نتایج جستجو برای: co3
تعداد نتایج: 1341 فیلتر نتایج به سال:
Potentiometric measurements of Yttrium and Rare Earth Element (YREE) complexation by carbonate and bicarbonate indicate that the quality of carbonate complexation constants previously obtained via solvent exchange analyses are superior to characterizations obtained using solubility and adsorptive exchange analyses. The results of our analyses at 25°C are combined with the results of previous so...
While nature exerts precise control over the size and chemical composition of minerals, this is still a challenging task for artificial syntheses. Despite its significance, until now, there are still no reports on colloidal mineral nanoparticles in the subnanometer range. Here we developed a general gas diffusion strategy using 10,12-pentacosadiynoic acid as a ligand and ethanol as a solvent to...
Intracellular pH (pHi) in squid giant axons recovers from acid loads by means of a Na(+)-dependent Cl-HCO3 exchanger, the actual mechanism of which might be exchange of: (i) external Na+ and HCO3- for internal Cl- and H+, (ii) Na+ plus two HCO3- for Cl-, (iii) Na+ and CO3= for Cl-, or (iv) the NaCO3- ion pair for Cl-. Here we examine sensitivity of transport to changes of extracellular pH (pHo)...
We study the magnetic susceptibility of mixed-valent La2−xSrxCoO4 single crystals in the doping range of 0.5 x 0.8 for temperatures up to 1000 K. The magnetism below room temperature is described by paramagnetic Co2+ in the high-spin state and by Co3+ in the nonmagnetic low-spin state. At high temperatures, an increase in susceptibility is seen, which we attribute to a temperature-induced spin-...
Introduction: The results of a number of studies seem to indicate that CO3 chondrites can be subdivided into a metamorphic series analogous to that seen in ordinary chondrites [1,2,3]. It has been suggested that this sequence is the result of hydrothermal alteration on the CO parent body [4]. One particularly intriguing feature of CO3 chondrites is the reported general correlation between whole...
While nature exerts precise control over the size and chemical composition of minerals, this is still a challenging task for artificial syntheses. Despite its significance, until now, there are still no reports on colloidal mineral nanoparticles in the subnanometer range. Here we developed a general gas diffusion strategy using 10,12-pentacosadiynoic acid as a ligand and ethanol as a solvent to...
The reaction of Cu(ClO4)(2).6H2O and 1,2-bis(4-pyridyl)ethane (bpe) in basic aqueous solution yields a 3D compound, {[Cu3(CO3)2(bpe)3].2ClO4}n (1) through the atmospheric fixation of CO2 composing Cu(CO3) kagomé layers pillared by the bpe linker that exhibit weak antiferromagnetic interaction in the kagomé layer and interlayer ferromagnetic coupling at low temperature.
It is well known that hydrogen peroxide (H2O2)-induced copper-catalyzed fragmentation of proteins follows a site-specific oxidative mechanism mediated by hydroxyl radical-like species (i.e. Cu(I)O, Cu(II)/*OH or Cu(III)) that ends in increased carbonyl formation and protein fragmentation. We have found that the nitrone spin trap DMPO (5,5-dimethyl-1-pyrroline N-oxide) prevented such processes b...
Low-cost and high-performance advanced electrocatalysts for direct methanol fuel cells are of key significance for the improvement of environmentally-pleasant energy technologies. Herein, we report the facile synthesis of cobalt phosphate (Co3(PO4)2) nanospheres by a microwave-assisted process and utilized as an electrocatalyst for methanol oxidation. The phase formation, morphological surface ...
Ferromagnesite [(Mg,Fe)CO3] has been proposed as a candidate host mineral for carbon in the Earth’s mantle. Studying its physical and chemical properties at relevant pressures and temperatures helps our understanding of deep-carbon storage in the planet’s interior and on its surface. Here we have studied high-pressure vibrational and elastic properties of magnesian siderite [(Mg0.35Fe0.65)CO3] ...
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