نتایج جستجو برای: cerium compounds
تعداد نتایج: 230132 فیلتر نتایج به سال:
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...
Treatment of Ce[N(SiHMe(2))(2)](3)(thf)(2) with the chlorinating agents PhICl(2), Ph(3)CCl or C(2)Cl(6) gave the homoleptic Ce(IV) silylamide Ce[N(SiHMe(2))(2)](4). When performed in the absence of donating (solvent) molecules, the trivalent cluster Ce(5)[N(SiHMe(2))(2)](8)Cl(7) was isolated.
Vibrational and electronic entropy of b-cerium and g-cerium measured by inelastic neutron scattering
Time-of-flight ~TOF! inelastic neutron-scattering spectra were measured on b-cerium ~double hcp! and g-cerium ~fcc! near the phase-transition temperature. Phonon densities of states ~DOS! and crystal-field levels were extracted from the TOF spectra. A softening of the phonon DOS occurs in the transition from bto g-cerium, accounting for an increase in vibrational entropy of DSvib 5(0.0960.05)kB...
The first synthesis of the racemic 8-deoxy WP3688-2 angucycline antibiotic (3), with characteristic cis-hydroxy groups at C-4 a and C-12b, is reported. Key steps involve the coupling, mediated by samarium diiodide, of the bicyclic trione 37 to the tricyclic cis-diol 39. Biomimetic aldol cyclization of the corresponding dione 41 gave a mixture of the tetracyclic cis- and trans-3,4a-diols 42 and ...
Abstract— In the present paper, we have investigated the high-pressure structural phase transition of cerium monopnictide. The three-body potential model has been used to study the structural properties of this compound. Phase transition pressures are associated with a sudden collapse in volume. The phase transition pressures and associated volume collapses obtained from present potential model...
We propose a new framework for first-principles calculations of heavy-fermion materials. These are described in terms of the Kondo lattice Hamiltonian with the parameters extracted from a realistic density functional based calculation which is then solved using continuous-time quantum Monte Carlo method and dynamical mean field theory. As an example, we show our results for the Néel temperature...
Cerium conversion coatings are a potential alternative to chromium conversion coatings for improving the corrosion resistance of magnesium alloys. This study detailed the microstructure and corrosion resistance of cerium conversion coatings on AZ31 magnesium plates treated in 0.05 kmolm 3 cerium nitrate solution, with and without 0.25 kmolm 3 hydrogen peroxide. The results indicate that the cor...
The morphology and composition of CeOx films prepared by r.f. magnetron sputtering on a graphite foil have been investigated mainly by using microscopy methods. This study presents the formation of nanocrystalline layers with porous structure due to the modification of a carbon support and the formation of cerium carbide crystallites as a result of the deposition process. Chemical analyses of t...
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