• 센서학회지
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• 제16권5호
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• pp.331-336
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• 2007

In this study, we have fabricated an infrared optical fiber based sensor which can monitor the respiration of a patient. The design of a chalcogenide optical fiber based sensor is suitable for insertion into a high electro-magnetic field environment because the sensor consists of low cost and compact mid-infrared components such as an infrared light source, a chalcogenide optical fiber and a thermopile sensor. A fiber-optic respiration sensor is capable of detecting carbon dioxide ($CO_{2}$) in exhalation of a patient using the infrared absorption characteristics of carbon gases. The modulated infrared radiation due to the presence of carbon dioxide is guided to the thermopile sensor via a chalcogenide receiving fiber. It is expected that a mid-infrared fiber-optic respiration sensor which can be developed based on the results of this study would be highly suitable for respiration measurements of a patient during the procedure of an MRI.

• 센서학회지
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• 제29권5호
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• pp.303-311
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• 2020

Nondispersive infrared CO₂ gas sensor was developed after the simulation of optical cavity structure and assembling the optical components: IR source, concave reflectors, Fresnel lens, a hollow disk, and IR detectors. By placing a hollow disk in front of reference IR detector, the output voltages are almost constant value, near to 70.2 mV. The absorbance of IR light, F_a, shows the second order of polynomial according to ambient temperatures at 1,500 ppm. The differential output voltages and the absorbance of IR light give a higher accuracy in estimations of CO₂ concentrations with less than ± 1.5 % errors. After implementing the parameters that are dependent upon the ambient temperatures in microcontroller unit (MCU), the measured CO₂ concentrations show high accuracies (less than ± 1.0 %) from 281 K to 308 K and the time constant of developed sensor is about 58 sec at 301 K. Even though the estimation errors are relatively high at low concentration, the developed sensor is competitive to the commercial product with a high accuracy and the stability.

• 센서학회지
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• 제14권5호
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• pp.337-342
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• 2005

A silicon-based micro-reactor to amplify small amount of deoxyribonucleic acid (DNA) has been fabricated using micro-electro-mechanical systems (MEMS) technology. Polymerase chain reaction (PCR) of DNA requires a precise and rapid temperature control. A Pt sensor is integrated directly in the chamber for real-time temperature measurement and an infrared lamp is used as external heating source for non-contact and rapid heating. In addition to the real-time temperature sensing, PCR needs a rapid thermocycling for effective PCR. For a fast thermal response, the thermal mass of the reactor chamber is minimized by removal of bulk silicon volume around the reactor using double-side KOH etching. The transparent optical property of silicon in the infrared wavelength range provides an efficient absorption of thermal energy into the reacting sample without being absorbed by silicon reactor chamber. It is confirmed that the fabricated micro-reactor could be heated up in less than 30 sec to the denaturation temperature by the external infrared lamp and cooled down in 30 sec to the annealing temperature by passive cooling.

• 한국재료학회지
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• 제26권2호
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• pp.100-108
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• 2016

Zinc Sulfide (ZnS) is one of the II-VI semiconducting materials, having novel fundamental properties and diverse areas of application such as light-emitting diodes (LEDs), electroluminescence, flat panel displays, infrared windows, catalyst, chemical sensors, biosensors, lasers and biodevices, etc. However, despite the remarkable versatility and prospective potential of ZnS, research and development (R&D) into its applications has not been performed in much detail relative to research into other inorganic semiconductors. In this study, based on global patent information, we analyzed recent technical trends and the current status of R&D into ZnS applications. Furthermore, we provided new technical insight into ZnS applicable fields using in-depth analysis. Especially, this report suggests that ZnS, due to its infrared-transmitting optical property, is a promising material in astronomy and military fields for lenses of infrared systems. The patent information analysis in this report will be utilized in the process of identifying the current positioning of technology and the direction of future R&D.

• 비파괴검사학회지
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• 제22권6호
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• pp.609-620
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• 2002

It is well known that during tensile testing, a part of the mechanical work done on the specimen is transformed into heat energy. However, the ultimate temperature rise and the rate of temperature rise is related to the nature of the material, conditions of the test and also to the deformation behaviour of the material during loading. The recent advances in infrared sensors and image/data processing techniques enable observation and quantitative analysis of the heat energy dissipated during such tensile tests. In this study, infrared imaging technique has been used to characterise the tensile deformation in AISI type 316 nuclear grade stainless steel. Apart from identifying the different stages during tensile deformation, the technique provided an accurate full-field temperature image by which the point and time of strain localization could be identified. The technique makes it possible to visualise the region of deformation and failure and also predict the exact region of fracture in advance. The effect of thermal gradients on plastic flow in the case of interrupted straining revealed that the interruption of strain and restraining at a lower strain rate not only delays the growth of the temperature gradient, but the temperature rise per unit strain decreases. The technique is a potential NDE tool that can be used for on-line detection of thermal gradients developed during extrusion and metal forming process which can be used for ensuring uniform distribution of plastic strain.

• 센서학회지
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• 제28권4호
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• pp.256-261
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• 2019

In this study, mid-infrared transparent zinc sulfide (ZnS) ceramics were fabricated through hydrothermal synthesis with different molar ratios of S/Zn (S/Zn = 0.8, 1.0, 1.2, 1.4, and 1.6). The ZnS ceramics were sintered at a relatively low temperature of $850^{\circ}C$ to prevent the occurrence of the hexagonal phase featuring optical anisotropy. The phase composition, microstructure, and optical properties of the ZnS ceramics were subsequently investigated by employing X-ray diffraction, scanning electron microscopy, and Fouriertransform infrared spectroscopy. The results obtained indicate that the ZnS nanoparticles feature the cubic phase, without the hexagonal phase. Moreover, with increasing S, the crystallinity and particle size of the ZnS nanoparticles increased. The crystallinity and density of the ZnS ceramics improved when the molar ratio of S was higher than the molar ratio of Zn, thereby enhancing the transmittance. Furthermore, the ZnS ceramic with an S/Zn value of 1.2 was found to exhibit the highest transmittance of approximately 69% owing to the reduced occurrence of the hexagonal phase and a high density of 99.8%.

• 센서학회지
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• 제28권2호
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• pp.101-105
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• 2019

ZnS substrates with excellent transmittance in the mid-infrared region ($3-5{\mu}m$) were prepared using hot pressing instead of conventional chemical vapor deposition (CVD). Diamond-like carbon(DLC) was coated on either one or both sides of the ZnS substrates to improve their mechanical properties and transmittance. More specifically DLC was coated using CVD with an Ar and $C_2H_2$ mixed gas, and Ge was used as the bonding layer. During CVD, the bias voltage was fixed to 500 V and analyzed by Fourier transform infrared spectroscopy (FT-IR), nanoindenter, scanning electron microscope and energy dispersive spectrometry. Results of hardness analysis using the nanoindenter, showed that DLC coating increased from 5.9 to 17.7 GPa after deposition. The FT-IR spectroscopy results showed that, in the mid-infrared region ($3-5{\mu}m$), the average transmittance of the samples with DLC coating on one and both sides increased by approximately 6% and approximately 11.2% respectively. In conclusion, the DLC coating improved the durability and transmittance of the ZnS substrates.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2005년도 추계종합학술대회
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• pp.781-784
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• 2005

Twenty four types of thermopile for micro spectrometer infrared sensors were fabricated on low-stress $Si_3N_4$ membranes with $1.2{\mu}m-thickness$ using MEMS technology. Poly-Si thin film with thickness of 3500 ${\AA}$ as the first thermocouple material, was deposited by LPCVD method. And aluminum thin film with thickness of 6000 ${\AA}$ as the second thermocouple material, was deposited by sputtering method. Thermopile were designed and fabricated for optimum conditions by five parameters of thermocouple numbers (16 ${\sim}$ 48), thermocouple line widths (10 ${\mu}m$ ${\sim}$ 25 ${\mu}m$), thermocouple lengths (100 ${\mu}m$ ${\sim}$ 500 ${\mu}m$), membrane areas ($1^2\;mm^2$ ${\sim}$ $2.5^2\;mm^2$) and junction areas (150 ${\mu}m^2$ ${\sim}$ 750 ${\mu}m^2$), respectively. Electromotive forces of fabricated thermopile were measured 1.1 mV ${\sim}$ 7.4 mV at $400^{\circ}C$. It was thought that measurement results could be used for thermopile infrared sensors optimum structure for micro spectrometers.

• 한국통신학회논문지
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• 제33권11B호
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• pp.1005-1012
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• 2008

전 세계적으로 노령 인구가 급속하게 증가함에 따라 그 어느 분야보다 실버 케어 분야의 필요성이 증대되고 있다. 본 논문에서는 보호자가 피보호자의 상태를 실시간으로 모니터링 할 수 있고, 위급 상황을 보호자 및 의료기관에 통보 할 수 있는 고령 환자 케어 시스템을 설계하고 구현한다. 제안된 시스템은 노령 환자들의 활동량을 분석하고 움직임을 감지하기 위한 기능을 RFID와 적외선 센서에 임베디드로 구현하고, 홈 게이트웨이는 미들웨어 표준인 OSGi를 이용해 다양한 이기종 장비들과 쉽게 통합할 수 있도록 하였다. 구현된 시스템을 통해 피보호자의 일일 활동량 및 주간 활동량 정보는 웹브라우저를 통해서 확인이 가능하며, 웹캠을 통한 영상도 실시간으로 볼 수 있다. 또한 위급한 상황 발생 시 보호자의 휴대전화와 이메일로 이러한 정보가 통지될 수 있다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2009년도 춘계학술대회 논문집
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• pp.418-423
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• 2009

대부분의 역사에 개찰구와 매표소가 구비되어 있거나 탑승 검표원이 드문 국내 철도 시스템과는 달리 해외의 경우, 버스 혹은 철도차량의 각 출입문 근처에 압력센서 발판 혹은 적외선 센서 그리고 CCTV 카메라를 이용한 승객 계수 시스템이 이용 되어져 왔다. 이러한 승객 계수 시스템에 의해 수집된 정보는 요일별, 시간대별 그리고 정류소별 차량 승하차 승객 수 파악을 위한 솔루션을 제공함으로써 대규모의 차량 운영사로 하여금 효율적인 차량배치 및 불필요한 인력낭비 방지를 통한 이익창출을 가능케 할 것으로 예상된다. 본 논문에서는 철도차량 출입문 근처에 적외션 센서를 장착하여 차량 승하차 승객수를 계산하는 시스템의 특정 및 무선망 (GPS, WLAN, Cellular)과 연동시 제공되는 기타 기능들에 대해 서술하였다.