نتایج جستجو برای: tungsten compounds
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Gas tungsten arc welding (GTAW) or Tungsten inert gas welding (TIG) is one of the widely used techniques for joining ferrous and non-ferrous metal.Gas tungsten arc welding process,consist of non-consumable tungsten electrode which is used to provide the arc for welding. During the welding cycle a shield of inert gas expels the air from the welding area and prevents oxidation of the electrode, w...
Practical application of hydrogen production from water splitting relies strongly on the development of low-cost and high-performance electrocatalysts for hydrogen evolution reaction (HER). The previous researches mainly focused on transition metal nitrides as HER catalysts due to their electrical conductivity and corrosion stability under acidic electrolyte, while tungsten nitrides have report...
Here, we report that the postsynthesis nitridation of tungsten oxide nanowires can result in single crystal nitride nanowires when the initial diameters of the nanowires are less than 10 nm. For nanowires with diameters greater than 10 nm, the nitridation of nanowires resulted in polycrystalline but highly oriented tungsten nitride domains in nanowires. Partially nitrided nanowires show an epit...
This study investigates the photocatalytic water splitting performance for N i x W 6 S e 8 ( = 1 , 2 3 4 ) ${\mathrm{N}}{{\mathrm{i}}_{\mathrm{x}}}{{\mathrm{W}}_6}{\mathrm{S}}{{\mathrm{e}}_8}\;( {x 1, 2, 3, 4} )$ Chevrel phases with chemical formula MxMo6Ch8, where M is a metal and Ch chalcogen, being 0, or 4. Density Functional Theory (DFT) used to ${\mathrm{N}}{{\mathrm{i}}_{\mathrm{x}}}{{\ma...
Tungsten (atomic number 74) and the chemically analogous and very similar metal molybdenum (atomic number 42) are minor yet equally abundant elements on this planet. The essential role of molybdenum in biology has been known for decades and molybdoenzymes are ubiquitous. Yet, it is only recently that a biological role for tungsten has been established in prokaryotes, although not as yet in euka...
In this work, a study of the influence of the starting materials and the processing time used to develop W/Cu alloys is carried out. Regarding powder metallurgy as a promising fabrication route, the difficulties in producing W/Cu alloys motivated us to investigate the influential factors on the final properties of the most industrially demanding alloys: 85-W/15-Cu, 80-W/20-Cu, and 75-W/25-Cu al...
Formate dehydrogenase molybdenum and tungsten sites--observation by EXAFS of structural differences.
Preliminary EXAFS data has been collected on the molybdenum (K-edge) in C. pasteurianum formate dehydrogenase and the tungsten (LIII-edge) in C. thermoaceticum formate dehydrogenase. In the presence of dithionite, the tungsten enzyme was devoid of W = O bonds, and exhibited average W-(O, N) and W-S bond lengths of 2.13 +/- 0.03 A and 2.39 +/- 0.03 A, respectively. In sharp contrast, the C. past...
Fischer carbene complexes of tungsten with substituents containing up to two additional different transition metals, with all the metals in electronic contact with the carbene carbon atom, were synthesised and studied both in solution and in the solid state. For the complexes of the type [W(CO)(5){C(OR')R}], the substituents chosen were heteroaromatic 2-benzo[b]thienyl (2-BT), or 2-BT π-bonded ...
The present research concerns an electrodeposited cobalt-tungsten alloy coating on graphite fibers. Annealed and unannealed coated fibers were analyzed by scanning electron microscopy/energy dispersive x-ray spectroscopy (SEM/EDS), x-ray diffraction (XRD), and transmission electron microscopy (TEM). The mole fraction of tungsten in the as-deposited cobalt-tungsten coating was found to be (7.10 ...
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