http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
3차원 LIGA 미세구조물 제작을 위한 마이크로 액추에이터 내장형 X-선 마스크
이광철,이승섭,Lee, Kwang-Cheol,Lee, Seung-S. 대한기계학회 2002 大韓機械學會論文集A Vol.26 No.10
We present a novel method for 3D microfabrication with LIGA process that utilizes a deep X-ray mask in which a micro-actuator is integrated. The integrated micro-actuator oscillates the X-ray absorber, which is formed on the shuttle mass of the micro-actuator, during X-ray exposures to modify the absorbed dose profile in X-ray resist, typically PMMA. 3D PMMA microstructures according to the modulated dose contour are revealed after GG development. An X-ray mask with integrated comb drive actuator is fabricated using deep reactive ion etching, absorber electroplating, and bulk micromachining with silicon-on-insulator (SOI) wafer. 1mm $\times$ 1 mm, 20 $\mu$m thick silicon shuttle mass as a mask blank is supported by four 1 mm long suspension beams and is driven by the comb electrodes. A 10 $\mu$m thick, 50 $\mu$m line and spaced gold absorber pattern is electroplated on the shuttle mass before the release step. The fundamental frequency and amplitude are around 3.6 kHz and 20 $\mu$m, respectively, for a do bias of 100 V and an ac bias of 20 $V_{p-p}$ (peak-peak). Fabricated PMMA microstructure shows 15.4 $\mu$m deep, S-shaped cross section in the case of 1.6 kJ $cm^{-3}$ surface dose and GG development at 35$^{\circ}C$ for 40 minutes.
탄소 기반의 고주파 나노 역학 공진기의 제작 및 동역학적 특성에 대한 연구
이승훈(Seung Hoon Lee),민범기(Bumki Min),이광철(Kwang-Cheol Lee),박세일(Se Il Park),이승섭(Seung S. Lee) 대한기계학회 2009 대한기계학회 춘추학술대회 Vol.2009 No.11
Nanomechanical resonators have attracted much attention in the last decade due to superior performance with high sensitivity and high oscillation frequency. In this paper, we propose carbon-based high frequency nanomechanical resonators by utilizing pyrolyzed carbon layers with embedded single walled carbonnanotube (swCNT) layers. SwCNTs are used as a reinforcement material and also lower the density of the resonator. Dynamic behaviors of the fabricated resonators, including fundamental frequency, Q-factor, and frequency tuning characteristics were investigated using magnetomotive dynamic flexural measurements. We believe that the carbon-based nanomechanical resonators have promising applications in sensitive nanodevices with low power consumption. These materials are also ideal because of the low-cost batch processing capability and could be an alternative for silicon-based nanodevices.
온도 변화를 이용한 고분자 막 마이크로 액추에이터의 공진 주파수 튜닝
이승훈(Seung Hoon Lee),이석우(Seok Woo Lee),권혁준(Hyuk-Jun Kwon),이광철(Kwang-Cheol Lee),이승섭(Seung S. Lee) 대한기계학회 2008 대한기계학회 춘추학술대회 Vol.2008 No.11
Resonant frequency tuning of micro devices is essential to achieve performance uniformity and high sensitivity. Previously reported frequency tuning methods using electrostatic force or mass deposition are not directly applicable to non-conducting polymer devices and have limitations such as dielectric breakdown or low tunable bandwidth. In this paper, thermally frequency-tunable microactuators with poly-dimethylsiloxane membranes are proposed. Permanent and/or nonpermanent frequency tunings are possible using a simple temperature control of the device. Resonant frequency and Q-factor variations of devices according to temperature change were studied using a micro heater and laser Doppler vibrometer. The initial resonant frequencies determined by polymer curing and hardening temperatures are reversibly tuned by thermal cycles. The measured resonant frequency of 9.7 ㎑ was tuned up by ~ 25% and Q-factor was increased from 14.5 to 27 as the micro heater voltage increased from 0 to 70 V.
표면처리된 탄소 마이크로니들을 이용한 초소수성 표면 제조
이정아(Jung A Lee),이석우(Seok Woo Lee),이승섭(Seung S. Lee),박세일(Se Il Park),이광철(Kwang-Cheol Lee) 대한기계학회 2009 대한기계학회 춘추학술대회 Vol.2009 No.11
This paper reports a fabrication method of high aspect ratio (HAR) carbon microneedle arrays with controlled geometry and a creation of a superhydrophobic surface utilizing HMDS (hexamethyldisilazane)-modified carbon microneedles. Carbon microneedles are obtained through lithography and thermal treatment, which have aspect ratios greater than ten and nanoscale tips by volume shrinkage during pyrolysis of the fabricated SU-8 microneedles. We also stuied the wetting property of carbon microneedle arrays with different base diameters and spacing between needles and created an extremely water-repellent surface using HMDS-treated carbon microneedles. The proposed surface will be of great interest in self-cleaning, low-drag microfluidics, and lab-on-a-chip.
〈학술논문〉 비틀림 셀프 펌핑 스프링이 내재된 π-형상 파라메트릭 공진기 개발
김진하(Jin Ha Kim),이승훈(Seung Hoon Lee),이정아(Jung A Lee),심승보(Seung-Bo Shim),이광철(Kwang-Cheol Lee),이승섭(Seung S. Lee) 대한기계학회 2009 대한기계학회 춘추학술대회 Vol.2009 No.11
Mechanically pumped parametric resonators have advantages in size minimizing and sensitivity increasing of sensors, but only limited studies have been done, despite its potential capabilities. Here we report new π-shape parametric resonators - constructed with operating cantilevers and pumping beams - in which torsional self pumping springs are included. Zero-displacement points of pumping beams are identified using areal calculation method to contribute only torsional pumping. Suggested nanocantilevers are fabricated by simple patterning and etching process. Resonance frequencies of operating cantilevers and pumping beams are measured, and the measured resonance frequencies are compared with vibration modes simulation results. We perform DC tuning for resonance frequency matching. The suggested design of resonator establishes development very small and high sensitivity sensors.
이성근,이광철,이승섭,Lee, Sung-Keun,Lee, Kwang-Cheol,Lee, Seung-S. 대한기계학회 2002 大韓機械學會論文集A Vol.26 No.11
Microlenses and microlens arrays are fabricated using a novel fabrication technology based on the exposure of a resist (usually PMMA) to deep X-rays and subsequent thermal treatment. The fabrication technology is very simple and produces microlenses and microlens arrays with good surface roughness (less than 1 nm). The molecular weight and glass transition temperature of PMMA is reduced when it is irradiated with deep X-rays. The microlenses is produced through the effects of volume change, surface tension, and reflow during thermal treatment of irradiated PMMA. The geometry of the microlens is determined by parameters such as the X-ray dose applied to the PMMA, the diameter of the microlens, along with the heating temperature, heating time, and cooling rate in the thermal treatment. Microlenses are produced with diameters ranging from 30 to 1500 ${\mu}{\textrm}{m}$. The modified LIGA process is used not only to construct hemispherical microlenses but also structures that are rectangular-shaped, star-shaped, etc.
마이크로 채널 반응기 내 상압 글로우 플라즈마 생성 및 응용
이대훈(Dae Hoon Lee),박현향(Hyoun-Hyang Park),이재옥(Jae-Ok Lee),이승섭(Seung. S. Lee),송영훈(Young-Hoon Song) 대한기계학회 2008 대한기계학회 춘추학술대회 Vol.2008 No.11
In this work, to make it possible to generate glow discharge in atmospheric pressure condition with relatively high and wide electric field, micro channel reactor is proposed. Si DRIE and Cr deposition by Ebeam evaporation is used to make channel and bottom electrode layer. Upper electrode is made from ITO glass to visualize discharge within micro channel. Fabricated reactor is verified by generating uniform glow plasma with N2 / He gases each as working fluid. The range of gas electric field to generate glow plasma is from about 200 V/㎝ and upper limit is not observed in tested condition of up to 150 ㎸/㎝. This data shows that micro channel plasma reactor is more versatile. Indirect estimation of electron temperature in this reactor can be inferred that the electron temperature within glow discharge in micro reactor lies 0~2eV. This research demonstrates that the reactor is appropriate in application that needs to maintain low temperature condition during chemical process.
미세 채널에서 가스 경계면을 이용한 미세 유체의 폭 좁히기
손상욱(Sang Uk Son),이승섭(Seung S. Lee) 대한기계학회 2003 대한기계학회 춘추학술대회 Vol.2003 No.11
A novel method for narrowing microfluid width in microchannel, essential in flow cytometry, was presented by forming and inflating gas boundaries symmetrically in perpendicular direction. The gas boundaries were generated by heating water with microheaters located beneath the microchannel of which shape was determined from empirical manner. The width of microchannel, which was 300 ㎛, was narrowed and maintained as up to 22 ㎛ which was near regular cell size. In the process the gas boundaries moved back and forth for adjustment of micro fluid width and it was maintained by two factors of pressure in the gas boundaries and the flow velocity of microfluid. The stable state began to be distorted at the velocity over 17.8 ㎜/s. The method has advantages of preserving cells intact from electrical fields and acoustic waves as usual in other on-chip devices, and using no external apparatus as syringe pumps in conventional method. Principle and fabrication were described in text as well the experiments for illustration.