• 한국전기전자재료학회논문지
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• 제19권9호
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• pp.868-872
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• 2006

In this work, the effects of the corona treatment on surface properties of semiconducting silicone rubber were investigated in terms of contact angles, ATR-FTIR(Attenuated total reflection fourier transform infrared spectroscopy) and XPS(X-ray photoelectron spectroscopy). And the adhesive characteristics were studied by measuring the T-peel strengths. Based on chemical analysis, the surface modification can be mainly ascribed to the creation of chemically active functional groups such as C-O, C=O and C-OH on semiconducting silicone surface. This oxidized rubber layer is inorganic silica-like structure of Si bound with three to four oxygen atoms ($SiOx,\;x=3{\sim}4$. The Corona treatment produces an increase in joint strength that is maximum for 10 min treatment. However, due to brittle property of this oxidized layer, the highly oxidized layer from too much extended treatment could be act as a weak point, decreasing the adhesion strength.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2017년도 춘계학술대회
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• pp.733-734
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• 2017

위치정보를 얻기 위하여 초음파, 적외선, CCD카메라 등이 대표적으로 사용되고 있지만 주변 환경에 따라 오차가 범위가 크다 하지만 IR-UWB는 실내 외에서도 거리와 위치측정이 가능하여 차세대 측위기술로 주목을 받고 있는 기술이다. 1ns 단위로 짧은 신호 폭을 방사하고 반사되어 수신되는 신호와 시간적 지연을 이용하여 물체의 존재와 거리를 판단할 수 있다. 또한 주변 환경 조건과 상관없이 cm의 오차내의 정확한 위치측정이 가능하다. 수많은 반사 신호를 처리하기 때문에 각종 잡음을 신호의 평균값, Band pass Filter와 FFT를 이용하여 잡음을 개선하여 3차원 공간좌표를 분석하려 한다.

• 한국전기전자재료학회논문지
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• 제16권8호
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• pp.700-704
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• 2003

This paper describes on characteristics of 2" 3C-SiC wafer bonding using PECVD (plasma enhanced chemical vapor deposition) oxide and HF (hydrofluoride acid) for SiCOI (SiC-on-Insulator) structures and MEMS (micro-electro-mechanical system) applications. In this work, insulator layers were formed on a heteroepitaxial 3C-SiC film grown on a Si (001) wafer by thermal wet oxidation and PECVD process, successively. The pre-bonding of two polished PECVD oxide layers made the surface activation in HF and bonded under applied pressure. The bonding characteristics were evaluated by the effect of HF concentration used in the surface treatment on the roughness of the oxide and pre-bonding strength. Hydrophilic character of the oxidized 3C-SiC film surface was investigated by ATR-FTIR (attenuated total reflection Fourier transformed infrared spectroscopy). The root-mean-square suface roughness of the oxidized SiC layers was measured by AFM (atomic force microscope). The strength of the bond was measured by tensile strength meter. The bonded interface was also analyzed by IR camera and SEM (scanning electron microscope), and there are no bubbles or cavities in the bonding interface. The bonding strength initially increases with increasing HF concentration and reaches the maximum value at 2.0 ％ and then decreases. These results indicate that the 3C-SiC wafer direct bonding technique will offers significant advantages in the harsh MEMS applications.ions.

• 대한기계학회논문집A
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• 제31권2호
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• pp.253-259
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• 2007

A new material tester has been developed to measure mechanical properties of thin film specimens at high temperature. It is useful for observing oxide film growth or local deformation on the surface, and for measuring creep strength. Main characteristics of the tester is as follows; First, high temperature is achieved by Joule heating generated by electricity passing through the specimen, which does not need to enclose the specimen by a furnace or a heating chamber. The exposed specimen enables one to observe the surface during the test. Because the overall size of the test rig is compact, the whole test rig can be placed in a chamber for environmental controlled tests. The loading device is from a level scales. Not only static load with fixed counter weight, but also variable load by moving counter weight controlled remotely can be applied for an ordinary creep test and creep-fatigue test, respectively. The detail of the construction, operation principle, and the specification are described. And also, an example of test result obtained using the creep tester is presented.

• Bulletin of the Korean Chemical Society
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• 제24권5호
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• pp.593-599
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• 2003

The nanoparticle magnetite of which diameter was about 3 nm was synthesized in a homogeneous aqueous solution without a template. The synthesized magnetite nanoparticle was easily oxidized to maghemite in an ambient condition. The magnetic properties of the ferrite nanoparticle show superparamagnetism at room temperature and its blocking temperature is around 93 K. Modifying the sequential adsorption method of metal bisphosphonate, we have prepared a multilayer thin film of the ferrite nanoparticle on planar substrates such as glass, quartz and Si wafer. In this multilayer the ferrite nanoparticle layer and an alkylbisphosphonate layer are alternately placed on the substrates by simple immersion in the solutions of the ferrite nanoparticle and 1, 10-decanediylbis (phosphonic acid) (DBPA), alternately. This is the first example, as far as we know, of nanoparticle/alkyl-bisphosphonate multilayer which is an analogy of metal bisphosphonate multilayer. UV-visible absorption and infrared reflection-absorption studies show that the growth of each layer is very systematic and the film is considerably optically transparent to visible light of 400-700 nm. Atomic force microscopic images of the film show that the surface morphology of the film follows that of the substrate in μm-scale image and the nanoparticle-terminated surface is differentiated from the DBPA-terminated one in nm-scale image. The magnetic properties of this ferrite/DBPA thin film are almost the same as those of the ferrite nanoparticle powder only.

• Nano
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• 제13권10호
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• pp.1850121.1-1850121.11
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• 2018

In this study, a series of $LaMnO_3$-diamond composites with varied $LaMnO_3$ mass contents supported on micro-diamond have been synthesized using a sol-gel method. The as-prepared composites were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Raman spectroscopy and the Fourier transform infrared spectra (FTIR). Meanwhile, the photocatalytic performances were also tested by photoluminescence (PL) spectroscopy, ultraviolet-visible diffuse reflection spectra (UV-Vis DRS) and the degradation of weak acid red C-3GN (RC-3GN). Results show that the peak position of $LaMnO_3$ is shifted to low angle after the introduction of diamond, and perovskite particles uniformly distributed on the surface of diamond, forming a network structure, which can increase the active sites and the absorption of dye molecules. When the mass ratio of $LaMnO_3$ and diamond is 1:2 (LMO-Dia-2), the composite shows the most excellent photocatalytic activity. This result offers a sample route to enlarge the range of the application of micro-diamond and provide a new carrier for perovskite photocatalysts.

• Current Optics and Photonics
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• 제7권3호
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• pp.254-262
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• 2023

Novel thermo-optically focus-switchable Fresnel zone plates based on phase-change metafilms are designed and analyzed at a visible wavelength (660 nm). By virtue of the large thermo-optic response of vanadium dioxide (VO₂) thin film, a phase-change material, four different plasmonic phase-change absorbers are numerically designed as actively tunable Gires-Tournois Al-VO₂ metafilms in two and three dimensions. The designed phase-change metafilm unit cells are used as the building blocks of actively focus-switchable Fresnel zone plates with strong focus switching contrast (40%, 83%) and high numerical apertures (1.52, 1.70). The Fresnel zone plates designed in two and three dimensions work as cylindrical and spherical lenses in reflection type, respectively. The coupling between the thermo-optic effect of VO₂ and localized plasmonic resonances in the Al nanostructures offer a large degree of freedom in design and high-contrast focus-switching performance based on largely tunable absorption resonances. The proposed method may have great potential in photothermal and electrothermal active optical devices for nonlinear optics, microscopy, 3D scanning, optical trapping, and holographic displays over a wide spectral range including the visible and infrared regimes.

• 방송공학회논문지
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• 제11권1호
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• pp.80-90
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• 2006

본 논문에서는 한 대의 카메라와 푸르킨예 영상을 이용한 간편한 2차원 시선 추적 시스템을 제안한다. 이 시스템은 사용자의 한쪽 눈 영상을 얻기 위해 적외선 필터가 장착된 카메라와, 사용자가 모니터 상에 바라보고 있는 응시 점을 알아내기 위해 각 막의 표면에 반사점을 만들기 위한 두 개의 적외선 광원이 사용되었다. 카메라나 적외선 광원, 사용자의 머리는 자유롭게 움직일 수 있다. 따라서 본 시스템은 여타 불편한 고정된 장치나 사용자의 머리 고정이 필요 없는 간단하고 유연성 있는 시스템이다. 본 시스템은 또한 간편하고 정확한 사용자 캘리브레이션 과정을 포함하고 있다. 시스템을 사용하기에 앞서, 각 사용자는 각 사용자는 시스템이 시선 추적 알고리즘 상의 개인 요소들을 초기화할 수 있도록 두 개의 점을 잠시 바라보기만 하면 된다. 제안된 시스템은 XGA $(1024{\sim}768)$ 해상도에서 10 fps 이상 실시간으로 동작된다. 3명의 피 실험자와 9개의 실험 물체로 진행된 실험 결과는 시스템이 평균 l도의 시선 추적 오차를 보여 주고 있다.

• Journal of the Korean Wood Science and Technology
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• 제43권3호
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• pp.304-310
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• 2015

저장 또는 운송단계에서 목분에 포함된 수분의 부적절한 조절은 생물학적 열화로 인한 품질하락 및 손실을 야기할 수 있기 때문에 목분의 함수율은 정확하게 측정되어야 하고 적절하게 조절되어야 한다. 본 연구에서는 근적외선(파장 대역: 1000-2400 nm) 분광분석법을 적용하여 낙엽송(Larix kaempferi) 목분의 함수율을 측정하고자 하였다. 각 상대습도($25^{\circ}C$, RH 30~99%) 단계별로 조습된 목분의 근적외선 반사스펙트럼을 측정하고, 적정 수학적 전처리(smoothing, standard normal variate)와 부분최소자승법을 적용하여 예측모델을 개발하였다. 도출된 함수율 예측모델은 높은 신뢰도를 보였다($R^2$ = 0.94, RMSEP = 1.544). 본 연구에서 개발된 근적외선 분광분석법을 통하여 비파괴적이면서 정확하고 신속한 목분 함수율의 측정과 효율적인 목재이용을 견인할 수 있으리라 기대된다.

• 한국식품과학회지
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• 제24권5호
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• pp.408-413
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• 1992

신속간편법으로서 식품의 성분함량 측정에 이용되는 근적외 반사분광분석에서 문제가 되고 있는 시료의 균질도의 차이가 흡광도에 미치는 영향을 조사하고 흡광도로 나타난 수치를 수학적으로 처리함으로써 예측의 오차는 다음과 같이 감소하였다. 1. 세절도가 일정한 시료의 흡광도를 무변형, 1차 미분 및 2차 미분하여 calibration한 후 세절도가 다양한 시료의 성분을 예측한 결과 예측오차(standard error of prediction)는 수분함량에 있어서 1.478%, 0.658% 및 0.580%, 지방함량의 예측오차 0.949%, 0.637%, 및 0.527%이었으며 단백질 측정시 각각 0.514%, 0.493% 및 0.394%로 2차 미분의 예측오차가 모든 성분측정에서 가장 낮음을 알 수 있었다. 2. 세절도가 다양한 시료의 무변형, 1차 미분 및 2차 미분처리한 calibration을 이용하여 세절도가 다양한 시료의 성분을 예측한 결과 수분함량 예측오차는 각각 1.026%, 0.589% 및 0.568%, 지방함량 예측오차는 각각 0.828%, 0.639% 및 0.602% 이었으며 단백질함량 예측오차는 0.860%, 0.557% 및 0.399%로서 역시 2차 미분, 1차 미분, 무변형의 순으로 정확성이 높았다. 결과를 종합할 때 흡광도를 수학적으로 처리하여 calibration에 이용하므로서 calibration시료의 세절도에 관계없이 측정결과의 정확성은 높아졌다.