نتایج جستجو برای: cerium
تعداد نتایج: 3705 فیلتر نتایج به سال:
AIM Cerium as a trace element in the periodic table is a member of the lanthanide group. Cerium ionic radius and its binding properties are similar to ferric ions, which may be bound to transferrin. So it can be considered as a competitive element to iron and can interfere with iron absorption. The aim of this study was to investigate the inhibitory effect of Cerium in presence of transferrin o...
The activity of cerium alkoxide complexes supported by a Schiff base ligand was controlled using redox reagents during the ring-opening polymerization of L-lactide. The rate of L-lactide polymerization was modified by switching in situ between the cerium(III) and cerium(IV) species.
In the current study cerium or galliumcontaining silicate based 13-93 bioactive glass powders were prepared using sol-gel method. Cerium and gallium ions were chosen due to their well-known therapeutic actions and antimicrobial properties. Effect of cerium and gallium substitution (up to 5w%) on the in vitro bioactivity, and mechanical properties of the prepared powders and scaffolds were asses...
A simple, rapid and sensitive spectrophotometric method has been proposed for the determination of cerium(IV) using a phenothiazine derivative, propionyl promazine phosphate (PPP). This method is based on the formation of a red-colored radical cation upon a reaction of PPP with cerium(IV) in a phosphoric acid medium having maximum absorbance at 513 nm. Beer's law is valid over the concentration...
A retrospective study was conducted to evaluate lung retention of particles containing cerium in subjects with and without previous occupational exposure to mineral dusts. Analytical transmission electron microscopy was performed on 459 samples of bronchoalveolar lavage (BAL) fluid and 75 samples of lung tissue. Study of the distribution of mineralogical species in human samples showed that par...
In the paper, we claim to observe the optical activity of cerium in a triply doped yttrium oxide system displaying both upconverting and downshifting properties. The singly-doped Y2O3:Ce 3+ system has already been investigated by many groups, with controversial results, as stated in our paper. Some groups suggested an emission centered on cerium ions, while others proposed a defect-related emis...
Cerium oxide (ceria, CeO 2-x where x is 0 to 0.5) has been one of the most widely used heterogeneous catalysts particularly in three way catalytic converters. Most of the catalytic traits can be attributed to two properties of ceria: first, the high mobility and storage capacity of oxygen within the lattice; second, the ease with which cerium changes between Ce 3+ and Ce 4+ states. These proper...
A series of alkali metal cerium diphenylhydrazido complexes, Mx(py)y[Ce(PhNNPh)4], M 1⁄4 Li, Na, and K, x 1⁄4 4 (Li and Na) or 5 (K), and y1⁄4 4 (Li), 8 (Na), or 7 (K), were synthesized to probe how a secondary coordination sphere would modulate electronic structures at a cerium cation. The resulting electronic structures of the heterobimetallic cerium diphenylhydrazido complexes were found to ...
The influence of a cerium additive on the kinetics of oxidation and size distribution of ultrafine diesel particles was studied using a high-temperature oxidation-tandem differential mobility analysis method over the temperature range 300–700 ◦C. The addition of cerium to the diesel fuel was observed to cause significant changes in numberweighted size distributions, light-off temperature, and k...
Traditional nanostructured design of cerium oxide catalysts typically focuses on their shape, size, and elemental composition. We report a different approach to enhance the catalytic activity of cerium oxide nanostructures through engineering high density of oxygen vacancy defects in these catalysts without dopants. The defect engineering was accomplished by a low pressure thermal activation pr...
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