• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2003년도 춘계학술대회 논문집 센서 박막재료 반도체 세라믹
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• pp.99-102
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• 2003

Tin dioxide thin films were deposited at $375^{\circ}C$ on alumina substrate by metal-organic chemical vapor deposition process to find the relationship between physicochemical properties and the annealing treatments. The small grains with heat treatments grew to the bunch of grains and then showed the hillocks on the film surface. The thickness decreased with annealing treatment. The measured binding energy (BE) and branching ratio of the Sn 3d spin-orbital doublet were typical of oxidized states of Sn and the BE of the O1s core level of about 530~530.65eV also confirmed the presence of O-Sn bonds. The BE of oxygen and tin with annealing treatment shifted to higher position. O/Sn atomic ratios of films deposited at $375^{\circ}C$ for 2min and 4min were 1.99 and 2.01, respectively. The value of the atomic ratio O/Sn of films deposited at $375^{\circ}C$ for 2min changed from 1.99 to 2.45 with annealing treatment. Gas sensitivity depended on annealing temperature, the sensitivity increased with increasing annealing temperature.

• 비파괴검사학회지
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• 제18권4호
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• pp.271-277
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• 1998

비파괴검사는 검사 자체와 검사 결과를 해석 또는 평가하는 것으로 크게 둘로 나눌 수 있다. 검사자체는 전자 기술 수준의 발전에 따라 많은 양을 단시간 내에 정밀하게 수행할 수 있으나 검사 결과 발견된 지시(indication)가 결함인지 혹은 이와 유사한 거짓 결함인지를 확인하기는 대단히 어려운 일이다 초음파 탐상의 경우 검사 결과 결함의 형상을 정확하게 인식하기 위해 컴퓨터를 활용한 다양한 첨단 신호 해석 기술이 개발되어 일부 활용되어오고 있는데 본 논문에서는 신호처리 기법의 하나인 집속 신호합성 기법(synthetic aperture focusing technique, SAFT)을 활용하여 탄소강에서의 결함 신호 해석을 시도하였으며 탄소강 평판내에 가공된 hole을 대상으로 수집된 초음파 신호를 이 기법을 적용하여 처리한 결과 결함으로부터의 신호대 잡음비에 있어서 많은 개선이 이루어진 것으로 판단된다.

• Journal of Radiation Protection and Research
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• 제36권2호
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• pp.64-70
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• 2011

국내 최초로 국내 원자력 관련 기관을 대상으로 내부피폭방사선량 상호비교 프로그램을 실시하여 국내 내부선량 평가결과의 조화성을 분석하였다. 이를 위하여 섭취경로, 흡수형태, 방사능 입자크기(AMAD) 및 섭취시점을 모르는 경우에 대한 내부선량 평가문제를 개발하였으며, 세 종류의 문제에 각 세 문항씩 총 9문항을 제시하였다. 이번 상호비교 프로그램에는 원자력의학원, 방사선보건연구원, 원자력발전소(고리, 영광, 울진)의 내부선량평가 담당자 7명이 참가하여 문제에 대한 답안을 제출하였으며, 각 문제별 참가자 답안의 기하평균에 대한 각 참가자 답안의 상대 비 분포는 $5.75{\times}10^{-4}$ ~ 9.81이었고, 평가과정에서 극히 일부의 답안을 제외할 경우 참가자 답안의 기하평균에 대한 각 참가자 답안의 상대 비는 0.216 ~ 3.12의 분포를 보였다.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 2003년도 학술대회지
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• pp.313-323
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• 2003

The sliding wear behaviors of Zircaloy-4 nuclear fuel rod were investigated using two support springs with convex and concave shapes in room temperature air and water. The main focus is to compare the wear behavior of various test variables such as slip amplitude, environment, contact contours with different spring shape and a number of cycles. The results indicated that wear volume and maximum wear depth increased with slip amplitude in both air and water, but their trends tended to change according to the spring shapes and test environments. In air condition, the wear volume was controlled by wear debris behavior generated on worn surface. As a result, final wear volume and maximum wear depth decreased if a ratio of protruded wear volume to worn area $(D_p)$ would be saturated to specific value. This is because wear particle layer could accommodate large strain by accumulating and transforming wear particle layer. However, in water condition, metal-to metal contact was more dominant and wear volume was greatly affected by changed mechanical behavior between contact surfaces since wear debris should be generated after repeated plastic deformation and fracture. After wear test, worn surfaces were examined using optical microscope and SEM and details of wear mechanism were discussed using a ratio of wear volume to worn area $(D_e)$ at each test condition.

• Bulletin of the Korean Chemical Society
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• 제34권2호
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• pp.519-523
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• 2013

When atomic layer deposition (ALD) is performed on a porous material by using an organometallic precursor, minimum exposure time of the precursor for complete coverage becomes much longer since the ALD is limited by Knudsen diffusion in the pores. In the previous report by Min et al. (Ref. 23), shrinking core model (SCM) was proposed to predict the minimum exposure time of diethylzinc for ZnO ALD on a porous cylindrical alumina monolith. According to the SCM, the minimum exposure time of the precursor is influenced by volumetric density of adsorption sites, effective diffusion coefficient, precursor concentration in gas phase and size of the porous monolith. Here we modify the SCM in order to consider undesirable adsorption of byproduct molecules. $TiO_2$ ALD was performed on the cylindrical alumina monolith by using titanium tetrachloride ($TiCl_4$) and water. We observed that the byproduct (i.e., HCl) of $TiO_2$ ALD can chemically adsorb on adsorption sites, unlike the behavior of the byproduct (i.e., ethane) of ZnO ALD. Consequently, the minimum exposure time of $TiCl_4$ (~16 min) was significantly much shorter than that (~71 min) of DEZ. The predicted minimum exposure time by the modified SCM well agrees with the observed time. In addition, the modified SCM gives an effective diffusion coefficient of $TiCl_4$ of ${\sim}1.78{\times}10^{-2}\;cm^2/s$ in the porous alumina monolith.

• 한국식품과학회지
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• 제7권4호
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• pp.212-220
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• 1975

국내에서 새로이 보급된 Indica형 장려품종인 통일미(統一米)와 Japonica형 재래장려품종인 진흥미(振興米)의 취반기호특성(炊飯嗜好特性)을 비교, 검토한 결과는 다음과 같다. 통일미는 진흥미와 비교할 때 취반시(炊飯時) 같은 가수율(加水率)에서 $4{\sim}6%$ 더 많은 수분을 흡수하였고 항상 높은 hardness를 나타내었으며 같은 hardness를 유지하기 위하여 20% 더 많은 가수율(加水率)을 요구하였다. texture특성치(特性値)중 hardness의 역수(逆數)로 부터 취반시(炊飯時) 최적가수율(最適加水率)을 구한 바 통일미는 140%, 진흥미는 120%이었다. 미반(米飯)의 호화도(糊化度)는 노화도(老化度)를 효소소화법( 酵素消化法), 요오드정색법(呈色法), texture측정법에 의하여 측정한 결과, 같은 가수율(加水率)에서 통일미는 진흥미보다 항상 낮은 호화도(糊化度)를 나타낸 반면 노화도(老化度)는 약간 떨어지는 경향이 있었다. 미분(米粉)의 amylogram 특성(特性)을 보면 통일미는 진흥미에 비하여 호화개시온도(糊化開始溫度)는 높은 반면 최고 점도(粘度)와 breakdown은 낮은 값을 나타내었다.

• 반도체디스플레이기술학회지
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• 제17권3호
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• pp.41-45
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• 2018

Two-dimensional (2D) materials have been studied extensively due to their excellent physical, chemical, and electrical properties. Among them, we report the material and device characteristics of tin disulfide ($SnS_2$). To apply $SnS_2$ as a channel layer in a transistor, $SnS_2$ channels were formed by a stripping method and a transfer method. The limitation of this method is that it is difficult to produce uniform device characteristics over a large area. Therefore, we directly deposited $SnS_2$ by atomic layer deposition (ALD) and then performed lithography. This method was able to produce devices with repeatable characteristics over a large area. However, the $SnS_2$ film was damaged by the acetone used as a photoresist (PR) developer during the lithography process, with the electrical properties of mobility of $2.6{\times}10^{-4}cm^2/Vs$, S.S. of 58.1 V/decade, and on/off current ratio of $1.8{\times}10^2$. These results are not suitable for advanced electronic devices. In this study, we analyzed the effect of acetone on $SnS_2$ and studied the device process to prevent such damage. Using polyvinyl alcohol (PVA) as a passivation layer during the lithography process, the electrical characteristics of the $SnS_2$ transistor had $2.11{\times}10^{-3}cm^2/Vs$ of mobility, 11.3 V/decade of S.S, and $2.5{\times}10^3$ of the on/off current ratio, which were 10x improvements to the $SnS_2$ transistor fabricated by the conventional method.

• Journal of Radiation Protection and Research
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• 제47권2호
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• pp.77-85
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• 2022

Background: After the Fukushima Daiichi Nuclear Power Station (FDNPS) accident, a model was developed to estimate the external exposure doses for residents who were expected to return to their homes after evacuation orders were lifted. However, the model's accuracy and uncertainties in parameters used to estimate external doses have not been evaluated. Materials and Methods: The model estimates effective doses based on the integrated ambient dose equivalent (H^*(10)) and life patterns, considering a dose reduction factor to estimate the indoor H^*(10) and a conversion factor from H^*(10) to the effective dose. Because personal dose equivalent (H_p(10)) has been reported to agree well with the effective dose after the FDNPS accident, this study validates the model's accuracy by comparing the estimated effective doses with H_p(10). The H_p(10) and life pattern data were collected for 36 adult participants who lived or worked near the FDNPS in 2019. Results and Discussion: The estimated effective doses correlated significantly with H_p(10); however, the estimated effective doses were lower than H_p(10) for indoor sites. A comparison with the measured indoor H^*(10) showed that the estimated indoor H^*(10) was not underestimated. However, the H_p(10) to H^*(10) ratio indoors, which corresponds to the practical conversion factor from H^*(10) to the effective dose, was significantly larger than the same ratio outdoors, meaning that the conversion factor of 0.6 is not appropriate for indoors due to the changes in irradiation geometry and gamma spectra. This could have led to a lower effective dose than H_p(10). Conclusion: The estimated effective doses correlated significantly with H_p(10), demonstrating the model's applicability for effective dose estimation. However, the lower value of the effective dose indoors could be because the conversion factor did not reflect the actual environment.

• 분석과학
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• 제17권5호
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• pp.416-422
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• 2004

시간분해 레이저 유도 파열 분광분석 (TRELIBS) 시스템을 구성하여 원자력발전소 계통재질의 성분을 정성 분석하는 데 응용하였다. 본 연구에서는 탄소강 (A106 Gr. B, A336 P11, A335 P22), 스텐인레스강 (type 304, type 316) 및 인코넬 계열 합금(인코넬 600, 인코넬 690, 인코넬 800) 시료를 사용하였다. 탄소강의 종류는 485~575 nm 파장영역에서 나타난 Cr/Fe과 Mo/Fe의 TRELIBS 피크 비에 의해서 서로 구분 가능하였다. type 304와 type 316 스텐인레스강은 485~575 nm 파장영역에서 나타나는 Mo의 TRELIBS 피크 존재 여부에 의해서 쉽게 구분 가능하였다: type 304는 어떤 Mo의 피크도 나타내지 않지만, type 316은 Mo의 피크를 보여준다. 인코넬 계열 합금강 종류는 420~510 nm 파장영역에서 나타난 Cr/Fe과 Ni/Fe의 TRELIBS 피크비에 의해서 서로 구분 가능하였다. TRELIBS는 시료의 전처리 없이 빠르고 쉽게 합금을 분석할 수 있는 효과적인 분석 기술임이 입증되었다.

• 비파괴검사학회지
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• 제20권4호
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• pp.314-321
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• 2000

모의 원자로내 용융물 냉각 실증 실험 결과 용융물 $Al_2O_3/Fe$ thermite 와 lower head vessel사이에 간극이 발생된다. 간극을 정량적으로 측정하기 위한 기존의 초음파 방법은 구조물의 복잡성과 $2300^{\circ}C$ 에서 용융되는 thermite $Al_2O_3/Fe,\;Al_2O_3$의 영향으로 발생되는 lower head의 열영향부위(HAZ)의 금속학적인 결정입자 크기의 변화로 결정 계면으로부터 발생되는 잡음신호와 초음파 산란, 감쇠, 모드 변환 등이 발생되어 신뢰성이 떨어지고 있다. 간극을 정량적으로 측정하기 위해서 thermite와 lower head 사이에 물이 채워진 형태의 즉 고체, 액체, 고체의 다층구조에서 초음파의 진행 및 반사 형태를 분류 및 분석하였다. 결정립의 잡음을 억제하기 위하여 주파수대역의 확률 처리 방식인 PT(polarity threshold) 알고리즘을 이용하여 약 6dB 신호 대 잡음비의 개선효과를 가져왔다.