• 센서학회지
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• 제23권5호
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• pp.342-348
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• 2014

This paper introduced a novel multi-gas sensor detector with simple signal processing algorithm. This device was evaluated by investigating the characteristics of combustible materials using fire-generated smell and smoke. Plural sensors including TGS821, TGS2442, and TGS260X were equipped to detect carbon monoxide, hydrogen gas, and gaseous air contaminants which exist in cigarette smoke, respectively. Signal processing algorithm based on the difference of response times in fire-generated gases was implemented with early and accurately fire detection from multiple gas sensing signals. All fire experiments were performed in a virtual fire chamber. The cigarette, cotton fiber, hair, polyester fiber, nylon fiber, paper, and bread were used as a combustible material. This analyzing software and sensor controlling algorithm were embedded into 8-bit micro-controller. Also the detected multiple gas sensor signals were simultaneously transferred to the personnel computer. The results showed that the air pollution detecting sensor could be used as an efficient sensor for a fire detector which showed high sensitivity in volatile organic compounds. The proposed detecting algorithm may give more information to us compared to the conventional method for determining a threshold value. A fire detecting device with a multi-sensor is likely to be a practical and commercial technology, which can be used for domestic and office environment as well as has a comparatively low cost and high efficiency compared to the conventional device.

• 센서학회지
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• 제20권5호
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• pp.357-362
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• 2011

This paper demonstrates a novel electrodynamic technique to remove particles from the wall of microchannels. Dielectrohporesis(DEP) is generated by applying alternating electric potentials to the interdigitated electrodes integrated at the bottom of the micro-channel. The proposed technique is applied to a general microfluidic channel as a feasibility test. To examine the wall loss reduction efficiency, 10 ${\mu}m$ diameter Polystyrene latexes(PSL) were supplied to the inlet of the device. Then, the concentration of collected particles through devices was measured. In the experiment for 10 ${\mu}m$ diameter PSL particles, the concentration of the injected particles was $174.25{\times}10^4$ particles/ml. However, the concentration of collected particles at the outlet was $52.25{\times}10^4$ particles/ml. Only 30 % of particles had arrived at the outlet and 70 % of particles had adhered to the wall of the microfluidic channel. By applying alternating electric potentials from 0 to 20 $V_{pp}$ at 3 MHz, the concentration of injected particles was 135.00${\times}10^4$ particles/ml, the concentration of collected particles was increased as $105.25{\times}10^4$ particles/ml at 20 $V_{pp}$ at the outlet. When the electric potential was 20 $V_{pp}$, the particle loss was decreased by 39 % (initial loss: 70 %, loss at 20 Vpp: 31 %) with 10 ${\mu}m$ particle. The particle loss was decreased along to the incensement of electric potentials and the enlargement of the diameter of particles. According to these measured results, it was confirmed that the proposal of using DEP technique could be a good candidate for particle loss reduction in micro-particle processing chip application. Moreover, it is expected that the proposed technique could enhance performance of microfluidic and biochip devices.

• 한국측량학회지
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• 제36권2호
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• pp.75-84
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• 2018

본 연구의 목적은 MEMS 기반의 INS를 적용한 저가형 MMS를 개발하고, 개발된 MMS를 이용하여 x, y의 평면 거리오차가 0.546m인 정확도를 확보하여 도로시설물의 판독에 활용하고자 함에 있다. MMS 기술은 해외 유수의 측량장비제작 업체를 중심으로 지리정보 구축을 위한 새로운 측량기술로 활발하게 사용되고 있지만 국내에서는 아직 관련 연구가 초기단계에 있다. 또한, MMS 장비개발은 몇몇 연구원 및 업체에서 시도를 하였으나 안정화가 이루어지지 않은 시작품 단계에 불과하다. 이러한 MMS 기술은 빠른 시간 내에 지형 지물 데이터를 취득할 수 있어 정밀지도 제작과 도로시설물 데이터 취득에 활용되고 있다. 따라서 본 연구에서는 MMS 제작에 사용하는 각종 센서(LiDAR, CCD camera, GPS/INS, DMI 등)를 동기화하여 MEMS 기반의 INS를 탑재한 저가형 MMS를 개발하고자 한다.

• Current Optics and Photonics
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• 제1권2호
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• pp.143-149
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• 2017

LED arrays with pixel numbers of $3{\times}3$, $4{\times}4$, and $5{\times}5$ have been studied in this paper in order to enhance the optical output power and decrease heat dissipation of an AlGaInP-based light emitting diode display device (pixel size of $280{\times}280{\mu}m$) fabricated by micro-opto-electro-mechanical systems. Simulation results showed that the thermal resistances of the $3{\times}3$, $4{\times}4$, $5{\times}5$ arrays were $52^{\circ}C/W$, $69.7^{\circ}C/W$, and $84.3^{\circ}C/W$. The junction temperature was calculated by the peak wavelength shift method, which showed that the maximum value appears at the center pixel due to thermal crosstalk from neighboring pixels. The central temperature would be minimized with $40{\mu}m$ pixel pitch and $150{\mu}m$ substrate thickness as calculated by thermal modeling using finite element analysis. The modeling can be used to optimize parameters of highly integrated AlGaInP-based LED arrays fabricated by micro-opto-electro-mechanical systems technology.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2018년도 추계학술대회
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• pp.328-330
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• 2018

태양 에너지를 전기 에너지로 변환시키는 장치가 설치된 해상 부유체는 파도에 의해서 운동한다. 해상 부유체의 안전성을 평가하기 위해서는 부유체 운동의 측정과 해석이 필요한데, 일반적으로 6자유도 운동을 이용한다. 6자유도 운동은 저전력, 소형, 저가의 특징을 갖고 있는 MEMS(Micro-Electro Mechanical System)를 이용하여 측정할 수 있다. 문제는 MEMS의 낮은 정밀도이다. 본 연구에서는 이러한 MEMS를 이용한 해상 태양광 부유체의 거동을 측정하고, 측정한 거동을 이용한 안전성 평가 기법에 관하여 검토하였다. 연구결과 3축의 가속도계와 3축의 자이로스코프를 이용한 관성 측정 플랫폼을 통해서 해상 부유체의 모델링과 안전성 평가가 가능함을 알았다.

• 청정기술
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• 제9권3호
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• pp.101-105
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• 2003

MEMS(Micro Electro Mechanical System) 기술에서 실리콘 식각기술의 중요성으로 플라즈마 식각기술의 개발이 꾸준히 진행되고 있다. 본 연구에서는 ICP(Inductive Coupled Plasma)를 이용하여 플라즈마를 발생시켜, 이온에너지를 증가시키지 않고도 이온밀도를 높이고 이온입자들에 의한 식각의 방향성을 가할 수 있는 새로운 플라즈마 기술을 이용하였다. 이같이 플라즈마를 이용하여 실리콘웨이퍼를 식각하여 제조하는 MEMS 응용분야는 다양하나, 본 연구에서는 미생물배양에 응용할 수 있는 PCR(Polymerase Chain Reaction)장치 제작을 위한 식각에 이용하였다. Platen power, Coil power 및 Process pressure에 다양한 변화를 주어 각 변수에 따른 식각속도를 관찰하였다. 각 공정별 변수를 변화시킨 결과 Platen 12W, Coil power 500W, 식각/Passivation Cycle 6/7sec 일 경우 식각속도는 $1.2{\mu}m/min$ 이었고, sidewall profile은 $90{\pm}0.7^{\circ}$로 나타나 매우 우수한 결과를 보였다. 분 연구에 SF6를 식각에 이용하였으며 공정의 최적화를 통하여 사용량을 최소화하여환경영향이 최소가 될 수 있는 가능성이 있었다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회B
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• pp.2366-2371
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• 2007

Spray combustion characteristics of a conducting fuel electrospray have been studied for clean combustion technology. The multiplexing system which can retain the characteristics of the cone-jet mode is inevitable for the electrospray application. Charged micro droplets can be obtained in almost uniform size during operating the electrospray in the cone-jet mode. This experiment device set up the multiplexed grooved nozzle system with the extractor. Using the grooved nozzle, the stable cone-jet mode can be achieved at the each groove in the grooved mode. This electrospray system was applied to the diffusion combustion. It is the first step to discover the diffusion combustion characteristics of the electrospray. In case of the single grooved nozzle electrospray, the diffusion flames are occurred at each jet of grooved mode and they are quite stable. The exhaust gas analysis was indicated that there is the critical point which can make very stable diffusion combustion.

• International Journal of Aeronautical and Space Sciences
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• 제11권3호
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• pp.234-239
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• 2010

The utilization of micro-electro-mechanical system (MEMS) gyros and accelerometers in low-level inertial measurement unit (IMU) influences cost effectiveness in a positive way under the condition that device error characteristics are fully calibrated. The conventional calibration process utilizes a rate table; however, this paper proposes a new method for achieving reference calibration data from the natural motion of pendulum to which the IMU undergoing calibration is attached. This concept was validated with experimental data. The pendulum angle measurements correlate extremely well with the solutions acquired from the pendulum equation of motion. The calibration data were computed using the regression method. The whole process was validated by comparing the measurement from the 6 sensor components with the measurements reconstructed using the identified calibration data.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2007년도 7th International Meeting on Information Display 제7권2호
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• pp.1125-1128
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• 2007

The laminating technique for developing flexible liquid crystal display was demonstrated by using a thin UV curable polymer film and a plastic substrate with patterned polymer wall structure. We adopted the rigid wall structure to provide a solid mechanical support for the stable molecular alignment of liquid crystals (LCs) in the device. The cover film was prepared to have an ability of aligning LC molecules by patterning a micro-groove structure using the soft-lithographic process. These two substrates can be assembled tightly by the laminating and one-step UV irradiation process because of the adhesive nature of the used UV curable polymers. Proposed method can be used to fabricate the flexible LC display with simplicity and also be applicable for a cost-effective roll-to-roll process.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2004년도 추계학술발표대회 논문집
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• pp.19-22
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• 2004

A numerical system to extract effective elastic properties of polycrystalline thin-films for MEMS devices is already developed. In this system, the statistical model based on lattice system is used for modeling the microstructure evolution simulation and the key kinetics parameters of given micrograph, grain distributions and deposition process can be extracted by inverse method proposed in the system. In this work, the effective elastic properties of polysilicon, $BaTiO_3\;and\;ZrTiO_4$ are extracted using this system and by employing the fraction of the potential site($f_P$) as a kinetics parameter for the microstructure evolution, the statistical tendency of these materials is studied.