Pure and mixed lanthanum and cerium oxides were synthesized via a reverse microemulsion-templated route. This approach yields highly homogeneous and phase-stable mixed oxides with high surface areas across the entire range of La:Ce ratios from pure lanthana to pure ceria. Surprisingly, all mixed oxides show the fluorite crystal structure of ceria, even for 10 lanthanum contents as high as 90%. ...

We report a single step technique of synthesizing particle-agglomerated, amorphous 3-D nanostructures of Al and Si oxides on powder-fused aluminosilicate ceramic plates and a simple novel method of wafer-foil ablation to fabricate crystalline nanostructures of Al and Si oxides at ambient conditions. We also propose a particle size prediction mechanism to regulate the size of vapor-condensed agg...

Thin silicon carbide films have been deposited by chemical vapor deposition on p-type ~100! silicon substrates. The composition and bonds formed in these films have been analyzed by x-ray photoelectron spectroscopy ~XPS! and infrared spectroscopy. The native surface oxide on the silicon carbide surface induced by air exposure has also been studied. Several phases are detected in the near-surfac...

The crystal structure and d.c. electrical conductivity of a series of homogeneous mixed rare-earth oxides in LnPrO3+y (Ln=Y and lanthanide ion) system are reported. It is found that the ionic size of Ln determines the crystal structure of the oxides in this series. LaPrO3+y and CePrO3+y crystallise in the fluorite structure(fcc), whereas the remaining oxides adopt the C-type rare-earth oxide st...

In this work we investigate the effect of iron oxide embedded in silica matrices as a function of Fe/Si molar ratio and sol pH. To achieve homogeneous dispersion of iron oxide particles, iron nitrate nonahydrate was dissolved in hydrogen peroxide and was mixed with tetraethyl orthosilicate and ethanol in a sol-gel synthesis method. Increasing the calcination temperature led to a reduction in su...

Phase stabilities of Hf-Si-O and Zr-Si-O have been studied with first-principles and thermodynamic modeling. From the obtained thermodynamic descriptions, phase diagrams pertinent to thin film processing were calculated. We found that the relative stability of the metal silicates with respect to their binary oxides plays a critical role in silicide formation. It was observed that both the HfO2/...

recently, the al2o3–tio2–zro2 system has found valuable applications, particularly, as a support for nox storage–reduction (nsr) catalysts. nanocomposite powders were prepared from the co-precipitation method in inorganic precursors. the behaviors of mixed oxide nanoparticles under ultrasonic irradiation, such as dispersion, and crushing were studied. phase transformations, crystallite size, an...

In this paper, the effects of different aluminum to silicon ratios in silicate chains of calcium silicate hydrates (C-S-H) are evaluated on the diffusion coefficient of chloride ions by molecular dynamics method. Tobermorite is a crystalline phase that is used for studying C-S-H properties in nano scale, because of its analogous chemical composition to C-S-H. Aluminum incorporation in C-S-H and...

The results of electronic structure modeling of plutonium and americium higher oxide molecules (actinide oxidation states VI through VIII) by two-component relativistic density functional theory are presented. Ground-state equilibrium molecular structures, main features of charge distributions, and energetics of AnO3, AnO4, An2On (An=Pu, Am), and PuAmOn, n = 6-8, are determined. In all cases, m...

We present a case that passivated contacts based on a thin tunneling oxide layer, combined with a transport layer with properly selected workfunction and band offsets, can lead to high efficiency c-Si solar cells. Passivated contacts contribute to cell efficiency as well as design flexibility, process robustness, and a simplified process flow. Material choices for the transport layer are examin...