• 한국가스학회지
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• 제8권3호
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• pp.24-30
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• 2004

본 연구에서는 개선된 view cell 실험 장치를 통하여 가스 하이드레이트 생성 과정을 관찰하고 이의 동특성을 고찰하였다. 순수한 물과 촉진제로 음이온계 계면활성제를 미량 첨가한 물에 천연가스를 넣어 가스 하이드레이트를 생성 과정을 관찰하였다. 본 실험에서 사용한 276.65 K, 6 MPa 조건 상태에서는 충분한 지체 지연 시간이후 물에 순간 교반을 줌으로써 형성자 생성을 쉽게 유도할 수 있었다. 가스 하이드레이트 필름의 생성은 정적상태에서 가스와 접촉된 물의 표면에 생성되었다. 이는 육안으로 구분하기 어려운 매우 얇은 막이 수초 안에 물의 표면 전체를 덮는 선행과정과 이후 다시 육안관찰이 쉬운 필름층이 재생성되었다. 순수한 물에는 짧고 굵은 섬유 다발의 형태로 끝 부분이 둥글게 말려서 결정이 형성된 모습인 반면 촉진제를 넣은 경우 작은 섬유 다발 형태로 길게 생성되었고 다른 다발과 접촉되어 엉킨 결정 상상을 보였다.

• 한국산학기술학회논문지
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• 제16권5호
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• pp.2979-2984
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• 2015

본 연구에서는 발포제를 이용하여 형성된 기공을 확대하는 방식의 공정으로써, 선택적 하이브리드 구조의 폴리머 필름의 제작을 위한 새로운 발포기술을 제시하였다. 기존의 발포제만을 이용한 폐쇄형 기공보다 큰 기공을 형성하기 위해서 PP에 발포제와 구리분말(Copper powder)을 혼합하여 만든 필름 내부에 355nm파장의 UV 펄스레이저를 이용하여 LAMO(Laser Aided Micro pore Opening) 공정 방식을 통한 기공의 크기를 확장하는 실험을 진행하였다. 그 결과 발포공정만 수행된 기공의 크기보다 추가적인 LAMO 공정을 통해 형성된 기공의 크기가 훨씬 더 크게 관찰되었다. 본 실험의 결과를 통해 LAMO 공정에 의한 기공의 특성과의 상관관계를 파악할 수 있었으며, 기존의 UV laser를 이용하여 원하는 부위에 선택적으로 폐쇄형 기공을 형성하는 것 이상으로 기공의 크기를 제어하는 방안을 제시하고자 한다.

• Nuclear Engineering and Technology
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• 제53권4호
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• pp.1297-1303
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• 2021

Most thickness measurement techniques using X-ray radiation are unsuitable in field processes involving fast-moving organic films. Herein, we propose a Compton scattering X-ray radiation method, which probes the light elements in organic materials, and a new simple, non-destructive, and non-contact calibration-free real-time film thickness measurement technique by setting up a bench-top X-ray thickness measurement system simulating a field process dealing with thin flexible organic films. The use of X-ray fluorescence and Compton scattering X-ray radiation reflectance signals from films in close contact with a roller produced accurate thickness measurements. In a high-thickness range, the contribution of X-ray fluorescence is negligible, whereas that of Compton scattering is negligible in a low-thickness range. X-ray fluorescence and Compton scattering show good correlations with the organic film thickness (R² = 0.997 and 0.999 for X-ray fluorescence and Compton scattering, respectively, in the thickness range 0-0.5 mm). Although the sensitivity of X-ray fluorescence is approximately 4.6 times higher than that of Compton scattering, Compton scattering signals are useful for thick films (e.g., thicker than ca. 1-5 mm under our present experiment conditions). Thus, successful calibration-free thickness monitoring is possible for fast-moving films, as demonstrated in our experiments.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2009년도 추계학술대회 논문집
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• pp.124-124
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• 2009

We observed the changes of crystal structure of Rubrene (5,6,11,12-tetraphenylnaphthacene) polycrystal thin films at various in situ substrate temperature and process by scanning electron microscope(SEM), x-ray diffraction (XRD) and near-field microwave microprobe (NFMM). Amorphous rubrene thin film was initially obtained on 200 nm thick $SiO_2/Si$ substrate at 35 $^{\circ}C$ in a vacuum evaporation but in situ long time postannealing at the temperature 80 $^{\circ}C$ transformed the amorphous phase into crystalline. Four heating conditions are followed : (a) preheating (b) annealing (c) preheating, annealing (d) preheating, cooling(35 $^{\circ}C$), annealing. We have obtained the largest polycrystal disk in sample (c). But the highest crytallity and conductivity of the rubrene thin films were obtained in sample (d).

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2002년도 ITC-CSCC -1
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• pp.22-25
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• 2002

The Mass production of ceramic heater has encountered with the estimation for the proper parameters of the printing conditions. This paper presents a method to estimate the squeegee pressure. It uses resistance distribution from the trial run with approximate squeegee pressure which comes from statistical process control (SPC). Then, the resistance distribution and its total resistance are input to the backpropagation neural networks that can recognize resistance's distribution patterns. The value of output network derived from the input value can identify to the appropriate squeegee pressure. The experimental results are demonstrated In ensure the efficiency and the reliability of this method with the accuracy 96.75 percent. Indeed, embedded on this method will aid us to reduce the loss from the normal mass production.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 하계학술대회 논문집 Vol.3 No.2
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• pp.553-555
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• 2002

We were fabricated of rf power resisotor on AlN substrates by thick film process. The characteristics of capacitance and microwave are measured by digital LCR meter and Network analyzer(HP8532D). The results are shown that capacitances are slight greater and microwave characteristics are good values.

• 한국레이저가공학회지
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• 제3권2호
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• pp.25-33
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• 2000

One of perspective direction of microfabrication is direct laser writing technology that allows to create metal, semiconductive and dielectric micropatterns on substrate surface. In this work, a two step method, the combination of seed forming process, in which metallic Al seed was selectively generated on AlN ceramic substrate by direct writing technique using a pulsed Nd : YAG laser and subsequent electroless Ni plating on the activated Al seed, was presented. The effects of laser parameters such as pulse energy, scanning speed and pulse frequency on shape of Alseed and conductor line after electroless Ni plating were investigated. The nature of the laser activated surface is analyzed from XPS data. The line width of this metallic Al and Ni is analyzed using SEM. As a results, Al seed line with 24㎛ width and 100㎛ isolated line space is obtained. Finally, laser direct writing can be applied in the field between thin and thick film technique in electronic industry.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2000년도 춘계학술대회논문집
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• pp.1521-1527
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• 2000

A micromirror actuated by piezoelectric unimorph cantilevers is proposed as a tine-tracking device for high-density optical data storage. Bending motions of the metal/PZT/metal unimorphs translate an integrated micromirror along the out-of-plane vertical direction. The micromirror alters the optical path of the incident laser beam and linearly steers the reflected laser beam by its out-of-plane parallel actuation. Numerical analysis shows that the actuated micromirror can satisfy the tracking speed imposed by the requirement on the access time for the high-density optical data storage up to few tens Gbitlin2 owing to the light mass of the micromirror. In this paper, preliminary characteristics of the micro-machined PZT actuated micromirror (PAM) are reported. Only a 360 nm-thick PZT film deposited by sol-gel process shows both good electrical and mechanical characteristics for the fine-tracking actuator. The micromirror can be easily actuated up to several micrometers under low voltage operation condition well below 10 volts.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 추계학술대회 논문집 Vol.14 No.1
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• pp.81-84
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• 2001

The effect of silver oxide (14 wt.%) addition to YBCO compounds and electrophoretic deposition of composite particles prepared by solid phase reaction have been investigated. The results were compared with those for as-processed samples with YBCO films on Ag wire substrate. Our experiments show that the adhesion, microstructure changes, superconducting properties of these films is sensitive to the silver content and sintering conditions. Adding a small amount of PEG tends to remove cracks in the YBCO and (YBCO + Ag) films, which develop during the heating process. An attempt has been made to explain the experimental observations regarding variation of critical current density with the YBCO and (YBCO + Ag) films.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1994년도 추계학술대회 논문집
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• pp.206-209
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• 1994

This paper has been researched bondability of electronic devices, such as lead frame and thick film of Ag/Pd on an alumina substrate by different heat sources. To obtain the bonds with high quality, it is very important to control both the thermal distribution of the bonds and it stability, because electronics components is consist of different materials. Therefore, this paper clarifies not only heat mechanism of micro parallel gap resistance bonding method and pulse heat tip bonding method but also investigates selection of heat sources with micro-electronic materials for bonding. Finally, it is realzed fluxless bonding process with filler metal such as plating layers.