• 한국수소및신에너지학회논문집
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• 제23권1호
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• pp.56-64
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• 2012

The ITER fuel cycle is designed for DT operation in equimolar ratio. It involves not only a group of fuelling system and torus cryo-pumping system of the exhaust gases through the divertor from the torus in tokamak plant, but also from the exhaust gas processing of the fusion effluent gas mixture connected to the hydrogen isotope separation in cryogenic distillation to the final safe storage & delivery of the hydrogen isotopes in tritium plant. Tritium plant system supplies deuterium and tritium from external sources and treats all tritiated fluids in ITER operation. Every operation and affairs is focused on the tritium inventory accountancy and the confinement. This paper describes the major fuel cycle processes and interfaces in the tritium plant in aspects of upcoming technologies for future hydrogen and/or hydrogen isotope utilization.

• 한국가스학회지
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• 제27권4호
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• pp.56-61
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• 2023

플랜트는 사회기반시설로써 중요한 보호시설이고, 여기서 발생 가능한 가스 누출 및 폭발과 같은 사고에 대한 안전성 확보는 설계 시 반드시 고려해야 한다. 하지만 플랜트에서의 폭발압력에 대한 연구는 경제성 등의 이유로 거의 없으며, 이에 대한 데이터가 부족한 실정이다. 본 연구에서는 플랜트에서 발생할 수 있는 폭발 시나리오를 고려한 실험 설계안을 제시하고 폭발 실험을 통해 폭압을 확인하였다. 가연성 물질로 수소-메테인 혼합 가스가 이용되었으며, 밀폐도와 밀집도가 폭압에 주는 영향에 대해 연구하였다. 밀폐도에 따라 압력파의 중첩이 폭압에 주는 영향과 밀집도에 따른 난류 영향을 구분하여 논의한다. 본 연구에서의 결과는 다양한 안전설계 시 입력자료로 활용될 수 있다.

• 한국산업보건학회지
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• 제24권1호
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• pp.46-51
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• 2014

Objectives: The principal aim of this study was to compare the concentrations of gaseous pollutants emitted in enclosed pig buildings between different rates of general ventilation and determine the variations in the patterns of gaseous pollutants as affected by ventilation rate. Materials and Methods: The experiment was performed in the growing/finishing room($20.0m{\times}12.0m{\times}3.0m$) of a pig confinement building located on the experimental farm of Seoul National University. The conditions of the general ventilation rate for three treatments were 30%($4.12m^3s^{-1}$), 50%($6.87m^3s^{-1}$) and 70%($9.61m^3s^{-1}$). The data presented in the study were collected overa total of 45 days, 15 days for each of the three treatments from March to May 2011. A total of six air samplings were taken at 1.5m above the floor of the pig building. The environmental agents measured in the pig building were ammonia, hydrogen sulfide and odor concentration index for gaseous pollutants with temperature and hydrogen sulfide for thermal factors. Results: There were significant differences in the ammonia and odor concentration index in the pig building among the three general ventilation rate conditions(p<0.05), whereas hydrogen sulfide did not show a significant difference among three conditions of general ventilation rate(p>0.05). As the general ventilation rate applied to the pig building increases, it appears that all the indoor environmental agents measured in this study simultaneously decrease. Conclusions: The gaseous pollutants significantly affected by the general ventilation rate in pig building were ammonia and odor concentration index(p<0.05). However, it was found that hydrogen sulfide and thermal factors, temperature and relative humidity were not influenced significantly by variation in the general ventilation rate.

• 한국재료학회지
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• 제28권2호
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• pp.124-128
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• 2018

N-type porous silicon (PS) layers and thermally oxidized PS layers have been characterized by various measuring techniques such as photoluminescence (PL), Raman spectroscopy, IR, HRSEM and transmittance measurements. The top surface of PS layer shows a stronger photoluminescence peak than its bottom part, and this is ascribed to the difference in number of fine silicon particles of 2~3 nm in diameter. Observed characteristics of PL spectra are explained in terms of microstructures in the n-type PS layers. Common features for both p-type and n-type PS layers are as follows: the parts which can emit visible photoluminescence are not amorphous, but crystalline, and such parts are composed of nanocrystallites of several nm's whose orientations are slightly different from Si substrate, and such fine silicon particles absorb much hydrogen atoms near the surfaces. Light emission is strongly dependent on such fine silicon particles. Photoluminescence is due to charge carrier confinement in such three dimensional structure (sponge-like structure). Characteristics of visible light emission from n-type PS can be explained in terms of modification of band structure accompanied by bandgap widening and localized levels in bandstructure. It is also shown that hydrogen and oxygen atoms existing on residual silicon parts play an important role on emission stability.

• Interaction and multiscale mechanics
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• 제4권3호
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• pp.207-217
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• 2011

International efforts have focused recently on the development of tungsten surfaces that can intercept energetic ionized and neutral atoms, and heat fluxes in the divertor region of magnetic fusion confinement devices. The combination of transient heating and local swelling due to implanted helium and hydrogen atoms has been experimentally shown to lead to severe surface and sub-surface damage. We present here a computational model to determine the relationship between the thermo-mechanical loading conditions, and the onset of damage and failure of tungsten surfaces. The model is based on thermo-elasticity, coupled with a grain boundary damage mode that includes contact cohesive elements for grain boundary sliding and fracture. This mechanics model is also coupled with a transient heat conduction model for temperature distributions following rapid thermal pulses. Results of the computational model are compared to experiments on tungsten bombarded with energetic helium and deuterium particle fluxes.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2003년도 춘계학술대회 논문집 디스플레이 광소자분야
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• pp.88-91
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• 2003

Si nanocrystallites thin films have been fabricated by pulsed laser deposition using a Nd:YAG laser. After deposition, samples were annealed at the temperature range of 400 to $800^{\circ}C$. Hydrogen passivation was then performed in the forming gas ($95%N_{2}+5%H_{2}$) at $500^{\circ}C$. Strong violet-indigo photoluminescence has been observed at room temperature on nitrogen ambient-annealed Si nanocrystallites. As a result of photoluminescence spectra and infrared absorption spectra, we conclude that the violet-indigo PL efficiency is related with oxygen vacancy in the $SiO_x$(x= 1.6-1.8) matrix.

• 분석과학
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• 제31권1호
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• pp.1-6
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• 2018

We used differential scanning calorimetry and a thermogravimetric analysis to investigate the effect of being confined in mesoporous MCM-41 on the decomposition of lithium borohydride and magnesium borohydride when heated. The confinement did not cause a phase transition of the metal borohydrides inside MCM-41, but did lower their decomposition temperature. With the exception of a lowering of the temperature, the decomposition reaction mechanism of the metal borohydrides was nearly the same for both the bulk and confined samples.

• Nuclear Engineering and Technology
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• 제20권4호
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• pp.246-252
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• 1988

KAERIT 토카막 장치의 플라즈마 생성을 위한 수소기차 방전실험에 관해 기술하였다. 이 실험에서는 일주전압, 토로이달 자장, 충전기체 압력, 오차자장 및 예비전리 등이 방전시작에 미치는 영향이 연구되었다. 오차자장은 방전에 가장 큰 영향을 미치는 인자로서 방전전압이 최소가 되는 것은 결국 오차자장 성분을 가장 잘 상쇄시켰을 때였다. 예비전리의 효과는 전반적으로 두드러지지는 않았지만 밀폐 성능이 나쁠수록 상대적으로 크게 나타났다. 실험적으로 구해진 방전시작조건은 이론적인 모델의 계산결과와 비교하였다. 실험에서의 방전영역이 이론적인 계산결과에 비해 줄어드는 경향을 보이고 있는 것은 고려되지 않은 다른 인자에 기인하는 것으로 판단되지만 토카막의 방전시작단계를 다루기에는 이 모델로도 충분하다.

• Journal of the Optical Society of Korea
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• 제9권3호
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• pp.123-128
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• 2005

An electrically controllable fiber Bragg grating inscribed in a hydrogen-loaded standard single-mode fiber with liquid-crystal cladding is presented. Control of the optic axis of liquid crystals by means of external electric fields results in the change of reflectivity and Bragg wavelength of the grating. The increase of surrounding refractive index of a fiber makes effective refractive index of a propagation mode higher, which results in high field confinement and longer Bragg wavelength. The reduction of the fiber diameter by chemical etching process improves the long-range ordering of liquid-crystal molecules and reduces controlling voltage. The tunable ranges of reflectivity and Bragg wavelength of the liquid crystal-cladding fiber Bragg grating were $\~4.6dB\;and\;\~0.3nm$, respectively.

• Nuclear Engineering and Technology
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• 제56권2호
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• pp.546-551
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• 2024

As an effective methods of plasma heating, neutral beam injection (NBI) systems based on negative hydrogen ion sources will be utilized in future magnetic-confinement nuclear fusion experiments. Because of the collisions between the fast negative ions and the neutral background gas, the positive ions are inevitable created in the acceleration region in the negative NBI system. These positive ions are accelerated back into the ion source and become high energy backstreaming ions. In order to explore the characters of backstreaming ions, the track and power deposition of backstreaming H⁺ beam is estimated using the experimental and simulation methods at NNBI test facility. Results show that the flux of backstreaming positive ions is 1.93 % of that of negative ion extraction from ion source, and the magnet filed in the beam source has an effect on the backstreaming positive ions propagation.