Showing papers on "Molybdenum published in 1974"
206 citations
TL;DR: The results have been interpreted to indicate inhibition of molybdenum utilization by dietary tungsten, and the inability to effect such reactivation in vitro points to the requirement for activation or modification ofmolybdate as a prerequisite for prosthetic attachment to the enzymes.
186 citations
TL;DR: The difference spectrum of oxidized native sulfite oxidase minus inactive protein revealed subtle differences in the environments of the heme prosthetic group, hydrophobic aromatic residues, and possibly sulfhydrylmolybdenum linkages.
152 citations
TL;DR: In this paper, the catalytic effects of metallic impurities on the reactivity of graphite towards water vapor and hydrogen in the temperature range 25° to 1100°C have been investigated as a function of the oxidation state of the impurity.
147 citations
Patent•
10 Dec 1974TL;DR: In this paper, an intimate mixture of titanium (Ti) as component A, with B. at least one metal selected from the group consisting of molybdenum (Mo), tungsten (W), iron (Fe), vanadium (V), nickel (Ni), cobalt (Co), copper (Cu), chromium (Cr), and uranium (U), in the form of their oxides, was used for reducing nitrogen oxides to nitrogen.
Abstract: A catalyst compositions for reducing nitrogen oxide comprising, as its chief ingredient, an intimate mixture of A. titanium (Ti) as component A, with B. at least one metal selected from the group consisting of molybdenum (Mo), tungsten (W), iron (Fe), vanadium (V), nickel (Ni), cobalt (Co), copper (Cu), chromium (Cr), and uranium (U), as component B, in the form of their oxides, and a process for reducing nitrogen oxides to nitrogen, which comprises contacting a gaseous mixture containing nitrogen oxides and molecular oxygen and a reducing gas with aforesaid catalyst compositions at an elevated temperature.
144 citations
117 citations
TL;DR: A colorimetric method was developed for determining molybdenum in seawater by solvent extraction of its dithiolate and was then applied during a nine month study of Saanich Inlet.
111 citations
110 citations
TL;DR: In this paper, the memory and threshold switching processes of polymethylmethacrylate, polystyrene, polyethylmethacetyl-poly(polybutylmethACrylate) and polybutyl poly(polymethylmethylamine) glass are described.
Abstract: Memory and threshold switching processes are described, as observed in systems consisting of thin (∼0.5 μ) polymer films (polymethylmethacrylate, polystyrene, polyethylmethacrylate, polybutylmethacrylate) between inert electrodes (graphite, molybdenum, NESA glass). The memory off‐state is highly linear, in contrast to the corresponding characteristics of multicomponent chalcogenide glasses. Switching speeds are probably similar or, at any rate, ≪10−7 sec.
95 citations
TL;DR: In this paper, the spectral properties of the reduced molybdoantimonylphosphoric acid were used to determine the optimal formation conditions and stoichiometry of reduced heteropoly acid, and it was found that a [H+]/[MoO2-4] ratio of 70± 10 was optimal for formation between 0.0008 and 0.01 M molybenum.
79 citations
Patent•
21 Nov 1974
TL;DR: In this article, the authors proposed an alloy that contains apart from such known components as copper, tin, aluminium, cadmium, zinc, titanium, chromium, zirconium, manganese, molybdenum, tungsten, iron, cobalt and nickel also vanadium, niobium, tantalum and boron in an amount of 0.001 to 80 weight percent of the total weight of all the components thereof.
Abstract: The herein-proposed alloy is characterized in that it contains apart from such known components as copper, tin, aluminium, cadmium, zinc, titanium, chromium, zirconium, manganese, molybdenum, tungsten, iron, cobalt and nickel also vanadium, niobium, tantalum and boron taken either separately or in combination, in an amount of 0.001 to 80 weight percent of the total weight of all the components thereof. The alloy is advantageous in possessing good technological characteristics, being resistant to oxidation at elevated temperatures, featuring good adhesion to all kinds of abrasive materials and giving strong brazing alloys and metallization coatings.
TL;DR: A spectrophotometric method for the quantitative determination of molybdenum and tungsten in the presence of each other in Biological materials, has been developed and possible interference by components found in biological materials was examined and shown to be negligible.
TL;DR: Ferricyanide, an artificial electron acceptor for hepatic sulfite oxidase (EC 1.8.3.1), has been shown to cause an irreversible inactivation of the enzyme by an interaction at the molybdenum center, which results in specific degradation of the polypeptide chain.
TL;DR: The upper critical fields of some ternary molybdenum sulphides were found to be extremely high as mentioned in this paper, with values above 500 kG for CuMo3S4, SnMo5S6, Pb0.9Mo5.1S6 and SnAl0.5Mo4S6 with Tc approximately 14 K.
Abstract: The upper critical fields of some ternary molybdenum sulphides are found to be extremely high. Extrapolations to low temperatures indicate values above 500 kG for CuMo3S4, SnMo5S6, Pb0.9Mo5.1S6 and SnAl0.5Mo5S6 samples with Tc approximately=14 K.
TL;DR: Klebsiella pneumoniae M5a1 grows well in the presence or absence of molybdenum in media containing excess NH(4) (+), and Tungstate competes with the molyBdate requirement during growth on N(2), providing evidence that moly bdenum is an inducer of nitrogenase synthesis.
Abstract: Klebsiella pneumoniae M5a1 grows well in the presence or absence of molybdenum in media containing excess NH4+. However, growth on N2 is completely dependent on the presence of molybdenum in the medium. Tungstate competes with the molybdate requirement during growth on N2. In molybdenum-depleted medium, neither protein component of nitrogenase is active and neither component can be detected antigenically. These data provide evidence that molybdenum is an inducer of nitrogenase synthesis.
TL;DR: In this paper, the Karlsruhe isochronous cyclotron was used to measure the (α, xn)-reactions with Mo-isotopes.
TL;DR: In this article, a study was made of the kinetics of the reduction of molybdenum trioxide by hydrogen in the temperature range 480-600 °C, and the subsequent reduction of the dioxide to metal in the range 650-800 °C.
Abstract: A study has been made of the kinetics of the reduction of molybdenum trioxide to molybdenum dioxide by hydrogen in the temperature range 480–600 °C, and the subsequent reduction of the dioxide to molybdenum metal in the range 650–800 °C. The activation energies, E , and frequency factors, A , found for a sample of sublimed molybdenum trioxide were: MoO 3 + H 2 → MoO 2 + H 2 O E = 113 kJ mol −1 , A = 4.2 × 10 −1 s −1 , MoO 2 + 2H 2 → Mo + 2H 2 O E = 98.6 kJ mol −1 , A = 2.2 × 10 −2 s −1 , The reduction of the trioxide follows a linear rate equation and an explanation of this somewhat unusual result is presented. However, reduction of the dioxide to the metal followed the more usual deceleratory path characteristic of the contracting sphere model. The results obtained in the present work are compared with the results of previous investigations.
TL;DR: In this paper, He re-emission was measured during 150 keV H+ implantation of Mo, V, and 316 SS between −90°C and 115 °C.
TL;DR: The crystal and molecular structure of a series of oxo-molybdenun di-n-propyldithiocarbamates have been studied by X-ray diffraction methods as discussed by the authors.
Abstract: The crystal and molecular structure of a series of oxo-molybdenun di-n-propyldithiocarbamates have been studied by X-ray diffraction methods. The compounds studied were di(oxo-di-n-propyldithiocarbamato) molybdenum VI (A), μ-oxo-bis-(di(oxo-di-n-propyldithiocarbamato) molybdenum V) (B), and oxo-bis-di-n-propyldithiocarbamato molybdenum IV (C). Compound A is orthorhombic, space group Pbca, with eight molecules in a unit cell having dimensions a =16.577(3) A, b =18.771(3) A and c =13.702(2) A. The molybdenum V compound (B) crystallizes in the orthorhombic non-centrosymmetric space group Pca21, with four molecules in a unit cell having parameters a =19.605(6) A, b =13.491(3) A and c =16.342(4) A. The last compound (C) is triclinic, space group P1 with two molecules in the unit cell. Its crystal parameters are a =10.183(6) A, b =13.012(9) A, c =9.208(5) A' a =71.57(5)°, β =105.81(5)° and γ =81.82(5)°. The intensities were collected by counter techniques using MoKa radiation. All structures were refin...
Patent•
02 Aug 1974TL;DR: A friction lining is formed of bounded solidified previously molten particles formed on its support by plasma deposition, and the base planes 0001 of a major proportion of the crytals in said lining are oriented in directions substantially parallel to the friction surfaces as discussed by the authors.
Abstract: A friction lining according to the invention is formed of bounded solidified previously molten particles formed on its support by plasma deposition; the base planes 0001 of a major proportion of the crytals in said lining are oriented in directions substantially parallel to the friction surfaces; the materials of which said linings are formed contain metals, metallic oxides or carbides having high melting points; they include cobalt, magnesium, neodymium, titanium, tungsten under its hexagonal form, yttrium, nickel under its hexagonal form, MoC, Mo 2 C, NbC, Nb 2 C, Ta 2 C, WC, W 2 C, V 2 C, Cr 2 O 3 , TiO 2 ; they may contain under an alloyed form proportions of non hexagonal materials, including molybdenum, chromium, aluminum, copper, iron, the non hexagonal nickel, niobium, B 4 C, TaC, TiC, Cr 3 C 2 , VC, ZrC, ZrO 2 , Al 2 O 3 , which do not affect the hexagonal structure of the alloys obtained.
TL;DR: In this article, eight yearling cattle were each dosed daily for 7 months with 30 mg Fe/kg live weight as ferric hydroxide and grazed together with eight similar, control cattle on pasture of adequate copper but low molybdenum status.
Abstract: Eight yearling cattle were each dosed daily for 7 months with 30 mg Fe/kg live weight as ferric hydroxide and grazed together with eight similar,control cattle on pasture of adequate copper but low molybdenum status.Liver and blood copper,caeruloplasmin and amine oxidase levels WCle all very markedly depressed and liver iron moderately increased by the iron treatment.There was no effect of the treatment on haemoglobin, packed cell volume. liver zinc,live-weight gain, or general health, despite a reduction in liver copper to 7 ppm and in blood copper to 0.33 mg/l on average in thc treated animals.
TL;DR: Using slowly pulsed magnetic fields up to 510 kG, it was shown that some lead-rich ternary molybdenum sulphides have critical fields above 500 kG as discussed by the authors.
Abstract: Using slowly pulsed magnetic fields up to 510 kG it is shown that some lead-rich ternary molybdenum sulphides have critical fields above 500 kG, whereas the Sn-rich compounds have critical fields of the order of 300-400 kG.
TL;DR: In this paper, a high-temperature, chemoautotrophic microorganism was studied to establish its capability for leaching molybdenite and to ascertain its response to soluble molybenite.
Abstract: A high-temperature, chemoautotrophic microorganism was studied to establish its capability for leaching molybdenite and to ascertain its response to soluble molybdenum. Experimental results confirm that the organism can tolerate 2000 ppm hexavalent molybdenum and can grow when the concentration of soluble molybdenum is 750 ppm. A molybdenite concentrate is leached at a maximum rate of 6.6 mg Mo solubilised/1./day; this rate is maximised by supplementing the medium with 0.02% yeast extract and 1% iron(II) sulphate. Batch reactor-leaching suppresses the rate of molybdenum solubilisation; the original leaching rate can be re-established by periodic replacement of the suspending medium. Some organic compounds enhance the leaching rate, but combinations of these compounds are not additive. Sulphur is inhibitory to molybdenite leaching; pyrite suppresses molybdenum solubilisation if the concentration of pyrite exceeds 50% of the total solid substrate. Molybdenite ore is successfully leached. Molybdenite waste and tailings contain acid-consuming gangue and lime, respectively, which raise the pH well above optimum for biogenic leaching. Hence, biogenic leaching of waste and tailings is not successful by the technique employed herein. Direct observations of the high-temperature microorganism on molybdenite fines illustrate colonial growth and developmental characteristics in a microbial—mineral interaction. The organism responds to hexavalent molybdenum by reducing this metal to the pentavalent state in aerobic and nitrogen gas atmospheres.