• Title/Summary/Keyword: Mo-Jeong

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A Study on the Fatigue Crack Growth Behavior of Cr-Mo- Steel for Pressure Vessel (압력용기용 Cr-Mo강의 균열진전거동에 관한 연구)

  • Choe, Byeong-Ik;Lee, Hak-Ju;Han, Seung-U;Kim, Chang-Uk;Cha, Jeong-Hwan;Kim, Jeong-Tae;Ji, Byeong-Ha
    • 연구논문집
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    • s.29
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    • pp.91-99
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    • 1999
  • Fatigue crack growth behaviors of Cr-Mo steels developed recently for thick-wall pressure vessel were investigated. Experiments in accordance with ASTM E647 standard were performed for 1/2 inch CT specimens of $2^(1/4)$Cr-1Mo and 3Cr-IMo steels in gaseous environments, hydrogen gas of 10 atm, 1 atm and argon gas of 1 atm. Fatigue crack growth rates were observed and effects of gaseous hydrogen and argon on the crack growth behavior were discussed.

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High-valence Mo doping for promoted water splitting of Ni layered double hydroxide microcrystals

  • Kyoungwon Cho;Seungwon Jeong;Je Hong Park;Si Beom Yu;Byeong Jun Kim;Jeong Ho Ryu
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.33 no.2
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    • pp.78-82
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    • 2023
  • The oxygen evolution reaction (OER) is the primary challenge in renewable energy storage technologies, specifically electrochemical water splitting for hydrogen generation. We report effects of Mo doping into Ni layered double hydroxide (Ni-LDH) microcrystal on electrocatalytic activities. In this study, Mo doped Ni-LDH were grown on three-dimensional porous nicekl foam (NF) by a facile solvothermal method. Homogeneous LDH structure on the NF was clearly observed. However, the surface microstructure of the nickel foam began to be irregular and collapsed when Mo precursor is doped. Electrocatalytic OER properties were analyzed by Linear sweep voltammetry (LSV) and Electrochemical impedance spectroscopy (EIS). The amount of Mo doping used in the electrocatalytic reaction was found to play a crucial role in improving catalytic activity. The optimum Mo amount introduced into the Ni LDH was discussed with respect to their OER performance.

Syntheses and mechanical properties of Cr-Mo-Si-N coatings by a hybrid coating system (하이브리드 공정을 이용한 Cr-Mo-Si-N 코팅의 합성 및 기계적 성질)

  • Lee, Jeong-Du;Kim, Gwang-Ho
    • Proceedings of the Korean Institute of Surface Engineering Conference
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    • 2008.11a
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    • pp.86-87
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    • 2008
  • 4성분계 Cr-MO-Si-N코팅은 하이브리드 시스템에 아르곤, 질소 가스를 주입하여 스테인리스 기판과 실리콘 웨이퍼에 증착시킨다. XRD, XPS, HRTEM을 이용해 Cr-MO-Si-N코팅의 성분을 분석하고 Si의 함량이 12.1at.%일때 50GPa의 강도가 나오고 이것은 33GPa의 강도Cr-MO-N코팅보다 크게 향상된 것이다.

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Preparation of Screen Printable Conductive MoSi2 Thick Films for Ceramic Sheet Heater (Screen Printable MoSi2 도전성 Paste를 이용한 세라믹 면상 발열체 제조)

  • Kim, Bae-Yeon;Han, Dong-Bin;Jeong, Cheol-Weon
    • Journal of the Korean Ceramic Society
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    • v.47 no.4
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    • pp.319-324
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    • 2010
  • Screen printable $MoSi_2$ paste and its ceramic sheet heater were investigated. $MoSi_2$ powder without $Mo_5Si_3$ second phase, which causes so-called pest phenomena, was synthesized by SHS technique. Over glaze was also developed for preventing pest phenomenon. The maximum temperature of $MoSi_2$ ceramic heater was over $500^{\circ}C$. After several heat up and cooling cycle, the $MoSi_2$ heater reveals pest phenomenon. Conductive $MoSi_2$ paste could be used in electronic ceramics, i.e., MLCC, LTCC, HTCC, and etc.

The Charge-Discharge Performance of $Li/MoS_2$ Battery with liquid Electrolyte of Tetra(ethylene glycol] Dimethyl Ether[TEGDME] (TEGDME 액체 전해질을 사용한 $Li/MoS_2$ 전지의 충.방전 특성)

  • Kwon, Jeong-Hui;Ryu, Ho-Suk;Kim, Ki-Won;Ahn, Jou-Hyeon;Jeong, Yong-Su;Lee, Kun-Hwan;Ahn, Hyo-Jun
    • Transactions of the Korean hydrogen and new energy society
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    • v.20 no.3
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    • pp.238-244
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    • 2009
  • We investigated the electrochemical properties of lithium/molybdenum sulfide(Li/MoS$_2$) using tetra (ethylene glycol) dimethyl ether(TEGDME) electrolyte. The Li/TEGDME/MoS$_2$ cell showed the first discharge capacity of 288mAhg$^{-1}$. From the XRD, SEM results of the MOS$_2$ electrode in various cut-off voltage during charge-discharge process, MoS$_2$ partly changed into Li$_2$S and Mo during discharge and Li$_2$S partly recovered into MOS$_2$ and Li during charge. Full charged MOS$_2$ electrode showed lump shape of big size, which might be related to agglomerate of MoS$_2$ particles. Therefore, the degradation might be related to decrease of active material for electrochemical reaction by agglomeration of MOS$_2$.

Heterojunction Solar Cell with Carrier Selective Contact Using MoOx Deposited by Atomic Layer Deposition (원자층 증착법으로 증착된 MoOx를 적용한 전하 선택 접합의 이종 접합 태양전지)

  • Jeong, Min Ji;Jo, Young Joon;Lee, Sun Hwa;Lee, Joon Shin;Im, Kyung Jin;Seo, Jeong Ho;Chang, Hyo Sik
    • Korean Journal of Materials Research
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    • v.29 no.5
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    • pp.322-327
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    • 2019
  • Hole carrier selective MoOx film is obtained by atomic layer deposition(ALD) using molybdenum hexacarbonyl[$Mo(CO)_6$] as precursor and ozone($O_3$) oxidant. The growth rate is about 0.036 nm/cycle at 200 g/Nm of ozone concentration and the thickness of interfacial oxide is about 2 nm. The measured band gap and work function of the MoOx film grown by ALD are 3.25 eV and 8 eV, respectively. X-ray photoelectron spectroscopy(XPS) result shows that the $Mo^{6+}$ state is dominant in the MoOx thin film. In the case of ALD-MoOx grown on Si wafer, the ozone concentration does not affect the passivation performance in the as-deposited state. But, the implied open-circuit voltage increases from $576^{\circ}C$ to $620^{\circ}C$ at 250 g/Nm after post-deposition annealing at $350^{\circ}C$ in a forming gas ambient. Instead of using a p-type amorphous silicon layer, high work function MoOx films as hole selective contact are applied for heterojunction silicon solar cells and the best efficiency yet recorded (21 %) is obtained.

A study on the mechanically equivalent surrogate plate of U-Mo dispersion fuel using tungsten

  • Kim, Hyun-Jung;Yim, Jeong-Sik;Jeong, Yong-Jin;Lee, Kang-Hee
    • Nuclear Engineering and Technology
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    • v.51 no.2
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    • pp.495-500
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    • 2019
  • When a new fuel is developed, various mechanical properties are absolutely necessary for a safety analysis of the fuel for the licensing and prediction of its mechanical behavior during operation and accident conditions. In this paper, a mechanically equivalent surrogate plate of U-Mo dispersion fuel is presented using tungsten, substitute material of U-Mo particle. A surrogate plate, composed of tungsten/aluminum dispersion meat and aluminum alloy cladding, is manufactured with the same fabrication process with that of fuel plate except that a tungsten powder is used instead of U-Mo powder. A modal test showed that the surrogate plate and fuel plate have similar dynamic characteristics, and a tensile test demonstrated the similarity of the material property up to the yield strength range. The conducted tests proved that the surrogate tungsten plate has equivalent mechanical behaviors with that of a fuel plate, which leads to the acceptable use of a surrogate fuel assembly using tungsten/aluminum dispersion meat in various mechanical tests. The surrogate fuel assembly can be utilized for various out-of-pile characteristic tests, which are necessary for the licensing achievement of a research reactor that uses U-Mo dispersion fuel as a driver.

Investigation of Physicochemical Properties of Mo Carbide Utilizing Electron Spectroscopy

  • Jeong, Eunkang;Park, Juyun;Kang, Yong-Cheol
    • Journal of Integrative Natural Science
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    • v.13 no.3
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    • pp.87-91
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    • 2020
  • Molybdenum carbide (MoCx) thin films (TFs) were deposited by reactive radio frequency (rf) magnetron co-sputtering in high vacuum chamber. We compared the properties of MoCx thin films as the rf power changed on C target. The result of alpha step measurement showed that the thickness of the MoCx TFs varied from163.3 to 194.86 nm as C power was increased from 160 to 200 W. The crystallinity of MoCx such as b-Mo2C, Mo2C, and diamond like carbon (DLC) structures were observed by XRD. The oxidation states of Mo and C were determined using high resolution XPS spectra of Mo 3d and C 1s were deconvoluted. Molybdenum was consisted of Mo, Mo4+, and Mo6+ species. And C was deconvoluted to C-Mo, C, C-O, and C=O species.