• Title/Summary/Keyword: molybdenum(Mo)

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The Correlation Properties between Substrate and Molybdenum Back Contacts Fabricated by DC Magnetron Sputtering (DC 반응성 스퍼터링법에 의해 제조된 몰리브덴 후면전극과 기판과의 상관특성분석)

  • Kim, Seok-Gi;Han, Sang-Ok
    • The Transactions of the Korean Institute of Electrical Engineers C
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    • v.49 no.3
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    • pp.149-154
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    • 2000
  • Bi-layer Mo films were deposited on soda-lime glass substrates using DC magnetron supttering. Increasing gas pressure, the resistivity varied from $1\times10^{-5}\; to\; 8.3\times10^{-3}\; \Omega.cm$. Furthermore, stress direction yielded compressive-to-tensile transition stress curves. The micro-structure of the compressively-stressed film which had poor adhesion consists of tightly packed columns, but of the tensile-stressed films had less dense structure. Under all gas pressure conditions, Mo films exhibited distinctly increasing optical reflection with decreasing gas pressure. The expansion of (110) peak width with the gas pressure meant the worse crystalline growth. The impurity levels in the Mo film exhibited highly concentrated Na, Se and O elements due to less dense micro-structure. The degree of Na diffusion depends on the type of the glass substrate used and the nature of the Mo film.

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A Study on the Trace Metal Contents in Food by Neutron Activation Analysis (방사화 분석법에 의한 식품 중 미량금속(Mg, Zn, Mn, Mo and Se)에 관한 연구)

  • 이숙경
    • Journal of Food Hygiene and Safety
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    • v.12 no.4
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    • pp.328-332
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    • 1997
  • In order to investigate the trace metals in Korean foods, the contents of Magnesium, Zinc, Manganese, Molybdenum and Selenium are studied in this paper. As show in the Table 1; a total of 250 samples of 25 species were analyzed by neutron activation analysis. The results obtained were as follows; 1. The overall ranges and mean (mg/100 g) were; Mg, 12.212∼151.346(55.164); Zn, 0.045∼38.180 (2.473); Mn, 0.003∼0.796 (0.225);Mo, ND∼0.035 (0.007); Se, ND∼0.069 (0.016). 2. The levels of all metals except Mo in shell fishes were high and the level of Mo in spices was higher than that in other foods. 3. The levels of Zn and Mo in oyster were higher than another spcies.

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Oxidation Behavior of $SiC/MoSi_2$ Composites Prepared by Reaction Sintering Method (반응소결에 의하여 제조된 $SiC/MoSi_2$ 복합체의 산화 거동)

  • 양준환;한인섭;우상국;서동수
    • Journal of the Korean Ceramic Society
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    • v.31 no.12
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    • pp.1588-1598
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    • 1994
  • The SiC/MoSi2 composite materials were fabricated by infiltrating the mixture of molybdenum disilicide and metal silicon(MoSi2+Si=100) to a porous compact of silicon carbide and graphite under the vacuum atmosphere of 10-1 torr. The specimen were oxidized in dry air under 1 atm at 130$0^{\circ}C$~150$0^{\circ}C$ for 240 hours. The oxidation behavior was evaluated by the weight gain and loss per unit area of the oxidized samples. Also, SEM and XRD analysis of the oxidized surface of the samples were carried out. With increasing the MoSi2 content and oxidation temperature, the passive oxidation was found. The trend of weight gain of all samples was followed the parabolic rate law with the formation of a protective layer of cristobalite on the surface.

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The study of crystallization to Si films deposited using a sputtering method on a Mo substrate (Mo기판 위에 sputtering 법으로 성장된 Si 박막의 결정화 연구)

  • 김도영;고재경;박중현;이준신
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2002.07a
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    • pp.36-39
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    • 2002
  • Polycrystalline silicon (poly-Si) thin film transistor (TFT) technology is emerging as a key technology for active matrix liquid crystal displays (AMLCD), allowing the integration of both active matrix and driving circuit on the same substrate (normally glass). As high temperature process is not used for glass substrate because of the low softening points below 450$^{\circ}C$. However, high temperature process is required for getting high crystallization volume fraction (i.e. crystallinity). A poly-Si thin film transistor has been fabricated to investigate the effect of high temperature process on the molybdenum (Mo) substrate. Improve of the crystallinity over 75% has been noticed. The properties of structural and electrical at high temperature poly-Si thin film transistor on Mo substrate have been also analyzed using a sputtering method

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A Computational Study for Designing Electrical Contacts to MoS2 Monolayers

  • Kim, Hwi-Su;Ha, Hyeon-U
    • Proceeding of EDISON Challenge
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    • 2014.03a
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    • pp.478-482
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    • 2014
  • Graphene have renewed considerable interest in inorganic, two-dimensional materials for future electronics. However, graphene does not have a bandgap, it is limited to apply directly to transistors and logic devices. Hence, other layered materials such as molybdenum disulphide ($MoS_2$) have been investigated to address this challenge. Here, we find that the nature of contacts plays a more important role than the semiconductor itself. In order to understand the nature of $MoS_2$/metal contacts, we perform density functional theory electronic structure calculations based on linear combination of atomic for the geometry, bonding, binding energy, PDOS, LDOS and electronic structure. We choose Au as a contact metal because it is the most common contact metal. In this paper, we demonstrate $MoS_2$/Au contacts have a more promising potential in flexible nanoelectronics than $MoS_2$ itself.

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Neutron Diffraction Analysis of Tungsten-Molybdenum-Disilicide Powders Formed by Self-propagating High Temperature Synthesis

  • Choi, Y.;Kim, Y.S.
    • Proceedings of the Korean Powder Metallurgy Institute Conference
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    • 2006.09b
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    • pp.1325-1326
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    • 2006
  • Tungsten-molydiside $W_xMo_{1-x}Si_2$ was synthesized by self-propagating high temperature synthesis (SHS). The SHS product with the initial composition of (0.5Mo+0.5W+2Si) contains 23.9% $MoSi_2$, 40.89% $WSi_2$ with remaining 9.11% Mo, 9.16% Si and 16.94%W. Lattice parameters of the $MoSi_2$ and $WSi_2$ determined by Rietvelt analysis were a=0.3206 nm, c=0.7841 nm and a=0.3212 nm, c=0.7822 nm, respectively.

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Effect of Sinter/HIP Technology on Properties of TiC-NiMo Cermets

  • Kollo, Lauri;Pirso, Juri;Juhani, Kristjan
    • Proceedings of the Korean Powder Metallurgy Institute Conference
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    • 2006.09a
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    • pp.627-628
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    • 2006
  • The present work is a study on the argon gas pressure effects of Sinter/HIP sintering on microstructure and strength of different grades of TiC-NiMo cermets. Titanium carbide in the composition of different grades of TiC-NiMo cermets was ranged from 40 to 80 wt.% and the ratio of nickel to molybdenum in the initial powder composition was 1:1, 2:1 and 4:1 respectively. On the sintered alloys, the main strength characteristic, transverse rupture strength (TRS) was measured. Furthermore, the microstructure parameters of some alloys were measured and the pressure effect on pore elimination was evaluated. All the results were compared with common, vacuum sintered alloys. The TRS values of TiC-NiMo cermets could be considerably improved by using Sinter/HIP technique, for high-carbide fraction alloys and for alloys sintered at elevated temperatures.

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Effect of Cu During Non-isothermal Hydrogen Reduction of $MoO_3$

  • Kim, Gil-Su;Kim, Dae-Gun;Oh, Sung-Tag;Suk, Myung-Jin;Kim, Young-Do
    • Proceedings of the Korean Powder Metallurgy Institute Conference
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    • 2006.09b
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    • pp.1329-1330
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    • 2006
  • The effect of Cu on the hydrogen reduction of $MoO_3$ powders was investigated by measuring the humidity change during a non-isothermal process of hydrogen reduction. The presence of Cu induced a shift in the reduction temperature and strongly affected the reduction processes of $MoO_3\rightarrowMo_4O_{11}\rightarrowMoO_2$, which comprised the contained chemical vapor transport of $MoO_x(OH)_2$. This study suggests that the surface of the Cu grains acts as a nucleation site for the reduction of $MoO_x(OH)_2$ to $MoO_2$ particles from $MoO_3$ or $Mo_4O_{11}$. Such an activated reduction process results in the deposition of Mo and $MoO_2$ particles on the surface of the Cu.

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Molybdenum Recovery from Spent Acid Solution Neutralized by Ammonia Gas (암모니아 가스 중화에 의한 폐산내 Mo 회수에 관한 연구)

  • 차우열;태순재;유진태;박융호;박종진
    • Resources Recycling
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    • v.12 no.2
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    • pp.36-44
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    • 2003
  • The present work relates to the recovery of dissolved Mo from spent mandrel dissolving acid solution by injecting ammonia gas. In order to optimize the process parameters for high yield and high purity of recovered Mo products, a bench scale and a pilot scale experiments were carried out. As a result, more than 99.5% of Mo in spent acid was recovered in the form of ammonium molybdate(4MoO$_3$.$2NH_3$.$H_2$O). The purity of Mo products recovered was higher than 99.5%. In addition, the mother liquor, residual solution after precipitation and filtration of ammonium molybdate solid particles, could be utilized as fertilizers.