• 비파괴검사학회지
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• 제35권1호
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• pp.12-17
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• 2015

본 연구에서는 기존의 열영상 측정 장치에 비해 위상잠금기법을 채용한 열영상 측정 장치의 온도분해능이 얼마나 향상될 수 있는지를 평가하기 위해 흑체시스템과 마이크로 레지스터 시편을 이용한 실험을 수행하여 개선된 온도분해능을 확인하였다. 일반적으로 적외선 열영상 측정 장치의 노이즈 수준 또는 온도분해능은 연속적으로 측정된 열영상의 픽셀별 온도의 평균과 각각의 측정값의 편차에 대한 제곱의 평균으로 정의되는 잡음등가온도차(noise equivalent temperature difference, NETD)라는 척도를 이용하여 평가되고 있다. 하지만 위상잠금 열영상 기법을 적용하면 더욱 편리한 방법을 이용할 수 있는데 이는 측정된 열영상 신호의 위상과는 무관한 온도의 진폭에 관한 정보를 이용하는 것이다. 연구결과를 통해 알 수 있듯이, 위상잠금 기법을 적용하게 되면 측정된 신호의 온도분해능 성능을 보여주는 잡음등가온도차가 크게 향상되었으며 이는 위상잠금기법이 내부적으로 수행하는 평균화 작업과 필터링 기능 때문인 것으로 판단되고 있다.

• 한국정밀공학회지
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• 제27권8호
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• pp.76-83
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• 2010

Metallic sandwich panels with pyramidal truss structures are high-stiffness and high-strength materials with low weight. In particular, bulk structures have enough space for additional multi-functionalities. In this work, in order to fabricate 3-D structures efficiently, Layered Manufacturing Method (LMM) which was composed of three steps, including crimping process, stacking process and bonding process using rapid infrared brazing, was proposed. The joining time was drastically reduced by employing infrared brazing of which heating rate and cooling rate were faster than those of conventional furnace brazing. By controlling the initial cooling rate slowly, the bonding strength was improved up to the level of strength by conventional vacuum brazing. The observation of infrared brazed specimens by optical microscope and SEM showed no defect on the joining sections. The experiments of 1-layered pyramidal structures and 2-layered pyramidal structures subject to 3-point bending were conducted to determine structural advantages of multilayered structures. From the results, the multi-layered structure has superior mechanical properties to the single-layered structure.

• 한국세라믹학회지
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• 제27권5호
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• pp.631-637
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• 1990

Lithium fluolide single crystals were grown by a floating zone method, with infrared radiation convergence type heater, which is free of contamination from the crucible wall. The crystals grown by this apparatus are 5cm in length and 5-6mm in diameter. The grown cryatal was examined by an optical microscope, XRD, Laue camera, Vickers hardness tester, and FTIR.

• 세라미스트
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• 제10권3호
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• pp.55-66
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• 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.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2004년도 추계학술대회 논문집
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• pp.467-470
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• 2004

Diamond-Like Carbon (DLC) thin film is a semiconductor with high mechanical hardness, low friction coefficient, high chemical inertness, and optical transparency. DLC thin films have widespread applications as protective coatings and solid lubricant coatings in areas such as Hard Disk Drive (HDD) and Micro-Electro-Mechanical-Systems (MEMS). In this work, the wear characteristics of DLC thin films deposited on silicon substrates using a DC-magnetron sputtering system were analyzed. The wear tracks were measured with an Atomic Force Microscope (AFM). To identify the sp2 and sp3 hybridization of carbon bonds and other bonds Raman spectroscopy was used. The structural information of DLC thin films was obtained with Fourier transform infrared spectroscopy and wear tests were conducted by using a micro-pin-on-reciprocator tester. Results showed that the wear characteristics were dependent on the sputtering conditions. The wear rate could be correlated with the bonding state of the DLC thin film.

• 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.

• 접착 및 계면
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• 제23권1호
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• pp.8-16
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• 2022

본 연구에서는 폴리올의 혼합으로 폴리우레탄의 물성 저하를 보완하고자 하였다. 신발 및 소재 코팅용으로서 자가치유 기능을 가지는 수분산 폴리우레탄 수지를 합성하기 위해 내구성 및 내열성이 우수한 polyether 폴리올과 기계적 물성이 뛰어난 polycarbonate 폴리올을 병용하여 합성하였으며, 자가치유 기능의 부여를 위해 disulfide기를 도입하였다. 합성된 자가치유 기능 수분산 폴리우레탄은 fourier transform-infrared spectroscopy (FT-IR)을 통해 확인되었으며, universial testing machine (UTM)과 scanning electron microscope (SEM) 측정을 통해 물리적 특성 및 자가치유 특성을 확인하였다. Polycarbonate 폴리올을 병용함으로써 인장강도 및 경도가 증가하였고, 신장율은 감소하였다. 또한 열적 특성의 비교 결과, polycarbonate 폴리올의 함량이 증가함에 따라 열 안정성이 증가하였다. 치료효율은 poly(tetramethylene ether)glycol : polycarbonate polyol = 0.75 : 0.25일 때 가장 높은 효율을 보여주었으며, 현미경 및 SEM을 이용한 표면 관찰을 통해 손상 부분이 치유된 것을 확인하였다.

• 한국산학기술학회논문지
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• 제12권2호
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• pp.999-1004
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• 2011

폭발법으로 얻어진 나노다이아몬드가 용매 내에 균일하게 분산되고, 일정 시간 침강이 이루어지지 않고 유지할 수 있도록 하고자, 표면에 카르복시기, 하이드록시기, 아민기 등의 기능기를 형성시킴으로써 나노다이아몬드의 활용성을 증대시키고자 하였다. 화학반응을 통하여 표면에 형성된 기능기, 입자의 크기 모양 등의 확인은 적외선흡수 스펙트럼과, X레이회절, 전자현미경, 원자현미경으로 관찰하였고, 용매의 종류에 따른 분산 특성을 조사하였다.

• Journal of Ceramic Processing Research
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• 제13권spc2호
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• pp.304-307
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• 2012

Nano-fibers of LiFePO4 were synthesized from a metal oxide precursor by adopting electrospinning method. After calcination of the above precursor nano-fibers at 800 ℃, LiFePO4 nano-fibers with a diameter of 300 ~ 800 nm, were successfully obtained. Measurement were performed using X-ray diffraction (XRD), fourier transform infrared spectrometer (FT-IR), videoscope, scanning electron microscope (SEM) and atomic force microscope (AFM), respectively, were performed to characterize the properties of the as-prepared materials. The results showed that the crystalline phase and morphology of the fibers were largely influenced the starting materials and electrospinning conditions.

• 보존과학회지
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• 제5권2호
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• pp.45-50
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• 1996

Silk fibers excavated at Fujinoki mounted tomb, Shimoikeyana mounted tomb and Kuriyama site were examined using FT-IR microscope and two peaks called amide I and II present in modern silk fibers were compared with those of excavated fibers. It was found that amide ground in a polymer molecule decreased with the progress of degradation and peak intensity of amide group in infrared spectrum decreased correspondingly. The advantages of FT-IR microscopy for the analysis of organic remains in archaeological view point were evaluated and it was concluded that the systematic investigation of spectral change due to the degradation of respective material is essential.