• 폴리머
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• 제26권5호
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• pp.634-643
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• 2002

고분자 주사슬에 벤젠과 sulfonyloxvimide moiety를 가지고 있는 polyamic acid 초박막을 LB 기법을 이용하여 제조한 다음 200 $^{\circ}C$에서 1시간 동안 열처리에 의해 감광성 폴리이미드 LB 필름을 얻었다. Polyamic acid는 THF-pyridine 공용매를 가지고 축중합에 의해 합성하였다. 모든 단량체와 고분자는 원소분석, FT-IR, $^1$H-NMR의 분광학적 측정을 통해 정량 정성분석을 행하였다. UV lithography 방법을 사용하여 금 기판 위에 제조한 감광성 폴리이미드 LB 필름의 마이크로 어레이 패턴을 제조하였다. 형성된 마이크로 어레이 패턴을 따라 두 가지의 자기조립 방법으로 단백질 cytochrome c 단분자 막을 고정화시켰다. 자기조립된 cytochrome c 단분자 막의 물리ㆍ전기 화학적 특성은 cyclic voltammetry와 AFM을 통해 조사하였으며 생물전자소자로의 응용 가능성에 대해서도 검토하였다.

• Composites Research
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• 제21권1호
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• pp.40-45
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• 2008

자동차용 유압브레이크 고무호스 어셈블리 제품은 자동차에 장착되어 실제로 사용 중에 가압, 굽힘, 비틀림, 열하중 등의 복합적인 스트레스를 받는다. 고무호스의 재질은 EPDM(ethylene-propylene diene monomer)고무와 PVA(polyvinyl acetate)섬유 보강층 그리고 중간고무로 NR(natural rubber)고무가 사용되고 있다. 고무호스 어셈블리 제품의 내구성과 파괴 메커니즘을 조사하기 위해 굽힘과 비틀림의 반복하중 사이클 수가 10만, 20만, 30만, 40만, 최종파열 사이클 수까지 되도록 시험하였다. 유압브레이크 고무호스의 초기크랙 발생을 알아보기 위해 제품 시험편을 다이아몬드 휠커터를 이용하여 수직 절단하여 폴리싱한 후 광학현미경과 주사형 전자현미경(SEM)으로 단면을 관찰하였다. 40만 사이클의 피로하중을 받은 시험편을 보면 외면고무와 PVA섬유 사이의 계면을 따라 길이 1mm의 층간분리가 일어났으며, 이러한 손상은 외면고무의 표피층으로 균열을 진전시켜 고무호스를 최종적으로 찢어지게 하는 것이다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2016년도 제50회 동계 정기학술대회 초록집
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• pp.96-96
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• 2016

Nanotechnology mostly employs nano-materials and nano-structures with distinctive properties based on their size, structure, and composition. It is quite difficult to produce nano-materials and nano-structures with identical sizes, structures, and compositions in large quantities, because of spatiotemporal fluctuation of production processes. In other words, fluctuation is the bottleneck in nanotechnology. We propose three strategies to suppress such fluctuations: employing 1) difference between linear and nonlinear phenomena, 2) difference in time constants, and 3) nucleation as a bottleneck phenomenon. We are also developing nano- and micro-scale guided assembly using plasmas as a plasma nanofabrication.1-5) We manipulate nano- and micro-objects using electrostatic, electromagnetic, ion drag, neutral drag, and optical forces. The accuracy of positioning the objects depends on fluctuation of position and energy of an object in plasmas. Here we evaluate such fluctuations and discuss the mechanism behind them. We conducted in-situ evaluation of local plasma potential fluctuation using tracking analysis of fine particles (=objects) in plasmas. Experiments were carried out with a radio frequency low-pressure plasma reactor, where we set two quartz windows at the top and bottom of the reactor. Ar plasmas were generated at 200 Pa by applying 13.56MHz, 450V peak-to-peak voltage. The injected fine particles were monodisperse methyl methacrylate-polymer spheres of $10{\mu}m$ in diameter. Fine particles were injected into the reactor and were suspended around the plasma/sheath boundary near the powered electrode. We observed binary collision of fine particles with a high-speed camera. The frame rate was 1000-10000 fps. Time evolution of their distance from the center of mass was measured by tracking analysis of the two particles. Kinetic energy during the collision was obtained from the result. Potential energy formed between the two particles was deduced by assuming the potential energy plus the kinetic energy is constant. The interaction potential is fluctuated during the collision. Maximum amplitude of the fluctuation is 25eV, and the average is 8eV. The fluctuation can be caused by neutral molecule collisions, ion collisions, and fluctuation of electrostatic force. Among theses possible causes, fluctuation of electrostatic force may be main one, because the fine particle has a large negative charge of -17000e and the corresponding electrostatic force is large compared to other forces.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2002년도 금형가공 심포지엄
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• pp.285-291
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• 2002

The shearing process for the sheet metal is normally used in the precision elements such as a frame of TFT-LCD or lead frame of If chips. In these precision elements, the burr formation prevents the system assembly and needs the additional burr removing process. In this paper, we developed the small size NC punching system which has an aligning kinematics between the rectangular shaped punch and die. The punch is driven by an ai cylinder and the sheet metal is moving on the X-Y table system which is driven by two stewing motors. The microprocessor control the whole system and communicate with the monitoring PC by RS232C serial communication protocol. The graphic user interface program in PC monitors nil control the punching system. The cross shaped joint hinge supports the punching die and positioned by two differential screws, whose are installed in perpendicular directions. The aligning between the punch and die is performed using the sheets of half thickness(0.1mm Brass) of the real process for the frame of the TFT-LCD. Using half thickness Brass, the burr formation is magnified and we can decide the aligning direction more easily then using the real thickness(0.2mm) Aluminum. In this paper, the aligning results are measured manually using the SEM photographs and we hope to make the automated aligning procedures using some kinds of image processing techniques.

• 한국항공우주학회지
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• 제30권6호
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• pp.1-6
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• 2002

마이크로 연소실을 장착한 MAV 추진 장치용 단기통 MEMS 엔진을 제작하였다. 본연구에서는 MEMS 크기의 왕복운동 내연기관의 타당성을 검증하고 실용화를 위한 설계 및 가공데이터를 축적하고자 하였다. 엔진 블록은 가공의 정밀도와 내열성등을 고려하여 감광유리 웨이퍼를 사용하였으며, 점화 전극은 베이스 플레이트 위에 니켈 도금으로 제작하였다. 감광유리판은 등방성 에칭의 특성이 탁월하여 마이크로 엔진의 실린더와 피스톤과 같이 비교적 깊은 식각이 가능함을 확인하였다. 전체 엔진은 세 개의 별도 가공된 레이어를 접착하여 조립한다. 본연구의 엔진 연소실은 깊이는 1mn, 폭 2mn이며, 피스턴은 수소-공기 예 혼합 가스의 연소압력에 의하여 구동된다. 가공된 엔진의 연소실험을 통하여, 점화, 화염전파 및 피스턴 구동을 확인하였으며, 실용화를 위한 연구가 요구되고 있다.

• 한국진공학회지
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• 제19권2호
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• pp.81-90
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• 2010

층과 층 사이의 정전기적인력, 수소결합 또는 공유결합을 이용하여 층당 두께를 수 옹스트롱에서부터 수십 나노미터까지 제조할 수 있으며 박막의 표면 형태를 흡착시키고자 하는 물질 및 박막 후처리 공정을 통해 제어할 수 있으며 더 나아가, 삽입하는 물질의 특성에 따라 박막의 기능성을 집적화 및 다양화시킬 수 있다. 본 연구에서는 이러한 층상자기조립방법의 특성을 이용하여 반사방지막, 초소수성 필름 및 전기화학센서로의 응용가능성을 제시하였다. 반사방지막의 경우, 구형의 블록공중합체를 유리기판 위에 다층박막으로 적층시킴으로써 박막 굴절률을 1.25까지 감소시켰고 이를 통해 약 99.5%의 빛 투과도를 달성할 수 있었다. 더 나아가 바이오물질인 엔자임을 다층박막에 삽입시킬 경우, 활성 산소를 분해시키는 전기화학센서로의 제조가 가능함을 보인다. 본 연구는 본인이 이미 발표한 논문(J. Am. Chem. Soc. 128, 9935 (2006); Adv. Mater. 19, 4364 (2007); Electro. Mater. Lett. 3, 163 (2007))들을 정리하여 층상자기조립법에 관해 소개하는 논문이다.

• Fisheries and Aquatic Sciences
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• 제5권1호
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• pp.36-42
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• 2002

Microarrayer is used to make DNA chip and microarray that contain hundreds to thousands of immobilized DNA probes on surface of a microscope slide. This paper shows the develop-ment results for a printing type of microarrayer. It realizes a typical, low-cost and efficient microarrayer for generating low density micro array. The microarrayer is developed by using a prependicular type robot with three axes. It is composed of a computer-controlled three-axes robot and a pen tip assembly. The key component of the arrayer is the print-head containing the tips to immobilize cDNA, genomic DNA or similar biological material on glass surface. The robot is designed to automatically collect probes from two 96-well plates with up to 12 pens at the same time. To prove the performance of the developed microarrayer, we use the general water types of inks such as black, blue and red. The inks are distributed at proper positions of 96 well plates and the three color inks are immobilized on the slide glass under the operation procedure. As the result of the test, we can see that it has sufficient performance for the production of low integrated DNA chip consisted of 96 spots within $1cm^2$ area.

• 융복합기술연구소 논문집
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• 제1권2호
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• pp.6-15
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• 2011

This paper reports the design and fabrication of a micro-electro-mechanical-system(MEMS)-based electrostatic angular microactuator for a dual-stage servo. The proposed actuator employs a novel electrode pattern named "skewed electrode array(SEA)" scheme. It is shown that SEA has better linearity than a parallel plate type actuator and stronger force than a comb-drive based actuator. The moving and the fixed electrodes are arranged to make the driving force perpendicular to the rotating moment of arm. By changing the electrode overlap length, the magnitude of electrostatic force and stable displacement will be changed. In order to optimize the design, an electrostatic FE analysis was carried out and an empirical force model was established for SEA. A new assembly method which will allow the active electrodes to be located beneath the slider was developed. The active electrodes are connected by inner and outer rings lifted on the base substrate, and the inner and outer rings are connected to platform on which the slider locates. Electrostatic force between active electrodes and platform can be used for exiting out of plane modes, so this provides the possibility of the flying height control. A microactuator that can position the pico-slider over ${\pm}0.5{\mu}m$ using under 20 volts for a 2 kHz fine-tracking servo was designed and fabricated using SoG process.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2015년도 제49회 하계 정기학술대회 초록집
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• pp.75-75
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• 2015

Strong interactions between electromagnetic radiation and electrons at metallic interfaces or in metallic nanostructures lead to resonant oscillations called surface plasmon resonance with fascinating properties: light confinement in subwavelength dimensions and enhancement of optical near fields, just to name a few [1,2]. By utilizing the properties enabled by geometry dependent localization of surface plasmons, metal photonics or plasmonics offers a promise of enabling novel photonic components and systems for integrated photonics or sensing applications [3-5]. The versatility of the nanoplasmonic platform is described in this talk on three folds: our findings on an enhanced ultracompact photodetector based on nanoridge plasmonics for photonic integrated circuit applications [3], a colorimetric sensing of miRNA based on a nanoplasmonic core-satellite assembly for label-free and on-chip sensing applications [4], and a controlled fabrication of plasmonic nanostructures on a flexible substrate based on a transfer printing process for ultra-sensitive and noise free flexible bio-sensing applications [5]. For integrated photonics, nanoplasmonics offers interesting opportunities providing the material and dimensional compatibility with ultra-small silicon electronics and the integrative functionality using hybrid photonic and electronic nanostructures. For sensing applications, remarkable changes in scattering colors stemming from a plasmonic coupling effect of gold nanoplasmonic particles have been utilized to demonstrate a detection of microRNAs at the femtomolar level with selectivity. As top-down or bottom-up fabrication of such nanoscale structures is limited to more conventional substrates, we have approached the controlled fabrication of highly ordered nanostructures using a transfer printing of pre-functionalized nanodisks on flexible substrates for more enabling applications of nanoplasmonics.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2003년도 추계학술대회논문집
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• pp.107-110
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• 2003

The sheet metal shearing process is normally used in the precision elements such as semi-conductor components. In precision elements, burrs usually reduce the quality of machined parts and cause interference, jamming and misalignment during assembly procedures and because of their sharpness, they can be safety hazard to personnel. Furthermore, not only burrs are hard to predict and avoid, but also deburring, the process of removing burrs, is time-consuming and costly. In order to get the burr-free parts, therefore, we developed the precise burr measuring system using the laser. Using the X-Y precious table, we used vertical measuring method. Through the laser measurement system, we gain the minute analog signal, so this signal was amplified by the electric circuit. Finally, we gained the realtime burr data using A/D converter, PC. By introducing the novel laser measuring method which employing vertical measurement mechanism, we could get fast and precious burr data. Through the experiments, the accuracy of the developed system is proved. The burr height measured during the punching process can be used for automatic deburring and in-situ aligning.