• 한국항공우주학회지
• /
• 제42권8호
• /
• pp.640-647
• /
• 2014

추진기관 배기 플룸의 적외선 복사(Infrared radiation :IR) 신호는 항공기 생존성에 영향을 미치는 주요 요인이다. 항공기의 생존성 향상을 위해 IR 감소 설계 기술이 적용된 추진기관의 정확한 IR 신호 예측이 필요하다. 본 연구는 유동 및 열전달 해석 코드를 이용하여 노즐 내부, 외부 자유류, 플룸 영역의 열유동장을 수치 해석하였다. 비회색가스의 특성을 효율적으로 해석하는 좁은밴드 기반의 재조합 회색가스가중합법을 적용하여 항공기 플룸에서 방사되는 파장별 IR 신호를 계산하였다. 개발된 프로그램의 정확성과 신뢰성을 확보하고자 1차원 모델에 대한 검증을 거친 후 항공기 추진기관의 열유동장 및 파장별 IR 신호 해석을 수행하였다. 해석을 통하여 상대적으로 플룸 내부에서 IR 복사강도가 높은 것을 확인하였고 온도, 분압, 화학종에 따라 다른 파장별 IR 신호 특성을 파악하였다. 노즐 출구 부근에서는 노즐 벽면의 고체 방사로 인하여 파장별 IR 복사강도가 연속적으로 나타났다.

• 한국통신학회논문지
• /
• 제26권12B호
• /
• pp.1695-1702
• /
• 2001

본 논문에서는 4 Mb/s 부터 100 Mb/s 의 IrDA(Infrared Data Association) 응용이 가능한 CMOS infrared (IR) wireless data link IC의 설계 방법에 대해 기술한다. 이 모듈은 60 dB에서 100 dB가지의 이득 범위를 가지는 variable gain transimpedance amplifier, AGC(automatic gain control) 회로, AOC(automatic offset control) loop, 4 PPM (pulse position modulation) modulator/demodulator와 DLL(delay locked loops)로 구성된다. 본 적외선 광송수신 IC는 0.25 um 1-poly 5-metal CMOS 공정을 이용하여 제작되었다. 2.5 V 전원 전압에서 동작시켰으며 100 Mb/s에서 출력단 버퍼를 제외하고 25 mW의 진력을 소모한다. 칩의 크기는 1.5 mm $\times$ 1 mm이다.

• 센서학회지
• /
• 제29권5호
• /
• pp.303-311
• /
• 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.

• 한국항공우주학회지
• /
• 제41권10호
• /
• pp.779-787
• /
• 2013

항공기 추진 시스템의 IR 피탐지성 감소 연구를 위해 항공기 노즐형상 변화에 따른 IR 신호의 영향성을 연구하였다. 이를 위해 가상의 아음속 무인기를 선정하고, 임무분석 및 성능 해석을 통해 엔진을 결정한 후 전체 임무를 만족시키는 원형 노즐을 설계하였다. 또한 다수의 설계변수를 적용하여 다양한 형상의 노즐을 설계하였다. 압축성 CFD 코드를 이용하여 열유동장 및 노즐표면 온도를 분석하였다. 또한 열유동장 해석 결과를 바탕으로 narrow-band 모델과 RadThermIR을 기반으로 하여 항공기 플룸 및 노즐표면 IR 신호를 계산하였다. 계산된 플룸 및 고체 IR신호를 분석, 비교하여 항공기 IR 신호 특성에 관한 정성적 정보를 도출하였다.

• 한국재료학회지
• /
• 제13권10호
• /
• pp.697-702
• /
• 2003

FT-IR and thermograph were used to investigate the infrared radiation characteristics of $SiO_2$film made by the sol-gel method. FT-IR spectrum of the $SiO_2$film showed high infrared absorption by Si-O-Si vibration at 1220, 1080, 800 and cm$460^{-1}$ The infrared absorption and radiation wavelength ranges of the $SiO_2$film measured by the integration method coincided with the reflection method, and the infrared emissivity was 0.65, equally. Depending on the bonding of elements, the infrared emissivity was high in the wavelength range where the infrared absorption rate was high, that follows the Kirchhoff's law. The emissivity showed the highest value in the wavelength range between $8∼10\mu\textrm{m}$. $SiO_2$film was considered as an efficient materials for infrared radiator at temperature below 10$0^{\circ}C$. The heat radiation temperature was $117^{\circ}C$ for the aluminum plate, but $146^{\circ}C$ for the $SiO_2$film after 7 minutes heat absorption, consiquently, $29^{\circ}C$ higher than the former.

• 한국산업융합학회 논문집
• /
• 제27권1호
• /
• pp.57-62
• /
• 2024

This study conducted a measurement method of high temeprature conditions using infrared termography. All objects emit infrared light, and this emissivity has a significant impact on the temperature measurements of infrared thermal imaging (IR) cameras. In order to measure the temperature more accurately with the IR camera, correction equations were derived by measuring the emissivity according to the temperature change of combustible metals in a high-temperature environment. Two combustible metals, Mg and Al, were used to measure emissivity with changing temperature. Each metal was heated, the emissivity was measured by comparing the temperature with IR camera and thermocouples so that the correlation between temperature and emissivity could be anslyzed. As a result of the experiment, the emissivity of the metals increases as the temperature increased. This can be interpreted as a result of increased radiation emission as the thermal movement of internal metal molecules increased.

• 세라미스트
• /
• 제10권3호
• /
• pp.55-66
• /
• 2007

Infrared Scanning Near-field Optical Microscopy (IR-SNOM) is an extremely powerful analytical instrument since it combines IR spectroscopy's high chemical specificity with SNOM's high spatial resolution. In order to do this in the infrared, specialty chalcogenide glass fibers were fabricated and their ends tapered to generate SNOM probes. The fiber tips were installed in a modified near field microscope and both inorganic and biological samples illuminated with the tunable output from a free-electron laser located at Vanderbilt University. Both topographical and IR spectral images were simultaneously recorded with a resolution of ${\sim}50\;nm$ and ${\sim}100\;nm$, respectively. Unique spectroscopic features were identified in all samples, with spectral images exhibiting resolutions of up to ${\lambda}/60$, or at least 30 times better than the diffraction limited lens-based microscopes. We believe that IR-SNOM can provide a very powerful insight into some of the most important bio-medical research topics.

• 센서학회지
• /
• 제26권2호
• /
• pp.91-95
• /
• 2017

Recently, infrared (IR) spectrometers have been required in various fields such as environment, safety, mobile, automotive, and military. This IR dispersive sensor detection method of substances is widely used. In this study, we fabricated a silicon (Si) prism-based near infrared (NIR) spectrometer utilizing micro electro mechanical system (MEMS) technology. Si prism-based NIR spectrometer utilizing MEMS technology consists of upper, middle, and lower substrates. The upper substrate passes through the incident IR ray selectively. The middle substrate, acting as a prism, disperses and separates the incident IR beam. The lower substrate has an amorphous Si (a-Si)-based bolometer array to detect the IR spectrum. The fabricated Si prism-based NIR spectrometer utilizing MEMS technology has the advantage of a simple structure, easy fabrication steps, and a wide NIR region operating range.

• 한국진공학회지
• /
• 제17권3호
• /
• pp.215-219
• /
• 2008

실리콘 웨이퍼 위에 Plasma Enhanced Chemical Vapor Deposition (PECVD) 방법으로 증착 된 SiNx 박막의 수소 함량을 측정하였다. 제작된 SiNx 박막은 Fourier Transform Infrared Spectroscopy (FT-IR) 사용하여 박막의 수소함량과 결합상태를 확인하였으며, Atomic Force Microscopy (AFM) 측정을 통하여 박막의 표면 거칠기를 비교, 시료의 조성비 평가를 위하여 Rutherford Backscattering Spectrometry (RBS)을 사용하였다. 또한 SiNx박막의 조성확인을 위하여 Photoluminescence(PL)를 이용하여 FT-IR spectrum의 결과와 비교 해석하였다. FT-IR에서 NH의 수소함량(at%)이 0.92 %에서 0.64 %로 낮아질 수록 AFM을 이용한 표면 거칠기는 12.8 $\AA$에서 10.8 $\AA$로 낮아지고, Si양이 상대적으로 많아지는 것을 PL에서 확인하였으며, RBS에서도 시뮬레이션을 통해 비슷한 결과를 얻을 수 있었는데, 이는 FT-IR을 사용함으로써 SiNx 박막의 수소 함량의 측정이 가능하다는 것을 보여주므로 단위공정에서 신속하게 SiNx 박막 분석이 가능함을 알 수 있었다.

• 반도체디스플레이기술학회지
• /
• 제18권1호
• /
• pp.5-9
• /
• 2019

Optical emission spectroscopy is used to identify chemical species and monitor the changes of process results during the plasma process. However, plasma process monitoring or fault detection by using emission signal variation monitoring is vulnerable to background signal fluctuations. IR heaters are used in semiconductor manufacturing chambers where high temperature uniformity and fast response are required. During the process, the IR lamp output fluctuates to maintain a stable process temperature. This IR signal fluctuation reacts as a background signal fluctuation to the spectrometer. In this research, we evaluate the effect of infrared background signal fluctuation on plasma process monitoring and improve the plasma process monitoring accuracy by using simple infrared background signal subtraction method. The effect of infrared background signal fluctuation on plasma process monitoring was evaluated on $SiO_2$ PECVD process. Comparing the $SiO_2$ film thickness and the measured emission line intensity from the by-product molecules, the effect of infrared background signal on plasma process monitoring and the necessity of background signal subtraction method were confirmed.