• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회B
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• pp.2696-2699
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• 2008

Microfluidic chips have been frequently utilized to perform biochemical analysis, like cell culture, because they reduce the consumptions of analytes and reagents and automate multi-step analysis processes. It is often critical to monitor temperature in a microchannel for the analyses in order to control a reaction condition of bio or chemical molecules. We propose a novel method to monitor temperature of a microchannel flow by using polydiacetylene (PDA), a conjugated polymer, that has a unique property to transform its color from visible blue to fluorescent red by thermal stress. We inject PDA sensor droplets generated by hydrodynamic instability into a microchannel with a microheater incorporated on the channel bottom. Also, we change the channel temperature by providing the different electric power to the microheater. The results show that the florescence intensity of PDA sensor droplets linearly increases in response to the flow temperature increase within a certain range.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2009년도 춘계학술대회
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• pp.241-244
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• 2009

손목에서 맥박을 측정하기 위한 센서부의 최적화에 관하여 연구하였다. 센서부의 최적 구조를 알기위해서 센서패드 구조물의 형태, 크기 및 실리콘의 두께를 변화시켜 맥박 신호를 측정하였다. 본 실험에서 사용된 구조물의 형태는 각기 Empty, Rectangle, Embossing, Length, Width이다. 각 구조물의 형태마다 실리콘의 두께를 0~7 mm 까지 1 mm씩 늘려 가면서 출력 신호의 크기를 비교하였다.

• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2009년도 추계학술발표대회
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• pp.39-40
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• 2009

본 논문에서는 유헬스 시스템에 가장 기본이 되는 생체정보 측정에 대하여 하나의 휴대용 인터페이스만을 가지고 다양한 생체정보 측정기와 연계하여 다양한 생체정보를 취득할 수 있도록 하는 이식성 있는 임베디드 미들웨어 PSI(Portable Sensor Interface)를 제안한다. PSI는 U-health 서비스를 제공하기 위해 측정기 자동인식, 데이터 취득, 위험요소 표시 및 데이터 수집장치(DAS)와의 통신을 담당하는 기능을 갖는다.

• 한국통신학회논문지
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• 제36권12B호
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• pp.1708-1721
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• 2011

최근 구제역과 같은 가축질병으로 인한 살 처분된 가축매몰지의 적절한 모니터링 시스템의 필요성이 대두되고 있다. 그러나 현재 사용되는 모니터링 시스템은 살 처분된 매몰지 현장에서의 시료를 채취한 후 1~2주간의 모니터링 기간을 필요로 함으로 실시간 감시가 필요로 하는 매몰지에 대한 연속측정이 불가능하다. 이에 본 논문에서는 이런 실시간 모니터링을 가능하게 하는 우선 센서네트워크 기반의 가축매몰지 환경정보 모니터링 시스템 설계 및 구현을 제안한다. 제안된 시스템의 무선 센서노드는 환경센서(Dust, Co2, NH3, H2s, Temperature, Humidity)와 위치확인을 위한 GPS센서로 구성된다. 제안된 시스템은 게이트웨이를 통해 원격지 서버에 전송된 매몰지 환경정보를 분석함으로 언제 어디에서나 유해환경 모니터링이 기능하고 위치확인을 통한 상황에 따른 능동적인 대응을 가능케한다. 따라서 제안된 시스템의 유효성 검증을 위해 규정된 가스 배출관에 센서를 설치하였고, 통합 모니터링이 가능한 테스트 베드에서 실시간으로 수신된 데이터를 수집, 분석하여 시간의 변화에 따른 매몰지 위치의 악취환경변화를 모니터링 하였다. 이를 통한 상황에 따른 실시간 대응을 함으로 유사시 환경오염의 사전예방이 가능 한 것을 확인할 수 있었다.

• 한국해양생명과학회지
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• 제1권1호
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• pp.25-30
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• 2016

본 연구는 소형화된 홀 소자를 이용하여 국내 패류 양식 생물 중 가장 많은 생산량을 보이는 참굴(Crassostrea gigas)의 패각운동을 기초로, 연안역에서 빈산소에 대한 생물모니터링 시스템의 적용 가능성을 조사하였다. 정상상태 패각운동의 측정을 위해서 여과해수에서 측정한 결과, 참굴 개체는 평균 5~12 mm 정도의 개각상태를 유지하였으며, 패각운동 시 비교적 빠른 폐각상태를 보였다가 느린 속도의 개각상태의 운동이 관찰되었다. 하지만, 주·야간 사이에는 큰 차이가 없었다(p<0.05). 용존산소 농도를 7 mg l^-1에서 3 mg l^-1까지 감소시키면, 패각운동의 횟수는 증가를 나타내었으며, 파형도 정상상태와 다르게 불안정한 파형을 보였다. 또한 용존산소가 2 mg l^-1로 감소된 후에는 패각운동의 크기가 점차 작아지거나, 폐각상태를 지시하는 파형이 관찰되었다. 이와 같은 생물모니터링 시스템을 패류 양식에 활용하여 빈산소와 같은 해양환경의 이상변동을 신속히 감지할 수 있다면, 어업피해를 감소시킬 수 있을 것으로 기대된다.

• Progress in Superconductivity
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• 제9권1호
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• pp.23-28
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• 2007

In order to have a superconductive connection between the wire-wound pickup coil and input coil, typically Nb terminal blocks with screw holes are used. Since this connection structure occupies large volume, large stray pickup area can be generated which can pickup external noise fields. Thus, SQUID and connection block are shielded inside a superconducting tube, and this SQUID module is located at some distance from the distal coil of the gradiometer to minimize the distortion or imbalance of uniform background field due to the superconducting module. To operate this conventional SQUID module, we need a higher liquid He level, resulting in shorter refill interval. To make the fabrication of gradiometers simpler and refill interval longer, we developed a novel method of connecting the pickup coil into the input coil. Gradiometer coil wound of 0.125-mm diameter NbTi wires were glued close to the input coil pads of SQUID. The superconductive connection was made using an ultrasonic bonding of annealed 0.025-mm diameter Nb wires, bonded directly on the surface of NbTi wires where insulation layer was stripped out. The reliability of the superconductive bonding was good enough to sustain several thermal cycling. The stray pickup area due to this connection structure is about $0.1\;mm^2$, much smaller than the typical stray pickup area using the conventional screw block method. By using this compact connection structure, the position of the SQUID sensor is only about 20-30 mm from the distal coil of the gradiometer. Based on this compact module, we fabricated a magnetocardiography system having 61 first-order axial gradiometers, and measured MCG signals. The gradiometers have a coil diameter of 20 mm, and the baseline is 70 mm. The 61 axial gradiometer bobbins were distributed in a hexagonal lattice structure with a sensor interval of 26 mm, measuring $dB_z/dz$ component of magnetocardiography signals.

• 농촌계획
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• 제21권3호
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• pp.171-179
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• 2015

The objectives of this research have been focussed on 1) developing prediction techniques for the flash flood and landslide based on rainfall prediction data in agricultural area and 2) developing an integrated forecasting system for the abrupt disasters using USN based real-time disaster sensing techniques. This study contains following steps to achieve the objective; 1) selecting rainfall prediction data, 2) constructing prediction techniques for flash flood and landslide, 3) developing USN and communication network protocol for detecting the abrupt disaster suitable for rural area, & 4) developing mobile application and SMS based early warning service system for local resident and tourist. Local prediction model (LDAPS, UM1.5km) supported by Korean meteorological administration was used for the rainfall prediction by considering spatial and temporal resolution. NRCS TR-20 and infinite slope stability analysis model were used to predict flash flood and landslide. There are limitations in terms of communication distance and cost using Zigbee and CDMA which have been used for existing disaster sensors. Rural suitable sensor-network module for water level and tilting gauge and gateway based on proprietary RF network were developed by consideration of low-cost, low-power, and long-distance for communication suitable for rural condition. SMS & mobile application forecasting & alarming system for local resident and tourist was set up for minimizing damage on the critical regions for abrupt disaster. The developed H/W & S/W for integrated abrupt disaster forecasting & alarming system was verified by field application.

• 한국세라믹학회지
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• 제47권2호
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• pp.189-194
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• 2010

Compared with organic fluorophores, semiconductor quantum dots (QDs) have the better properties such as photostability, narrow emission spectra coupled to tunable photoluminescent emissions and exceptional resistance to both photo bleaching and chemical degradation. In this work, CdSe/ZnS QDs nanobeads were prepared by the incorporation of CdSe/ZnS QDs with mesoporous silica to use as the optical probe for detecting toxic and bio- materials with high sensitivity, CdSe/ZnS core/shell QDs were synthesized from the precursors such as CdO and zinc stearate with the lower toxicity than pyrotic precursors. The QD-nanobeads were characterized by transmission electron microscopy, FL microscopy, UV-Vis and PL spectroscopy, respectively.

• Molecules and Cells
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• 제43권6호
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• pp.530-538
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• 2020

The Gustatory system enables animals to detect toxic bitter chemicals, which is critical for insects to survive food induced toxicity. Cucurbitacin is widely present in plants such as cucumber and gourds that acts as an anti-herbivore chemical and an insecticide. Cucurbitacin has a harmful effect on insect larvae as well. Although various beneficial effects of cucurbitacin such as alleviating hyperglycemia have also been documented, it is not clear what kinds of molecular sensors are required to detect cucurbitacin in nature. Cucurbitacin B, a major bitter component of bitter melon, was applied to induce action potentials from sensilla of a mouth part of the fly, labellum. Here we identify that only Gr33a is required for activating bitter-sensing gustatory receptor neurons by cucurbitacin B among available 26 Grs, 23 Irs, 11 Trp mutants, and 26 Gr-RNAi lines. We further investigated the difference between control and Gr33a mutant by analyzing binary food choice assay. We also measured toxic effect of Cucurbitacin B over 0.01 mM range. Our findings uncover the molecular sensor of cucurbitacin B in Drosophila melanogaster. We propose that the discarded shell of Cucurbitaceae can be developed to make a new insecticide.

• JSTS:Journal of Semiconductor Technology and Science
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• 제7권3호
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• pp.151-160
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• 2007

We report the label-free biomolecules detection based on nanomechanical micro cantilevers operated in dynamic mode for detection of two marker proteins (myoglobin and creatin kinase-MB (CK-MB)) of acute myocardical infarctions. When the specific binding between the antigen and its antibody occurred on the fuctionalized microcantilever surface, mechanical response (i.e. resonant frequency) of microcantilevers was changed in lower frequency range. We performed the label-free biomolecules detection of myoglobin and CK-MB antigen in the low concentration (clinical threshold concentration range) as much as 1 ng/ml from measuring the dynamic response change of micro cantilevers caused by the intermolecular force. Moreover, we estimate the surface stress on the dynamic microcantilevers generated by specific antibody-antigen binding. It is suggested that our dynamic microcantilevers may enable one to use the sensitive label-free biomolecules detection for application to the disease diagnosis system based on mechanical immuno-sensor.