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We give a new, manifestly spacetime-supersymmetric method for calculating superstring scattering amplitudes, using the ghost pyramid, that is simpler than all other known methods. No pictures nor non-vertex insertions are required other than the usual b and c ghosts of the bosonic string. We evaluate some tree and loop amplitudes as examples.
The present work establishes a process for the anodic growth of self-organized TiO(2) nanotubes with a single-walled morphology. This yields not only a much more defined tube geometry but also provides a significant increase in properties and prospect for a wide range of TiO(2) nanotube applications.
Pt decorated TiO2 has, over the past decades, been a key material for photocatalytic hydrogen production. The present work shows that growing anodic self-organized TiO2 nanotubes from Ti-Pt alloy with a low Pt content of 0.2 at% leads to oxide nanotube layers that are self-decorated with Pt nanoparticles of 4-5 nm in diameter. The average particle spacing… (More)
Peas in a pod: A highly aligned Au(np)@TiO2 photocatalyst was formed by self-organizing anodization of a Ti substrate followed by dewetting of a gold thin film. This leads to exactly one Au nanoparticle (np) per TiO2 nanocavity. Such arrays are highly efficient photocatalysts for hydrogen generation from ethanol.
The present article reviews the current status of using TiO(2) nanotubes in Grätzel-type, dye-sensitized solar cells and extends the overview with the latest results and findings. Critical factors in tube geometry (length, diameter, top morphology), crystal structure (amorphous, anatase, rutile) as well as factors affecting dye loading or electron mobility… (More)
We report a process for the fabrication of an anatase TiO(2) mesosponge (TMS) layer by an optimized Ti anodization process in a hot glycerol electrolyte followed by a suitable etching process. Such layers can easily be grown to >10 microm thickness and have regular channels and structural features in the 5-20 nm range. The layers show high photocatalytic… (More)
In this paper a simple signal segmentation algorithm is introduced. The algorithm determines the epochs of signal components of interest based on signal characteristic such as amplitude, slope, deflection width, or distance between neighboring deflections. The epochs are segmented indirectly by means of a slope trace wave that traces a signal with its… (More)
Electrochemical anodization of low-concentration (0.02-0.2 at% Au) TiAu alloys in a fluoride electrolyte leads to self-organized TiO2 nanotubes that show a controllable, regular in situ decoration with elemental Au nanoclusters of ≈5 nm in diameter. The degree of self-decoration can be adjusted by the Au concentration in the alloy and the anodization time.… (More)
The present work shows a significant enhancement of the photoelectrochemical water-splitting performance of anodic TiO(2) nanotube layers grown on low concentration (0.01-0.2 at% Ru) Ti-Ru alloys. Under optimized preparation conditions (0.05 at% Ru, 450 °C annealing) the water splitting rate of the oxide tubes could be 6-fold increased. Moreover, the… (More)