• 조명전기설비학회논문지
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• 제21권7호
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• pp.54-60
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• 2007

15개의 광섬유 격자를 이용하여 전력설비의 온도변화를 상시 감시하는 분배형 광섬유 온도센서 시스템을 제작하였다. MEMS 파장가변 필터를 사용하는 복조시스템의 비선형 동작특성에 의한 측정오차를 보상하기 위하여 Fabry-Perot ITU 필터의 투과파장을 기준으로 하는 다항식 피팅 알고리즘을 사용하였다. 실험을 통하여 보상알고리즘이 구동주파수와 무관하게 센서시스템의 정밀도를 유지하는 것을 확인하였으며 기준 온도계로 사용한 써모커플과의 선형화 오차는 약 0.18[%]로 측정되었다.

• 한국음향학회지
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• 제31권4호
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• pp.205-213
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• 2012

동해와 남해에서 능동 음향센서 배열 신호를 측정하고, 신호의 공간 상관성을 분석하였다. 주변소음, 표적신호, 해수면과 후방산란 신호, 해상풍, 수직 수온을 25시간 동안 동시에 관측하였다. 남해 측정에서는 분석결과로 부터 주변소음의 공간 상관성이 표적신호 보다 매우 낮고, 표적신호는 전체 음향센서에서 0.5 이상의 상관성을 보였다. 동해 측정에서는 해수면 잔향 신호의 공간 상관성은 해수면 입사각이 클때 높고, 상관성이 0.5이상인 무차원화된 배열의 최대길이는 26도의 입사각에서 3.0, 32도의 입사각에서 3.5였다. 배열센서의 형상과 배열성능을 결정하는 기준이 되는 공간 상관성 파악을 위해서는 향후에 다양한 시공간 변동을 포함한 지속적인 관측이 필요하다.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2004년도 Asia Display / IMID 04
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• pp.75-80
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• 2004

By the SOG (System-on-Glass) technology with excimer laser anneal process, the number of IC chips and the area of the mounted IC chips on the printed circuit board are reduced. In new circuit integrations on the glass substrate, we have developed D/A converter including the new capacitor array, amplifier comprising the original comparators and new display device with capturing images by integrated sensor into a pixel. This paper discusses the application of circuit integration of low-temperature poly-Si.

• 한국정보통신학회논문지
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• 제19권9호
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• pp.2087-2092
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• 2015

산업이 발전함에 따라 제조업 및 서비스 제품 등 다양한 분야에 열전달 장치 및 열전달 시스템이 활용되고 있다. 열전달 시스템의 자동화 및 모니터링 시스템을 통하여 환경을 관리하기 위해서는 온도 측정이 필요한 대상물의 직접적인 온도 및 측정 대상물의 주위 온도에 대한 계측이 필수요소라 할 수 있다. 특히, 이러한 온도 측정에 관한 두 가지 요소에 대하여 본 논문에서는 비접촉온도센서를 활용하여 온도 계측이 필요한 대상물에 센스를 직접 접촉하지 않고 대상물의 표면 온도를 계측할 수 있는 시스템과 대상물 주위 온도를 계측할 수 있는 모듈을 소형 MCU(microcontroller unit) 기반으로 설계하여 계측된 온도 데이터를 USN(Ubiquitous Sensor Network)기반의 지그비(ZigBee) 통신을 활용하여 온도 모니터링 시스템을 제시하고자 한다. 본 논문에서는 대상물의 온도와 주위 온도에 관한 정보를 계측하기 위하여 비접촉온도센서를 활용하여 대상물의 표면 온도 및 주위 온도를 계측할 수 있는 펌웨어 기반의 시스템을 설계하였다. 또한, 계측된 온도 정보 데이터를 지그비 통신을 기반으로 원격으로 온도 데이터를 모니터링 할 수 있는 시스템을 제시하고자 한다.

• 센서학회지
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• 제31권6호
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• pp.366-370
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• 2022

A 12 ㎛ pixel-sized 360 × 240 microbolometer focal plane array (MBFPA) was fabricated using a complementary metaloxide-semiconductor (CMOS)-compatible process. To release the MBFPA membrane, an amorphous carbon layer (ACL) processed at a low temperature (<400 ℃) was deposited as a sacrificial layer. The thermal time constant of the MBFPA was improved by using serpentine legs and controlling the thickness of the SiNx layers at 110, 130, and 150 nm on the membrane, with response times of 6.13, 6.28, and 7.48 msec, respectively. Boron-doped amorphous Si (a-Si), which exhibits a high-temperature coefficient of resistance (TCR) and CMOS compatibility, was deposited on top of the membrane as an IR absorption layer to provide heat energy transformation. The structural stability of the thin SiNx membrane and serpentine legs was observed using field-emission scanning electron microscopy (FE-SEM). The fabrication yield was evaluated by measuring the resistance of a representative pixel in the array, which was in the range of 0.8-1.2 Mohm (as designed). The yields for SiNx thicknesses of SiNx at 110, 130, and 150 nm were 75, 86, and 86%, respectively.

• 한국재료학회지
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• 제18권2호
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• pp.69-72
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• 2008

A sensor element array for combinatorial solution deposition research was fabricated using LTCC (Low-temperature Co-fired Ceramics). The designed LTCC was co-fired at $800^{\circ}C$ for 1 hour after lamination at $70^{\circ}C$ under 3000 psi for 30 minutes. $SnO_2$ sol was prepared by a hydrothermal method at $200^{\circ}C$ for 3 hours. Tin chloride and ammonium carbonate were used as raw materials and the ammonia solution was added to a Teflon jar. 20 droplets of $SnO_2$ sol were deposited onto a LTCC sensor element and this was heat treated at $600^{\circ}C$ for 5 hours. The gas sensitivity ($S\;=\;R_a/R_g$) values of the $SnO_2$ sensor and 0.04 wt% Pd-added $SnO_2$ sensor were measured. The 0.04 wt% Pd-added $SnO_2$ sensor showed higher sensitivity (S = 8.1) compared to the $SnO_2$ sensor (S = 5.95) to 200 ppm $CH_3COCH_3$ at $400^{\circ}C$.

• 한국농업기계학회:학술대회논문집
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• 한국농업기계학회 2017년도 춘계공동학술대회
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• pp.122-122
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• 2017

Recently, environmental problems have become an area of growing interests. In-situ monitoring of water quality is fundamental to most environmental applications. The accurate measurement of nitrate concentrations is fundamental to understanding biogeochemistry in aquatic ecosystems. Several studies have reported that one of the most feasible methods to measure nitrate concentration is the use of Ion Selective-electrodes (ISEs). The ISE application to water monitoring has several advantages, such as direct measurement methodology, high sensitivity, wide measurement range, low cost, and portability. However, the ISE methods may yield inconsistent results where there was a difference in temperature between the calibration and measurement solutions, which is associated with the temperature dependence of ionic activity coefficients in solution. In this study, to investigate the potential of using the combination of a temperature sensor and nitrate ISEs for minimizing the effect of temperature on real-time nitrate sensing in natural water, a prototype of on-site water monitoring system was built, mainly consisting of a sensor chamber, an array of 3 ISEs, an waterproof temperature sensor, an automatic sampling system, and an arduino MCU board. The analog signals of ISEs were obtained using the second-order Sallen-key filter for performing voltage following, differential amplification, and low pass filtering. The performance test of the developed water nitrate sensing system was conducted in a monitoring station of drinking water located in Jeongseon, Kangwon. A temperature compensation method based on two-point normalization was proposed, which incorporated the determination of temperature coefficient values using regression equations relating solution temperature and electrode signal determined in our previous studies.

• 한국태양에너지학회 논문집
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• 제32권4호
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• pp.1-8
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• 2012

A Fiber Bragg Grating (FBG) sensor imbedded small wind turbine blade was manufactured to experimentally investigate the feasibility to embed FBG sensors between layers of glass fiber to monitor dynamic strains of the wind turbine blade. The blade which is similar to a commercial 300 W wind turbine blade was manufactured with glass fiber as a reinforcement and epoxy resin as base material. A total of five FBG sensors including one temperature sensor were imbedded in the blade to sense mechanical strain and temperature. While manufacturing the blade, residual strain and temperature that occurred in the small wind turbine blade were monitored using the imbedded FBG sensor array. To examine the sensor performance, an impact test was carried out. The experimental results from the FBG sensors were close to those from electrical strain gages mounted on the blade root surface. The mode shapes of the blade were analyzed also using a commercial Ansys simulation with a model obtained from a three dimensional laser scanning of the blade.

• 한국재료학회지
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• 제23권12호
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• pp.667-671
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• 2013

We present an easy method of preparing two-dimensional (2D) periodic hollow tin oxide ($SnO_2$) hemisphere array gas sensors using polystyrene (PS) spheres as a template. The structures were fabricated by the sputter deposition of thin tin (Sn) metal over an array of PS spheres on a planar substrate followed by calcination at an elevated temperature to oxidize Sn to $SnO_2$ while removing the PS template cores. The $SnO_2$ hemisphere array structures were examined by scanning electron microscopy and X-ray diffraction. The structures were calcined at various temperatures and their sensing properties were examined with varying operation temperatures and concentrations of nitric oxide (NO) gas. Their gas-sensing properties were investigated by measuring the electrical resistances in air and the target gases. The measurements were conducted at different NO concentrations and substrate temperatures. A minimum detection limit of 30 ppb, showing a sensitivity of S = 1.6, was observed for NO gas at an operation temperature of $150^{\circ}C$ for a sample having an Sn metal layer thickness corresponding to 30 sec sputtering time and calcined at $600^{\circ}C$ for 2 hr in air. We proved that high porosity in a hollow $SnO_2$ hemisphere structure allows easy diffusion of the target gas molecules. The results confirm that a 2D hollow $SnO_2$ hemisphere array structure of micronmeter sizes can be a good structural morphology for high sensitivity gas sensors.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2001년도 Proceedings ICPE 01 2001 International Conference on Power Electronics
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• pp.626-630
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• 2001

MPPT (maximum power point tracking) control is very important for the practical PV (photovoltaic) systems to maintain efficient power generating conditions irrespective of the deviation in the PV array insolation or/and temperature conditions. Although a plenty of researches have been done so far, most of them are too costly because of being too dependant on expensive sensors for measuring photovoltaic power and micro-processors for achieving elaborate and complicated control strategies. From this point of view, authors have been researching on sensor-less approaches for MPPT control, and have proposed two types of new control schemes 'Power Equilibrium Scheme' and 'Limit Cycle Scheme'. This paper summarises these two schemes with focussing on their :- operating principles and some results of simulation and experiments.