• Journal of IKEEE
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• v.23 no.1
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• pp.295-301
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• 2019

A heater in a portable real-time polymerase chain reaction(PCR) system is one of the important factors for controlling the PCR thermocycle precisely. Since heaters are integrated on a small-sized PCR chip for rapid heating and fabricated by semiconductor processes, the cost of producing PCR chips is high. Here, we propose to use chip resistors as an inexpensive and accurate temperature control method. The temperature distribution was simulated using one or two chip resistors on a real-time PCR chip and the PCR chip with uniform temperature distribution was fabricated. The temperature rise and fall rates were $18^{\circ}C/s$ and $3^{\circ}C/s$, respectively.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.11a
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• pp.267-268
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• 2006

전력소모를 감소시키기 위해 MEMS 기술을 이용하여 마이크로 히터를 제작하고 그 위에 감지물질을 도포하여 마이크로 센서를 제작하였다. 마이크로 가스센서는 $SnO_2$를 모물질로 하였으며 가스 감도를 향상시키기 위해 Pd와 Rh, ${\alpha}-Fe_2O_5$, $V_2O_5$를 첨가하여, CO 가스 강도를 조사하였다. $SnO_2$에 촉매로서 Pd만을 첨가하였을 때보다 Rh, ${\alpha}-Fe_2O_5$. $V_2O_5$등을 첨가하였을 때 CO가스에 대한 감도 반응이 우수하였다. 마이크로 가스센서의 소비전력은 42mW이었다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.9 no.3
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• pp.595-600
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• 2005

A micro flow sensor on silicon substrate allows the fabrication of small components where many different functions can be integrated so that the functionality of the sensors can be increased. Further more, the small size of the elements these sensors can be quite fast. A thermal mass flow sensor measures the asymmetry of temperature profile around the heater which is modulated by the fluid flow. In normal, a mass flow sensor is composed of a central heater and a pair of temperature sensing elements around the heater A new 2-D wide range micro flow sensor structure with three pairs of temperature sensors and a central heater was proposed and numerically simulated by Finite Difference formulation to confirm the feasibility of the flow sensor structure in time domain.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• v.9 no.1
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• pp.363-366
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• 2005

A micro flow sensor on silicon substrate allows the fabrication of small components where many different functions can be integrated so that the functionality of the sensors can be increased. Further more, due to the small size of the elements the sensors can be quite fast. A thermal mass flow sensor measures the asymmetry of temperature profile around the heater which is modulated by the fluid flow. In normal, a mass flow sensor is composed of a central heater and a pair of temperature sensing elements around the heater. A new 2-D wide range micro flow sensor structure with three pairs of temperature sensors and a central heater was proposed and numerically simulated by the Finite difference formulation to confirm the feasibility of the flow sensor structure.

• Proceedings of the KIEE Conference
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• 2006.07c
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• pp.1645-1646
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• 2006

Micro ElectroMechanical Systems (MEMS) 기술을 이용한 초미세 유체 제어 시스템 (마이크로 펌프, 마이크로 밸브, 마이크로 채널, 마이크로 믹서 등)은 화학, 생명분야의 DNA 분석, 항원-항체 분석, 질병의 진단 등에 사용되는 lab-on-a-chip, micro total analysis system ($\mu$-TAS) 등에서 화학 및 바이오 유체를 제어하는 분석 시스템의 일부분으로서 사용되며 필수적으로 요구된다. 본 논문에서는 이러한 microchip을 구현하기 위해 초미세 유체 제어 소자인 마이크로 펌프와 밸브를 같은 기관 위에 polydimethylsiloxane (PDMS)와 indium tin oxide (ITO)-Glass를 사용하여 동일한 구조로 집적 하였다. 마이크로 펌프의 pumping rate은 인가 직류 펄스 전력의 주파수와 duty 비를 변화시켜 최적화하였다. 직류 펄스 전력 500 mW를 인가하였을 때 주파수 2 Hz, duty 비 7 %에서 약 $1.05{\mu}l/min$의 최대 유량이 측정되었다. 마이크로 밸브는 ITO 히터에 전력을 인가함으로서 유량의 on/off 제어가 잘 됨을 확인할 수 있었고 유체를 closing하기 위해 필요한 전력은 약 300 mW이다.

• Proceedings of the KSME Conference
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• 2007.05b
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• pp.1870-1875
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• 2007

The microchannel heat sink is promising heat dissipation method for high heat flux source. Contrary to conventional circular channel, MEMS based microchannel had rectangular or trapezoidal cross-sectional shape. In our study, we conducted three dimensional conjugate heat transfer calculation for rectangular shape microchannel. First, we simulated that channel was completely drained with known heating power. As a result we obtained calibration line, which indicates heat loss was function of temperature. Second, we simulated single phase heat transfer with various mass flux, 100-400 $kg/m^2s$. In conclusion, the single phase test verified that the present heat loss evaluation method is applicable to micro scale heat transfer devices. Heat fluxes from each side wall shows difference due to non-uniform heating. However those ratios were correlated with supplied total heat. Finally, we proposed effective area correction factor to evaluate appropriate heat flux.

• Proceedings of the KSME Conference
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• 2004.11a
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• pp.1225-1230
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• 2004

The effects of substrate material on the local heating performance of microheaters are studied by both numerical analysis and experiment. Transient conduction analysis shows that the substrate material with low thermal conductivity is critical to the local heating and fast response. A measurement technique for surface temperature field in microscale is newly proposed, which uses temperature sensitive fluorescent dye coated on the surface. The measured surface temperature fields on microheater arrays fabricated on different substrates are presented.

• Proceedings of the KSME Conference
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• 2004.11a
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• pp.1353-1358
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• 2004

An experimental study of pool boiling behavior on micro-porous enhanced square heater surfaces immersed in PF5060 is performed. The effects of heater orientation, Subcooling and substrate distance on the pool boiling heat transfer performance for the double heaters were investigated under increasing heat-flux conditions. The boiling performance of micro-porous coated surface was better than that of plain surface. The double heaters with upper substrate of 0.2cm substrate interval have lower boiling performances compared with the results for the double heaters with that of 0.5cm and 1.0cm substrate interval and without the substrate. In comparison to upper heater and below heater with orientation, the upper heater has lower superheat temperature than the below heater due to the bubble sweeping.

• Electronics and Telecommunications Trends
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• v.23 no.6
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• pp.48-58
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• 2008

에너지 하베스팅 기술은 자연의 빛에너지, 인간 신체 또는 연소형 엔진으로부터의 저온 폐열에너지, 휴대용 기기 탑재/부착장치의 미세 진동에너지, 인간의 신체활동(걷거나 뛰는)으로 인한 소산에너지 등을 흡수하여 에너지 하베스팅 소자 기술을 이용하여 전기에너지로 변환, 전자 기기의 전력으로 사용하는 환경에너지 재생형 에너지원이라 할 수 있다. 유비쿼터스의 정보화 시대에는 휴대형 정보기기 등이 필수적인 기기가 될 것인데 여기에 사용되는 전력 에너지원은 소형.집적화된 기술이 필수적이다. 이때 MEMS 기술은 에너지 하베스팅 기술의 소형.집적화 기술에 크게 기여하고 극복해야 할 기술에 핵심적인 기술로 사용된다. MEMS 기술이 사용되는 대표적인 에너지 하베스터 기술인 마이크로 연료전지, 마이크로 히터 엔진, Piezoelectric MPG 기술 등을 소개하였다.

• Journal of the Microelectronics and Packaging Society
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• v.28 no.4
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• pp.73-77
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• 2021

Flexible electrodes for wearable devices have been actively studied in not only achieving mechanical/electrical stability, but also providing various functionalities for extending its industrial application. In this study, a flexible carbon/PDMS composite is prepared by addition of carbon black (CB) as a conductive filler, and effect of CB with different contents on electrical properties of the composite was investigated for the application of flexible electrodes, temperature sensor and heater. With increase of CB contents, resistivity of the carbon/PDMS was increased, and excellent durability was observed, confirmed by repetitive stretching deformation test. Resistance increase of the carbon/PDMS with temperature reveals the property of positive temperature coefficient, which can be applied for temperature sensor. Also, joule heating on the carbon/PDMS was observed when electrical potential was applied, indicating the applicability of the carbon/PDMS for heater.