• 한국전기전자재료학회논문지
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• 제23권10호
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• pp.747-751
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• 2010

In the study, the characteristics of the etched Zinc oxide (ZnO) thin films surface, the etch rate of ZnO thin film in $Cl_2/BCl_3/Ar$ plasma was investigated. The maximum ZnO etch rate of 53 nm/min was obtained for $Cl_2/BCl_3/Ar$=3:16:4 sccm gas mixture. According to the x-ray diffraction (XRD) and atomic force microscopy (AFM), the etched ZnO thin film was investigated to the chemical reaction of the ZnO surface in $Cl_2/BCl_3/Ar$ plasma. The field emission auger electron spectroscopy (FE-AES) analysis showed an elemental analysis from the etched surfaces. According to the etching time, the ZnO thin film of etched was obtained to The AES depth-profile analysis. We used to atomic force microscopy to determine the roughness of the surface. So, the root mean square of ZnO thin film was 17.02 in $Cl_2/BCl_3/Ar$ plasma. Based on these data, the ion-assisted chemical reaction was proposed as the main etch mechanism for the plasmas.

• 분석과학
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• 제13권6호
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• pp.781-788
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• 2000

수소화물 생성-유도결합플라스마 원자방출분광법(HG-ICP-AES)을 이용하여 모의사용후 핵연료(SIMFUEL) 중의 텔루르를 정량하였다. 염산과 $NaBH_4$의 농도 및 주입속도와 같은 변수들을 최적과 한 다음 각각 우라늄, 팔라듐, 루테늄, 로듐 및 몰리브덴의 간섭 정도를 조사하였다. 이들 원소, 특히 팔라듐으로부터 간섭을 줄이기 위하여 가리움제로 thiourea를 사용하였다. 모의사용후 핵연료로부터 텔루르를 양이온 교환 크로마토그래피로 분리한 다음 각각 HG-ICP-AES와 유도결합플라스마 질량분석법(ICP-MS)으로 측정하였다. 우라늄 매트릭스로부터 텔루르를 분리하지 않고 바로 전자로 측정한 결과와 분리한 다음 측정한 값의 상대편차는 ICP-MS의 결과를 기준으로 5.6%와 -1.2%이었다.

• Bulletin of the Korean Chemical Society
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• 제1권1호
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• pp.1-4
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• 1980

During the study of the kinetics of Cl atom reactions by atomic fluorescence method we observed anomalous fluorescence emission for some atomic transitions. Instead of usual decrease of the fluorescence intensity by adding substrate, 1363 A transition $(^2P^{\circ}_{3/2}{\to}^2P_{1/2})$ intensity increased by adding substrate. From the normally behaved fluorescence lines the absolute rate constant for the reaction, Cl + $CH_3Cl{\to}$, was found to be $4.2{\times}10^{-13}$ cc/molecule sec at $20^{\circ}C$.

• Bulletin of the Korean Chemical Society
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• 제16권8호
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• pp.748-754
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• 1995

• Bulletin of the Korean Chemical Society
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• 제16권9호
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• pp.894-896
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• 1995

• Geomechanics and Engineering
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• 제18권1호
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• pp.11-20
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• 2019

The purpose of this study was to propose a new approach for quantifying in situ rock mass damage, which would include a degree-of-damage and the degraded strength of a rock mass, along with its prediction based on real-time Acoustic Emission (AE) observations. The basic approach for quantifying in-situ rock mass damage is to derive the normalized value of measured AE energy with the maximum AE energy, called the degree-of-damage in this study. With regard to estimation of the AE energy, an AE crack source location algorithm of the Wigner-Ville Distribution combined with Biot's wave dispersion model, was applied for more reliable AE crack source localization in a rock mass. In situ AE wave attenuation was also taken into account for AE energy correction in accordance with the propagation distance of an AE wave. To infer the maximum AE energy, fractal theory was used for scale-independent AE energy estimation. In addition, the Weibull model was also applied to determine statistically the AE crack size under a jointed rock mass. Subsequently, the proposed methodology was calibrated using an in situ test carried out in the Underground Research Tunnel at the Korea Atomic Energy Research Institute. This was done under a condition of controlled incremental cyclic loading, which had been performed as part of a preceding study. It was found that the inferred degree-of-damage agreed quite well with the results from the in situ test. The methodology proposed in this study can be regarded as a reasonable approach for quantifying rock mass damage.

• 천문학논총
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• 제15권spc1호
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• pp.61-71
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• 2000

The emission line objects such as planetary nebulae, symbiotics, gaseous nebulae, HII regions, novae, supernovae, SNRs, nearby spiral galaxies, dIrr, dE, and nearby active galactic nuclei, would be goldmines for us to dig with the 1.8m bohyunsan optical (BOAO) telescope. We discussed the importance of strategically important diagnostic lines and atomic constant calculation for a study of Galactic and extragalactic emission objects. The scientific background on a spectrometer development history is briefly presented and spectroscopic research areas other than the emission objects are also summarized.

• 천문학회보
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• 제38권2호
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• pp.64.1-64.1
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• 2013

High energy photons and mechanical energy produced by the process of star formation result in copious FIR molecular and atomic lines, which are important coolants of the system. Photons thermally or mechanically induced could dissociate water in the dense envelope to change relative abundances among the species O, OH, and H2O. Here we analyze OH emission lines toward embedded young stellar objects (YSOs) observed as part of the Herschel open time key program, 'Dust, Ice, and Gas In Time (DIGIT)' in order to study the physical conditions of associated gas and the energy budget loaded on the OH line emission. According to our analysis of the Herschel/PACS spectra, OH emission peaks at the central spaxel in most of sources, but several sources show spatially extended emission structures. In the extended emission sources, the distribution of OH emission is correlated with that of [OI] emission and extended along the outflow directions. Considering the diversity of source properties, ratios between detected OH lines are relatively constant among sources. In addition, each OH line has strong correlation with bolometric luminosity. For detail analyses with rotation diagram and non-LTE LVG model, we present the results from GSS30-IRS1 and Elias29.

• Journal of Mechanical Science and Technology
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• 제15권12호
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• pp.1808-1815
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• 2001

The characteristics of a pulsed plasma jet originating from an electrothermal capillary discharge have been investigate using laser-induced fluorescence (LIF) measurement. Previous emission measurements of a 3.1 kJ plasma jet show trial upstream of the Mach disk the temperature and electron number density are about 14,000 K and and 10$\^$17/ cm$\^$-3/, while downstream of the Mach dick tole values are about 25,000 K and 10$\^$18/ cm$\^$-3/, respectively. However, these values are barred on line-of-sight integrated measurements that may be misleading. Hence, LIF is being used to provide both spatially and temporally resolved measurements. Our recent work has been directed at using planar laser-induced fluorescence (PLIF) imaging of atomic copper in the plasma jet flow field. Copper is a good candidate for PLIF studies because it is present throughout the plasma and has electronic transitions that provide an excellent pump-detect strategy. Our PLIF results to date show that emission measurements may give a misleading picture of the flow field, as there appeals to be a large amount of relatively low temperature copper outside the barrel shock. which may lead to errors in temperature inferred from emission spectroscopy. In this paper, the copper LIF image is presented and at the moment, relative density of atomic copper, which is distributed in the upstream of the pulsed plasma jet, is discussed qualitatively.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2011년도 제40회 동계학술대회 초록집
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• pp.83-83
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• 2011

본 연구에서는 p-type Si (100) 위에 분자선 에피택시 성장방법으로 ZnO 완충층이 삽입된 ZnO 박막을 성장시켰다. ZnO 완충층은 Zn 셀 셔터의 열림/닫힘을 반복하는 성장 멈춤법으로 성장되었다. Zn 셀 셔터의 열림 시간은 4분, 2분, 1분이며 닫힘 시간은 2분으로 동일하게 유지하였다. 이러한 과정은 각각 5, 10, 20회로 반복되었으며 ZnO 완충층을 성장한 후 ZnO 박막은 기존의 분자선 에피택시 방법으로 성장되었다. ZnO 박막의 구조적, 광학적 특성은 field-emission scanning electron microscopy (FE-SEM), atomic force microscopy (AFM), X-ray diffraction (XRD), photoluminescence (PL)로 조사하였다. SEM 측정결과 성장 멈춤 횟수가 증가함에 따라 ZnO 박막의 표면은 섬(island) 구조에서 미로(maze) 구조로 변화하였고, XRD 측정결과 full-width at half-maximum (FWHM) 이 감소하고 결정립 크기(grain size)가 증가하였다. 그리고 PL 측정결과 성장 멈춤 횟수가 증가함에 따라 near-band-edge emission (NBE) 피크의 세기가 증가하였고 deep-level emission (DLE) 피크의 위치는 오렌지 발광에서 녹색 발광으로 청색편이(blue-shift)하였다.