correlation with the optical energy gap of the organic eletroluminescent materials.

• 한국진공학회지
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• 제16권3호
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• pp.227-230
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• 2007

리튬이온 제조공정에서 전해질 주입 후 반드시 거쳐야 하는 숙성공정은 일반적으로 별로 중요하게 다루어 지지 않고 있다. 왜냐하면 전지 숙성공정이 전지성능에 영향을 주는 인자에 대하여 그다지 깊이 있게 연구가 되어있지 않기 때문이다. 하지만 숙성공정 중에 나타나는 OCV 변화는 전해질 내에 포함되어 있는 성분이 전극으로 전기화학적 흡착되어 나타나는 현상으로 SEI 피막 형성에 매우 중요한 역할을 하게 된다. 이에 본 연구에서는 숙성기간 중에 변하게 되는 OCV와 SEI피막의 관계, 그리고 전지성능과의 연계에 대하여 깊이 있게 논의하고자 한다.

• 한국진공학회지
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• 제6권4호
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• pp.321-325
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• 1997

LCD용 칼라 필터를 제작하는 방법으로 감광성 고분자(photosensitive polymer)에 광 리소그라피(photolithography)기술이 많이 이용되어지고 있다. 이로 인해 감광성 고분자 표 면의 물리적, 화학적 성질이 변하게 되는데, 이는 후속 공정인 플라즈마 식각이나 ITO 전극 의 증착 등에도 많은 영향을 주므로, 각 공정에 따른 이들 고분자의 표면 연구는 매우 중요 하다. 본 논문에서는 blue 칼라 필터의 고분자 표면에 대한 연구를 SIMS와 XPS를 이용하 여 수행하였으며, 표면의 거칠기 변화를 AFM을 통해 관찰하였다. SIMS와 XPS결과로부터 초기 공정인 blue 칼라 필터를 스핀 코팅하고 pre bake한 상태에서는 주로 칼라 필터의 주 성분인 단량체와 결합제의 고분자 물질이 표면에 드러나 있다가, 노광 과정을 거치고 post bake한 시료에서는 색깔을 내는 안료 성분이 표면에 드러남을 확인하였고, AFM을 통해서 는 post bake후에 표면에 더 거칠어 짐을 관찰하였다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제44회 동계 정기학술대회 초록집
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• pp.696-696
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• 2013

Solid Oxide Fuel Cells (SOFCs) have been gaining academic/industrial attention due to the unique high efficiency and minimized pollution emission. SOFCs are an electrochemical system composed of dissimilar materials which operates at relatively high temperatures ranging from 800 to 1000oC. The cell performance is critically dependent on the inherent properties and integration processing of the constituents, a cathode, an electrolyte, an anode, and an interconnect in addition to the sealing materials. In particular, the gas transport, ion transport, and by-product removal also affect the cell performance, in terms of open cell voltages, and cell powers. In particular, the polarization of cathode materials is one of the main sources which affects the overall function in SOFCs. Up to now, there have been studies on the materials design and microstructure design of the component materials. The current work reports the effect of thin film processing on cathode polarization in solid oxide fuel cells. The polarization issues are discussed in terms of dc- and ac-based electrical characterizations. The potential of thin film processing to the applicability to SOFCs is discussed.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2010년도 제39회 하계학술대회 초록집
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• pp.293-293
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• 2010

Carbon nanotubes (CNTs) have attracted considerable attention as possible routes to device miniaturization due to their excellent mechanical, thermal, and electronic properties. These properties show great potential for devices such as field emission displays, CNT based transistors, and bio-sensors. The metals such as nickel, cobalt, gold, iron, platinum, and palladium are used as the catalysts for the CNT growth. In this study, diamond-like carbon (DLC) was used for CNT growth as a nonmetallic catalyst layer. DLC films were deposited by a radio frequency (RF) plasma-enhanced chemical vapor deposition (RF-PECVD) method with a mixture of methane and hydrogen gases. CNTs were synthesized by a hot filament plasma-enhanced chemical vapor deposition (HF-PECVD) method with ammonia (NH3) as a pretreatment gas and acetylene (C2H2) as a carbon source gas. The grown CNTs and the pretreated DLC filmswere observed using field emission scanning electron microscopy (FE-SEM) measurement, and the structure of the grown CNTs was analyzed by high resolution transmission scanning electron microscopy (HR-TEM). Also, using energy dispersive spectroscopy (EDS) measurement, we confirmed that only the carbon component remained on the substrate.

• 한국진공학회지
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• 제12권3호
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• pp.182-192
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• 2003

밀리미터파 대역용 고속 PHEMT 소자 제작 및 개발을 위하여 다층 리지스트 및 다원자 기판 구조에서 전자빔 리소그래피 공정을 분석할 수 있는 새로운 몬테 카를로 시뮬레이션 모델을 개발하였다. 전자빔에 의해 다층 다원자 타겟 기판 구조에 전이되는 에너지를 정확하고 효율적으로 계산하기 위하여 다층 리지스트 및 다층 다원자 기판 구조에서 시뮬레이션 가능하도록 새로이 모델링하였다. 본 논문에서 제안 개발된 모델을 사용하여 PHEMT 소자의 전자빔 리소그래피에 의한 T-게이트 형성 공정을 시뮬레이션하고 SEM측정 결과와 비교 분석하여 타당성을 검증하였다.

• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 2005년도 추계학술발표대회 개요집
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• pp.195-197
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• 2005

An intermediate heat exchanger(IHX) is a key component in a next-generation VHTR with process heat applications such as hydrogen production and also for an indirect gas turbine system. Therefore, high temperature brazing with nickel-based filler metal(MBF-15) was carried out to study the joining characteristic(microstucture, joining strength) of nickel-based superalloy(Haynes 230) by vacuum brazing. The experimental brazing was carried out at the brazing process, an applied pressure of about 0.74Mpa and the three kinds of brazing temperatures were 1100, 1150, and $1190^{\circ}C$ with holding time 5 minute. It's joining phenomena were analyzed by optical microscopy and scanning electron microscopy with EPMA. The results of microstructure in the centre-line region of a joint brazed with MBF-15 show a typical ternary eutectic of v-nickel, nickel boride and chromium boride.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제42회 동계 정기 학술대회 초록집
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• pp.275-275
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• 2012

The relative composition of $Cu(InGa)Se_2$ solar cells is one of the most important measurement issues. However, quantitative analysis of multi-component alloy films is difficult by surface analysis methods due to severe matrix effect. In this study, quantitative depth profiling analysis of CIGS films was investigated by secondary ion mass spectrometry (SIMS). The compositions were measured by SIMS using the alloy reference relative sensitivity factors derived from the certified compositions and the total counting numbers of each element. The compositions measured by SIMS were linearly proportional to those by inductively coupled plasma-mass spectrometry (ICP-MS) using isotope dilution method. In this study, the quantification measured by ICP-MS method is compared with the composition calculated by SIMS depth profiles with AR-RSFs obtained from the reference. The SIMS depth profile of CIGS thin films according to the manufacturing condition was converted into compositional depth profile.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2011년도 제41회 하계 정기 학술대회 초록집
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• pp.313-313
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• 2011

최근, 산화물 반도체를 통한 나노선 연구가 활발히 진행되고 있다. 1차원 나노선은 넓은 표면적을 가지며 다양한 특성을 지녀 미래 nanodevice로의 중요한 building block 소자로의 활용이 가능하다. 본 연구에서는 이종의 나노선을 합성하여 hierarchical nanojunction structure를 제작, 특성을 확인하였다. 이러한 구조는 나노선이 가지는 넓은 표면적의 특성과 동시에, multi-component fuctional nanodevice를 구현하는데에 적합한 구조이다. 본 연구는 텅스텐 기판 위에 고온의 열증착 방식을 이용하여 텅스텐 산화물 나노선을 제작시켜 그 위에 저온의 수열합성을 통한 산화아연 나노선을 제작한 후 향상된 field emission emitter로서의 특성을 살펴보았다. 합성된 텅스텐 산화물 나노선은 quasi-allign된 구조를 가지며, 이러한 구조 위에 ZnO를 스퍼터링하여 seed layer를 형성시키고, 암모니아수와 아연염을 이용한 수열합성법을 통하여 합성된 나노선 위에 nanobranch의 산화아연 나노선을 형성하였다. 이러한 성장특성은 SEM, TEM을 통하여 확인하였고 각각의 특성과 계면을 살펴보았다. 또한 이러한 구조를 이용하여 전계방출특성을 확인하였는데, 약 5.7 eV의 일함수를 갖는 텅스텐 산화물 나노선 위에 더 작은 값의 일함수를 갖는 산화아연 나노선을 합성하여 전계방출특성을 보았으며, 더 향상된 결과를 얻을 수 있었다. 또한 산화아연의 합성방법에 따른 전계방출 특성의 차이도 비교하였다.