Formation of environmentally persistent free radicals (EPFRs) on ZnO at room temperature: Implications for the fundamental model of EPFR generation.

Environmentally persistent free radicals (EPFRs) have significant environmental and public health impacts. In this study, we demonstrate that EPFRs formed on ZnO nanoparticles provide two significant surprises. First, EPR spectroscopy shows that phenoxy radicals form readily on ZnO nanoparticles at room temperature, yielding EPR signals similar to those previously measured after 250°C exposures. Vibrational spectroscopy supports the conclusion that phenoxy-derived species chemisorb to ZnO nanoparticles under both exposure temperatures. Second, DFT calculations indicate that electrons are transferred from ZnO to the adsorbed organic (oxidizing the Zn), the opposite direction proposed by previous descriptions of EPFR formation on metal oxides.

High-throughput Toroidal Grating Beamline for Photoelectron Spectroscopy at CAMD.

A 5 meter toroidal grating (5m-TGM) beamline has been commissioned to deliver 28 mrad of bending magnet radiation to an ultrahigh vacuum endstation chamber to facilitate angle resolved photoelectron spectroscopy. The 5m-TGM beamline is equipped with Au-coated gratings with 300, 600 and 1200 lines/mm providing monochromatized synchrotron radiation in the energy ranges 25-70 eV, 50-120 eV and 100-240 eV, respectively. The beamline delivers excellent flux (~1014-1017 photons/sec/100mA) and a combined energy resolution of 189 meV for the beamline (at 1.0 mm slit opening) and HA-50 hemispherical analyzer was obtained at the Fermi level of polycrystalline gold crystal. Our preliminary photoelectron spectroscopy results of phenol adsorption on TiO2 (110) surface reveals the metal ion (Ti) oxidation.

Real-time holographic motion picture camera capable of recording front surface detail from a random velocity vector.

A new holographic technique has been developed that allows the resolution of front surface detail to be holographically recorded from a scene having a relatively large total motion during the exposure, i.e., the total motion of the scene during the exposure is large, relative to the allowed path length change of the signal beam. The new technique has been employed as a holographic camera and consequently produced the first real-time, true three-dimensional motion picture of a moving scene with resolution of front surface detail [R. L. Kurtz and L. M. Perry, Appl. Opt. 12, 888 (1973)]. A composite of this technique provides for the moving scene to have a randomly oriented velocity vector. Evidence of the maximum allowable total scene motion for a single velocity component is provided where the laser source was a continuous wave argon laser.

Experimental Investigation of a Holographic System that Records Front Surface Detail from a Scene Moving at High Velocities.

Any motion of the scene during the exposure of a hologram results in a spatial modulation of the recorded fringe contrast. On reconstruction, this produces a spatial amplitude modulation of the reconstructed wavefront, which results in blurring of the image not unlike that of a conventional photograph. The concept of motion holography has been aptly described theoretically by D. B. Neumann. This paper presents and discusses the experimental investigation of a new holographic technique that allows resolution of front surface detail for scene velocities on the order of 9 x 10(5) cm/sec.

A holographic technique for recording a hypervelocity projectile with front surface resolution.

Any motion of the scene during the exposure of a hologram results in a spatial modulation of the recorded fringe contrast. On reconstruction, this produces a spatial amplitude modulation of the reconstructed wavefront, which results in a blurring of the image, not unlike that of a conventional photograph. For motion of the scene sufficient to change the path length of the signal arm by a half wavelength, this blurring is generally prohibitive. This paper describes a proposed holographic technique which offers promise for front light resolution of targets moving at high speeds, heretofore unobtainable by conventional methods.