Conversion of Methane into Methanol and Ethanol over Nickel Oxide on Ceria–Zirconia Catalysts in a Single Reactor

The conversion of methane into alcohols under moderate reaction conditions is a promising technology for converting stranded methane reserves into liquids that can be transported in pipelines and upgraded to value‐added chemicals. We demonstrate that a catalyst consisting of small nickel oxide clusters supported on ceria–zirconia (NiO/CZ) can convert methane to methanol and ethanol in a single, steady‐state process at 723 K using O₂ as an abundantly available oxidant. The presence of steam is required to obtain alcohols rather than CO₂ as the product of catalytic combustion. The unusual activity of this catalyst is attributed to the synergy between the small Lewis acidic NiO clusters and the redox‐active CZ support, which also stabilizes the small NiO clusters.     

Au, Ge, and AuGe nanoparticles fabricated by laser ablation

A eutectic AuGe target immersed in distilled water was ablated by pulsed ultraviolet laser light. The structure of the ablated material was investigated by high-resolution transmission electron microscopy (HRTEM). The images show formation of nanowire structures of AuGe up to 100 nm in length, with widths of 5–10 nm. These nanostructures have Ge content significantly lower than the target material. Electron diffraction demonstrates that they crystallize in the α-AuGe structure. For comparison, laser ablation of pure Au and pure Ge targets was also performed under the same conditions. HRTEM shows that Ge forms spherical nanoparticles with a characteristic size of ~30 nm. Au forms spherical nanoparticles with diameters of ~10 nm. Similar to AuGe, it also forms chainlike structures with substantially lower aspect ratio.     

Scaling analysis of coating of a plate or a fiber

The problem of coating a plate or a fiber through their withdrawal from a large reservoir was treated in the literature in various limiting cases. In the present paper, interpolation expressions are derived by scaling for Newtonian, Bingham, and viscoelastic fluids. The scaling analysis was also employed to explain the sharp increase in film thickness produced by inertia and the occurrence of a maximum thickness for an optimum velocity. It is also shown that, for a viscoelastic fluid, the film thickness tends to a finite value at very large withdrawal rates. An explanation is also provided for the existence of a maximum film thickness for an optimum surfactant concentration.     

Size-dependent tunneling and optical spectroscopy of CdSe quantum rods

Photoluminescence excitation spectroscopy and scanning-tunneling spectroscopy are used to study the electronic states in CdSe quantum rods that manifest a transition from a zero-dimensional to a one-dimensional quantum-confined structure. Both optical and tunneling spectra show that the level structure depends primarily on the diameter of the rod and not its length. With increasing diameter, the band gap and the excited state level spacings shift to the red. The level structure was assigned using a multiband effective-mass model, showing a similar dependence on rod dimensions.     

Free products of kω-topological groups with normal amalgamation

It is shown in this paper that if A is a closed normal subgroup of k_ω-topological groups G and H, then the free product of G and H with A amalgamated, G1_AH, exists, is Hausdorff and indeed a k_ω-group.