• 대한기계학회논문집A
• /
• 제34권12호
• /
• pp.1857-1863
• /
• 2010

본 논문에서는 탄소나노튜브 필름을 이용한 투명 압저항체의 제작 및 특성 연구를 수행하였다. 진공필터 방식으로 제작된 다양한 투과도를 가지는 탄소나노튜브 필름은 금층이 증착된 실리콘 기판위에서 사진식각 공정을 통해 패터닝이 된 후, 금층과 실리콘 기판의 약한 접착력으로 인해 실리콘 러버인 poly-dimethysiloxane (PDMS) 로 전사된다. 탄소나노튜브 필름의 압저항 특성을 분석하기 위해, 얇은 PDMS 멤브레인의 처짐에 대한 탄소나노튜브 필름의 저항 변화를 측정하여 10-20 의 개이지 팩터를 얻었으며, 인가 압력에 대한 저항 변화 실험을 수행하였다. 본 실험을 통하여 탄소나노튜브 필름은 폴리머 멤스의 다양한 응용분야에 투명한 압저항체로 사용될 수 있을 것으로 판단한다.

• 한국정밀공학회지
• /
• 제31권12호
• /
• pp.1101-1106
• /
• 2014

Hybrid manufacturing technology has been advanced to overcome limitations due to traditional fabrication methods. To fabricate a micro/nano-scale structure, various manufacturing technologies such as lithography and etching were attempted. Since these manufacturing processes are limited by their materials, temperature and features, it is necessary to develop a new three-dimensional (3D) printing method. A novel nano-scale 3D printing system was developed consisting of the Nano-Particle Deposition System (NPDS) and the Focused Ion Beam (FIB) to overcome these limitations. By repeating deposition and machining processes, it was possible to fabricate micro/nano-scale 3D structures with various metals and ceramics. Since each process works in different chambers, a transfer process is required. In this research, nanoscale 3D printing system was briefly explained and an alignment algorithm for nano-scale 3D printing system was developed. Implementing the algorithm leads to an accepted error margin of 0.5% by compensating error in rotational, horizontal, and vertical axes.

• 대한기계학회논문집A
• /
• 제36권2호
• /
• pp.173-178
• /
• 2012

최근 RFID, 유연디스플레이, 태양전지, 전자 종이 등의 소자를 프린팅 방식을 이용하여 생산하려는 연구가 활발하게 진행 되고 있다. 이런 방식이 기존의 노광기술과 식각기술에 의존하는 반도체 공정에 비해 가격 경쟁력에서 우수하기 때문이다. 특히 RFID, 유연디스플레이, 태양전지, 전자 종이 등은 유연성과 대량생산을 필요로 하기 때문에 롤투롤(roll to roll)공정과 같은 저가격화, 대형생산화에 관심이 집중되고 있다. 이 롤투롤 기술을 사용하기 위해서는 인쇄 패턴의 빠른 구현, 표면 균일도, 두께 등의 높은 인쇄 품질이 보장 되어야 한다. 본 연구는 실험계획법(Design of Experiment)을 적용하여 인자들의 주효과와 교호작용 효과를 분석하고, 롤투롤 전자인쇄 시스템에서 닙 롤의 특성에 따른 인쇄 품질의 영향과 인쇄 품질의 향상 방안을 찾기 위한 매칭기술을 제안 하였다.

• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2007년도 춘계학술대회B
• /
• pp.2171-2176
• /
• 2007

The 3-omega (3-${\omega}$) method is utilized to measure the thermal conductivity of nanofluids. A metal line heater on a silicon nitride membrane bridge structure is microfabricated by a bulk silicon etching method. Localized measurement of the thermal conductivity within the nanofluids droplet is possible by the fabricated 3-${\omega}$ sensor. Time varying AC temperature amplitudes and thermal conductivities are measured to check the stability of the nanofluids containing multi-wall carbon nanotubes (MWCNTs). Stabilities of MWCNT nanofluids prepared with different chemical treatments are compared. Acid treated MWCNT showed best dispersion stability in water while MWCNTs dispersed in water with surfactants such as Gum Arabic and Sodium dodecyl benzene sulfate showed clear sign of gravity dependence.

• 한국소성가공학회:학술대회논문집
• /
• 한국소성가공학회 2001년도 추계학술대회 논문집
• /
• pp.200-203
• /
• 2001

Micromolding methods such as micro-injection molding and micro-compression molding are most suitable for mass production of plastic micro-optics with low cost. In this study, plastic micro-optical components, such as refractive microlenses and diffractive optical elements(DOEs) with various grating patterns, were fabricated using micro-compression molding process. The mold inserts were made by ultrapricision mechanical machining and silicon etching. A micro compression molding system was designed and developed. Polymer powders were used as molded materials. Various defects found during molding were analyzed and the process was optimized experimentally by controlling the governing process parameters such as histories of mold temperature and compression pressure. Mim lenses of hemispherical shape with $250{\mu}m$ diameter were fabricated. The blazed and 4 stepped DOEs with $24{\mu}m$ pitch and $5{\mu}m$ depth were also fabricated. Optical and geometrical properties of plastic molded parts were tested by interferometric technique.

• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2001년도 춘계학술대회논문집D
• /
• pp.909-914
• /
• 2001

Fluid properties which are most commonly used to evaluate spray atomization characteristics, are important because they affect velocity and size distribution of droplets. The purpose of this study was to incorporate the significant characteristics in atomization process of industrial etching spray and how each of them affects the design of precise pressure-swirl nozzles. The experiment was carried out with different viscosity and density of fluid. The macro characteristics of liquid spray, such as the spray angle and shape were captured by PMAS and the micro characteristics of liquid spray, such as droplet size and velocity were obtained by PDA. The mean velocity and SMD of droplets were measured along axial and radial direction. It was found that the higher viscosity and density resulted in the larger SMD and the lower mean velocity of droplets.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2002년도 춘계학술대회 논문집
• /
• pp.956-959
• /
• 2002

In this work, a new non-lithographic micro-fabrication technique is presented. The motivation of this work is to overcome the demerits of the most commonly used photo-lithographic techniques. The micro-fabrication technique presented in this work is a two-step process which consists of mechanical scribing followed by chemical etching. This method has many advantages over other micro-fabrication techniques since it is simple, cost-effective, rapid, and flexible. Also, the technique can be used to obtain a metal structure which has sub-micrometer width patterns. In this paper, the concept of this method and its application to microsystem technology are described.

• 한국정밀공학회지
• /
• 제19권11호
• /
• pp.228-233
• /
• 2002

In this work, a new non-photolithographic micro-fabrication technique is presented. The motivation of this work is to overcome the demerits of the most commonly used photolithographic techniques. The micro-fabrication technique presented in this work is a two-step process which consists of mechanical scribing followed by chemical etching. This method has many advantages over other micro-fabrication techniques since it is simple, cost-effective, rapid, and flexible. Also, the technique can be used to obtain a metal structure which has sub-micrometer width patterns. In this paper, the concept of this method and its application to microsystem technology are described.

• 대한소아치과학회지
• /
• 제10권1호
• /
• pp.77-83
• /
• 1983

The purpose of this study was to observe the microleakage of a pit and fissure sealant at the tooth-restoration interface. One hundred and sixty-seven extracted permanent and deciduous teeth were used and some simple mechanical pretreatment were done before etching. The degree of microleakage was assessed by $Ca^{45}$ after 24 hours, and 2 months. The results were as follows: 1. Among total 167 teeth, 53 teeth (32%) were demonstrated the microleakage. 2. After 2 months the leakage was increased from 22 percent to 35 percent in permanent teeth, and from 32 percent to 43 percent in primary teeth. 3. The group treated by fluoride paste was demonstrated the largest leakage, 50 percent in primary teeth and 33 percent in permanent teeth. There are more leakage in primary teeth (38%) than permanent teeth (28%).

• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2003년도 춘계학술대회
• /
• pp.1069-1072
• /
• 2003

Ultraviolet-nanoimprint lithography (UV-NIL) is a promising nanoimprint method for cost-effectively defining nanometer scale structures at room temperature and low pressure. Nanostamp fabrication technology is a key technology for UV-NIL because fabricating a high resolution nanostamp is the first step for defining high resolution nanostructures in a substrate. We used quartz as an UV transparent stamp material for the UVNIL. A $5{\times}5{\times}0.09$ inch stamp was fabricated using the quartz etch process in which Cr film was used as a hard mask for transferring nanostructures into the quartz. In this paper, we describe the quartz etching process and discuss the results including SEM images.