Michael Becker

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The absorption changes that occur in reaction centers of the photosynthetic bacterium Rhodopseudomonas sphaeroides during the initial photochemical electron-transfer reaction have been examined. Measurements were made between 740 and 1300 nm at 295 and 80 K by using a pulse-probe technique with 610-nm, 0.8-ps flashes. An excited singlet state of the(More)
Nitrogen-containing functional groups were generated on the surface of partially oxidized multi-walled carbon nanotubes (CNTs) via post-treatment in ammonia. The treatment temperature was varied in order to tune the amount and type of nitrogen- and oxygen-containing functional groups, which were studied using high-resolution X-ray photoelectron spectroscopy(More)
Progress in modeling and measuring temperature effects in vibrating beam gallium orthophosphate (GaPO4) resonators are reported. In addition to the well known thicknessshear AT-cut, temperature compensated cuts exist in GaPO4 for length extensional modes. Experimental evidence of temperature compensated cut in GaPO4 rectangular beam resonator vibrating in(More)
Silicon (Si) nanoparticles (NPs) were synthesized by transforming a Si wafer surface to ammonium silicon hexafluoride (ASH) or (NH(4))(2)SiF(6) under acid vapor treatment. Si-NPs which were found to be embedded within the polycrystalline (ASH) layer exhibit a strong green-orange photoluminescence (PL). Differential PL measurements revealed a major double(More)
An array comprising 4 intermittent (retracting) rotorods, 3 ("swingshield") rotoslides and one Burkard (Hirst) automatic volumetric spore trap was operated on an urban rooftop during 70 periods of 9, 15 or 24 hours in late summer. Standard sampling procedures were utilized and recoveries of pollens as well as spores of Alternaria, Epicoccum, Pithomyces and(More)
Variations of the spectra of plasmonic light emitted from the junction of a scanning tunneling microscope have been observed for different lateral positions of the scanning tunneling microscope tip on a Au(111) surface. Subnanometer spatial variations of the light emission intensity over a triangular island and in the vicinity of surface step edges have(More)
CO adsorption at 1 MPa on Cu-Zn stearate colloids and supported Cu catalysts was studied in situ by attenuated total reflection infrared (ATR-IR) spectroscopy. Subsequent to thorough reduction by H(2), the IR band at 2110-2070 cm(-1) due to linearly adsorbed CO on clean metallic Cu was always observed initially on all Cu catalysts. During the exposure of(More)
GaN-on-diamond device cooling can be enhanced by reducing the effective thermal boundary resistance (TBReff) of the GaN/diamond interface. The thermal properties of this interface and of the polycrystalline diamond grown onto GaN using SiN and AlN barrier layers as well as without any barrier layer under different growth conditions are investigated and(More)
PbZrO3/SrRuO3/SrTiO3 (100) epitaxial heterostructures with different thickness of the PbZrO3 (PZO) layer (dPZO ∼ 5–160 nm) were fabricated by pulsed laser deposition. The ultrathin PZO films (dPZO 10 nm) were found to possess a rhombohedral structure. On increasing the PZO film thickness, a bulk like orthorhombic phase started forming in the film with dPZO(More)
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