• 전자공학회논문지A
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• 제30A권11호
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• pp.122-131
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• 1993

In this paper, we have developed a submicron Si MOSFET simulator, which is physically based on the hydrodynamic energy transport mode. The simulator was used to investigate the nonstationary transport effects and the transient phenomena in submicron Si MOSFET's. It is found that the velocity overshoot and the carrier heating are dominant transport mechanism near the drain end of the channel and the transient phenomena is more retained in a long channel MOSFET.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2005년도 제17회 워크샵 및 추계학술대회
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• pp.567-567
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• 2005

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 2001년도 추계학술발표회요약집
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• pp.56-56
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• 2001

• 한국방사성폐기물학회:학술대회논문집
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• 한국방사성폐기물학회 2019년도 춘계학술논문요약집
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• pp.110-111
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• 2019

• 대한기계학회논문집A
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• 제22권4호
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• pp.826-833
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• 1998

The energy-absorbing characteristic of impact limiters affects the cask design so significantly that it should be evaluated as accurate as possible. The objective of this study is to find the influence of the impact limiter's steel case and gusset plates which enclose the shock absorbing cellular material on the impact energy absorption. The influence of impact limiter's steel case and gusset plate stiffeners on the impact energy absorption behavior under horizontal drop impact was evaluated for a radioactive isotope transport cask. Though the impact limiters mitigate the impact damage of the cask, the impact limiter's steel case and gusset plate stiffeners increase the impact force so significantly that should be designed as soft as possible. The impact analysis without considering impact limiter's steel case and gusset plates stiffener gives non-conservative results, so the stiffness of the steel case and gusset plates should be considered in impact analysis.

• 한국대기환경학회지
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• 제28권4호
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• pp.466-476
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• 2012

This study calculated monthly and sectoral (for industry, energy industry, transport, residential, commercial and public sectors) greenhouse gas (GHG) emissions of Seoul, Korea from 1999 until 2009 with following the IPCC 2006 Guideline for National Greenhouse Gas Inventories through an analysis on available monthly data of fossil fuel and electricity consumption for the period. The time series analysis showed that GHG emissions had significant cyclical pattern season by season with the highest peak in August and the lowest peak in January throughout the period. The analysis on monthly and sectoral energy consumption showed that residential, commercial and public sectors had emitted about 65% of total GHG emissions of Seoul and had consumed more energy in winter for heating. About 30% GHG of Seoul was emitted from transport sector but its monthly energy consumption showed irregular pattern and it consumed 80% petroleum (in 2009) of Seoul. Hopefully together with further study on this subject, it is expected that this study can be used as basic data for various research regarding Greenhouse gas baseline emission, energy consumption pattern and estimation for future GHG emission of Seoul.

• 전기학회논문지P
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• 제64권4호
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• pp.241-245
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• 2015

Energy Distribution Function in pure $CH_4$, $CF_4$ and mixtures of $CF_4$ and Ar, have been analyzed over a range of the reduced electric field strength between 0.1 and 350[Td] by the two-term approximation of the Boltzmann equation (BEq.) method and the Monte Carlo simulation (MCS). The calculations of electron swarm parameters require the knowledge of several collision cross-sections of electron beam. Thus, published momentum transfer, ionization, vibration, attachment, electronic excitation, and dissociation cross-sections of electrons for $CH_4$, $CF_4$ and Ar, were used. The differences of the transport coefficients of electrons in $CH_4$, mixtures of $CH_4$ and Ar, have been explained by the deduced energy distribution functions for electrons and the complete collision cross-sections for electrons. The results of the Boltzmann equation and the Monte Carlo simulation have been compared with the data presented by several workers. The deduced transport coefficients for electrons agree reasonably well with the experimental and simulation data obtained by Nakamura and Hayashi. The energy distribution function of electrons in $CF_4$-Ar mixtures shows the Maxwellian distribution for energy. That is, $f({\varepsilon})$ has the symmetrical shape whose axis of symmetry is a most probably energy.

• Journal of Radiation Protection and Research
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• 제26권3호
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• pp.225-229
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• 2001

In Korea, an advanced reactor system of 330MWt power called SMART (System integrated Modular Advanced ReacTor) is being developed by KAERI to supply energy for seawater desalination as well as electricity generation. A shielding design of the SMART core with 49 CEDM is established by a two-dimensional discrete ordinates radiation transport analyses. The DORT two-dimensional discrete ordinates transport code is used to evaluate the SMART shielding designs. Three axial regions represent the SMART reactor assembly, each of which is modeled in the R-Z geometry. The BUGLE-96 library is used in the analyses, which consists of 47 neutron and 20 gamma energy groups. The results indicate that the maximum neutron fluence at the bottom of reactor vessel is $5.89 {\times} 10^{17}\;n/cm^2$ and that on the radial surface of reactor vessel is $4.49 {\times} 10^[16}\;n/cm^2$. These results meet the requirement, $1.0 {\times} 10^{20}\;n/cm^2$, in 10 CFR 50.61 and the integrity of SMART reactor vessel during the lifetime of the reactor is confirmed.

• 한국ITS학회 논문지
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• 제11권2호
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• pp.83-91
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• 2012

TV 대역 White Space 송수신기에서 스펙트럼 센싱을 위한 RF 에너지 검출기 구조를 제안하였다. 제안된 에너지 검출기는 RF 능동 필터 구조에 기반하며, RF 저잡음 증폭기에 고역통과필터를 포함하는 피드포워드 루프를 추가함으로써 원하는 RF 주파수 성분만 통과시키고 그 외의 대역은 감쇄시키는 동작을 수행한다. 본 연구에서는 기존의 구조가 갖는 단점인 단측파 대역만 억압할 수 있는 문제를 해결하고자 양측파 대역을 동시에 억압할 수 있는 새로운 구조를 제안하였고, 간단한 시스템 모델링을 통해 구성요소의 Non-ideality에 의한 RF 에너지 검출기 성능에 대한 영향을 평가하였다. 또한, 시스템 시뮬레이션을 통해 양측파대역이 효과적으로 감쇄되어 RF 에너지 검출기로서 동작할 수 있음을 보였다.

• 자원환경지질
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• 제41권6호
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• pp.719-729
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• 2008

본 연구에서는 지구화학 모델을 활용하여 지하수 환경에서의 우라늄의 존재 형태, 흡착 및 이동 특성을 모사해 보았다. 흡착에 의한 우라늄의 지연 이동을 효과적으로 모사하기 위하여 3차원 지하수 유동 모델과 반응성 용질 이동 모델을 활용하였다. 모사 결과, $pCO_2=10^{-3.6}$조건에서 대부분의 우라늄 흡착(최대 99.5%)은 pH 5.5와 띠에서 발생하였다. $pCO_2$가 $10^{-2.5}$인 경우 우라늄이 대부분 흡착되는 pH범위는 6에서 7사이로 매우 좁았으며, 반면 $pCO_2=10^{-4.5}$인 경우에는 흡착되는 pH가 범위가 상대적으로 넓어 pH 5.5에서 8.5사이에서 대부분 흡착되었다. 음이온 화합물을 고려한 경우에는 pH 6 이하에서는 불소착물의 형성에 의해 우라늄 흡착이 감소하였다. 본 연구를 통하여, 우라늄 이동이 pH, $pCO_2$ 및 음이온의 종류와 농도 등 지하수의 지화학적 조건에 의해 상당히 영향을 받음을 알 수 있었다. 향후 여러 부지 조사 및 평가와 관련하여 우라늄 및 기타 유해성 화합물의 환경 영향을 예측하는데 있어 지구화학 모델이 중요한 도구로 활용되어야 할 것이다.