a series of ethylene-propylene-2-ethylidenebicyclo [2.2.1] hept.5-ene terpolymers (epdm) have been prepared using a vocl3/al2et3cl3 catalyst under various al/v ratios and diene concentrations via solution polymerization and characterized by ftir, mooney viscosity (ml1+4,125oc), and thermal gravimetery analyzing. the polymerization yield was seen to increase with augmentation of the al/v ratio a...

Vanadium phosphorus oxides are used as catalysts in the selective oxidation of n-butane to maleic anhydride. The working catalyst comprises besides the main pyrophosphate phase in which the vanadium is in a 4+ oxidation state also a, predominantly preparation dependent, amount of different pentavalent vanadylorthophosphate phases. In order to elucidate the role of the pentavalent phases it is n...

The effect of the irradiation with Al Ka X-rays during an XPS measurement upon the surface vanadium oxidation state of a fresh in vacuum cleaved V2O5(001) crystal was examined. Afterwards, the surface reduction of the V2O5(001) surface under Ar + bombardment was studied. The degree of reduction of the vanadium oxide was determined by means of a combined analysis of the O1s and V2p photoelectron...

Neutral vanadium, niobium, and tantalum oxide clusters are studied by single photon ionization employing a 26.5 eV/photon soft x-ray laser. During the ionization process the metal oxide clusters are almost free of fragmentation. The most stable neutral clusters of vanadium, niobium, and tantalum oxides are of the general form (MO2)0,1(M2O5)y. M2O5 is identified as a basic building unit for thes...

V2O5 based materials are attractive cathode alternatives due to the many oxidation state switches of vanadium bringing about a high theoretical specific capacity. However, significant capacity losses are eminent for crystalline V2O5 phases related to the irreversible phase transformations and/or vanadium dissolution starting from the first discharge cycle. These problems can be circumvented if ...

in this research, nano materials with tubular structures are added to sae 20w50 engine oil to study the rate of their effects on the properties of engine oil. multi-walled carbon nanotubes (mwcnts) and vanadium oxide nanotubes (vonts) has been used as two different additive materials, one of them is carbonic and the other is metallic oxides and their effect on  different parameters containing v...

Vanadium haloperoxidases catalyse the oxidation of halides leading to halogenation of substrates or, in the absence of suitable substrates, to oxidation of hydrogen peroxide into singlet oxygen and water. Furthermore, V-haloperoxidases are capable to give enantioselective sulfoxidation under the appropriate conditions. The most interesting model compounds that have been synthesised and studied ...

oxidation of ethylene to ethylene oxide over silver catalyst and selenium modified catalyst has been studied by continuous flow and pulse techniques over the temperature range of 230-280 °c. the results are discussed in terms of reaction mechanisms proposed by others, rejecting mechanisms which involve peroxide formation. it has been shown that not only selectivity towards ethylene oxide produc...

Boosted by the rapid advances of science and technology in the field of energy materials, Li-ion batteries have achieved significant progress in energy storage performance since their commercial debut in 1991. The development of nanostructured electrode material is regarded as one of the key potentials for the further advancement in Li-ion batteries. This feature article summarizes our recent e...

Vanadium oxides are highly valued as electrochromic materials because of their multicolor capabilities. However, practical applications have been limited due to challenges such the dissolution vanadate into aqueous electrolytes, leading poor long-term stability. Herein, a solution is proposed issue by utilizing hybrid electrolyte consisting tetraethylene glycol dimethyl ether (TEGDME) and water...