Here, we present the low-temperature (∼600 °C) solution combustion method for the fabrication of CoFe 2 O 4 , NiFe 2 O 4 , and Co 0.5 Ni 0.5 Fe 2 O 4 nanoparticles (NPs) of 12–64 nm range in pure cubic spinel structure, by adjusting the oxidant (nitrate ions)/reductant (glycine) ratio in the reaction mixture. Although nitrate ions/glycine (N/G) ratios of 3 and 6 were used for the synthesis, phase-pure NPs could be obtained only for the N/G ratio of 6. For the N/G ratio 3, certain amount of Ni 2+ cations was reduced to metallic nickel. The NH 3 gas generated during the thermal decomposition of the amino acid (glycine, H 2 NCH 2 COOH) induced the reduction reaction. X-ray diffraction (XRD), Raman spectroscopy, vibrating sample magnetometry, and X-ray photoelectron spectroscopy techniques were utilized to characterize the synthesized materials. XRD analyses of the samples indicate that the Co 0.5 Ni 0.5 Fe 2 O 4 NPs have lattice parameter larger than that of NiFe 2 O 4 , but smaller than that of CoFe 2 O 4 NPs. Although the saturation magnetization ( M s ) of Co 0.5 Ni 0.5 Fe 2 O 4 NPs lies in between the saturation magnetization values of CoFe 2 O 4 and NiFe 2 O 4 NPs, high coercivity ( H c , 875 Oe) of the NPs indicate their hard ferromagnetic behavior. Catalytic behavior of the fabricated spinel NPs revealed that the samples containing metallic Ni are active catalysts for the degradation of 4-nitrophenol in aqueous medium.

We present a detailed structural analysis for small Tin (n = 2-15) clusters based on ab initio quantum mechanical calculations of their binding energies, frontier orbital gaps, and second energy derivatives. Local density approximation calculations revealed that while the smaller clusters (n < or = 8) prefer hexagonal atomic arrays with bulklike crystal symmetry, the bigger clusters prefer pentagonal atomic arrays. From the stability criteria of the magic number clusters we could identify three magic number clusters Ti7, Ti13, and Ti15. While the most stable configuration of Ti7 is a decahedral bipyramid induced by tetrahedral atomic arrays, the most stable configuration of Ti13 is an icosahedron. The other stable cluster Ti15 takes a closed-shell icosahedron-like configuration with both pentagonal and hexagonal symmetries. The stability of the Tin clusters strongly depends on their geometries and charge states. The HOMO-LUMO gap of the Tin clusters approaches its bulk value for n > 8. While there is not much difference between the HOMO and LUMO isosurface charge distributions for the Ti7 and Ti13 clusters in their most stable configurations, they are very different in the case of Ti15. Such a distinct charge distribution in Ti15 indicates its singular chemical selectivity over the other two magic number clusters.

Atomic clusters of TiO(2) are modeled by means of state-of-the-art techniques to characterize their structural, electronic and optical properties. We combine ab initio molecular dynamics, static density functional theory, time-dependent density functional theory, and many body techniques, to provide a deep and comprehensive characterization of these systems. TiO(2) clusters can be considered as the starting seeds for the synthesis of larger nanostructures, which are of technological interest in photocatalysis and photovoltaics. In this work, we prove that clusters with anatase symmetry are energetically stable and can be considered as the starting seeds to growth much larger and complex nanostructures. The electronic gap of these inorganic molecules is investigated, and shown to be larger than the optical gap by almost 4 eV. Therefore, strong excitonic effects appear in these systems, much more than in the corresponding bulk phase. Moreover, the use of various levels of theory demonstrates that charge transfer effects play an important role under photon absorption, and therefore the use of adiabatic functionals in time dependent density functional theory has to be carefully evaluated.

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The corrosion resistance of commercial aluminium alloy (2024) and binary Al-Cu x and Al-Mg x alloys reinforced with TiC particles using a pressureless infiltration method has been evaluated in 3.5% NaCl solution using potentiodynamic polarization curves and linear polarization resistance measurements. The TiC preforms were sintered at 1250, 1350 and 1450°C and infiltrated in the range of 900-1200°C under argon atmosphere. Some specimens were heat treated at 530°C for 150 min, water quenched and subsequently artificially aged at 190°C for 12 h in an argon atmosphere and naturally aged at room temperature for 96 h, respectively. The corrosion resistance of the composites was evaluated as a function of the addition of Cu and Mg into the aluminium. In all cases pitting corrosion was observed with or without additions of Cu or Mg, but these elements increased the anodic corrosion current. However, it was found that addition of TiC particles in the composite without heat treatment reduced the anodic current density and the number and size of pits in the Al-2024 alloy. When the heat treatment was applied to the composite, either artificially or naturally aged, the anodic current density of the Al-2024 alloy increased.

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We have performed first principles total energy calculations to investigate the structural and reactivity parameters of novel N12X12H12 (X=B, Al, Ga, In, Tl) nitrides, in their coronene‐like (C24H12) structure to simulate these sheets. The exchange and correlations potential energies are treated in the Generalized Gradient Approximation (GGA), and the Local Density Approximation (LDA) within the parameterization of Perdew‐Wang and Perdew‐Burke‐Ernzerhof (PWC, PBE) and the double Numeric plus polarization (DNP) atomic base. The chemical potential, hardness and electrophilicity index, as well as bond length are reported. The bond length of the structures is similar to the bulk. The gap between the HOMO and LUMO decreases from BN (5.18 eV) to TlN (1.76 eV). At the same time, the polarity increases except for TlN. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)