نتایج جستجو برای: vanadium v oxide
تعداد نتایج: 478824 فیلتر نتایج به سال:
Vanadium is distributed widely and scarcely (150 ppm) on the earth. Its major applications are in steelmaking, dye-production and catalyst-fabrication industries. With the ever-increasing demand for this metal, secondary resource-exploitation of such waste materials as spent catalysts is recommended. Many reactions are involved in vanadium-extraction from these resources. Since roasting in comp...
Neutral vanadium oxide clusters are studied by photoionization time-of-flight (TOF) mass spectroscopy, electronic spectroscopy, and density functional theory (DFT) calculations. Mass spectra of vanadium oxide clusters are observed by photoionization with lasers of three different wavelengths: 118, 193, and 355 nm. Mechanisms of 118 nm single photon ionization and 193 and 355 nm multiphoton ioni...
Single-photon ionization through vacuum ultraviolet (VUV, 10.5 eV) and soft X-ray (extreme ultraviolet, EUV, 26.5 eV) laser radiation is successfully employed for the study of the reactions of neutral vanadium oxide clusters (V(m)O(n)) with sulfur dioxide (SO2) in the gas phase. V(m)O(n) clusters are generated by reaction of a laser-generated vanadium plasma with O2 in a supersonic expansion. T...
Vanadium oxide cluster anions (V(x)O(y)(-), x = 2-3; y = 3-7) are produced by laser ablation and reacted with water in a fast flow reactor. A time-of-flight mass spectrometer is used to detect the cluster distribution before and after the reactions. Reaction channels of molecular hydrogen elimination (for V(2,3)O(3)(-)), water association (for V(2)O(5)(-) and V(3)O(6,7)(-)) and the coexistence ...
Some ascidians accumulate vanadium in vanadocytes, which are vanadium-containing blood cells, at high levels and with high selectivity. However, the mechanism and physiological significance of vanadium accumulation remain unknown. In this study, we isolated novel proteins with a striking homology to glutathione transferases (GSTs), designated AsGST-I and AsGST-II, from the digestive system of t...
The interaction of vanadium oxide and niobium oxide with A1203 and TiO2 supports is examined with Raman spectroscopy. The Raman spectra of the supported metal oxides reveal that the strong interaction of the metal oxides with AI203 and TiO2 supports results in the formation of two-dimensional surface metal oxide overlayers. The surface vanadium oxide overlayers are unstable to high calcination ...
A new vanadium oxide, potassium bis-(dioxovanad-yl) phosphate, β-K(VO2)2(PO4), has been synthesized by a solid-state reaction. In the title compound, the [V2PO8] framework is built up from infinite pyramidal [V2O8]∞ and [VPO7]∞ chains linked together by V-O-P bridges, leading to a three-dimensional framework which delimits two types of inter-secting tunnels running along [100] and [010] in whic...
Oxo- and imido-vanadium(V) metal complexes supported by bis(phenolate)-functionalized N-heterocyclic carbene (NHC) ligands were synthesized structurally identified. In the presence of [(Ph3P)2N]Cl ([PPN]Cl), saturated NHC oxo-vanadium showed activity in coupling CO2 cyclohexene oxide (CHO) into cis-cyclohexene carbonate (cis-CHC). More importantly, complex bearing less electron-donating benzann...
an isolate from polluted soil identified as aspergillus sp. ms-100 was able to consume vanadium oxide octaethyl porphyrin as a model for protoporphyrins in crude oil. the isolate degrades about 55% of vanadium oxide octaethyl porphyrin (vooep) under optimum conditions during 7 days. the release of more than 0.96 mgl-1 of free vanadium into the aqueous phase was confirmed using atomic absorption...
The present research investigated the sol–gel preparation, dielectric and ferroelectric properties of PZT films doped with 5 mol% vanadium oxide. Stable PZTV sols can be readily formed, and homogeneous, micrometer thick and pinhole-free PZTV films were obtained by using spin coating followed with rapid annealing. The X-ray diffraction patterns revealed that no parasitic or secondary phases were...
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