نتایج جستجو برای: alkali and alkaline earth metals
تعداد نتایج: 16861401 فیلتر نتایج به سال:
the acute toxicity of salts of alkali and alkaline earth metals, such as sodium (na), potassium (k), calcium (ca) and magnesium (mg) were studied on the egg and larval stages of indian major carp labeo rohita (hamilton). the acute toxicity experiments were conducted followed by the range finding bioassay tests. the experiments were conducted in triplicates. the cumulative percentage of dead or ...
Up to date 12 complexes of triethanolamine with alkali, alkaline earth, lanthanide metals and hydrogen have been reponed. The synthesis and structure determination of these compounds is the subject of this review papacr. Moreover, the similarities and the differences of the complexes with respect to the metals and ligand are discussed.
abstract in aggregate, active forms of reactive silica with mineral names are sometimes associated with sand and gravel in concrete mixture. alkali hydroxides originated from alkalis in the cement or other resources form an alkaline silica gel with this reactive silica which becomes swallowed and expanded during time causing damage to concrete. there have been growing researches on alkaline r...
alkali and alkaline earth metals hydrogen sulfate catalyzed the one-pot three component condensation reactions of aldehydes, 1,3-dicarbonyl compounds and urea or thiourea under solvent-free conditions leading to 3,4-dihydropyrimidin-2(1h)-ones in high yields at 80 °c. our results showed that biginelli reaction not only is ph dependent, but the cation of catalyst plays an important role.
Formation of carbonate minerals by CO2 sequestration is a potential means to reduce atmospheric CO2 emissions. Vast amount of alkaline and alkali earth metals exist in silicate minerals that may be carbonated. Laboratory experiments carried out to study the dissolution rate in Pahang Sandstone, Malaysia, by CO2 injection at different flow rate in surficial condition. X-ray Powder Diffraction (X...
S-band metals such as alkali and alkaline earth metals do not undergo a superconducting transition (SCT) at ambient pressure, but their high-pressure phases do. By contrast, room-temperature stable electride [Ca(24)Al(28)O(64)](4+)⋅4e(-) (C12A7:e(-)) in which anionic electrons in the crystallographic sub-nanometer-size cages have high s-character exhibits SCT at 0.2-0.4 K at ambient pressure. I...
Computing the enthalpies of formation for alkali metal and alkaline earth metal oxides (M(x)O) and hydroxides [M(OH)(n)] using the Gaussian-n (Gn) and Weismann-n (Wn) ab initio model chemistries is difficult due to an improper treatment of core-valence electron correlation effects. Using a new model chemistry called the correlation consistent Composite Approach (ccCA), enthalpies of formation w...
Alkali and alkaline earth metals hydrogen sulfate catalyzed the one-pot three component condensation reactions of aldehydes, 1,3-dicarbonyl compounds and urea or thiourea under solvent-free conditions leading to 3,4-dihydropyrimidin-2(1H)-ones in high yields at 80 °C. Our results showed that Biginelli reaction not only is pH dependent, but the cation of catalyst plays an importan...
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