نتایج جستجو برای: earth cation
تعداد نتایج: 148521 فیلتر نتایج به سال:
Following a given classi®cation of geomagnetic activity, we obtained aa index values for the Maunder minimum (1645±1715). It is found that the recurrent and ̄uctuating activities were not appreciable and that the shock activity levels were very low. The aa index level was due almost entirely to the quiet days. Calculated average solar-wind velocities were 194.3 km s from 1657 to 1700 and 218.7 ...
The effect of elevated divalent cation concentration on the kinetics of sodium ionic and gating currents was studied in voltage-clamped frog skeletal muscle fibers. Raising the Ca concentration from 2 to 40 mM resulted in nearly identical 30-mV shifts in the time courses of activation, inactivation, tail current decay, and ON and OFF gating currents, and in the steady state levels of inactivati...
Choline was determined in infant formula by ion chromatography with suppressed conductivity detection. Samples were digested with 1M hydrochloric acid, filtered, diluted, and injected into the chromatographic system. Choline and the alkali and alkaline earth metals were separated on a high-resolution cation-exchange column and detected by suppressed conductivity. The method was linear between 2...
Calcium is an attractive material for the negative electrode in a rechargeable battery due to its low electronegativity (high cell voltage), double valence, earth abundance and low cost; however, the use of calcium has historically eluded researchers due to its high melting temperature, high reactivity and unfavorably high solubility in molten salts. Here we demonstrate a long-cycle-life calciu...
This paper demonstrates the possibility of creating oxygen deficiency in perovskites A+3B+3O3 by introducing two types cations with different charges into B-sublattice. For this, it is proposed to introduce a two-charged cation, for example, Zn2+, as an alternative alkaline earth metals. Previously, this was demonstrated aluminate LaAlO3 and indate LaInO3. In article, we have focused on modific...
The surface and near-surface chemical composition of electroceramic materials often shows significant deviations from that of the bulk. In particular, layered materials, such as cation-ordered LnBaCo2O(5+δ) perovskites (Ln = lanthanide), undergo surface and sub-surface restructuring due to the segregation of the divalent alkaline-earth cation. These processes can take place during synthesis and...
More than 50 uranyl minerals, phases containing U as the uranyl UO2 2+ cation, and hydroxide, carbonate, phosphate, and silicate anions, H2O, and alkali and alkaline earth cations, occur in nature and as corrosion products of spent nuclear fuel. Despite their importance and the need to understand their thermodynamics to predict uranium solubility, fate, and transport in the environment, reliabl...
The extraction of rare earth elements (REEs) from nitric acid solution with a triphosphine trioxide (TPO) is presented. Performances of such a ligand in ionic liquids vs. a classical solvent (benzyl ether) are compared. TPO seems to be 10 to 100 times more efficient when it is dissolved in ionic media whatever the concentration of nitric acid involved. Mechanistic investigations reveal that cat...
La4Cu3MoO12 is a new (ABO3)n)4 cuprate with mixed B-cations in a ratio of 1:3. When synthesized at ambient pressure, the structure is not perovskite as expected but rather a homeotype of YAlO3, a rare-earth hexagonal phase. While the P63/mmc and Pmnm space groups can be used to model average structures which appear in quenched samples; powder, electron, and neutron diffraction data all confirm ...
The general approach to a novel class of functionalized ionic liquids 4-6 bearing grafted diphenylcarbamoylmethylphosphine oxide complexing groups in the cation has been elaborated. The synthetic route comprises the preparation of the intermediate (diphenylphosphorylmethylcarbamoyl)propylimidazole 3, followed by sequential quaternization by alkyl halides (chlorides or bromides) and anionic exch...
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