• 한국기계가공학회지
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• 제13권6호
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• pp.30-36
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• 2014

Many different cells types have been found to be highly sensitive to mechanical force imposed by their surroundings. The cellular response to external mechanical forces has very important effects on numerous biological phenomena. In spite of its importance in biological processes, the cell adhesion force remains difficult to measure quantitatively at the cellular level. In this paper, to enhance quantitative measurements of cell adhesive interactions, a new attaching system and a method in which a glass bead can be attached to an AFM cantilever was designed and fabricated, and the degree of range displacement was controlled in the system. In an experiment, the movement of the stage in the attaching system and the attaching process were measured. The effectiveness of this system was confirmed as well in the experiment. In addition, through a commercial AFM system, the spring constant of the modified AFM probe could be measured.

• 한국기계가공학회지
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• 제12권6호
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• pp.117-124
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• 2013

Recently, the cell adhesion phenomenon that occurs in or between cells and other substances has become an important field of research in biology and biomedical engineering. Among the research, the foundational studies primarily experiment using biomedical materials (e.g. Glass Beads) attached to an AFM cantilever. For cell adhesion research, the mechanism where biomedical materials can be attached to the cantilever must be developed for this purpose; however, the mechanism remains an insufficient step. In this paper, a new stage where the Glass Bead can be attached to the cantilever is designed and fabricated;, the mm range movement in the stage is controlled using the stepping motor with a minimum displacement of $1{\mu}m$. The adhesive flow is also controlled using a PZT actuator. In addition, through the air suction, the cantilever holder can be fixed to the stage. The new stage including the bond inflows mechanism is evaluated and analyzed using theory and experiments.

• 한국전기전자재료학회논문지
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• 제19권10호
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• pp.894-900
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• 2006

This paper reports the fabrication and characterization of $32{\times}32$ thermal cantilever array for nano-scaled memory device applications. The $32{\times}32$ thermal cantilever array with integrated tip heater has been fabricated with micro-electro-mechanical systems(MEMS) technology on silicon on insulator(SOI) wafer using 9 photo masking steps. All of single-level cantilevers(1,024 bits) have a p-n junction diode in order to eliminate any electrical cross-talk between adjacent cantilevers. Nonlinear electrical characteristic of fabricated thermal cantilever shows its own thermal heating mechanism. In addition, n-channel high-voltage MOSFET device is integrated on a wafer for embedding driver circuitry.

• 한국항공우주학회지
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• 제37권2호
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• pp.175-180
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• 2009

이 논문은 폴리머 기반의 전기 분무 장치를 만들기 위하여 이온빔 장치를 통하여 초소수성으로 가공 된 polytetrafluoroethylene(PTFE) 노즐을 사용하였다. 초소수성 표면을 만들기 위하여, PTFE 표면은 Ar과 $O_2$를 이용한 이온빔 공정 장치를 사용하였다. 최적의 표면 공정 조건은 Ar과 $O_2$ 유량 및 에너지 단위를 변화 시켜 얻을 수 있었다. 공정된 노즐의 표면 특성을 분석하기 위하여 접촉각 측정을 수행하였고, 표면의 형태적 분석을 위해 scanning electron microscope(SEM) 그리고 atomic force microscope(AFM) 측정을 하였다. 초소수성으로 공정된 노즐을 사용함으로써 보다 안정적이고 반복적인 전기 분무가 가능함을 확인 하였으며, 공정 된 노즐의 성능을 평가하기 위하여 외팔보와 이온빔으로 표면 처리 된 노즐 그리고 레이져 변위센서를 이용하여 마이크로 스케일의 추력을 측정하였다.

• KSTLE International Journal
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• 제6권2호
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• pp.33-38
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• 2005

Submicron-scale patterns made of polymethyl methacrylate (PMMA) were fabricated on silicon-wafer using a capillarity-directed soft lithographic technique. Polyurethane acrylate (PUA) stamps (Master molds) were used to fabricate the patterns. Patterns with three different aspect ratios were fabricated by varying the holding time. The patterns fabricated were the negative replica of the master mold. The patterns so obtained were investigated for their adhesion and friction properties at nano-scale using AFM. Friction tests were conducted in the range of 0-80 nN. Glass (Borosilicate) balls of diameter 1.25 mm mounted on cantilever (Contact Mode type NPS) were used as tips. Further, micro-friction tests were performed using a ball-on-flat type micro-tribe tester, under reciprocating motion, using a soda lime ball (1 mm diameter) under a normal load of 3,000 mN. All experiments were conducted at ambient temperature ($24{\pm}1^{\circ}C$) and relative humidity ($45{\pm}5\%$). Results showed that the patterned samples exhibited superior tribological properties when compared to the silicon wafer and non-patterned sample (PMMA thin film) both at the nano and micro-scales, owing to their increased hydrophobicity and reduced real area of contact. In the case of patterns it was observed that their morphology (shape factor and size factor) was decisive in defining the real area of contact.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2000년도 하계학술대회 논문집
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• pp.528-531
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• 2000

Deposition of PZT with UV laser ablatio was applied for realization of thin film sensors and actuators. Deposition rate of more than 20nm/min was attained by pulsed KrF excimer laser deposition, which is fairly better than those obtained by the other methods. Perovskite phase was obtained at room temperature deposition with Fast Atom Beam(FAB) treatment and annealing. Smart MEMS(Micro electro-mechanical system) is now a suject of interest in the field of micro optical devices, micro pumps, AFM cantilever devices etc. It can be fabricated by deposition of PZT thin films and micromachining. PZT films of more than 1 micron thickness is difficult to obtain by conventional methods. This is the reason why we applied excimer laser ablation for thin film deposition. The remanent polarization Pr of 700nm PZT thin film was measured, and the relative dielectric constant was determined to about 900 and the dielectric loss tangent was also measured to be about 0.04. XRD analysis shows that, after annealing at 650 degrees C in 1 hour, the perovskite structure would be formed with some amount of pyrochlore phase, as is the case of the annealing at 750 degrees C in 1 hour.