• Title/Summary/Keyword: Energy Deposition

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Effect of Agricultural Countermeasures on Ingestion Dose Following a Nuclear Accident

  • Keum, Dong-Kwon;Jeong, Hyojoon;Jun, In;Lim, Kwang-Muk;Choi, Yong-Ho;Lee, So-Hyeon;Jung, Tae-Jong
    • Journal of Radiation Protection and Research
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    • v.44 no.1
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    • pp.8-14
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    • 2019
  • Background: Management of an agricultural food product system following a nuclear accident is indispensable for reducing radiation exposure due to ingestion of contaminated food. The present study analyzes the effect of agricultural countermeasures on ingestion dose following a nuclear accident. Materials and Methods: Agricultural countermeasures suitable for domestic farming environments were selected by referring to the countermeasures applied after the Fukushima accident in Japan. The avertable ingestion doses that could be obtained by implementing the selected countermeasures were calculated using the Korean Agricultural Countermeasure Analysis Program (K-ACAP) to investigate the efficiency of each countermeasure. Results and Discussion: Of the selected countermeasures, the management of crops was effective when radionuclide deposition occurred during the growing season of plants. Treatment by soil additive and topsoil removal was effective when deposition occurred during the nongrowing season of plants. The disposal of milk was not effective owing to the small contribution of milk to the overall ingestion dose. Clean feeding of livestock was effective when deposition occurred during the growing season of fodder plants such as pasture and rice-straw. Finally, the effect of food restriction increased with the soil deposition density of radionuclide. The practical effect of countermeasures was very small when the avertable ingestion dose was absolutely low. Conclusion: The agricultural countermeasures selected to reduce the radionuclide ingestion dose after a nuclear accident must be made appropriate by considering the accident situation, such as the soil deposition density of the radionuclide and the deposition date in relation to farming cycles.

The Electrical Characteristics of Chromium Oxide Film Produced by Son Beam Sputter Deposition (이온선 스퍼터 증착법에 의하여 제조된 CrOx의 전기적 특성)

  • 조남제;이규용
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.15 no.6
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    • pp.518-523
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    • 2002
  • The influences of ion beam energy and reactive oxygen partial pressure on the physical and crystallographic characteristics of transition metal oxide compound(CrOx) film were studied in this paper. Chromium oxide films were deposited onto a cover-glass using ion Beam Sputter Deposition(IBSD) technique according to the various processing parameters. Crystallinity and grain size of as-deposited films were analyzed using XRD analysis. Thickness and Resistivity of the films were measured by $\alpha$-step and 4-point probe measurement. According to the XRD, XPS and resistivity results, the deposited films were the cermet type films which had crystal structure including amorphous oxide(a-oxide) phase and metal Cr phase simultaneously. The increment of the ion beam energy during the deposition process led to decreasing of metal Cr grain size and the rapid change of resistivity above the critical $O_2$ partial pressure.

Fabrication of NiO buffer film on textured Ni substrate for YBCO coated conductor (Textured Ni 기판 위에 YBCO coated conductor 모재용 NiO 완충층 제조)

  • Sun, Jong-Won;Kim, Hyoung-Seop;Jung, Choon-Ghwan;Lee, Hee-Gyoun
    • Progress in Superconductivity
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    • v.3 no.1
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    • pp.125-129
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    • 2001
  • NiO buffer layers were deposited on texture Ni tapes fur YBCO coated conductors by MOCVD(metal organic chemical vapor deposition) method, using a single solution source. Variables were deposition temperature and flow rate of $0_2$carrier gas. At higher temperatures, The NiO(111) texture was well developed, but the NiO(200) texture was developed at low temperatures. The best result was obtained at the deposition temperature of$ 470^{\circ}C$ and the gas flow rate of 200 sccm. FWHM value of $\omega$-scan fur NiO(200) of the film and $\Phi$-scan for NiO(111) of the film was $4.2^{\circ}$ and $7^{\circ}$, respectively.

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Crystallization behavior of ITO thin films sputtered on substrates with and without heating (가열기판 및 비가열 기판에 증착한 ITO 박막의 결정화 거동)

  • Park, Ju-O;Lee, Joon-Hyung;Kim, Jeong-Joo;Cho, Sang-Hee
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2003.08a
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    • pp.89-92
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    • 2003
  • ITO thin films were deposited by RF-magnetron sputtering method and crystallization behavior of the films with and without external heating as a function of deposition time was examined. X-ray diffraction results indicated an amorphous state of the film when the deposition time is short about 10 min. When the deposition time was increased over 20 min development of crystallization of the films is observed. Because RF-sputtering transfers the high-energy to the growing film by energetic bombardment, it is believed that considerable activation energy for the crystallization of the film has transferred during deposition, which resulted in the crystallization of ITO thin films without external energy supply.

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A Review on Ultrathin Ceramic-Coated Separators for Lithium Secondary Batteries using Deposition Processes (증착 기법을 이용한 리튬이차전지용 초박막 세라믹 코팅 분리막 기술)

  • Kim, Ucheol;Roh, Youngjoon;Choi, Seungyeop;Dzakpasu, Cyril Bubu;Lee, Yong Min
    • Journal of the Korean Electrochemical Society
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    • v.25 no.4
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    • pp.134-153
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    • 2022
  • Regardless of a trade-off relationship between energy density and safety, it is essential to improve both properties for future lithium secondary batteries. Especially, to improve the energy density of batteries further, not only thickness but also weight of separators including ceramic coating layers should be reduced continuously apart from the development of high-capacity electrode active materials. For this purpose, an attempt to replace conventional slurry coating methods with a deposition one has attracted much attention for securing comparable thermal stability while minimizing the thickness and weight of ceramic coating layer in the separator. This review introduces state-of-the-art technology on ceramic-coated separators (CCSs) manufactured by the deposition method. There are three representative processes to form a ceramic coating layer as follows: chemical vapor deposition (CVD), atomic layer deposition (ALD), and physical vapor deposition (PVD). Herein, we summarized the principle and advantages/disadvantages of each deposition method. Furthermore, each CCS was analyzed and compared in terms of its mechanical and thermal properties, air permeability, ionic conductivity, and electrochemical performance.

Studies on the Properties of the Plasma TEOS $SiO_2$ Film (PECVD TEOS $SiO_2$막의 특성에 관한 연구)

  • 이수천;이종무
    • Journal of the Korean Ceramic Society
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    • v.31 no.2
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    • pp.206-212
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    • 1994
  • Effects of the film deposition process parameters on the properties such as deposition rate, etch rate, refractive index, stress and step coverage of plasma enhanced chemical vapor deposited (PECVD) tetraethylorthosilicate glass (TEOS) SiO2 film were investigated and analysed using SEM, FTIR and SIMS techniques. Increasing TEOS flow or decreasing O2 flow increased the deposition rate and the compressive stress of the oxide film but produced a less denser film. The deposition rate decreased owing to the decrease in the sticking coefficient of the TEOS and the O2 molecules onto the substrate Si with increasing the substrate temperature. Increasing the substrate temperature produced a denser film with a lower etch rate and the higher refractive index by lowering SiOH and moisture contents. Increasing the rf power increases the ion bombardment energy. This increase in energy, in turn, increases the deposition rate and tends to make the film denser. No appreciable changes were found in the deposition rate but the refractive index and the stress of the film decreased with increasing the deposition pressure. The carbon content in the plasma TEOS CVD oxide film prepared under our standard deposition conditions were very low according to the SIMS analysis results.

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Atomistic Study of Metal Cluster Deposition and Nanowires (금속 덩어리 증착 및 금속 나노와이어에 관한 원자단위 이론 연구)

  • 강정원;이강환;황호정
    • Proceedings of the IEEK Conference
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    • 2001.06b
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    • pp.21-24
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    • 2001
  • We studied aluminum cluster deposition using molecular dynamics simulation. We investigated the variations of the cluster momentum and the impulse force during collisions, and found that the close-packed cluster impact has some of properties of the single particle collision and the linear chain collisions. We also simulated the series of energetic cluster deposition with energy Per atom. When energy Per atom in cluster has some eV rather than very low, the intermixing occurred easily in growth film and we can obtain a good film without subsequent annealing process.

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Steam Reforming of Toluene Over Ni/Coal Ash Catalysts: Effect of Coal Ash Composition

  • Jang, Jinyoung;Oh, Gunung;Ra, Ho Won;Yoon, Sung Min;Mun, Tae Young;Seo, Myung Won;Moon, Jihong;Lee, Jae-Goo;Yoon, Sang Jun
    • Korean Chemical Engineering Research
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    • v.59 no.2
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    • pp.232-238
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    • 2021
  • The development of a low cost catalyst with high performance and small amount of carbon deposition on catalyst from toluene steam reforming were investigated by using coal ash as a support material. Ni-loaded coal ash catalyst showed similar catalytic activity for toluene steam reforming compared with the Ni/Al2O3. At 800 ℃, the toluene conversion was 77% for Ni/TAL, 68% for Ni/KPU and 78% for Ni/Al2O3. Ni/TAL showed similar toluene conversion to Ni/Al2O3. However, Ni/KPU produced higher hydrogen yield at relatively lower toluene conversion. Ni/KPU catalyst showed a remarkable ability of suppressing the carbon deposition. The difference in coke deposition and hydrogen yield is due to the composition of KPU ash (Ca and Fe) which increase coke resistance and water gas shift reaction. This study suggests that coal ash catalysts have great potential for the application in the steam reforming of biomass tar.

An Experimental Study on the Direct Contamination Pathway of Elemental iodine Vapor $(I_2)$ for Rice Plants (벼에 대한 원소상 요오드 증기$(I_2)$의 직접오염경로 해석 실험)

  • Choi, Y.H.;Lim, K.M.;Lee, C.M.;Park, H.G.;Park, D.W.;Choi, G.S.;Choi, H.J.;Lee, H.S.;Lee, C.W.
    • Journal of Radiation Protection and Research
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    • v.29 no.3
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    • pp.165-172
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    • 2004
  • Rice plants were exposed to $I_2$ vapor for 80 min at different growth stages in an exposure box to investigate the parameters concerning direct plant contamination. Deposition velocity $(m\;s^{-1})$ of the $I_2$ vapor for the straws was in the range of $1.4{\times}10^{-5}-1.3{\times}10^{-4}$ depending on the exposure time, being comparatively low during the earlier part of the plant growth. Ear deposition velocity was in the range of $2.5{\times}10^{-5}-6.7{\times}10^{-5}$. Whole-plant deposition velocity was in the range of $1.4{\times}10^{-5}-1.8{\times}10^{-4}$ with the highest from the exposure performed on Aug. 18 (7 d after the start of heading). The time-dependent variation generally decreased when the deposition velocity was normalized to the biomass density No noteworthy tendency in the deposition velocity was observed with regard to the temperature, sunlight and humidity. Translocation factor for the hulled seeds was $3.3{\times}10^{-5}-4.7{\times}10^{-4}$ with the highest from the Aug. 23 exposure. It was found that a leaf deposition even before the ear emergence resulted in a considerable seed translocation.