• Bulletin of the Korean Chemical Society
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• v.23 no.3
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• pp.395-399
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• 2002

The voltammetric behavior of spontaneously adsorbing Mo layers on Pt(111) and Pt(100) electrodes has been studied to estimate the number of electrons involved in the electrochemical processes of spontaneously adsorbed Mo and the number of the bloc ked Pt sites for hydrogen adsorption. On Pt(111) and Pt(100) surfaces, the spontaneously adsorbed Mo layers showed redox peaks at 0.10 V and 0.15 V, respectively, and continuous current-potential waves in the conventional hydrogen region. Since the potential range of the Mo redox processes on both surfaces overlapped partially with the potential range of hydrogen adsorption, the variation in the ratio of the total charge of Mo and H ($Q_H$ +$Q_{MO}$) to the hydrogen charge of clean Pt electrode ($Q_H^0$) was analyzed. From the analysis, six electrons were estimated to be involved in the electrochemical processes of the spontaneously adsorbed Mo, and four Pt sites for hydrogen adsorption were calculated to be blocked by one adsorbed Mo atom. Based on these figures and the pH dependence of the Mo redox processes, we have proposed an electrochemical equation for the spontaneously adsorbed Mo. This electrochemical equation led us to conclude that the saturation coverage of the spontaneously adsorbed Mo is 0.25. The coverage of Mo less than 0.25, however, could not be determined voltammetrically due to the convolution of the charges of Mo and H.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.5 no.2
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• pp.114-117
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• 2004

Rates of $H_2$ uptake into $Pt/MoO_3$ were measured for the noncalcined and $200^{\circ}C$ calcined $Pt/MoO_3$. Amount of $H_2$ uptake for $200^\circ{C}$calcined $Pt/MoO_3$ was greater than the amount of noncalcined $Pt/MoO_3$. From these two experiments, it was found that the rates of $H_2$ desorption were proportional to the increase of desorption temperature. XPS demonstrated that Cl reduced more faster in ITR after calcination at $200^{\circ}C$. This inducd smaller amount of residual chlorine at adlineation sites between Pt and $MoO_3$ substrates. This resulted in opening the more channel of hydrogen pathway into more $MoO_3$particles and controled the kinetics of hydrogen uptake.

• Journal of the Korean institute of surface engineering
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• v.39 no.6
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• pp.245-249
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• 2006

In this study, ternary Ti-Mo-N and new quaternary Ti-Mo-Si-N coatings were synthesized on steel substrates(AISI D2) and Si wafers by a hybrid coating system of arc ion plating (AIP) using Ti target and d.c. magnetron sputtering technique using Mo and Si targets in $N_2/Ar$ gaseous mixture. Ternary Ti-Mo-N coatings were substitutional solid-solution of (Ti, Mo)N and showed maximum hardness of approximately 30 GPa at the Mo content of ${\sim}10$. %. The Ti-Mo-Si-N coating with the Si content of 8.8 at. % was a composite consisting of fine (Ti, Mo)N crystallites and amorphous $Si_3N_4$ phase. The hardness of the Ti-Mo-Si(8.8 at. %)-N coatings exhibited largely increased hardness value of ${\sim}48$ GPa due to the microstructural evolution to the fine composite microstructure and the refinement of (Ti, Mo)N crystallites. The average friction coefficient of the Ti-Mo-Si-N coatings largely decreased with increase of Si content. The microstructures of Ti-Mo-Si-N coatings were investigated with instrumental analyses of XRD, XPS, and HRTEM in this work.

• Journal of the Korean Chemical Society
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• v.18 no.4
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• pp.267-271
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• 1974

The tetradentate schiff base, N,N'-bis(salicylaldehyde)-ethylene diimine has been reacted with a series of Mo(IV), Mo(V), Mo(IV), and Mo(III) oxidation states to form new Complexes; $[MoO_2(C_{16}H_{14}O_2N_2)], (MoO(C_{16}H_{14}O_2N_2)]_2O, (Mo(SCN)(C_{16}H_{14}O_2N_2)]_2O, and (Mo(H_2O)(C_{16}H_{14}O_2N_2)]_2O.$ These complexes have hexa coordinated configurations and the mole ratio of these ions to the ligand was 1:1. These complexes have been identified by visible spectra, infrared specra, T.G.A., D.T.A., and elemental analysis.

• Proceedings of the Materials Research Society of Korea Conference
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• 2009.05a
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• pp.53.2-53.2
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• 2009

몰리브덴(Mo)은 우수한 전기전도도와 고온 안정성으로 인해 전자부품의 전극으로 널리 사용되고, 미래 에너지인 태양전지 분야에서 CIS계 화합물박막태양전지의 후면전극으로 이용되고 있는 재료로서 현재 증착 방법으로는 D.C. sputtering이 가장 널리 이용되고 있다. 또한 $MoO_3$ 분말이 Mo 분말로 수소 환원되는 과정은 $MoO_3+H_2{\rightarrow}MoO_2+H_2O$ 와 $MoO_2+2H_2{\rightarrow}Mo+2H_2O$의 2단계를 통해서 수행되며 이중 첫 번째 단계에서 $MoO_3(OH)_2$라는 기상을 통해 지배적으로 일어난다고 알려져 있고 이를 화학증기수송(Chemical vapor transport : CVT)이라고 한다. 본 연구에서는 $MoO_3$분말의 수소 환원 과정 중에 발생하는 기상인 $MoO_3(OH)_2$을 이용하여 몰리브덴 옥사이드 박막을 증착하고 이를 다시 수소분위기에서 수소 환원하는 증착 방법을 통해 균일하고 부착성이 우수한 Mo 박막을 제조하고자 하였다. 기판으로 사용된 Glass를 $MoO_3$ 분말 위에 홀더를 이용하여 $MoO_2$ 박막을 증착하고 이를 다시 수소분위기에서의 수소 환원을 통해 Mo 박막을 성공적으로 제조하였다. 제조된 Mo박막의 결정구조 및 미세조직을 XRD 와 SEM을 통해 분석하였다.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.16 no.4
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• pp.172-179
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• 2006

When $Al_2O_3-MoO_3$ mixture is reduced, $MoO_3$ is only reduced to Mo at $900^{\circ}C$. But a compound between $Al_2O_3$ and Mo is not formed up to $1300^{\circ}C$. In the case of $Al_2O_3-MoO_3-MnO_2$ mixture, an intermediate compound $Mn_2Mo_3O_8$ is firstly formed at $900^{\circ}C$ and changes to $MnAl_2O_4$ at $1100^{\circ}C{\sim}1300^{\circ}C$. $Al_2O_3/Mo/MnO_2$ composite are manufactured by a selective reduction process in which Mo is only reduced in the powder mixture of $Al_2O_3,\;MoO_3\;and\;MnO_2$ oxide. For $Al_2O_3/Mo$ composite, the average grain size was not changed with increasing Mo content because of inhibition of grain growth of $Al_2O_3$ matrix in the presence of Mo particles. Fracture strength increased with increasing Mo content due to phenomenon of grain growth inhibition of $Al_2O_3$ matrix. Hardness decreased because of a lower hardness value of Mo, whereas fracture toughness increased. For $Al_2O_3,\;Mo\;and\;MnO_2$ composite, grain growth was facilitated by MnOB and it showed a lower fracture strength because of grain growth effect with increasing Mo and $MnO_2$ content. Hardness decreased because of the grain growth of matrix and coalesced Mo particles to be located in grain boundary, whereas fracture toughness increased.

• Applied Chemistry for Engineering
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• v.9 no.1
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• pp.101-106
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• 1998

Two types of CoMo/zeolite as well as $NiMo/{\gamma}-Al_2O_3$ were prepared and their activities and selectivities of low-temperature dibenzothiophene(DBT) hydrodesulfurization(HDS) were studied in high pressure fixed bed reactor. The HDS activities of CoMo/zeolites were higher than that of $NiMo/{\gamma}-Al_2O_3$ at temperatures below $225^{\circ}C$ while they were lower than that of $NiMo/{\gamma}-Al_2O_3$ at temperatures higher than $275^{\circ}C$. The main products from $NiMo/{\gamma}-Al_2O_3$ were biphenyl and cyclohexylbenzene. The product distribution of CoMo/zeolite catalysts was different from that of $NiMo/{\gamma}-Al_2O_3$. It is speculated that DBT is converted to alkylcyclohexane over zeolite based catalysts through both alkylation and hydrogenation reactions. The crystal structure of molybdenum was $MoO_3$ in fresh zeolite support while mixtures of $MoO_3$ and $MoS_2$ were observed in the aged catalyst.

• Journal of Korea Foundry Society
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• v.10 no.3
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• pp.225-234
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• 1990

Spheroidal graphite cast irons which are Fe-3%C-(4－6)%Si-(0－0.5)%Mo were studied to improve not only heat resistance but also mechanical properties. With increasing Mo content, the graphitization was decreased and carbide volume fraction was increased. The graphite spheroidization ratio was not decreased in Fe-3%C-6%Si-Mo system cast iron with increasing Mo content, but that was decreased in Fe-3%C-4%Si-Mo system and Fe-3%C-5%Si-Mo system cast irons. Hardness was increased with the Si and Mo contents. At constant Si content, tensile strength was increased with increasing Mo content, but that was decreased at 6%Si. In the experiment of oxidation, weight gain was decreased as the Si and/or Mo content increased, but increased at 1.5%Mo content.

• Bulletin of the Korean Chemical Society
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• v.19 no.12
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• pp.1363-1368
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• 1998

Mo/γ-Al2O3 catalysts were prepared by impregnation method in various conditions to identify the states of surface Mo species. TPR (Temperature-Programmed Reduction) and Raman spectroscopy were applied to analyze the surface Mo species. TPR analysis revealed that MoO3 was reduced to Mo through MoO2, the intermediate state and the increase of Mo loading enhanced the reducibility of Mo oxide till the formation of monolayer coverage. High temperature calcination induced oxygen defects in MoO3 giving their unstable states for easier reduction. Raman spectroscopy analysis showed that the increase of Mo loading induced the polymeric Mo oxide.

• Asian-Australasian Journal of Animal Sciences
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• v.22 no.12
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• pp.1654-1660
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• 2009

This study was conducted to investigate the effects of different fattening periods i.e. 25, 27 and 29 months of age (25 mo, 27 mo and 29 mo), on feed consumption, body weight gain, carcass parameters, and lipogenic gene expression in 45 Korean native steers (Hanwoo). Daily DM intake was higher in steers on 29 mo compared with those on 25 mo or 27 mo. Daily body weight gain was higher in steers on 25 mo compared with those on 27 mo or 29 mo during fattening and overall experimental periods. Therefore, feed conversion ratio was lower in 25 mo compared with 27 mo or 29 mo during the fattening and whole experimental periods. As expected, slaughter and carcass weights were higher in the order of 29 mo>27 mo>25 mo. Carcass yield grade was relatively lower in 29 mo reflecting higher back fat thickness compared with other treatments, while carcass quality grade was not largely influenced by the treatments. By investigation with an ultra-sound scanning technique, the marbling score was significantly and numerically higher in 25 mo compared with 27 mo or 29 mo. The mRNA levels of stearoyl-CoA desaturase (SCD) gene were gradually increased in the late fattening stages (p<0.01) and mRNA of acetyl-CoA carboxylase (ACC), ATP citrate lyase (ACL) and glucose transporter 4 (GLUT4) gene were highly expressed in 29 mo compared with 25 mo and 27 mo (p<0.05). However, gene expressions of adipocyte fatty acid binding protein 4 (FABP4) and lipoprotein lipase (LPL) were not significantly different among the treatments. Thus the present results indicated that different fattening period has no major effect on carcass characteristics, although 25 mo had a lower carcass weight compared with 27 mo or 29 mo.