• 방사성폐기물학회지
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• 제16권2호
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• pp.137-164
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• 2018

심지층처분장 공학적방벽의 성능 보장은 장기처분안전성 측면에서 뿐만 아니라 심지층처분장의 효율적인 설계를 위해서도 매우 중요하다. 따라서 지하실험시설에서 수행되는 현장실험들을 통해 심지층처분장 조건 하에서의 공학적방벽 성능을 입증할 필요가 있다. 이 논문에서는 심지층처분장 공학적방벽의 성능을 실증하기 위해, 지난 수십 년 동안 전 세계에서 수행되어온 주요 현장실험의 현황과 그 결과에 대해 검토하였다. 먼저 심지층처분장의 폐쇄 후 성능을 모사하는 공학적방벽시스템의 열-수리-역학적 복합거동을 규명하기 위한 현장실험들이 분석되었다. 아울러 실제 심지층처분장의 환경에서 완충재의 성능을 조사하기 위한 현장실험들이 검토되었다. 완충재-콘크리트 상호반응, 완충재, 뒷채움재 및 플러그의 설치, 그리고 근계암반 특성과 처분용기 재질의 부식 현상을 규명하기 위한 현장실험들의 기술현황도 분석되었다.

• 한국도로학회논문집
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• 제11권2호
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• pp.85-98
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• 2009

현재, 포장시스템의 노상과 보조기층의 다짐관리는 들밀도 시험을 이용한 상대 다짐도와 평판재하시험이 널리 쓰이고 있다. 하지만, 이 두 시험법은 노상과 보조기층의 다짐관리를 평가하기엔 시간과 비용이 많이 소요되며 실측 값을 얻기에도 매우 어렵다. 이에 본 연구에서는 노상과 보조기층 시공 현장에서 다짐관리를 보다 빠르고, 적은 비용으로 측정 할 수 있는 소형충격재하시험들의 비교분석을 실시한 후, LFWD시험을 다짐평가장비로 제안하였다. 또한, 노상과 보조기층의 실내시험 및 현장 시험을 통하여 국내 도로 하부구조 재료 특성에 따른 $E_{LFWD}$와 상대 다짐도, $K_{30}$, 설계 $M_{R}$ 값과의 상관관계를 제안하였다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제42회 동계 정기 학술대회 초록집
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• pp.523-523
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• 2012

As the wafer geometric requirements continuously complicated and minutes in tens of nanometers, the expectation of real-time add-on sensors for in-situ plasma process monitoring is rapidly increasing. Various industry applications, utilizing plasma impedance monitor (PIM) and optical emission spectroscopy (OES), on etch end point detection, etch chemistry investigation, health monitoring, fault detection and classification, and advanced process control are good examples. However, process monitoring in semiconductor manufacturing industry requires non-invasiveness. The hypothesis behind the optical monitoring of plasma induced ion current is for the monitoring of plasma induced charging damage in non-invasive optical way. In plasma dielectric via etching, the bombardment of reactive ions on exposed conductor patterns may induce electrical current. Induced electrical charge can further flow down to device level, and accumulated charges in the consecutive plasma processes during back-end metallization can create plasma induced charging damage to shift the threshold voltage of device. As a preliminary research for the hypothesis, we performed two phases experiment to measure the plasma induced current in etch environmental condition. We fabricated electrical test circuits to convert induced current to flickering frequency of LED output, and the flickering frequency was measured by high speed optical plasma monitoring system (OPMS) in 10 kHz. Current-frequency calibration was done in offline by applying stepwise current increase while LED flickering was measured. Once the performance of the test circuits was evaluated, a metal pad for collecting ion bombardment during plasma etch condition was placed inside etch chamber, and the LED output frequency was measured in real-time. It was successful to acquire high speed optical emission data acquisition in 10 kHz. Offline measurement with the test circuitry was satisfactory, and we are continuously investigating the potential of real-time in-situ plasma induce current measurement via OPMS.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2014년도 추계학술대회 논문집
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• pp.870-873
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• 2014

Green roof systems has widely been used on rooftop of buildings by considering environmental benefits in aspects of bio-diversity, storm-water runoff as well as noise reduction. To predict noise reduction effect by green roof systems, it is necessary to measure in-situ acoustical properties of the components by devices enabling in-situ measurements. In this study, Micro-flown, which is the state of the arts device to measure in-situ normalized impedance and absorption coefficient has been used to measure acoustical properties of green roof materials according to different water saturation condition in the materials.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 춘계학술대회 논문집 반도체 재료 센서 박막재료 전자세라믹스
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• pp.97-100
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• 2004

We have grown GaN layers with in-situ SiN mask by metal organic chemical vapor deposition (MOCVD) and study the characteristic of the GaN layer. We have changed the deposition time of SiN mask from 45s to 5min and obtain th optimum condition in 45s. The PL intensity of GaN with SiN mask improved 2 times to that without SiN mask and the carrier concentraion increased from $3.5{\times}10^{16}cm^{-3}$ to $1.8{\times}10^{17}cm^{-3}$. We have thus shown that the SiN mask improved significantly the optical properties of the GaN layer.

• 멤브레인
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• 제29권2호
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• pp.96-104
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• 2019

본 연구는 분리막 성능 저하로 기능을 상실한 역삼투막의 힐링을 통한 복원의 가능성을 알아보고자 하는 데에 목적이 있다. 손상된 막은 양이온고분자인 poly(styrene sulfonic acid) sodium salt (PSSA)와 음이온고분자인 polyethyleneimine(PEI)를 염석법을 이용하여 이중으로 코팅했으며 또한 소재의 순서를 바꿔 코팅을 수행했다. 그리고 농도, 시간, 이온세기 등에 따라 코팅된 역삼투막의 투과도와 배제율을 측정하여 손상된 막으로부터 복원된 정도를 알아보았다. 또한 역삼투 평막에서 복원이 우수한 조건을 가정용 정수기 모듈에 적용하여 손상된 역삼투막 모듈에 또한 대하여 복원 가능성을 알아보았다. 이로부터 PEI 30,000 ppm (IS = 0.1)/PSSA 20,000 ppm (IS = 0.7) 코팅 조건에서 역삼투막 모듈에 적용했을 때 염 배제율은 69%에서 86% (손상 전 모듈의 경우 90%)까지 복원되었다.

• 한국전기전자재료학회논문지
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• 제19권8호
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• pp.769-774
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• 2006

In this paper the ZnO thin films, which has used spotlight of next generation short wavelength LEDs and semiconductor laser were deposited based on RF magnetron sputtering is described. The temperature at substrate and work pressure, which has implemented in sputtering process of ZnO thin films were settle down at $100^{\circ}C$ and 15 mTorr respectively. The ZnO 5N has used target. The thickness of ZnO thin films was about $1.6{\mu}m$ which was measured by SEM analysis after the sputtering process. Structural properties of ZnO thin films by in-situ and atmosphere annealing were analyzed by XRD. Transformation of grain size and surface roughness were observed by AFM. XPS spectra showed that ZnO thin film had a peak positions corresponding to the $Zn_{2p}$ and the $O_{1s}$. As form above XPS, we confirmed that post-annealing condition changed the atom ratio of Zn/O and microstructure in ZnO thin films.

• Nuclear Engineering and Technology
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• 제55권1호
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• pp.190-200
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• 2023

As the field of application of in-situ gamma spectroscopy is diversified, proficiency is required for consistent and accurate analysis. In this study, a program was developed to virtually create gamma energy spectra of artificial nuclides, which are difficult to obtain through actual measurements, for training. The virtual spectrum was created by synthesizing the spectra of the background radiation obtained through actual measurement and the theoretical spectra of the artificial radionuclides obtained by a Monte Carlo simulation. Since the theoretical spectrum can only be obtained for a given geometrical structure, representative major geometries for in-situ measurement (ground surface, concrete wall, radioactive waste drum) and the detectors (HPGe, NaI(Tl), LaBr₃(Ce)) were predetermined. Generated virtual spectra were verified in terms of validity and harmonization by gamma spectrometry and energy calibration. As a result, it was confirmed that the energy calibration results including the peaks of the measured spectrum and the peaks of the theoretical spectrum showed differences of less than 1 keV from the actual energies, and that the calculated radioactivity showed a difference within 20% from the actual inputted radioactivity. The verified data were assembled into a database and a program that can generate a virtual spectrum of desired condition was developed.

• 한국환경과학회지
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• 제21권12호
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• pp.1455-1462
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• 2012

The vertical distributions of nitrifying bacteria in aerobic fixed biofilm were investigated to evaluate the relationship between nitrification performance and microbial community at different HRT. Fluorescent in situ hybridization (FISH) and portable ion selective microelectrode system were adopted to analyze microbial communities and ions profiles according to the biofilm depth. Cilia media packed MLE (Modified Ludzack-Ettinger) like reactor composed of anoxic, aerobic I/II was operated with synthetic wastewater having COD 200 mg/L and $NH_4{^+}$-N mg/L at HRT of 6 hrs and 4 hrs. Total biofilm thickness of aerobic I, II reactor at 4 hrs condition was over two times than that of 6 hrs condition due to the sufficient substrate supply at 4 hrs condition (6 hrs; aerobic I 380 ${\mu}m$ and II 400 ${\mu}m$, 4 hrs; aerobic I 830 ${\mu}m$ and II 1040 ${\mu}m$). As deepen the biofilm detection point, the ratio of ammonia oxidizing bacteria (AOB) was decreased while the ratio of nitrite oxidizing bacteria (NOB) was maintained similar distribution at both HRT condition. The ratio of AOB was higher at 4 hrs than 6 hrs condition and $NH_4{^+}$-N removal efficiency was also higher at 4 hrs with 89.2% than 65.4% of 6 hrs. However, the ratio of NOB was decreased when HRT was reduced from 6 hrs to 4 hrs and $NO_2{^-}$-N accumulation was observed at 4 hrs condition. Therefore, it is considered that insufficient HRT condition could supply sufficient substrate and enrichment of AOB in all depth of fixed biofilm but cause decrease of NOB and nitrite accumulation.

• 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.