• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 2002년도 Proceedings of the International Welding/Joining Conference-Korea
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• pp.781-784
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• 2002

Adhesion phenomenon is more significant for smaller objects, because adhesional force is proportional to size of the objects while gravitational force is proportional to the third power of it. For the purpose of microassembly, theoretical understanding is required for the Adhesion phenomenon. Authors have developed a force measurement system in an ultra-high vacuum chamber of Auger electron spectroscopy. The force between arbitrary combination of materials can be measured at a pressure less than 100 nPa after and before Ar ion sputtering and chemical analysis for several atomic layers of the surface. The results are successfully interpreted with a theory of contact mechanics. Since surface energy is quite important in the interpretation, electronic theory is used to evaluate the surface energy. In the manipulation of small objects, the adhesional force is always attractive. Repulsive force is essential for the manipulation. It can be generated by Coulomb interaction. The voltage required for detachment is theoretically analyzed and the effect of boundary conditions on the detachment is obtained. The possibility and limitations of micro-manipulation using both the adhesion phenomenon and Coulomb interaction are theoretically clarified. Its applicability to nano-technology is found to be expected.

• 열처리공학회지
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• 제36권3호
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• pp.137-144
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• 2023

Micro electro mechanical systems (MEMS) and precision machines require excellent friction and wear characteristics to improve energy efficiency generated during sliding motion. In this study, DLC thin film with high hardness and low friction was deposited on STS304 substrate material by CVD method, and dot-shaped convex and concave micropatterns were fabricated by photolithography process. The diameter of the pattern was 20 ㎛, the pitch was 40 ㎛, and a pattern having a mesh type arrangement was fabricated and an abrasion test was performed. The results of the wear test on the micro pattern confirmed that the friction coefficient characteristics were improved compared to STS 304 and DLC thin films. In addition, in this result, the micro-pattern showed 11.4% more improved friction coefficient than the DLC thin film. The friction coefficient characteristics for convex and concave patterns of the same size showed almost similar results.

• 전자공학회논문지
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• 제54권3호
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• pp.31-36
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• 2017

본 논문에서는 가상의 적외선 영상을 투사하여 적외선 검출기의 성능 평가를 위한 목적으로 사용되는 적외선 영상 투사장치 (Infrared scene projector, IRSP)의 내부에서 적외선을 방사하는 역할을 하는 적외선 에미터 소자에 대한 연구가 수행되었다. 적외선 에미터 소자의 구조를 설계한 후 설계된 소자의 특성 파라미터들을 추출하였으며 각 특성 파라미터에 근거한 소자의 성능을 유한 요소법을 통해 예측하였다. 또한 소자를 구성하는 각 부분의 특성에 따른 물질 선정 후 MEMS 기반 반도체 공정기술을 적용하여 에미터 단위소자를 제작하였고 중적외선 대역($3{\sim}5{\mu}m$)의 적외선을 관찰할 수 있는 적외선 영상 현미경을 사용하여 진공 환경을 갖춘 챔버 내부에서 소자의 성능을 측정한 결과 최대 423K의 유효온도 및 22msec의 응답 시간을 나타내는 것을 확인하였다.

• Smart Structures and Systems
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• 제6권3호
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• pp.225-238
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• 2010

We report on the development of a new technology for the fabrication of Micro-Electro-Mechanical-System (MEMS) strain sensors to realize a novel type of crackmeter for health monitoring of ageing civil infrastructures. The fabrication of micromachined silicon MEMS sensors based on a Silicon On Insulator (SOI) technology, designed according to a Double Ended Tuning Fork (DETF) geometry is presented, using a novel process which includes a gap narrowing procedure suitable to fabricate sensors with low motional resistance. In order to employ these sensors for crack monitoring, techniques suited for bonding the MEMS sensors on a steel surface ensuring good strain transfer from steel to silicon and a packaging technique for the bonded sensors are proposed, conceived for realizing a low-power crackmeter for ageing infrastructure monitoring. Moreover, the design of a possible crackmeter geometry suited for detection of crack contraction and expansion with a resolution of $10{\mu}m$ and very low power consumption requirements (potentially suitable for wireless operation) is presented. In these sensors, the small crackmeter range for the first field use is related to long-term observation on existing cracks in underground tunnel test sections.

• 한국우주과학회:학술대회논문집(한국우주과학회보)
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• 한국우주과학회 2009년도 한국우주과학회보 제18권2호
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• pp.47.4-47.4
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• 2009

초소형전기기계시스템(MEMS: Micro-Electro-Mechanical Systems) 기술로 제작된 마이크로미러 어레이를 장착한 MEMS 우주망원경은 특유의 광시야각 감시, 목표 확인, 확대 및 고속 추적 기능을 가지며 고층대기에서의 초대형 방전현상과 같이 넓은 영역에서 드물게 임의로 일어나는 섬광현상을 관측하기에 최적이다. 러시아 과학위성 Tatiana-2의 주 탑재체로 선정된 극소형 MEMS 우주망원경 MTEL(MEMS Telescope for Extreme Lightning)은 광시야각 감시와 목표 확인을 위한 트리거망원경, 목표 확대와 고속추적을 위한 확대망원경 및 섬광현상의 분광측정을 위한 분광계로 구성되어 있다. 1년간의 개발 및 성능 검증 후 MTEL은 위성탑재를 위한 모든 우주인증 시험을 성공적으로 마쳤다. 현재 MTEL은 Tatiana-2 위성에 탑재되어 있으며, 9월 18일에 우주로 발사되어 1-3년간 800km 궤도를 비행하며 지구 대기에서 발생하는 섬광현상을 관측할 예정이다. 이 발표에서는 MTEL 탑재체의 설계, 제작, 성능 측정 및 calibration 결과를 보고하고, 위성탑재를 위한 진동 및 충격, 열, 진공 및 전자기파 적합성 등의 우주인증 시험 결과 또한 보고한다. 또한 발사 후 과학위성 및 MTEL의 이 발표 때까지의 우주에서의 상황을 보고한다.

• Journal of Positioning, Navigation, and Timing
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• 제4권3호
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• pp.141-150
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• 2015

In this study, a Global Navigation Satellite System (GNSS) / Inertial Navigation System (INS) / odometer / barometer integrated navigation system that uses a commercial navigation device including Micro Electro Mechanical Systems (MEMS) accelerometer and gyroscope in addition to GNSS, odometer information obtained from a vehicle, and a separate MEMS barometer sensor was implemented, and the performance was verified. In the case of GNSS and GNSS/INS integrated navigation system that are generally used in a navigation device, the performance would deteriorate in areas where GNSS signals are not available. Therefore, an integrated navigation system that calculates a better navigation solution in areas where GNSS signals are not available compared to general GNSS/INS by correcting the velocity error of GNSS/INS using an odometer and by correcting the cumulative altitude error of GNSS/INS using a barometer was suggested. To verify the performance of the navigation system, a commercial navigation device (Softman, Hyundai Mnsoft, http://www.hyundai-mnsoft.com) and a barometer sensor (ST Company) were installed at a vehicle, and an actual driving test was performed. To examine the performance of the algorithm, the navigation solutions of general GNSS/INS and the GNSS/INS/odometer/barometer integrated navigation system were compared in an area where GNSS signals are not available. As a result, a navigation solution that has a smaller position error than that of GNSS/INS could be obtained in the area where GNSS signals are not available.

• 한국세라믹학회지
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• 제39권6호
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• pp.570-575
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• 2002

현재 전기 . 전자 기술의 추세는 소형화를 비롯하여 집적화, 저전력화, 저가격화의 장점을 가진 MEMS(Micro Electro Mechanical Systems) device의 개발에 주력하고 있으며, 이를 위해서는 고종횡비와 높은 식각 속도를 가진 HDP(High Density Plasma) etching 기술 개발이 필수적이라 할 수 있다. 이를 위하여 우리는 Inductively Coupled Plasma(ICP) 장비를 이용하여 각 공정 변수에 의한 실리콘 deep trench식각 반응을 연구하였다. 실험 공정 변수인 platen power, etch/passivation cycle time에서 etching 단계 시간에 따른 변화와 SF$_{6}$:C$_4$F$_{8}$ 가스유량을 변화시켜 연구하였으며 또한 이들의 profile, scallops, 식각 속도, 균일도, 선택비도 관찰하였다.

• 센서학회지
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• 제21권3호
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• pp.217-222
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• 2012

Optical coherence tomography(OCT) is a noninvasive optical imaging tool for biomedical applications. OCT can provide depth resolved two/three dimensional morphological images on biological samples. In this paper, we integrated an OCT system that was composed of an SLED(Superluminescent Light Emitting Diode, ${\lambda}_0$=1305 nm bandwith= 141 nm), a reference arm adopting a rapid scanning optical delay line(RSOD) to get high speed imaging, and a sample arm that used a micro electro mechanical systems(MEMS) scanning mirror. The sample arm contained a compact probe for imaging dental structures. The performance of the system was evaluated by imaging in-vivo human teeth with dental calculus, and the results indicated distinct appearance of dental calculus from enamel, gum or decayed teeth. The developed probe and system could successfully confirm the presence of dental calculus with a very high spatial resolution($6{\mu}m$).

• 한국전기전자재료학회논문지
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• 제19권8호
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• pp.732-736
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• 2006

This paper describes the physical characterizations of polycrystalline 3C-SiC thin films heteroepitaxially grown on Si wafers with thermal oxide, In this work, the 3C-SiC film was deposited by LPCVD (low pressure chemical vapor deposition) method using single precursor 1, 3-disilabutane $(DSB:\;H_3Si-CH_2-SiH_2-CH_3)\;at\;850^{\circ}C$. The crystallinity of the 3C-SiC thin film was analyzed by XPS (X-ray photoelectron spectroscopy), XRD (X-ray diffraction) and FT-IR (fourier transform-infrared spectometers), respectively. The surface morphology was also observed by AFM (atomic force microscopy) and voids or dislocations between SiC and $SiO_2$ were measured by SEM (scanning electron microscope). Finally, residual strain was investigated by Raman scattering and a peak of the energy level was less than other type SiC films, From these results, the grown poly 3C-SiC thin film is very good crystalline quality, surface like mirror, and low defect and strain. Therefore, the polycrystalline 3C-SiC is suitable for harsh environment MEMS (Micro-Electro-Mechanical-Systems) applications.

• Smart Structures and Systems
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• 제11권5호
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• pp.453-476
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• 2013

DuraMote is a remote sensing system developed for the "NIST TIP project: next generation SCADA for prevention and mitigation of water system infrastructure disaster". It is designed for supervisory control and data acquisition (SCADA) of ruptures in water pipes. Micro-electro mechanical (MEMS) accelerometers, which record the vibration of the pipe wall, are used detect the ruptures. However, the performance of Duramote cannot be verified directly on a water distribution system because it lacks an acceptable recordable level of ambient vibration. Instead, a long-span cable-stayed bridge is an ideal test-bed to validate the accuracy, the reliability, and the robustness of DuraMote because the bridge has an acceptable level of ambient vibration. The acceleration data recorded on the bridge were used to identify the modal properties of the structure and to verify the performance of DuraMote. During the test period, the bridge was subjected to heavy rain, wind, and a typhoon but the system demonstrates its robustness and durability.