نتایج جستجو برای: vanadium
تعداد نتایج: 7597 فیلتر نتایج به سال:
Diabetes mellitus is accompanied by hormonal and neurochemical changes that can be associated with anxiety and depression. Both diabetes and depression negatively interact, in that depression leads to poor metabolic control and hyperglycemia exacerbates depression. We hypothesize one novel vanadium complex of vanadium-enriched Cordyceps sinensis (VECS), which is beneficial in preventing depress...
The layered oxides of vanadium and molybdenum have been studied for close to 40 years as possible cathode materials for lithium batteries or electrochromic systems. The highly distorted metal octahedra naturally lead to the formation of a wide range of layer structures, which can intercalate lithium levels exceeding 300 Ah/kg. They have found continuing success in medical devices, such as pacem...
The vanadium-vanadium interactions in the polygonal aggregates of d¹ vanadium(IV) atoms, with a total of 4k + 2 vanadium electrons (k an integer) imbedded in an electronically inactive borate matrix in certain vanadoborate structures are analogous to the ring carbon-carbon interactions in diamagnetic planar cyclic hydrocarbons. They thus represent a high-spin analogue of aromaticity. Thus, the ...
We examined the electrical and optical properties of vanadium-doped GaAs grown by metalorganic vapour phase epitaxy using vanadium tetrachloride (VCl4) as a novel dopant source. Samples with various vanadium incorporations were investigated. All samples were n type. The electron concentration dependence on the VCl4 flow rate was established. At 15 K, by comparison with undoped layers grown in t...
In this paper, the composite additive of CaF2/CaO was used to extract vanadium from stone coal, and the effect of roasting and leaching kinetics were studied. The purpose of this manuscript is to realize and improve the vanadium recovery from stone coal using the composite additive. The experimental results indicated that the roasted clinker can be obtained under the conditions of CaF2/CaO at a...
A solvent-extraction spectrophotometric technique is proposed as a new method for determination of trace quantities of vanadium. Sodium salt of 2-mercapto-pyridine-N-oxide (thione) forms a complex with vanadium instantaneously. The purple 1:2 complex is formed of pH 2.3, easily extracted in chloroform and shows strong absorbance at 500 nm. The extracted complex is found to obey Beer's law i...
Chemiluminescence from the vanadium and potassium permanganate reaction was studied under acidic conditions to develop a sensitive method for vanadium determination using the formaldehyde enhancement effect. The method was successfully applied to the determination of vanadium in seawater. Experimental parameters were optimized, including acid concentration, potassium permanganate and formaldehy...
The selective oxidation and halogenation of nitroaromatics is a difficult task both chemically and enzymatically. We have discovered that vanadium chloroand bromoperoxidases from Curvularia inaequalis and Corralina officinalis, respectively, are capable of catalyzing the hydroxylation, halogenation, and demethylation of 2,4,6-trinitrotoluene (TNT) under alkaline conditions. At pH 8, the convers...
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